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Sample records for islet hormonal responses

  1. Synergism by individual macronutrients explains the marked early GLP-1 and islet hormone responses to mixed meal challenge in mice.

    PubMed

    Ahlkvist, L; Vikman, J; Pacini, G; Ahrén, B

    2012-10-10

    Apart from glucose, proteins and lipids also stimulate incretin and islet hormone secretion. However, the glucoregulatory effect of macronutrients in combination is poorly understood. We therefore developed an oral mixed meal model in mice to 1) explore the glucagon-like peptide-1 (GLP-1) and islet hormone responses to mixed meal versus isocaloric glucose, and 2) characterize the relative contribution of individual macronutrients to these responses. Anesthetized C57BL/6J female mice were orally gavaged with 1) a mixed meal (0.285 kcal; glucose, whey protein and peanut oil; 60/20/20% kcal) versus an isocaloric glucose load (0.285 kcal), and 2) a mixed meal (0.285 kcal) versus glucose, whey protein or peanut oil administered individually in their mixed meal caloric quantity, i.e., 0.171, 0.055 and 0.055 kcal, respectively. Plasma was analyzed for glucose, insulin and intact GLP-1 before and during oral challenges. Plasma glucose was lower after mixed meal versus after isocaloric glucose ingestion. In spite of this, the peak insulin response (P=0.02), the peak intact GLP-1 levels (P=0.006) and the estimated β-cell function (P=0.005) were higher. Furthermore, the peak insulin (P=0.004) and intact GLP-1 (P=0.006) levels were higher after mixed meal ingestion than the sum of responses to individual macronutrients. Compared to glucose alone, we conclude that there is a marked early insulin response to mixed meal ingestion, which emanates from a synergistic, rather than an additive, effect of the individual macronutrients in the mixed meal and is in part likely caused by increased levels of GLP-1. PMID:22750278

  2. Pancreatic Islet Responses to Metabolic Trauma.

    PubMed

    Burke, Susan J; Karlstad, Michael D; Collier, J Jason

    2016-09-01

    Carbohydrate, lipid, and protein metabolism are largely controlled by the interplay of various hormones, which includes those secreted by the pancreatic islets of Langerhans. While typically representing only 1% to 2% of the total pancreatic mass, the islets have a remarkable ability to adapt to disparate situations demanding a change in hormone release, such as peripheral insulin resistance. There are many different routes to the onset of insulin resistance, including obesity, lipodystrophy, glucocorticoid excess, and the chronic usage of atypical antipsychotic drugs. All of these situations are coupled to an increase in pancreatic islet size, often with a corresponding increase in insulin production. These adaptive responses within the islets are ultimately intended to maintain glycemic control and to promote macronutrient homeostasis during times of stress. Herein, we review the consequences of specific metabolic trauma that lead to insulin resistance and the corresponding adaptive alterations within the pancreatic islets. PMID:26974425

  3. Compensatory Islet Response to Insulin Resistance Revealed by Quantitative Proteomics

    PubMed Central

    Gedeon, Nicholas; Kahraman, Sevim; De Jesus, Dario F.; Bhatt, Shweta; Kim, Jong-Seo; Clauss, Therese RW; Camp, David G.; Smith, Richard D.; Qian, Wei-Jun; Kulkarni, Rohit N.

    2015-01-01

    Compensatory islet response is a distinct feature of the pre-diabetic insulin resistant state in humans and rodents. To identify alterations in the islet proteome that characterize the adaptive response, we analyzed islets from five-month-old male control, high-fat diet fed (HFD) or obese ob/ob mice by LC-MS(/MS) and quantified ~1,100 islet proteins (at least two peptides) with a false discovery rate <1%. Significant alterations in abundance were observed for ~350 proteins between groups. A majority of alterations were common to both models, and the changes of a subset of ~40 proteins and 12 proteins were verified by targeted quantification using selected reaction monitoring and Western blots, respectively. The insulin resistant islets in both groups exhibited reduced expression of proteins controlling energy metabolism, oxidative phosphorylation, hormone processing, and secretory pathways. Conversely, an increased expression of molecules involved in protein synthesis and folding suggested effects in endoplasmic reticulum stress response, cell survival, and proliferation in both insulin resistant models. In summary, we report a unique comparison of the islet proteome that is focused on the compensatory response in two insulin resistant rodent models that are not overtly diabetic. These data provide a valuable resource of candidate proteins to the scientific community to undertake further studies aimed at enhancing β-cell mass in patients with diabetes. The data are available via the MassIVE repository, with accession MSV000079093. PMID:26151086

  4. Compensatory islet response to insulin resistance revealed by quantitative proteomics

    SciTech Connect

    El Ouaamari, Abdelfattah; Zhou, Jian -Ying; Liew, Chong Wee; Shirakawa, Jun; Dirice, Ercument; Gedeon, Nicholas; Kahraman, Sevim; De Jesus, Dario F.; Bhatt, Shweta; Kim, Jong -Seo; Clauss, Therese R. W.; Camp, II, David G.; Smith, Richard D.; Qian, Wei -Jun; Kulkarni, Rohit N.

    2015-07-07

    Compensatory islet response is a distinct feature of the pre-diabetic insulin resistant state in humans and rodents. To identify alterations in the islet proteome that characterize the adaptive response, we analyzed islets from five-month-old male control, high-fat diet fed (HFD) or obese ob/ob mice by LC-MS(/MS) and quantified ~1,100 islet proteins (at least two peptides) with a false discovery rate <1%. Significant alterations in abundance were observed for ~350 proteins between groups. A majority of alterations were common to both models, and the changes of a subset of ~40 proteins and 12 proteins were verified by targeted quantification using selected reaction monitoring and Western blots, respectively. The insulin resistant islets in both groups exhibited reduced expression of proteins controlling energy metabolism, oxidative phosphorylation, hormone processing, and secretory pathways. Conversely, an increased expression of molecules involved in protein synthesis and folding suggested effects in endoplasmic reticulum stress response, cell survival, and proliferation in both insulin resistant models. In conclusion, we report a unique comparison of the islet proteome that is focused on the compensatory response in two insulin resistant rodent models that are not overtly diabetic. In conclusion, these data provide a valuable resource of candidate proteins to the scientific community to undertake further studies aimed at enhancing β-cell mass in patients with diabetes. The data are available via the MassIVE repository, with accession MSV000079093.

  5. Compensatory islet response to insulin resistance revealed by quantitative proteomics

    DOE PAGESBeta

    El Ouaamari, Abdelfattah; Zhou, Jian -Ying; Liew, Chong Wee; Shirakawa, Jun; Dirice, Ercument; Gedeon, Nicholas; Kahraman, Sevim; De Jesus, Dario F.; Bhatt, Shweta; Kim, Jong -Seo; et al

    2015-07-07

    Compensatory islet response is a distinct feature of the pre-diabetic insulin resistant state in humans and rodents. To identify alterations in the islet proteome that characterize the adaptive response, we analyzed islets from five-month-old male control, high-fat diet fed (HFD) or obese ob/ob mice by LC-MS(/MS) and quantified ~1,100 islet proteins (at least two peptides) with a false discovery rate <1%. Significant alterations in abundance were observed for ~350 proteins between groups. A majority of alterations were common to both models, and the changes of a subset of ~40 proteins and 12 proteins were verified by targeted quantification using selectedmore » reaction monitoring and Western blots, respectively. The insulin resistant islets in both groups exhibited reduced expression of proteins controlling energy metabolism, oxidative phosphorylation, hormone processing, and secretory pathways. Conversely, an increased expression of molecules involved in protein synthesis and folding suggested effects in endoplasmic reticulum stress response, cell survival, and proliferation in both insulin resistant models. In conclusion, we report a unique comparison of the islet proteome that is focused on the compensatory response in two insulin resistant rodent models that are not overtly diabetic. In conclusion, these data provide a valuable resource of candidate proteins to the scientific community to undertake further studies aimed at enhancing β-cell mass in patients with diabetes. The data are available via the MassIVE repository, with accession MSV000079093.« less

  6. Enhanced insulin sensitivity mediated by adipose tissue browning perturbs islet morphology and hormone secretion in response to autonomic nervous activation in female mice.

    PubMed

    Omar, Bilal A; Kvist-Reimer, Martina; Enerbäck, Sven; Ahrén, Bo

    2016-01-01

    Insulin resistance results in a compensatory increase in insulin secretion to maintain normoglycemia. Conversely, high insulin sensitivity results in reduced insulin secretion to prevent hypoglycemia. The mechanisms for this inverse adaptation are not well understood. We utilized highly insulin-sensitive mice, due to adipocyte-specific overexpression of the FOXC2 transcription factor, to study mechanisms of the reversed islet adaptation to increased insulin sensitivity. We found that Foxc2TG mice responded to mild hyperglycemia with insulin secretion significantly lower than that of wild-type mice; however, when severe hyperglycemia was induced, Foxc2TG mice demonstrated insulin secretion equal to or greater than that of wild-type mice. In response to autonomic nervous activation by 2-deoxyglucose, the acute suppression of insulin seen in wild-type mice was absent in Foxc2TG mice, suggesting impaired sympathetic signaling to the islet. Basal glucagon was increased in Foxc2TG mice, but they displayed severely impaired glucagon responses to cholinergic and autonomic nervous stimuli. These data suggest that the autonomic nerves contribute to the islet adaptation to high insulin sensitivity, which is compatible with a neuro-adipo regulation of islet function being instrumental for maintaining glucose regulation. PMID:26530152

  7. Improvement of islet function in a bioartificial pancreas by enhanced oxygen supply and growth hormone releasing hormone agonist

    PubMed Central

    Ludwig, Barbara; Rotem, Avi; Schmid, Janine; Weir, Gordon C.; Colton, Clark K.; Brendel, Mathias D.; Neufeld, Tova; Block, Norman L.; Yavriyants, Karina; Steffen, Anja; Ludwig, Stefan; Chavakis, Triantafyllos; Reichel, Andreas; Azarov, Dimitri; Zimermann, Baruch; Maimon, Shiri; Balyura, Mariya; Rozenshtein, Tania; Shabtay, Noa; Vardi, Pnina; Bloch, Konstantin; de Vos, Paul; Schally, Andrew V.; Bornstein, Stefan R.; Barkai, Uriel

    2012-01-01

    Islet transplantation is a feasible therapeutic alternative for metabolically labile patients with type 1 diabetes. The primary therapeutic target is stable glycemic control and prevention of complications associated with diabetes by reconstitution of endogenous insulin secretion. However, critical shortage of donor organs, gradual loss in graft function over time, and chronic need for immunosuppression limit the indication for islet transplantation to a small group of patients. Here we present a promising approach to address these limitations by utilization of a macrochamber specially engineered for islet transplantation. The s.c. implantable device allows for controlled and adequate oxygen supply and provides immunological protection of donor islets against the host immune system. The minimally invasive implantable chamber normalized blood glucose in streptozotocin-induced diabetic rodents for up to 3 mo. Sufficient graft function depended on oxygen supply. Pretreatment with the growth hormone-releasing hormone (GHRH) agonist, JI-36, significantly enhanced graft function by improving glucose tolerance and increasing β-cell insulin reserve in rats thereby allowing for a reduction of the islet mass required for metabolic control. As a result of hypervascularization of the tissue surrounding the device, no relevant delay in insulin response to glucose changes has been observed. Consequently, this system opens up a fundamental strategy for therapy of diabetes and may provide a promising avenue for future approaches to xenotransplantation. PMID:22393012

  8. Characterization of the Insulin Reservoir in Rat Islets of Langerhans: Evaluation of Hormone Synthesis, Processing, Storage and Secretion.

    NASA Astrophysics Data System (ADS)

    Gishizky, Mikhail Lev

    1988-12-01

    It has been reported that acute glucose stimulation of islets results in the preferential release of newly synthesized insulin. This suggests that the large islet hormone reservoir may represent a heterogeneous pool. In these investigation we characterized the nature of the islet hormone reservoir and evaluated possible mechanisms responsible for its regulation. Our studies demonstrated that under stimulated secretory conditions normal pancreatic islets secreted newly synthesized insulin in preference to their large stored hormone content. The preferential release pattern was observed with all secretogogues tested and was not restricted to a specific subset of islets. Aided by computer model analysis, we proposed that the islet insulin reservoir represented a heterogeneous pool composed of at least two hypothetical compartments--labile and stable. Evaluation of the islet hormone reservoir under different in vivo and in vitro conditions demonstrated that in response to prolonged stimulation, the hypothetical labile compartment apparently decreased in size. This augmentation in the compartmental character was associated with (1) decreased amount of insulin secreted, (2) increased proportion of newly synthesized insulin secreted, and (3) an increased rate of prohormone conversion with no alteration in the rate of hormone synthesis. Thus parameters which defined the islet hormone reservoir represented a dynamic system that responded to the islets milieu. Preferential release of newly synthesized insulin was not an intrinsic property of insulin secreting cells. Furthermore, the mechanism responsible for the compartmentalization of the insulin reservoir did not discriminate between the two non-allelic murine insulins. Our studies indicated that differences in the amino acid structure of the two prohormones apparently resulted in proinsulin I being transported to the conversion compartment faster than proinsulin II. However, glucose regulation of the synthesis and

  9. Intracranial pancreatic islet transplantation increases islet hormone expression in the rat brain and attenuates behavioral dysfunctions induced by MK-801 (dizocilpine).

    PubMed

    Bloch, Konstantin; Gil-Ad, Irit; Tarasenko, Igor; Vanichkin, Alexey; Taler, Michal; Hornfeld, Shay Henry; Vardi, Pnina; Weizman, Abraham

    2015-06-01

    The treatment of rodents with non-competitive antagonist of the N-Methyl-D-aspartate (NMDA) receptor, MK-801 (dizocilpine), induces symptoms of psychosis, deficits in spatial memory and impairment of synaptic plasticity. Recent studies have suggested that insulin administration might attenuate the cognitive dysfunctions through the modulatory effect on the expression of NMDA receptors and on the brain insulin signaling. Intrahepatic pancreatic islet transplantation is known as an efficient tool for correcting impaired insulin signaling. We examined the capacity of syngeneic islets grafted into the cranial subarachnoid cavity to attenuate behavioral dysfunctions in rats exposed to MK-801. Animals were examined in the open field (OF) and the Morris Water Maze (MWM) tests following acute or subchronic administration of MK-801. We found well-vascularized grafted islets expressing insulin, glucagon and somatostatin onto the olfactory bulb and prefrontal cortex. Significantly higher levels of insulin were detected in the hippocampus and prefrontal cortex of transplanted animals compared to the non-transplanted rats. All animals expressed normal peripheral glucose homeostasis for two months after transplantation. OF tests revealed that rats exposed to MK-801 treatment, showed hyper-responsiveness in motility parameters and augmented center field exploration compared to intact controls and these effects were attenuated by the grafted islets. Moreover, in the MWM, the rats treated with MK-801 showed impairment of spatial memory that were partially corrected by the grafted islets. In conclusion, intracranial islet transplantation leads to the expression of islet hormones in the brain and attenuates behavioral and cognitive dysfunctions in rats exposed to MK-801 administration without altering the peripheral glucose homeostasis. PMID:25943974

  10. Design Principles of Pancreatic Islets: Glucose-Dependent Coordination of Hormone Pulses

    PubMed Central

    Hoang, Danh-Tai; Hara, Manami; Jo, Junghyo

    2016-01-01

    Pancreatic islets are functional units involved in glucose homeostasis. The multicellular system comprises three main cell types; β and α cells reciprocally decrease and increase blood glucose by producing insulin and glucagon pulses, while the role of δ cells is less clear. Although their spatial organization and the paracrine/autocrine interactions between them have been extensively studied, the functional implications of the design principles are still lacking. In this study, we formulated a mathematical model that integrates the pulsatility of hormone secretion and the interactions and organization of islet cells and examined the effects of different cellular compositions and organizations in mouse and human islets. A common feature of both species was that islet cells produced synchronous hormone pulses under low- and high-glucose conditions, while they produced asynchronous hormone pulses under normal glucose conditions. However, the synchronous coordination of insulin and glucagon pulses at low glucose was more pronounced in human islets that had more α cells. When β cells were selectively removed to mimic diabetic conditions, the anti-synchronicity of insulin and glucagon pulses was deteriorated at high glucose, but it could be partially recovered when the re-aggregation of remaining cells was considered. Finally, the third cell type, δ cells, which introduced additional complexity in the multicellular system, prevented the excessive synchronization of hormone pulses. Our computational study suggests that controllable synchronization is a design principle of pancreatic islets. PMID:27035570

  11. Controlled aggregation of primary human pancreatic islet cells leads to glucose-responsive pseudoislets comparable to native islets

    PubMed Central

    Hilderink, Janneke; Spijker, Siebe; Carlotti, Françoise; Lange, Lydia; Engelse, Marten; van Blitterswijk, Clemens; de Koning, Eelco; Karperien, Marcel; van Apeldoorn, Aart

    2015-01-01

    Clinical islet transplantation is a promising treatment for patients with type 1 diabetes. However, pancreatic islets vary in size and shape affecting their survival and function after transplantation because of mass transport limitations. To reduce diffusion restrictions and improve islet cell survival, the generation of islets with optimal dimensions by dispersion followed by reassembly of islet cells, can help limit the length of diffusion pathways. This study describes a microwell platform that supports the controlled and reproducible production of three-dimensional pancreatic cell clusters of human donor islets. We observed that primary human islet cell aggregates with a diameter of 100–150 μm consisting of about 1000 cells best resembled intact pancreatic islets as they showed low apoptotic cell death (<2%), comparable glucose-responsiveness and increasing PDX1, MAFA and INSULIN gene expression with increasing aggregate size. The re-associated human islet cells showed an a-typical core shell configuration with beta cells predominantly on the outside unlike human islets, which became more randomized after implantation similar to native human islets. After transplantation of these islet cell aggregates under the kidney capsule of immunodeficient mice, human C-peptide was detected in the serum indicating that beta cells retained their endocrine function similar to human islets. The agarose microwell platform was shown to be an easy and very reproducible method to aggregate pancreatic islet cells with high accuracy providing a reliable tool to study cell–cell interactions between insuloma and/or primary islet cells. PMID:25782016

  12. Controlled aggregation of primary human pancreatic islet cells leads to glucose-responsive pseudoislets comparable to native islets.

    PubMed

    Hilderink, Janneke; Spijker, Siebe; Carlotti, Françoise; Lange, Lydia; Engelse, Marten; van Blitterswijk, Clemens; de Koning, Eelco; Karperien, Marcel; van Apeldoorn, Aart

    2015-08-01

    Clinical islet transplantation is a promising treatment for patients with type 1 diabetes. However, pancreatic islets vary in size and shape affecting their survival and function after transplantation because of mass transport limitations. To reduce diffusion restrictions and improve islet cell survival, the generation of islets with optimal dimensions by dispersion followed by reassembly of islet cells, can help limit the length of diffusion pathways. This study describes a microwell platform that supports the controlled and reproducible production of three-dimensional pancreatic cell clusters of human donor islets. We observed that primary human islet cell aggregates with a diameter of 100-150 μm consisting of about 1000 cells best resembled intact pancreatic islets as they showed low apoptotic cell death (<2%), comparable glucose-responsiveness and increasing PDX1, MAFA and INSULIN gene expression with increasing aggregate size. The re-associated human islet cells showed an a-typical core shell configuration with beta cells predominantly on the outside unlike human islets, which became more randomized after implantation similar to native human islets. After transplantation of these islet cell aggregates under the kidney capsule of immunodeficient mice, human C-peptide was detected in the serum indicating that beta cells retained their endocrine function similar to human islets. The agarose microwell platform was shown to be an easy and very reproducible method to aggregate pancreatic islet cells with high accuracy providing a reliable tool to study cell-cell interactions between insuloma and/or primary islet cells. PMID:25782016

  13. Pancreatic and Islet Development and Function: The Role of Thyroid Hormone

    PubMed Central

    Mastracci, Teresa L; Evans-Molina, Carmella

    2014-01-01

    A gradually expanding body of literature suggests that Thyroid Hormone (TH) and Thyroid Hormone Receptors (TRs) play a contributing role in pancreatic and islet cell development, maturation, and function. Studies using a variety of model systems capable of exploiting species-specific developmental paradigms have revealed the contribution of TH to cellular differentiation, lineage decisions, and endocrine cell specification. Moreover, in vitro and in vivo evidence suggests that TH is involved in islet β cell proliferation and maturation; however, the signaling pathway(s) connected with this function of TH/TR are not well understood. The purpose of this review is to discuss the current literature that has defined the effects of TH and TRs on pancreatic and islet cell development and function, describe the impact of hyper- and hypothyroidism on whole body metabolism, and highlight future and potential applications of TH in novel therapeutic strategies for diabetes. PMID:25506600

  14. Different responses of mouse islets and MIN6 pseudo-islets to metabolic stimulation: a note of caution.

    PubMed

    Schulze, Torben; Morsi, Mai; Brüning, Dennis; Schumacher, Kirstin; Rustenbeck, Ingo

    2016-03-01

    MIN6 cells and MIN6 pseudo-islets are popular surrogates for the use of primary beta cells and islets. Even though it is generally agreed that the stimulus-secretion coupling may deviate from that of beta cells or islets, direct comparisons are rare. The present side-by-side comparison of insulin secretion, cytosolic Ca(2+) concentration ([Ca(2+)] i ) and oxygen consumption rate (OCR) points out where similarities and differences exist between MIN6 cells and normal mouse beta cells. In mouse islets and MIN6 pseudo-islets depolarization by 40 mM KCl was a more robust insulinotropic stimulus than 30 mM glucose. In MIN6 pseudo-islets, but not in mouse islets, the response to 30 mM glucose was much lower than to 40 mM KCl and could be suppressed by a preceding stimulation with 40 mM KCl. In MIN6 pseudo-islets, glucose was less effective to raise [Ca(2+)] i than in primary islets. In marked contrast to islets, the OCR response of MIN6 pseudo-islets to 30 mM glucose was smaller than to 40 mM KCl and was further diminished by a preceding stimulation with 40 mM KCl. The same pattern was observed when MIN6 pseudo-islets were cultured in 5 mM glucose. As with insulin secretion memory effects on the OCR remained after wash-out of a stimulus. The differences between MIN6 cells and primary beta cells were generally larger in the responses to glucose than to depolarization by KCl. Thus, the use of MIN6 cells in investigations on metabolic signalling requires particular caution. PMID:26227244

  15. Pancreatic islet cell tumor

    MedlinePlus

    Islet cell tumors; Islet of Langerhans tumor; Neuroendocrine tumors ... In the healthy pancreas, cells called islet cells produce hormones that regulate a several bodily functions. These include blood sugar level and the production of ...

  16. Phenotypic Characterization of MIP-CreERT1Lphi Mice With Transgene-Driven Islet Expression of Human Growth Hormone.

    PubMed

    Oropeza, Daniel; Jouvet, Nathalie; Budry, Lionel; Campbell, Jonathan E; Bouyakdan, Khalil; Lacombe, Julie; Perron, Gabrielle; Bergeron, Valerie; Neuman, Joshua C; Brar, Harpreet K; Fenske, Rachel J; Meunier, Clemence; Sczelecki, Sarah; Kimple, Michelle E; Drucker, Daniel J; Screaton, Robert A; Poitout, Vincent; Ferron, Mathieu; Alquier, Thierry; Estall, Jennifer L

    2015-11-01

    There is growing concern over confounding artifacts associated with β-cell-specific Cre-recombinase transgenic models, raising questions about their general usefulness in research. The inducible β-cell-specific transgenic (MIP-CreERT(1Lphi)) mouse was designed to circumvent many of these issues, and we investigated whether this tool effectively addressed concerns of ectopic expression and disruption of glucose metabolism. Recombinase activity was absent from the central nervous system using a reporter line and high-resolution microscopy. Despite increased pancreatic insulin content, MIP-CreERT mice on a chow diet exhibited normal ambient glycemia, glucose tolerance and insulin sensitivity, and appropriate insulin secretion in response to glucose in vivo and in vitro. However, MIP-CreERT mice on different genetic backgrounds were protected from high-fat/ streptozotocin (STZ)-induced hyperglycemia that was accompanied by increased insulin content and islet density. Ectopic human growth hormone (hGH) was highly expressed in MIP-CreERT islets independent of tamoxifen administration. Circulating insulin levels remained similar to wild-type controls, whereas STZ-associated increases in α-cell number and serum glucagon were significantly blunted in MIP-CreERT(1Lphi) mice, possibly due to paracrine effects of hGH-induced serotonin expression. These studies reveal important new insight into the strengths and limitations of the MIP-CreERT mouse line for β-cell research. PMID:26153246

  17. Islet cell thymidine kinase activity as indicator of islet cell proliferation in rat pancreas

    SciTech Connect

    Swenne, I. )

    1990-01-01

    The activity of thymidine kinase in homogenates of isolated rat islets of Langerhans was measured and correlated with the DNA replicatory activity of the islet cells. Adult and fetal rat islets were cultured in medium with 2.7 or 16.7 mM glucose or 16.7 mM glucose and 1 microgram/ml human growth hormone. In both types of islets, 16.7 mM glucose doubled (3H)thymidine incorporation compared with 2.7 mM glucose, and the addition of growth hormone caused a further increase in DNA replication. TK activity in the islets showed similar changes in response to glucose and growth hormone. The correlation between (3H)thymidine incorporation and TK activity was thus highly significant. Cell-cycle analysis of cultured fetal rat islets showed that TK activity was preferentially expressed during the S phase of the cell cycle. TK activity of freshly isolated islets declined with the age of the animal. In pancreatic sections, the islet cell autoradiographic labeling index after (3H)thymidine administration in vivo likewise declined with age and was correlated with the TK activity in freshly isolated islets. It is suggested that measurements of islet TK activity can be used as index of islet cell proliferation; this method has the distinct advantage of avoiding the cumbersome procedure of preparing and scoring autoradiograms.

  18. Islet Transplantation

    PubMed Central

    2003-01-01

    EXECUTIVE SUMMARY Objective The Medical Advisory Secretariat undertook a review of the evidence on the effectiveness and cost-effectiveness of islet transplantation alone (ITA) in non-uremic patients with type 1 DM who have severe hypoglycemia and uncontrolled diabetes (brittle diabetics). Results In a health technology assessment from Alberta, Guo et al. (2003) stated that limited evidence from the Edmonton series suggested that islet cell transplantation (ITA) (using the Edmonton Protocol) is effective in 1) controlling labile diabetes and 2) protecting against unrecognized hypoglycemia in highly selected patients in the short term. This conclusion by Guo et al. (2003) was based on the results of 11/17 insulin independent patients who were followed up for a median of 20.4 months in the trial by Ryan et al. (2002). In contrast, Paty et al. (2002) concluded that glucagon and epinephrine responses and hypoglycemic symptom recognition were not improved by islet transplantation in patients receiving the procedure in Edmonton, despite prolonged insulin independence and near-normal glycemic control. Paty et al. (2002) (a member of the Edmonton team) examined 7 ITA recipients, 7 type 1 DM patients (nonITA), and 7 nondiabetic control patients. The follow-up for most studies was short. It was suggested that the modifications to the conventional ITA approaches, including the steroid free immunosuppressive regimen, islet preparation in xenoproteins free media and transplantation of fresh islets from multiple donors were associated with improved success. The effects of ITA on beta cell function (secretion of insulin) look promising, however, the effects of ITA on pancreatic alpha cell function (secretion of counter-regulatory hormones such as glucagon and epinephrine) in long standing type 1 diabetes remain unclear. The most important barriers to more widespread islet transplantation using the Edmonton protocol are the availability of sufficient donor organs and the

  19. Hormonal control of inflammatory responses

    PubMed Central

    Farsky, Sandra P.

    1993-01-01

    Almost any stage of inflammatory and immunological responses is affected by hormone actions. This provides the basis for the suggestion that hormones act as modulators of the host reaction against trauma and infection. Specific hormone receptors are detected in the reactive structures in inflamed areas and binding of hormone molecules to such receptors results in the generation of signals that influence cell functions relevant for the development of inflammatory responses. Diversity of hormonal functions accounts for recognized pro- and anti-inflammatory effects exerted by these substances. Most hormone systems are capable of influencing inflammatory events. Insulin and glucocorticoids, however, exert direct regulatory effects at concentrations usually found in plasma. Insulin is endowed with facilitatory actions on vascular reactivity to inflammatory mediators and inflammatory cell functions. Increased concentrations of circulating glucocorticoids at the early stages of inflammation results in downregulation of inflammatory responses. Oestrogens markedly reduce the response to injury in a variety of experimental models. Glucagon and thyroid hormones exert indirect anti-inflammatory effects mediated by the activity of the adrenal cortex. Accordingly, inflammation is not only merely a local response, but a hormone-controlled process. PMID:18475521

  20. Quantitative Phosphoproteomics Revealed Glucose-Stimulated Responses of Islet Associated with Insulin Secretion.

    PubMed

    Li, Jiaming; Li, Qingrun; Tang, Jiashu; Xia, Fangying; Wu, Jiarui; Zeng, Rong

    2015-11-01

    As central tissue of glucose homeostasis, islet has been an important focus of diabetes research. Phosphorylation plays pivotal roles in islet function, especially in islet glucose-stimulated insulin secretion. A systematic view on how phosphorylation networks were coordinately regulated in this process remains lacking, partially due to the limited amount of islets from an individual for a phosphoproteomic analysis. Here we optimized the in-tip and best-ratio phosphopeptide enrichment strategy and a SILAC-based workflow for processing rat islet samples. With limited islet lysates from each individual rat (20-47 μg), we identified 8539 phosphosites on 2487 proteins. Subsequent quantitative analyses uncovered that short-term (30 min) high glucose stimulation induced coordinate responses of islet phosphoproteome on multiple biological levels, including insulin secretion related pathways, cytoskeleton dynamics, protein processing in ER and Golgi, transcription and translation, and so on. Furthermore, three glucose-responsive phosphosites (Prkar1a pT75pS77 and Tagln2 pS163) from the data set were proved to be correlated with insulin secretion. Overall, we initially gave an in-depth map of islet phosphoproteome regulated by glucose on individual rat level. This was a significant addition to our knowledge about how phosphorylation networks responded in insulin secretion. Also, the list of changed phosphosites was a valuable resource for molecular researchers in diabetes field. PMID:26437020

  1. The effect of hypophysectomy on pancreatic islet hormone and insulin-like growth factor I content and mRNA expression in rat.

    PubMed

    Jevdjovic, Tanja; Maake, Caroline; Zwimpfer, Cornelia; Krey, Gunthild; Eppler, Elisabeth; Zapf, Jürgen; Reinecke, Manfred

    2005-02-01

    hypophysectomy is accompanied by a decrease in pancreatic IGF-I peptide and mRNA but by partly discordant changes in the serum concentrations of insulin and glucagon and the islet peptide and/or mRNA content of the three major islet hormones. It appears that GH deficiency resulting in a "low IGF-I state" affects translational efficiency of these hormones as well as their secretory responses. The maintenance of normoglycemia in the presence of reduced insulin and elevated glucagon serum levels, both of which would be expected to raise blood glucose, may result mainly from the enhanced insulin sensitivity, possibly due to GH deficiency and the subsequent decrease in IGF-I production. PMID:15812646

  2. Islet Autoantibodies.

    PubMed

    Lampasona, Vito; Liberati, Daniela

    2016-06-01

    Islet autoantibodies are the main markers of pancreatic autoimmunity in type 1 diabetes (T1D). Islet autoantibodies recognize insulin (IAA), glutamic acid decarboxylase (GADA), protein phosphatase-like IA-2 (IA-2A), and ZnT8 (ZnT8A), all antigens that are found on secretory granules within pancreatic beta cells. Islet antibodies, measured by sensitive and specific liquid phase assays, are the key parameters of the autoimmune response monitored for diagnostics or prognostics in patients with T1D or for disease prediction in at-risk individuals before T1D onset. Islet autoantibodies have been the main tool used to explore the natural history of T1D; this review summarizes the current knowledge about the autoantigens and the phenotype of islets autoantibodies acquired in large prospective studies from birth in children at risk of developing T1D. PMID:27112957

  3. Assessment of Islet Function Following Islet and Pancreas Transplantation

    PubMed Central

    Dy, Emily C.; Harlan, David M.; Rother, Kristina I.

    2014-01-01

    Pancreas and islet transplant recipients are monitored using various metabolic and imaging methods. The inaccessibility of the transplanted whole pancreas and of the isolated islets poses specific problems (eg, all assessment techniques are indirect). Although successful pancreas transplantation typically restores normal glucose homeostasis, islet transplantation into the liver does not completely normalize islet hormone secretion and glucose metabolism. Development of better testing strategies, such as direct islet imaging, will significantly advance the field. PMID:16879785

  4. Modulation of pancreatic islets-stress axis by hypothalamic releasing hormones and 11β-hydroxysteroid dehydrogenase

    PubMed Central

    Schmid, Janine; Ludwig, Barbara; Schally, Andrew V.; Steffen, Anja; Ziegler, Christian G.; Block, Norman L.; Koutmani, Yassemi; Brendel, Mathias D.; Karalis, Katia P.; Simeonovic, Charmaine J.; Licinio, Julio; Ehrhart-Bornstein, Monika; Bornstein, Stefan R.

    2011-01-01

    Corticotropin-releasing hormone (CRH) and growth hormone-releasing hormone (GHRH), primarily characterized as neuroregulators of the hypothalamic-pituitary-adrenal axis, directly influence tissue-specific receptor-systems for CRH and GHRH in the endocrine pancreas. Here, we demonstrate the expression of mRNA for CRH and CRH-receptor type 1 (CRHR1) and of protein for CRHR1 in rat and human pancreatic islets and rat insulinoma cells. Activation of CRHR1 and GHRH-receptor significantly increased cell proliferation and reduced cell apoptosis. CRH stimulated both cellular content and release of insulin in rat islet and insulinoma cells. At the ultrastructural level, CRHR1 stimulation revealed a more active metabolic state with enlarged mitochondria. Moreover, glucocorticoids that promote glucose production are balanced by both 11b-hydroxysteroid dehydrogenase (11β-HSD) isoforms; 11β-HSD–type-1 and 11β-HSD–type-2. We demonstrated expression of mRNA for 11β-HSD-1 and 11β-HSD-2 and protein for 11β-HSD-1 in rat and human pancreatic islets and insulinoma cells. Quantitative real-time PCR revealed that stimulation of CRHR1 and GHRH-receptor affects the metabolism of insulinoma cells by down-regulating 11β-HSD-1 and up-regulating 11β-HSD-2. The 11β-HSD enzyme activity was analyzed by measuring the production of cortisol from cortisone. Similarly, activation of CRHR1 resulted in reduced cortisol levels, indicating either decreased 11β-HSD-1 enzyme activity or increased 11β-HSD-2 enzyme activity; thus, activation of CRHR1 alters the glucocorticoid balance toward the inactive form. These data indicate that functional receptor systems for hypothalamic-releasing hormone agonists exist within the endocrine pancreas and influence synthesis of insulin and the pancreatic glucocorticoid shuttle. Agonists of CRHR1 and GHRH-receptor, therefore, may play an important role as novel therapeutic tools in the treatment of diabetes mellitus. PMID:21825133

  5. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lep{sup ob/ob} mice

    SciTech Connect

    Sekiya, Motohiro; Yahagi, Naoya; Tamura, Yoshiaki; Okazaki, Hiroaki; Igarashi, Masaki; Ohta, Keisuke; Takanashi, Mikio; Kumagai, Masayoshi; Takase, Satoru; Nishi, Makiko; Takeuchi, Yoshinori; Izumida, Yoshihiko; Kubota, Midori; Ohashi, Ken; Iizuka, Yoko; Yagyu, Hiroaki; Gotoda, Takanari; Nagai, Ryozo; Shimano, Hitoshi; Yamada, Nobuhiro; and others

    2009-09-25

    It has long been a matter of debate whether the hormone-sensitive lipase (HSL)-mediated lipolysis in pancreatic {beta}-cells can affect insulin secretion through the alteration of lipotoxicity. We generated mice lacking both leptin and HSL (Lep{sup ob/ob}/HSL{sup -/-}) and explored the role of HSL in pancreatic {beta}-cells in the setting of obesity. Lep{sup ob/ob}/HSL{sup -/-} developed elevated blood glucose levels and reduced plasma insulin levels compared with Lep{sup ob/ob}/HSL{sup +/+} in a fed state, while the deficiency of HSL did not affect glucose homeostasis in Lep{sup +/+} background. The deficiency of HSL exacerbated the accumulation of triglycerides in Lep{sup ob/ob} islets, leading to reduced glucose-stimulated insulin secretion. The deficiency of HSL also diminished the islet mass in Lep{sup ob/ob} mice due to decreased cell proliferation. In conclusion, HSL affects insulin secretary capacity especially in the setting of obesity.

  6. Transcriptional Regulation of the Pancreatic Islet: Implications for Islet Function

    PubMed Central

    Stitzel, Michael L.; Kycia, Ina; Kursawe, Romy; Ucar, Duygu

    2015-01-01

    Islets of Langerhans contain multiple hormone-producing endocrine cells controlling glucose homeostasis. Transcription establishes and maintains islet cellular fates and identities. Genetic and environmental disruption of islet transcription triggers cellular dysfunction and disease. Early transcriptional regulation studies of specific islet genes, including insulin (INS) and the transcription factor PDX1, identified the first cis-regulatory DNA sequences and trans-acting factors governing islet function. Here, we review how human islet “omics” studies are reshaping our understanding of transcriptional regulation in islet (dys)function and diabetes. First, we highlight the expansion of islet transcript number, form, and function and of DNA transcriptional regulatory elements controlling their production. Next, we cover islet transcriptional effects of genetic and environmental perturbation. Finally, we discuss how these studies’ emerging insights should empower our diabetes research community to build mechanistic understanding of diabetes pathophysiology and to equip clinicians with tailored, precision medicine options to prevent and treat islet dysfunction and diabetes. PMID:26272056

  7. Immune responses to an encapsulated allogeneic islet {beta}-cell line in diabetic NOD mice

    SciTech Connect

    Black, Sasha P. . E-mail: Sasha.Black@ca.crl.com; Constantinidis, Ioannis; Cui, Hong; Tucker-Burden, Carol; Weber, Collin J.; Safley, Susan A.

    2006-02-03

    Our goal is to develop effective islet grafts for treating type 1 diabetes. Since human islets are scarce, we evaluated the efficacy of a microencapsulated insulin-secreting conditionally transformed allogeneic {beta}-cell line ({beta}TC-tet) in non-obese diabetic mice treated with tetracycline to inhibit cell growth. Relatively low serum levels of tetracycline controlled proliferation of {beta}TC-tet cells without inhibiting effective control of hyperglycemia in recipients. There was no significant host cellular reaction to the allografts or host cell adherence to microcapsules, and host cytokine levels were similar to those of sham-operated controls. We conclude that encapsulated allogeneic {beta}-cell lines may be clinically relevant, because they effectively restore euglycemia and do not elicit a strong cellular immune response following transplantation. To our knowledge, this is First extensive characterization of the kinetics of host cellular and cytokine responses to an encapsulated islet cell line in an animal model of type 1 diabetes.

  8. Free fatty acids induce a proinflammatory response in islets via the abundantly expressed interleukin-1 receptor I.

    PubMed

    Böni-Schnetzler, Marianne; Boller, Simone; Debray, Sarah; Bouzakri, Karim; Meier, Daniel T; Prazak, Richard; Kerr-Conte, Julie; Pattou, Francois; Ehses, Jan A; Schuit, Frans C; Donath, Marc Y

    2009-12-01

    Islets of patients with type 2 diabetes mellitus (T2DM) display features of an inflammatory process including elevated levels of the cytokine IL-1beta, various chemokines, and macrophages. IL-1beta is a master regulator of inflammation, and IL-1 receptor type I (IL-1RI) blockage improves glycemia and insulin secretion in humans with T2DM and in high-fat-fed mice pointing to a pivotal role of IL-1RI activity in intra-islet inflammation. Given the association of dyslipidemia and T2DM, we tested whether free fatty acids (FFA) promote the expression of proinflammatory factors in human and mouse islets and investigated a role for the IL-1RI in this response. A comparison of 22 mouse tissues revealed the highest IL-1RI expression levels in islets and MIN6 beta-cells. FFA induced IL-1beta, IL-6, and IL-8 in human islets and IL-1beta and KC in mouse islets. Elevated glucose concentrations enhanced FFA-induced proinflammatory factors in human islets. Blocking the IL-1RI with the IL-1R antagonist (IL-1Ra) strongly inhibited FFA-mediated expression of proinflammatory factors in human and mouse islets. Antibody inhibition of IL-1beta revealed that FFA stimulated IL-1RI activity via the induction of the receptor ligand. FFA-induced IL-1beta and KC expression in mouse islets was completely dependent on the IL-1R/Toll-like receptor (TLR) docking protein Myd88 and partly dependent on TLR2 and -4. Activation of TLR2 in purified human beta-cells and islets stimulated the expression of proinflammatory factors, and IL-1RI activity increased the TLR2 response in human islets. We conclude that FFA and TLR stimulation induce proinflammatory factors in islets and that IL-1RI engagement results in signal amplification. PMID:19819943

  9. Ionic and secretory response of pancreatic islet cells to minoxidil sulfate

    SciTech Connect

    Antoine, M.H.; Hermann, M.; Herchuelz, A.; Lebrun, P. )

    1991-07-01

    Minoxidil sulfate is an antihypertensive agent belonging to the new class of vasodilators, the K+ channel openers. The present study was undertaken to characterize the effects of minoxidil sulfate on ionic and secretory events in rat pancreatic islets. The drug unexpectedly provoked a concentration-dependent decrease in 86Rb outflow. This inhibitory effect was reduced in a concentration-dependent manner by glucose and tolbutamide. Minoxidil sulfate did not affect 45Ca outflow from islets perfused in the presence of extracellular Ca++ and absence or presence of glucose. However, in islets exposed to a medium deprived of extracellular Ca++, the drug provoked a rise in 45Ca outflow. Whether in the absence or presence of extracellular Ca++, minoxidil sulfate increased the cytosolic free Ca++ concentration of islet cells. Lastly, minoxidil sulfate increased the release of insulin from glucose-stimulated pancreatic islets. These results suggest that minoxidil sulfate reduces the activity of the ATP-sensitive K+ channels and promotes an intracellular translocation of Ca++. The latter change might account for the effect of the drug on the insulin-releasing process. However, the secretory response to minoxidil sulfate could also be mediated, at least in part, by a modest Ca++ entry.

  10. Hormonal component of tumor photodynamic therapy response

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen; Merchant, Soroush

    2008-02-01

    The involvement of adrenal glucocorticoid hormones in the response of the treatment of solid tumors by photodynamic therapy (PDT) comes from the induction of acute phase response by this modality. This adrenal gland activity is orchestrated through the engagement of the hypothalamic-pituitary-adrenal hormonal axis incited by stress signals emanating from the PDT-treated tumor. Glucocorticoid hormone activity engendered within the context of PDT-induced acute phase response performs multiple important functions; among other involvements they beget acute phase reactant production, systemic neutrophil mobilization, and control the production of inflammation-modulating and immunoregulatory proteins.

  11. Direct visualisation of peptide hormones in cultured pancreatic islet alpha- and beta-cells by intact-cell mass spectrometry.

    PubMed

    Buchanan, Christina M; Malik, Arpita S; Cooper, Garth J S

    2007-01-01

    The application of intact-cell mass spectrometry (ICM) by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry to achieve direct protein-profiling of bacterial species is now well established. However, this methodology has not to our knowledge been applied to the analysis of mammalian cells in routine culture. Here, we describe a novel application of ICM by which we have identified proteins in intact cells from two lines representative of pancreatic islet alpha- and beta-cells. Adherent alphaTC1 clone 9 and betaTC6 F7 cells were harvested into phosphate-buffered saline (PBS) using enzyme-free dissociation buffer before 1 microL of cell suspension was spotted onto MALDI plates. Cells were overlaid with sinapinic acid then washed with pure water before application of a final coat of sinapinic acid. Data in the 2000-20,000 m/z range were acquired in linear mode on a Voyager DE-Pro mass spectrometer. The proteins which ionised were composed in large part of peptide hormones (e.g. insulin and glucagon) known to be packaged into the secretory granules of the beta- and alpha-cells respectively. However, in addition to visualising the peptides expected to be associated with these cells, a mass consistent with oxyntomodulin was identified in the cultured alpha-cells, a finding not previously reported to our knowledge. In summary, this paper describes, for the first time, a rapid and direct method useful for identifying secretory products in intact endocrine cells. PMID:17918213

  12. Islet and Stem Cell Encapsulation for Clinical Transplantation

    PubMed Central

    Krishnan, Rahul; Alexander, Michael; Robles, Lourdes; Foster 3rd, Clarence E.; Lakey, Jonathan R.T.

    2014-01-01

    Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues. PMID:25148368

  13. Islet and stem cell encapsulation for clinical transplantation.

    PubMed

    Krishnan, Rahul; Alexander, Michael; Robles, Lourdes; Foster, Clarence E; Lakey, Jonathan R T

    2014-01-01

    Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues. PMID:25148368

  14. Rhesus monkeys and baboons develop FVIII inhibitors in response to porcine endothelial cells or islets

    PubMed Central

    Stewart, JM; Tarantal, AF; Hawthorne, WJ; Salvaris, EJ; O’Connell, PJ; Nottle, MB; d’Apice, AJF; Cowan, PJ; Kearns-Jonker, M

    2014-01-01

    Background Xenotransplantation of porcine organs holds promise of solving the human organ donor shortage. The use of α-1,3-galactosyltransferase knockout (GTKO) pig donors mitigates hyperacute rejection, while delayed rejection is currently precipitated by potent immune and hemostatic complications. Previous analysis by our laboratory suggests FVIII inhibitors might be elicited by the structurally restricted xenoantibody response which occurs after transplantation of either pig GTKO/hCD55/hCD59/hHT transgenic neonatal islet cell clusters or GTKO endothelial cells. Methods A recombinant xenoantibody was generated using sequences from baboons demonstrating an active xenoantibody response at day 28 after GTKO/hCD55/hCD59/hHT transgenic pig neonatal islet cell cluster transplantation. Rhesus monkeys were immunized with GTKO pig endothelial cells to stimulate an anti-nonGal xenoantibody response. Serum was collected at day 0 and 7 after immunization. A two stage chromogenic assay was used to measure FVIII cofactor activity and identify antibodies which inhibit FVIII function. Molecular modeling and molecular dynamics simulations were used to predict antibody structure and the residues which contribute to antibody-FVIII interactions. Competition ELISA was used to verify predictions at the domain structural level. Results Antibodies which inhibit recombinant human FVIII function are elicited after non-human primates are transplanted with either GTKO pig neonatal islet cell clusters or endothelial cells. There is an apparent increase of inhibitor titer by 15 Bethesda units after transplant; where an increase greater than 5 Bu can indicate pathology in humans. Furthermore, competition ELISA verifies the computer modeled prediction that the recombinant xenoantibody, H66K12, binds the C1 domain of FVIII. Conclusions The development of FVIII inhibitors is a novel illustration of the potential impact the humoral immune response can have on coagulative dysfunction in

  15. Responses against islet antigens in NOD mice are prevented by tolerance to proinsulin but not IGRP.

    PubMed

    Krishnamurthy, Balasubramanian; Dudek, Nadine L; McKenzie, Mark D; Purcell, Anthony W; Brooks, Andrew G; Gellert, Shane; Colman, Peter G; Harrison, Leonard C; Lew, Andrew M; Thomas, Helen E; Kay, Thomas W H

    2006-12-01

    Type 1 diabetes (T1D) is characterized by immune responses against several autoantigens expressed in pancreatic beta cells. T cells specific for proinsulin and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) can induce T1D in NOD mice. However, whether immune responses to multiple autoantigens are caused by spreading from one to another or whether they develop independently of each other is unknown. As cytotoxic T cells specific for IGRP were not detected in transgenic NOD mice tolerant to proinsulin, we determined that immune responses against proinsulin are necessary for IGRP-specific T cells to develop. On the other hand, transgenic overexpression of IGRP resulted in loss of intra-islet IGRP-specific T cells but did not protect NOD mice from insulitis or T1D, providing direct evidence that the response against IGRP is downstream of the response to proinsulin. Our results suggest that pathogenic proinsulin-specific immunity in NOD mice subsequently spreads to other antigens such as IGRP. PMID:17143333

  16. Responses against islet antigens in NOD mice are prevented by tolerance to proinsulin but not IGRP

    PubMed Central

    Krishnamurthy, Balasubramanian; Dudek, Nadine L.; McKenzie, Mark D.; Purcell, Anthony W.; Brooks, Andrew G.; Gellert, Shane; Colman, Peter G.; Harrison, Leonard C.; Lew, Andrew M.; Thomas, Helen E.; Kay, Thomas W.H.

    2006-01-01

    Type 1 diabetes (T1D) is characterized by immune responses against several autoantigens expressed in pancreatic β cells. T cells specific for proinsulin and islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP) can induce T1D in NOD mice. However, whether immune responses to multiple autoantigens are caused by spreading from one to another or whether they develop independently of each other is unknown. As cytotoxic T cells specific for IGRP were not detected in transgenic NOD mice tolerant to proinsulin, we determined that immune responses against proinsulin are necessary for IGRP-specific T cells to develop. On the other hand, transgenic overexpression of IGRP resulted in loss of intra-islet IGRP-specific T cells but did not protect NOD mice from insulitis or T1D, providing direct evidence that the response against IGRP is downstream of the response to proinsulin. Our results suggest that pathogenic proinsulin-specific immunity in NOD mice subsequently spreads to other antigens such as IGRP. PMID:17143333

  17. PDX-1 haploinsufficiency limits the compensatory islet hyperplasia that occurs in response to insulin resistance

    PubMed Central

    Kulkarni, Rohit N.; Jhala, Ulupi S.; Winnay, Jonathon N.; Krajewski, Stan; Montminy, Marc; Kahn, C. Ronald

    2004-01-01

    Inadequate compensatory β cell hyperplasia in insulin-resistant states triggers the development of overt diabetes. The mechanisms that underlie this crucial adaptive response are not fully defined. Here we show that the compensatory islet-growth response to insulin resistance in 2 models — insulin receptor (IR)/IR substrate–1 (IRS-1) double heterozygous mice and liver-specific IR KO (LIRKO) mice — is severely restricted by PDX-1 heterozygosity. Six-month-old IR/IRS-1 and LIRKO mice both showed up to a 10-fold increase in β cell mass, which involved epithelial-to-mesenchymal transition. In both models, superimposition of PDX-1 haploinsufficiency upon the background of insulin resistance completely abrogated the adaptive islet hyperplastic response, and instead the β cells showed apoptosis resulting in premature death of the mice. This study shows that, in postdevelopmental states of β cell growth, PDX-1 is a critical regulator of β cell replication and is required for the compensatory response to insulin resistance. PMID:15372107

  18. Unraveling pancreatic islet biology by quantitative proteomics

    SciTech Connect

    Zhou, Jianying; Dann, Geoffrey P.; Liew, Chong W.; Smith, Richard D.; Kulkarni, Rohit N.; Qian, Weijun

    2011-08-01

    The pancreatic islets of Langerhans play a critical role in maintaining blood glucose homeostasis by secreting insulin and several other important peptide hormones. Impaired insulin secretion due to islet dysfunction is linked to the pathogenesis underlying both Type 1 and Type 2 diabetes. Over the past 5 years, emerging proteomic technologies have been applied to dissect the signaling pathways that regulate islet functions and gain an understanding of the mechanisms of islet dysfunction relevant to diabetes. Herein, we briefly review some of the recent quantitative proteomic studies involving pancreatic islets geared towards gaining a better understanding of islet biology relevant to metabolic diseases.

  19. Immune responses against islet allografts during tapering of immunosuppression - A pilot study in 5 subjects.

    PubMed

    Huurman, Volkert A L; van der Torren, Cornelis R; Gillard, Pieter; Hilbrands, Robert; van der Meer-Prins, Ellen P M W; Duinkerken, Gaby; Gorus, Frans K; Claas, Frans H J; Keymeulen, Bart; Roelen, Dave L; Pipeleers, Daniel G; Roep, Bart O

    2012-04-25

    Transplantation of isolated islet of Langerhans cells has great potential as a cure for type 1 diabetes but continuous immune suppressive therapy often causes considerable side effects. Tapering of immunosuppression in successfully transplanted patients would lower patients' health risk. To identify immune biomarkers that may prove informative in monitoring tapering, we studied the effect of tapering on islet auto- and alloimmune reactivity in a pilot study in five transplant recipients in vitro. Cytokine responses to the graft were measured using Luminex technology. Avidity of alloreactive cytotoxic T Lymphocytes (CTL) was determined by CD8 blockade. The influence of immunosuppression was mimicked by in vitro replenishment of tacrolimus and MPA, the active metabolite of mycophenolate mofetil. Tapering of tacrolimus was generally followed by decreased C-peptide production. T-cell autoreactivity increased in four out of five patients during tapering. Overall alloreactive CTL precursor frequencies did not change, but their avidity to donor mismatches increased significantly after tapering (p=0.035). In vitro addition of tacrolimus but not MPA strongly inhibited CTL alloreactivity during tapering and led to a significant shift to anti-inflammatory graft-specific cytokine production. Tapering of immunosuppression is characterized by diverse immune profiles that appear to relate inversely to plasma C-peptide levels. Highly avid allospecific CTLs that are known to associate with rejection increased during tapering, but could be countered by restoring immune suppression in vitro. Immune monitoring studies may help guiding tapering of immunosuppression after islet cell transplantation, even though we do not have formal prove yet that the observed changes reflect direct effects of immune suppression on immunity. © 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology. PMID:23607493

  20. Immune responses against islet allografts during tapering of immunosuppression--a pilot study in 5 subjects.

    PubMed

    Huurman, V A L; van der Torren, C R; Gillard, P; Hilbrands, R; van der Meer-Prins, E P M W; Duinkerken, G; Gorus, F K; Claas, F H J; Keymeulen, B; Roelen, D L; Pipeleers, D G; Roep, B O

    2012-08-01

    Transplantation of isolated islet of Langerhans cells has great potential as a cure for type 1 diabetes but continuous immune suppressive therapy often causes considerable side effects. Tapering of immunosuppression in successfully transplanted patients would lower patients' health risk. To identify immune biomarkers that may prove informative in monitoring tapering, we studied the effect of tapering on islet auto- and alloimmune reactivity in a pilot study in five transplant recipients in vitro. Cytokine responses to the graft were measured using Luminex technology. Avidity of alloreactive cytotoxic T Lymphocytes (CTL) was determined by CD8 blockade. The influence of immunosuppression was mimicked by in vitro replenishment of tacrolimus and MPA, the active metabolite of mycophenolate mofetil. Tapering of tacrolimus was generally followed by decreased C-peptide production. T-cell autoreactivity increased in four out of five patients during tapering. Overall alloreactive CTL precursor frequencies did not change, but their avidity to donor mismatches increased significantly after tapering (P = 0·035). In vitro addition of tacrolimus but not MPA strongly inhibited CTL alloreactivity during tapering and led to a significant shift to anti-inflammatory graft-specific cytokine production. Tapering of immunosuppression is characterized by diverse immune profiles that appear to relate inversely to plasma C-peptide levels. Highly avid allospecific CTLs that are known to associate with rejection increased during tapering, but could be countered by restoring immune suppression in vitro. Immune monitoring studies may help guiding tapering of immunosuppression after islet cell transplantation, even though we do not have formal prove yet that the observed changes reflect direct effects of immune suppression on immunity. PMID:22774994

  1. Light scattering as an intrinsic indicator for pancreatic islet cell mass and secretion.

    PubMed

    Ilegems, E; van Krieken, P P; Edlund, P K; Dicker, A; Alanentalo, T; Eriksson, M; Mandic, S; Ahlgren, U; Berggren, P-O

    2015-01-01

    The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulation and thereby to the development of diabetes. It is therefore necessary to develop tools for the assessment of both pancreatic islet mass and function, with the aim of understanding cellular regulatory mechanisms and factors guiding islet plasticity. Although most of the existing techniques rely on the use of artificial indicators, we present an imaging methodology based on intrinsic optical properties originating from mature insulin secretory granules within endocrine cells that reveals both pancreatic islet mass and function. We demonstrate the advantage of using this imaging strategy by monitoring in vivo scattering signal from pancreatic islets engrafted into the anterior chamber of the mouse eye, and how this versatile and noninvasive methodology permits the characterization of islet morphology and plasticity as well as hormone secretory status. PMID:26030284

  2. Pancreatic islet blood flow and its measurement.

    PubMed

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  3. Pancreatic islet blood flow and its measurement

    PubMed Central

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-01-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  4. Hormonal responses in strenuous jumping effort.

    PubMed

    Bosco, C; Tihanyl, J; Rivalta, L; Parlato, G; Tranquilli, C; Pulvirenti, G; Foti, C; Viru, M; Viru, A

    1996-02-01

    In order to test the possibility for rapid responses of blood hormone levels in short-term supramaximal exercises, serum concentrations of corticotropin (ACTH), cortisol (C), total testosterone (tT), free testosterone (fT), growth hormone (GH), thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), prolactin (PRL), insulin-like growth factor (IGF-I), and sex hormone-binding globulin (SHBG) were determined by RIA procedures in blood samples obtained before and immediately after a 60-s period of consecutive vertical jumps (Bosco test). The study subjects were 16 Italian professional soccer players. Immediately after exercise, significant increases (p < 0.05) were found in the concentrations of ACTH (by 39%), C (by 14%), TSH (by 20%), fT3 (by 28%), fT4 (by 30%), tT (by 12%), fT (by 13%), and SHBG (by 21%). Significant changes were not detected in the blood levels of GH, IGF-I and PRL. Most pronounced testosterone responses were typical for persons of high jumping performance (the increase of serum tT correlated with average power output, r = 0.61 and jumping height, r = 0.66). The larger the drop in power output during 60-s jumping, the higher was the thyroid response: the difference in jumping height between the first and last 15-s period correlated with increases in TSH (r = 0.52) and in fT4, (r = 0.55). In conclusion, the obtained results indicate that in intense exercise, causing the rapid development of fatigue, rapid increases in serum levels of hormones of the pituitary-adrenocortical, pituitary-gonadal and pituitary-thyroid systems occur. PMID:8743723

  5. Islet-Specific T-Cell Responses and Proinflammatory Monocytes Define Subtypes of Autoantibody-Negative Ketosis-Prone Diabetes

    PubMed Central

    Brooks-Worrell, Barbara M.; Iyer, Dinakar; Coraza, Ivonne; Hampe, Christiane S.; Nalini, Ramaswami; Ozer, Kerem; Narla, Radhika; Palmer, Jerry P.; Balasubramanyam, Ashok

    2013-01-01

    OBJECTIVE Ketosis-prone diabetes (KPD) is characterized by diabetic ketoacidosis (DKA) in patients lacking typical features of type 1 diabetes. A validated classification scheme for KPD includes two autoantibody-negative (“A−”) phenotypic forms: “A−β−” (lean, early onset, lacking β-cell functional reserve) and “A−β+” (obese, late onset, with substantial β-cell functional reserve after the index episode of DKA). Recent longitudinal analysis of a large KPD cohort revealed that the A−β+ phenotype includes two distinct subtypes distinguished by the index DKA episode having a defined precipitant (“provoked,” with progressive β-cell function loss over time) or no precipitant (“unprovoked,” with sustained β-cell functional reserve). These three A− KPD subtypes are characterized by absence of humoral islet autoimmune markers, but a role for cellular islet autoimmunity is unknown. RESEARCH DESIGN AND METHODS Islet-specific T-cell responses and the percentage of proinflammatory (CD14+CD16+) blood monocytes were measured in A−β− (n = 7), provoked A−β+ (n = 15), and unprovoked A−β+ (n = 13) KPD patients. Genotyping was performed for type 1 diabetes–associated HLA class II alleles. RESULTS Provoked A−β+ and A−β− KPD patients manifested stronger islet-specific T-cell responses (P < 0.03) and higher percentages of proinflammatory CD14+CD16+ monocytes (P < 0.01) than unprovoked A−β+ KPD patients. A significant relationship between type 1 diabetes HLA class II protective alleles and negative T-cell responses was observed. CONCLUSIONS Provoked A−β+ KPD and A−β− KPD are associated with a high frequency of cellular islet autoimmunity and proinflammatory monocyte populations. In contrast, unprovoked A−β+ KPD lacks both humoral and cellular islet autoimmunity. PMID:24130366

  6. Physical exercise introduced after weaning enhances pancreatic islet responsiveness to glucose and potentiating agents in adult MSG-obese rats.

    PubMed

    Ribeiro, R A; Bonfleur, M L; Vanzela, E C; Zotti, A I; Scomparin, D X; Boschero, A C; Balbo, S L

    2014-08-01

    Physical exercise represents an alternative way to prevent and/or ameliorate chronic metabolic diseases. Disruption of sympathetic nervous system (SNS) activity contributes to adiposity in obese subjects. Here, we verified the preventive effect of swimming training upon adiposity, adrenal catecholamine storage, and pancreatic islet function in obese monosodium glutamate (MSG)-treated rats. Male neonatal Wistar rats received MSG (4 mg/g body weight) during the first 5 days of life and, at weaning, half of the rats were submitted to swimming training, 30 min/day, 3 days a week, until 90 days of age (exercised rats: MSGex). Half of the rats were used as controls (sedentary group, MSGsd). Exercise training (ET) decreased insulinemia and fat deposition in MSGex, and increased adrenal catecholamine content, compared with MSGsd rats. Insulinemia during the ivGTT was lower in MSGex rats, despite a lack of difference in glycemia. Swimming training enhanced insulin release in islets challenged by 2.8-8.3 mmol/l glucose, whereas, at supraphysiological glucose concentrations (11.1-16.7 mmol/l), MSGex islets secreted less insulin than MSGsd. No differences in insulin secretion were observed following l-arginine (Arg) or K(+) stimuli. In contrast, islets from MSGex rats secreted more insulin when exposed to carbachol (100 μmol/l), forskolin (10 μmol/l), or IBMX (1 mmol/l) at 8.3 mmol/l glucose. Additionally, MSGex islets presented a better epinephrine inhibition upon insulin release. These results demonstrate that ET prevented the onset of obesity in MSG rats, probably by enhancing adrenal catecholamine levels. ET ameliorates islet responsiveness to several compounds, as well as insulin peripheral action. PMID:24554535

  7. Estrogen mediation of hormone responses to exercise.

    PubMed

    Kraemer, Robert R; Francois, Michelle; Castracane, V Daniel

    2012-10-01

    The roles of estrogens extend from the regulation of reproduction to other functions involved in control of metabolism, fluid balance, as well as gastrointestinal, lung, and brain function, with a strong effect on other hormones that subsequently alter the physiology of multiple tissues. As such, alteration of endogenous estrogens across the menstrual cycle, or from oral contraception and estrogen replacement therapy, can affect these tissues. Due to the important effects that estrogens have on different tissues, there are many investigations concerning the effects of a human estrogenic environment on endocrine responses to exercise. The following review will describe the consequences of varying estrogen levels on pituitary, adrenal, gonadal, and endocrine function, followed by discussion of the outcomes of different estrogen levels on endocrine tissues in response to exercise, problems encountered for interpretation of findings, and recommended direction for future research. PMID:22512823

  8. Microfluidic glucose stimulation reveals limited coordination of intracellular Ca2+ activity oscillations in pancreatic islets

    PubMed Central

    Rocheleau, Jonathan V.; Walker, Glenn M.; Head, W. Steven; McGuinness, Owen P.; Piston, David W.

    2004-01-01

    The pancreatic islet is a functional microorgan involved in maintaining normoglycemia through regulated secretion of insulin and other hormones. Extracellular glucose stimulates insulin secretion from islet β cells through an increase in redox state, which can be measured by NAD(P)H autofluorescence. Glucose concentrations over ≈7 mM generate synchronous oscillations in β cell intracellular Ca2+ concentration ([Ca2+]i), which lead to pulsatile insulin secretion. Prevailing models assume that the pancreatic islet acts as a functional syncytium, and the whole islet [Ca2+]i response has been modeled in terms of islet bursting and pacemaker models. To test these models, we developed a microfluidic device capable of partially stimulating an islet, while allowing observation of the NAD(P)H and [Ca2+]i responses. We show that β cell [Ca2+]i oscillations occur only within regions stimulated with more than ≈6.6 mM glucose. Furthermore, we show that tolbutamide, an antagonist of the ATP-sensitive K+ channel, allows these oscillations to travel farther into the nonstimulated regions of the islet. Our approach shows that the extent of Ca2+ propagation across the islet depends on a delicate interaction between the degree of coupling and the extent of ATP-sensitive K+-channel activation and illustrates an experimental paradigm that will have utility for many other biological systems. PMID:15317941

  9. Combined hormonal infusion simulates the metabolic response to injury.

    PubMed Central

    Bessey, P Q; Watters, J M; Aoki, T T; Wilmore, D W

    1984-01-01

    To investigate the role of hormones as mediators of the metabolic response to injury, nine normal male volunteers received a continuous 74-hour infusion of the three 'stress' hormones: cortisol, glucagon, and epinephrine. As a control, each subject received a saline infusion during another 4-day period. Diets were constant and matched on both occasions. Hormonal infusion achieved hormone concentrations similar to those seen following mild-moderate injury. With this alteration in the endocrine environment significant hypermetabolism, negative nitrogen and potassium balances, glucose intolerance, hyperinsulinemia, insulin resistance, sodium retention, and peripheral leukocytosis were observed. Additional studies with single hormone infusions indicated that these responses resulted from both additive and synergistic interactions of the hormones. Triple hormone infusion simulated many of the metabolic responses observed following mild-moderate injury and other catabolic illnesses. PMID:6431917

  10. [Sex Specificity in Age-Related Thyroid Hormone Responsiveness].

    PubMed

    Suzuki, Satoru

    2016-01-01

    Similar to other systems, the endocrine system is affected by aging. Thyroid hormone, the action of which is affected by many factors, has been shown to be associated with longevity. The most useful marker for assessment of the thyroid hormone action is the TSH level. Although age and sex are believed to modify the pituitary set point or response to the free thyroid hormone concentration, the precise age- and sex-dependent responses to thyroid hormone have yet to be reported. In this lecture, molecular aspects of resistance to thyroid hormone are initially overviewed. After presentation of the evidence that the TSH-thyroid hormone axis is evolutionarily modified, and that negative feedback mechanisms may start to play roles in homeostatic regulation at the time of delivery, the rationale of age-dependent thyroid hormone resistance is introduced. To assess the age- and sex-dependent resistance to thyroid hormone, the index is provided by the formula based on the relationship between thyroid hormone and TSH levels. The index is calculated by the results of thyroid function tests obtained from the two individual clinical groups. From the results, there were negative relationships between the free T3 resistance index and age in males of both groups, while there were no apparent relationships in females. These findings indicate that there is a male-specific response to thyroid hormone with aging. Furthermore, the specific features of the response may not be affected by environmental factors such as the presence of disorders or medical treatments. PMID:27192800

  11. Pancreatic islet transplantation

    PubMed Central

    Corrêa-Giannella, Maria Lúcia; Raposo do Amaral, Alexandre S

    2009-01-01

    Background No formulation of exogenous insulin available to date has yet been able to mimic the physiological nictemeral rhythms of this hormone, and despite all engineering advancements, the theoretical proposal of developing a mechanical replacement for pancreatic β cell still has not been reached. Thus, the replacement of β cells through pancreas and pancreatic islet transplantation are the only concrete alternatives for re-establishing the endogenous insulin secretion in type 1 diabetic patients. Since only 1 to 1.5% of the pancreatic mass corresponds to endocrine tissue, pancreatic islets transplantation arises as a natural alternative. Data from the International Islet Transplant Registry (ITR) from 1983 to December 2000 document a total of 493 transplants performed around the world, with progressively worse rates of post-transplant insulin independence. In 2000, the "Edmonton Protocol" introduced several modifications to the transplantation procedure, such as the use of a steroid-free immunosuppression regimen and transplantation of a mean islet mass of 11,000 islet equivalents per kilogram, which significantly improved 1-year outcomes. Although the results of a 5-year follow-up in 65 patients demonstrated improvement in glycemic instability in a significant portion of them, only 7.5% of the patients have reached insulin independence, indicating the need of further advances in the preservation of the function of transplanted islet. In addition to the scarcity of organs available for transplantation, islets transplantation still faces major challenges, specially those related to cell loss during the process of islet isolation and the losses related to the graft site, apoptosis, allorejection, autoimmunity, and immunosuppression. The main strategies to optimize islet transplantation aim at improving all these aspects. Conclusion Human islet transplantation should be regarded as an intervention that can decrease the frequency of severe hypoglycemic episodes

  12. Selection of polymers for application in scaffolds applicable for human pancreatic islet transplantation.

    PubMed

    Smink, Alexandra M; de Haan, Bart J; Paredes-Juarez, Genaro A; Wolters, Anouk H G; Kuipers, Jeroen; Giepmans, Ben N G; Schwab, Leendert; Engelse, Marten A; van Apeldoorn, Aart A; de Koning, Eelco; Faas, Marijke M; de Vos, Paul

    2016-01-01

    The liver is currently the site for transplantation of islets in humans. This is not optimal for islets, but alternative sites in humans are not available. Polymeric scaffolds in surgically accessible areas are a solution. As human donors are rare, the polymers should not interfere with functional survival of human-islets. We applied a novel platform to test the adequacy of polymers for application in scaffolds for human-islet transplantation. Viability, functionality, and immune parameters were included to test poly(D,L-lactide-co-ε-caprolactone) (PDLLCL), poly(ethylene oxide terephthalate)/polybutylene terephthalate (PEOT/PBT) block copolymer, and polysulfone. The type of polymer influenced the functional survival of human islets. In islets cultured on PDLLCL the glucagon-producing α-cells and insulin-producing β-cells contained more hormone granules than in islets in contact with PEOT/PBT or polysulfone. This was studied with ultrastructural analysis by electron microscopy (nanotomy) during 7 d of culture. PDLLCL was also associated with statistically significant lower release of double-stranded DNA (dsDNA, a so called danger-associate molecular pattern (DAMP)) from islets on PDLLCL when compared to the other polymers. DAMPs support undesired immune responses. Hydrophilicity of the polymers did not influence dsDNA release. Islets on PDLLCL also showed less cellular outgrowth. These outgrowing cells were mainly fibroblast and some β-cells undergoing epithelial to mesenchymal cell transition. None of the polymers influenced the glucose-stimulated insulin secretion. As PDLLCL was associated with less release of DAMPs, it is a promising candidate for creating a scaffold for human islets. Our study demonstrates that for sensitive, rare cadaveric donor tissue such as pancreatic islets it might be necessary to first select materials that do not influence functionality before proposing the biomaterial for in vivo application. Our presented platform may facilitate

  13. Enzyme Action in the Regulation of Plant Hormone Responses*

    PubMed Central

    Westfall, Corey S.; Muehler, Ashley M.; Jez, Joseph M.

    2013-01-01

    Plants synthesize a chemically diverse range of hormones that regulate growth, development, and responses to environmental stresses. The major classes of plant hormones are specialized metabolites with exquisitely tailored perception and signaling systems, but equally important are the enzymes that control the dose and exposure to the bioactive forms of these molecules. Here, we review new insights into the role of enzyme families, including the SABATH methyltransferases, the methylesterases, the GH3 acyl acid-amido synthetases, and the hormone peptidyl hydrolases, in controlling the biosynthesis and modifications of plant hormones and how these enzymes contribute to the network of chemical signals responsible for plant growth, development, and environmental adaptation. PMID:23709222

  14. Pancreatic islet plasticity: Interspecies comparison of islet architecture and composition

    PubMed Central

    Steiner, Donald J.; Kim, Abraham; Miller, Kevin; Hara, Manami

    2010-01-01

    The pancreatic islet displays diverse patterns of endocrine cell arrangement. The prototypic islet, with insulin-secreting β-cells forming the core surrounded by other endocrine cells in the periphery, is largely based on studies of normal rodent islets. Recent reports on large animals, including humans, show a difference in islet architecture, in which the endocrine cells are randomly distributed throughout the islet. This particular species difference has raised concerns regarding the interpretation of data based on rodent studies to humans. On the other hand, further variations have been reported in marsupials and some nonhuman primates, which possess an inverted ratio of β-cells to other endocrine cells. This review discusses the striking plasticity of islet architecture and cellular composition among various species including changes in response to metabolic states within a single species. We propose that this plasticity reflects evolutionary acquired adaptation induced by altered physiological conditions, rather than inherent disparities between species. PMID:20657742

  15. Prostaglandin E2 receptor, EP3, is induced in diabetic islets and negatively regulates glucose- and hormone-stimulated insulin secretion.

    PubMed

    Kimple, Michelle E; Keller, Mark P; Rabaglia, Mary R; Pasker, Renee L; Neuman, Joshua C; Truchan, Nathan A; Brar, Harpreet K; Attie, Alan D

    2013-06-01

    BTBR mice develop severe diabetes in response to genetically induced obesity due to a failure of the β-cells to compensate for peripheral insulin resistance. In analyzing BTBR islet gene expression patterns, we observed that Pgter3, the gene for the prostaglandin E receptor 3 (EP3), was upregulated with diabetes. The EP3 receptor is stimulated by prostaglandin E2 (PGE2) and couples to G-proteins of the Gi subfamily to decrease intracellular cAMP, blunting glucose-stimulated insulin secretion (GSIS). Also upregulated were several genes involved in the synthesis of PGE2. We hypothesized that increased signaling through EP3 might be coincident with the development of diabetes and contribute to β-cell dysfunction. We confirmed that the PGE2-to-EP3 signaling pathway was active in islets from confirmed diabetic BTBR mice and human cadaveric donors, with increased EP3 expression, PGE2 production, and function of EP3 agonists and antagonists to modulate cAMP production and GSIS. We also analyzed the impact of EP3 receptor activation on signaling through the glucagon-like peptide (GLP)-1 receptor. We demonstrated that EP3 agonists antagonize GLP-1 signaling, decreasing the maximal effect that GLP-1 can elicit on cAMP production and GSIS. Taken together, our results identify EP3 as a new therapeutic target for β-cell dysfunction in T2D. PMID:23349487

  16. Prostaglandin E2 Receptor, EP3, Is Induced in Diabetic Islets and Negatively Regulates Glucose- and Hormone-Stimulated Insulin Secretion

    PubMed Central

    Kimple, Michelle E.; Keller, Mark P.; Rabaglia, Mary R.; Pasker, Renee L.; Neuman, Joshua C.; Truchan, Nathan A.; Brar, Harpreet K.; Attie, Alan D.

    2013-01-01

    BTBR mice develop severe diabetes in response to genetically induced obesity due to a failure of the β-cells to compensate for peripheral insulin resistance. In analyzing BTBR islet gene expression patterns, we observed that Pgter3, the gene for the prostaglandin E receptor 3 (EP3), was upregulated with diabetes. The EP3 receptor is stimulated by prostaglandin E2 (PGE2) and couples to G-proteins of the Gi subfamily to decrease intracellular cAMP, blunting glucose-stimulated insulin secretion (GSIS). Also upregulated were several genes involved in the synthesis of PGE2. We hypothesized that increased signaling through EP3 might be coincident with the development of diabetes and contribute to β-cell dysfunction. We confirmed that the PGE2-to-EP3 signaling pathway was active in islets from confirmed diabetic BTBR mice and human cadaveric donors, with increased EP3 expression, PGE2 production, and function of EP3 agonists and antagonists to modulate cAMP production and GSIS. We also analyzed the impact of EP3 receptor activation on signaling through the glucagon-like peptide (GLP)-1 receptor. We demonstrated that EP3 agonists antagonize GLP-1 signaling, decreasing the maximal effect that GLP-1 can elicit on cAMP production and GSIS. Taken together, our results identify EP3 as a new therapeutic target for β-cell dysfunction in T2D. PMID:23349487

  17. Cytochrome P450 1A-like proteins expressed in the islets of Langerhans and altered pancreatic β-cell secretory responsiveness

    PubMed Central

    Clarke, Jacqueline; Flatt, Peter R; Barnett, Christopher R

    1997-01-01

    The cytochrome P450 (CYP) mixed-function oxidase system is widely distributed in body tissues and plays a key role in the metabolism of endogenous and exogenous compounds. Little attention has been paid to the expression of the system in the islets of Langerhans. The current study has examined the expression and potential role of the CYP1A family within the islets of Langerhans of control and 3-methylcholanthrene (3-MC)-induced Wistar rats. CYP1A expression within pancreatic slices and islets from 3-MC-induced and control rats demonstrated that CYP1A-like protein levels were induced by 3-MC pretreatment (25 mg kg−1 day−1; i.p. for 3 days). Effects of 3-MC-induction on β-cell secretory responsiveness were investigated by use of rat collagenase-isolated islets. Insulin release from control islets incubated with 3 mM glucose (basal) was 1.4±0.2 ng/islet h−1 (mean±s.e.mean, n=7). Incubation with 16.7 mM glucose, 25 mM KCl, 100 μM arachidonic acid, or 100 μM carbachol caused a 4.4, 7.0, 4.0 and 4.2 fold, respectively, increase in insulin release (P<0.001). Forskolin (2 μM), or phorbol 12-myristic 13-acetate (10 nM) potentiated glucose-stimulated insulin release 1.2 and 1.6 fold (P<0.01) whereas adenalin (1 μM) caused a 76% inhibition (P<0.01). Islets from 3-MC pretreated animals displayed similar responsiveness to all agents tested except arachidonic acid, carbachol and forskolin. Insulin release in response to arachidonic acid and carbachol was enhanced 5.2 and 5.0 fold, respectively, by 3-MC pretreatment (P<0.001 compared to control islets incubated with 3 mM glucose); the effect of forskolin on insulin output was significantly decreased (20%; P<0.01) compared to control islets. 3-MC pretreatment did not cause any significant differences in food intake, plasma glucose or total islet insulin content. Incubation of islets with 3-MC in vitro (1 μM–10 mM) did not affect basal or glucose-stimulated insulin release. These data

  18. Hormonal Responses to Noncontact Aggression in Convict Cichlid Fish.

    PubMed

    Scarsella, Grace E; Duque, Kevin S; Wong, Stephanie C; Sivaraman, Boopathy; Earley, Ryan L

    2016-03-01

    This study explored whether convict cichlid fish mount a hormonal response to aggressive encounters where dominance status remains unresolved. Hormone samples were collected at two time points before an aggressive interaction to obtain confinement-induced and baseline measures, and at one time point following a contest across a clear partition (experimental) or exposure to an opaque partition with an opponent on the opposite side (control). There was no overall significant effect of treatment (control vs. experimental) on hormone release rates but there were trends for cortisol and testosterone (T). A priori linear contrasts showed that individuals that engaged in aggressive interactions had lower postfight cortisol and T release rates than controls, suggesting that aggression, in this context, might attenuate the synthesis of both hormones. Cortisol decreased significantly between initial confinement and baseline, indicating that individuals habituate to the water-borne hormone collection procedure. Contrary to expectation, individuals with higher baseline T and 11-ketotestosterone (KT) release rates took longer to initiate conflict. None of the other measures of behavior were predicted by baseline hormone release rates, and contest behavior did not predict postfight hormone release rates. There was a significant positive relationship between KT and T at all time points. As with studies that employ mirror image stimulation, we found no hormonal response to unresolved contests despite high levels of aggressive behavior. Our study is unique because we demonstrate that animals engaged in conflict with live opponents also do not mount a significant hormonal response when clear dominance relationships are not established. PMID:27076438

  19. Islet Xeno/transplantation and the risk of contagion: local responses from Canada and Australia to an emerging global technoscience.

    PubMed

    Cheng, Myra

    2015-01-01

    This paper situates the public debate over the use of living animal organs and tissue for human therapies within the history of experimental islet transplantation. Specifically, the paper compares and contrasts the Canadian and Australian responses on xenotransplantation to consider what lessons can be learnt about the regulation of a complex and controversial biotechnology. Sobbrio and Jorqui described public engagement on xenotransplantation in these countries as 'important forms of experimental democracy.' While Canada experimented with a novel nation-wide public consultation, Australia sought public input within the context of a national inquiry. In both instances, the outcome was a temporary moratorium on all forms of clinical xenotransplantation comparable to the policies adopted in some European countries. In addition, the Australian xenotransplantation ban coincided with a temporary global ban on experimental islet allotransplantation in 2007. Through historical and comparative research, this paper investigates how public controversies over organ and tissue transplantation can inform our understanding of the mediation of interspeciality and the regulation of a highly contested technoscience. It offers an alternative perspective on the xenotransplantation controversy by exploring the ways in which coinciding moratoriums on islet allograft and xenograft challenge, complicate and confound our assumptions regarding the relationships between human and animal, between routine surgery and clinical experimentation, between biomedical science and social science, and between disease risks and material contagion. PMID:26497322

  20. Metabolic and hormonal responses to exercise in partially hepatectomised rats.

    PubMed

    Lavoie, J M; Warren, C; Arcelin, K; Latour, M G; Désy, F; Shinoda, M; Ethier, C; Gascon-Barré, M

    1998-06-01

    To characterise how the liver affects metabolic and hormonal exercise responses, hepatectomised (70%; HX) rats were submitted to a 30- or 50-min treadmill exercise (26 m/min, 0% slope) 48 hr or 7 days after surgery (reduced or normal liver mass, respectively). To determine whether metabolic effects of liver mass reduction during exercise were caused by reduced capacity of the liver to produce glucose, metabolic and hormonal responses to the same exercise protocol were measured in 48-hr HX rats. Euglycemia, maintained by exogenous glucose infusion, produced attenuated lactate, insulin, and glucagon values in 48-hr HX rats but did not affect FFA, glycerol, and plasma catecholamine responses. Results indicate that metabolic and hormonal exercise responses are amplified in 48-hr HX rats. Maintaining euglycemia in 48-hr HX rats during exercise does not reduce all responses. Intrahepatic events, similar to those in a short-term (48-hr) HX liver, may influence metabolic and hormonal exercise responses. PMID:9615872

  1. A single-islet microplate assay to measure mouse and human islet insulin secretion.

    PubMed

    Truchan, Nathan A; Brar, Harpreet K; Gallagher, Shannon J; Neuman, Joshua C; Kimple, Michelle E

    2015-01-01

    One complication to comparing β-cell function among islet preparations, whether from genetically identical or diverse animals or human organ donors, is the number of islets required per assay. Islet numbers can be limiting, meaning that fewer conditions can be tested; other islet measurements must be excluded; or islets must be pooled from multiple animals/donors for each experiment. Furthermore, pooling islets negates the possibility of performing single-islet comparisons. Our aim was to validate a 96-well plate-based single islet insulin secretion assay that would be as robust as previously published methods to quantify glucose-stimulated insulin secretion from mouse and human islets. First, we tested our new assay using mouse islets, showing robust stimulation of insulin secretion 24 or 48 h after islet isolation. Next, we utilized the assay to quantify mouse islet function on an individual islet basis, measurements that would not be possible with the standard pooled islet assay methods. Next, we validated our new assay using human islets obtained from the Integrated Islet Distribution Program (IIDP). Human islets are known to have widely varying insulin secretion capacity, and using our new assay we reveal biologically relevant factors that are significantly correlated with human islet function, whether displayed as maximal insulin secretion response or fold-stimulation of insulin secretion. Overall, our results suggest this new microplate assay will be a useful tool for many laboratories, expert or not in islet techniques, to be able to precisely quantify islet insulin secretion from their models of interest. PMID:26452321

  2. Distinct differences in the responses of the human pancreatic β-cell line EndoC-βH1 and human islets to proinflammatory cytokines.

    PubMed

    Oleson, Bryndon J; McGraw, Jennifer A; Broniowska, Katarzyna A; Annamalai, Mani; Chen, Jing; Bushkofsky, Justin R; Davis, Dawn B; Corbett, John A; Mathews, Clayton E

    2015-09-01

    While insulinoma cells have been developed and proven to be extremely useful in studies focused on mechanisms controlling β-cell function and viability, translating findings to human β-cells has proven difficult because of the limited access to human islets and the absence of suitable insulinoma cell lines of human origin. Recently, a human β-cell line, EndoC-βH1, has been derived from human fetal pancreatic buds. The purpose of this study was to determine whether human EndoC-βH1 cells respond to cytokines in a fashion comparable to human islets. Unlike most rodent-derived insulinoma cell lines that respond to cytokines in a manner consistent with rodent islets, EndoC-βH1 cells fail to respond to a combination of cytokines (IL-1, IFN-γ, and TNF) in a manner consistent with human islets. Nitric oxide, produced following inducible nitric oxide synthase (iNOS) expression, is a major mediator of cytokine-induced human islet cell damage. We show that EndoC-βH1 cells fail to express iNOS or produce nitric oxide in response to this combination of cytokines. Inhibitors of iNOS prevent cytokine-induced loss of human islet cell viability; however, they do not prevent cytokine-induced EndoC-βH1 cell death. Stressed human islets or human islets expressing heat shock protein 70 (HSP70) are resistant to cytokines, and, much like stressed human islets, EndoC-βH1 cells express HSP70 under basal conditions. Elevated basal expression of HSP70 in EndoC-βH1 cells is consistent with the lack of iNOS expression in response to cytokine treatment. While expressing HSP70, EndoC-βH1 cells fail to respond to endoplasmic reticulum stress activators, such as thapsigargin. These findings indicate that EndoC-βH1 cells do not faithfully recapitulate the response of human islets to cytokines. Therefore, caution should be exercised when making conclusions regarding the actions of cytokines on human islets when using this human-derived insulinoma cell line. PMID:26084699

  3. Young capillary vessels rejuvenate aged pancreatic islets

    PubMed Central

    Almaça, Joana; Molina, Judith; Arrojo e Drigo, Rafael; Abdulreda, Midhat H.; Jeon, Won Bae; Berggren, Per-Olof; Caicedo, Alejandro; Nam, Hong Gil

    2014-01-01

    Pancreatic islets secrete hormones that play a key role in regulating blood glucose levels (glycemia). Age-dependent impairment of islet function and concomitant dysregulation of glycemia are major health threats in aged populations. However, the major causes of the age-dependent decline of islet function are still disputed. Here we demonstrate that aging of pancreatic islets in mice and humans is notably associated with inflammation and fibrosis of islet blood vessels but does not affect glucose sensing and the insulin secretory capacity of islet beta cells. Accordingly, when transplanted into the anterior chamber of the eye of young mice with diabetes, islets from old mice are revascularized with healthy blood vessels, show strong islet cell proliferation, and fully restore control of glycemia. Our results indicate that beta cell function does not decline with age and suggest that islet function is threatened by an age-dependent impairment of islet vascular function. Strategies to mitigate age-dependent dysregulation in glycemia should therefore target systemic and/or local inflammation and fibrosis of the aged islet vasculature. PMID:25404292

  4. Islet amyloid polypeptide and high hydrostatic pressure: towards an understanding of the fibrillization process

    NASA Astrophysics Data System (ADS)

    Lopes, D. H. J.; Smirnovas, V.; Winter, R.

    2008-07-01

    Type II Diabetes Mellitus is a disease which is characterized by peripheral insulin resistance coupled with a progressive loss of insulin secretion that is associated with a decrease in pancreatic islet β-cell mass and the deposition of amyloid in the extracellular matrix of β-cells, which lead to islet cell death. The principal component of the islet amyloid is a pancreatic hormone called islet amyloid polypeptide (IAPP). High-pressure coupled with FT-IR, CD, ThT fluorescence spectroscopic and AFM studies were carried out to reveal information on the aggregation pathway as well as the aggregate structure of IAPP. Our data indicate that IAPP pre-formed fibrils exhibit a strong polymorphism with heterogeneous structures very sensitive to high hydrostatic pressure, indicating a high percentage of ionic and hydrophobic interactions being responsible for the stability the IAPP fibrils.

  5. Metabolomics applied to the pancreatic islet

    PubMed Central

    Gooding, Jessica R.; Jensen, Mette V.; Newgard, Christopher B.

    2016-01-01

    Metabolomics, the characterization of the set of small molecules in a biological system, is advancing research in multiple areas of islet biology. Measuring a breadth of metabolites simultaneously provides a broad perspective on metabolic changes as the islets respond dynamically to metabolic fuels, hormones, or environmental stressors. As a result, metabolomics has the potential to provide new mechanistic insights into islet physiology and pathophysiology. Here we summarize advances in our understanding of islet physiology and the etiologies of type-1 and type-2 diabetes gained from metabolomics studies. PMID:26116790

  6. Metabolomics applied to the pancreatic islet.

    PubMed

    Gooding, Jessica R; Jensen, Mette V; Newgard, Christopher B

    2016-01-01

    Metabolomics, the characterization of the set of small molecules in a biological system, is advancing research in multiple areas of islet biology. Measuring a breadth of metabolites simultaneously provides a broad perspective on metabolic changes as the islets respond dynamically to metabolic fuels, hormones, or environmental stressors. As a result, metabolomics has the potential to provide new mechanistic insights into islet physiology and pathophysiology. Here we summarize advances in our understanding of islet physiology and the etiologies of type-1 and type-2 diabetes gained from metabolomics studies. PMID:26116790

  7. New insights into the role of connexins in pancreatic islet function and diabetes

    PubMed Central

    Farnsworth, Nikki L.; Benninger, Richard K.P.

    2014-01-01

    Multi-cellular systems require complex signaling mechanisms for proper tissue function, to mediate signaling between cells in close proximity and at distances. This holds true for the islets of Langerhans, which are multicellular micro-organs located in the pancreas responsible for glycemic control, through secretion of insulin and other hormones. Coupling of electrical and metabolic signaling between islet β-cells is required for proper insulin secretion and effective glycemic control. β-cell specific coupling is established through gap junctions composed of connexin36, which results in coordinated insulin release across the islet. Islet connexins have been implicated in both Type-1 and Type-2 diabetes; however a clear link remains to be determined. The goal of this review is to discuss recent discoveries regarding the role of connexins in regulating insulin secretion, the regulation of connexins within the islet, and recent studies which support a role for connexins in diabetes. Further studies which investigate the regulation of connexins in the islet and their role in diabetes may lead to novel diabetes therapies which regulate islet function and β-cell survival through modulation of gap junction coupling. PMID:24583073

  8. Islet inflammation and hyperplasia induced by the pancreatic islet-specific overexpression of interleukin-6 in transgenic mice.

    PubMed Central

    Campbell, I. L.; Hobbs, M. V.; Dockter, J.; Oldstone, M. B.; Allison, J.

    1994-01-01

    Interleukin-6 (IL-6) is thought to be involved in the pathogenesis of autoimmune insulin-dependent diabetes mellitus. To examine this possibility, we developed two lines of transgenic mice (termed RIP-IL6) which overexpressed IL-6 in the pancreatic islet beta cells. RIP-IL6 mice, while showing a modest reduction in body weight, remained normoglycemic throughout their lives. Furthermore, insulin gene expression and glucose tolerance were similar to non-transgenic littermates. Histopathological examination revealed significant changes in the pancreas but not other organs of RIP-IL6 animals, with marked alterations in the architecture of the islets, in the islet cells, and in surrounding tissues. In younger animals these changes included islet hyperplasia with increased mitotic figures, neo-ductular formation, fibrosis, and a scant mononuclear cell infiltration (insulitis). In addition, immunostaining for islet hormones revealed changes in both the topography and density of beta and alpha cells. In older RIP-IL6 mice, a more florid insulitis was observed which was composed predominantly of B220+ B lymphocytes and, to a lesser extent, Mac-1+ macrophages and CD4+ and CD8+ T lymphocytes. Immunostaining for mouse IgG revealed significant numbers of plasma cells in the peri-islet infiltrates, which suggested that IL-6 induced differentiation of the recruited B lymphocytes. Therefore, islet overexpression of IL-6 produces a complex, localized host response implicating this cytokine in not only inflammatory processes that occur in autoimmune diabetes but also cellular neogenesis, which may indicate a role in tissue repair. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:8030746

  9. Chronic glucolipotoxic conditions in pancreatic islets impair insulin secretion due to dysregulated calcium dynamics, glucose responsiveness and mitochondrial activity

    PubMed Central

    2013-01-01

    Background In the progression towards diabetes, glucolipotoxicity is one of the main causes of pancreatic beta cell pathology. The aim of this study was to examine the in vitro effects of chronic glucolipotoxic conditions on cellular responses in pancreatic islets, including glucose and fat metabolism, Calcium mobilization, insulin secretion and insulin content. Results Exposure of islets to chronic glucolipotoxic conditions decreased glucose stimulated insulin secretion in vitro. Reduced protein levels of Glut2/slc2a2, and decreased glucokinase and pyruvate carboxylase mRNA levels indicated a significant lowering in glucose sensing. Concomitantly, both fatty acid uptake and triglyceride accumulation increased significantly while fatty acid oxidation decreased. This general suppression in glucose metabolism correlated well with a decrease in mitochondrial number and activity, reduction in cellular ATP content and dampening of the TCA cycle. Further, we also observed a decrease in IP3 levels and lower Calcium mobilization in response to glucose. Importantly, chronic glucolipotoxic conditions in vitro decreased insulin gene expression, insulin content, insulin granule docking (to the plasma membrane) and insulin secretion. Conclusions Our results present an integrated view of the effects of chronic glucolipotoxic conditions on known and novel signaling events, in vitro, that results in reduced glucose responsiveness and insulin secretion. PMID:23815372

  10. Pancreatic Islet APJ Deletion Reduces Islet Density and Glucose Tolerance in Mice.

    PubMed

    Han, Song; Englander, Ella W; Gomez, Guillermo A; Rastellini, Cristiana; Quertermous, Thomas; Kundu, Ramendra K; Greeley, George H

    2015-07-01

    Protection and replenishment of a functional pancreatic β-cell mass (BCM) are key goals of all diabetes therapies. Apelin, a small regulatory peptide, is the endogenous ligand for the apelin receptor (APJ) receptor. The apelin-APJ signaling system is expressed in rodent and human islet cells. Apelin exposure has been shown to inhibit and to stimulate insulin secretion. Our aim was to assess the influence of a selective APJ deletion in pancreatic islet cells on islet homeostasis and glucose tolerance in mice. Cre-LoxP strategy was utilized to mediate islet APJ deletion. APJ deletion in islet cells (APJ(Δislet)) resulted in a significantly reduced islet size, density and BCM. An ip glucose tolerance test showed significantly impaired glucose clearance in APJ(Δislet) mice. APJ(Δislet) mice were not insulin resistant and in vivo glucose-stimulated insulin secretion was reduced modestly. In vitro glucose-stimulated insulin secretion showed a significantly reduced insulin secretion by islets from APJ(Δislet) mice. Glucose clearance in response to ip glucose tolerance test in obese APJ(Δislet) mice fed a chronic high-fat (HF) diet, but not pregnant APJ(Δislet) mice, was impaired significantly. In addition, the obesity-induced adaptive elevations in mean islet size and fractional islet area were reduced significantly in obese APJ(Δislet) mice when compared with wild-type mice. Together, these findings demonstrate a stimulatory role for the islet cell apelin-APJ signaling axis in regulation of pancreatic islet homeostasis and in metabolic induced β-cell hyperplasia. The results indicate the apelin-APJ system can be exploited for replenishment of BCM. PMID:25965959

  11. Hormone-controlled UV-B responses in plants.

    PubMed

    Vanhaelewyn, Lucas; Prinsen, Els; Van Der Straeten, Dominique; Vandenbussche, Filip

    2016-08-01

    Ultraviolet B (UV-B) light is a portion of solar radiation that has significant effects on the development and metabolism of plants. Effects of UV-B on plants can be classified into photomorphogenic effects and stress effects. These effects largely rely on the control of, and interactions with, hormonal pathways. The fairly recent discovery of the UV-B-specific photoreceptor UV RESISTANCE LOCUS 8 (UVR8) allowed evaluation of the role of downstream hormones, leading to the identification of connections with auxin and gibberellin. Moreover, a substantial overlap between UVR8 and phytochrome responses has been shown, suggesting that part of the responses caused by UVR8 are under PHYTOCHROME INTERACTING FACTOR control. UV-B effects can also be independent of UVR8, and affect different hormonal pathways. UV-B affects hormonal pathways in various ways: photochemically, affecting biosynthesis, transport, and/or signaling. This review concludes that the effects of UV-B on hormonal regulation can be roughly divided in two: inhibition of growth-promoting hormones; and the enhancement of environmental stress-induced defense hormones. PMID:27401912

  12. Chromosomal mapping of pancreatic islet morphological features and regulatory hormones in the spontaneously diabetic (Type 2) Goto-Kakizaki rat.

    PubMed

    Finlay, Clare; Argoud, Karène; Wilder, Steven P; Ouali, Fetta; Ktorza, Alain; Kaisaki, Pamela J; Gauguier, Dominique

    2010-10-01

    Insulin resistance and altered endocrine pancreas function are central pathophysiological features of type 2 diabetes mellitus (T2DM). The Goto-Kakizaki (GK) rat is a model of spontaneous T2DM characterised by reduced beta cell mass and genetically determined glucose intolerance and altered insulin secretion. To identify genetic determinants of endocrine pancreas histopathology, we carried out quantitative trait locus (QTL) mapping of histological phenotypes (beta cell mass -BCM and insulin-positive cell area -IPCA) and plasma concentration of hormones and growth factors in a F2 cohort derived from GK and normoglycemic Brown Norway rats. Although IPCA and BCM in the duodenal region of the pancreas were highly positively correlated (P < 10(-6)), and similarly in the splenic region, both measures were poorly correlated when comparing duodenal and splenic phenotypes. Strongest evidence of linkage to pancreas morphological traits was obtained between BCM and chromosome 10 (LOD 3.2). Evidence of significant linkage (LOD 4.2) to plasma corticosterone was detected in a region of chromosome 1 distal to other QTLs previously identified in the GK. Male-specific genetic effects were detected, including linkages (LOD > 4) to growth hormome (GH) on chromosome 6 and prolactin on chromosome 17. These data suggest independent genetic control of the structure and function of ontologically different regions of the endocrine pancreas. Novel QTLs for corticosterone, prolactin and GH may contribute to diabetes in the GK. The QTLs that we have identified in this, and previous genetic studies collectively underline the complex and multiple mechanisms involved in diabetes in the GK strain. PMID:20878524

  13. Early hormonal changes affect the catabolic response to trauma.

    PubMed Central

    Bessey, P Q; Lowe, K A

    1993-01-01

    OBJECTIVE: The authors sought to determine how temporary insulin suppression might alter the catabolic effects of cortisol, glucagon, and epinephrine. SUMMARY BACKGROUND DATA: The metabolic responses to injury include hypermetabolism, accelerated net skeletal muscle protein breakdown, glucose intolerance, and insulin resistance. These alterations are associated with increased stress hormone concentrations. Insulin elaboration is usually suppressed immediately after an injury but is abundant later during convalescence. An infusion of hydrocortisone, glucagon, and epinephrine increases both stress hormone concentrations and insulin levels. It induces many of the metabolic alterations seen in critically ill patients, but it does not affect net muscle breakdown. METHODS: Seven healthy adults received a stress hormone infusion for 3 days in two separate studies. During one study they, also received an infusion of the somatostatin analogue, octreotide (0.005 micrograms/kg/min), to suppress insulin elaboration for the first 24 hours. During the other study (control), insulin was permitted to rise unchecked. RESULTS: Stress hormone concentrations, hypermetabolism (+/- 20% above basal), and leukocytosis were similar during both study periods. When insulin elaboration was temporarily suppressed, whole-body nitrogen loss was increased during the first 48 hours, and the efflux of amino acids from the forearm after 72 hours of infusion was 60% greater than the control level. CONCLUSIONS: Temporary insulin suppression during physiologic increases in stress hormone concentrations amplified whole-body nitrogen loss and led to the development of accelerated net skeletal muscle protein breakdown. Early hormonal changes after an injury may affect the development of later catabolic responses. PMID:8215639

  14. This paper is a winner in the Undergraduate category for the SFB awards: Evaluation of the tissue response to alginate encapsulated islets in an omentum pouch model.

    PubMed

    Ibarra, Veronica; Appel, Alyssa A; Anastasio, Mark A; Opara, Emmanuel C; Brey, Eric M

    2016-07-01

    Islet transplantation is currently in clinical use as a treatment for type I diabetes, but donor shortages and long-term immunosuppression limit broad application. Alginate microcapsules coated with poly-l-ornithine can be used to encapsulate islets in an environment that allows diffusion of glucose, insulin, nutrients, and waste products while inhibiting cells and antibodies. While clinical trials are ongoing using islets encapsulated in alginate microbeads, there are concerns in regards to long-term stability. Evaluation of the local tissue response following implantation provides insight into the underlying mechanisms contributing to biomaterial failure, which can be used to the design of new material strategies. Macrophages play an important role in driving the response. In this study, the stability of alginate microbeads coated with PLO containing islets transplanted in the omentum pouch model was investigated. Biomaterial structure and the inflammatory response were characterized by X-ray phase contrast (XPC) μCT imaging, histology, and immunostaining. XPC allowed evaluation of microbead 3D structure and identification of failed and stable microbeads. A robust inflammatory response characterized by high cell density and the presence of pro-inflammatory macrophages was found around the failed grafts. The results obtained provide insight into the local tissue response and possible failure mechanisms for alginate microbeads. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1581-1590, 2016. PMID:27144389

  15. Signal-Response Modeling of Partial Hormone Feedback Networks

    PubMed Central

    Johnson, Michael L.; Veldhuis, Paula P.; Evans, William S.

    2009-01-01

    Background Endocrine feedback control networks are typically complex and contain multiple hormones, pools, and compartments. The hormones themselves commonly interact via multiple pathways and targets within the networks, and a complete description of such relationships may involve hundreds of parameters. In addition, it is often difficult, if not impossible, to collect experimental data pertaining to every component within the network. Therefore, the complete simultaneous analysis of such networks is challenging. Nevertheless, an understanding of these networks is critical for furthering our knowledge of hormonal regulation in both physiologic and pathophysiologic conditions. Methods We propose a novel approach for the analysis of dose-response relationships of subsets of hormonal feedback networks. The algorithm and signal-response quantification (SRQuant) software is based on convolution integrals, and tests whether several discretely measured input signals can be individually delayed, spread in time, transformed, combined, and discretely convolved with an elimination function to predict the time course of the concentration of an output hormone. Signal-response quantification is applied to examples from the endocrine literature to demonstrate its applicability to the analysis of the different endocrine networks. Results In one example, SRQuant determines the dose-response relationship by which one hormone regulates another, highlighting its advantages over other traditional methods. In a second example, for the first time (to the best of our knowledge), we show that the secretion of glucagon may be jointly controlled by the β and the δ cells. Conclusion We have developed a novel convolution integral-based approach, algorithm, and software (SRQuant) for the analysis of dose-response relationships within subsets of complex endocrine feedback control networks. PMID:20046649

  16. Efficient, Glucose Responsive, and Islet-Specific Transgene Expression by a Modified Rat Insulin Promoter

    PubMed Central

    Chai, Renjie; Chen, Shuyuan; Ding, Jiahuan; Grayburn, Paul A

    2009-01-01

    This study was done to improve efficiency and islet specificity of the rat insulin promoter (RIP). Various rat insulin promoter lengths were prepared and tested in vitro to drive luciferase reporter gene expression in INS1-cells, alpha-cells, acinar cells, ductal cells, and fibroblasts. The CMV promoter was used as a positive control. In addition, the DsRed reporter gene was administered in vivo to rat pancreas by ultrasound-targeted microbubble destruction (UTMD). Confocal microscopy was used to detect the presence and distribution of DsRed within the pancreas after UTMD. A modified RIP3.1 promoter, which includes portions of the insulin gene after its transcription start site is 5-fold more active in INS-1 cells than the full length RIP promoter or the CMV promoter. RIP3.1 is regulated by glucose level and various islet transcription factors in vitro, and exhibits activity in alpha-cells, but not exocrine cells. In vivo delivery of RIP3.1-DsRed resulted in expression of DsRed protein in beta-cells, and to a lesser extent alpha cells under normal glucose conditions. No DsRed signal was present in exocrine pancreas under RIP3.1. A modified rat insulin promoter, RIP3.1, efficiently and specifically directs gene expression to endocrine pancreas. PMID:19727136

  17. Differentiation of chicken umbilical cord mesenchymal stem cells into beta-like pancreatic islet cells.

    PubMed

    Bai, Chunyu; Gao, Yuhua; Li, Qian; Feng, Yuan; Yu, Yanze; Meng, Gentong; Zhang, Minghai; Guan, Weijun

    2015-04-01

    In this study, we explored the possibility of using in vitro differentiation to create functional beta-like islet cells from chicken umbilical cord mesenchymal stem cells (UCMSCs). Passaged UCMSCs were induced to differentiate into pancreatic beta-like islet cells. Differentiated cells were observed through dithizone staining, and Pdx1 and insulin expressed in differentiated cells were detected with immunofluorescence. Insulin and C-peptide production from differentiated cells were analyzed using ELISA and western blotting. Differentiated cells were found to not only express Pdx1, insulin, and C-peptide, but also to display a glucose-responsive secretion of these hormones. PMID:24303870

  18. Predicting Response to Hormonal Therapy and Survival in Men with Hormone Sensitive Metastatic Prostate Cancer

    PubMed Central

    Grivas, Petros D.; Robins, Diane M.; Hussain, Maha

    2014-01-01

    Androgen deprivation is the cornerstone of the management of metastatic prostate cancer. Despite several decades of clinical experience with this therapy there are no standard predictive biomarkers for response. Although several candidate genetic, hormonal, inflammatory, biochemical, metabolic biomarkers have been suggested as potential predictors of response and outcome, none has been prospectively validated nor has proven clinical utility to date. There is significant heterogeneity in the depth and duration of hormonal response and in the natural history of advanced disease; therefore to better optimize/individualize therapy and for future development, identification of biomarkers is critical. This review summarizes the current data on the role of several candidate biomarkers that have been evaluated in the advanced/metastatic disease setting. PMID:22705096

  19. Improving function and survival of pancreatic islets by endogenous production of glucagon-like peptide 1 (GLP-1).

    PubMed

    Wideman, Rhonda D; Yu, Irene L Y; Webber, Travis D; Verchere, C Bruce; Johnson, James D; Cheung, Anthony T; Kieffer, Timothy J

    2006-09-01

    Glucagon-like peptide 1 (GLP-1) is a hormone that has received significant attention as a therapy for diabetes because of its ability to stimulate insulin biosynthesis and release and to promote growth and survival of insulin-producing beta cells. While GLP-1 is produced from the proglucagon precursor by means of prohormone convertase (PC) 1/3 activity in enteroendocrine L cells, the same precursor is differentially processed by PC2 in pancreatic islet alpha cells to release glucagon, leaving GLP-1 trapped within a larger fragment with no known function. We hypothesized that we could induce GLP-1 production directly within pancreatic islets by means of delivery of PC1/3 and, further, that this intervention would improve the viability and function of islets. Here, we show that adenovirus-mediated expression of PC1/3 in alpha cells increases islet GLP-1 secretion, resulting in improved glucose-stimulated insulin secretion and enhanced survival in response to cytokine treatment. PC1/3 expression in alpha cells also improved performance after islet transplantation in a mouse model of type 1 diabetes, possibly by enhancing nuclear Pdx1 and insulin content of islet beta cells. These results demonstrate a unique strategy for liberating GLP-1 from directly within the target organ and highlight the potential for up-regulating islet GLP-1 production as a means of treating diabetes. PMID:16938896

  20. Isolated human islets require hyperoxia to maintain islet mass, metabolism, and function.

    PubMed

    Komatsu, Hirotake; Kang, Dongyang; Medrano, Leonard; Barriga, Alyssa; Mendez, Daniel; Rawson, Jeffrey; Omori, Keiko; Ferreri, Kevin; Tai, Yu-Chong; Kandeel, Fouad; Mullen, Yoko

    2016-02-12

    Pancreatic islet transplantation has been recognized as an effective treatment for Type 1 diabetes; however, there is still plenty of room to improve transplantation efficiency. Because islets are metabolically active they require high oxygen to survive; thus hypoxia after transplant is one of the major causes of graft failure. Knowing the optimal oxygen tension for isolated islets would allow a transplant team to provide the best oxygen environment during pre- and post-transplant periods. To address this issue and begin to establish empirically determined guidelines for islet maintenance, we exposed in vitro cultured islets to different partial oxygen pressures (pO2) and assessed changes in islet volume, viability, metabolism, and function. Human islets were cultured for 7 days in different pO2 media corresponding to hypoxia (90 mmHg), normoxia (160 mmHg), and hyerpoxia (270 or 350 mmHg). Compared to normoxia and hypoxia, hyperoxia alleviated the loss of islet volume, maintaining higher islet viability and metabolism as measured by oxygen consumption and glucose-stimulated insulin secretion responses. We predict that maintaining pre- and post-transplanted islets in a hyperoxic environment will alleviate islet volume loss and maintain islet quality thereby improving transplant outcomes. PMID:26801563

  1. Pancreatic Islet Transplantation

    MedlinePlus

    ... of immunosuppressive medications?" [ Top ] Collaborative Islet Transplant Registry Data In its 2010 annual report, 1 the Collaborative Islet Transplant Registry presented data on 571 patients who received pancreatic islet allo- ...

  2. Enhanced insulin secretion responsiveness and islet adrenergic desensitization after chronic norepinephrine suppression is discontinued in fetal sheep.

    PubMed

    Chen, Xiaochuan; Green, Alice S; Macko, Antoni R; Yates, Dustin T; Kelly, Amy C; Limesand, Sean W

    2014-01-01

    Intrauterine growth-restricted (IUGR) fetuses experience prolonged hypoxemia, hypoglycemia, and elevated norepinephrine (NE) concentrations, resulting in hypoinsulinemia and β-cell dysfunction. Previously, we showed that acute adrenergic blockade revealed enhanced insulin secretion responsiveness in the IUGR fetus. To determine whether chronic exposure to NE alone enhances β-cell responsiveness afterward, we continuously infused NE into fetal sheep for 7 days and, after terminating the infusion, evaluated glucose-stimulated insulin secretion (GSIS) and glucose-potentiated arginine-induced insulin secretion (GPAIS). During treatment, NE-infused fetuses had greater (P < 0.05) plasma NE concentrations and exhibited hyperglycemia (P < 0.01) and hypoinsulinemia (P < 0.01) compared with controls. GSIS during the NE infusion was also reduced (P < 0.05) compared with pretreatment values. GSIS and GPAIS were approximately fourfold greater (P < 0.01) in NE fetuses 3 h after the 7 days that NE infusion was discontinued compared with age-matched controls or pretreatment GSIS and GPAIS values of NE fetuses. In isolated pancreatic islets from NE fetuses, mRNA concentrations of adrenergic receptor isoforms (α1D, α2A, α2C, and β1), G protein subunit-αi-2, and uncoupling protein 2 were lower (P < 0.05) compared with controls, but β-cell regulatory genes were not different. Our findings indicate that chronic exposure to elevated NE persistently suppresses insulin secretion. After removal, NE fetuses demonstrated a compensatory enhancement in insulin secretion that was associated with adrenergic desensitization and greater stimulus-secretion coupling in pancreatic islets. PMID:24253046

  3. Hormones

    MedlinePlus

    Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work ... glands, which are special groups of cells, make hormones. The major endocrine glands are the pituitary, pineal, ...

  4. In Autoimmune Diabetes the Transition from Benign to Pernicious Insulitis Requires an Islet Cell Response to Tumor Necrosis Factor α

    PubMed Central

    Pakala, Syamasundar V.; Chivetta, Marylee; Kelly, Colleen B.; Katz, Jonathan D.

    1999-01-01

    The islet-infiltrating and disease-causing leukocytes that are a hallmark of insulin-dependent diabetes mellitus produce and respond to a set of cytokine molecules. Of these, interleukin 1β, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ are perhaps the most important. However, as pleiotropic molecules, they can impact the path leading to β cell apoptosis and diabetes at multiple points. To understand how these cytokines influence both the formative and effector phases of insulitis, it is critical to determine their effects on the assorted cell types comprising the lesion: the effector T cells, antigen-presenting cells, vascular endothelium, and target islet tissue. Here, we report using nonobese diabetic chimeric mice harboring islets deficient in specific cytokine receptors or cytokine-induced effector molecules to assess how these compartmentalized loss-of-function mutations alter the events leading to diabetes. We found that islets deficient in Fas, IFN-γ receptor, or inducible nitric oxide synthase had normal diabetes development; however, the specific lack of TNF- α receptor 1 (p55) afforded islets a profound protection from disease by altering the ability of islet-reactive, CD4+ T cells to establish insulitis and subsequently destroy islet β cells. These results argue that islet cells play a TNF-α–dependent role in their own demise. PMID:10190896

  5. Growth hormone responses to growth hormone-releasing hormone in Hand-Schüller-Christian Disease.

    PubMed

    Gelato, M C; Loriaux, D L; Merriam, G R

    1989-09-01

    Bolus doses of GH-releasing hormone (GHRH), 1 microgram/kg i.v., were given to two groups of adult patients with growth hormone deficiency (GHD): 9 with Hand-Schüller-Christian disease (HSCD, presumed hypothalamic GHD) and 9 with idiopathic GHD (IGHD, etiology unknown). Six patients in each group were then given further GHRH doses daily for 5 days, and the GH responses to GHRH were measured over 3 h on day 1 and day 5. Plasma levels of insulin-like growth factor-I (IGF-I) were measured twice daily on days 1 and 5 during GHRH treatment. All patients with HSCD had measurable GH responses to the first dose of GHRH, with a mean peak response of 6.4 +/- 2.1 ng/ml (mean +/- SE). Only 5 of 9 patients with IGHD had GH responses above the detection limits of the assay; their mean peak response, 1.3 +/- 0.2 ng/ml, was significantly lower than the GH responses of the HSCD patients (p less than 0.05). Responses in both groups of patients were lower than those previously observed in normal adult men (35 +/- 8 ng/ml; p less than 0.01). Five days of daily stimulation with GHRH significantly (p less than 0.01) increased the GH response in both groups of patients. The rise was greater in patients with HSCD than with IGHD (HSCD, 5.1 +/- 2.5 ng/ml on day 1, vs. 12.0 +/- 6.8 ng/ml on day 5; IGHD, 1.4 +/- 0.3 ng/ml vs. 2.9 +/- 0.6 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2507952

  6. Phase transitions in the multi-cellular regulatory behavior of pancreatic islet excitability.

    PubMed

    Hraha, Thomas H; Westacott, Matthew J; Pozzoli, Marina; Notary, Aleena M; McClatchey, P Mason; Benninger, Richard K P

    2014-09-01

    The pancreatic islets of Langerhans are multicellular micro-organs integral to maintaining glucose homeostasis through secretion of the hormone insulin. β-cells within the islet exist as a highly coupled electrical network which coordinates electrical activity and insulin release at high glucose, but leads to global suppression at basal glucose. Despite its importance, how network dynamics generate this emergent binary on/off behavior remains to be elucidated. Previous work has suggested that a small threshold of quiescent cells is able to suppress the entire network. By modeling the islet as a Boolean network, we predicted a phase-transition between globally active and inactive states would emerge near this threshold number of cells, indicative of critical behavior. This was tested using islets with an inducible-expression mutation which renders defined numbers of cells electrically inactive, together with pharmacological modulation of electrical activity. This was combined with real-time imaging of intracellular free-calcium activity [Ca2+]i and measurement of physiological parameters in mice. As the number of inexcitable cells was increased beyond ∼15%, a phase-transition in islet activity occurred, switching from globally active wild-type behavior to global quiescence. This phase-transition was also seen in insulin secretion and blood glucose, indicating physiological impact. This behavior was reproduced in a multicellular dynamical model suggesting critical behavior in the islet may obey general properties of coupled heterogeneous networks. This study represents the first detailed explanation for how the islet facilitates inhibitory activity in spite of a heterogeneous cell population, as well as the role this plays in diabetes and its reversal. We further explain how islets utilize this critical behavior to leverage cellular heterogeneity and coordinate a robust insulin response with high dynamic range. These findings also give new insight into emergent

  7. Quality of Air-Transported Human Islets for Single Islet Cell Preparations.

    PubMed

    Yamashita, Shingo; Ohashi, Kazuo; Utoh, Rie; Kin, Tatsuya; Shapiro, A M James; Yamamoto, Masakazu; Gotoh, Mitsukazu; Okano, Teruo

    2013-12-30

    In new generation medical therapies for type 1 diabetes mellitus (DM), cell-based approaches using pancreatic islets have attracted significant attention worldwide. In particular, dispersed islet cells obtained from isolated pancreatic islets have been a valuable source in the cell biology and tissue engineering fields. Our experimental approach to the development of new islet-based DM therapies consisted of creating a monolithic islet cell sheet format using dispersed islet cells. In this experiment, we explored the potential of internationally transporting human islets from Alberta, Canada to Tokyo, Japan and obtaining viable dispersed islet cells. A total of 34 batches of isolated and purified human islets were transported using a commercial air courier service. Prior to shipping, the human islets had been in culture for 0-108 h at the University of Alberta. The transportation period from Alberta to Tokyo was 2-5 days. The transported human islet cells were enzymatically dispersed as single cells in Tokyo. The number of single islet cells decreased as the number of transportation days increased. In contrast, cell viability was maintained regardless of the number of transportation days. The preshipment culture time had no effect on the number or viability of single cells dispersed in Tokyo. When dispersed single islet cells were plated on laminin-5-coated temperature-responsive polymer-grafted culture dishes, the cells showed favorable attachment followed by extension as a monolithic format. The present study demonstrated that long-distance transported human islets are a viable cell source for experiments utilizing dispersed human islet cells. PMID:26858878

  8. Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets

    PubMed Central

    Costes, Safia; Vandewalle, Brigitte; Tourrel-Cuzin, Cécile; Broca, Christophe; Linck, Nathalie; Bertrand, Gyslaine; Kerr-Conte, Julie; Portha, Bernard; Pattou, François; Bockaert, Joel; Dalle, Stéphane

    2009-01-01

    OBJECTIVE In type 2 diabetes, chronic hyperglycemia is detrimental to β-cells, causing apoptosis and impaired insulin secretion. The transcription factor cAMP-responsive element–binding protein (CREB) is crucial for β-cell survival and function. We investigated whether prolonged exposure of β-cells to high glucose affects the functional integrity of CREB. RESEARCH DESIGN AND METHODS INS-1E cells and rat and human islets were used. Gene expression was analyzed by RT-PCR and Western blotting. Apoptosis was detected by cleaved caspase-3 emergence, DNA fragmentation, and electron microscopy. RESULTS Chronic exposure of INS-1E cells and rat and human islets to high glucose resulted in decreased CREB protein expression, phosphorylation, and transcriptional activity associated with apoptosis and impaired β-cell function. High-glucose treatment increased CREB polyubiquitination, while treatment of INS-1E cells with the proteasome inhibitor MG-132 prevented the decrease in CREB content. The emergence of apoptosis in INS-1E cells with decreased CREB protein expression knocked down by small interfering RNA suggested that loss of CREB protein content induced by high glucose contributes to β-cell apoptosis. Loading INS-1E cells or human islets with a cell-permeable peptide mimicking the proteasomal targeting sequence of CREB blocked CREB degradation and protected INS-1E cells and human islets from apoptosis induced by high glucose. The insulin secretion in response to glucose and the insulin content were preserved in human islets exposed to high glucose and loaded with the peptide. CONCLUSIONS These studies demonstrate that the CREB degradation by the ubiquitin-proteasome pathway contributes to β-cell dysfunction and death upon glucotoxicity and provide new insight into the cellular mechanisms of glucotoxicity. PMID:19223597

  9. Noninvasive evaluation of the vascular response to transplantation of alginate encapsulated islets using the dorsal skin-fold model.

    PubMed

    Krishnan, Rahul; Arora, Rajan P; Alexander, Michael; White, Sean M; Lamb, Morgan W; Foster, Clarence E; Choi, Bernard; Lakey, Jonathan R T

    2014-01-01

    Alginate encapsulation reduces the risk of transplant rejection by evading immune-mediated cell injury and rejection; however, poor vascular perfusion results in graft failure. Since existing imaging models are incapable of quantifying the vascular response to biomaterial implants after transplantation, in this study, we demonstrate the use of in vivo laser speckle imaging (LSI) and wide-field functional imaging (WiFI) to monitor the microvascular environment surrounding biomaterial implants. The vascular response to two islet-containing biomaterial encapsulation devices, alginate microcapsules and a high-guluronate alginate sheet, was studied and compared after implantation into the mouse dorsal window chamber (N = 4 per implant group). Images obtained over a 14-day period using LSI and WiFI were analyzed using algorithms to quantify blood flow, hemoglobin oxygen saturation and vascular density. Using our method, we were able to monitor the changes in the peri-implant microvasculature noninvasively without the use of fluorescent dyes. Significant changes in blood flow, hemoglobin oxygen saturation and vascular density were noted as early as the first week post-transplant. The dorsal window chamber model enables comparison of host responses to transplanted biomaterials. Future experiments will study the effect of changes in alginate composition on the vascular and immune responses. PMID:24176195

  10. Noninvasive evaluation of the vascular response to transplantation of alginate encapsulated islets using the dorsal skin-fold model

    PubMed Central

    Krishnan, Rahul; Arora, Rajan P.; Alexander, Michael; White, Sean M.; Lamb, Morgan W.; Foster, Clarence E.; Choi, Bernard; Lakey, Jonathan R.T.

    2014-01-01

    Alginate encapsulation reduces the risk of transplant rejection by evading immune-mediated cell injury and rejection; however, poor vascular perfusion results in graft failure. Since existing imaging models are incapable of quantifying the vascular response to biomaterial implants after transplantation, in this study, we demonstrate the use of in vivo laser speckle imaging (LSI) and wide-field functional imaging (WiFI) to monitor the microvascular environment surrounding biomaterial implants. The vascular response to two islet-containing biomaterial encapsulation devices, alginate microcapsules and a high-guluronate alginate sheet, was studied and compared after implantation into the mouse dorsal window chamber (N = 4 per implant group). Images obtained over a 14-day period using LSI and WiFI were analyzed using algorithms to quantify blood flow, hemoglobin oxygen saturation and vascular density. Using our method, we were able to monitor the changes in the peri-implant microvasculature non-invasively without the use of fluorescent dyes. Significant changes in blood flow, hemoglobin oxygen saturation and vascular density were noted as early as the first week post-transplant. The dorsal window chamber model enables comparison of host responses to transplanted biomaterials. Future experiments will study the effect of changes in alginate composition on the vascular and immune responses. PMID:24176195

  11. Identification and characterization of a functional retinoic acid/thyroid hormone-response element upstream of the human insulin gene enhancer.

    PubMed Central

    Clark, A R; Wilson, M E; London, N J; James, R F; Docherty, K

    1995-01-01

    A deletion analysis of the human insulin gene extending to 2 kb upstream of the transcription start site provided evidence of regulatory sequences located upstream of the insulin-linked polymorphic region (ILPR). Within this ILPR-distal region is a sequence (Ink, for insulin kilobase upstream) which contains three potential nuclear hormone-receptor half-sites, closely matching the consensus sequence AGGTCA. These sequences are arranged as a palindromic element with zero spacing over-lapping a direct repeat with 2 bp spacing. The Ink sequence was used in electrophoretic mobility-shift assays within nuclear extracts from COS-7 cells overexpressing the vitamin D, thyroid hormone or retinoic acid receptors, or from an insulin-expressing hamster cell line, HIT-T15. These studies suggest that the insulin-expressing cell line contains thyroid hormone and retinoic acid receptors at least, and that these receptors are able to recognize the Ink sequence. Three copies of the Ink sequence were placed upstream of the thymidine kinase promoter and firefly luciferase reporter gene. In COS-7 cells expressing the appropriate nuclear hormone receptor, this construct was responsive to both thyroid hormone (18-fold) and all-trans-retinoic acid (31-fold). In HIT-T15 cells the same construct responded to all-trans-retinoic acid, but not to thyroid hormone. Within the context of a 2 kb insulin gene fragment, the Ink sequence was shown to be activated by retinoic acid and by the retinoic acid receptor, but acted as a negative element in the presence of both retinoic acid and the retinoic acid receptor. Mutagenesis studies demonstrated that the palindromic sequence was important for the retinoic acid response, and for binding of complexes containing retinoic acid receptor. In human islets of Langerhans, retinoic acid was shown to stimulate insulin mRNA levels. These results demonstrate that a functional nuclear hormone-receptor-response element is located upstream of the human ILPR. As

  12. Sex-Steroid Hormone Manipulation Reduces Brain Response to Reward.

    PubMed

    Macoveanu, Julian; Henningsson, Susanne; Pinborg, Anja; Jensen, Peter; Knudsen, Gitte M; Frokjaer, Vibe G; Siebner, Hartwig R

    2016-03-01

    Mood disorders are twice as frequent in women than in men. Risk mechanisms for major depression include adverse responses to acute changes in sex-steroid hormone levels, eg, postpartum in women. Such adverse responses may involve an altered processing of rewards. Here, we examine how women's vulnerability for mood disorders is linked to sex-steroid dynamics by investigating the effects of a pharmacologically induced fluctuation in ovarian sex steroids on the brain response to monetary rewards. In a double-blinded placebo controlled study, healthy women were randomized to receive either placebo or the gonadotropin-releasing hormone agonist (GnRHa) goserelin, which causes a net decrease in sex-steroid levels. Fifty-eight women performed a gambling task while undergoing functional MRI at baseline, during the mid-follicular phase, and again following the intervention. The gambling task enabled us to map regional brain activity related to the magnitude of risk during choice and to monetary reward. The GnRHa intervention caused a net reduction in ovarian sex steroids (estradiol and testosterone) and increased depression symptoms. Compared with placebo, GnRHa reduced amygdala's reactivity to high monetary rewards. There was a positive association between the individual changes in testosterone and changes in bilateral insula response to monetary rewards. Our data provide evidence for the involvement of sex-steroid hormones in reward processing. A blunted amygdala response to rewarding stimuli following a rapid decline in sex-steroid hormones may reflect a reduced engagement in positive experiences. Abnormal reward processing may constitute a neurobiological mechanism by which sex-steroid fluctuations provoke mood disorders in susceptible women. PMID:26245498

  13. Gastric Bypass Reduces Symptoms and Hormonal Responses in Hypoglycemia.

    PubMed

    Abrahamsson, Niclas; Börjesson, Joey Lau; Sundbom, Magnus; Wiklund, Urban; Karlsson, F Anders; Eriksson, Jan W

    2016-09-01

    Gastric bypass (GBP) surgery, one of the most common bariatric procedures, induces weight loss and metabolic effects. The mechanisms are not fully understood, but reduced food intake and effects on gastrointestinal hormones are thought to contribute. We recently observed that GBP patients have lowered glucose levels and frequent asymptomatic hypoglycemic episodes. Here, we subjected patients before and after undergoing GBP surgery to hypoglycemia and examined symptoms and hormonal and autonomic nerve responses. Twelve obese patients without diabetes (8 women, mean age 43.1 years [SD 10.8] and BMI 40.6 kg/m(2) [SD 3.1]) were examined before and 23 weeks (range 19-25) after GBP surgery with hyperinsulinemic-hypoglycemic clamp (stepwise to plasma glucose 2.7 mmol/L). The mean change in Edinburgh Hypoglycemia Score during clamp was attenuated from 10.7 (6.4) before surgery to 5.2 (4.9) after surgery. There were also marked postsurgery reductions in levels of glucagon, cortisol, and catecholamine and the sympathetic nerve responses to hypoglycemia. In addition, growth hormone displayed a delayed response but to a higher peak level. Levels of glucagon-like peptide 1 and gastric inhibitory polypeptide rose during hypoglycemia but rose less postsurgery compared with presurgery. Thus, GBP surgery causes a resetting of glucose homeostasis, which reduces symptoms and neurohormonal responses to hypoglycemia. Further studies should address the underlying mechanisms as well as their impact on the overall metabolic effects of GBP surgery. PMID:27313315

  14. Human islets and dendritic cells generate post-translationally modified islet autoantigens.

    PubMed

    McLaughlin, R J; de Haan, A; Zaldumbide, A; de Koning, E J; de Ru, A H; van Veelen, P A; van Lummel, M; Roep, B O

    2016-08-01

    The initiation of type 1 diabetes (T1D) requires a break in peripheral tolerance. New insights into neoepitope formation indicate that post-translational modification of islet autoantigens, for example via deamidation, may be an important component of disease initiation or exacerbation. Indeed, deamidation of islet autoantigens increases their binding affinity to the T1D highest-risk human leucocyte antigen (HLA) haplotypes HLA-DR3/DQ2 and -DR4/DQ8, increasing the chance that T cells reactive to deamidated autoantigens can be activated upon T cell receptor ligation. Here we investigated human pancreatic islets and inflammatory and tolerogenic human dendritic cells (DC and tolDC) as potential sources of deamidated islet autoantigens and examined whether deamidation is altered in an inflammatory environment. Islets, DC and tolDC contained tissue transglutaminase, the key enzyme responsible for peptide deamidation, and enzyme activity increased following an inflammatory insult. Islets treated with inflammatory cytokines were found to contain deamidated insulin C-peptide. DC, heterozygous for the T1D highest-risk DQ2/8, pulsed with native islet autoantigens could present naturally processed deamidated neoepitopes. HLA-DQ2 or -DQ8 homozygous DC did not present deamidated islet peptides. This study identifies both human islets and DC as sources of deamidated islet autoantigens and implicates inflammatory activation of tissue transglutaminase as a potential mechanism for islet and DC deamidation. PMID:26861694

  15. A Novel High-Throughput Assay for Islet Respiration Reveals Uncoupling of Rodent and Human Islets

    PubMed Central

    Wikstrom, Jakob D.; Sereda, Samuel B.; Stiles, Linsey; Elorza, Alvaro; Allister, Emma M.; Neilson, Andy; Ferrick, David A.; Wheeler, Michael B.; Shirihai, Orian S.

    2012-01-01

    Background The pancreatic beta cell is unique in its response to nutrient by increased fuel oxidation. Recent studies have demonstrated that oxygen consumption rate (OCR) may be a valuable predictor of islet quality and long term nutrient responsiveness. To date, high-throughput and user-friendly assays for islet respiration are lacking. The aim of this study was to develop such an assay and to examine bioenergetic efficiency of rodent and human islets. Methodology/Principal Findings The XF24 respirometer platform was adapted to islets by the development of a 24-well plate specifically designed to confine islets. The islet plate generated data with low inter-well variability and enabled stable measurement of oxygen consumption for hours. The F1F0 ATP synthase blocker oligomycin was used to assess uncoupling while rotenone together with myxothiazol/antimycin was used to measure the level of non-mitochondrial respiration. The use of oligomycin in islets was validated by reversing its effect in the presence of the uncoupler FCCP. Respiratory leak averaged to 59% and 49% of basal OCR in islets from C57Bl6/J and FVB/N mice, respectively. In comparison, respiratory leak of INS-1 cells and C2C12 myotubes was measured to 38% and 23% respectively. Islets from a cohort of human donors showed a respiratory leak of 38%, significantly lower than mouse islets. Conclusions/Significance The assay for islet respiration presented here provides a novel tool that can be used to study islet mitochondrial function in a relatively high-throughput manner. The data obtained in this study shows that rodent islets are less bioenergetically efficient than human islets as well as INS1 cells. PMID:22606219

  16. Review of vitreous islet cryopreservation

    PubMed Central

    Baicu, Simona

    2009-01-01

    Transplantation of pancreatic islets for the treatment of diabetes mellitus is widely anticipated to eventually provide a cure once a means for preventing rejection is found without reliance upon global immunosuppression. Long-term storage of islets is crucial for the organization of transplantation, islet banking, tissue matching, organ sharing, immuno-manipulation and multiple donor transplantation. Existing methods of cryopreservation involving freezing are known to be suboptimal providing only about 50% survival. The development of techniques for ice-free cryopreservation of mammalian tissues using both natural and synthetic ice blocking molecules, and the process of vitrification (formation of a glass as opposed to crystalline ice) has been a focus of research during recent years. These approaches have established in other tissues that vitrification can markedly improve survival by circumventing ice-induced injury. Here we review some of the underlying issues that impact the vitrification approach to islet cryopreservation and describe some initial studies to apply these new technologies to the long-term storage of pancreatic islets. These studies were designed to optimize both the pre-vitrification hypothermic exposure conditions using newly developed media and to compare new techniques for ice-free cryopreservation with conventional freezing protocols. Some practical constraints and feasible resolutions are discussed. Eventually the optimized techniques will be applied to clinical allografts and xenografts or genetically-modified islets designed to overcome immune responses in the diabetic host. PMID:20046679

  17. Hormonal Responses to Active and Passive Recovery After Load Carriage.

    PubMed

    Taipale, Ritva S; Heinaru, Siiri; Nindl, Bradley C; Vaara, Jani P; Santtila, Matti; Häkkinen, Keijo; Kyröläinen, Heikki

    2015-11-01

    Military operations often induce fatigue resulting from load carriage. Recovery promotes military readiness. This study investigated the acute effects of AR vs. PR after load carriage on maximal isometric leg extension force (MVC) and serum hormonal concentrations. Male reservists (27 ± 3 years, 180 ± 7 cm, 74 ± 11 kg, V[Combining Dot Above]O2max 64 ± 9 ml·kg⁻¹·min⁻¹) completed PR (n = 8) or AR (n = 8) after 50 minutes of loaded (16 kg) uphill (gradient 4.0%) treadmill marching at individual anaerobic threshold. No differences were observed between groups in relative changes in MVC during the marching loading, after AR or PR or the next morning. Significant differences in relative responses to AR and PR postmarching loading were observed in serum testosterone (T), cortisol, and sex-hormone binding globulin immediately post AR and PR; however the next morning, all serum hormone concentrations had returned to normal. This study did not reveal any significant differences between the effects of AR and PR after an hour-long marching protocol at approximately anaerobic threshold on MVC or serum hormones the morning after the experimental marching protocol. Thus, based on the variable measured in this study, marching performed by physically fit army reservists at an intensity at or below anaerobic threshold may not necessitate specialized recovery protocols. PMID:26506179

  18. Parathyroid hormone-related protein and its receptors: nuclear functions and roles in the renal and cardiovascular systems, the placental trophoblasts and the pancreatic islets

    PubMed Central

    Clemens, Thomas L; Cormier, Sarah; Eichinger, Anne; Endlich, Karlhans; Fiaschi-Taesch, Nathalie; Fischer, Evelyne; Friedman, Peter A; Karaplis, Andrew C; Massfelder, Thierry; Rossert, Jérôme; Schlüter, Klaus-Dieter; Silve, Caroline; Stewart, Andrew F; Takane, Karen; Helwig, Jean-Jacques

    2001-01-01

    The cloning of the so-called ‘parathyroid hormone-related protein' (PTHrP) in 1987 was the result of a long quest for the factor which, by mimicking the actions of PTH in bone and kidney, is responsible for the hypercalcemic paraneoplastic syndrome, humoral calcemia of malignancy. PTHrP is distinct from PTH in a number of ways. First, PTHrP is the product of a separate gene. Second, with the exception of a short N-terminal region, the structure of PTHrP is not closely related to that of PTH. Third, in contrast to PTH, PTHrP is a paracrine factor expressed throughout the body. Finally, most of the functions of PTHrP have nothing in common with those of PTH. PTHrP is a poly-hormone which comprises a family of distinct peptide hormones arising from post-translational endoproteolytic cleavage of the initial PTHrP translation products. Mature N-terminal, mid-region and C-terminal secretory forms of PTHrP are thus generated, each of them having their own physiologic functions and probably their own receptors. The type 1 PTHrP receptor, binding both PTH(1-34) and PTHrP(1-36), is the only cloned receptor so far. PTHrP is a PTH-like calciotropic hormone, a myorelaxant, a growth factor and a developmental regulatory molecule. The present review reports recent aspects of PTHrP pharmacology and physiology, including: (a) the identification of new peptides and receptors of the PTH/PTHrP system; (b) the recently discovered nuclear functions of PTHrP and the role of PTHrP as an intracrine regulator of cell growth and cell death; (c) the physiological and developmental actions of PTHrP in the cardiovascular and the renal glomerulo-vascular systems; (d) the role of PTHrP as a regulator of pancreatic beta cell growth and functions, and, (e) the interactions of PTHrP and calcium-sensing receptors for the control of the growth of placental trophoblasts. These new advances have contributed to a better understanding of the pathophysiological role of PTHrP, and will help to identify

  19. A transcriptional reference map of defence hormone responses in potato.

    PubMed

    Wiesel, Lea; Davis, Jayne L; Milne, Linda; Redondo Fernandez, Vanesa; Herold, Miriam B; Middlefell Williams, Jill; Morris, Jenny; Hedley, Pete E; Harrower, Brian; Newton, Adrian C; Birch, Paul R J; Gilroy, Eleanor M; Hein, Ingo

    2015-01-01

    Phytohormones are involved in diverse aspects of plant life including the regulation of plant growth, development and reproduction, as well as governing biotic and abiotic stress responses. We have generated a comprehensive transcriptional reference map of the early potato responses to exogenous application of the defence hormones abscisic acid, brassinolides (applied as epibrassinolide), ethylene (applied as the ethylene precursor aminocyclopropanecarboxylic acid), salicylic acid and jasmonic acid (applied as methyl jasmonate). Of the 39000 predicted genes on the microarray, a total of 2677 and 2473 genes were significantly differentially expressed at 1 h and 6 h after hormone treatment, respectively. Specific marker genes newly identified for the early hormone responses in potato include: a homeodomain 20 transcription factor (DMG400000248) for abscisic acid; a SAUR gene (DMG400016561) induced in epibrassinolide treated plants; an osmotin gene (DMG400003057) specifically enhanced by aminocyclopropanecarboxylic acid; a gene weakly similar to AtWRKY40 (DMG402007388) that was induced by salicylic acid; and a jasmonate ZIM-domain protein 1 (DMG400002930) which was specifically activated by methyl jasmonate. An online database has been set up to query the expression patterns of potato genes represented on the microarray that can also incorporate future microarray or RNAseq-based expression studies. PMID:26477733

  20. A transcriptional reference map of defence hormone responses in potato

    PubMed Central

    Wiesel, Lea; Davis, Jayne L.; Milne, Linda; Redondo Fernandez, Vanesa; Herold, Miriam B.; Middlefell Williams, Jill; Morris, Jenny; Hedley, Pete E.; Harrower, Brian; Newton, Adrian C.; Birch, Paul R. J.; Gilroy, Eleanor M.; Hein, Ingo

    2015-01-01

    Phytohormones are involved in diverse aspects of plant life including the regulation of plant growth, development and reproduction, as well as governing biotic and abiotic stress responses. We have generated a comprehensive transcriptional reference map of the early potato responses to exogenous application of the defence hormones abscisic acid, brassinolides (applied as epibrassinolide), ethylene (applied as the ethylene precursor aminocyclopropanecarboxylic acid), salicylic acid and jasmonic acid (applied as methyl jasmonate). Of the 39000 predicted genes on the microarray, a total of 2677 and 2473 genes were significantly differentially expressed at 1 h and 6 h after hormone treatment, respectively. Specific marker genes newly identified for the early hormone responses in potato include: a homeodomain 20 transcription factor (DMG400000248) for abscisic acid; a SAUR gene (DMG400016561) induced in epibrassinolide treated plants; an osmotin gene (DMG400003057) specifically enhanced by aminocyclopropanecarboxylic acid; a gene weakly similar to AtWRKY40 (DMG402007388) that was induced by salicylic acid; and a jasmonate ZIM-domain protein 1 (DMG400002930) which was specifically activated by methyl jasmonate. An online database has been set up to query the expression patterns of potato genes represented on the microarray that can also incorporate future microarray or RNAseq-based expression studies. PMID:26477733

  1. Islet Culture/Preservation Before Islet Transplantation.

    PubMed

    Noguchi, Hirofumi; Miyagi-Shiohira, Chika; Kurima, Kiyoto; Kobayashi, Naoya; Saitoh, Issei; Watanabe, Masami; Noguchi, Yasufumi; Matsushita, Masayuki

    2015-12-17

    Although islet culture prior to transplantation provides flexibility for the evaluation of isolated islets and the pretreatment of patients, it is well known that isolated islets deteriorate rapidly in culture. Human serum albumin (HSA) is used for medium supplementation instead of fetal bovine serum (FBS), which is typically used for islet culture research, to avoid the introduction of xenogeneic materials. However, FBS contains several factors that are beneficial to islet viability and which also neutralize the endogenous pancreatic enzymes or exogenous enzymes left over from the isolation process. Several groups have reported the comparison of cultures at 22°C and 37°C. Recent studies have demonstrated the superiority of 4°C preservation to 22°C and 37°C cultures. We herein review the current research on islet culture/preservation for clinical islet transplantation. PMID:26858905

  2. Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.

    PubMed Central

    Katakami, H; Downs, T R; Frohman, L A

    1986-01-01

    The effects of thyroidectomy (Tx) and thyroxine replacement (T4Rx) on pituitary growth hormone (GH) secretion and hypothalamic GH-releasing hormone (GRH) concentration were compared to define the mechanism of hypothyroid-associated GH deficiency. Thyroidectomized rats exhibited a complete loss of pulsatile GH secretion with extensive reduction in GRH responsiveness and pituitary GH content. Cultured pituitary cells from Tx rats exhibited reduced GRH sensitivity, maximal GH responsiveness, and intracellular cyclic AMP accumulation to GRH, while somatostatin (SRIF) suppressive effects on GH secretion were increased. Hypothalamic GRH content was also markedly reduced. T4Rx completely restored hypothalamic GRH content and spontaneous GH secretion despite only partial recovery of pituitary GH content, GRH and SRIF sensitivity, and intracellular cyclic AMP response to GRH. The results indicate multiple effects of hypothyroidism on GH secretion and suggest that a critical role of T4 in maintaining normal GH secretion, in addition to restoring GH synthesis, is related to its effect on hypothalamic GRH. Images PMID:2871046

  3. Hormonal, cardiovascular, and subjective responses to acute stress in smokers

    PubMed Central

    de Wit, Harriet

    2009-01-01

    Rationale There are complex relationships between stress and smoking; smoking may reduce the emotional discomfort of stress, yet nicotine activates stress systems and may alter responses to acute stress. It is important to understand how smoking affects physiological and psychological outcomes after stress and how these may interact to motivate smoking. Objectives This study aimed to examine the magnitude and time course of hormonal, cardiovascular, and psychological responses to acute psychosocial stress in smokers and non-smokers to investigate whether responses to acute stress are altered in smokers. Materials and methods Healthy male non-smokers (n=20) and smokers (n=15) participated in two experimental sessions involving a standardized public speaking stress procedure and a control non-stressful task. The outcome measures included self-reported mood, cardiovascular measures (heart rate and blood pressure), and plasma hormone levels (noradrenaline, cortisol, progesterone, and allopregnanolone). Results Smokers exhibited blunted increases in cortisol after the Trier Social Stress Test, and they reported greater and more prolonged subjective agitation than non-smokers. Stress-induced changes in progesterone were similar between smokers and non-smokers, although responses overall were smaller among smokers. Stress did not significantly alter levels of allopregnanolone, but smokers exhibited lower plasma concentrations of this neurosteroid. Conclusions These findings suggest that smoking dampens hormonal responses to stress and prolongs subjective discomfort. Dysregulated stress responses may represent a breakdown in the body’s ability to cope efficiently and effectively with stress and may contribute to smokers’ susceptibility to acute stress, especially during abstinence. PMID:18936915

  4. Diverse Hormone Response Networks in 41 Independent Drosophila Cell Lines

    PubMed Central

    Stoiber, Marcus; Celniker, Susan; Cherbas, Lucy; Brown, Ben; Cherbas, Peter

    2016-01-01

    Steroid hormones induce cascades of gene activation and repression with transformative effects on cell fate . Steroid transduction plays a major role in the development and physiology of nearly all metazoan species, and in the progression of the most common forms of cancer. Despite the paramount importance of steroids in developmental and translational biology, a complete map of transcriptional response has not been developed for any hormone . In the case of 20-hydroxyecdysone (ecdysone) in Drosophila melanogaster, these trajectories range from apoptosis to immortalization. We mapped the ecdysone transduction network in a cohort of 41 cell lines, the largest such atlas yet assembled. We found that the early transcriptional response mirrors the distinctiveness of physiological origins: genes respond in restricted patterns, conditional on the expression levels of dozens of transcription factors. Only a small cohort of genes is constitutively modulated independent of initial cell state. Ecdysone-responsive genes tend to organize into directional same-stranded units, with consecutive genes induced from the same strand. Here, we identify half of the ecdysone receptor heterodimer as the primary rate-limiting step in the response, and find that initial receptor isoform levels modulate the activated cohort of target transcription factors. This atlas of steroid response reveals organizing principles of gene regulation by a model type II nuclear receptor and lays the foundation for comprehensive and predictive understanding of the ecdysone transduction network in the fruit fly. PMID:26772746

  5. Diverse Hormone Response Networks in 41 Independent Drosophila Cell Lines

    DOE PAGESBeta

    Stoiber, Marcus; Celniker, Susan; Cherbas, Lucy; Brown, Ben; Cherbas, Peter

    2016-01-15

    Steroid hormones induce cascades of gene activation and repression with transformative effects on cell fate . Steroid transduction plays a major role in the development and physiology of nearly all metazoan species, and in the progression of the most common forms of cancer. Despite the paramount importance of steroids in developmental and translational biology, a complete map of transcriptional response has not been developed for any hormone . In the case of 20-hydroxyecdysone (ecdysone) in Drosophila melanogaster, these trajectories range from apoptosis to immortalization. We mapped the ecdysone transduction network in a cohort of 41 cell lines, the largest suchmore » atlas yet assembled. We found that the early transcriptional response mirrors the distinctiveness of physiological origins: genes respond in restricted patterns, conditional on the expression levels of dozens of transcription factors. Only a small cohort of genes is constitutively modulated independent of initial cell state. Ecdysone-responsive genes tend to organize into directional same-stranded units, with consecutive genes induced from the same strand. Here, we identify half of the ecdysone receptor heterodimer as the primary rate-limiting step in the response, and find that initial receptor isoform levels modulate the activated cohort of target transcription factors. In conclusion, this atlas of steroid response reveals organizing principles of gene regulation by a model type II nuclear receptor and lays the foundation for comprehensive and predictive understanding of the ecdysone transduction network in the fruit fly.« less

  6. Hormones

    MedlinePlus

    ... the foods you eat Sexual function Reproduction Mood Endocrine glands, which are special groups of cells, make hormones. The major endocrine glands are the pituitary, pineal, thymus, thyroid, adrenal ...

  7. Integrated perfusion and separation systems for entrainment of insulin secretion from islets of Langerhans.

    PubMed

    Yi, Lian; Wang, Xue; Dhumpa, Raghuram; Schrell, Adrian M; Mukhitov, Nikita; Roper, Michael G

    2015-02-01

    A microfluidic system was developed to investigate the entrainment of insulin secretion from islets of Langerhans to oscillatory glucose levels. A gravity-driven perfusion system was integrated with a microfluidic system to deliver sinusoidal glucose waveforms to the islet chamber. Automated manipulation of the height of the perfusion syringes allowed precise control of the ratio of two perfusion solutions into a chamber containing 1-10 islets. Insulin levels in the perfusate were measured using an online competitive electrophoretic immunoassay with a sampling period of 10 s. The insulin immunoassay had a detection limit of 3 nM with RSDs of calibration points ranging from 2-8%. At 11 mM glucose, insulin secretion from single islets was oscillatory with a period ranging from 3-6 min. Application of a small amplitude sinusoidal wave of glucose with a period of 5 or 10 min, shifted the period of the insulin oscillations to this forcing period. Exposing groups of 6-10 islets to a sinusoidal glucose wave synchronized their behavior, producing a coherent pulsatile insulin response from the population. These results demonstrate the feasibility of the developed system for the study of oscillatory insulin secretion and can be easily modified for investigating the dynamic nature of other hormones released from different cell types. PMID:25474044

  8. The acute hormonal response to the kettlebell swing exercise.

    PubMed

    Budnar, Ronald G; Duplanty, Anthony A; Hill, David W; McFarlin, Brian K; Vingren, Jakob L

    2014-10-01

    The purpose of this investigation was to examine the acute hormonal response to the kettlebell swing exercise. Ten recreationally resistance trained men (age, 24 ± 4 years; height, 175 ± 6 cm; body mass, 78.7 ± 9.9 kg) performed 12 rounds of 30 seconds of 16 kg kettlebell swings alternated with 30 seconds of rest. Blood samples were collected before (PRE), immediately after (IP), and 15 (P15) and 30 minutes after exercise (P30) and analyzed for testosterone (T), immunoreactive growth hormone, cortisol (C), and lactate concentrations. Heart rate and rating of perceived exertion were measured at the end of each round. Testosterone was significantly higher (p ≤ 0.05) at IP than at PRE, P15, or P30 (PRE: 28 ± 3; IP: 32 ± 4; P15: 29 ± 3; P30: 27 ± 3 nmol·L). Growth hormone was higher at IP, P15, and P30 than at PRE (PRE: 0.1 ± 0.1; IP: 1.8 ± 1.2; P15: 2.1 ± 1.1; P30: 1.6 ± 1.3 μg·L). Cortisol was higher at IP and P15 than at PRE and P30 (PRE: 617 ± 266; IP: 894 ± 354; P15: 875 ± 243; P30: 645 ± 285 nmol·L). Lactate was higher at IP, P15, and P30 than at PRE (PRE: 1.1 ± 0.5; IP: 7.0 ± 3.0; P15: 4.0 ± 2.7; P30: 2.5 ± 1.8 mmol·L). Heart rate increased progressively from 57 ± 12 at PRE to 170 ± 10 at IP. The exercise protocol produced an acute increase in hormones involved in muscle adaptations. Thus, the kettlebell swing exercise might provide a good supplement to resistance training programs. PMID:24714543

  9. Thyroid Hormone Promotes Postnatal Rat Pancreatic β-Cell Development and Glucose-Responsive Insulin Secretion Through MAFA

    PubMed Central

    Aguayo-Mazzucato, Cristina; Zavacki, Ann Marie; Marinelarena, Alejandra; Hollister-Lock, Jennifer; El Khattabi, Ilham; Marsili, Alessandro; Weir, Gordon C.; Sharma, Arun; Larsen, P. Reed; Bonner-Weir, Susan

    2013-01-01

    Neonatal β cells do not secrete glucose-responsive insulin and are considered immature. We previously showed the transcription factor MAFA is key for the functional maturation of β cells, but the physiological regulators of this process are unknown. Here we show that postnatal rat β cells express thyroid hormone (TH) receptor isoforms and deiodinases in an age-dependent pattern as glucose responsiveness develops. In vivo neonatal triiodothyronine supplementation and TH inhibition, respectively, accelerated and delayed metabolic development. In vitro exposure of immature islets to triiodothyronine enhanced the expression of Mafa, the secretion of glucose-responsive insulin, and the proportion of responsive cells, all of which are effects that were abolished in the presence of dominant-negative Mafa. Using chromatin immunoprecipitation and electrophoretic mobility shift assay, we show that TH has a direct receptor-ligand interaction with the Mafa promoter and, using a luciferase reporter, that this interaction was functional. Thus, TH can be considered a physiological regulator of functional maturation of β cells via its induction of Mafa. PMID:23305647

  10. Thyroid hormone promotes postnatal rat pancreatic β-cell development and glucose-responsive insulin secretion through MAFA.

    PubMed

    Aguayo-Mazzucato, Cristina; Zavacki, Ann Marie; Marinelarena, Alejandra; Hollister-Lock, Jennifer; El Khattabi, Ilham; Marsili, Alessandro; Weir, Gordon C; Sharma, Arun; Larsen, P Reed; Bonner-Weir, Susan

    2013-05-01

    Neonatal β cells do not secrete glucose-responsive insulin and are considered immature. We previously showed the transcription factor MAFA is key for the functional maturation of β cells, but the physiological regulators of this process are unknown. Here we show that postnatal rat β cells express thyroid hormone (TH) receptor isoforms and deiodinases in an age-dependent pattern as glucose responsiveness develops. In vivo neonatal triiodothyronine supplementation and TH inhibition, respectively, accelerated and delayed metabolic development. In vitro exposure of immature islets to triiodothyronine enhanced the expression of Mafa, the secretion of glucose-responsive insulin, and the proportion of responsive cells, all of which are effects that were abolished in the presence of dominant-negative Mafa. Using chromatin immunoprecipitation and electrophoretic mobility shift assay, we show that TH has a direct receptor-ligand interaction with the Mafa promoter and, using a luciferase reporter, that this interaction was functional. Thus, TH can be considered a physiological regulator of functional maturation of β cells via its induction of Mafa. PMID:23305647

  11. Acute salivary hormone responses to complex exercise bouts.

    PubMed

    Beaven, C Martyn; Gill, Nicholas D; Ingram, John R; Hopkins, Will G

    2011-04-01

    The combination of resistance and plyometric training, or complex training, may yield greater functional gains than either method alone. As steroid hormones respond to exercise stimuli and modulate the functional outcomes, it is possible that complex training creates an enhanced anabolic physiological milieu for adaptation. We investigated acute responses of salivary testosterone and cortisol to complex exercise bouts. After a standardized warm-up, 16 semiprofessional rugby players performed 1 of 4 exercise bouts in a cross-over manner: power-power; power-strength; strength-power; or strength-strength. Each player completed each of the 4 bouts twice over a 4-week period in a balanced random order such that each player performed a total of 8 bouts. The power block consisted of 3 sets of 3 repetitions of jump squat exercise at 50% of 1-repetition maximum load. The strength block consisted of three sets of three repetitions of box squat exercise at a 3-repetition maximum load. There were 3-minute rest periods between sets and 4-minute rest periods between exercise blocks. Saliva was sampled before, during, and immediately after the exercise bout. The greatest overall hormonal responses were a small increase in testosterone (13%; 90% confidence limits ± 7%) and a trivial increase in cortisol (27%; ± 30%) after the strength-power bout. A clear difference was observed between the strength-power and the power-power bouts immediately after exercise for testosterone (10%; ± 8%) and cortisol (29%; ± 17%). The preceding exercise block had little effect on subsequent strength and power performance. The hormonal response after the strength-power bout suggests that this exercise sequence provides an enhanced anabolic milieu for adaptation. PMID:20703172

  12. Growth hormone receptor polymorphism and growth hormone therapy response in children: a Bayesian meta-analysis.

    PubMed

    Renehan, Andrew G; Solomon, Mattea; Zwahlen, Marcel; Morjaria, Reena; Whatmore, Andrew; Audí, Laura; Binder, Gerhard; Blum, Werner; Bougnères, Pierre; Santos, Christine Dos; Carrascosa, Antonio; Hokken-Koelega, Anita; Jorge, Alexander; Mullis, Primus E; Tauber, Maïthé; Patel, Leena; Clayton, Peter E

    2012-05-01

    Recombinant human growth hormone (rhGH) therapy is used in the long-term treatment of children with growth disorders, but there is considerable treatment response variability. The exon 3-deleted growth hormone receptor polymorphism (GHR(d3)) may account for some of this variability. The authors performed a systematic review (to April 2011), including investigator-only data, to quantify the effects of the GHR(fl-d3) and GHR(d3-d3) genotypes on rhGH therapy response and used a recently established Bayesian inheritance model-free approach to meta-analyze the data. The primary outcome was the 1-year change-in-height standard-deviation score for the 2 genotypes. Eighteen data sets from 12 studies (1,527 children) were included. After several prior assumptions were tested, the most appropriate inheritance model was codominant (posterior probability = 0.93). Compared with noncarriers, carriers had median differences in 1-year change-in-height standard-deviation score of 0.09 (95% credible interval (CrI): 0.01, 0.17) for GHR(fl-d3) and of 0.14 (95% CrI: 0.02, 0.26) for GHR(d3-d3). However, the between-study standard deviation of 0.18 (95% CrI: 0.10, 0.33) was considerable. The authors tested by meta-regression for potential modifiers and found no substantial influence. They conclude that 1) the GHR(d3) polymorphism inheritance is codominant, contrasting with previous reports; 2) GHR(d3) genotypes account for modest increases in rhGH effects in children; and 3) considerable unexplained variability in responsiveness remains. PMID:22494952

  13. Growth Hormone Response after Administration of L-dopa, Clonidine, and Growth Hormone Releasing Hormone in Children with Down Syndrome.

    ERIC Educational Resources Information Center

    Pueschel, Seigfried M.

    1993-01-01

    This study of eight growth-retarded children with Down's syndrome (aged 1 to 6.5 years) found that administration of growth hormone was more effective than either L-dopa or clonidine. Results suggest that children with Down's syndrome have both anatomical and biochemical hypothalamic derangements resulting in decreased growth hormone secretion and…

  14. Thyroid Hormone Response Element Half-Site Organization and Its Effect on Thyroid Hormone Mediated Transcription

    PubMed Central

    Paquette, Martin A.; Atlas, Ella; Wade, Mike G.; Yauk, Carole L.

    2014-01-01

    Thyroid hormone (TH) exerts its effects by binding to the thyroid hormone receptor (TR), which binds to TH response elements (TREs) to regulate target gene expression. We investigated the relative ability of liganded homodimers TR and retinoid X receptor (RXR), and the heterodimer TR/RXR, to regulate gene expression for the TRE half-site organizations: direct repeat 4 (DR4), inverted repeat 0 (IR0) and everted repeat 6 (ER6). Luciferase reporter assays using a DR4 TRE suggest that both the TR homodimer and TR/RXR heterodimer regulate luciferase expression in the presence of their respective ligands. However, in the presence of the IR0 TRE, transfection with TR/RXR and RXR alone increased luciferase activity and there was no effect of TR alone. The presence of 9-cis-retinoic acid was necessary for luciferase expression, whereas TH treatment alone was insufficient. For the ER6 TRE, transfection with TR/RXR, TR alone and RXR alone (in the presence of their respective ligands) all caused a significant increase in luciferase activity. When both ligands were present, transfection with both TR/RXR caused more activation. Finally, we investigated the efficacy of the TR-antagonist 1–850 in inhibiting transcription by TR or TR/RXR at DR4 and ER6 TREs. We found that 1–850 did not suppress luciferase activation in the presence of TR/RXR for the ER6 TRE, suggesting conformational changes of the ligand binding domain of the TR when bound to different TRE half-site organizations. Collectively, the findings indicate that there are fundamental differences between TRE configurations that affect nuclear receptor interactions with the response element and ability to bind ligands and antagonists. PMID:24971931

  15. Clinical Islet Isolation.

    PubMed

    Hawthorne, Wayne J; Williams, Lindy; Chew, Yi Vee

    2016-01-01

    The overarching success of islet transplantation relies on the success in the laboratory to isolate the islets. This chapter focuses on the processes of human islet cell isolation and the ways to optimally provide islet cells for transplantation. The major improvements in regards to the choice of enzyme type, way the digested pancreas tissue is handled to best separate islets from the acinar and surrounding tissues, the various methods of purification of the islets, their subsequent culture and quality assurance to improve outcomes to culminate in safe and effective islet transplantation will be discussed. After decades of improvements, islet cell isolation and transplantation now clearly offer a safe, effective and feasible therapeutic treatment option for an increasing number of patients suffering from type 1 diabetes specifically for those with severe hypoglycaemic unawareness. PMID:27586424

  16. Pancreatic Islet Transplantation

    MedlinePlus

    ... allo-transplantation?" For each pancreatic islet allo-transplant infusion, researchers use specialized enzymes to remove islets from ... in a lab. Transplant patients typically receive two infusions with an average of 400,000 to 500, ...

  17. Growth Hormone Response to L-Dopa and Clonidine in Autistic Children.

    ERIC Educational Resources Information Center

    Realmuto, George M.; And Others

    1990-01-01

    Seven medication-free autistic subjects (ages 6-19) were administered clonidine and L-Dopa to investigate neuroendocrine responses through changes in growth hormone levels. Findings showed that, compared to normal controls, the L-Dopa-stimulated growth hormone peak was delayed and the clonidine growth hormone peak was premature. (Author/JDD)

  18. Orexin-1 Receptor Co-Localizes with Pancreatic Hormones in Islet Cells and Modulates the Outcome of Streptozotocin-Induced Diabetes Mellitus

    PubMed Central

    Adeghate, Ernest; Fernandez-Cabezudo, Maria; Hameed, Rashed; El-Hasasna, Hussain; El Wasila, Mohamed; Abbas, Tariq; al-Ramadi, Basel

    2010-01-01

    Recent studies have shown that orexins play a critical role in the regulation of sleep/wake states, feeding behaviour, and reward processes. The exocrine and endocrine pancreas are involved in the regulation of food metabolism and energy balance. This function is deranged in diabetes mellitus. This study examined the pattern of distribution of orexin-1 receptor (OX1R) in the endocrine cells of the pancreas of normal and diabetic Wistar (a model of type 1 diabetes), Goto-Kakizaki (GK, a model of type 2 diabetes) rats and in orexin-deficient (OX−/−) and wild type mice. Diabetes mellitus (DM) was induced in Wistar rats and mice by streptozotocin (STZ). At different time points (12 h, 24 h, 4 weeks, 8 months and 15 months) after the induction of DM, pancreatic fragments of normal and diabetic rats were processed for immunohistochemistry and Western blotting. OX1R-immunoreactive nerves were observed in the pancreas of normal and diabetic Wistar rats. OX1R was also discernible in the pancreatic islets of normal and diabetic Wistar and GK rats, and wild type mice. OX1R co-localized with insulin (INS) and glucagon (GLU) in the pancreas of Wistar and GK rats. The number of OX1R-positive cells in the islets increased markedly (p<0.0001) after the onset of DM. The increase in the number of OX1R-positive cells is associated with a high degree of co-localization with GLU. The number of GLU- positive cells expressing OX1R was significantly (p<0.0001) higher after the onset of DM. The tissue level of OX1R protein increased with the duration of DM especially in type 1 diabetes where it co-localized with cleaved caspase 3 in islet cells. In comparison to STZ-treated wild type mice, STZ-treated OX−/− animals exhibited reduced hyperglycemia and handled glucose more efficiently in glucose tolerance test. The findings suggest an important role for the OX-OX1R pathway in STZ-induced experimental diabetes. PMID:20062799

  19. Restoration of Glucose Counterregulation by Islet Transplantation in Long-standing Type 1 Diabetes.

    PubMed

    Rickels, Michael R; Fuller, Carissa; Dalton-Bakes, Cornelia; Markmann, Eileen; Palanjian, Maral; Cullison, Kevin; Tiao, Janice; Kapoor, Shiv; Liu, Chengyang; Naji, Ali; Teff, Karen L

    2015-05-01

    Patients with long-standing type 1 diabetes (T1D) may exhibit defective glucose counterregulation and impaired hypoglycemia symptom recognition that substantially increase their risk for experiencing severe hypoglycemia. The purpose of this study was to determine whether intrahepatic islet transplantation improves endogenous glucose production (EGP) in response to hypoglycemia in T1D patients experiencing severe hypoglycemia. We studied longitudinally subjects (n = 12) with ∼30 years, disease duration before and 6 months after intrahepatic islet transplantation using stepped hyperinsulinemic-hypoglycemic and paired hyperinsulinemic-euglycemic clamps with infusion of 6,6-(2)H2-glucose and compared the results with those from a nondiabetic control group (n = 8). After islet transplantation, HbA1c was normalized, and time spent while hypoglycemic (<70 mg/dL) was nearly abolished as indicated by continuous glucose monitoring. In response to insulin-induced hypoglycemia, C-peptide (absent before transplant) was appropriately suppressed, glucagon secretion was recovered, and epinephrine secretion was improved after transplantation. Corresponding to these hormonal changes, the EGP response to insulin-induced hypoglycemia, which was previously absent, was normalized after transplantation, with a similar effect seen for autonomic symptoms. Because the ability to increase EGP is ultimately required to circumvent the development of hypoglycemia, these results provide evidence that intrahepatic islet transplantation can restore glucose counterregulation in long-standing T1D and support its consideration as treatment for patients with hypoglycemia unawareness experiencing severe hypoglycemia. PMID:25524910

  20. The use of continuous density gradients for the assessment of islet and exocrine tissue densities and islet purification.

    PubMed

    Robertson, G S; Chadwick, D R; Contractor, H; James, R F; Bell, P R; London, N J

    1993-01-01

    The purification of large numbers of human pancreatic islets remains one of the limiting factors in islet transplantation. This paper describes and validates a method for accurately and reproducibly determining the density of islets and exocrine tissue in pancreatic digest on the basis of their isopycnic distribution on linear continuous density gradients. The use of this data to analyse and compare the purity of a standard 60% islet yield is described. The results obtained using such gradients will enable factors responsible for the variation in yield between pancreases to be determined and optimized, improving the results and reliability of islet purification. PMID:8111080

  1. Activation of intraislet lymphoid cells causes destruction of islet cells.

    PubMed Central

    Lacy, P. E.; Finke, E. H.

    1991-01-01

    In vitro culture of rat islets at 24 degrees C for 7 days in tissue culture medium CMRL 1066 almost completely eliminated lymphoid cells from the islets. Immunostaining of the islets with monoclonal antibody OX4 for demonstration of class II major histocompatibility complex (MHC)-expressing cells revealed a decrease from 13.1 +/- 0.6 positive cells per islet on day 0 to 0.7 +/- 0.1 cells per islet on day 7. A comparable decrease was found using OX1 for demonstration of all leukocytes. In contrast, culture of rat islets at 24 degrees C for 7 days with tissue culture Roswell Park Memorial Institute (RPMI) 1640 medium was not as effective in eliminating lymphoid cells as in medium CMRL 1066 (3.0 +/- 0.2 class II MHC positive cells per islet at 7 days). Effective elimination of intraislet lymphoid cells apparently is due to the combined effect of low temperature culture and the tissue culture medium CMRL-1066. The second goal of the study was to determine whether the destructive effect of interferon gamma (IFN-gamma) on rat islets in culture was due to intraislet lymphoid cells. In vitro culture of rat islets with IFN-gamma (1000 units/ml) at 37 degrees C caused almost complete destruction of the islets at 7 days. If intraislet lymphoid cells were eliminated from the islets by in vitro culture at 24 degrees C followed by exposure to IFN-gamma (1000 units/ml) for 7 days at 37 degrees C, then IFN-gamma did not cause destruction of the islets and transplants of the treated islets produced normoglycemia in diabetic recipient mice. These findings indicate that intraislet lymphoid cells are responsible for destruction of islet cells when these cells (presumably macrophages) are activated by IFN-gamma. Intraislet lymphoid cells may play a significant role in destroying islet cells in autoimmune diabetes. Images Figure 1 Figure 2 PMID:1902627

  2. Hormonal contraceptives, menstrual cycle and brain response to faces

    PubMed Central

    Marečková, Klara; Perrin, Jennifer S.; Nawaz Khan, Irum; Lawrence, Claire; Dickie, Erin; McQuiggan, Doug A.

    2014-01-01

    Both behavioral and neuroimaging evidence support a female advantage in the perception of human faces. Here we explored the possibility that this relationship may be partially mediated by female sex hormones by investigating the relationship between the brain’s response to faces and the use of oral contraceptives, as well as the phase of the menstrual cycle. First, functional magnetic resonance images were acquired in 20 young women [10 freely cycling and 10 taking oral contraception (OC)] during two phases of their cycle: mid-cycle and menstruation. We found stronger neural responses to faces in the right fusiform face area (FFA) in women taking oral contraceptives (vs freely cycling women) and during mid-cycle (vs menstruation) in both groups. Mean blood oxygenation level-dependent response in both left and right FFA increased as function of the duration of OC use. Next, this relationship between the use of OC and FFA response was replicated in an independent sample of 110 adolescent girls. Finally in a parallel behavioral study carried out in another sample of women, we found no evidence of differences in the pattern of eye movements while viewing faces between freely cycling women vs those taking oral contraceptives. The imaging findings might indicate enhanced processing of social cues in women taking OC and women during mid-cycle. PMID:23175677

  3. Hormonal contraceptives, menstrual cycle and brain response to faces.

    PubMed

    Marecková, Klara; Perrin, Jennifer S; Nawaz Khan, Irum; Lawrence, Claire; Dickie, Erin; McQuiggan, Doug A; Paus, Tomás

    2014-02-01

    Both behavioral and neuroimaging evidence support a female advantage in the perception of human faces. Here we explored the possibility that this relationship may be partially mediated by female sex hormones by investigating the relationship between the brain's response to faces and the use of oral contraceptives, as well as the phase of the menstrual cycle. First, functional magnetic resonance images were acquired in 20 young women [10 freely cycling and 10 taking oral contraception (OC)] during two phases of their cycle: mid-cycle and menstruation. We found stronger neural responses to faces in the right fusiform face area (FFA) in women taking oral contraceptives (vs freely cycling women) and during mid-cycle (vs menstruation) in both groups. Mean blood oxygenation level-dependent response in both left and right FFA increased as function of the duration of OC use. Next, this relationship between the use of OC and FFA response was replicated in an independent sample of 110 adolescent girls. Finally in a parallel behavioral study carried out in another sample of women, we found no evidence of differences in the pattern of eye movements while viewing faces between freely cycling women vs those taking oral contraceptives. The imaging findings might indicate enhanced processing of social cues in women taking OC and women during mid-cycle. PMID:23175677

  4. Sympathomimetic pressor responses to thyrotropin-releasing hormone in rats

    SciTech Connect

    Mattila, J.; Bunag, R.D.

    1986-07-01

    Cardiovascular responses to centrally administered thyrotropin-releasing hormone (TRH) were studied in urethan-anesthetized rats to allow continuous recording of attendant changes in sympathetic nerve activity. Intracerebroventricular infusions of TRH consistently increased not only blood pressure and heart rate, but also spike frequency in splanchnic, renal, or cervical sympathetic nerves. Parasympathetic inhibition seemed unlikely because TRH responses were unaltered by cholinergic blockade with atropine, and efferent vagal nerve firing, instead of being reduced, was actually increased by TRH. An increased secretion of endogenous vasopressin also appeared unlikely, since TRH responses were essentially unaffected by either hypophysectomy or pretreatment with a vasopressin antagonist. Inasmuch as pharmacological ganglion blockade with pentolinium eliminated increases in splanchnic nerve firing but reduced the attendant tachycardia by only 50%, residual tachycardia after ganglion blockade was considered partly due to persistent sympathetic cardioaccelerator tone. On the other hand, because pressor responses to TRH were always accompanied by increased sympathetic nerve firing and were completely abolished after pentolinium-induced ganglioplegia, they were attributed solely to sympathetic hyperactivity.

  5. Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus.

    PubMed

    Kryvalap, Yury; Lo, Chi-Wen; Manuylova, Ekaterina; Baldzizhar, Raman; Jospe, Nicholas; Czyzyk, Jan

    2016-01-01

    Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2'-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans. PMID:26578518

  6. Islet formation in mice and men: Lessons for the generation of functional insulin-producing β cells from human pluripotent stem cells

    PubMed Central

    Nair, Gopika; Hebrok, Matthias

    2015-01-01

    The Islets of Langerhans are crucial ‘micro-organs’ embedded in the glandular exocrine pancreas that regulate nutrient metabolism. They not only synthesize, but also secrete endocrine hormones in a modulated fashion in response to physiologic metabolic demand. These highly sophisticated structures with intricate organization of multiple cell types, namely endocrine, vascular, neuronal and mesenchymal cells, have evolved to perform this task to perfection over time. Not surprisingly, islet architecture and function are dissimilar between humans and typically studied model organisms, such as rodents and zebrafish. Further, recent findings also suggest noteworthy differences in human islet development from that in mouse, including delayed appearance and gradual resolution of key differentiation markers, a single-phase of endocrine differentiation, and prenatal association of developing islets with neurovascular milieu. In light of these findings, it is imperative that a systematic study is undertaken to compare islet development between human and mouse. Illuminating inter-species differences in islet development will likely be critical in furthering our pursuit to generate an unlimited supply of truly functional and fully mature β-cells from human pluripotent stem cell (hPSC) sources for therapeutic purposes. PMID:25909383

  7. Islet formation in mice and men: lessons for the generation of functional insulin-producing β-cells from human pluripotent stem cells.

    PubMed

    Nair, Gopika; Hebrok, Matthias

    2015-06-01

    The Islets of Langerhans are crucial 'micro-organs' embedded in the glandular exocrine pancreas that regulate nutrient metabolism. They not only synthesize, but also secrete endocrine hormones in a modulated fashion in response to physiologic metabolic demand. These highly sophisticated structures with intricate organization of multiple cell types, namely endocrine, vascular, neuronal and mesenchymal cells, have evolved to perform this task to perfection over time. Not surprisingly, islet architecture and function are dissimilar between humans and typically studied model organisms, such as rodents and zebrafish. Further, recent findings also suggest noteworthy differences in human islet development from that in mouse, including delayed appearance and gradual resolution of key differentiation markers, a single-phase of endocrine differentiation, and prenatal association of developing islets with neurovascular milieu. In light of these findings, it is imperative that a systematic study is undertaken to compare islet development between human and mouse. Illuminating inter-species differences in islet development will likely be critical in furthering our pursuit to generate an unlimited supply of truly functional and fully mature β-cells from human pluripotent stem cell (hPSC) sources for therapeutic purposes. PMID:25909383

  8. EEG responses in regularly menstruating women and in amenorrheic women treated with ovarian hormones.

    PubMed

    Vogel, W; Broverman, D M; Klaiber, E L

    1971-04-23

    Electroencephalographic driving reponses to photic stimulation vary with the menstrual cycle and with manipulations of ovarian hormones thought to control the menstrual cycle. Estrogens reduce driving responses to photic stimulation, and estrogen plus progesterone enhance these responses. The electroencephalographic changes may reflect the effects of gonadal steroid hormones upon central adrenergic processes. PMID:4323796

  9. Neurohypophyseal Hormone-Responsive Adenylate Cyclase from Mammalian Kidney

    PubMed Central

    Douša, Thomas; Hechter, Oscar; Schwartz, Irving L.; Walter, Roderich

    1971-01-01

    The investigation was undertaken to evaluate the direct stimulatory effects of neurohypophyseal hormones upon adenylate cyclase activity in a cell-free, particulate fraction derived from the kidney medulla of various mammalian species. The relative affinity of neurohypophyseal hormones for the receptor component of the adenylate cyclase system (as defined by the concentration of hormone required for half-maximal stimulation) had the order [8-arginine]-vasopressin > [8-lysine]-vasopressin ≫ oxytocin (AVP > LVP ≫ OT) for rat, mouse, rabbit, and ox; in the pig, the order was LVP > AVP ≫ OT. The relative affinities of the three hormones in rat and pig cyclase systems were found to correspond with the relative antidiuretic potencies of these hormones in the intact rat and pig. These findings show that the renal receptor for neurohypophyseal hormones in a particular species exhibits the highest affinity for the specific antidiuretic hormone that occurs naturally in that species. Some of the molecular requirements for the stimulation of rabbit adenylate cyclase were defined by studies of several neurohypophyseal analogs possessing structural changes in positions 1, 2, 3, 4, 5, 8, and 9. This investigation introduces the particulate preparation of renal medullary adenylate cyclase as a tool for the analysis of neurohypophyseal hormone-receptor interactions and indicates that this preparation can be adapted to serve as an in vitro bioassay system for antidiuretic hormonal activity. PMID:4331557

  10. Extrahepatic islet transplantation with microporous polymer scaffolds in syngeneic mouse and allogeneic porcine models

    PubMed Central

    Gibly, Romie F.; Zhang, Xiaomin; Graham, Melanie L.; Hering, Bernhard J.; Kaufman, Dixon B.; Lowe, William L.; Shea, Lonnie D.

    2011-01-01

    Intraportal transplantation of islets has successfully treated select patients with type 1 diabetes. However, intravascular infusion and the intrahepatic site contribute to significant early and late islet loss, yet a clinical alternative has remained elusive. We investigated non-encapsulating, porous, biodegradable polymer scaffolds as a vehicle for islet transplantation into extrahepatic sites, using syngeneic mouse and allogeneic porcine models. Scaffold architecture was modified to enhance cell infiltration leading to re-vascularization of the islets with minimal inflammatory response. In the diabetic mouse model, 125 islets seeded on scaffolds implanted into the epididymal fat pad restored normoglycemia within an average of 1.95 days and transplantation of only 75 islets required 12.1 days. Increasing the pore size to increase islet-islet interactions did not significantly impact islet function. The porcine model was used to investigate early islet engraftment. Increasing the islet seeding density led to a greater mass of engrafted islets, though the efficiency of islet survival decreased. Transplantation into the porcine omentum provided greater islet engraftment than the gastric submucosa. These results demonstrate scaffolds support murine islet transplantation with high efficiency, and feasibility studies in large animals support continued pre-clinical studies with scaffolds as a platform to control the transplant microenvironment. PMID:21959005

  11. Microfluidic platform for assessing pancreatic islet functionality through dielectric spectroscopy

    PubMed Central

    Heileman, K.; Daoud, J.; Hasilo, C.; Gasparrini, M.; Paraskevas, S.; Tabrizian, M.

    2015-01-01

    Human pancreatic islets are seldom assessed for dynamic responses to external stimuli. Thus, the elucidation of human islet functionality would provide insights into the progression of diabetes mellitus, evaluation of preparations for clinical transplantation, as well as for the development of novel therapeutics. The objective of this study was to develop a microfluidic platform for in vitro islet culture, allowing the multi-parametric investigation of islet response to chemical and biochemical stimuli. This was accomplished through the fabrication and implementation of a microfluidic platform that allowed the perifusion of islet culture while integrating real-time monitoring using impedance spectroscopy, through microfabricated, interdigitated electrodes located along the microchamber arrays. Real-time impedance measurements provide important dielectric parameters, such as cell membrane capacitance and cytoplasmic conductivity, representing proliferation, differentiation, viability, and functionality. The perifusion of varying glucose concentrations and monitoring of the resulting impedance of pancreatic islets were performed as proof-of-concept validation of the lab-on-chip platform. This novel technique to elucidate the underlying mechanisms that dictate islet functionality is presented, providing new information regarding islet function that could improve the evaluation of islet preparations for transplantation. In addition, it will lead to a better understanding of fundamental diabetes-related islet dysfunction and the development of therapeutics through evaluation of potential drug effects. PMID:26339324

  12. Responses of luteinizing hormone, follicle-stimulating hormone, and prolactin to prolonged administration of the dopamine antagonist in normal women and women with low-weight amenorrhea.

    PubMed

    Larsen, S

    1981-06-01

    The responses of luteinizing hormone, follicle-stimulating hormone, and prolactin to prolonged administration of the dopamine receptor antagonist metoclopramide (5 mg twice daily) were investigated in six normal women and six women with low-weight amenorrhea (LWA). In contrast to the normal group, the LWA group showed no significant changes in the mean basal prolactin level or the mean prolactin response to stimulation with thyrotropin-releasing hormone, but there was an significant elevation of the mean net increase in luteinizing hormone after stimulation with gonadotropin-releasing hormone. On the basis of these data, the possibility of increased central dopaminergic activity in women with LWA is discussed. PMID:6788608

  13. Luteinizing hormone release and androgen production of avian hybrids in response to luteinizing hormone releasing hormone injection.

    PubMed

    Mathis, G F; Burke, W H; McDougald, L R

    1983-04-01

    The levels of luteinizing hormone (LH) and androgens were measured in sterile avian hybrids. Guinea fowl-chicken and peafowl-guinea fowl hybrids were bled before and after injection with LH- releasing hormone (LHRH). The preinjection LH levels for the guinea fowl-chicken hybrids were below or at the very lower limit of the assay sensitivity and the peafowl-guinea fowl hybrids averaged 1.3 ng/ml. Within 10 min after LHRH injection, LH had increased dramatically in both hybrids and then began to slowly decline. Androgen levels in the guinea fowl-chicken hybrids increased from 16.2 pg/ml to 95.2 pg/ml and continued to increase, reaching 287 pg/ml at the last bleeding 60 min after injection. PMID:6346309

  14. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology.

    PubMed

    Akter, Rehana; Cao, Ping; Noor, Harris; Ridgway, Zachary; Tu, Ling-Hsien; Wang, Hui; Wong, Amy G; Zhang, Xiaoxue; Abedini, Andisheh; Schmidt, Ann Marie; Raleigh, Daniel P

    2016-01-01

    The hormone islet amyloid polypeptide (IAPP, or amylin) plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy. PMID:26649319

  15. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology

    PubMed Central

    Akter, Rehana; Cao, Ping; Noor, Harris; Ridgway, Zachary; Tu, Ling-Hsien; Wang, Hui; Wong, Amy G.; Zhang, Xiaoxue; Abedini, Andisheh; Schmidt, Ann Marie; Raleigh, Daniel P.

    2016-01-01

    The hormone islet amyloid polypeptide (IAPP, or amylin) plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy. PMID:26649319

  16. Artificial islets from hybrid spheroids of three pancreatic cell lines.

    PubMed

    Jo, Y H; Jang, I J; Nemeno, J G; Lee, S; Kim, B Y; Nam, B M; Yang, W; Lee, K M; Kim, H; Takebe, T; Kim, Y S; Lee, J I

    2014-05-01

    Pancreatic islets have been the focus of recent studies exploring the pathologic mechanisms of diabetes mellitus as well as more effective and radical treatments for this disease. Islet transplantation is a promising therapeutic strategy; however, isolation of pancreatic islets for this purpose has been challenging, because the technique is time consuming and technically difficult, and tissue handling can be variable. Pseudo-islets can be used as an alternative to naïve islets, but require cellular sources or artificial materials. In this study, pancreas-derived cells were used to generate pseudo-islets. Because the pancreas is composed of a variety of cell types, namely α cells, β cells, δ cells, and other pancreatic cells that perform different functions, we used 3 different cell lines-NIT-1 (a β-cell line), α TC1 clone 6 (an α-cell line), and TGP52 (a pancreatic epithelial-like cell line)-which we cocultured in nonadhesive culture plates to produce hybrid cellular spheroids. These pseudo-islets had an oval shape and were morphologically similar to naïve islets; additionally, they expressed and secreted the pancreatic hormones insulin, glucagon, and somatostatin, as confirmed by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. The results demonstrate that pseudo-islets that mimic naïve islets can be successfully generated by a coculture method. These artificial islets can potentially be used for in vitro tests related to diabetes mellitus, specifically, in drug discovery or for investigating pathology. Moreover, they can be useful for examining basic questions pertaining to cell-cell interactions and tissue development. PMID:24815150

  17. In vitro differentiation of human adipose tissue-derived stem cells into islet-like clusters promoted by islet neogenesis-associated protein pentadecapeptide.

    PubMed

    Ren, Lili; Chen, Lijuan; Qi, Hui; Li, Furong; Gong, Feili

    2014-01-01

    Human adipose tissue-derived stem cells (hASCs) are considered an ideal tool for the supply of insulin-producing cells to treat diabetes mellitus, with high differentiation efficiency. Islet neogenesis-associated protein (INGAP) is an initiator of islet neogenesis, and the peptide sequence comprising amino acids 104-118, named INGAP pentadecapeptide (INGAP-PP), has been shown to increase β-cell mass in animals and human pathological states. Here, we report a novel 4-step method to promote hASCs to differentiate into islet-like clusters (ILCs) more efficiently by adding INGAP-PP. The hASCs were isolated, purified and differentiated using a 4-step protocol including trichostatin A, INGAP-PP/scrambled peptide (Scrambled-P), dexamethasone, nicotinamide, glucagon-like peptide-1, transforming growth factor β1 and exendin-4. Results showed that ILCs in the INGAP-PP group were more similar to the fresh islets with regard to both size and morphology and expressed significantly higher levels of both insulin and C-peptide than those in the Scrambled-P group. Moreover, the ILCs from the INGAP-PP group secreted higher levels of insulin and C-peptide than those from the Scrambled-P group in response to both a low (5.6 mM) and high (25 mM) glucose challenge and secreted 6 times more hormones under the high-glucose challenge. Real-time PCR and immunocytochemistry showed that ILCs of the INGAP-PP group expressed human pancreatic endocrine hormones and transcription factors. Transplantation of ILCs into diabetic rats partially reversed diabetes and prolonged their life span. In conclusion, the INGAP-PP protocol can efficiently induce hASCs to differentiate into ILCs in vitro, and thus hASCs could be a promising source of cells for transplantation to treat diabetes mellitus. PMID:25471531

  18. Phenotypic integration and independence: Hormones, performance, and response to environmental change

    PubMed Central

    Ketterson, Ellen D.; Atwell, Jonathan W.; McGlothlin, Joel W.

    2009-01-01

    Hormones coordinate the co-expression of behavioral, physiological, and morphological traits, giving rise to correlations among traits and organisms whose parts work well together. This article considers the implications of these hormonal correlations with respect to the evolution of hormone-mediated traits. Such traits can evolve owing to changes in hormone secretion, hormonal affinity for carrier proteins, rates of degradation and conversion, and interaction with target tissues to name a few. Critically, however, we know very little about whether these changes occur independently or in tandem, and thus whether hormones promote the evolution of tight phenotypic integration or readily allow the parts of the phenotype to evolve independently. For example, when selection favors a change in expression of hormonally mediated characters, is that alteration likely to come about through changes in hormone secretion (signal strength), changes in response to a fixed level of secretion (sensitivity of target tissues), or both? At one extreme, if the phenotype is tightly integrated and only the signal responds via selection's action on one or more hormonally mediated traits, adaptive modification may be constrained by past selection for phenotypic integration. Alternatively, response to selection may be facilitated if multivariate selection favors new combinations that can be easily achieved by a change in signal strength. On the other hand, if individual target tissues readily “unplug” from a hormone signal in response to selection, then the phenotype may be seen as a loose confederation that responds on a trait-by-trait basis, easily allowing adaptive modification, although perhaps more slowly than if signal variation were the primary mode of evolutionary response. Studies reviewed here and questions for future research address the relative importance of integration and independence by comparing sexes, individuals, and populations. Most attention is devoted to the

  19. Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets

    NASA Astrophysics Data System (ADS)

    Cappon, Giacomo; Pedersen, Morten Gram

    2016-05-01

    Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the β-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the β-cell population. Surprisingly, functional coupling analysis of calcium responses in β-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation.

  20. Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets.

    PubMed

    Cappon, Giacomo; Pedersen, Morten Gram

    2016-05-01

    Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the β-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the β-cell population. Surprisingly, functional coupling analysis of calcium responses in β-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation. PMID:27249943

  1. A Method for Mouse Pancreatic Islet Isolation and Intracellular cAMP Determination

    PubMed Central

    Neuman, Joshua C.; Truchan, Nathan A.; Joseph, Jamie W.; Kimple, Michelle E.

    2014-01-01

    Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The β-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the β-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on β-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased β-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3H]-thymidine incorporation, protein abundance, and mRNA expression. PMID:24998772

  2. A method for mouse pancreatic islet isolation and intracellular cAMP determination.

    PubMed

    Neuman, Joshua C; Truchan, Nathan A; Joseph, Jamie W; Kimple, Michelle E

    2014-01-01

    Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The β-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the β-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on β-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased β-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3(H)]-thymidine incorporation, protein abundance, and mRNA expression. PMID:24998772

  3. A specific area of olfactory cortex involved in stress hormone responses to predator odours.

    PubMed

    Kondoh, Kunio; Lu, Zhonghua; Ye, Xiaolan; Olson, David P; Lowell, Bradford B; Buck, Linda B

    2016-04-01

    Instinctive reactions to danger are critical to the perpetuation of species and are observed throughout the animal kingdom. The scent of predators induces an instinctive fear response in mice that includes behavioural changes, as well as a surge in blood stress hormones that mobilizes multiple body systems to escape impending danger. How the olfactory system routes predator signals detected in the nose to achieve these effects is unknown. Here we identify a specific area of the olfactory cortex in mice that induces stress hormone responses to volatile predator odours. Using monosynaptic and polysynaptic viral tracers, we found that multiple olfactory cortical areas transmit signals to hypothalamic corticotropin-releasing hormone (CRH) neurons, which control stress hormone levels. However, only one minor cortical area, the amygdalo-piriform transition area (AmPir), contained neurons upstream of CRH neurons that were activated by volatile predator odours. Chemogenetic stimulation of AmPir activated CRH neurons and induced an increase in blood stress hormones, mimicking an instinctive fear response. Moreover, chemogenetic silencing of AmPir markedly reduced the stress hormone response to predator odours without affecting a fear behaviour. These findings suggest that AmPir, a small area comprising <5% of the olfactory cortex, plays a key part in the hormonal component of the instinctive fear response to volatile predator scents. PMID:27001694

  4. Homozygosity for a dominant negative thyroid hormone receptor gene responsible for generalized resistance to thyroid hormone.

    PubMed

    Ono, S; Schwartz, I D; Mueller, O T; Root, A W; Usala, S J; Bercu, B B

    1991-11-01

    Generalized resistance to thyroid hormones (GRTH) commonly results from mutations in the T3-binding domain of the c-erbA beta thyroid hormone receptor gene. We have reported on a novel deletion mutation in c-erbA beta in a kindred, S, with GRTH. One patient from this kindred was the product of a consanguineous union from two affected members and was homozygous for the beta-receptor defect. This patient at 3.5 weeks of age had unprecedented elevations of TSH, free T4, and free T3 (TSH, 389 mU/L; free T4, 330.8 pmol/L; free T3, 82,719 fmol/L). He displayed a complex mixture of tissue-specific hyperthyroidism and hypothyroidism. He had delayed growth (height age, 1 3/12 yr at chronological age 2 9/12 yr) and skeletal maturation (bone age, 4 months), and developmental delay (developmental age, 8 months), but he was quite tachycardic. The homozygous patient of kindred S is markedly different from a recently reported patient with no c-erbA beta-receptor. This difference indicates that a dominant negative form of c-erbA beta in man can inhibit at least some thyroid hormone action mediated by the c-erbA alpha-receptors. PMID:1682340

  5. Islet cell transplantation.

    PubMed

    Srinivasan, P; Huang, G C; Amiel, S A; Heaton, N D

    2007-04-01

    People with type 1 diabetes have normal exocrine pancreatic function, making islet cell rather than whole organ transplantation an attractive option. Achieving insulin independence in type 1 diabetes was the perceived goal of islet cell transplantation. The success of the Edmonton group in achieving this in a selected group of type 1 patients has led to renewed optimism that this treatment could eventually replace whole organ pancreas transplantation. However the long-term results of this treatment indicate that insulin independence is lost with time in a significant proportion of patients, although they may retain glycaemic stability. In this context, the indications for islet cell transplantation, which have evolved over the last 5 years, indicate that the patients who benefit most are those who experience severe hypoglycaemic reactions despite optimal insulin therapy. This review will summarise the history of islet cell transplantation, islet isolation techniques, the transplant procedure, immunosuppressive therapy, indications for islet cell transplantation, current clinical trials, the early UK islet cell transplant experience using the Edmonton protocol, and some of the challenges that lie ahead. PMID:17403947

  6. Hormone response to bidirectional selection on social behavior

    PubMed Central

    Amdam, Gro V.; Page, Robert E.; Fondrk, M. Kim; Brent, Colin S.

    2010-01-01

    Behavior is a quantitative trait determined by multiple genes. Some of these genes may have effects from early development and onward by influencing hormonal systems that are active during different life-stages — leading to complex associations, or suites, of traits. Honey bees (Apis mellifera) have been used extensively in experiments on the genetic and hormonal control of complex social behavior, but the relationships between their early developmental processes and adult behavioral variation are not well understood. Bidirectional selective breeding on social food-storage behavior produced two honey bee strains, each with several sub-lines, that differ in an associated suite of anatomical, physiological, and behavioral traits found in unselected wild type bees. Using these genotypes, we document strain-specific changes during larval, pupal, and early adult life-stages for the central insect hormones juvenile hormone (JH) and ecdysteroids. Strain differences correlate with variation in female reproductive anatomy (ovary size), which can be influenced by JH during development, and with secretion rates of ecdysteroid from the ovaries of adults. Ovary size was previously assigned to the suite of traits of honey bee food-storage behavior. Our findings support that bidirectional selection on honey bee social behavior acted on pleiotropic gene networks. These networks may bias a bee’s adult phenotype by endocrine effects on early developmental processes that regulate variation in reproductive traits. PMID:20883212

  7. Hormone response to bidirectional selection on social behavior.

    PubMed

    Amdam, Gro V; Page, Robert E; Fondrk, M Kim; Brent, Colin S

    2010-01-01

    Behavior is a quantitative trait determined by multiple genes. Some of these genes may have effects from early development and onward by influencing hormonal systems that are active during different life-stages leading to complex associations, or suites, of traits. Honey bees (Apis mellifera) have been used extensively in experiments on the genetic and hormonal control of complex social behavior, but the relationships between their early developmental processes and adult behavioral variation are not well understood. Bidirectional selective breeding on social food-storage behavior produced two honey bee strains, each with several sublines, that differ in an associated suite of anatomical, physiological, and behavioral traits found in unselected wild type bees. Using these genotypes, we document strain-specific changes during larval, pupal, and early adult life-stages for the central insect hormones juvenile hormone (JH) and ecdysteroids. Strain differences correlate with variation in female reproductive anatomy (ovary size), which can be influenced by JH during development, and with secretion rates of ecdysteroid from the ovaries of adults. Ovary size was previously assigned to the suite of traits of honey bee food-storage behavior. Our findings support that bidirectional selection on honey bee social behavior acted on pleiotropic gene networks. These networks may bias a bee's adult phenotype by endocrine effects on early developmental processes that regulate variation in reproductive traits. PMID:20883212

  8. Hypertrophic response of the Association of Thyroid Hormone and Exercise in the Heart of Rats

    PubMed Central

    de Souza, Fernanda Rodrigues; Resende, Elmiro Santos; Lopes, Leandro; Gonçalves, Alexandre; Chagas, Rafaella; Fidale, Thiago; Rodrigues, Poliana

    2014-01-01

    Background Cardiac hypertrophy is a component of cardiac remodeling occurring in response to an increase of the activity or functional overload of the heart. Objective Assess hypertrophic response of the association of thyroid hormone and exercise in the rat heart. Methods We used 37 Wistar rats, male, adults were randomly divided into four groups: control, hormone (TH), exercise (E), thyroid hormone and exercise (H + E); the group received daily hormone levothyroxine sodium by gavage at a dose of 20 μg thyroid hormone/100g body weight, the exercise group took swimming five times a week, with additional weight corresponding to 20% of body weight for six weeks; in group H + E were applied simultaneously TH treatment groups and E. The statistics used was analysis of variance, where appropriate, by Tukey test and Pearson correlation test. Results The T4 was greater in groups TH and H + E. The total weight of the heart was greater in patients who received thyroid hormone and left ventricular weight was greater in the TH group. The transverse diameter of cardiomyocytes increased in groups TH, E and H + E. The percentage of collagen was greater in groups E and H + E Correlation analysis between variables showed distinct responses. Conclusion The association of thyroid hormone with high-intensity exercise produced cardiac hypertrophy, and generated a standard hypertrophy not directly correlated to the degree of fibrosis. PMID:24676374

  9. 2,4,6-Tribromophenol Interferes with the Thyroid Hormone System by Regulating Thyroid Hormones and the Responsible Genes in Mice.

    PubMed

    Lee, Dongoh; Ahn, Changhwan; Hong, Eui-Ju; An, Beum-Soo; Hyun, Sang-Hwan; Choi, Kyung-Chul; Jeung, Eui-Bae

    2016-01-01

    2,4,6-Tribromophenol (TBP) is a brominated flame retardant (BFR). Based on its affinity for transthyretin, TBP could compete with endogenous thyroid hormone. In this study, the effects of TBP on the thyroid hormone system were assessed in mice. Briefly, animals were exposed to 40 and 250 mg/kg TBP. Thyroid hormones were also administered with or without TBP. When mice were treated with TBP, deiodinase 1 (Dio1) and thyroid hormone receptor β isoform 2 (Thrβ2) decreased in the pituitary gland. The levels of deiodinase 2 (Dio2) and growth hormone (Gh) mRNA increased in response to 250 mg/kg of TBP, and the relative mRNA level of thyroid stimulating hormone β (Tshβ) increased in the pituitary gland. Dio1 and Thrβ1 expression in the liver were not altered, while Dio1 decreased in response to co-treatment with thyroid hormones. The thyroid gland activity decreased in response to TBP, as did the levels of free triiodothyronine and free thyroxine in serum. Taken together, these findings indicate that TBP can disrupt thyroid hormone homeostasis and the presence of TBP influenced thyroid actions as regulators of gene expression. These data suggest that TBP interferes with thyroid hormone systems. PMID:27420076

  10. 2,4,6-Tribromophenol Interferes with the Thyroid Hormone System by Regulating Thyroid Hormones and the Responsible Genes in Mice

    PubMed Central

    Lee, Dongoh; Ahn, Changhwan; Hong, Eui-Ju; An, Beum-Soo; Hyun, Sang-Hwan; Choi, Kyung-Chul; Jeung, Eui-Bae

    2016-01-01

    2,4,6-Tribromophenol (TBP) is a brominated flame retardant (BFR). Based on its affinity for transthyretin, TBP could compete with endogenous thyroid hormone. In this study, the effects of TBP on the thyroid hormone system were assessed in mice. Briefly, animals were exposed to 40 and 250 mg/kg TBP. Thyroid hormones were also administered with or without TBP. When mice were treated with TBP, deiodinase 1 (Dio1) and thyroid hormone receptor β isoform 2 (Thrβ2) decreased in the pituitary gland. The levels of deiodinase 2 (Dio2) and growth hormone (Gh) mRNA increased in response to 250 mg/kg of TBP, and the relative mRNA level of thyroid stimulating hormone β (Tshβ) increased in the pituitary gland. Dio1 and Thrβ1 expression in the liver were not altered, while Dio1 decreased in response to co-treatment with thyroid hormones. The thyroid gland activity decreased in response to TBP, as did the levels of free triiodothyronine and free thyroxine in serum. Taken together, these findings indicate that TBP can disrupt thyroid hormone homeostasis and the presence of TBP influenced thyroid actions as regulators of gene expression. These data suggest that TBP interferes with thyroid hormone systems PMID:27420076

  11. Cardiovascular and hormonal (aldosterone) responses in a rat model which mimics responses to weightlessness

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, J. M.

    1984-01-01

    Cardiovascular responses and fluid/electrolyte shifts seen during spaceflight have been attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended, head-down tilt of 15-20 deg) is used to model these responses. This study documents that elevated blood pressures in AO rats are sustained for periods of up to seven days, compared with presuspension values. Increased blood pressures in AO rats suggests a specific response to AO positioning, potentially relatable to a cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured. Circulating aldosterone concentrations were seen to increase approximately 100 percent during seven days of AO suspension, concurrently with a pronounced natriuresis. These results suggest that aldosterone may not be involved in the long term regulation of increased Na(+) excretion in AO animals. These studies continue to show the usefulness of models for the development of animal protocols for space flight.

  12. Mechanistic Contributions of Biological Cofactors in Islet Amyloid Polypeptide Amyloidogenesis

    PubMed Central

    Nguyen, Phuong Trang; Andraka, Nagore; De Carufel, Carole Anne; Bourgault, Steve

    2015-01-01

    Type II diabetes mellitus is associated with the deposition of fibrillar aggregates in pancreatic islets. The major protein component of islet amyloids is the glucomodulatory hormone islet amyloid polypeptide (IAPP). Islet amyloid fibrils are virtually always associated with several biomolecules, including apolipoprotein E, metals, glycosaminoglycans, and various lipids. IAPP amyloidogenesis has been originally perceived as a self-assembly homogeneous process in which the inherent aggregation propensity of the peptide and its local concentration constitute the major driving forces to fibrillization. However, over the last two decades, numerous studies have shown a prominent role of amyloid cofactors in IAPP fibrillogenesis associated with the etiology of type II diabetes. It is increasingly evident that the biochemical microenvironment in which IAPP amyloid formation occurs and the interactions of the polypeptide with various biomolecules not only modulate the rate and extent of aggregation, but could also remodel the amyloidogenesis process as well as the structure, toxicity, and stability of the resulting fibrils. PMID:26576436

  13. Increased islet apoptosis in Pdx1+/– mice

    PubMed Central

    Johnson, James D.; Ahmed, Noreen T.; Luciani, Dan S.; Han, Zhiqiang; Tran, Hung; Fujita, Jun; Misler, Stanley; Edlund, Helena; Polonsky, Kenneth S.

    2003-01-01

    Mice with 50% Pdx1, a homeobox gene critical for pancreatic development, had worsening glucose tolerance with age and reduced insulin release in response to glucose, KCl, and arginine from the perfused pancreas. Surprisingly, insulin secretion in perifusion or static incubation experiments in response to glucose and other secretagogues was similar in islets isolated from Pdx1+/– mice compared with Pdx1+/+ littermate controls. Glucose sensing and islet Ca2+ responses were also normal. Depolarization-evoked exocytosis and Ca2+ currents in single Pdx1+/– cells were not different from controls, arguing against a ubiquitous β cell stimulus-secretion coupling defect. However, isolated Pdx1+/– islets and dispersed β cells were significantly more susceptible to apoptosis at basal glucose concentrations than Pdx1+/+ islets. BclXL and Bcl-2 expression were reduced in Pdx1+/– islets. In vivo, increased apoptosis was associated with abnormal islet architecture, positive TUNEL, active caspase-3, and lymphocyte infiltration. Although similar in young mice, both β cell mass and islet number failed to increase with age and were approximately 50% less than controls by one year. These results suggest that an increase in apoptosis, with abnormal regulation of islet number and β cell mass, represents a key mechanism whereby partial PDX1 deficiency leads to an organ-level defect in insulin secretion and diabetes. PMID:12697734

  14. Pancreatic Islet Transplantation

    MedlinePlus

    ... researchers at the University of Alberta in Edmonton, Canada, reported their findings in the New England Journal ... transplantation as therapeutic. In other countries, such as Canada and Scandinavia, islet allo-transplantation is no longer ...

  15. Islet Cell Transplantation

    MedlinePlus

    ... It is an experimental treatment for type 1 diabetes. In type 1 diabetes, the beta cells of the pancreas no longer make insulin. A person who has type 1 diabetes must take insulin daily to live. Transplanted islet ...

  16. Fetal endocannabinoids orchestrate the organization of pancreatic islet microarchitecture

    PubMed Central

    Malenczyk, Katarzyna; Keimpema, Erik; Piscitelli, Fabiana; Calvigioni, Daniela; Björklund, Peyman; Mackie, Kenneth; Di Marzo, Vincenzo; Hökfelt, Tomas G. M.; Dobrzyn, Agnieszka; Harkany, Tibor

    2015-01-01

    Endocannabinoids are implicated in the control of glucose utilization and energy homeostasis by orchestrating pancreatic hormone release. Moreover, in some cell niches, endocannabinoids regulate cell proliferation, fate determination, and migration. Nevertheless, endocannabinoid contributions to the development of the endocrine pancreas remain unknown. Here, we show that α cells produce the endocannabinoid 2-arachidonoylglycerol (2-AG) in mouse fetuses and human pancreatic islets, which primes the recruitment of β cells by CB1 cannabinoid receptor (CB1R) engagement. Using subtractive pharmacology, we extend these findings to anandamide, a promiscuous endocannabinoid/endovanilloid ligand, which impacts both the determination of islet size by cell proliferation and α/β cell sorting by differential activation of transient receptor potential cation channel subfamily V member 1 (TRPV1) and CB1Rs. Accordingly, genetic disruption of TRPV1 channels increases islet size whereas CB1R knockout augments cellular heterogeneity and favors insulin over glucagon release. Dietary enrichment in ω-3 fatty acids during pregnancy and lactation in mice, which permanently reduces endocannabinoid levels in the offspring, phenocopies CB1R−/− islet microstructure and improves coordinated hormone secretion. Overall, our data mechanistically link endocannabinoids to cell proliferation and sorting during pancreatic islet formation, as well as to life-long programming of hormonal determinants of glucose homeostasis. PMID:26494286

  17. Fetal endocannabinoids orchestrate the organization of pancreatic islet microarchitecture.

    PubMed

    Malenczyk, Katarzyna; Keimpema, Erik; Piscitelli, Fabiana; Calvigioni, Daniela; Björklund, Peyman; Mackie, Kenneth; Di Marzo, Vincenzo; Hökfelt, Tomas G M; Dobrzyn, Agnieszka; Harkany, Tibor

    2015-11-10

    Endocannabinoids are implicated in the control of glucose utilization and energy homeostasis by orchestrating pancreatic hormone release. Moreover, in some cell niches, endocannabinoids regulate cell proliferation, fate determination, and migration. Nevertheless, endocannabinoid contributions to the development of the endocrine pancreas remain unknown. Here, we show that α cells produce the endocannabinoid 2-arachidonoylglycerol (2-AG) in mouse fetuses and human pancreatic islets, which primes the recruitment of β cells by CB1 cannabinoid receptor (CB1R) engagement. Using subtractive pharmacology, we extend these findings to anandamide, a promiscuous endocannabinoid/endovanilloid ligand, which impacts both the determination of islet size by cell proliferation and α/β cell sorting by differential activation of transient receptor potential cation channel subfamily V member 1 (TRPV1) and CB1Rs. Accordingly, genetic disruption of TRPV1 channels increases islet size whereas CB1R knockout augments cellular heterogeneity and favors insulin over glucagon release. Dietary enrichment in ω-3 fatty acids during pregnancy and lactation in mice, which permanently reduces endocannabinoid levels in the offspring, phenocopies CB1R(-/-) islet microstructure and improves coordinated hormone secretion. Overall, our data mechanistically link endocannabinoids to cell proliferation and sorting during pancreatic islet formation, as well as to life-long programming of hormonal determinants of glucose homeostasis. PMID:26494286

  18. Induction of Protective Genes Leads to Islet Survival and Function

    PubMed Central

    Wang, Hongjun; Ferran, Christiane; Attanasio, Chiara; Calise, Fulvio; Otterbein, Leo E.

    2011-01-01

    Islet transplantation is the most valid approach to the treatment of type 1 diabetes. However, the function of transplanted islets is often compromised since a large number of β cells undergo apoptosis induced by stress and the immune rejection response elicited by the recipient after transplantation. Conventional treatment for islet transplantation is to administer immunosuppressive drugs to the recipient to suppress the immune rejection response mounted against transplanted islets. Induction of protective genes in the recipient (e.g., heme oxygenase-1 (HO-1), A20/tumor necrosis factor alpha inducible protein3 (tnfaip3), biliverdin reductase (BVR), Bcl2, and others) or administration of one or more of the products of HO-1 to the donor, the islets themselves, and/or the recipient offers an alternative or synergistic approach to improve islet graft survival and function. In this perspective, we summarize studies describing the protective effects of these genes on islet survival and function in rodent allogeneic and xenogeneic transplantation models and the prevention of onset of diabetes, with emphasis on HO-1, A20, and BVR. Such approaches are also appealing to islet autotransplantation in patients with chronic pancreatitis after total pancreatectomy, a procedure that currently only leads to 1/3 of transplanted patients being diabetes-free. PMID:22220267

  19. Thrombomodulin Improves Early Outcomes After Intraportal Islet Transplantation

    PubMed Central

    Cui, W.; Wilson, J. T.; Wen, J.; Angsana, J.; Qu, Z.; Haller, C. A.; Chaikof, E. L.

    2009-01-01

    Primary islet nonfunction due to an instant blood mediated inflammatory reaction (IBMIR) leads to an increase in donor islet mass required to achieve euglycemia. In the presence of thrombin, thrombomodulin generates activated protein C (APC), which limits procoagulant and proinflammatory responses. In this study, we postulated that liposomal formulations of thrombomodulin (lipo-TM), due to its propensity for preferential uptake in the liver, would enhance intraportal engraftment of allogeneic islets by inhibiting the IBMIR. Diabetic C57BL/6J mice underwent intraportal transplantation with B10.BR murine islets. In the absence of treatment, conversion to euglycemia was observed among 29% of mice receiving 250 allo-islets. In contrast, a single infusion of lipo-TM led to euglycemia in 83% of recipients (p = 0.0019). Fibrin deposition (p< 0.0001), neutrophil infiltration (p < 0.0001), as well as expression TNF-α and IL-β (p<0.03)were significantly reduced. Significantly, thrombotic responses mediated by human islets in contact with human blood were also reduced by this approach. Lipo-TM improves the engraftment of allogeneic islets through a reduction in local thrombotic and inflammatory processes. As an enzyme-based pharmacotherapeutic, this strategy offers the potential for local generation of APC at the site of islet infusion, during the initial period of elevated thrombin production. PMID:19459803

  20. Amyloid in the islets of Langerhans: thoughts and some historical aspects.

    PubMed

    Westermark, Per

    2011-05-01

    Deposition of amyloid, derived from the polypeptide hormone islet amyloid polypeptide (IAPP; 'amylin') is the single most typical islet alteration in type 2 diabetes. Islet amyloid was described as hyalinization already in 1901, but not until 1986 was it understood that it is a polymerization product of a novel β-cell regulatory product. The subject of this focused review deals with the pathogenesis and importance of the islet amyloid itself, not with the biological effect of the polypeptide. Similar to the situation in Alzheimer's disease, it has been argued that the amyloid may not be of importance since there is no strict correlation between the degree of islet amyloid infiltration and the disease. However, it is hardly discussable that the amyloid is important in subjects where islets have been destroyed by pronounced islet amyloid deposits. Even when there is less islet amyloid the deposits are widely spread, and β-cells show ultrastructural signs of cell membrane destruction. It is suggested that type 2 diabetes is heterogeneous and that in one major subtype aggregation of IAPP into amyloid fibrils is determining the progressive loss of β-cells. Interestingly, development of islet amyloid may be an important event in the loss of β-cell function after islet transplantation into type 1 diabetic subjects. PMID:21486192

  1. Amyloid in the islets of Langerhans: Thoughts and some historical aspects

    PubMed Central

    2011-01-01

    Deposition of amyloid, derived from the polypeptide hormone islet amyloid polypeptide (IAPP; ‘amylin’) is the single most typical islet alteration in type 2 diabetes. Islet amyloid was described as hyalinization already in 1901, but not until 1986 was it understood that it is a polymerization product of a novel β-cell regulatory product. The subject of this focused review deals with the pathogenesis and importance of the islet amyloid itself, not with the biological effect of the polypeptide. Similar to the situation in Alzheimer's disease, it has been argued that the amyloid may not be of importance since there is no strict correlation between the degree of islet amyloid infiltration and the disease. However, it is hardly discussable that the amyloid is important in subjects where islets have been destroyed by pronounced islet amyloid deposits. Even when there is less islet amyloid the deposits are widely spread, and β-cells show ultrastructural signs of cell membrane destruction. It is suggested that type 2 diabetes is heterogeneous and that in one major subtype aggregation of IAPP into amyloid fibrils is determining the progressive loss of β-cells. Interestingly, development of islet amyloid may be an important event in the loss of β-cell function after islet transplantation into type 1 diabetic subjects. PMID:21486192

  2. Asymmetrical distribution of δ and PP cells in human pancreatic islets.

    PubMed

    Barbieux, Charlotte; Parnaud, Géraldine; Lavallard, Vanessa; Brioudes, Estelle; Meyer, Jérémy; Alibashe Ahmed, Mohamed; Berishvili, Ekaterine; Berney, Thierry; Bosco, Domenico

    2016-05-01

    The aim of this study was to evaluate the location of PP and δ cells in relation to the vascularization within human pancreatic islets. To this end, pancreas sections were analysed by immunofluorescence using antibodies against endocrine islet and endothelial cells. Staining in different islet areas corresponding to islet cells adjacent or not to peripheral or central vascular channels was quantified by computerized morphometry. As results, α, PP and δ cells were preferentially found adjacent to vessels. In contrast to α cells, which were evenly distributed between islet periphery and intraislet vascular channels, PP and δ cells had asymmetric and opposite distributions: PP staining was higher and somatostatin staining was lower in the islet periphery than in the area around intraislet vascular channels. Additionally, frequencies of PP and δ cells were negatively correlated in the islets. No difference was observed between islets from the head and the tail of the pancreas, and from type 2 diabetic and non-diabetic donors. In conclusion, the distribution of δ cells differs from that of PP cells in human islets, suggesting that vessels at the periphery and at the centre of islets drain different hormonal cocktails. PMID:26931137

  3. Infection of human islets of Langerhans with two strains of Coxsackie B virus serotype 1: assessment of virus replication, degree of cell death and induction of genes involved in the innate immunity pathway.

    PubMed

    Anagandula, Mahesh; Richardson, Sarah J; Oberste, M Steven; Sioofy-Khojine, Amir-Babak; Hyöty, Heikki; Morgan, Noel G; Korsgren, Olle; Frisk, Gun

    2014-08-01

    Type 1 diabetes mellitus is believed to be triggered, in part, by one or more environmental factors and human enteroviruses (HEVs) are among the candidates. Therefore, this study has examined whether two strains of HEV may differentially affect the induction of genes involved in pathways leading to the synthesis of islet hormones, chemokines and cytokines in isolated, highly purified, human islets. Isolated, purified human pancreatic islets were infected with strains of Coxsackievirus B1.Viral replication and the degree of CPE/islet dissociation were monitored. The expression of insulin, glucagon, CXCL10, TLR3, IF1H1, CCL5, OAS-1, IFNβ, and DDX58 was analyzed. Both strains replicated in islets but only one of strain caused rapid islet dissociation/CPE. Expression of the insulin gene was reduced during infection of islets with either viral strain but the gene encoding glucagon was unaffected. All genes analyzed which are involved in viral sensing and the development of innate immunity were induced by Coxsackie B viruses, with the notable exception of TLR3. There was no qualitative difference in the expression pattern between each strain but the magnitude of the response varied between donors. The lack of virus induced expression of TLR3, together with the differential regulation of IF1H1, OAS1 and IFNβ, (each of which has polymorphic variants influence the predisposition to type 1 diabetes), that might result in defective clearance of virus from islet cells. The reduced expression of the insulin gene and the unaffected expression of the gene encoding glucagon by Coxsackie B1 infection is consistent with the preferential β-cell tropism of the virus. PMID:24249667

  4. Role of various hormones in photosynthetic responses of green plants under environmental stresses.

    PubMed

    Poonam; Bhardwaj, Renu; Kaur, Ravdeep; Bali, Shagun; Kaur, Parminder; Sirhindi, Geetika; Thukral, Ashwani K; Ohri, Puja; Vig, Adarsh P

    2015-01-01

    Environmental stress includes adverse factors like water deficit, high salinity, enhanced temperature and heavy metals etc. These stresses alter the normal growth and metabolic processes of plants including photosynthesis. Major photosynthetic responses under various stresses include inhibition of photosystems (I and II), changes in thylakoid complexes, decreased photosynthetic activity and modifications in structure and functions of chloroplasts etc. Various defense mechanisms are triggered inside the plants in response to these stresses that are regulated by plant hormones or plant growth regulators. These phytohormones include abscisic acid, auxins, cytokinins, ethylene, brassinosteroids, jasmonates and salicylic acid etc. The present review focuses on stress protective effects of plants hormones on the photosynthetic responses. PMID:25824389

  5. Sexual dimorphism of stress response and immune/ inflammatory reaction: the corticotropin releasing hormone perspective

    PubMed Central

    Vamvakopoulos, Nicholas V.

    1995-01-01

    This review higlghts key aspects of corticotropin releasing hormone (CRH) biology of potential relevance to the sexual dimorphism of the stress response and immune/inflammatory reaction, and introduces two important new concepts based on the regulatory potential of the human (h) CRH gene: (1) a proposed mechanism to account for the tissue-specific antithetical responses of hCRH gene expression to glucocorticolds, that may also explain the frequently observed antithetical effects of chronic glucocorticoid administration in clinical practice and (2) a heuristic diagram to illustrate the proposed modulation of the stress response and immune/ inflammatory reaction by steroid hormones, from the perspective of the CRH system. PMID:18475634

  6. Predicting the Probability of Abnormal Stimulated Growth Hormone Response in Children After Radiotherapy for Brain Tumors

    SciTech Connect

    Hua Chiaho; Wu Shengjie; Chemaitilly, Wassim; Lukose, Renin C.; Merchant, Thomas E.

    2012-11-15

    Purpose: To develop a mathematical model utilizing more readily available measures than stimulation tests that identifies brain tumor survivors with high likelihood of abnormal growth hormone secretion after radiotherapy (RT), to avoid late recognition and a consequent delay in growth hormone replacement therapy. Methods and Materials: We analyzed 191 prospectively collected post-RT evaluations of peak growth hormone level (arginine tolerance/levodopa stimulation test), serum insulin-like growth factor 1 (IGF-1), IGF-binding protein 3, height, weight, growth velocity, and body mass index in 106 children and adolescents treated for ependymoma (n = 72), low-grade glioma (n = 28) or craniopharyngioma (n = 6), who had normal growth hormone levels before RT. Normal level in this study was defined as the peak growth hormone response to the stimulation test {>=}7 ng/mL. Results: Independent predictor variables identified by multivariate logistic regression with high statistical significance (p < 0.0001) included IGF-1 z score, weight z score, and hypothalamic dose. The developed predictive model demonstrated a strong discriminatory power with an area under the receiver operating characteristic curve of 0.883. At a potential cutoff point of probability of 0.3 the sensitivity was 80% and specificity 78%. Conclusions: Without unpleasant and expensive frequent stimulation tests, our model provides a quantitative approach to closely follow the growth hormone secretory capacity of brain tumor survivors. It allows identification of high-risk children for subsequent confirmatory tests and in-depth workup for diagnosis of growth hormone deficiency.

  7. Psychological response to growth hormone treatment in short normal children.

    PubMed Central

    Downie, A B; Mulligan, J; McCaughey, E S; Stratford, R J; Betts, P R; Voss, L D

    1996-01-01

    This study provides a controlled assessment of the psychological (and physical) effects of growth hormone treatment. Fifteen short 'normal' children (height SD score < -2) have been treated with growth hormone since the age of 7/8 years. They, together with untreated short controls and average controls (10th-90th centiles), were assessed at recruitment, after three years, and after five years. Only the treated group showed a significant height increase (SD score -2.44 to -1.21 over five years). No significant differences were found at recruitment, three years, or five years in IQ, attainment, behaviour, or self esteem. Also at five years, there were no significant differences in locus of control, self perception, or parental perceptions of competence. Both short groups displayed less satisfaction with their height than the controls (p < 0.01), though all groups were optimistic of being tall adults. The treated children were no more unrealistic over final height than the untreated children. To date, no psychological benefits of treatment have been demonstrated; but nor have there been any discernible ill effects for either the treated or the untreated children. PMID:8813867

  8. Pancreatic Ductal Perfusion at Organ Procurement Enhances Islet Yield in Human Islet Isolation

    PubMed Central

    Shimoda, Masayuki; Kanak, Mazhar A.; Shahbazov, Rauf; Kunnathodi, Faisal; Lawrence, Michael C.; Naziruddin, Bashoo; Levy, Marlon F.

    2015-01-01

    Objective Pancreas preservation is a major factor influencing the results of islet cell transplantation. This study evaluated the effects of two different solutions for pancreatic ductal perfusion (PDP) at organ procurement. Methods Eighteen human pancreases were assigned to three groups: non-PDP (control), PDP with ET-Kyoto solution, and PDP with cold storage/purification stock solution. Pancreatic islets were isolated according to the modified Ricordi method. Results No significant differences in donor characteristics, including cold ischemia time, were observed between the three groups. All islet isolations in the PDP groups had >400,000 IEQ in total islet yield post-purification, a significant increase when compared with the control (P = 0.04 and <0.01). The islet quality assessments—including an in vivo diabetic nude mice assay and the response of high-mobility group box protein 1 to cytokine stimulation—also showed no significant differences. The proportion of TUNEL-positive cells showing apoptosis in islets in the PDP groups was significantly lower than in the control group (P < 0.05). Conclusion Both ET-Kyoto solution and cold storage/purification stock solution are suitable for PDP and consistently resulted in isolation success. Further studies with a larger number of pancreas donors should be done to compare the effects of the PDP solutions. PMID:25058879

  9. Hormonal Responses to Cholinergic Input Are Different in Humans with and without Type 2 Diabetes Mellitus

    PubMed Central

    Dunai, Judit; Kilpatrick, Rachel; Oestricker, Lauren Z.; Wallendorf, Michael J.; Patterson, Bruce W.; Reeds, Dominic N.; Wice, Burton M.

    2016-01-01

    Peripheral muscarinic acetylcholine receptors regulate insulin and glucagon release in rodents but their importance for similar roles in humans is unclear. Bethanechol, an acetylcholine analogue that does not cross the blood-brain barrier, was used to examine the role of peripheral muscarinic signaling on glucose homeostasis in humans with normal glucose tolerance (NGT; n = 10), impaired glucose tolerance (IGT; n = 11), and type 2 diabetes mellitus (T2DM; n = 9). Subjects received four liquid meal tolerance tests, each with a different dose of oral bethanechol (0, 50, 100, or 150 mg) given 60 min before a meal containing acetaminophen. Plasma pancreatic polypeptide (PP), glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucose, glucagon, C-peptide, and acetaminophen concentrations were measured. Insulin secretion rates (ISRs) were calculated from C-peptide levels. Acetaminophen and PP concentrations were surrogate markers for gastric emptying and cholinergic input to islets. The 150 mg dose of bethanechol increased the PP response 2-fold only in the IGT group, amplified GLP-1 release in the IGT and T2DM groups, and augmented the GIP response only in the NGT group. However, bethanechol did not alter ISRs or plasma glucose, glucagon, or acetaminophen concentrations in any group. Prior studies showed infusion of xenin-25, an intestinal peptide, delays gastric emptying and reduces GLP-1 release but not ISRs when normalized to plasma glucose levels. Analysis of archived plasma samples from this study showed xenin-25 amplified postprandial PP responses ~4-fold in subjects with NGT, IGT, and T2DM. Thus, increasing postprandial cholinergic input to islets augments insulin secretion in mice but not humans. Trial Registration: ClinicalTrials.gov NCT01434901 PMID:27304975

  10. Automated separation of merged Langerhans islets

    NASA Astrophysics Data System (ADS)

    Švihlík, Jan; Kybic, Jan; Habart, David

    2016-03-01

    This paper deals with separation of merged Langerhans islets in segmentations in order to evaluate correct histogram of islet diameters. A distribution of islet diameters is useful for determining the feasibility of islet transplantation in diabetes. First, the merged islets at training segmentations are manually separated by medical experts. Based on the single islets, the merged islets are identified and the SVM classifier is trained on both classes (merged/single islets). The testing segmentations were over-segmented using watershed transform and the most probable back merging of islets were found using trained SVM classifier. Finally, the optimized segmentation is compared with ground truth segmentation (correctly separated islets).

  11. Influence of hormonal contraceptives on the pituitary response to LH/FSH-releasing hormone.

    PubMed

    Carol, W; Lauterbach, H; Klinger, G; Möller, R

    1978-03-01

    In the pre-ovulatory phase the absolute and relative LH increase was much greater than during the luteal phase and less pronounced in the early follicular phase of the normal cycle. FSH release was affected only during the pre-ovulatory period, where a retarded, 3- or 4-fold increase compared to basal levels was recorded. In the women taking oral contraceptives of the conventional type the first LH-RH test showed gonadotropin responses similar to those obtained during the luteal phase of the controls. The second test brought a significantly lower LH response, suggesting an increasing exogenous steroid inhibition at the pituitary level in the course of the therapeutic cycle. This inhibition seems to be reversed during the monthly tablet-free interval. A particularly small and retarded gonadotropin response was observed in patients taking Deposiston. These results are discussed as to their clinical significance. PMID:357145

  12. How plants handle multiple stresses: hormonal interactions underlying responses to abiotic stress and insect herbivory.

    PubMed

    Nguyen, Duy; Rieu, Ivo; Mariani, Celestina; van Dam, Nicole M

    2016-08-01

    Adaptive plant responses to specific abiotic stresses or biotic agents are fine-tuned by a network of hormonal signaling cascades, including abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid. Moreover, hormonal cross-talk modulates plant responses to abiotic stresses and defenses against insect herbivores when they occur simultaneously. How such interactions affect plant responses under multiple stresses, however, is less understood, even though this may frequently occur in natural environments. Here, we review our current knowledge on how hormonal signaling regulates abiotic stress responses and defenses against insects, and discuss the few recent studies that attempted to dissect hormonal interactions occurring under simultaneous abiotic stress and herbivory. Based on this we hypothesize that drought stress enhances insect resistance due to synergistic interactions between JA and ABA signaling. Responses to flooding or waterlogging involve ethylene signaling, which likely reduces plant resistance to chewing herbivores due to its negative cross-talk with JA. However, the outcome of interactions between biotic and abiotic stress signaling is often plant and/or insect species-dependent and cannot simply be predicted based on general knowledge on the involvement of signaling pathways in single stress responses. More experimental data on non-model plant and insect species are needed to reveal general patterns and better understand the molecular mechanisms allowing plants to optimize their responses in complex environments. PMID:27095445

  13. Adaptation of pancreatic islet cyto-architecture during development

    NASA Astrophysics Data System (ADS)

    Striegel, Deborah A.; Hara, Manami; Periwal, Vipul

    2016-04-01

    Plasma glucose in mammals is regulated by hormones secreted by the islets of Langerhans embedded in the exocrine pancreas. Islets consist of endocrine cells, primarily α, β, and δ cells, which secrete glucagon, insulin, and somatostatin, respectively. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Varying demands and available nutrients during development produce changes in the local connectivity of β cells in an islet. We showed in earlier work that graph theory provides a framework for the quantification of the seemingly stochastic cyto-architecture of β cells in an islet. To quantify the dynamics of endocrine connectivity during development requires a framework for characterizing changes in the probability distribution on the space of possible graphs, essentially a Fokker-Planck formalism on graphs. With large-scale imaging data for hundreds of thousands of islets containing millions of cells from human specimens, we show that this dynamics can be determined quantitatively. Requiring that rearrangement and cell addition processes match the observed dynamic developmental changes in quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that there is a transient shift in preferred connectivity for β cells between 1–35 weeks and 12–24 months.

  14. Adaptation of pancreatic islet cyto-architecture during development.

    PubMed

    Striegel, Deborah A; Hara, Manami; Periwal, Vipul

    2016-01-01

    Plasma glucose in mammals is regulated by hormones secreted by the islets of Langerhans embedded in the exocrine pancreas. Islets consist of endocrine cells, primarily α, β, and δ cells, which secrete glucagon, insulin, and somatostatin, respectively. β cells form irregular locally connected clusters within islets that act in concert to secrete insulin upon glucose stimulation. Varying demands and available nutrients during development produce changes in the local connectivity of β cells in an islet. We showed in earlier work that graph theory provides a framework for the quantification of the seemingly stochastic cyto-architecture of β cells in an islet. To quantify the dynamics of endocrine connectivity during development requires a framework for characterizing changes in the probability distribution on the space of possible graphs, essentially a Fokker-Planck formalism on graphs. With large-scale imaging data for hundreds of thousands of islets containing millions of cells from human specimens, we show that this dynamics can be determined quantitatively. Requiring that rearrangement and cell addition processes match the observed dynamic developmental changes in quantitative topological graph characteristics strongly constrained possible processes. Our results suggest that there is a transient shift in preferred connectivity for β cells between 1-35 weeks and 12-24 months. PMID:27063927

  15. Identification of thyroid hormone response elements in vivo using mice expressing a tagged thyroid hormone receptor α1

    PubMed Central

    Dudazy-Gralla, Susi; Nordström, Kristina; Hofmann, Peter Josef; Meseh, Dina Abdul; Schomburg, Lutz; Vennström, Björn; Mittag, Jens

    2013-01-01

    TRα1 (thyroid hormone receptor α1) is well recognized for its importance in brain development. However, due to the difficulties in predicting TREs (thyroid hormone response elements) in silico and the lack of suitable antibodies against TRα1 for ChIP (chromatin immunoprecipitation), only a few direct TRα1 target genes have been identified in the brain. Here we demonstrate that mice expressing a TRα1–GFP (green fluorescent protein) fusion protein from the endogenous TRα locus provide a valuable animal model to identify TRα1 target genes. To this end, we analysed DNA–TRα1 interactions in vivo using ChIP with an anti-GFP antibody. We validated our system using established TREs from neurogranin and hairless, and by verifying additional TREs from known TRα1 target genes in brain and heart. Moreover, our model system enabled the identification of novel TRα1 target genes such as RNF166 (ring finger protein 166). Our results demonstrate that transgenic mice expressing a tagged nuclear receptor constitute a feasible approach to study receptor–DNA interactions in vivo, circumventing the need for specific antibodies. Models like the TRα1–GFP mice may thus pave the way for genome-wide mapping of nuclear receptor-binding sites, and advance the identification of novel target genes in vivo. PMID:23398480

  16. Composition and function of macroencapsulated human embryonic stem cell-derived implants: comparison with clinical human islet cell grafts.

    PubMed

    Motté, Evi; Szepessy, Edit; Suenens, Krista; Stangé, Geert; Bomans, Myriam; Jacobs-Tulleneers-Thevissen, Daniel; Ling, Zhidong; Kroon, Evert; Pipeleers, Daniel

    2014-11-01

    β-Cells generated from large-scale sources can overcome current shortages in clinical islet cell grafts provided that they adequately respond to metabolic variations. Pancreatic (non)endocrine cells can develop from human embryonic stem (huES) cells following in vitro derivation to pancreatic endoderm (PE) that is subsequently implanted in immune-incompetent mice for further differentiation. Encapsulation of PE increases the proportion of endocrine cells in subcutaneous implants, with enrichment in β-cells when they are placed in TheraCyte-macrodevices and predominantly α-cells when they are alginate-microencapsulated. At posttransplant (PT) weeks 20-30, macroencapsulated huES implants presented higher glucose-responsive plasma C-peptide levels and a lower proinsulin-over-C-peptide ratio than human islet cell implants under the kidney capsule. Their ex vivo analysis showed the presence of single-hormone-positive α- and β-cells that exhibited rapid secretory responses to increasing and decreasing glucose concentrations, similar to isolated human islet cells. However, their insulin secretory amplitude was lower, which was attributed in part to a lower cellular hormone content; it was associated with a lower glucose-induced insulin biosynthesis, but not with lower glucagon-induced stimulation, which together is compatible with an immature functional state of the huES-derived β-cells at PT weeks 20-30. These data support the therapeutic potential of macroencapsulated huES implants but indicate the need for further functional analysis. Their comparison with clinical-grade human islet cell grafts sets references for future development and clinical translation. PMID:25205822

  17. Central stimulation of hormone release and the proliferative response of lymphocytes in humans.

    PubMed

    Juránková, E; Jezová, D; Vigas, M

    1995-01-01

    The central nervous system (CNS) may communicate with the immune system by direct innervation of lymphoid organs and/or by neurotransmitters and changes in neuroendocrine functioning and hormone release. The consequences of selective transient changes in circulating hormones on immune functioning in humans have not yet been studied. To address this problem, the authors evaluated the lymphoproliferative responses to optimal and suboptimal concentrations of phytohemagglutinin (PHA) and pokeweek mitogen (PWM) under selective enhancement of circulating growth hormone, prolactin, or norepinephrine. The authors failed to demonstrate any effect of elevated growth hormone levels after clonidine challenge on the lymphoproliferative response to mitogens. Similarly, the results did not show any effect of elevated prolactin concentrations induced by domperidone administration on the immune test. Exposure of volunteers to cold resulted in elevation of plasma norepinephrine levels without changes in growth hormone, epinephrine, or cortisol secretion. Cold exposure induced elevation of plasma norepinephrine and reduction of the lymphoproliferative response to the suboptimal dosage of PHA. The reduction was significant 180 and 240 min after exposure. These results are indicative of a relationship between norepinephrine and immunity. PMID:8534322

  18. A Hormone-responsive 3D Culture Model of the Human Mammary Gland Epithelium.

    PubMed

    Speroni, Lucia; Sweeney, Michael F; Sonnenschein, Carlos; Soto, Ana M

    2016-01-01

    The process of mammary epithelial morphogenesis is influenced by hormones. The study of hormone action on the breast epithelium using 2D cultures is limited to cell proliferation and gene expression endpoints. However, in the organism, mammary morphogenesis occurs in a 3D environment. 3D culture systems help bridge the gap between monolayer cell culture (2D) and the complexity of the organism. Herein, we describe a 3D culture model of the human breast epithelium that is suitable to study hormone action. It uses the commercially available hormone-responsive human breast epithelial cell line, T47D, and rat tail collagen type 1 as a matrix. This 3D culture model responds to the main mammotropic hormones: estradiol, progestins and prolactin. The influence of these hormones on epithelial morphogenesis can be observed after 1- or 2-week treatment according to the endpoint. The 3D cultures can be harvested for analysis of epithelial morphogenesis, cell proliferation and gene expression. PMID:26891095

  19. Differential Responses to Steroid Hormones in Fibroblasts From the Vocal Fold, Trachea, and Esophagus

    PubMed Central

    Mukudai, Shigeyuki; Matsuda, Ken Ichi; Nishio, Takeshi; Sugiyama, Yoichiro; Bando, Hideki; Hirota, Ryuichi; Sakaguchi, Hirofumi; Hisa, Yasuo

    2015-01-01

    There is accumulating evidence that fibroblasts are target cells for steroids such as sex hormones and corticoids. The characteristics of fibroblasts vary among tissues and organs. Our aim in this study is to examine differences in responses to steroid hormones among fibroblasts from different cervicothoracic regions. We compared the actions of steroid hormones on cultured fibroblasts from the vocal folds, which are considered to be the primary target of steroid hormones, and the trachea and esophagus in adult male rats. Expression of steroid hormone receptors (androgen receptor, estrogen receptor α, and glucocorticoid receptor) was identified by immunofluorescence histochemistry. Androgen receptor was much more frequently expressed in fibroblasts from the vocal fold than in those from the trachea and esophagus. Cell proliferation analysis showed that administration of testosterone, estradiol, or corticosterone suppressed growth of all 3 types of fibroblasts. However, mRNA expression for extracellular matrix–associated genes, including procollagen I and III and elastin, and hyaluronic acid synthase I was elevated only by addition of testosterone to fibroblasts from the vocal fold. These results indicate that each steroid hormone exerts region-specific effects on cervicothoracic fibroblasts with different properties through binding to specific receptors. PMID:25514085

  20. The Nutrient-Responsive Hormone CCHamide-2 Controls Growth by Regulating Insulin-like Peptides in the Brain of Drosophila melanogaster.

    PubMed

    Sano, Hiroko; Nakamura, Akira; Texada, Michael J; Truman, James W; Ishimoto, Hiroshi; Kamikouchi, Azusa; Nibu, Yutaka; Kume, Kazuhiko; Ida, Takanori; Kojima, Masayasu

    2015-05-01

    The coordination of growth with nutritional status is essential for proper development and physiology. Nutritional information is mostly perceived by peripheral organs before being relayed to the brain, which modulates physiological responses. Hormonal signaling ensures this organ-to-organ communication, and the failure of endocrine regulation in humans can cause diseases including obesity and diabetes. In Drosophila melanogaster, the fat body (adipose tissue) has been suggested to play an important role in coupling growth with nutritional status. Here, we show that the peripheral tissue-derived peptide hormone CCHamide-2 (CCHa2) acts as a nutrient-dependent regulator of Drosophila insulin-like peptides (Dilps). A BAC-based transgenic reporter revealed strong expression of CCHa2 receptor (CCHa2-R) in insulin-producing cells (IPCs) in the brain. Calcium imaging of brain explants and IPC-specific CCHa2-R knockdown demonstrated that peripheral-tissue derived CCHa2 directly activates IPCs. Interestingly, genetic disruption of either CCHa2 or CCHa2-R caused almost identical defects in larval growth and developmental timing. Consistent with these phenotypes, the expression of dilp5, and the release of both Dilp2 and Dilp5, were severely reduced. Furthermore, transcription of CCHa2 is altered in response to nutritional levels, particularly of glucose. These findings demonstrate that CCHa2 and CCHa2-R form a direct link between peripheral tissues and the brain, and that this pathway is essential for the coordination of systemic growth with nutritional availability. A mammalian homologue of CCHa2-R, Bombesin receptor subtype-3 (Brs3), is an orphan receptor that is expressed in the islet β-cells; however, the role of Brs3 in insulin regulation remains elusive. Our genetic approach in Drosophila melanogaster provides the first evidence, to our knowledge, that bombesin receptor signaling with its endogenous ligand promotes insulin production. PMID:26020940

  1. The Nutrient-Responsive Hormone CCHamide-2 Controls Growth by Regulating Insulin-like Peptides in the Brain of Drosophila melanogaster

    PubMed Central

    Sano, Hiroko; Nakamura, Akira; Texada, Michael J.; Truman, James W.; Ishimoto, Hiroshi; Kamikouchi, Azusa; Nibu, Yutaka; Kume, Kazuhiko; Ida, Takanori; Kojima, Masayasu

    2015-01-01

    The coordination of growth with nutritional status is essential for proper development and physiology. Nutritional information is mostly perceived by peripheral organs before being relayed to the brain, which modulates physiological responses. Hormonal signaling ensures this organ-to-organ communication, and the failure of endocrine regulation in humans can cause diseases including obesity and diabetes. In Drosophila melanogaster, the fat body (adipose tissue) has been suggested to play an important role in coupling growth with nutritional status. Here, we show that the peripheral tissue-derived peptide hormone CCHamide-2 (CCHa2) acts as a nutrient-dependent regulator of Drosophila insulin-like peptides (Dilps). A BAC-based transgenic reporter revealed strong expression of CCHa2 receptor (CCHa2-R) in insulin-producing cells (IPCs) in the brain. Calcium imaging of brain explants and IPC-specific CCHa2-R knockdown demonstrated that peripheral-tissue derived CCHa2 directly activates IPCs. Interestingly, genetic disruption of either CCHa2 or CCHa2-R caused almost identical defects in larval growth and developmental timing. Consistent with these phenotypes, the expression of dilp5, and the release of both Dilp2 and Dilp5, were severely reduced. Furthermore, transcription of CCHa2 is altered in response to nutritional levels, particularly of glucose. These findings demonstrate that CCHa2 and CCHa2-R form a direct link between peripheral tissues and the brain, and that this pathway is essential for the coordination of systemic growth with nutritional availability. A mammalian homologue of CCHa2-R, Bombesin receptor subtype-3 (Brs3), is an orphan receptor that is expressed in the islet β-cells; however, the role of Brs3 in insulin regulation remains elusive. Our genetic approach in Drosophila melanogaster provides the first evidence, to our knowledge, that bombesin receptor signaling with its endogenous ligand promotes insulin production. PMID:26020940

  2. Hormone naïve prostate cancer: predicting and maximizing response intervals

    PubMed Central

    Moul, Judd W

    2015-01-01

    Hormone naïve advanced prostate cancer is subdivided into two disease states: biochemical recurrence and traditional M1 (metastatic) prostate cancer and characterized by no prior hormonal therapy or androgen deprivation therapy (ADT). In biochemical recurrence/prostate-specific antigen (PSA) recurrence, men should be risk-stratified based on their PSA doubling time, the Gleason score and the timing of the recurrence. In general, only men who are at high risk should be considered for early/immediate ADT although this is best done using shared decision with the patient. The type of ADT to be used in biochemical recurrence ranging from oral-only peripheral blockade (peripheral androgen deprivation) to complete hormonal therapy (combined androgen blockade [CAB]) remains in debate owing to lack of randomized controlled trials (RCT). However, there is good RCT support for use of intermittent hormonal therapy (IHT). There is also limited research on biomarker response (PSA and testosterone decline) to predict prognosis. On the other hand, in the setting of M1 hormone naïve prostate cancer, there are many more RCT's to inform our decisions. CAB and gonadotrophin-releasing hormone antagonists perhaps provide a slight efficacy advantage while IHT may be slightly inferior with minimal M1 disease. The PSA nadir at 7 months after starting ADT is a powerful prognostic tool for M1 patients. There is growing recognition that serum testosterone (T) control while on ADT is linked to the development of castrate-resistant prostate cancer. Especially for a M1 patient, maintaining a serum T below 20–30 ng dl−1 prolongs the response to ADT. Novel oral agents (abiraterone and enzalutamide) may soon find use in hormone naïve disease and may alter the treatment landscape. Despite over 75 years of experience with ADT, many questions remain, and the field continues to evolve. PMID:26112479

  3. Hormone response element binding proteins: novel regulators of vitamin D and estrogen signaling

    PubMed Central

    Lisse, Thomas S.; Hewison, Martin; Adams, John S.

    2011-01-01

    Insights from vitamin D-resistant New World primates and their human homologues as models of natural and pathological insensitivity to sterol/steroid action have uncovered a family of novel intracellular vitamin D and estrogen regulatory proteins involved in hormone action. The proteins, known as “vitamin D or estrogen response element-binding proteins”, behave as potent cis-acting, transdominant regulators to inhibit steroid receptor binding to DNA response elements and is responsible for vitamin D and estrogen resistances. This set of interactors belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) family of previously known pre-mRNA-interacting proteins. This review provides new insights into the mechanism by which these novel regulators of signaling and metabolism can act to regulate responses to vitamin D and estrogen. In addition the review also describes other molecules that are known to influence nuclear receptor signaling through interaction with hormone response elements. PMID:21236284

  4. Somatostatin and counterregulatory hormone responses to hypoglycaemia in diabetics with and without autonomic neuropathy.

    PubMed

    Fernandez-Castaner, M; Webb, S; Levy, I; Rios, M; Casamitjana, R; Bergua, M; Figuerola, D; Rivera, F

    1985-04-01

    Blood glucose, somatostatin and counterregulatory hormone responses to an i.v. bolus of insulin were studied in insulin-dependent diabetics with different degrees of autonomic neuropathy, after 24 hours of optimised control with an artificial pancreas. There was no plasma catecholamine response in patients with a sympathetic autonomic neuropathy. A normal somatostatin response to hypoglycemia was absent in patients with autonomic neuropathy. Glucagon did not respond in diabetics, independently of the degree of neuropathy. In all diabetics, cortisol and GH were stimulated. Absence of warning symptoms was observed in patients with catecholamine deficiency. Despite different hormone behaviour, blood glucose fall and recovery were similar in all diabetic groups. It is concluded that the glucagon response to insulin hypoglycaemia is reduced in all type 1 longstanding diabetics, whereas catecholamine and somatostatin responses are only abolished in those with autonomic neuropathy. Patients with sympathetic neuropathy would be considered at increased risk severe hypoglycaemia. PMID:2861121

  5. Placental insufficiency decreases pancreatic vascularity and disrupts hepatocyte growth factor signaling in the pancreatic islet endothelial cell in fetal sheep.

    PubMed

    Rozance, Paul J; Anderson, Miranda; Martinez, Marina; Fahy, Anna; Macko, Antoni R; Kailey, Jenai; Seedorf, Gregory J; Abman, Steven H; Hay, William W; Limesand, Sean W

    2015-02-01

    Hepatocyte growth factor (HGF) and vascular endothelial growth factor A (VEGFA) are paracrine hormones that mediate communication between pancreatic islet endothelial cells (ECs) and β-cells. Our objective was to determine the impact of intrauterine growth restriction (IUGR) on pancreatic vascularity and paracrine signaling between the EC and β-cell. Vessel density was less in IUGR pancreata than in controls. HGF concentrations were also lower in islet EC-conditioned media (ECCM) from IUGR, and islets incubated with control islet ECCM responded by increasing insulin content, which was absent with IUGR ECCM. The effect of ECCM on islet insulin content was blocked with an inhibitory anti-HGF antibody. The HGF receptor was not different between control and IUGR islets, but VEGFA was lower and the high-affinity VEGF receptor was higher in IUGR islets and ECs, respectively. These findings show that paracrine actions from ECs increase islet insulin content, and in IUGR ECs, secretion of HGF was diminished. Given the potential feed-forward regulation of β-cell VEGFA and islet EC HGF, these two growth factors are highly integrated in normal pancreatic islet development, and this regulation is decreased in IUGR fetuses, resulting in lower pancreatic islet insulin concentrations and insulin secretion. PMID:25249573

  6. Endoscopic biopsy of islet transplants in the gastric submucosal space provides evidence of islet graft rejection in diabetic pigs.

    PubMed

    Tanaka, Takayuki; Fujita, Minoru; Bottino, Rita; Piganelli, Jon D; McGrath, Kevin; Li, Jiang; Lee, Whayoung; Iwase, Hayato; Wijkstrom, Martin; Bertera, Suzanne; Long, Cassandra; Landsittel, Douglas; Haruma, Ken; Cooper, David K C; Hara, Hidetaka

    2016-01-01

    Transplantation of islets into the gastric submucosal space (GSMS) has several advantages (e.g., avoidance of the instant blood-mediated inflammatory response [IBMIR], ability to biopsy). The aim of this study was to determine whether endoscopic biopsy of islet allografts transplanted into the GSMS in diabetic pigs can provide histopathological and immunohistochemical information that correlates with the clinical course (e.g.,, blood glucose level, insulin requirement). Islet allografts (Group1: 10,000 kIEq /kg [n = 4]; Group2: 15,000 kIEq /kg [n = 2]) were transplanted into the GSMS of diabetic pigs under immunosuppression. In Group2, the anti-oxidant, BMX-001 was applied during preservation, isolation, and culture of the islets, and at the time of transplantation. Endoscopic biopsies of the islet grafts were obtained one or 2 weeks after transplantation, and histopathological features were compared with the clinical course (e.g., blood glucose, insulin requirement). In Group1, in the absence of anti-oxidant therapy, most of the islets became fragmented, and there was no reduction in exogenous insulin requirement. In Group2, with an increased number of transplanted islets in the presence of BMX-001, more healthy insulin-positive islet masses were obtained at biopsy and necropsy (4 weeks), and these correlated with reductions in both blood glucose level and insulin requirement. In all cases, inflammatory cell infiltrates were present. After islet transplantation into the GSMS, endoscopic biopsy can provide information on graft rejection, which would be an immense advantage in clinical islet transplantation. PMID:26857703

  7. Growth Hormone Effects in Immune Stress: AKT/eNOS Signaling Module in the Cellular Response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The activation of the constitutive endothelial nitric-oxide synthase (eNOS) and expression of inducible NOS (iNOS) with subsequent nitric oxide production are among the early cellular responses that follow in a systemic exposure of animals to lipopolysaccharide (LPS). Growth hormone (GH) has been sh...

  8. NEONATAL SYMPATHECTOMY COMPROMISES DEVELOPMENT OF RESPONSES OF ORNITHINE DECARBOXYLASE TO HORMONAL STIMULATION IN PERIPHERAL TISSUES

    EPA Science Inventory

    The onset of sympathetic innervation has been shown to play a role in the development of postsynaptic reactivity to stimulation. n the current study, we examined whether this relationship extends to responses evoked by hormonal stimuli. ats denervated at birth by 6-hydroxydopamin...

  9. HPA-Axis Hormone Modulation of Stress Response Circuitry Activity in Women with Remitted Major Depression

    PubMed Central

    Holsen, Laura M.; Lancaster, Katie; Klibanski, Anne; Whitfield-Gabrieli, Susan; Cherkerzian, Sara; Buka, Stephen; Goldstein, Jill M.

    2013-01-01

    Decades of clinical and basic research indicate significant links between altered hypothalamic-pituitary-adrenal (HPA)-axis hormone dynamics and major depressive disorder (MDD). Recent neuroimaging studies of MDD highlight abnormalities in stress response circuitry regions which play a role in the regulation of the HPA-axes. However, there is a dearth of research examining these systems in parallel, especially as related to potential trait characteristics. The current study addresses this gap by investigating neural responses to a mild visual stress challenge with real-time assessment of adrenal hormones in women with MDD in remission and controls. 15 women with recurrent MDD in remission (rMDD) and 15 healthy control women were scanned on a 3T Siemens MR scanner while viewing neutral and negative (stress-evoking) stimuli. Blood samples were obtained before, during, and after scanning for measurement of HPA-axis hormone levels. Compared to controls, rMDD women demonstrated higher anxiety ratings, increased cortisol levels, and hyperactivation in the amygdala and hippocampus, p<0.05, FWE-corrected in response to the stress challenge. Among rMDD women, amygdala activation was negatively related to cortisol changes and positively associated with duration of remission. Findings presented here provide evidence for differential effects of altered HPA-axis hormone dynamics on hyperactivity in stress response circuitry regions elicited by a well-validated stress paradigm in women with recurrent MDD in remission. PMID:23891965

  10. Responses of sex steroid hormones to different intensities of exercise in endurance athletes.

    PubMed

    Sato, Koji; Iemitsu, Motoyuki; Katayama, Keisho; Ishida, Koji; Kanao, Yoji; Saito, Mitsuru

    2016-01-01

    Previous studies have shown that acute exercise elevates sex steroid hormone concentrations in rodents and that sprint exercise increases circulating testosterone in healthy young men. However, the effect of different exercise intensities on sex steroid hormone responses at different levels of physical fitness is still unclear. In this study, we compared circulating sex steroid hormone responses at different exercise intensities in athletes and non-athletes. Eight male endurance athletes and 11 non-athletes performed two 15 min sessions of submaximal exercise at 40 and 70% peak oxygen uptake (V̇(O2peak)), respectively, and exercised at 90% V̇(O2peak) until exhaustion. Venous blood samples were collected during the last minute of each submaximal exercise session and immediately after exhaustion. Acute exercise at 40, 70 and 90% V̇(O2peak) induced significant increases in serum dehydroepiandrosterone (DHEA) and free testosterone concentrations in non-athletes. On the contrary, only 90% V̇O2 peak exercise led to an increase in serum DHEA and free testosterone concentrations in athletes. Serum 5α-dihydrotestosterone concentrations increased with 90% V̇(O2peak) exercise in both athletes and non-athletes. Additionally, serum estradiol concentrations were significantly increased at moderate and high exercise intensities in both athletes and non-athletes. These results indicate that in endurance athletes, serum sex steroid hormone concentrations, especially serum DHEA and 5α-dihydrotestosterone concentrations, increased only with high-intensity exercise, suggesting that different responses of sex steroid hormone secretion are induced by different exercise intensities in individuals with low and high levels of physical fitness. In athletes, therefore, high-intensity exercise may be required to increase circulating sex steroid hormone concentrations. PMID:26518151

  11. Engineering Biomimetic Materials for Islet Transplantation

    PubMed Central

    Yang, Ethan Y.; Kronenfeld, Joshua P.; Stabler, Cherie L.

    2015-01-01

    A closed-loop system that provides both the sensing of glucose and the appropriate dosage of insulin could dramatically improve treatment options for insulin-dependent diabetics. The intrahepatic implantation of allogeneic islets has the potential to provide this intimate control, by transplanting the very cells that have this inherent sensing and secretion capacity. Limiting islet transplantation, however, is the significant loss and dysfunction of islets following implantation, due to the poor engraftment environment and significant immunological attack. In this review, we outline approaches that seek to address these challenges via engineering biomimetic materials. These materials can serve to mimic natural processes that work toward improving engraftment, minimizing inflammation, and directing immunological responses. Biomimetic materials can serve to house cells, recapitulate native microenvironments, release therapeutic agents in a physiological manner, and/or present agents to direct cells towards desired responses. By integrating these approaches, superior platforms capable of improving long-term engraftment and acceptance of transplanted islets are on the horizon. PMID:25776871

  12. Prolactin and growth hormone responses to hypoglycemia in patients with systemic sclerosis and psoriatic arthritis.

    PubMed

    Rovensky, Jozef; Raffayova, Helena; Imrich, Richard; Radikova, Zofia; Penesova, Adela; Macho, Ladislav; Lukac, Jozef; Matucci-Cerinic, Marco; Vigas, Milan

    2006-06-01

    This study compared prolactin (PRL) and growth hormone (GH) responses to hypoglycemia in premenopausal females with systemic sclerosis (SSc) and psoriatic arthritis (PsA) with those in matched healthy controls. No differences were found in glucose and GH responses to hypoglycemia in both groups of patients compared to controls. SSc patients had lower PRL response (P < 0.05) to hypoglycemia compared to controls. PRL response tended to be lower also in PsA patients, however the difference did not reach level of statistical significance (P = 0.11). The present study showed decreased PRL response to hypoglycemia in premenopausal females with SSc. PMID:16855141

  13. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    SciTech Connect

    Xia, Bing; Zhan, Xiao-Rong; Yi, Ran; Yang, Baofeng

    2009-06-12

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing {beta}-cells. The functional mass of {beta}-cells is decreased in type 1 diabetes, so replacing missing {beta}-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the {beta}-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding {beta}-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet {beta}-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal cells as

  14. Characterisation of the Xenogeneic Immune Response to Microencapsulated Fetal Pig Islet-Like Cell Clusters Transplanted into Immunocompetent C57BL/6 Mice

    PubMed Central

    Ratnapala, Sabina; Foster, Jayne; Vaghjiani, Vijesh; Manuelpillai, Ursula; Tuch, Bernard E.

    2013-01-01

    Xenotransplantation of microencapsulated fetal pig islet-like cell clusters (FP ICCs) offers a potential cellular therapy for type 1 diabetes. Although microcapsules prevent direct contact of the host immune system with the xenografted tissue, poor graft survival is still an issue. This study aimed to characterise the nature of the host immune cells present on the engrafted microcapsules and effects on encapsulated FP ICCs that were transplanted into immunocompetent mice. Encapsulated FP ICCs were transplanted into the peritoneal cavity of C57BL/6 mice. Grafts retrieved at days 1, 3, 7, 14 and 21 post-transplantation were analysed for pericapsular fibrotic overgrowth (PFO), cell viability, intragraft porcine gene expression, macrophages, myofibroblasts and intraperitoneal murine cytokines. Graft function was assessed ex vivo by insulin secretion studies. Xenogeneic immune response to encapsulated FP ICCs was associated with enhanced intragraft mRNA expression of porcine antigens MIP-1α, IL-8, HMGB1 and HSP90 seen within the first two weeks post-transplantation. This was associated with the recruitment of host macrophages, infiltration of myofibroblasts and collagen deposition leading to PFO which was evident from day 7 post-transplantation. This was accompanied by a decrease in cell viability and loss of FP ICC architecture. The only pro-inflammatory cytokine detected in the murine peritoneal flushing was TNF-α with levels peaking at day 7 post transplantation. This correlated with the onset of PFO at day 7 implying activated macrophages as its source. The anti-inflammatory cytokines detected were IL-5 and IL-4 with levels peaking at days 1 and 7, respectively. Porcine C-peptide was undetectable at all time points post-transplantation. PFO was absent and murine intraperitoneal cytokines were undetectable when empty microcapsules were transplanted. In conclusion, this study demonstrated that the macrophages are direct effectors of the xenogeneic immune response to

  15. Small Molecule Inhibited Parathyroid Hormone Mediated cAMP Response by N–Terminal Peptide Binding

    PubMed Central

    Kumar, Amit; Baumann, Monika; Balbach, Jochen

    2016-01-01

    Ligand binding to certain classes of G protein coupled receptors (GPCRs) stimulates the rapid synthesis of cAMP through G protein. Human parathyroid hormone (PTH), a member of class B GPCRs, binds to its receptor via its N–terminal domain, thereby activating the pathway to this secondary messenger inside cells. Presently, GPCRs are the target of many pharmaceuticals however, these drugs target only a small fraction of structurally known GPCRs (about 10%). Coordination complexes are gaining interest due to their wide applications in the medicinal field. In the present studies we explored the potential of a coordination complex of Zn(II) and anthracenyl–terpyridine as a modulator of the parathyroid hormone response. Preferential interactions at the N–terminal domain of the peptide hormone were manifested by suppressed cAMP generation inside the cells. These observations contribute a regulatory component to the current GPCR–cAMP paradigm, where not the receptor itself, but the activating hormone is a target. To our knowledge, this is the first report about a coordination complex modulating GPCR activity at the level of deactivating its agonist. Developing such molecules might help in the control of pathogenic PTH function such as hyperparathyroidism, where control of excess hormonal activity is essentially required. PMID:26932583

  16. A Hormone-Responsive C1-Domain-Containing Protein At5g17960 Mediates Stress Response in Arabidopsis thaliana

    PubMed Central

    Bhaskar, Ravindran Vijay; Mohanty, Bijayalaxmi; Verma, Vivek; Wijaya, Edward; Kumar, Prakash P.

    2015-01-01

    Phytohormones play a critical role in mediating plant stress response. They employ a variety of proteins for coordinating such processes. In Arabidopsis thaliana, some members of a Cys-rich protein family known as C1-clan proteins were involved in stress response, but the actual function of the protein family is largely unknown. We studied At5g17960, a C1-clan protein member that possesses three unique C1 signature domains viz. C1_2, C1_3 and ZZ/PHD type. Additionally, we identified 72 other proteins in A. thaliana that contain all three unique signature domains. Subsequently, the 73 proteins were phylogenetically classified into IX subgroups. Promoter motif analysis of the 73 genes identified the presence of hormone-responsive and stress-responsive putative cis-regulatory elements. Furthermore, we observed that transcript levels of At5g17960 were induced in response to different hormones and stress treatments. At1g35610 and At3g13760, two other members of subgroup IV, also showed upregulation upon GA3, biotic and abiotic stress treatments. Moreover, seedlings of independent transgenic A. thaliana lines ectopically expressing or suppressing At5g17960 also showed differential regulation of several abiotic stress-responsive marker genes. Thus, our data suggest that C1-domain-containing proteins have a role to play in plant hormone-mediated stress responses, thereby assigning a putative function for the C1-clan protein family. PMID:25590629

  17. Mesobiliverdin IXα Enhances Rat Pancreatic Islet Yield and Function.

    PubMed

    Ito, Taihei; Chen, Dong; Chang, Cheng-Wei Tom; Kenmochi, Takashi; Saito, Tomonori; Suzuki, Satoshi; Takemoto, Jon Y

    2013-01-01

    The aims of this study were to produce mesobiliverdin IXα, an analog of anti-inflammatory biliverdin IXα, and to test its ability to enhance rat pancreatic islet yield for allograft transplantation into diabetic recipients. Mesobiliverdin IXα was synthesized from phycocyanobilin derived from cyanobacteria, and its identity and purity were analyzed by chromatographic and spectroscopic methods. Mesobiliverdin IXα was a substrate for human NADPH biliverdin reductase. Excised Lewis rat pancreata infused with mesobiliverdin IXα and biliverdin IXα-HCl (1-100 μM) yielded islet equivalents as high as 86.7 and 36.5%, respectively, above those from non-treated controls, and the islets showed a high degree of viability based on dithizone staining. When transplanted into livers of streptozotocin-induced diabetic rats, islets from pancreata infused with mesobiliverdin IXα lowered non-fasting blood glucose (BG) levels in 55.6% of the recipients and in 22.2% of control recipients. In intravenous glucose tolerance tests, fasting BG levels of 56 post-operative day recipients with islets from mesobiliverdin IXα infused pancreata were lower than those for controls and showed responses that indicate recovery of insulin-dependent function. In conclusion, mesobiliverdin IXα infusion of pancreata enhanced yields of functional islets capable of reversing insulin dysfunction in diabetic recipients. Since its production is scalable, mesobiliverdin IXα has clinical potential as a protectant of pancreatic islets for allograft transplantation. PMID:23630498

  18. Beneficial effects of growth hormone-releasing hormone agonists on rat INS-1 cells and on streptozotocin-induced NOD/SCID mice

    PubMed Central

    Zhang, Xianyang; Cui, Tengjiao; He, Jinlin; Wang, Haibo; Cai, Renzhi; Popovics, Petra; Vidaurre, Irving; Sha, Wei; Schmid, Janine; Ludwig, Barbara; Block, Norman L.; Bornstein, Stefan R.; Schally, Andrew V.

    2015-01-01

    Agonists of growth hormone-releasing hormone (GHRH) have been previously reported to promote growth, function, and engraftment of islet cells following transplantation. Here we evaluated recently synthesized GHRH agonists on the proliferation and biological functions of rat pancreatic β-cell line (INS-1) and islets. In vitro treatment of INS-1 cells with GHRH agonists increased cell proliferation, the expression of cellular insulin, insulin-like growth factor-1 (IGF1), and GHRH receptor, and also stimulated insulin secretion in response to glucose challenge. Exposure of INS-1 cells to GHRH agonists, MR-356 and MR-409, induced activation of ERK and AKT pathways. Agonist MR-409 also significantly increased the levels of cellular cAMP and the phosphorylation of cAMP response element binding protein (CREB) in INS-1 cells. Treatment of rat islets with agonist, MR-409 significantly increased cell proliferation, islet size, and the expression of insulin. In vivo daily s.c. administration of 10 μg MR-409 for 3 wk dramatically reduced the severity of streptozotocin (STZ)-induced diabetes in nonobese diabetic severe combined immunodeficiency (NOD/SCID) mice. The maximal therapeutic benefits with respect to the efficiency of engraftment, ability to reach normoglycemia, gain in body weight, response to high glucose challenge, and induction of higher levels of serum insulin and IGF1 were observed when diabetic mice were transplanted with rat islets preconditioned with GHRH agonist, MR-409, and received additional treatment with MR-409 posttransplantation. This study provides an improved approach to the therapeutic use of GHRH agonists in the treatment of diabetes mellitus. PMID:26474831

  19. Mechanisms of Islet Amyloidosis Toxicity in Type 2 Diabetes

    PubMed Central

    Abedini, Andisheh; Schmidt, Ann Marie

    2014-01-01

    Amyloid formation by the neuropancreatic hormone, islet amyloid polypeptide (IAPP or amylin), one of the most amyloidogenic sequences known, leads to islet amyloidosis in type 2 diabetes and to islet transplant failure. Under normal conditions, IAPP plays a role in the maintenance of energy homeostasis by regulating several metabolic parameters, such as satiety, blood glucose levels, adiposity and body weight. The mechanisms of IAPP amyloid formation, the nature of IAPP toxic species and the cellular pathways that lead to pancreatic β-cell toxicity are not well characterized. Several mechanisms of toxicity, including receptor and non-receptor-mediated events, have been proposed. Analogs of IAPP have been approved for the treatment of diabetes and are under investigation for the treatment of obesity. PMID:23337872

  20. Difference in growth hormone response to growth hormone-releasing hormone (GHRH) testing following GHRH subacute treatment in normal aging and growth hormone-deficient adults: possible perspectives for therapeutic use of GHRH or its analogs in elderly subjects?

    PubMed

    Iovino, M; Triggiani, V; Giagulli, V A; Iovine, N; Licchelli, B; Resta, F; Sabbà, C; Tafaro, E; Solimando, A; Tommasicchio, A; Guastamacchia, E

    2011-06-01

    The somatotroph axis function shows a decline in the elderly (somatopause). In particular growth hormone (GH) response to GH-releasing hormone (GHRH) is reduced in aged man but less than that observed in GH-deficient adults (GHDAs). Plasma GH response to GHRH (1 µg/kg BW) was significantly lower in four GHDAs than in seven healthy aged men 30, 60, and 90 min after acute GHRH administration. To verify whether a priming regimen might be able to increase the reduced GH response to GHRH, both healthy aged men and GHDA patients underwent repetitive administration of GHRH (100 µg GHRH intravenously as a single morning dose, every 2 days for 12 days). After the GHRH-priming regimen, plasma GH values 30, 60, and 90 min after the acute GHRH test were significantly higher than values at the corresponding time points before priming regimen in healthy aged men but not in GHDA patients. These findings confirmed that somatotroph cells become less sensitive to GHRH with normal aging and demonstrate that repetitive administration of GHRH restores the attenuated response only in healthy aged men but not in GHDA patients. This could support the possible use of GHRH or its analogs instead of recombinant human GH in elderly patients with the advantage of preserving the endogenous pulses of GH with the secretion of the different isoforms of GH. However, concerns arise about the possible role of these molecules in tumorigenesis and tumor growth promotion. PMID:20843274

  1. Genetic Architecture of a Hormonal Response to Gene Knockdown in Honey Bees

    PubMed Central

    Rueppell, Olav; Huang, Zachary Y.; Wang, Ying; Fondrk, M. Kim; Page, Robert E.; Amdam, Gro V.

    2015-01-01

    Variation in endocrine signaling is proposed to underlie the evolution and regulation of social life histories, but the genetic architecture of endocrine signaling is still poorly understood. An excellent example of a hormonally influenced set of social traits is found in the honey bee (Apis mellifera): a dynamic and mutually suppressive relationship between juvenile hormone (JH) and the yolk precursor protein vitellogenin (Vg) regulates behavioral maturation and foraging of workers. Several other traits cosegregate with these behavioral phenotypes, comprising the pollen hoarding syndrome (PHS) one of the best-described animal behavioral syndromes. Genotype differences in responsiveness of JH to Vg are a potential mechanistic basis for the PHS. Here, we reduced Vg expression via RNA interference in progeny from a backcross between 2 selected lines of honey bees that differ in JH responsiveness to Vg reduction and measured JH response and ovary size, which represents another key aspect of the PHS. Genetic mapping based on restriction site-associated DNA tag sequencing identified suggestive quantitative trait loci (QTL) for ovary size and JH responsiveness. We confirmed genetic effects on both traits near many QTL that had been identified previously for their effect on various PHS traits. Thus, our results support a role for endocrine control of complex traits at a genetic level. Furthermore, this first example of a genetic map of a hormonal response to gene knockdown in a social insect helps to refine the genetic understanding of complex behaviors and the physiology that may underlie behavioral control in general. PMID:25596612

  2. Optogenetic Control of Pancreatic Islets.

    PubMed

    Reinbothe, Thomas M; Mollet, Inês G

    2016-01-01

    In light of the emerging diabetes epidemic, new experimental approaches in islet research are needed to elucidate the mechanisms behind pancreatic islet dysfunction and to facilitate the development of more effective therapies. Optogenetics has created numerous new experimental tools enabling us to gain insights into processes little was known about before. The spatial and temporal precision that it can achieve is also attractive for studying the cells of the pancreatic islet and we set out to explore the possibilities of this technology for our purposes. We here describe how to use the islets of an "optogenetic beta-cell" mouse line in islet batch incubations and Ca(2+) imaging experiments. This protocol enables light-induced insulin release and provides an all-optical solution to control and measure intracellular Ca(2+) levels in pancreatic beta-cells. The technique is easy to set up and provides a useful tool for controlling the activity of distinct islet cell populations. PMID:26965119

  3. A Combinatorial Protein Microarray for Probing Materials Interaction with Pancreatic Islet Cell Populations.

    PubMed

    Delalat, Bahman; Rojas-Canales, Darling M; Rasi Ghaemi, Soraya; Waibel, Michaela; Harding, Frances J; Penko, Daniella; Drogemuller, Christopher J; Loudovaris, Thomas; Coates, Patrick T H; Voelcker, Nicolas H

    2016-01-01

    Pancreatic islet transplantation has become a recognized therapy for insulin-dependent diabetes mellitus. During isolation from pancreatic tissue, the islet microenvironment is disrupted. The extracellular matrix (ECM) within this space not only provides structural support, but also actively signals to regulate islet survival and function. In addition, the ECM is responsible for growth factor presentation and sequestration. By designing biomaterials that recapture elements of the native islet environment, losses in islet function and number can potentially be reduced. Cell microarrays are a high throughput screening tool able to recreate a multitude of cellular niches on a single chip. Here, we present a screening methodology for identifying components that might promote islet survival. Automated fluorescence microscopy is used to rapidly identify islet derived cell interaction with ECM proteins and immobilized growth factors printed on arrays. MIN6 mouse insulinoma cells, mouse islets and, finally, human islets are progressively screened. We demonstrate the capability of the platform to identify ECM and growth factor protein candidates that support islet viability and function and reveal synergies in cell response. PMID:27600088

  4. PD-L1 Deficiency within Islets Reduces Allograft Survival in Mice

    PubMed Central

    Ma, Dongxia; Duan, Wu; Li, Yakun; Wang, Zhimin; Li, Shanglin; Gong, Nianqiao; Chen, Gang; Chen, Zhishui; Wan, Chidan; Yang, Jun

    2016-01-01

    Background Islet transplantation may potentially cure type 1 diabetes mellitus (T1DM). However, immune rejection, especially that induced by the alloreactive T-cell response, remains a restraining factor for the long-term survival of grafted islets. Programmed death ligand-1 (PD-L1) is a negative costimulatory molecule. PD-L1 deficiency within the donor heart accelerates allograft rejection. Here, we investigate whether PD-L1 deficiency in donor islets reduces allograft survival time. Methods Glucose Stimulation Assays were performed to evaluate whether PD-L1 deficiency has detrimental effects on islet function. Islets isolated from PDL1-deficient mice or wild- type (WT) mice (C57BL/6j) were implanted beneath the renal capsule of streptozotocin (STZ)-induced diabetic BALB/c mice. Blood glucose levels and graft survival time after transplantation were monitored. Moreover, we analyzed the residual islets, infiltrating immune cells and alloreactive cells from the recipients. Results PD-L1 deficiency within islets does not affect islet function. However, islet PD-L1 deficiency increased allograft rejection and was associated with enhanced inflammatory cell infiltration and recipient T-cell alloreactivity. Conclusions This is the first report to demonstrate that PD-L1 deficiency accelerated islet allograft rejection and regulated recipient alloimmune responses. PMID:26990974

  5. AUXIN RESPONSE FACTOR 2 Intersects Hormonal Signals in the Regulation of Tomato Fruit Ripening.

    PubMed

    Breitel, Dario A; Chappell-Maor, Louise; Meir, Sagit; Panizel, Irina; Puig, Clara Pons; Hao, Yanwei; Yifhar, Tamar; Yasuor, Hagai; Zouine, Mohamed; Bouzayen, Mondher; Granell Richart, Antonio; Rogachev, Ilana; Aharoni, Asaph

    2016-03-01

    The involvement of ethylene in fruit ripening is well documented, though knowledge regarding the crosstalk between ethylene and other hormones in ripening is lacking. We discovered that AUXIN RESPONSE FACTOR 2A (ARF2A), a recognized auxin signaling component, functions in the control of ripening. ARF2A expression is ripening regulated and reduced in the rin, nor and nr ripening mutants. It is also responsive to exogenous application of ethylene, auxin and abscisic acid (ABA). Over-expressing ARF2A in tomato resulted in blotchy ripening in which certain fruit regions turn red and possess accelerated ripening. ARF2A over-expressing fruit displayed early ethylene emission and ethylene signaling inhibition delayed their ripening phenotype, suggesting ethylene dependency. Both green and red fruit regions showed the induction of ethylene signaling components and master regulators of ripening. Comprehensive hormone profiling revealed that altered ARF2A expression in fruit significantly modified abscisates, cytokinins and salicylic acid while gibberellic acid and auxin metabolites were unaffected. Silencing of ARF2A further validated these observations as reducing ARF2A expression let to retarded fruit ripening, parthenocarpy and a disturbed hormonal profile. Finally, we show that ARF2A both homodimerizes and interacts with the ABA STRESS RIPENING (ASR1) protein, suggesting that ASR1 might be linking ABA and ethylene-dependent ripening. These results revealed that ARF2A interconnects signals of ethylene and additional hormones to co-ordinate the capacity of fruit tissue to initiate the complex ripening process. PMID:26959229

  6. AUXIN RESPONSE FACTOR 2 Intersects Hormonal Signals in the Regulation of Tomato Fruit Ripening

    PubMed Central

    Meir, Sagit; Panizel, Irina; Puig, Clara Pons; Hao, Yanwei; Yifhar, Tamar; Yasuor, Hagai; Zouine, Mohamed; Bouzayen, Mondher; Granell Richart, Antonio; Rogachev, Ilana; Aharoni, Asaph

    2016-01-01

    The involvement of ethylene in fruit ripening is well documented, though knowledge regarding the crosstalk between ethylene and other hormones in ripening is lacking. We discovered that AUXIN RESPONSE FACTOR 2A (ARF2A), a recognized auxin signaling component, functions in the control of ripening. ARF2A expression is ripening regulated and reduced in the rin, nor and nr ripening mutants. It is also responsive to exogenous application of ethylene, auxin and abscisic acid (ABA). Over-expressing ARF2A in tomato resulted in blotchy ripening in which certain fruit regions turn red and possess accelerated ripening. ARF2A over-expressing fruit displayed early ethylene emission and ethylene signaling inhibition delayed their ripening phenotype, suggesting ethylene dependency. Both green and red fruit regions showed the induction of ethylene signaling components and master regulators of ripening. Comprehensive hormone profiling revealed that altered ARF2A expression in fruit significantly modified abscisates, cytokinins and salicylic acid while gibberellic acid and auxin metabolites were unaffected. Silencing of ARF2A further validated these observations as reducing ARF2A expression let to retarded fruit ripening, parthenocarpy and a disturbed hormonal profile. Finally, we show that ARF2A both homodimerizes and interacts with the ABA STRESS RIPENING (ASR1) protein, suggesting that ASR1 might be linking ABA and ethylene-dependent ripening. These results revealed that ARF2A interconnects signals of ethylene and additional hormones to co-ordinate the capacity of fruit tissue to initiate the complex ripening process. PMID:26959229

  7. Effects of oestrogen on microRNA expression in hormone-responsive breast cancer cells.

    PubMed

    Ferraro, Lorenzo; Ravo, Maria; Nassa, Giovanni; Tarallo, Roberta; De Filippo, Maria Rosaria; Giurato, Giorgio; Cirillo, Francesca; Stellato, Claudia; Silvestro, Silvana; Cantarella, Concita; Rizzo, Francesca; Cimino, Daniela; Friard, Olivier; Biglia, Nicoletta; De Bortoli, Michele; Cicatiello, Luigi; Nola, Ernesto; Weisz, Alessandro

    2012-06-01

    Oestrogen receptor alpha (ERα) is a ligand-dependent transcription factor that mediates oestrogen effects in hormone-responsive cells. Following oestrogenic activation, ERα directly regulates the transcription of target genes via DNA binding. MicroRNAs (miRNAs) represent a class of small noncoding RNAs that function as negative regulators of protein-coding gene expression. They are found aberrantly expressed or mutated in cancer, suggesting their crucial role as either oncogenes or tumour suppressor genes. Here, we analysed changes in miRNA expression in response to oestrogen in hormone-responsive breast cancer MCF-7 and ZR-75.1 cells by microarray-mediated expression profiling. This led to the identification of 172 miRNAs up- or down-regulated by ERα in response to 17β-oestradiol, of which 52 are similarly regulated by the hormone in the two cell models investigated. To identify mechanisms by which ERα exerts its effects on oestrogen-responsive miRNA genes, the oestrogen-dependent miRNA expression profiles were integrated with global in vivo ERα binding site mapping in the genome by ChIP-Seq. In addition, data from miRNA and messenger RNA (mRNA) expression profiles obtained under identical experimental conditions were compared to identify relevant miRNA target transcripts. Results show that miRNAs modulated by ERα represent a novel genomic pathway to impact oestrogen-dependent processes that affect hormone-responsive breast cancer cell behaviour. MiRNome analysis in tumour tissues from breast cancer patients confirmed a strong association between expression of these small RNAs and clinical outcome of the disease, although this appears to involve only marginally the oestrogen-regulated miRNAs identified in this study. PMID:22274890

  8. Sex hormones modulate the immune response to Plasmodium berghei ANKA in CBA/Ca mice.

    PubMed

    Legorreta-Herrera, Martha; Mosqueda-Romo, Néstor Aarón; Nava-Castro, Karen Elizabeth; Morales-Rodríguez, Ana Laura; Buendía-González, Fidel Orlando; Morales-Montor, Jorge

    2015-07-01

    Susceptibility to malaria differs between females and males, and this sexual dimorphism may have important implications for the effects of vaccines and drugs. However, little is known about the mechanisms mediating these sexual differences. Because the main differences between sexes are dictated by sex hormones, we studied the effect of gonadal steroids on immune responses to malaria in CBA/Ca mice. We decreased sex hormones levels by gonadectomy and evaluated the splenic index and the cells involved in the immune response, including T cells (CD3(+), CD4(+), CD8(+) and NK(+)), B cells and macrophages (Mac-3(+)) in the spleens of female and male mice infected with Plasmodium berghei ANKA. In addition, we measured antibody and cytokine levels in blood. Gonadectomy increased T(+) and B(+) splenic cells in both sexes but increased Mac-3(+) cells only in male mice. By contrast, gonadectomy decreased the NK(+) cell population only in male mice. In general, female mice developed higher antibody levels than males. Contrary to our expectations, gonadectomy increased the synthesis of IgG1, IgG2b, IgG3, and total IgG in female mice, indicating negative regulation of antibody production by female sex hormones. Gonadectomy increased the synthesis of tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) only in female mice, suggesting that female sex hormones have anti-inflammatory properties. This work demonstrates that the levels of sex hormones affect the immune response and should be considered when designing malaria vaccines. PMID:25876048

  9. Protein phosphatases in pancreatic islets

    PubMed Central

    Ortsäter, Henrik; Grankvist, Nina; Honkanen, Richard E.; Sjöholm1, Åke

    2014-01-01

    The prevalence of diabetes is increasing rapidly world-wide. A cardinal feature of most forms of diabetes is the lack of insulin-producing capability, due to the loss of insulin-producing β-cells, impaired glucose-sensitive insulin secretion from the β-cell, or a combination thereof, the reasons for which largely remain elusive. Reversible phosphorylation is an important and versatile mechanism for regulating the biological activity of many intracellular proteins, which, in turn, controls a variety of cellular functions. For instance, significant changes in protein kinase activities and in protein phosphorylation patterns occur subsequent to stimulation of insulin release by glucose. Therefore, the molecular mechanisms regulating phosphorylation of proteins involved in the insulin secretory process by the β-cell have been extensively investigated. However, far less is known about the role and regulation of protein dephosphorylation by various protein phosphatases. Herein we review extant data implicating serine/threonine and tyrosine phosphatases in various aspects of healthy and diabetic islet biology, ranging from control of hormonal stimulus-secretion coupling to mitogenesis and apoptosis. PMID:24681827

  10. Ethylene Response Factors: A Key Regulatory Hub in Hormone and Stress Signaling.

    PubMed

    Müller, Maren; Munné-Bosch, Sergi

    2015-09-01

    Ethylene is essential for many developmental processes and a key mediator of biotic and abiotic stress responses in plants. The ethylene signaling and response pathway includes Ethylene Response Factors (ERFs), which belong to the transcription factor family APETALA2/ERF. It is well known that ERFs regulate molecular response to pathogen attack by binding to sequences containing AGCCGCC motifs (the GCC box), a cis-acting element. However, recent studies suggest that several ERFs also bind to dehydration-responsive elements and act as a key regulatory hub in plant responses to abiotic stresses. Here, we review some of the recent advances in our understanding of the ethylene signaling and response pathway, with emphasis on ERFs and their role in hormone cross talk and redox signaling under abiotic stresses. We conclude that ERFs act as a key regulatory hub, integrating ethylene, abscisic acid, jasmonate, and redox signaling in the plant response to a number of abiotic stresses. PMID:26103991

  11. Update on Islet Transplantation

    PubMed Central

    McCall, Michael; James Shapiro, A.M.

    2012-01-01

    Clinical islet transplantation has progressed considerably over the past 12 years, and >750 patients with type 1 diabetes have received islet transplants internationally over this time. Many countries are beginning to accept the transition from research to accepted and funded clinical care, especially for patients with brittle control that cannot be stabilized by more conventional means. Major challenges remain, including the need for more than one donor, and the requirement for potent, chronic immunosuppression. Combining immunological tolerance both to allo- and autoantigens, and a limitless expandable source of stem cell- or xenograft-derived insulin-secreting cells represent remaining hurdles in moving this effective treatment to a potential cure for all those with type 1 or 2 diabetes. PMID:22762022

  12. Current status of islet xenotransplantation.

    PubMed

    Park, Chung-Gyu; Bottino, Rita; Hawthorne, Wayne J

    2015-11-01

    Cell therapy for Type 1 diabetes (T1D) utilizing islet cell transplantation can successfully restore endogenous insulin production in affected patients. Islet cell engraftment and survival are conditional on the use of efficacious anti-rejection therapies and on the availability of healthy donor cells. The scarcity of healthy human donor pancreata is a limiting factor in providing sufficient tissue to meet the demand for islet transplantation worldwide. A potential alternative to the use of cadaveric human donor pancreases is the use of animal sourced islets. Pancreatic islets obtained from pigs have emerged as an alternative to human tissues due to their great availability, physiological similarities to human islets, including the time-tested use of porcine insulin in diabetic patients and the ability to genetically modify the donor source. The evolution of refined, efficacious immunosuppressive therapies with reduced toxicity, improvements in donor management and genetic manipulation of the donor have all contributed to facilitate long-term function in pre-clinical models of pig islet grafts in non-human primates. As clinical consideration for this option is growing, and trials involving the use of porcine islets have begun, more compelling experimental data suggest that the use of pig islets may soon become a viable, safe, effective and readily available treatment for insulin deficiency in T1D patients. PMID:26253846

  13. A Reevaluation of the Role of the Unfolded Protein Response in Islet Dysfunction: Maladaptation or a Failure to Adapt?

    PubMed

    Herbert, Terence P; Laybutt, D Ross

    2016-06-01

    Endoplasmic reticulum (ER) stress caused by perturbations in ER homeostasis activates an adaptive response termed the unfolded protein response (UPR) whose function is to resolve ER stress. If unsuccessful, the UPR initiates a proapoptotic program to eliminate the malfunctioning cells from the organism. It is the activation of this proapoptotic UPR in pancreatic β-cells that has been implicated in the onset of type 2 diabetes and thus, in this context, is considered a maladaptive response. However, there is growing evidence that β-cell death in type 2 diabetes may not be caused by a maladaptive UPR but by the inhibition of the adaptive UPR. In this review, we discuss the evidence for a role of the UPR in β-cell dysfunction and death in the development of type 2 diabetes and ask the following question: Is β-cell dysfunction the result of a maladaptive UPR or a failure of the UPR to adequately adapt? The answer to this question is critically important in defining potential therapeutic strategies for the treatment and prevention of type 2 diabetes. In addition, we discuss the potential role of the adaptive UPR in staving off type 2 diabetes by enhancing β-cell mass and function in response to insulin resistance. PMID:27222391

  14. Quantitative Electron Microscopic Autoradiography of Insulin, Glucagon, and Somatostatin Binding Sites on Islets

    NASA Astrophysics Data System (ADS)

    Patel, Yogesh C.; Amherdt, Mylene; Orci, Lelio

    1982-09-01

    After monolayer cultures of rat islets were exposed to [125I]insulin, [125I]glucagon, and [125I]tyrosinyl somatostatin, specific autoradiographic grains associated with each radioactively labeled ligand were found on B, A, and D cells. The density of labeling of the B, A, and D cells with each labeled ligand correlated well with the known actions of the three hormones on each of the islet cells.

  15. Ontogeny of Neuro-Insular Complexes and Islets Innervation in the Human Pancreas

    PubMed Central

    Proshchina, Alexandra E.; Krivova, Yulia S.; Barabanov, Valeriy M.; Saveliev, Sergey V.

    2014-01-01

    The ontogeny of the neuro-insular complexes (NIC) and the islets innervation in human pancreas has not been studied in detail. Our aim was to describe the developmental dynamics and distribution of the nervous system structures in the endocrine part of human pancreas. We used double-staining with antibodies specific to pan-neural markers [neuron-specific enolase (NSE) and S100 protein] and to hormones of pancreatic endocrine cells. NSE and S100-positive nerves and ganglia were identified in the human fetal pancreas from gestation week (gw) 10 onward. Later the density of S100 and NSE-positive fibers increased. In adults, this network was sparse. The islets innervation started to form from gw 14. NSE-containing endocrine cells were identified from gw 12 onward. Additionally, S100-positive cells were detected both in the periphery and within some of the islets starting at gw 14. The analysis of islets innervation has shown that the fetal pancreas contained NIC and the number of these complexes was reduced in adults. The highest density of NIC is detected during middle and late fetal periods, when the mosaic islets, typical for adults, form. The close integration between the developing pancreatic islets and the nervous system structures may play an important role not only in the hormone secretion, but also in the islets morphogenesis. PMID:24795697

  16. Functional imaging of glucose-evoked rat islet activities using transient intrinsic optical signals

    NASA Astrophysics Data System (ADS)

    Yao, Xin-Cheng; Cui, Wan-Xing; Li, Yi-Chao; Zhang, Wei; Lu, Rong-Wen; Thompson, Anthony; Amthor, Franklin; Wang, Xu-Jing

    2012-05-01

    We demonstrate intrinsic optical signal (IOS) imaging of intact rat islet, which consists of many endocrine cells working together. A near-infrared digital microscope was employed for optical monitoring of islet activities evoked by glucose stimulation. Dynamic NIR images revealed transient IOS responses in the islet activated by low-dose (2.75 mM) and high-dose (5.5 mM) glucose stimuli. Comparative experiments and quantitative analysis indicated that both glucose metabolism and calcium/insulin dynamics might contribute to the observed IOS responses. Further investigation of the IOS imaging technology may provide a high resolution method for ex vivo functional examination of the islet, which is important for advanced study of diabetes associated islet dysfunctions and for improved quality control of donor islets for transplantation.

  17. No hormone to rule them all: Interactions of plant hormones during the responses of plants to pathogens.

    PubMed

    Shigenaga, Alexandra M; Argueso, Cristiana T

    2016-08-01

    Plant hormones are essential regulators of plant growth and immunity. In the last few decades, a vast amount of information has been obtained detailing the role of different plant hormones in immunity, and how they work together to ultimately shape the outcomes of plant pathogen interactions. Here we provide an overview on the roles of the main classes of plant hormones in the regulation of plant immunity, highlighting their metabolic and signaling pathways and how plants and pathogens utilize these pathways to activate or suppress defence. PMID:27312082

  18. Improving Response to Hormone Therapy in Breast Cancer: New Targets, New Therapeutic Options.

    PubMed

    Rugo, Hope S; Vidula, Neelima; Ma, Cynthia

    2016-01-01

    The majority of breast cancer expresses the estrogen and or progesterone receptors (ER and PR). In tumors without concomitant HER2 amplification, hormone therapy is a major treatment option for all disease stages. Resistance to hormonal therapy is associated with disease recurrence and progression. Recent studies have identified a number of resistance mechanisms leading to estrogen-independent growth of hormone receptor-positive (HR+) breast cancer as a result of genetic and epigenetic alterations, which could be exploited as novel therapeutic targets. These include acquired mutations in ER-alpha (ESR1) in response to endocrine deprivation; constitutive activation of cyclin-dependent kinases (CDK) 4 and 6; cross talk between ER and growth factor receptor signaling such as HER family members, fibroblast growth factor receptor (FGFR) pathways, intracellular growth, and survival signals PI3K/Akt/mTOR; and epigenetic modifications by histone deacetylase (HDAC) as well as interactions with tumor microenvironment and host immune response. Inhibitors of these pathways are being developed to improve efficacy of hormonal therapy for treatment of both metastatic and early-stage disease. Two agents are currently approved in the United States for the treatment of metastatic HR+ breast cancer, including the mTOR inhibitor everolimus and the CDK4/6 inhibitor palbociclib. Management of toxicity is a critical aspect of treatment; the primary toxicity of everolimus is stomatitis (treated with topical steroids) and of palbociclib is neutropenia (treated with dose reduction/delay). Many agents are in clinical trials, primarily in combination with hormone therapy; novel combinations are under active investigation. PMID:27249746

  19. Constitutional delay influences the auxological response to growth hormone treatment in children with short stature and growth hormone sufficiency.

    PubMed

    Gunn, Katherine C; Cutfield, Wayne S; Hofman, Paul L; Jefferies, Craig A; Albert, Benjamin B; Gunn, Alistair J

    2014-01-01

    In a retrospective, population based cohort study, we examined whether constitutional delay was associated with the growth response to growth hormone (GH) in children with short stature and normal GH responses. 70 patients were treated with 21 GH iu/m2/week from 1975 to 2013 throughout New Zealand. Demographic and auxological data were prospectively collected and standard deviation scores (SDS) were calculated for height (HtSDS), yearly growth velocity (GV-SDS), body mass index (BMI-SDS) and predicted adult height (PAH-SDS) at time of the last available bone age. In the first year, GH was associated with marked increase in HtSDS (+0.46 (0.19, 0.76), p < 0.001) and GV-SDS (from -1.9 (-3.6, -0.7) to +2.7 (0.45, 4.2), p < 0.001). The increase in HtSDS but not in GV-SDS was greatest with younger patients and greater bone age delay, with no effect of sex, BMI-SDS or baseline HtSDS. PAH-SDS increased with treatment (+0.94 (0.18, 1.5)); increased PAH-SDS was associated with less bone age delay and greater initial increase in HtSDS. This study shows that greater bone age delay was associated with greater initial improvement in height but less improvement in predicted adult heights, suggesting that children with very delayed bone ages may show accelerated maturation during GH treatment. PMID:25317732

  20. Retention of gene expression in porcine islets after agarose encapsulation and long-term culture.

    PubMed

    Dumpala, Pradeep R; Holdcraft, Robert W; Martis, Prithy C; Laramore, Melissa A; Parker, Thomas S; Levine, Daniel M; Smith, Barry H; Gazda, Lawrence S

    2016-08-01

    Agarose encapsulation of porcine islets allows extended in vitro culture, providing ample time to determine the functional capacity of the islets and conduct comprehensive microbiological safety testing prior to implantation as a treatment for type 1 diabetes mellitus. However, the effect that agarose encapsulation and long-term culture may have on porcine islet gene expression is unknown. The aim of the present study was to compare the transcriptome of encapsulated porcine islets following long-term in vitro culture against free islets cultured overnight. Global gene expression analysis revealed no significant change in the expression of 98.47% of genes. This indicates that the gene expression profile of free islets is highly conserved following encapsulation and long-term culture. Importantly, the expression levels of genes that code for critical hormones secreted by islets (insulin, glucagon, and somatostatin) as well as transcripts encoding proteins involved in their packaging and secretion are unchanged. While a small number of genes known to play roles in the insulin secretion and insulin signaling pathways are differentially expressed, our results show that overall gene expression is retained following islet isolation, agarose encapsulation, and long-term culture. PMID:27261433

  1. Characterization of the Human Pancreatic Islet Proteome by Two-Dimensional LC/MS/MS

    SciTech Connect

    Metz, Thomas O.; Jacobs, Jon M.; Gritsenko, Marina A.; Fontes, Ghislaine; Qian, Weijun; Camp, David G.; Poitout, Vincent J.; Smith, Richard D.

    2006-12-01

    Research to elucidate the pathogenesis of type 1 diabetes mellitus has traditionally focused on the genetic and immunological factors associated with the disease, and, until recently, has not considered the target cell. While there have been reports detailing proteomic analyses of established islet cell lines or isolated rodent islets, the information gained is not always easily extrapolated to humans. Therefore, extensive characterization of the human islet proteome could result in better understanding of islet biology and lead to more effective treatment strategies. We have applied a two-dimensional LC-MS/MS-based analysis to the characterization of the human islet proteome, resulting in the detection of 29,021 unique peptides corresponding to 4,925 proteins. As expected, major islet hormones (insulin, glucagon, somatostatin), beta-cell enriched secretory products (IAPP), ion channels (K-ATP channel), and transcription factors (PDX-1, Nkx 6.1, HNF-1 beta) were detected. In addition, significant proteome coverage of metabolic enzymes and cellular pathways was obtained, including the insulin signaling cascade and the MAP kinase, NF-κβ, and JAK/STAT pathways. This work represents the most extensive characterization of the human islet proteome to date and provides a peptide reference library that may be utilized in future studies of islet biology and type 1 diabetes.

  2. Neurotransmitters and Neuropeptides: New Players in the Control of Islet of Langerhans' Cell Mass and Function.

    PubMed

    Di Cairano, Eliana S; Moretti, Stefania; Marciani, Paola; Sacchi, Vellea Franca; Castagna, Michela; Davalli, Alberto; Folli, Franco; Perego, Carla

    2016-04-01

    Islets of Langerhans control whole body glucose homeostasis, as they respond, releasing hormones, to changes in nutrient concentrations in the blood stream. The regulation of hormone secretion has been the focus of attention for a long time because it is related to many metabolic disorders, including diabetes mellitus. Endocrine cells of the islet use a sophisticate system of endocrine, paracrine and autocrine signals to synchronize their activities. These signals provide a fast and accurate control not only for hormone release but also for cell differentiation and survival, key aspects in islet physiology and pathology. Among the different categories of paracrine/autocrine signals, this review highlights the role of neurotransmitters and neuropeptides. In a manner similar to neurons, endocrine cells synthesize, accumulate, release neurotransmitters in the islet milieu, and possess receptors able to decode these signals. In this review, we provide a comprehensive description of neurotransmitter/neuropetide signaling pathways present within the islet. Then, we focus on evidence supporting the concept that neurotransmitters/neuropeptides and their receptors are interesting new targets to preserve β-cell function and mass. A greater understanding of how this network of signals works in physiological and pathological conditions would advance our knowledge of islet biology and physiology and uncover potentially new areas of pharmacological intervention. J. Cell. Physiol. 231: 756-767, 2016. © 2015 Wiley Periodicals, Inc. PMID:26332080

  3. Sex differences in acute hormonal and subjective response to naltrexone: the impact of menstrual cycle phase

    PubMed Central

    Roche, Daniel J.O.; King, Andrea C.

    2015-01-01

    Women often exhibit larger hormonal and subjective responses to opioid receptor antagonists than men, but the biological mechanisms mediating this effect remain unclear. Among women, fluctuations in estradiol (E2) and progesterone (P4) across the menstrual cycle (MC) affect the endogenous opioid system. Therefore, the goal of the current study was to compare acute naltrexone response between women in the early follicular phase of the MC (low E2 and P4), women in the luteal phase of the MC (high E2 and P4), and men. Seventy healthy controls (n = 46 women) participated in two morning sessions in which they received 50 mg naltrexone or placebo in a randomized, counterbalanced order. Women were randomized to complete both sessions in either the early follicular (n = 23) or luteal phase of the MC. Serum cortisol, prolactin, and luteinizing hormone (LH), salivary cortisol, and subjective response were assessed upon arrival to the laboratory and at regular intervals after pill administration. In luteal and early follicular women but not men, naltrexone (vs. placebo) increased serum cortisol and prolactin levels from baseline; however, the naltrexone-induced increases in these hormones were significantly greater in luteal women than early follicular women. Additionally, only luteal women demonstrated an increase from baseline in salivary cortisol levels and the severity of adverse drug effects in response to naltrexone. In sum, the results indicate that luteal phase women are more sensitive to acute hormonal and subjective effects of naltrexone than early follicular women and men. These findings may have important implications for the use of naltrexone in women. PMID:25459893

  4. Sex differences in acute hormonal and subjective response to naltrexone: The impact of menstrual cycle phase.

    PubMed

    Roche, Daniel J O; King, Andrea C

    2015-02-01

    Women often exhibit larger hormonal and subjective responses to opioid receptor antagonists than men, but the biological mechanisms mediating this effect remain unclear. Among women, fluctuations in estradiol (E2) and progesterone (P4) across the menstrual cycle (MC) affect the endogenous opioid system. Therefore, the goal of the current study was to compare acute naltrexone response between women in the early follicular phase of the MC (low E2 and P4), women in the luteal phase of the MC (high E2 and P4), and men. Seventy healthy controls (n=46 women) participated in two morning sessions in which they received 50mg naltrexone or placebo in a randomized, counterbalanced order. Women were randomized to complete both sessions in either the early follicular (n=23) or luteal phase of the MC. Serum cortisol, salivary cortisol, prolactin, luteinizing hormone (LH), and subjective response were assessed upon arrival to the laboratory and at regular intervals after pill administration. In luteal and early follicular women but not men, naltrexone (vs. placebo) increased serum cortisol and prolactin levels from baseline; however, the naltrexone-induced increases in these hormones were significantly greater in luteal women than early follicular women. Additionally, only luteal women demonstrated an increase from baseline in salivary cortisol levels and the severity of adverse drug effects in response to naltrexone. In sum, the results indicate that luteal phase women are more sensitive to acute hormonal and subjective effects of naltrexone than early follicular women and men. These findings may have important implications for the use of naltrexone in women. PMID:25459893

  5. Intra- and Inter-Islet Synchronization of Metabolically Driven Insulin Secretion

    PubMed Central

    Pedersen, Morten Gram; Bertram, Richard; Sherman, Arthur

    2005-01-01

    Insulin secretion from pancreatic β-cells is pulsatile with a period of 5–10 min and is believed to be responsible for plasma insulin oscillations with similar frequency. To observe an overall oscillatory insulin profile it is necessary that the insulin secretion from individual β-cells is synchronized within islets, and that the population of islets is also synchronized. We have recently developed a model in which pulsatile insulin secretion is produced as a result of calcium-driven electrical oscillations in combination with oscillations in glycolysis. We use this model to investigate possible mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model “liver,” which responds to the level of insulin secretion by adjusting the blood glucose concentration in an appropriate way. Since all islets are exposed to the blood, the distributed islet-liver system can synchronize the individual islet insulin oscillations. Thus, we demonstrate how intra-islet and inter-islet synchronization of insulin oscillations may be achieved. PMID:15834002

  6. Device design and materials optimization of conformal coating for islets of Langerhans

    PubMed Central

    Tomei, Alice A.; Manzoli, Vita; Fraker, Christopher A.; Giraldo, Jaime; Velluto, Diana; Najjar, Mejdi; Pileggi, Antonello; Molano, R. Damaris; Ricordi, Camillo; Stabler, Cherie L.; Hubbell, Jeffrey A.

    2014-01-01

    Encapsulation of islets of Langerhans may represent a way to transplant islets in the absence of immunosuppression. Traditional methods for encapsulation lead to diffusional limitations imposed by the size of the capsules (600–1,000 μm in diameter), which results in core hypoxia and delayed insulin secretion in response to glucose. Moreover, the large volume of encapsulated cells does not allow implantation in sites that might be more favorable to islet cell engraftment. To address these issues, we have developed an encapsulation method that allows conformal coating of islets through microfluidics and minimizes capsule size and graft volume. In this method, capsule thickness, rather than capsule diameter, is constant and tightly defined by the microdevice geometry and the rheological properties of the immiscible fluids used for encapsulation within the microfluidic system. We have optimized the method both computationally and experimentally, and found that conformal coating allows for complete encapsulation of islets with a thin (a few tens of micrometers) continuous layer of hydrogel. Both in vitro and in vivo in syngeneic murine models of islet transplantation, the function of conformally coated islets was not compromised by encapsulation and was comparable to that of unencapsulated islets. We have further demonstrated that the structural support conferred by the coating materials protected islets from the loss of function experienced by uncoated islets during ex vivo culture. PMID:24982192

  7. Thyroid hormones inhibit TGF-β signaling and attenuate fibrotic responses.

    PubMed

    Alonso-Merino, Elvira; Martín Orozco, Rosa; Ruíz-Llorente, Lidia; Martínez-Iglesias, Olaia A; Velasco-Martín, Juan Pedro; Montero-Pedrazuela, Ana; Fanjul-Rodríguez, Luisa; Contreras-Jurado, Constanza; Regadera, Javier; Aranda, Ana

    2016-06-14

    TGF-β, the most potent profibrogenic factor, acts by activating SMAD (mothers against decapentaplegic) transcription factors, which bind to SMAD-binding elements in target genes. Here, we show that the thyroid hormone triiodothyronine (T3), through binding to its nuclear receptors (TRs), is able to antagonize transcriptional activation by TGF-β/SMAD. This antagonism involves reduced phosphorylation of SMADs and a direct interaction of the receptors with SMAD3 and SMAD4 that is independent of T3-mediated transcriptional activity but requires residues in the receptor DNA binding domain. T3 reduces occupancy of SMAD-binding elements in response to TGF-β, reducing histone acetylation and inhibiting transcription. In agreement with this transcriptional cross-talk, T3 is able to antagonize fibrotic processes in vivo. Liver fibrosis induced by carbon tetrachloride is attenuated by thyroid hormone administration to mice, whereas aged TR knockout mice spontaneously accumulate collagen. Furthermore, skin fibrosis induced by bleomycin administration is also reduced by the thyroid hormones. These findings define an important function of the thyroid hormone receptors and suggest TR ligands could have beneficial effects to block the progression of fibrotic diseases. PMID:27247403

  8. Hormonal Regulation of Response to Oxidative Stress in Insects—An Update

    PubMed Central

    Kodrík, Dalibor; Bednářová, Andrea; Zemanová, Milada; Krishnan, Natraj

    2015-01-01

    Insects, like other organisms, must deal with a wide variety of potentially challenging environmental factors during the course of their life. An important example of such a challenge is the phenomenon of oxidative stress. This review summarizes the current knowledge on the role of adipokinetic hormones (AKH) as principal stress responsive hormones in insects involved in activation of anti-oxidative stress response pathways. Emphasis is placed on an analysis of oxidative stress experimentally induced by various stressors and monitored by suitable biomarkers, and on detailed characterization of AKH’s role in the anti-stress reactions. These reactions are characterized by a significant increase of AKH levels in the insect body, and by effective reversal of the markers—disturbed by the stressors—after co-application of the stressor with AKH. A plausible mechanism of AKH action in the anti-oxidative stress response is discussed as well: this probably involves simultaneous employment of both protein kinase C and cyclic adenosine 3′,5′-monophosphate pathways in the presence of extra and intra-cellular Ca2+ stores, with the possible involvement of the FoxO transcription factors. The role of other insect hormones in the anti-oxidative defense reactions is also discussed. PMID:26516847

  9. Hormonal Regulation of Response to Oxidative Stress in Insects-An Update.

    PubMed

    Kodrík, Dalibor; Bednářová, Andrea; Zemanová, Milada; Krishnan, Natraj

    2015-01-01

    Insects, like other organisms, must deal with a wide variety of potentially challenging environmental factors during the course of their life. An important example of such a challenge is the phenomenon of oxidative stress. This review summarizes the current knowledge on the role of adipokinetic hormones (AKH) as principal stress responsive hormones in insects involved in activation of anti-oxidative stress response pathways. Emphasis is placed on an analysis of oxidative stress experimentally induced by various stressors and monitored by suitable biomarkers, and on detailed characterization of AKH's role in the anti-stress reactions. These reactions are characterized by a significant increase of AKH levels in the insect body, and by effective reversal of the markers-disturbed by the stressors-after co-application of the stressor with AKH. A plausible mechanism of AKH action in the anti-oxidative stress response is discussed as well: this probably involves simultaneous employment of both protein kinase C and cyclic adenosine 3',5'-monophosphate pathways in the presence of extra and intra-cellular Ca(2+) stores, with the possible involvement of the FoxO transcription factors. The role of other insect hormones in the anti-oxidative defense reactions is also discussed. PMID:26516847

  10. Microarray Analysis of Rat Pancreas Reveals Altered Expression of Alox15 and Regenerating Islet-Derived Genes in Response to Iron Deficiency and Overload

    PubMed Central

    Coffey, Richard; Nam, Hyeyoung; Knutson, Mitchell D.

    2014-01-01

    It is well known that iron overload can result in pancreatic iron deposition, beta-cell destruction, and diabetes in humans. Recent studies in animals have extended the link between iron status and pancreatic function by showing that iron depletion confers protection against beta-cell dysfunction and diabetes. The aim of the present study was to identify genes in the pancreas that are differentially expressed in response to iron deficiency or overload. Weanling male Sprague-Dawley rats (n = 6/group) were fed iron-deficient, iron-adequate, or iron-overloaded diets for 3 weeks to alter their iron status. Total RNA was isolated from the pancreases and pooled within each group for microarray analyses in which gene expression levels were compared to those in iron-adequate controls. In iron-deficient pancreas, a total of 66 genes were found to be differentially regulated (10 up, 56 down), whereas in iron-overloaded pancreas, 164 genes were affected (82 up, 82 down). The most up-regulated transcript in iron-deficient pancreas was arachidonate 15-lipoxygenase (Alox15), which has been implicated in the development of diabetes. In iron-overloaded pancreas, the most upregulated transcripts were Reg1a, Reg3a, and Reg3b belonging to the regenerating islet-derived gene (Reg) family. Reg expression has been observed in response to pancreatic stress and is thought to facilitate pancreatic regeneration. Subsequent qRT-PCR validation indicated that Alox15 mRNA levels were 4 times higher in iron-deficient than in iron-adequate pancreas and that Reg1a, Reg3a, and Reg3b mRNA levels were 17–36 times higher in iron-overloaded pancreas. The elevated Alox15 mRNA levels in iron-deficient pancreas were associated with 8-fold higher levels of Alox15 protein as indicated by Western blotting. Overall, these data raise the possibility that Reg expression may serve as a biomarker for iron-related pancreatic stress, and that iron deficiency may adversely affect the risk of developing

  11. Low gravity rotational culture and the integration of immunomodulatory stem cells reduce human islet allo-reactivity.

    PubMed

    Qureshi, Khalid M; Lee, Jou; Paget, Michelle B; Bailey, Clifford J; Curnow, S John; Murray, Hilary E; Downing, Richard

    2015-01-01

    Modification of human islets prior to transplantation may improve long-term clinical outcome in terms of diabetes management, by supporting graft function and reducing the potential for allo-rejection. Intragraft incorporation of stem cells secreting beta (β)-cell trophic and immunomodulatory factors represents a credible approach, but requires suitable culture methods to facilitate islet alteration without compromising integrity. This study employed a three-dimensional rotational cell culture system (RCCS) to achieve modification, preserve function, and ultimately influence immune cell responsiveness to human islets. Islets underwent intentional dispersal and rotational culture-assisted aggregation with amniotic epithelial cells (AEC) exhibiting intrinsic immunomodulatory potential. Reassembled islet constructs were assessed for functional integrity, and their ability to induce an allo-response in discrete T-cell subsets determined using mixed islet:lymphocyte reaction assays. RCCS supported the formation of islet:AEC aggregates with improved insulin secretory capacity compared to unmodified islets. Further, the allo-response of peripheral blood mononuclear cell (PBMC) and purified CD4+ and CD8+ T-cell subsets to AEC-bearing grafts was significantly (p < 0.05) attenuated. Rotational culture enables pre-transplant islet modification involving their integration with immunomodulatory stem cells capable of subduing the allo-reactivity of T cells relevant to islet rejection. The approach may play a role in achieving acute and long-term graft survival in islet transplantation. PMID:25382449

  12. Overlapping dose responses of spermatogenic and extragonadal testosterone actions jeopardize the principle of hormonal male contraception

    PubMed Central

    Oduwole, Olayiwola O.; Vydra, Natalia; Wood, Nicholas E. M.; Samanta, Luna; Owen, Laura; Keevil, Brian; Donaldson, Mandy; Naresh, Kikkeri; Huhtaniemi, Ilpo T.

    2014-01-01

    Testosterone (T), alone or in combination with progestin, provides a promising approach to hormonal male contraception. Its principle relies on enhanced negative feedback of exogenous T to suppress gonadotropins, thereby blocking the testicular T production needed for spermatogenesis, while simultaneously maintaining the extragonadal androgen actions, such as potency and libido, to avoid hypogonadism. A serious drawback of the treatment is that a significant proportion of men do not reach azoospermia or severe oligozoospermia, commensurate with contraceptive efficacy. We tested here, using hypogonadal luteinizing hormone/choriongonadotropin receptor (LHCGR) knockout (LHR−/−) mice, the basic principle of the T-based male contraceptive method, that a specific T dose could maintain extragonadal androgen actions without simultaneously activating spermatogenesis. LHR−/− mice were treated with increasing T doses, and the responses of their spermatogenesis and extragonadal androgen actions (including gonadotropin suppression and sexual behavior) were assessed. Conspicuously, all dose responses to T were practically superimposable, and no dose of T could be defined that would maintain sexual function and suppress gonadotropins without simultaneously activating spermatogenesis. This finding, never addressed in clinical contraceptive trials, is not unexpected in light of the same androgen receptor mediating androgen actions in all organs. When extrapolated to humans, our findings may jeopardize the current approach to hormonal male contraception and call for more effective means of inhibiting intratesticular T production or action, to achieve consistent spermatogenic suppression.—Oduwole, O. O., Vydra, N., Wood, N. E. M., Samanta, L., Owen, L., Keevil, B., Donaldson, M., Naresh, K., Huhtaniemi, I. T. Overlapping dose responses of spermatogenic and extragonadal testosterone actions jeopardize the principle of hormonal male contraception. PMID:24599970

  13. Metabolomics Analysis of Hormone-Responsive and Triple-Negative Breast Cancer Cell Responses to Paclitaxel Identify Key Metabolic Differences.

    PubMed

    Stewart, Delisha A; Winnike, Jason H; McRitchie, Susan L; Clark, Robert F; Pathmasiri, Wimal W; Sumner, Susan J

    2016-09-01

    To date, no targeted therapies are available to treat triple negative breast cancer (TNBC), while other breast cancer subtypes are responsive to current therapeutic treatment. Metabolomics was conducted to reveal differences in two hormone receptor-negative TNBC cell lines and two hormone receptor-positive Luminal A cell lines. Studies were conducted in the presence and absence of paclitaxel (Taxol). TNBC cell lines had higher levels of amino acids, branched-chain amino acids, nucleotides, and nucleotide sugars and lower levels of proliferation-related metabolites like choline compared with Luminal A cell lines. In the presence of paclitaxel, each cell line showed unique metabolic responses, with some similarities by type. For example, in the Luminal A cell lines, levels of lactate and creatine decreased while certain choline metabolites and myo-inositol increased with paclitaxel. In the TNBC cell lines levels of glutamine, glutamate, and glutathione increased, whereas lysine, proline, and valine decreased in the presence of drug. Profiling secreted inflammatory cytokines in the conditioned media demonstrated a greater response to paclitaxel in the hormone-positive Luminal cells compared with a secretion profile that suggested greater drug resistance in the TNBC cells. The most significant differences distinguishing the cell types based on pathway enrichment analyses were related to amino acid, lipid and carbohydrate metabolism pathways, whereas several biological pathways were differentiated between the cell lines following treatment. PMID:27447733

  14. Introduction of exogenous growth hormone receptors augments growth hormone-responsive insulin biosynthesis in rat insulinoma cells

    SciTech Connect

    Billestrup, N.; Moeldrup, A.; Serup, P.; Nielsen, J.H. ); Mathews, L.S.; Norstedt, G. )

    1990-09-01

    The stimulation of insulin biosynthesis in the pancreatic insulinoma cell line RIN5-AH by growth hormone (GH) is initiated by GH binding to specific receptors. To determine whether the recently cloned rat hepatic GH receptor is able to mediate the insulinotropic effect of GH, the authors have transfected a GH receptor cDNA under the transcriptional control of the human metallothionein promoter into RIN5-AH cells. The transfected cells were found to exhibit an increased expression of GH receptors and to contain a specific GH receptor mRNA that was not expressed in the parent cell line. The expression of GH receptors in one clone (1.24) selected for detailed analysis was increased 2.6-fold compared to untransfected cells. The increased GH receptor expression was accompanied by an increased responsiveness to GH. Thus, the maximal GH-stimulated increase of insulin biosynthesis was 4.1-fold in 1.24 cells compared to 1.9-fold in the nontransfected RIN5-AH cells. The expression of the transfected receptor was stimulated 1.6- and 2.3-fold when cells were cultured in the presence of 25 or 50 {mu}M Zn{sup 2+} was associated with an increased magnitude of GH-stimulated insulin biosynthesis. A close stoichiometric relationship between the level of receptor expression and the level of GH-stimulated insulin biosynthesis was observed. They conclude from these results that the hepatic GH receptor is able to mediate the effect of GH on insulin biosynthesis in RIN5-AH cells.

  15. Taste matters - effects of bypassing oral stimulation on hormone and appetite responses.

    PubMed

    Spetter, Maartje S; Mars, Monica; Viergever, Max A; de Graaf, Cees; Smeets, Paul A M

    2014-10-01

    The interaction between oral and gastric signals is an important part of food intake regulation. Previous studies suggest that bypassing oral stimulation diminishes the suppression of hunger and increases gastric emptying rate. However, the role of appetite hormones, like cholecystokinin-8 and ghrelin, in this process is still unclear. Our objective was to determine the contributions of gastric and oral stimulation to subsequent appetite and hormone responses and their effect on ad libitum intake. Fourteen healthy male subjects (age 24.6±3.8y, BMI 22.3±1.6kg/m(2)) completed a randomized, single-blinded, cross-over experiment with 3 treatment-sessions: 1) Stomach distention: naso-gastric infusion of 500mL/0kJ water, 2) Stomach distention with caloric content: naso-gastric infusion of 500mL/1770kJ chocolate milk, and 3) Stomach distention with caloric content and oral exposure: oral administration of 500mL/1770kJ chocolate milk. Changes in appetite ratings and plasma glucose, insulin, cholecystokinin-8, and active and total ghrelin concentrations were measured at fixed time-points up to 30min after infusion or oral administration. Subsequently, subjects consumed an ad libitum buffet meal. Oral administration reduced appetite ratings more than both naso-gastric infusions (P<0.0001). Gastric infusion of a caloric load increased insulin and cholecystokinin-8 and decreased total ghrelin concentrations more than ingestion (all P<0.0001). No differences in active ghrelin response were observed between conditions. Ad libitum intake did not differ between oral and gastric administration of chocolate milk (P>0.05). Thus, gastric infusion of nutrients induces greater appetite hormone responses than ingestion does. These data provide novel and additional evidence that bypassing oral stimulation not only affects the appetite profile but also increases anorexigenic hormone responses, probably driven in part by faster gastric emptying. This confirms the idea that learned

  16. Effect of dark pretreatment on the kinetics of response of barley pulvini to gravistimulation and hormones

    NASA Technical Reports Server (NTRS)

    Brock, T. G.; Kaufman, P. B.

    1988-01-01

    Starch in pulvinus amyloplasts of barley (Hordeum vulgare cv Larker) disappears when 45-day-old, light-grown plants are given 5 days of continuous darkness. The effect of this loss on the pulvinus graviresponse was evaluated by following changes in the kinetics of response during the 5-day dark period. Over 5 days of dark pretreatment, the lag to initial graviresponse and the subsequent half-time to maximum steady state bending rate increased significantly while the maximum bending rate did not change. The change in response to applied indoleacetic acid (100 micromolar) plus gibberellic acid (10 micromolar) without gravistimulation, under identical dark pretreatments, was used as a model system for the response component of gravitropism. Dark pretreatment did not change the lag to initial response following hormone application to vertical pulvini, but both the maximum bending rate and the half-time to the maximum rate were significantly reduced. Also, after dark pretreatment, significant bending responses following hormone application were observed in vertical segments with or without added sucrose, while gravistimulation produced a response only if segments were given sucrose. These results indicate that starch-filled amyloplasts are required for the graviresponse of barley pulvini and suggest that they function in the stimulus perception and signal transduction components of gravitropism.

  17. Reporter islets in the eye reveal the plasticity of the endocrine pancreas

    PubMed Central

    Ilegems, Erwin; Dicker, Andrea; Speier, Stephan; Sharma, Aarti; Bahow, Alan; Edlund, Patrick Karlsson; Leibiger, Ingo B.; Berggren, Per-Olof

    2013-01-01

    The islets of Langerhans constitute the endocrine part of the pancreas and are responsible for maintenance of blood glucose homeostasis. They are deeply embedded in the exocrine pancreas, limiting their accessibility for functional studies. Understanding regulation of function and survival and assessing the clinical outcomes of individual treatment strategies for diabetes requires a monitoring system that continuously reports on the endocrine pancreas. We describe the application of a natural body window that successfully reports on the properties of in situ pancreatic islets. As proof of principle, we transplanted “reporter islets” into the anterior chamber of the eye of leptin-deficient mice. These islets displayed obesity-induced growth and vascularization patterns that were reversed by leptin treatment. Hence, reporter islets serve as optically accessible indicators of islet function in the pancreas, and also reflect the efficacy of specific treatment regimens aimed at regulating islet plasticity in vivo. PMID:24248353

  18. Stimulation of hormone-responsive adenylate cyclase activity by a factor present in the cell cytosol.

    PubMed Central

    MacNeil, S; Crawford, A; Amirrasooli, H; Johnson, S; Pollock, A; Ollis, C; Tomlinson, S

    1980-01-01

    1. Homogenates of whole tissues were shown to contain both intracellular and extracellular factors that affected particulate adenylate cyclase activity in vitro. Factors present in the extracellular fluids produced an inhibition of basal, hormone- and fluoride-stimulated enzyme activity but factors present in the cell cytosol increased hormone-stimulated activity with relatively little effect on basal or fluoride-stimulated enzyme activity. 2. The existence of this cytosol factor or factors was investigated using freshly isolated human platelets, freshly isolated rat hepatocytes, and cultured cells derived from rat osteogenic sarcoma, rat calvaria, mouse melanoma, pig aortic endothelium, human articular cartilage chondrocytes and human bronchial carcinoma (BEN) cells. 3. The stimulation of the hormone response by the cytosol factor ranged from 60 to 890% depending on the tissue of origin of the adenylate cyclase. 4. In each case the behaviour of the factor was similar to the action of GTP on that particular adenylate cyclase preparation. 5. No evidence of tissue or species specificity was found, as cytosols stimulated adenylate cyclase from their own and unrelated tissues to the same degree. 6. In the human platelet, the inclusion of the cytosol in the assay of adenylate cyclase increased the rate of enzyme activity in response to stimulation by prostaglandin E1 without affecting the amount of prostaglandin E1 required for half-maximal stimulation or the characteristics of enzyme activation by prostaglandin E. PMID:7396869

  19. Receptors bound to antiprogestin from abortive complexes with hormone responsive elements.

    PubMed

    Guiochon-Mantel, A; Loosfelt, H; Ragot, T; Bailly, A; Atger, M; Misrahi, M; Perricaudet, M; Milgrom, E

    1988-12-15

    The mechanism of action of antisteroids is not understood and explanations of their antagonistic activity have been sought at all levels of hormone action. It has been proposed that antisteroids, after binding to receptor, trap it into a non-activated (non DNA-binding) form possibly through interaction with a heat-shock protein of relative molecular mass (Mr) 90,000 (90 K), or that the antisteroids provoke binding of receptor to nonspecific DNA sites but not to hormone responsive elements (HREs), or that the antisteroid-receptor complexes can bind to HREs but form abortive complexes that fail to regulate transcription. We have constructed a deleted cDNA encoding a mutant form of rabbit progesterone receptor which exhibits constitutive activity, that is, binds to HREs in the absence of hormone and thus bypasses the first two steps discussed above. Co-transfection experiments allowed the expression of both constitutive and wild-type receptors in the same recipient cells. Antiprogestin RU486-wild-type receptor complexes completely suppressed the activity of the constitutive receptor on a reporter gene, showing that the inhibition is at the level of their common responsive elements. PMID:3200320

  20. Prolonged activation of human islet cannabinoid receptors in vitro induces adaptation but not dysfunction

    PubMed Central

    Vilches-Flores, Alonso; Franklin, Zara; Hauge-Evans, Astrid C.; Liu, Bo; Huang, Guo C.; Choudhary, Pratik; Jones, Peter M.; Persaud, Shanta J.

    2016-01-01

    Background Although in vivo studies have implicated endocannabinoids in metabolic dysfunction, little is known about direct, chronic activation of the endocannabinoid system (ECS) in human islets. Therefore, this study investigated the effects of prolonged exposure to cannabinoid agonists on human islet gene expression and function. Methods Human islets were maintained for 2 and 5 days in the absence or presence of CB1r (ACEA) or CB2r (JWH015) agonists. Gene expression was quantified by RT-PCR, hormone levels by radioimmunoassay and apoptosis by caspase activities. Results Human islets express an ECS, with mRNAs encoding the biosynthetic and degrading enzymes NAPE-PLD, FAAH and MAGL being considerably more abundant than DAGLα, an enzyme involved in 2-AG synthesis, or CB1 and CB2 receptor mRNAs. Prolonged activation of CB1r and CB2r altered expression of mRNAs encoding ECS components, but did not have major effects on islet hormone secretion. JWH015 enhanced insulin and glucagon content at 2 days, but had no effect after 5 days. Treatment with ACEA or JWH015 for up to 5 days did not have marked effects on islet viability, as assessed by morphology and caspase activities. Conclusions Maintenance of human islets for up to 5 days in the presence of CB1 and CB2 receptor agonists causes modifications in ECS element gene expression, but does not have any major impact on islet function or viability. General Significance These data suggest that the metabolic dysfunction associated with over-activation of the ECS in obesity and diabetes in humans is unlikely to be secondary to impaired islet function. PMID:27114924

  1. MedlinePlus: Islet Cell Transplantation

    MedlinePlus

    ... Human Islet Transplantation. Islet Cell Transplantation -- see more articles Topic Image MedlinePlus Email Updates Get Islet Cell Transplantation updates by email What's this? GO GO National Institutes of Health The primary NIH organization for research on Islet Cell Transplantation is the ...

  2. Individual differences in psychostimulant responses of female rats are associated with ovarian hormones and dopamine neuroanatomy

    PubMed Central

    Walker, Q. David; Johnson, Misha L.; Van Swearingen, Amanda E.D.; Arrant, Andrew E.; Caster, Joseph M.; Kuhn, Cynthia M.

    2012-01-01

    Ovarian hormones modulate the pharmacological effects of psychostimulants and may enhance vulnerability to drug addiction. Female rats have more midbrain dopamine neurons than males and greater dopamine uptake and release rates. Cocaine stimulates motor behavior and dopamine efflux more in female than male rats, but the mediating mechanisms are unknown. This study investigated individual differences in anatomic, neurochemical, and behavioral measures in female rats to understand how ovarian hormones affect the relatedness of these endpoints. Ovarian hormone effects were assessed by comparing individual responses in ovariectomized (OVX) and sham adult female rats. Locomotion was determined before and following 10 mg/kg cocaine. Electrically-stimulated dopamine efflux was assessed using fast cyclic voltammetry in vivo. Dopamine neuron number and density in substantia nigra (SN) and ventral tegmental area (VTA) were determined in the same animals using tyrosine-hydroxylase immunohistochemistry and unbiased stereology. Locomotor behavior and dopamine efflux did not differ at baseline but were greater in sham than OVX following cocaine. Cocaine increased dopamine release rates in both groups but uptake inhibition (Km) was greater in sham than OVX. Dopamine neuron number and density in SN and VTA were greater in shams. Sham females with the largest uterine weights exhibited the highest density of dopamine neurons in the SN, and the most cocaine-stimulated behavior and dopamine efflux. Ovariectomy eliminated these relationships. We postulate that SN density could link ovarian hormones and high-psychostimulant responses in females. Similar mechanisms may be involved in individual differences in the addiction vulnerability of women. PMID:22342988

  3. Hormonal contraceptive use diminishes salivary cortisol response to psychosocial stress and naltrexone in healthy women

    PubMed Central

    Roche, Daniel J.O.; King, Andrea C.; Cohoon, Andrew J.; Lovallo, William R.

    2013-01-01

    The use of hormonal contraception (HC) may affect salivary cortisol levels at rest and in response to a pharmacological or stress challenge. Therefore, the current study used a secondary data analysis to investigate the effect of HC on salivary cortisol levels in response to the mu-opioid receptor antagonist naltrexone and a psychosocial stressor, and also across the diurnal curve. Two hundred and nine women (n = 72 using hormonal contraception; HC+) completed a two-session stress response study that consisted of a stress day, in which they were exposed to public speaking and mental arithmetic, and a rest day, in which unstimulated cortisol levels were measured to assess the diurnal rhythm. A subset of seventy women (n = 24 HC+) also completed a second study in which they were administered oral naltrexone (50 mg) or placebo in a randomized, placebo-controlled, double blind fashion. Women who were HC+ had a significantly reduced salivary cortisol response to both the psychosocial stressor (p < 0.001) and naltrexone (p < 0.05) compared to HC− women. Additionally, HC+ women had a significantly altered morning diurnal cortisol rhythm (p < 0.01), with a delayed peak and higher overall levels. The results of the current study confirm that HC attenuates salivary cortisol response to a psychosocial stressor and mu-opioid receptor antagonism, and also alters the morning diurnal cortisol curve. PMID:23672966

  4. Hormonal responses to exercise after partial sleep deprivation and after a hypnotic drug-induced sleep.

    PubMed

    Mougin, F; Bourdin, H; Simon-Rigaud, M L; Nguyen, N U; Kantelip, J P; Davenne, D

    2001-02-01

    The aim of this study was to determine the hormonal responses, which are dependent on the sleep wake cycle, to strenuous physical exercise. Exercise was performed after different nocturnal regimens: (i) a baseline night preceded by a habituation night; (ii) two nights of partial sleep deprivation caused by a delayed bedtime or by an early awakening; and (iii) two nights of sleep after administration of either a hypnotic compound (10 mg zolpidem) or a placebo. Eight well-trained male endurance athletes with a maximal oxygen uptake of 63.5 +/- 3.8 ml x kg(-1) x min(-1) (mean value +/- s(x)) were selected on the basis of their sleeping habits and their physical training. Polygraphic recordings of EEG showed that both nights with partial sleep loss led to a decrease (P< 0.01) in stage 2 and rapid eye movement sleep. A delayed bedtime also led to a decrease (P < 0.05) in stage 1 sleep. Zolpidem had no effect on the different stages of sleep. During the afternoon after an experimental night, exercise was performed on a cycle ergometer. After a 10-min warm-up, the participants performed 30 min steady-state cycling at 75% VO(2-max) followed by a progressively increased workload until exhaustion. The recovery period lasted 30 min. Plasma growth hormone, prolactin, cortisol, catecholamine and lactate concentrations were measured at rest, during exercise and after recovery. The concentration of plasma growth hormone and catecholamine were not affected by partial sleep deprivation, whereas that of plasma prolactin was higher (P < 0.05) during the trial after an early awakening. Plasma cortisol was lower (P < 0.05) during recovery after both sleep deprivation conditions. Blood lactate was higher (P < 0.05) during submaximal exercise performed after both a delayed bedtime and an early awakening. Zolpidem-induced sleep did not affect the hormonal and metabolic responses to subsequent exercise. Our results demonstrate only minor alterations in the hormonal responses to exercise

  5. Regulation of glucose turnover and hormonal responses during electrical cycling in tetraplegic humans.

    PubMed

    Kjaer, M; Pollack, S F; Mohr, T; Weiss, H; Gleim, G W; Bach, F W; Nicolaisen, T; Galbo, H; Ragnarsson, K T

    1996-07-01

    To examine the importance of blood-borne vs. neural mechanisms for hormonal responses and substrate mobilization during exercise, six spinal cord-injured tetraplegic (C5-T1) males (mean age: 35 yr, range: 24-55 yr) were recruited to perform involuntary, electrically induced cycling [functional electrical stimulation (FES)] to fatigue for 24.6 +/- 2.3 min (mean and SE), and heart rate rose from 67 +/- 7 (rest) to 107 +/- 5 (exercise) beats/min. Voluntary arm cranking in tetraplegics (ARM) and voluntary leg cycling in six matched, long-term immobilized (2-12 mo) males (Vol) served as control experiments. In FES, peripheral glucose uptake increased [12.4 +/- 1.1 (rest) to 19.5 +/- 4.3 (exercise) mumol.min-1.kg-1; P < 0.05], whereas hepatic glucose production did not change from basal values [12.4 +/- 1.4 (rest) vs. 13.0 +/- 3.4 (exercise) mumol.min-1.kg-1]. Accordingly, plasma glucose decreased [from 5.4 +/- 0.3 (rest) to 4.7 +/- 0.3 (exercise) mmol/l; P < 0.05]. Plasma glucose did not change in response to ARM or Vol. Plasma free fatty acids and beta-hydroxybutyrate decreased only in FES experiments (P < 0.05). During FES, increases in growth hormone (GH) and epinephrine and decreases in insulin concentrations were abolished. Although subnormal throughout the exercise period, norepinephrine concentrations increased during FES, and responses of heart rate, adrenocorticotropic hormone, beta-endorphin, renin, lactate, and potassium were marked. In conclusion, during exercise, activity in motor centers and afferent muscle nerves is important for normal responses of GH, catecholamines, insulin, glucose production, and lipolysis. Humoral feedback and spinal or simple autonomic nervous reflex mechanisms are not sufficient. However, such mechanisms are involved in redundant control of heart rate and neuroendocrine activity in exercise. PMID:8760220

  6. Pancreatic Islet-Like Three-Dimensional Aggregates Derived From Human Embryonic Stem Cells Ameliorate Hyperglycemia in Streptozotocin-Induced Diabetic Mice.

    PubMed

    Shim, Joong-Hyun; Kim, JongHyun; Han, Jiyou; An, Su Yeon; Jang, Yu Jin; Son, Jeongsang; Woo, Dong-Hun; Kim, Suel-Kee; Kim, Jong-Hoon

    2015-01-01

    We previously reported the in vitro differentiation of human embryonic stem cells (hESCs) into pancreatic endoderm. Here we demonstrate that islet-like three-dimensional (3D) aggregates can be derived from the pancreatic endoderm by optimizing our previous protocol. Sequential treatment with Wnt3a, activin A, and noggin induced a transient upregulation of T and MixL1, followed by increased expression of endodermal genes, including FOXA2, SOX17, and CXCR4. Subsequent treatment with retinoic acid highly upregulated PDX1 expression. We also show that inhibition of sonic hedgehog signaling by bFGF/activin βB and cotreatment with VEGF and FGF7 produced many 3D cellular clusters that express both SOX17 and PDX1. We found for the first time that proteoglycans and vimentin(+) mesenchymal cells were mainly localized in hESC-derived PDX1(+) clusters. Importantly, treatment with chlorate, an inhibitor of proteoglycan sulfation, together with inhibition of Notch signaling significantly increased the expression of Neurog3 and NeuroD1, promoting a transition from PDX1(+) progenitor cells toward mature pancreatic endocrine cells. Purified dithizone(+) 3D aggregates generated by our refined protocol produced pancreatic hormones and released insulin in response to both glucose and pharmacological drugs in vitro. Furthermore, the islet-like 3D aggregates decreased blood glucose levels and continued to exhibit pancreatic features after transplantation into diabetic mice. Generation of islet-like 3D cell aggregates from human pluripotent stem cells may overcome the shortage of cadaveric donor islets for future cases of clinical islet transplantation. PMID:25397866

  7. Salivary Hormones Response to Preparation and Pre-competitive Training of World-class Level Athletes

    PubMed Central

    Guilhem, Gaël; Hanon, Christine; Gendreau, Nicolas; Bonneau, Dominique; Guével, Arnaud; Chennaoui, Mounir

    2015-01-01

    This study aimed to compare the response of salivary hormones of track and field athletes induced by preparation and pre-competitive training periods in an attempt to comment on the physiological effects consistent with the responses of each of the proteins measured. Salivary testosterone, cortisol, alpha-amylase, immunoglobulin A (IgA), chromogranin A, blood creatine kinase activity, and profile of mood state were assessed at rest in 24 world-class level athletes during preparation (3 times in 3 months) and pre-competitive (5 times in 5 weeks) training periods. Total mood disturbance and fatigue perception were reduced, while IgA (+61%) and creatine kinase activity (+43%) increased, and chromogranin A decreased (−27%) during pre-competitive compared to preparation period. A significant increase in salivary testosterone (+9 to +15%) and a decrease in testosterone/cortisol ratio were associated with a progressive reduction in training load during pre-competitive period (P < 0.05). None of the psycho-physiological parameters were significantly correlated to training load during the pre-competitive period. Results showed a lower adrenocortical response and autonomic activity, and an improvement of immunity status, in response to the reduction in training load and fatigue, without significant correlations of salivary hormones with training load. Our findings suggest that saliva composition is sensitive to training contents (season period) but could not be related to workload resulting from track and field athletics training. PMID:26635619

  8. Islet inflammation in plain sight

    PubMed Central

    Abdulreda, Midhat H.; Berggren, Per-Olof

    2013-01-01

    Although, diabetes is reaching pandemic proportions, the exact etiology of either type 1 (T1D) or type 2 diabetes (T2D) remains to be determined. Mounting evidence, however, suggests that islet inflammation is a likely common denominator during early development of either type of the disease. In this review, we highlight some of the inflammatory mechanisms that appear to be shared between T1D and T2D, and we explore the utility of intravital imaging in the study of islet inflammation. Intravital imaging has emerged as an indispensable tool in biomedical research and a variety of in vivo imaging approaches have been developed to study pancreatic islet physiology and pathophysiology in the native environment in health and disease. However, given the scattered distribution of the islets of Langerhans within the “sea” of the exocrine pancreas located deep within the body and the fact that the islets only constitute 1 – 2% of the total volume of pancreatic tissue, studying the pancreatic islet in situ has been challenging. Here, we focus on a new experimental approach that enables studying local islet inflammation with single cell-resolution in the relevant context of the in vivo environment non-invasively and longitudinally and, thereby improving our understanding of diabetes pathogenesis. PMID:24003927

  9. Short term response of insulin, glucose, growth hormone and corticosterone to acute vibration in rats.

    NASA Technical Reports Server (NTRS)

    Dolkas, C. B.; Leon, H. A.; Chackerian, M.

    1971-01-01

    Study carried out to obtain some notion of the initial phasing and interactive effects among some hormones known to be responsive to vibration stress. Sprague-Dawley derived rats were exposed to the acute effects of confinement and confinement with lateral (plus or minus G sub y) vibration. The coincident monitoring of glucose, insulin, growth hormone, and corticosterone plasma levels, during and immediately subsequent to exposure to brief low level vibration, exhibits the effects of inhibition of insulin release by epinephrine. The ability of insulin (IRI) to return rapidly to basal levels, from appreciably depressed levels during vibration, in the face of elevated levels of glucose is also shown. Corticosterone responds with almost equal rapidity, but in opposite phase to the IRI. The immuno-assayable growth hormone (IGH) dropped from a basal level of 32 ng/ml to 7.3 ng/ml immediately subsequent to vibration and remained at essentially that level throughout the experiment (60 min). Whether these levels represent a real fall in the rat or whether they merely follow the immuno-logically deficient form is still in question.

  10. Multifollicular ovaries: clinical and endocrine features and response to pulsatile gonadotropin releasing hormone.

    PubMed

    Adams, J; Franks, S; Polson, D W; Mason, H D; Abdulwahid, N; Tucker, M; Morris, D V; Price, J; Jacobs, H S

    By means of pelvic ultrasonography, a multifollicular ovarian appearance was observed in women with weight-loss-related amenorrhoea. Multifollicular ovaries (MFO) are normal in size or slightly enlarged and filled by six or more cysts 4-10 mm in diameter; in contrast to women with polycystic ovaries (PCO), stroma is not increased. Unlike PCO patients, women with MFO were not hirsute and serum concentrations of luteinising hormone and follicle stimulating hormone were normal and decreased, respectively. The uterus was small indicating oestrogen deficiency. In MFO, treatment with gonadotropin releasing hormone (LHRH) induced ovulation in 83% of cycles and there were seven pregnancies in 8 women; in PCO, only 40% of cycles were ovulatory and there were eleven pregnancies (8 women) but six of these aborted. In MFO ovarian morphology reverted to normal in ovulatory cycles, whereas in PCO the polycystic pattern persisted despite the presence of a dominant follicle. MFO may represent a normal ovarian response to weight-related hypothalamic disturbance of gonadotropin control. PMID:2867389

  11. Psychological reactivity to laboratory stress is associated with hormonal responses in postmenopausal women

    PubMed Central

    Fang, Carolyn Y.; Egleston, Brian L.; Manzur, Angelica M.; Townsend, Raymond R.; Stanczyk, Frank Z.; Spiegel, David; Dorgan, Joanne F.

    2014-01-01

    OBJECTIVE The present study examined associations between psychological reactivity and hormonal responses to a standardized laboratory stressor (the Trier Social Stress Test [TSST]) in postmenopausal women. METHODS Forty postmenopausal women ages 50–74 completed anxiety and mood assessments prior to and following the TSST. Blood samples were drawn across multiple time points for assessment of cortisol, adrenocorticotropic hormone (ACTH), and DHEA. RESULTS As expected, significant increases in anxiety and negative affect and decreases in positive affect were observed from pre- to post-TSST; however, the magnitude of change in anxiety and mood varied considerably across individuals. Analyses indicated that greater increases in anxiety and negative affect from pre- to post-TSST were associated with higher levels of cortisol, ACTH, and DHEA, controlling for race, age, body mass index, and smoking status. Changes in positive affect were not associated with cortisol, ACTH, or DHEA. CONCLUSIONS These findings suggest that enhanced reactivity to stress is associated with higher hormone levels among postmenopausal women, which could have potential implications for health. PMID:24595153

  12. Lung-Derived Microscaffolds Facilitate Diabetes Reversal after Mouse and Human Intraperitoneal Islet Transplantation

    PubMed Central

    Pawlick, Rena L.; Kahana, Meygal; Pepper, Andrew R.; Bruni, Antonio; Gala-Lopez, Boris; Kin, Tatsuya; Mitrani, Eduardo; Shapiro, A. M. James

    2016-01-01

    There is a need to develop three-dimensional structures that mimic the natural islet tissue microenvironment. Endocrine micro-pancreata (EMPs) made up of acellular organ-derived micro-scaffolds seeded with human islets have been shown to express high levels of key beta-cell specific genes and secrete quantities of insulin per cell similar to freshly isolated human islets in a glucose-regulated manner for more than three months in vitro. The aim of this study was to investigate the capacity of EMPs to restore euglycemia in vivo after transplantation of mouse or human islets in chemically diabetic mice. We proposed that the organ-derived EMPs would restore the extracellular components of the islet microenvironment, generating favorable conditions for islet function and survival. EMPs seeded with 500 mouse islets were implanted intraperitoneally into streptozotocin-induced diabetic mice and reverted diabetes in 67% of mice compared to 13% of controls (p = 0.018, n = 9 per group). Histological analysis of the explanted grafts 60 days post-transplantation stained positive for insulin and exhibited increased vascular density in a collagen-rich background. EMPs were also seeded with human islets and transplanted into the peritoneal cavity of immune-deficient diabetic mice at 250 islet equivalents (IEQ), 500 IEQ and 1000 IEQ. Escalating islet dose increased rates of normoglycemia (50% of the 500 IEQ group and 75% of the 1000 IEQ group, n = 3 per group). Human c-peptide levels were detected 90 days post-transplantation in a dose-response relationship. Herein, we report reversal of diabetes in mice by intraperitoneal transplantation of human islet seeded on EMPs with a human islet dose as low as 500 IEQ. PMID:27227978

  13. Functional studies of rat, porcine, and human pancreatic islets cultured in ten commercially available media.

    PubMed

    Holmes, M A; Clayton, H A; Chadwick, D R; Bell, P R; London, N J; James, R F

    1995-10-27

    There have been no extensive studies investigating the effect of tissue culture media on the in vitro functional characteristics of rat, porcine and human Islets of Langerhans. We therefore aimed to compare ten commercially available tissue culture media on the basis of their ability to maintain islet viability. Following isolation, islets were cultured free-floating in the ten media (RPMI 1640-11mM glucose (control), RPMI 1640-2.2mM glucose, Dulbecco's MEM, TCM 199, CMRL 1066, Iscove's MEM, Waymouth's MEM, Serum-Free medium, Ex-cell 300, Ham's F-12) and viability was assessed after 24 hr, 3 days, and 7 days on the basis of macroscopic appearance, cell membrane integrity, and insulin secretion in response to glucose stimulation both by dynamic incubation and by perifusion. Each islet species demonstrated physiological insulin release characteristics in all media--however, it was possible to distinguish between the media by comparing the stimulation indices calculated from the insulin release studies. Significantly higher stimulation indices were produced in Iscove's MEM for rat islets, in Ham's F-12 for porcine islets and in CMRL 1066 for human islets. Over the entire culture period a significant deterioration in function was observed in all species cultured in the control media, although this was reversed when islets were cultured in the optimal media. Furthermore, in the case of porcine and human islets a significant improvement in function over the seven-day period was noted in the optimal media. In conclusion, of the commercially available media, the optimal tissue culture medium for rat islets is Iscove's MEM, for porcine islets is Ham's F-12, and for human islets is CMRL 1066. PMID:7482747

  14. Efficient Gene Transduction of Dispersed Islet Cells in Culture Using Fiber-Modified Adenoviral Vectors.

    PubMed

    Hanayama, Hiroyuki; Ohashi, Kazuo; Utoh, Rie; Shimizu, Hirofumi; Ise, Kazuya; Sakurai, Fuminori; Mizuguchi, Hiroyuki; Tsuchiya, Hiroyuki; Okano, Teruo; Gotoh, Mitsukazu

    2015-12-17

    To establish novel islet-based therapies, our group has recently developed technologies for creating functional neo-islet tissues in the subcutaneous space by transplanting monolithic sheets of dispersed islet cells (islet cell sheets). Improving cellular function and viability are the next important challenges for enhancing the therapeutic effects. This article describes the adenoviral vector-mediated gene transduction of dispersed islet cells under culture conditions. Purified pancreatic islets were obtained from Lewis rats and dissociated into single islet cells. Cells were plated onto laminin-5-coated temperature-responsive polymer poly(N-isopropylacrylamide)-immobilized plastic dishes. At 0 h, islet cells were infected for 1 h with either conventional type 5 adenoviral vector (Ad-CA-GFP) or fiber-modified adenoviral vector (AdK7-CA-GFP) harboring a polylysine (K7) peptide in the C terminus of the fiber knob. We investigated gene transduction efficiency at 48 h after infection and found that AdK7-CA-GFP yielded higher transduction efficiencies than Ad-CA-GFP at a multiplicity of infection (MOI) of 5 and 10. For AdK7-CA-GFP at MOI = 10, 84.4 ± 1.5% of islet cells were found to be genetically transduced without marked vector infection-related cellular damage as determined by viable cell number and lactate dehydrogenase (LDH) release assay. After AdK7-CA-GFP infection at MOI = 10, cells remained attached and expanded to nearly full confluency, showing that this adenoviral infection protocol is a feasible approach for creating islet cell sheets. We have shown that dispersed and cultured islet cells can be genetically modified efficiently using fiber-modified adenoviral vectors. Therefore, this gene therapy technique could be used for cellular modification or biological assessment of dispersed islet cells. PMID:26858906

  15. Lung-Derived Microscaffolds Facilitate Diabetes Reversal after Mouse and Human Intraperitoneal Islet Transplantation.

    PubMed

    Abualhassan, Nasser; Sapozhnikov, Lena; Pawlick, Rena L; Kahana, Meygal; Pepper, Andrew R; Bruni, Antonio; Gala-Lopez, Boris; Kin, Tatsuya; Mitrani, Eduardo; Shapiro, A M James

    2016-01-01

    There is a need to develop three-dimensional structures that mimic the natural islet tissue microenvironment. Endocrine micro-pancreata (EMPs) made up of acellular organ-derived micro-scaffolds seeded with human islets have been shown to express high levels of key beta-cell specific genes and secrete quantities of insulin per cell similar to freshly isolated human islets in a glucose-regulated manner for more than three months in vitro. The aim of this study was to investigate the capacity of EMPs to restore euglycemia in vivo after transplantation of mouse or human islets in chemically diabetic mice. We proposed that the organ-derived EMPs would restore the extracellular components of the islet microenvironment, generating favorable conditions for islet function and survival. EMPs seeded with 500 mouse islets were implanted intraperitoneally into streptozotocin-induced diabetic mice and reverted diabetes in 67% of mice compared to 13% of controls (p = 0.018, n = 9 per group). Histological analysis of the explanted grafts 60 days post-transplantation stained positive for insulin and exhibited increased vascular density in a collagen-rich background. EMPs were also seeded with human islets and transplanted into the peritoneal cavity of immune-deficient diabetic mice at 250 islet equivalents (IEQ), 500 IEQ and 1000 IEQ. Escalating islet dose increased rates of normoglycemia (50% of the 500 IEQ group and 75% of the 1000 IEQ group, n = 3 per group). Human c-peptide levels were detected 90 days post-transplantation in a dose-response relationship. Herein, we report reversal of diabetes in mice by intraperitoneal transplantation of human islet seeded on EMPs with a human islet dose as low as 500 IEQ. PMID:27227978

  16. Efficient Gene Transduction of Dispersed Islet Cells in Culture Using Fiber-Modified Adenoviral Vectors

    PubMed Central

    Hanayama, Hiroyuki; Ohashi, Kazuo; Utoh, Rie; Shimizu, Hirofumi; Ise, Kazuya; Sakurai, Fuminori; Mizuguchi, Hiroyuki; Tsuchiya, Hiroyuki; Okano, Teruo; Gotoh, Mitsukazu

    2015-01-01

    To establish novel islet-based therapies, our group has recently developed technologies for creating functional neo-islet tissues in the subcutaneous space by transplanting monolithic sheets of dispersed islet cells (islet cell sheets). Improving cellular function and viability are the next important challenges for enhancing the therapeutic effects. This article describes the adenoviral vector-mediated gene transduction of dispersed islet cells under culture conditions. Purified pancreatic islets were obtained from Lewis rats and dissociated into single islet cells. Cells were plated onto laminin-5-coated temperature-responsive polymer poly(N-isopropylacrylamide)-immobilized plastic dishes. At 0 h, islet cells were infected for 1 h with either conventional type 5 adenoviral vector (Ad-CA-GFP) or fiber-modified adenoviral vector (AdK7-CA-GFP) harboring a polylysine (K7) peptide in the C terminus of the fiber knob. We investigated gene transduction efficiency at 48 h after infection and found that AdK7-CA-GFP yielded higher transduction efficiencies than Ad-CA-GFP at a multiplicity of infection (MOI) of 5 and 10. For AdK7-CA-GFP at MOI = 10, 84.4 ± 1.5% of islet cells were found to be genetically transduced without marked vector infection-related cellular damage as determined by viable cell number and lactate dehydrogenase (LDH) release assay. After AdK7-CA-GFP infection at MOI = 10, cells remained attached and expanded to nearly full confluency, showing that this adenoviral infection protocol is a feasible approach for creating islet cell sheets. We have shown that dispersed and cultured islet cells can be genetically modified efficiently using fiber-modified adenoviral vectors. Therefore, this gene therapy technique could be used for cellular modification or biological assessment of dispersed islet cells. PMID:26858906

  17. Influence of alcohol on the hydromineral hormone responses to exercise in a warm environment.

    PubMed

    Saini, J; Boisvert, P; Spiegel, K; Candas, V; Brandenberger, G

    1995-01-01

    Alcohol consumption at rest is associated with disturbed water and salt regulation reflected by changed responses in the hydromineral hormones. This study investigated the effect of alcohol on endocrine systems involved in body fluid and electrolyte regulation under conditions of physical exercise in the heat, a situation in which under normal circumstances, the hydromineral hormones are stimulated in an attempt to preserve physiological homeostasis. Eight healthy male volunteers participated in two trials, which differed only in the presence or absence of alcohol (1.2 g alcohol.kg-1 body mass) in a cocktail drink. After consuming the cocktail, the subjects exercised for 60 min on a cycle ergometer (45% maximal oxygen consumption) at 35 degrees C. Compared to the control situation alcohol consumption (maximal plasma concentrations reaching about 1.08 g.l-1) produced an increase in body fluid loss (P < 0.05), but did not induce significant differences in plasma volume changes. Plasma volume decreased in both sessions during exercise (P < 0.01) and a significant rebound (P < 0.001) occurred during recovery. Osmolality was significantly higher (P < 0.001) during rest, exercise and recovery periods compared to the placebo trials, but no effect of alcohol on plasma Na+ and K+ concentrations was observed. In the alcohol test conditions, the arginine vasopressin (AVP) response to exercise was significantly dampened (P < 0.05). In contrast, alcohol had no effect on aldosterone or atrial natriuretic peptide (ANP). These results demonstrated that alcohol ingestion augmented body fluid losses due to a suppressive effect on AVP during physical exercise conducted in a warm environment. The increase in osmolality due to alcohol did not influence the aldosterone and ANP responses, which would suggest that total osmolality does not play a major role in the regulation of these hormones. PMID:8789567

  18. Stress Response Circuitry Hypoactivation Related to Hormonal Dysfunction in Women with Major Depression

    PubMed Central

    Holsen, Laura M.; Spaeth, Sarah B.; Lee, Jong-Hwan; Ogden, Lauren A.; Klibanski, Anne; Whitfield-Gabrieli, Susan; Goldstein, Jill M.

    2011-01-01

    Background Women have approximately twice the risk of major depressive disorder (MDD) than men, yet this difference remains largely unexplained. Previous MDD research suggests high rates of endocrine dysfunction, which may be related to deficits in brain activity in stress response circuitry [hypothalamus, amygdala, hippocampus, anterior cingulate cortex (ACC), orbitofrontal cortex (OFC)]. This functional magnetic resonance imaging (fMRI) study investigated the relationship between hypothalamic-pituitary-gonadal (HPG)-axis hormones and stress response circuitry dysfunction in MDD in women. Methods During the late follicular/midcycle phase of the menstrual cycle, female participants (10 with extensive histories of MDD, in remission, 10 healthy controls) were scanned while viewing negative and neutral arousal pictures. Group differences in blood oxygen-level dependent (BOLD) signal changes were analyzed using SPM2. Baseline gonadal hormones included estradiol, progesterone, and testosterone. Results fMRI results showed greater BOLD signal intensity changes in controls versus MDD in hypothalamus, amygdala, hippocampus, OFC, ACC, and subgenual ACC, findings unrelated to medication status. MDD women had a lower serum estradiol and higher serum progesterone compared to controls. Hypoactivations in hypothalamus, subgenual ACC, amygdala and OFC in MDD were associated with low estradiol and high progesterone. Limitations Generalizability of our findings is limited by small sample size and restriction to females, although this did not affect the internal validity of the results. Conclusions Hypoactivation of the stress response circuitry in MDD women is associated with dysregulation of the HPG-axis. Associations between brain activity deficits and hormonal disruption in MDD may ultimately contribute to understanding sex differences in MDD. PMID:21183223

  19. The lizard fauna of Guam's fringing islets: Island biogeography, phylogenetic history, and conservation implications

    USGS Publications Warehouse

    Perry, G.; Rodda, G.H.; Fritts, T.H.; Sharp, T.R.

    1998-01-01

    We sampled the lizard fauna of twenty-two small islets fringing the Pacific island of Guam and used these data to shed light on the processes responsible for present-day diversity. Habitat diversity, measured by islet area and vegetation complexity, was significantly correlated with the number of species found on an islet. However, islet distance and elevation were not significant predictors of diversity. Distribution patterns were slightly different for the two major families in our sample, Scincidae and Gekkonidae: skinks needed larger islets to maintain a population than did geckos. Presence/absence patterns were highly and significantly nested, and population density was correlated with the number of islets on which a species was found. An area cladogram was poorly supported and showed no faunal similarity between nearby islands. These patterns indicate that extinctions on most islets were due mostly to non-catastrophic, long-acting biological causes. The presence on the islets of species extirpated on Guam and the lack of significant nestedness on islands with greater maximum elevation highlight the impact that predators (primarily brown treesnakes) can have. Our findings also show that small reserves will not suffice to protect endangered lizard faunas, and that the islets may serve as a short-term repository of such species until snake-free areas can be established on Guam.

  20. Beta-cell metabolic alterations under chronic nutrient overload in rat and human islets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to assess multifactorial Beta-cell responses to metabolic perturbations in primary rat and human islets. Treatment of dispersed rat islet cells with elevated glucose and free fatty acids (FFAs, oleate:palmitate = 1:1 v/v) resulted in increases in the size and the number of ...

  1. Central serotonin transporter levels are associated with stress hormone response and anxiety

    PubMed Central

    Reimold, Matthias; Knobel, Astrid; Rapp, Michael A.; Batra, Anil; Wiedemann, Klaus; Ströhle, Andreas; Zimmer, Anke; Schönknecht, Peter; Smolka, Michael N.; Weinberger, Daniel R.; Goldman, David; Machulla, Hans-Jürgen; Bares, Roland; Heinz, Andreas

    2010-01-01

    Rationale Negative mood states are characterized by both stress hormone dysregulation and serotonergic dysfunction, reflected by altered thalamic serotonin transporter (5-HTT) levels. However, so far, no study examined the individual association between cortisol response and cerebral in vivo 5-HTT levels in patients suffering from negative mood states. Objective The objective of this cross-sectional study was to assess the interrelation of cortisol response, thalamic 5-HTT levels, and anxiety in healthy subjects and two previously published samples of patients with unipolar major depression (UMD) and obsessive–compulsive disorder (OCD), controlling for age, gender, 5-HTT genotype, smoking, and seasonality. Methods Regional 5-HTT levels and cortisol response to dexamethasone-corticotropin (Dex-CRH) challenge were assessed in consecutive samples of medication-free patients suffering from UMD (N=10) and OCD (N=10), and 20 healthy volunteers. The intervention used was combined Dex-CRH test and [11C]DASB positron emission tomography. The main outcome measures were: 5-HTT binding potential (BPND) in a predefined thalamic ROI, cortisol response defined as the maximum cortisol increase in the combined Dex-CRH-test, and state of anxiety from the state-trait-anxiety inventory. Results Reduced thalamic 5-HTT BPND was associated with increased cortisol response (r=−0.35, p<0.05; in patients: r=−0.53, p<0.01) and with increased state anxiety (r=−0.46, p<0.01), surviving correction for age, gender, 5-HTT genotype, smoking, and seasonality (p<0.05). The 5-HTT genotype, on the contrary, was not significantly associated with cortisol response (p=0.19) or negative mood (p=0.23). Conclusion The association between stress hormone response, thalamic 5-HTT levels, and anxiety in patients suffering from negative mood states suggests an interaction between two major mechanisms implicated in negative mood states in humans. PMID:20585760

  2. Human islet preparations distributed for research exhibit a variety of insulin-secretory profiles

    PubMed Central

    Kayton, Nora S.; Poffenberger, Gregory; Henske, Joseph; Dai, Chunhua; Thompson, Courtney; Aramandla, Radhika; Shostak, Alena; Nicholson, Wendell; Brissova, Marcela; Bush, William S.

    2015-01-01

    Human islet research is providing new insights into human islet biology and diabetes, using islets isolated at multiple US centers from donors with varying characteristics. This creates challenges for understanding, interpreting, and integrating research findings from the many laboratories that use these islets. In what is, to our knowledge, the first standardized assessment of human islet preparations from multiple isolation centers, we measured insulin secretion from 202 preparations isolated at 15 centers over 11 years and noted five distinct patterns of insulin secretion. Approximately three quarters were appropriately responsive to stimuli, but one quarter were dysfunctional, with unstable basal insulin secretion and/or an impairment in stimulated insulin secretion. Importantly, the patterns of insulin secretion by responsive human islet preparations (stable Baseline and Fold stimulation of insulin secretion) isolated at different centers were similar and improved slightly over the years studied. When all preparations studied were considered, basal and stimulated insulin secretion did not correlate with isolation center, biological differences of the islet donor, or differences in isolation, such as Cold Ischemia Time. Dysfunctional islet preparations could not be predicted from the information provided by the isolation center and had altered expression of genes encoding components of the glucose-sensing pathway, but not of insulin production or cell death. These results indicate that insulin secretion by most preparations from multiple centers is similar but that in vitro responsiveness of human islets cannot be predicted, necessitating preexperimental human islet assessment. These results should be considered when one is designing, interpreting, and integrating experiments using human islets. PMID:25648831

  3. Human islet preparations distributed for research exhibit a variety of insulin-secretory profiles.

    PubMed

    Kayton, Nora S; Poffenberger, Gregory; Henske, Joseph; Dai, Chunhua; Thompson, Courtney; Aramandla, Radhika; Shostak, Alena; Nicholson, Wendell; Brissova, Marcela; Bush, William S; Powers, Alvin C

    2015-04-01

    Human islet research is providing new insights into human islet biology and diabetes, using islets isolated at multiple US centers from donors with varying characteristics. This creates challenges for understanding, interpreting, and integrating research findings from the many laboratories that use these islets. In what is, to our knowledge, the first standardized assessment of human islet preparations from multiple isolation centers, we measured insulin secretion from 202 preparations isolated at 15 centers over 11 years and noted five distinct patterns of insulin secretion. Approximately three quarters were appropriately responsive to stimuli, but one quarter were dysfunctional, with unstable basal insulin secretion and/or an impairment in stimulated insulin secretion. Importantly, the patterns of insulin secretion by responsive human islet preparations (stable Baseline and Fold stimulation of insulin secretion) isolated at different centers were similar and improved slightly over the years studied. When all preparations studied were considered, basal and stimulated insulin secretion did not correlate with isolation center, biological differences of the islet donor, or differences in isolation, such as Cold Ischemia Time. Dysfunctional islet preparations could not be predicted from the information provided by the isolation center and had altered expression of genes encoding components of the glucose-sensing pathway, but not of insulin production or cell death. These results indicate that insulin secretion by most preparations from multiple centers is similar but that in vitro responsiveness of human islets cannot be predicted, necessitating preexperimental human islet assessment. These results should be considered when one is designing, interpreting, and integrating experiments using human islets. PMID:25648831

  4. Pituitary response to thyrotropin releasing hormone in children with overweight and obesity.

    PubMed

    Rijks, Jesse; Penders, Bas; Dorenbos, Elke; Straetemans, Saartje; Gerver, Willem-Jan; Vreugdenhil, Anita

    2016-01-01

    Thyroid stimulating hormone (TSH) concentrations in the high normal range are common in children with overweight and obesity, and associated with increased cardiovascular disease risk. Prior studies aiming at unravelling the mechanisms underlying these high TSH concentrations mainly focused on factors promoting thyrotropin releasing hormone (TRH) production as a cause for high TSH concentrations. However, it is unknown whether TSH release of the pituitary in response to TRH is affected in children with overweight and obesity. Here we describe TSH release of the pituitary in response to exogenous TRH in 73 euthyroid children (39% males) with overweight or (morbid) obesity. Baseline TSH concentrations (0.9-5.5 mU/L) were not associated with BMI z score, whereas these concentrations were positively associated with TSH concentrations 20 minutes after TRH administration (r(2) = 0.484, p < 0.001) and the TSH incremental area under the curve during the TRH stimulation test (r(2) = 0.307, p < 0.001). These results suggest that pituitary TSH release in response to TRH stimulation might be an important factor contributing to high normal serum TSH concentrations, which is a regular finding in children with overweight and obesity. The clinical significance and the intermediate factors contributing to pituitary TSH release need to be elucidated in future studies. PMID:27485208

  5. The hypothalamic-pituitary response in SLE. Regulation of prolactin, growth hormone and cortisol release.

    PubMed

    Rovenský, J; Blazícková, S; Rauová, L; Jezová, D; Koska, J; Lukác, J; Vigas, M

    1998-01-01

    It has been suggested that neuroendocrine regulation plays an important role in the pathogenesis and activation of autoimmune diseases. The aim of this investigation was to clarify the hypothalamic-pituitary response to a well-defined stimulus under standardised conditions in patients with SLE. Plasma concentrations of prolactin (PRL), growth hormone (GH) and cortisol were determined in venous blood drawn through an indwelling cannula during insulin-induced hypoglycaemia (0.1 U/kg b.w., i.v.) in ten patients and in 12 age-, gender- and weight-matched healthy subjects. Basal PRL concentrations were higher in patients vs healthy controls (12 vs 6 ng/ml, P < 0.01), though still within the physiological range. Insulin-induced plasma PRL and GH were significantly increased both in patients and healthy subjects; however, the increments or areas under the curves were not different in the two groups. Plasma cortisol response showed moderate attenuation in patients. Sensitivity of pituitary lactotrothrops to thyrotropin-releasing hormone (TRH) administration (200 microg, i.v.) was the same in patients and control subjects. In SLE patients with low activity of the disease the sensitivity of pituitary PRL release to TRH administration remained unchanged. The hypothalamic response to stress stimulus (hypoglycaemia) was comparable in patients and healthy subjects. PMID:9736325

  6. Pituitary response to thyrotropin releasing hormone in children with overweight and obesity

    PubMed Central

    Rijks, Jesse; Penders, Bas; Dorenbos, Elke; Straetemans, Saartje; Gerver, Willem-Jan; Vreugdenhil, Anita

    2016-01-01

    Thyroid stimulating hormone (TSH) concentrations in the high normal range are common in children with overweight and obesity, and associated with increased cardiovascular disease risk. Prior studies aiming at unravelling the mechanisms underlying these high TSH concentrations mainly focused on factors promoting thyrotropin releasing hormone (TRH) production as a cause for high TSH concentrations. However, it is unknown whether TSH release of the pituitary in response to TRH is affected in children with overweight and obesity. Here we describe TSH release of the pituitary in response to exogenous TRH in 73 euthyroid children (39% males) with overweight or (morbid) obesity. Baseline TSH concentrations (0.9–5.5 mU/L) were not associated with BMI z score, whereas these concentrations were positively associated with TSH concentrations 20 minutes after TRH administration (r2 = 0.484, p < 0.001) and the TSH incremental area under the curve during the TRH stimulation test (r2 = 0.307, p < 0.001). These results suggest that pituitary TSH release in response to TRH stimulation might be an important factor contributing to high normal serum TSH concentrations, which is a regular finding in children with overweight and obesity. The clinical significance and the intermediate factors contributing to pituitary TSH release need to be elucidated in future studies. PMID:27485208

  7. Characterization of the Human Pancreatic Islet Proteome by Two-Dimensional LC/MS/MS

    PubMed Central

    Metz, Thomas O.; Jacobs, Jon M.; Gritsenko, Marina A.; Fontès, Ghislaine; Qian, Wei-Jun; Camp, David G.; Poitout, Vincent; Smith, Richard D.

    2010-01-01

    The pancreatic beta-cell plays a central role in the maintenance of glucose homeostasis and in the pathogenesis of both type 1 and type 2 diabetes mellitus. Elucidation of the insulin secretory defects observed in diabetes first requires a better understanding of the complex mechanisms regulating insulin secretion, which are only partly understood. While there have been reports detailing proteomic analyses of islet cell lines or isolated rodent islets, the information gained is not always applicable to humans. Therefore, definition of the human islet proteome could contribute to a better understanding of islet biology and lead to more effective treatment strategies. We have applied a two-dimensional LC-MS/MS-based analysis to the characterization of the human islet proteome, resulting in the confident identification of 29,021 different tryptic peptides covering 3,365 proteins (≥ 2 unique peptide identifications per protein). As expected, the three major islet hormones (insulin, glucagon, and somatostatin) were detected, as well as various beta-cell enriched secretory products, ion channels, and transcription factors. In addition, significant proteome coverage of metabolic enzymes and cellular pathways was observed, including the integrin signaling cascade and the MAP kinase, NF-κβ, and JAK/STAT pathways. The resulting peptide reference library provides a resource for future higher throughput and quantitative studies of islet biology. PMID:17137336

  8. Differentiation of embryonic stem cells to insulin-secreting structures similar to pancreatic islets.

    PubMed

    Lumelsky, N; Blondel, O; Laeng, P; Velasco, I; Ravin, R; McKay, R

    2001-05-18

    Although the source of embryonic stem (ES) cells presents ethical concerns, their use may lead to many clinical benefits if differentiated cell types can be derived from them and used to assemble functional organs. In pancreas, insulin is produced and secreted by specialized structures, islets of Langerhans. Diabetes, which affects 16 million people in the United States, results from abnormal function of pancreatic islets. We have generated cells expressing insulin and other pancreatic endocrine hormones from mouse ES cells. The cells self-assemble to form three-dimensional clusters similar in topology to normal pancreatic islets where pancreatic cell types are in close association with neurons. Glucose triggers insulin release from these cell clusters by mechanisms similar to those employed in vivo. When injected into diabetic mice, the insulin-producing cells undergo rapid vascularization and maintain a clustered, islet-like organization. PMID:11326082

  9. Association of follicle stimulating hormone receptor promoter with ovarian response in IVF-ET patients

    PubMed Central

    Dan, Wang; Jing, Gao; Liangbin, Xia; Ting, Zhang; Ying, Zeng

    2015-01-01

    Background: Poor ovarian response phenomenon has been observed in some of the in vitro fertilization-embryo transfer patients. Some investigations found that follicle stimulating hormone receptor (FSHR) gene plays a role in the process, but no direct evidence shows the correlation between genotypes of FSHR and ovarian response. Objective: Exploring the molecular mechanism behind the mutation of FSHR promoter association with ovarian granulosa cells and poor ovarian response. Materials and Methods: This cross sectional study was performed using 158 women undergoing the controlled short program ovarian stimulation for IVF treatment. The 263 bp DNA fragments before the follicle stimulating hormone (FSH) receptor 5' initiation site were sequenced in the patients under IVF cycle, 70 of which had poor ovarian response and 88 showed normal ovarian responses. Results: With a mutation rate of 40%, 63 in 158 cases showed a 29th site G→A point mutation; among the mutated cases, the mutation rate of the poor ovarian responders was significantly higher than the normal group (60% versus 23.9%; χ2=21.450, p<0.001). Besides, the variability was also obvious in antral follicle count, and ovum pick-ups. The estradiol peak values and the number of mature eggs between the two groups had significant difference. However, there was no obvious variability (t=0.457, p=0.324) in the basic FSH values between the two groups (normal group, 7.2±2.3 U/L; mutation group, 7.1±2.0 U/L). Conclusion: The activity of FSHR promoter is significantly affected by the 29th site G→A mutation that will weaken promoter activity and result in poor response to FSH. PMID:26730247

  10. Fibrillar dimer formation of islet amyloid polypeptides

    NASA Astrophysics Data System (ADS)

    Chiu, Chi-cheng; de Pablo, Juan J.

    2015-09-01

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 - 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 - 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  11. Fibrillar dimer formation of islet amyloid polypeptides

    SciTech Connect

    Chiu, Chi-cheng; de Pablo, Juan J.

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  12. Severe short stature and Wolf-Hirschhorn syndrome: response to growth hormone in two cases without growth hormone deficiency.

    PubMed

    Austin, Devon E; Gunn, Alistair J; Jefferies, Craig A

    2015-02-01

    Wolf-Hirschhorn syndrome (WHS) is a rare congenital disorder occurring in approximately 1/50 000 births, with marked pre- and postnatal growth failure. WHS results from the hemizygous deletion encompassing the 4p16.3 region. This report of two children with WHS shows that growth hormone treatment in selected children with WHS and severe short stature may have a substantial effect on long-term growth. PMID:25988083

  13. Biosynthesis of glucagon in isolated pancreatic islets of guinea pigs

    PubMed Central

    Hellerström, Claes; Howell, Simon L.; Edwards, John C.; Andersson, Arne; Östenson, Claes-Göran

    1974-01-01

    1. The biosynthesis of glucagon in guinea-pig A2 cells was investigated by incubation of isolated islets of Langerhans in the presence of [3H]tryptophan for periods of up to 14 days. Proteins were extracted from islets and incubation media and analysed by gel filtration. 2. In addition to very-high-molecular-weight (100000) proteins, the principal tryptophan-containing biosynthetic product after incubation for up to 17h was a protein of minimum mol.wt. 9000, which co-eluted on gel filtration with a peak of glucagon-like immunoreactivity, but was apparently devoid of biological activity in a fat-cell assay. A discrete peak of labelled glucagon was only recovered after incubation for at least 6 days. Losses of glucagon during the extraction and rapid secretion of newly synthesized glucagon into incubation media were excluded as reasons for the lack of recovery of labelled hormone from islets after shorter incubations. 3. The 9000-mol.wt. protein was localized to A2 cells in experiments using B-cell-depleted islets, and to A2-cell granules by subcellular fractionation and electron-microscopic radioautography. Only glucagon was secreted into the incubation medium. 4. Possible relationships between the 9000-mol.wt. protein and glucagon are discussed in the light of postulated mechanisms of glucagon biosynthesis. PMID:4615708

  14. Head-up tilt and lower body suction: comparison of hormone responses in healthy men.

    PubMed

    Hinghofer-Szalkay, H G; Vigas, M; Sauseng-Fellegger, G; König, E M; Lichardus, B; Jezová, D

    1996-01-01

    The purpose of this study was to compare, in the same subjects, hormonal responses to 30-min head-up tilt (HUT) and lower body suction (LBNP) of different intensity (24 degrees and 70 degrees, and 15 and 35 mm Hg, respectively). Basal pooled individual data from -10 min (n = 32) were within normal reference limits: norepinephrine (NE) averaged 318 +/- 23 pg/ml; epinephrine, 34.0 +/- 5.5 pg/ml; plasma renin activity (PRA), 0.72 +/- 0.08 ng ATII/ml/h; aldosterone, 164 +/- 20 pg/ml; atrial natriuretic peptide (ANP), 29.9 +/- 2.0 pg/ml; cGMP, 6.29 +/- 0.59 mmol/l; cortisol, 95.7 +/- 5.8 ng/ml; and ACTH, 50.3 +/- 2.6 pg/ml. The low-level stimuli failed to induce consistent changes in hormone levels. From the onset of the stimulus (minute 0) to its termination (minute 30), norepinephrine (NE) increased by 101% with LBNP-35, and by 70% with HUT70, respectively. The NE increase with LBNP-35 was higher (p < 0.05) than with HUT70. Epinephrine rose with HUT70 (by 162%) only. PRA increased by 157% with LBNP-35, and by 119% with HUT70, respectively; these responses were not significantly different. Aldosterone rose equally (by 85 and 89%) with LBNP-35 and HUT70 but not with the low-level stimuli. No consistent changes were observed in ANP, c-GMP or ACTH concentrations. Cortisol values fell during the LBNP and HUT24 situations but rose transiently after HUT70. We conclude that the hormones investigated respond differently to head-up posture and lower body suction and in a specific manner. Greater effects of high-level stimuli (HUT70, LBNP-35) were noted as compared to low-level stimuli (HUT24, LBNP-15). The application of combined sets of models stimulating the cardiovascular system may aid in the analysis of responses of hormonal systems in man. PMID:9085364

  15. Sex differences, hormones, and fMRI stress response circuitry deficits in psychoses

    PubMed Central

    Goldstein, Jill M.; Lancaster, Katie; Longenecker, Julia M.; Abbs, Brandon; Holsen, Laura M.; Cherkerzian, Sara; Whitfield-Gabrieli, Susan; Makris, Nicolas; Tsuang, Ming T.; Buka, Stephen L.; Seidman, Larry J.; Klibanski, Anne

    2015-01-01

    Psychosis involves dysregulation of response to stress, particularly to negative valence stimuli. Functional magnetic resonance imaging studies of psychosis have shown hyperactivity in hypothalamus, hippocampus, amygdala, and anterior cingulate cortex, and orbitofrontal and medial prefrontal cortices. Sex differences in these deficits may be associated with steroid hormone pathway abnormalities, i.e., dysregulation of the hypothalamic pituitary-adrenal and -gondal axes. We predicted abnormal steroid hormone levels in psychosis cases would be associated with hyperactivity in hypothalamus, amygdala, and hippocampus, and hypoactivity in prefrontal and anterior cingulate cortices in a sex-dependent way, with more severe deficits in men than women with psychosis. We studied 32 psychosis cases (50.0% women) and 39 controls (43.6% women) using a novel visual stress challenge while collecting blood throughout functional magnetic resonance imaging procedures. Males with psychosis showed hyperactivity across all hypothesized regions, including the hypothalamus and anterior cingulate cortex by family-wise corrected significance. Females showed hyperactivity in the hippocampus and amygdala and hypoactivity in orbital and medial prefrontal cortices, the latter by family-wise correction. Interaction of case status by sex was significant in the medial prefrontal cortex and, marginally so, in the left orbitofrontal cortex, with female cases (vs. healthy females and males) exhibiting the lowest activity. Male and female cases compared with their healthy counterparts were hypercortisolemic, which was associated with hyperactivity in prefrontal cortices in male cases and hypoactivity in female cases. This was further associated, respectively, with low bioavailable testosterone in male cases and low estradiol in female cases. Findings suggest disruptions in neural-hormone associations in response to stress are sex-dependent in psychosis, particularly in the prefrontal cortex. PMID

  16. Comparison of Neutral Proteases and Collagenase Class I as Essential Enzymes for Human Islet Isolation

    PubMed Central

    Brandhorst, Heide; Kurfürst, Manfred; Johnson, Paul R.; Korsgren, Olle; Brandhorst, Daniel

    2016-01-01

    Background Efficient islet isolation requires synergistic interaction between collagenase class I (CI) and class II (CII). The CI degradation alters the ratio between CI and CII and is responsible for batch-to-batch variations. This study compares the role of neutral protease (NP) plus clostripain (CP) with CI as essential enzymes for human islet isolation. Methods Human islets were isolated using 4 different enzyme mixtures composed of CII plus either intact (CI-115) or degraded CI (CI-100). Blends were administered either with or without NP/CP. Purified islets were cultured for 3 to 4 days before islet quality assessment. Results Whereas using intact CI-115 without NP/CP did not significantly reduce islet yield (3429 ± 631 vs 3087 ± 970 islet equivalent/g, nonsignificant), administration of degraded CI-100 without NP/CP decreased islet yield from 3501 ± 580 to 1312 ± 244 islet equivalent/g (P < 0.01), doubled the amount of undigested tissue from 11.8 ± 1.6 to 24.4 ± 1.2% (P < 0.01) and triplicated the percentage of trapped islets from 7.7 ± 2.8 to 22.5 ± 3.6% (P < 0.05). Islet yield did not vary between supplemented CI-115 and CI-100, but was increased using CI-115 when NP/CP was omitted (P < 0.05). A trend toward higher viability and increased secretory insulin response was noted in both CI-100 and CI-115 when NP/CP was not added. Conclusions This study suggests that NP/CP can compensate reduced CI activity. Future attempts to optimize enzyme blends should consider the possibility to increase the proportion of collagenase CI to reduce the need for potentially harmful NPs. PMID:27500241

  17. Islet amyloid polypeptide is expressed in the pancreatic islet parenchyma of the teleostean fish, Myoxocephalus (cottus) scorpius.

    PubMed

    Westermark, Gunilla T; Falkmer, Sture; Steiner, Donald F; Chan, Shu Jin; Engström, Ulla; Westermark, Per

    2002-09-01

    The comparative endocrinology of the 37-amino-acid-residue islet amyloid polypeptide (IAPP) is poorly known, possibly due to the fact that available antisera, raised against mammalian IAPP, fail to give immunoreactivity with islet parenchymal cells of non-mammalian vertebrates. Using reverse transcriptase-linked polymerase chain reaction with degenerate primers, IAPP was identified, and its deduced amino-acid sequence partially characterized, in three species of teleostean fish, i.e. Danio rerio (zebrafish), Salmo salar (Atlantic salmon), and Myoxocephalus (cottus) scorpius (daddy sculpin). The daddy sculpin is a species where the histophysiology of the pancreatic islet parenchyma has previously been comprehensively studied. From the deduced amino-acid sequence, a synthetic peptide, corresponding to positions 20-29 of Salmo IAPP, was synthesized. A mouse antiserum to this peptide gave a distinct immunoreactivity with the insulin-producing beta cells of the sculpin Brockmann bodies and salmon endocrine pancreas. Thus, IAPP belongs to the group of peptide hormones expressed by the islet parenchymal cells in both mammals and non-mammalian vertebrates. Salmo salar IAPP(20-29) was found to give rise to amyloid-like fibrils in vitro. PMID:12223219

  18. Acute hormonal responses before and after 2 weeks of HIT in well trained junior triathletes.

    PubMed

    Zinner, C; Wahl, P; Achtzehn, S; Reed, J L; Mester, J

    2014-04-01

    The aim was to compare the acute hormonal response to a single HIT session at the beginning and end of a HIT shock microcycle. 13 male junior triathletes (15.8±1.8 yrs.) performed 16 HIT sessions within a 2 week period. Venous blood samples were collected before and after the first and last HIT session. Significant increases in cortisol (first session +89.7%; last session +70.3%) and hGH (first session +435.1%; last session +314.6%) concentrations were observed after both training sessions (P<0.05). The acute responses of cortisol, hGH, T3, and fT3 were not different between the first and last HIT sessions (P=1.00). Although no acute changes in testosterone were detected after the training sessions, testosterone concentrations were significantly higher at all time points (62.6-80.1%) during the last compared to first training session (P≤0.001). Findings from the present study reveal that 16 sessions of HIT led to significant increases in baseline concentrations of serum testosterone. This might indicate a heightened anabolic state even in junior triathletes. Based on the hormonal data, we conclude that at the end of this 2 week microcycle no familiarization effect was evident and that the training stimulus produced by HIT was still great enough to "stress" the athletes and induce positive training adaptations. PMID:24081622

  19. Neuromuscular, hormonal, and metabolic responses to different plyometric training volumes in rugby players.

    PubMed

    Cadore, Eduardo L; Pinheiro, Eraldo; Izquierdo, Mikel; Correa, Cleiton S; Radaelli, Régis; Martins, Jocelito B; Lhullier, Francisco L R; Laitano, Orlando; Cardoso, Marcelo; Pinto, Ronei S

    2013-11-01

    The purpose of this study was to investigate the effect of different volumes of plyometric exercise (i.e., 100, 200, or 300 hurdle jumps) on acute strength and jump performance and on the acute hormonal and lactate responses in rugby players. Eleven young male elite rugby players (age, 23.5 ± 0.9 years; height, 173 ± 4.8 cm) volunteered for the study. Maximal isometric peak torque (PT), maximal rate of force development (RFD), squat jump (SJ), and drop jump (DJ) performance were assessed before and 5 minutes, 8 hours, and 24 hours after 100, 200, or 300 jumps. In addition, total testosterone (TT), cortisol (COR), and lactate were measured before and after the 3 different plyometric exercise volumes. There were significant decreases in the PT (p < 0.02) and maximal RFD (p < 0.001) 5 minutes, 8 hours, and 24 hours after 100, 200, and 300 jumps, with no differences between the exercise volumes. Additionally, there were significant decreases in the SJ (p < 0.001) and DJ (p < 0.01) performances 24 hours after 100, 200, and 300 jumps, with no differences between the exercise volumes. However, there were significant increases in the TT (p < 0.001), COR (p < 0.05), and lactate (p < 0.001) after 100, 200, and 300 jumps, with no differences between the exercise volumes. All plyometric exercise volumes (100, 200, and 300 jumps) resulted in similar neuromuscular, metabolic, and hormonal responses. PMID:23442289

  20. Hormonal and electrolyte responses to acute isohemic volume expansion in unanesthetized rats

    NASA Technical Reports Server (NTRS)

    Chenault, V. M.; Morris, M.; Lynch, C. D.; Maultsby, S. J.; Hutchins, P. M.

    1993-01-01

    This study was undertaken to explore the time course of the metabolic response to isohemic blood volume expansion (30%) in normotensive, unanesthetized Sprague-Dawley rats. Whole blood, drawn from a femoral artery catheter of conscious donor rats, was infused into the jugular vein of recipient rats. Blood samples were drawn from a carotid artery of recipient rats at time points beginning immediately post-volume expansion (IPVE) up through 5 days post-volume expansion (PVE). To characterize the attendant compensatory mechanisms, the plasma concentrations of electrolytes and fluid regulatory hormones were determined. Hematocrit began to raise IPVE and was significantly elevated above control IPVE 20, 30, 40, 60, and 90 min, and 2, 4, 6, 8, 12, and 24 hr PVE. Consistent with our current understanding of the hormonal response to excess volume, atrial natriuretic factor was significantly increased above the prevolume expansion (control) values 0-30 min PVE. Surprisingly, plasma aldosterone levels were significantly increased above control at 20 and 30 min and 6 hr PVE, whereas plasma renin activity was significantly decreased 30-40 min PVE. Plasma sodium was not changed from control values except for a significant increase at 6 hr post-volume expansion. Plasma potassium, osmolality, and arginine vasopressin levels were not altered by the volume expansion. These studies delineate the physiologic time scheme operative in the regulation of fluid volume during acute ischemic volume expansion.

  1. Microfluidic Device for the Measurement of Amino Acid Secretion Dynamics from Murine and Human Islets of Langerhans.

    PubMed

    Wang, Xue; Yi, Lian; Roper, Michael G

    2016-03-15

    Islets of Langerhans are the regulators of in vivo blood glucose levels through the secretion of endocrine hormones. Amino acids, released from various cells within islets or from intrapancreatic neurons, are hypothesized to further adjust hormone secretions. In contrast to the well-accepted mechanism of glucose-stimulated insulin secretion, several questions remain as to the function of amino acids in the regulation of hormone release from islets. To understand the autocrine and paracrine roles that amino acids play in islet physiology, a microfluidic system was developed to perform online monitoring of the secretion profiles of amino acids from 2-5 islets. The device contained an islet chamber with the ability to perfuse stimulants and an amino acid measurement system with derivatization and electrophoretic separation integrated on a single microchip. The setup was optimized to allow -15 kV to be applied to the device for high efficiency and rapid separations of derivatized amino acids. The compositions of the derivatization and separation buffers were optimized to prevent precipitations in the channels, which allowed continuous monitoring of secretion for over 2 h. With this method, 10 amino acids were resolved with limits of detection ranging from 1 to 20 nM. When murine islets were perfused with 3 mM glucose, the secretion rates of 9 amino acids were measured and ranged from 30 to 400 fmol islet(-1) min(-1). As the glucose concentration was increased to 20 mM, the dynamic changes of amino acids were monitored. The biological relevance of the amino acid secretions was verified using 2,4-dinitrophenol as an inhibitor of the proton motive force. The microfluidic system was also used to measure dynamic changes of amino acid release from human islets, which showed different release profiles compared to their murine counterparts. PMID:26891222

  2. Altered radiation responses of breast cancer cells resistant to hormonal therapy

    PubMed Central

    Luzhna, Lidiya; Lykkesfeldt, Anne E.; Kovalchuk, Olga

    2015-01-01

    Endocrine therapy agents (the selective estrogen receptor (ER) modulators such as tamoxifen or the selective ER down-regulators such as ICI 182,780) are key treatment regimens for hormone receptor-positive breast cancers. While these drugs are very effective in controlling ER-positive breast cancer, many tumors that initially respond well to treatment often acquire drug resistance, which is a major clinical problem. In clinical practice, hormonal therapy agents are commonly used in combination or sequence with radiation therapy. Tamoxifen treatment and radiotherapy improve both local tumor control and patient survival. However, tamoxifen treatment may render cancer cells less responsive to radiation therapy. Only a handful of data exist on the effects of radiation on cells resistant to hormonal therapy agents. These scarce data show that cells that were resistant to tamoxifen were also resistant to radiation. Yet, the existence and mechanisms of cross-resistance to endocrine therapy and radiation therapy need to be established. Here, we for the first time examined and compared radiation responses of MCF-7 breast adenocarcinoma cells (MCF-7/S0.5) and two antiestrogen resistant cell lines derived from MCF-7/S0.5: the tamoxifen resistant MCF-7/TAMR-1 and ICI 182,780 resistant MCF-7/182R-6 cell lines. Specifically, we analyzed the radiation-induced changes in the expression of genes involved in DNA damage, apoptosis, and cell cycle regulation. We found that the tamoxifen-resistant cell line in contrast to the parental and ICI 182,780-resistant cell lines displayed a significantly less radiation-induced decrease in the expression of genes involved in DNA repair. Furthermore, we show that MCF-7/TAMR-1 and MCF-7/182R-6 cells were less susceptible to radiation-induced apoptosis as compared to the parental line. These data indicate that tamoxifen-resistant breast cancer cells have a reduced sensitivity to radiation treatment. The current study may therefore serve as a

  3. The use of biomaterials in islet transplantation.

    PubMed

    Borg, Danielle J; Bonifacio, Ezio

    2011-10-01

    Pancreatic islet transplantation is a therapeutic option to replace destroyed β cells in autoimmune diabetes. Islets are transplanted into the liver via the portal vein; however, inflammation, the required immunosuppression, and lack of vasculature decrease early islet viability and function. Therefore, the use of accessory therapy and biomaterials to protect islets and improve islet function has definite therapeutic potential. Here we review the application of niche accessory cells and factors, as well as the use of biomaterials as carriers or capsules, for pancreatic islet transplantation. PMID:21748257

  4. Characterization of the mouse pancreatic islet proteome and comparative analysis with other mouse tissues

    SciTech Connect

    Petyuk, Vladislav A.; Qian, Weijun; Hinault, Charlotte; Gritsenko, Marina A.; Singhal, Mudita; Monroe, Matthew E.; Camp, David G.; Kulkarni, Rohit N.; Smith, Richard D.

    2008-08-01

    The pancreatic islets of Langerhans and insulin-producing beta cells in particular play a central role in the maintenance of glucose homeostasis and the islet dysfunction is associated with the pathogenesis of both type 1 and type 2 diabetes mellitus. To contribute to the understanding of the biology of the pancreatic islets we applied proteomic techniques based on liquid chromatography coupled with mass spectrometry. Here as an initial step we present the first comprehensive proteomic characterization of pancreas islets of the mouse, the commonly used animal model for diabetes research. Two-dimensional SCX LC/RP LC-MS/MS has been applied to characterize of the mouse islet proteome, resulting in the confident identification of 17,350 different tryptic peptides covering 2,612 proteins with at least two unique peptide identifications per protein. The dataset also allowed identification of a number of post-translational modifications including several modifications relevant to oxidative stress and phosphorylation. While many of the identified phosphorylation sites corroborates with previous known sites, the oxidative modifications observed on cysteinyl residues potentially reveal novel information related to the role of oxidation stress in islet functions. Comparative analysis of the islet proteome database with 15 available proteomic datasets from other mouse tissues and cells revealed a set of 68 proteins uniquely detected only in the pancreatic islets. Besides proteins with known functions, like islet secreted peptide hormones, this unique set contains a number of proteins with yet unknown functions. The resulting peptide and protein database will be available at ncrr.pnl.gov web site of the NCRR proteomic center (ncrr.pnl.gov).

  5. Predicting Treatment Response for Oppositional Defiant and Conduct Disorder Using Pre-treatment Adrenal and Gonadal Hormones

    PubMed Central

    Shenk, Chad E.; Dorn, Lorah D.; Kolko, David J.; Susman, Elizabeth J.; Noll, Jennie G.; Bukstein, Oscar G.

    2016-01-01

    Variations in adrenal and gonadal hormone profiles have been linked to increased rates of oppositional defiant disorder (ODD) and conduct disorder (CD). These relationships suggest that certain hormone profiles may be related to how well children respond to psychological treatments for ODD and CD. The current study assessed whether pre-treatment profiles of adrenal and gonadal hormones predicted response to psychological treatment of ODD and CD. One hundred five children, 6 – 11 years old, participating in a randomized, clinical trial provided samples for cortisol, testosterone, dehydroepiandrosterone, and androstenedione. Diagnostic interviews of ODD and CD were administered up to three years post-treatment to track treatment response. Group-based trajectory modeling identified two trajectories of treatment response: 1) a High-response trajectory where children demonstrated lower rates of an ODD or CD diagnosis throughout follow-up, and 2) a Low-response trajectory where children demonstrated higher rates of an ODD or CD diagnosis throughout follow-up. Hierarchical logistic regression predicting treatment response demonstrated that children with higher pre-treatment concentrations of testosterone were four times more likely to be in the Low-response trajectory. No other significant relationship existed between pre-treatment hormone profiles and treatment response. These results suggest that higher concentrations of testosterone are related to how well children diagnosed with ODD or CD respond to psychological treatment over the course of three years.

  6. Acute metabolic, hormonal, and psychological responses to different endurance training protocols.

    PubMed

    Wahl, P; Mathes, S; Köhler, K; Achtzehn, S; Bloch, W; Mester, J

    2013-10-01

    In the last years, mainly 2 high-intensity-training (HIT) protocols became common: first, a Wingate-based "all-out" protocol and second, a 4×4 min protocol. However, no direct comparison between these protocols exists, and also a comparison with high-volume-training (HVT) is missing. Therefore, the aim of the present study was to compare these 3 endurance training protocols on metabolic, hormonal, and psychological responses. Twelve subjects performed: 1) HVT [130 min at 55% peak power output (PPO)]; 2) 4×4 min at 95% PPO; 3) 4×30 s all-out. Human growth hormone (hGH), testosterone, and cortisol were determined before (pre) and 0', 30', 60', 180' after each intervention. Metabolic stimuli and perturbations were characterized by lactate, blood gas (pH, BE, HCO₃⁻, pO₂, PCO₂), and spirometric analysis. Furthermore, changes of the person's perceived physical state were determined. The 4×30 s training caused the highest increases in cortisol and hGH, followed by 4 × 4 min and HVT. Testosterone levels were significantly increased by all 3 exercise protocols. Metabolic stress was highest during and after 4×30 s, followed by 4×4 min and HVT. The 4×30 s training was also the most demanding intervention from an athlete's point of view. In conclusion, the results suggest that 4×30 s and 4×4 min promote anabolic processes more than HVT, due to higher increases of hGH, testosterone, and the T/C ratio. It can be speculated that the acute hormonal increase and the metabolic perturbations might play a positive role in optimizing training adaptation and in eliciting health benefits as it has been shown by previous long term training studies using similar exercise protocols. PMID:23794400

  7. Sex dependent regulation of osteoblast response to implant surface properties by systemic hormones

    PubMed Central

    2010-01-01

    Background Osseointegration depends on the implant surface, bone quality and the local and systemic host environment, which can differ in male and female patients. This study was undertaken in order to determine if male and female cells respond differently to titanium surfaces that have micron-scale roughness and if interactions of calciotropic hormones [1α,25(OH)2D3 and 17β-oestradiol (E2)] and microstructured surfaces on osteoblasts are sex dependent. Methods Osteoblasts from 6-week old Sprague-Dawley rats were cultured on tissue culture polystyrene (TCPS) or on titanium (Ti) disks with two different surface topographies, a smooth pretreated (PT) surface and a coarse grit-blasted/acid-etched (SLA) surface, and treated with 1α,25(OH)2D3, E2, or E2 conjugated to bovine serum albumin (E2-BSA). Results Male and female cells responded similarly to Ti microstructure with respect to cell number and levels of osteocalcin, transforming growth factor-β1, osteoprotegerin and prostaglandin E2 in their conditioned media, exhibiting a more differentiated phenotype on SLA than on PT or TCPS. E2 and E2-BSA increased differentiation and local factor production, an effect that was microstructure dependent and found only in female osteoblasts. 1α,25(OH)2D3 increased osteoblast differentiation and local factor production in female and male cells, but the effect was more robust in male cells. Conclusions Male and female rat osteoblasts respond similarly to surface microstructure but exhibit sexual dimorphism in substrate-dependent responses to systemic hormones. Oestrogen affected only female cells while 1α,25(OH)2D3 had a greater effect on male cells. These results suggest that successful osseointegration in males and females may depend on the implant surface design and correct levels of calciotropic hormones. PMID:21208469

  8. Effect of inositol and tri-iodothyronine on the hormonal responsiveness of hepatocytes obtained from partially hepatectomized rats.

    PubMed Central

    Huerta-Bahena, J; García-Sáinz, J A

    1984-01-01

    Hepatocytes obtained from animals partially hepatectomized (72 h before the experiment) have a diminished responsiveness to alpha 1-adrenergic amines, vasopressin, angiotensin and glucagon and an increased responsiveness to beta-adrenergic amines. Administration of inositol or tri-iodothyronine to the hepatectomized animals induced a recovery in the hepatocyte responsiveness to the Ca2+-dependent hormones and abolished that to beta-adrenergic amines; the response to glucagon was not improved. PMID:6508748

  9. Electrofusion of mesenchymal stem cells and islet cells for diabetes therapy: a rat model.

    PubMed

    Yanai, Goichi; Hayashi, Takashi; Zhi, Qi; Yang, Kai-Chiang; Shirouzu, Yasumasa; Shimabukuro, Takashi; Hiura, Akihito; Inoue, Kazutomo; Sumi, Shoichiro

    2013-01-01

    Islet transplantation is a minimally invasive treatment for severe diabetes. However, it often requires multiple donors to accomplish insulin-independence and the long-term results are not yet satisfying. Therefore, novel ways to overcome these problems have been explored. Isolated islets are fragile and susceptible to pro-apoptotic factors and poorly proliferative. In contrast, mesenchymal stem cells (MSCs) are highly proliferative, anti-apoptotic and pluripotent to differentiate toward various cell types, promote angiogenesis and modulate inflammation, thereby studied as an enhancer of islet function and engraftment. Electrofusion is an efficient method of cell fusion and nuclear reprogramming occurs in hybrid cells between different cell types. Therefore, we hypothesized that electrofusion between MSC and islet cells may yield robust islet cells for diabetes therapy. We establish a method of electrofusion between dispersed islet cells and MSCs in rats. The fusion cells maintained glucose-responsive insulin release for 20 days in vitro. Renal subcapsular transplantation of fusion cells prepared from suboptimal islet mass (1,000 islets) that did not correct hyperglycemia even if co-transplanted with MSCs, caused slow but consistent lowering of blood glucose with significant weight gain within the observation period in streptozotocin-induced diabetic rats. In the fusion cells between rat islet cells and mouse MSCs, RT-PCR showed new expression of both rat MSC-related genes and mouse β-cell-related genes, indicating bidirectional reprogramming of both β-cell and MSCs nuclei. Moreover, decreased caspase3 expression and new expression of Ki-67 in the islet cell nuclei suggested alleviated apoptosis and gain of proliferative capability, respectively. These results show that electrofusion between MSCs and islet cells yield special cells with β-cell function and robustness of MSCs and seems feasible for novel therapeutic strategy for diabetes mellitus. PMID:23724055

  10. Pancreatic islet function in omega3 fatty acid-depleted rats: Glucose metabolism and nutrient-stimulated insulin release.

    PubMed

    Oguzhan, Berrin; Zhang, Ying; Louchami, Karim; Courtois, Philippe; Portois, Laurence; Chardigny, Jean-Michel; Malaisse, Willy J; Carpentier, Yvon A; Sener, Abdullah

    2006-06-01

    In order to gain information on the determinism of the perturbation of fuel homeostasis in situations characterized by a depletion in long-chain polyunsaturated omega3 fatty acids (omega3), the metabolic and hormonal status of omega3-depleted rats (second generation) was examined. When required, these rats were injected intravenously 120 min before sacrifice with a novel medium-chain triglyceride-fish oil emulsion able to provoke a rapid and sustained increase of the omega3 content in cell phospholipids. The measurement of plasma glucose, insulin, phospholipid, triglyceride, and unesterified fatty acid concentration indicated modest insulin resistance in the omega3-depleted rats. The plasma triglyceride and phospholipid concentrations were decreased in the omega3-depleted rats with abnormally low contribution of omega3 in both circulating and pancreatic islet lipids. The protein, insulin, and lipid content of the islets, as well as their intracellular and extracellular spaces, were little affected in the omega3-depleted rats. The metabolism of D-glucose in the islets of omega3-depleted rats was characterized by a lesser increase in D-[5-3H]glucose utilization and D-[U-14C]glucose oxidation in response to a given rise in hexose concentration and an abnormally low ratio between D-glucose oxidation and utilization. These abnormalities could be linked to an increased metabolism of endogenous fatty acids with resulting alteration of glucokinase kinetics. The release of insulin evoked by D-glucose, at a close-to-physiological concentration (8.3 mM), was increased in the omega3-depleted rats, this being considered as consistent with their insulin resistance. Relative to such a release, that evoked by a further rise in D-glucose concentration or by non-glucidic nutrients was abnormally high in omega3-depleted rats, and restored to a normal level after of the intravenous injection of the omega3-rich medium-chain triglyceride-fish oil emulsion. Because the latter procedure

  11. Peri-pubertal exposure to testicular hormones organizes response to novel environments and social behaviour in adult male rats

    PubMed Central

    Brown, Gillian R.; Kulbarsh, Kyle D.; Spencer, Karen A.; Duval, Camille

    2015-01-01

    Previous research has shown that exposure to testicular hormones during the peri-pubertal period of life has long-term, organizational effects on adult sexual behaviour and underlying neural mechanisms in laboratory rodents. However, the organizational effects of peri-pubertal testicular hormones on other aspects of behaviour and brain function are less well understood. Here, we investigated the effects of manipulating peri-pubertal testicular hormone exposure on later behavioural responses to novel environments and on hormone receptors in various brain regions that are involved in response to novelty. Male rodents generally spend less time in the exposed areas of novel environments than females, and this sex difference emerges during the peri-pubertal period. Male Lister-hooded rats (Rattus norvegicus) were castrated either before puberty or after puberty, then tested in three novel environments (elevated plus-maze, light–dark box, open field) and in an object/social novelty task in adulthood. Androgen receptor (AR), oestrogen receptor (ER1) and corticotropin-releasing factor receptor (CRF-R2) mRNA expression were quantified in the hypothalamus, hippocampus and medial amygdala. The results showed that pre-pubertally castrated males spent more time in the exposed areas of the elevated-plus maze and light–dark box than post-pubertally castrated males, and also confirmed that peri-pubertal hormone exposure influences later response to an opposite-sex conspecific. Hormone receptor gene expression levels did not differ between pre-pubertally and post-pubertally castrated males in any of the brain regions examined. This study therefore demonstrates that testicular hormone exposure during the peri-pubertal period masculinizes later response to novel environments, although the neural mechanisms remain to be fully elucidated. PMID:26159287

  12. The hyperbolic effect of density and strength of inter beta-cell coupling on islet bursting: a theoretical investigation

    PubMed Central

    Nittala, Aparna; Wang, Xujing

    2008-01-01

    Background Insulin, the principal regulating hormone of blood glucose, is released through the bursting of the pancreatic islets. Increasing evidence indicates the importance of islet morphostructure in its function, and the need of a quantitative investigation. Recently we have studied this problem from the perspective of islet bursting of insulin, utilizing a new 3D hexagonal closest packing (HCP) model of islet structure that we have developed. Quantitative non-linear dependence of islet function on its structure was found. In this study, we further investigate two key structural measures: the number of neighboring cells that each β-cell is coupled to, nc, and the coupling strength, gc. Results β-cell clusters of different sizes with number of β-cells nβ ranging from 1–343, nc from 0–12, and gc from 0–1000 pS, were simulated. Three functional measures of islet bursting characteristics – fraction of bursting β-cells fb, synchronization index λ, and bursting period Tb, were quantified. The results revealed a hyperbolic dependence on the combined effect of nc and gc. From this we propose to define a dimensionless cluster coupling index or CCI, as a composite measure for islet morphostructural integrity. We show that the robustness of islet oscillatory bursting depends on CCI, with all three functional measures fb, λ and Tb increasing monotonically with CCI when it is small, and plateau around CCI = 1. Conclusion CCI is a good islet function predictor. It has the potential of linking islet structure and function, and providing insight to identify therapeutic targets for the preservation and restoration of islet β-cell mass and function. PMID:18673579

  13. Growth hormone response to different consecutive stress stimuli in healthy men: is there any difference?

    PubMed

    Jezova, D; Radikova, Z; Vigas, M

    2007-06-01

    The contribution of growth hormone (GH), released during acute and repeated stressful situations, to the development of stress-related disorders is often neglected. We have hypothesized that the modulation of the GH response to sequential stress exposure in humans depends mainly on the nature of the stressor. To test this hypothesis, we compared GH responses to different stressful situations, namely aerobic exercise, hypoglycemia and hyperthermia, which were applied in two sequential sessions separated by 80-150 min. In addition, administration of the dopaminergic drug apomorphine was used as a pharmacological stimulus. GH responses to submaximal exercise (bicycle ergometer, increasing work loads of 1.5, 2.0 and 2.5 W/kg, total duration 20 min) and hyperthermia in a sauna (80 degrees C, 30 min) were prevented when preceded by the same stress stimulus. Hypoglycemia induced by insulin (0.1 IU/kg intravenously) resulted in a significant GH response also during the second of the two consecutive insulin tests, though the response was reduced. Administration of apomorphine (0.75 mg subcutaneously) or insulin prevented the increase in GH release in response to a sequential bolus of apomorphine, while hypoglycemia induced a significant elevation in GH levels even if applied after a previous treatment with apomorphine. In conclusion, the feedback inhibition of the GH response to a sequential stress stimulus depends on the stimulus used. Unlike in the case of exercise and hyperthermia, mechanisms involved in the stress response to hypoglycemia appear to overcome the usual feedback mechanisms and to re-induce the GH response when applied after another stimulus. PMID:17514589

  14. Modulation of. beta. -adrenergic response in rat brain astrocytes by serum and hormones

    SciTech Connect

    Wu, D.K.; Morrison, R.S.; de Vellis, J.

    1985-01-01

    Purified astrocyte cultures from neonatal rat cerebrum respond to isoproterenol, a ..beta..-adrenergic agonist, with a transient rise in cAMP production. This astroglial property was regulated by serum, a chemically defined medium (serum-free medium plus hydrocortisone, putrescine, prostaglandin F/sub 2/, insulin, and fibroblast growth factor) and epidermal growth factor. Compared to astrocytes grown in serum-supplemented medium, astrocytes grown in the chemically defined medium were nonresponsive to isoproterenol stimulation, and this difference did not appear to be due to selection of a subpopulation of cells by either medium. The data suggest that a decreased ..beta..-adrenergic receptor number and an increased degradation of cAMP may account for the reduced response to ..beta..-adrenergic stimulation. The nonresponsive state of astrocytes in the defined medium was reversible when the medium was replaced with serum-supplemented medium. An active substance(s) in serum was responsible for restoring the responsiveness of astrocytes. Each of the five components of the defined medium had little effect by itself; however, together they acted synergistically to desensitize astrocytes to ..beta..-adrenergic stimulation. On the other hand, epidermal growth factor, a potent mitogen for astrocytes, was very competent by itself in reducing the cAMP response of astrocytes to ..beta..-adrenergic stimulation. Thus purified astrocytes grown in the chemically defined medium appear to be a good model for the study of hormonal interactions and of serum factors which may modulate the ..beta..-adrenergic response.

  15. Parathyroid hormone modulates the response of osteoblast-like cells to mechanical stimulation

    NASA Technical Reports Server (NTRS)

    Ryder, K. D.; Duncan, R. L.

    2000-01-01

    Mechanical loading stimulates many responses in bone and osteoblasts associated with osteogenesis. Since loading and parathyroid hormone (PTH) activate similar signaling pathways in osteoblasts, we postulate that PTH can potentiate the effects of mechanical stimulation. Using an in vitro four-point bending device, we found that expression of COX-2, the inducible isoform of cyclooxygenase, was dependent on fluid forces generated across the culture plate, but not physiologic levels of strain in MC3T3-E1 osteoblast-like cells. Addition of 50 nM PTH during loading increased COX-2 expression at both subthreshold and threshold levels of fluid forces compared with either stimuli alone. We also demonstrated that application of fluid shear to MC3T3-E1 cells induced a rapid increase in [Ca(2+)](i). Although PTH did not significantly change [Ca(2+)](i) levels, flow and PTH did produce a significantly greater [Ca(2+)](i) response and increased the number of responding cells than is found in fluid shear alone. The [Ca(2+)](i) response to these stimuli was significantly decreased when the mechanosensitive channel inhibitor, gadolinium, was present. These studies indicate that PTH increases the cellular responses of osteoblasts to mechanical loading. Furthermore, this response may be mediated by alterations in [Ca(2+)](i) by modulating the mechanosensitive channel.

  16. Human islets contain four distinct subtypes of β cells.

    PubMed

    Dorrell, Craig; Schug, Jonathan; Canaday, Pamela S; Russ, Holger A; Tarlow, Branden D; Grompe, Maria T; Horton, Tamara; Hebrok, Matthias; Streeter, Philip R; Kaestner, Klaus H; Grompe, Markus

    2016-01-01

    Human pancreatic islets of Langerhans contain five distinct endocrine cell types, each producing a characteristic hormone. The dysfunction or loss of the insulin-producing β cells causes diabetes mellitus, a disease that harms millions. Until now, β cells were generally regarded as a single, homogenous cell population. Here we identify four antigenically distinct subtypes of human β cells, which we refer to as β1-4, and which are distinguished by differential expression of ST8SIA1 and CD9. These subpopulations are always present in normal adult islets and have diverse gene expression profiles and distinct basal and glucose-stimulated insulin secretion. Importantly, the β cell subtype distribution is profoundly altered in type 2 diabetes. These data suggest that this antigenically defined β cell heterogeneity is functionally and likely medically relevant. PMID:27399229

  17. The hepatic catabolic stress response. Hormonal regulation of urea synthesis after surgery.

    PubMed

    Heindorff, H A

    1993-04-01

    Following non complicated surgical trauma in man a hepatic condition has been identified that is characterized by lower than normal plasma alpha-amino nitrogen concentration and increased plasma clearance of gluconeogenic and ureagenic amino acids. Amino acids are removed from the blood by the liver, by way of a doubling of the hepatic efficacy fo urea synthesis. At any plasma amino acid concentration twice as much amino-nitrogen is excreted as urea-nitrogen, and thus lost for protein synthesis. This hepatic stress response lasts for one week postoperatively. In rats, hysterectomy elicits a similar response, but the time of the maximum increase in urea synthesis occurs earlier. Combined neuro-hormonal blockade totally prevents the response in cholecystectomized patients. In rats, it is preventable by selective blockades of glucocorticoid action and of prostaglandins synthesis. In isolated livers catecholamines, corticosterone, and glucagon together bring about 40% of the increase in urea synthesis in vivo, but only in livers "conditioned" by hysterectomy three hours earlier. Prostaglandin E2 in itself has no effect on urea synthesis, but accelerates the effect of the hormones. The regulatory system is incompletely elucidated, although several mediators are identified. A hierarchical system is suggested and discussed, and further possible regulators indicated. The role of liver for whole body nitrogen homeostasis during stress is estimated. The increase in hepatic efficacy for urea synthesis in itself accounts for about 50% of the postoperative nitrogen loss. Identification of the pathophysiological changes following surgical trauma is probably decisive for endeavours to improve postoperative morbidity and mortality. Modification of the hepatic contribution to postoperative loss of nitrogen may be necessary. PMID:8495598

  18. Hormone responses to a continuous bout of rock climbing in men.

    PubMed

    Sherk, Vanessa D; Sherk, Kyle A; Kim, SoJung; Young, Kaelin C; Bemben, Debra A

    2011-04-01

    Rock climbing is rapidly increasing in popularity as a recreational activity and as a competitive sport. Few studies have tested acute physiological responses to climbing, and no studies to date have tested hormone responses to a climbing-based workout. This study aimed to measure testosterone (T), growth hormone (GH), and cortisol (C) responses to continuous vertical climbing in young male rock climbers. Ten male rock climbers, aged between 21 and 30 years, climbed laps on a submaximal 55' climbing route for 30 min, or until exhaustion, whichever came first. Heart rate (HR) was recorded after every lap. Blood samples were collected by venipuncture before (Pre), immediately post (IP), and 15 min after the climbing exercise (P15) to assess blood lactate and plasma GH, T, and C. Subjects climbed 24.9 ± 1.9 min and 507.5 ± 82.5 feet. Peak HR was 182.1 ± 2.3 bpm, and lactate (Pre: 2.9 ± 0.6 mmol/dL, IP: 11.1 ± 1.0 mmol/dL) significantly (P < 0.05) increased from Pre to IP. T concentrations significantly (P < 0.05) increased from Pre (6.04 ± 0.31 ng/mL) to IP (7.39 ± 0.40 ng/mL) and returned to baseline at P15 (6.23 ± 0.33 ng/mL). Cortisol levels did not significantly change during the protocol. GH significantly (P < 0.01) increased from Pre (0.63 ± 0.17 ng/mL) to IP (19.89 ± 4.53 ng/mL) and remained elevated at P15 (15.03 ± 3.89 ng/mL). An acute, short-term bout of high-intensity continuous climbing was an effective exercise stimulus for elevating plasma testosterone and growth hormone levels in young males. PMID:20963437

  19. A system biology approach highlights a hormonal enhancer effect on regulation of genes in a nitrate responsive "biomodule"

    PubMed Central

    Nero, Damion; Krouk, Gabriel; Tranchina, Daniel; Coruzzi, Gloria M

    2009-01-01

    Background Nitrate-induced reprogramming of the transcriptome has recently been shown to be highly context dependent. Herein, a systems biology approach was developed to identify the components and role of cross-talk between nitrate and hormone signals, likely to be involved in the conditional response of NO3- signaling. Results Biclustering was used to identify a set of genes that are N-responsive across a range of Nitrogen (N)-treatment backgrounds (i.e. nitrogen treatments under different growth conditions) using a meta-dataset of 76 Affymetrix ATH1 chips from 5 different laboratories. Twenty-one biclusters were found to be N-responsive across subsets of this meta-dataset. N-bicluster 9 (126 genes) was selected for further analysis, as it was shown to be reproducibly responsive to NO3- as a signal, across a wide-variety of background conditions and datasets. N-bicluster 9 genes were then used as "seed" to identify putative cross-talk mechanisms between nitrate and hormone signaling. For this, the 126 nitrate-regulated genes in N-bicluster 9 were biclustered over a meta-dataset of 278 ATH1 chips spanning a variety of hormone treatments. This analysis divided the bicluster 9 genes into two classes: i) genes controlled by NO3- only vs. ii) genes controlled by both NO3- and hormones. The genes in the latter group showed a NO3- response that is significantly enhanced, compared to the former. In silico analysis identified two Cis-Regulatory Elements candidates (CRE) (E2F, HSE) potentially involved the interplay between NO3- and hormonal signals. Conclusion This systems analysis enabled us to derive a hypothesis in which hormone signals are proposed to enhance the nitrate response, providing a potential mechanistic explanation for the link between nitrate signaling and the control of plant development. PMID:19500399

  20. The Different Faces of the Pancreatic Islet.

    PubMed

    Abdulreda, Midhat H; Rodriguez-Diaz, Rayner; Cabrera, Over; Caicedo, Alejandro; Berggren, Per-Olof

    2016-01-01

    Type 1 diabetes (T1D) patients who receive pancreatic islet transplant experience significant improvement in their quality-of-life. This comes primarily through improved control of blood sugar levels, restored awareness of hypoglycemia, and prevention of serious and potentially life-threatening diabetes-associated complications, such as kidney failure, heart and vascular disease, stroke, nerve damage, and blindness. Therefore, beta cell replacement through transplantation of isolated islets is an important option in the treatment of T1D. However, lasting success of this promising therapy depends on durable survival and efficacy of the transplanted islets, which are directly influenced by the islet isolation procedures. Thus, isolating pancreatic islets with consistent and reliable quality is critical in the clinical application of islet transplantation.Quality of isolated islets is important in pre-clinical studies as well, as efforts to advance and improve clinical outcomes of islet transplant therapy have relied heavily on animal models ranging from rodents, to pigs, to nonhuman primates. As a result, pancreatic islets have been isolated from these and other species and used in a variety of in vitro or in vivo applications for this and other research purposes. Protocols for islet isolation have been somewhat similar across species, especially, in mammals. However, given the increasing evidence about the distinct structural and functional features of human and mouse islets, using similar methods of islet isolation may contribute to inconsistencies in the islet quality, immunogenicity, and experimental outcomes. This may also contribute to the discrepancies commonly observed between pre-clinical findings and clinical outcomes. Therefore, it is prudent to consider the particular features of pancreatic islets from different species when optimizing islet isolation protocols.In this chapter, we explore the structural and functional features of pancreatic islets from

  1. Review: Puberty as a time of remodeling the adult response to ovarian hormones.

    PubMed

    Blaustein, Jeffrey D; Ismail, Nafissa; Holder, Mary K

    2016-06-01

    During pubertal development, an animal's response to stress changes and sexual differentiation of the brain and behavior continue. We discovered that particular stressors, such as shipping from suppliers or an immune challenge with lipopolysaccharide, during the prolonged pubertal period of female mice result in long-term changes in behavioral responsiveness of the brain to estradiol assessed in adulthood. All behaviors influenced by estradiol and/or progesterone that we have studied are compromised by a stressor during pubertal development. Depending on the behavior, immune challenge or shipping from suppliers during pubertal development decreases, eliminates, or even reverses the effects of estradiol. Shipping during this period causes changes in the number of estrogen receptor-immunoreactive cells in key brain areas suggesting one cellular mechanism for this remodeling of the brain's response to hormones. We suggest that particular adverse experiences in girls may cause long-term alterations in the brain's response to estradiol and/or progesterone via activation of the immune system. This in turn could lead to an alteration in any aspect of mental health that is influenced by estradiol. PMID:26004504

  2. Hormone-regulated defense and stress response networks contribute to heterosis in Arabidopsis F1 hybrids

    PubMed Central

    Groszmann, Michael; Gonzalez-Bayon, Rebeca; Lyons, Rebecca L.; Greaves, Ian K.; Kazan, Kemal; Peacock, W. James; Dennis, Elizabeth S.

    2015-01-01

    Plant hybrids are extensively used in agriculture to deliver increases in yields, yet the molecular basis of their superior performance (heterosis) is not well understood. Our transcriptome analysis of a number of Arabidopsis F1 hybrids identified changes to defense and stress response gene expression consistent with a reduction in basal defense levels. Given the reported antagonism between plant immunity and growth, we suggest that these altered patterns of expression contribute to the greater growth of the hybrids. The altered patterns of expression in the hybrids indicate decreases to the salicylic acid (SA) biosynthesis pathway and increases in the auxin [indole-3-acetic acid (IAA)] biosynthesis pathway. SA and IAA are hormones known to control stress and defense responses as well as plant growth. We found that IAA-targeted gene activity is frequently increased in hybrids, correlating with a common heterotic phenotype of greater leaf cell numbers. Reduced SA concentration and target gene responses occur in the larger hybrids and promote increased leaf cell size. We demonstrated the importance of SA action to the hybrid phenotype by manipulating endogenous SA concentrations. Increasing SA diminished heterosis in SA-reduced hybrids, whereas decreasing SA promoted growth in some hybrids and phenocopied aspects of hybrid vigor in parental lines. Pseudomonas syringae infection of hybrids demonstrated that the reductions in basal defense gene activity in these hybrids does not necessarily compromise their ability to mount a defense response comparable to the parents. PMID:26527659

  3. Microarray Analysis of the Juvenile Hormone Response in Larval Integument of the Silkworm, Bombyx mori.

    PubMed

    Cheng, Daojun; Peng, Jian; Meng, Meng; Wei, Ling; Kang, Lixia; Qian, Wenliang; Xia, Qingyou

    2014-01-01

    Juvenile hormone (JH) coordinates with 20-hydroxyecdysone (20E) to regulate larval growth and molting in insects. However, little is known about how this cooperative control is achieved during larval stages. Here, we induced silkworm superlarvae by applying the JH analogue (JHA) methoprene and used a microarray approach to survey the mRNA expression changes in response to JHA in the silkworm integument. We found that JHA application significantly increased the expression levels of most genes involved in basic metabolic processes and protein processing and decreased the expression of genes associated with oxidative phosphorylation in the integument. Several key genes involved in the pathways of insulin/insulin-like growth factor signaling (IIS) and 20E signaling were also upregulated after JHA application. Taken together, we suggest that JH may mediate the nutrient-dependent IIS pathway by regulating various metabolic pathways and further modulate 20E signaling. PMID:24809046

  4. Microarray Analysis of the Juvenile Hormone Response in Larval Integument of the Silkworm, Bombyx mori

    PubMed Central

    Cheng, Daojun; Peng, Jian; Meng, Meng; Wei, Ling; Kang, Lixia; Qian, Wenliang; Xia, Qingyou

    2014-01-01

    Juvenile hormone (JH) coordinates with 20-hydroxyecdysone (20E) to regulate larval growth and molting in insects. However, little is known about how this cooperative control is achieved during larval stages. Here, we induced silkworm superlarvae by applying the JH analogue (JHA) methoprene and used a microarray approach to survey the mRNA expression changes in response to JHA in the silkworm integument. We found that JHA application significantly increased the expression levels of most genes involved in basic metabolic processes and protein processing and decreased the expression of genes associated with oxidative phosphorylation in the integument. Several key genes involved in the pathways of insulin/insulin-like growth factor signaling (IIS) and 20E signaling were also upregulated after JHA application. Taken together, we suggest that JH may mediate the nutrient-dependent IIS pathway by regulating various metabolic pathways and further modulate 20E signaling. PMID:24809046

  5. Generation of Islet-like Cell Aggregates from Human Adipose Tissue-derived Stem Cells by Lentiviral Overexpression of PDX-1

    PubMed Central

    Bahrebar, M.; Soleimani, M.; Karimi, M. H.; Vahdati, A.; Yaghobi, R.

    2015-01-01

    Background: Pancreatic duodenal homeobox1 (PDX-1) is a transcription factor that is important in regulating pancreas development and maintaining β-cell function. β-cell replacement is an effective approach for the treatment of type 1 diabetes. Human adipose-mesenchymal stem cells (hAMSCs) are the ideal population cells for differentiating into insulin-producing cells. Objective: To determine if islet-like cell aggregates production could be generated from hAMSCs by lentiviral overexpression of PDX-1. Methods: After isolation of hAMSCs, characteristics of these cells were identified by flow-cytometic analysis and multilineage differentiation studies. PDX-1 gene delivered into hAMSCs through lentiviral vector for differentiating hAMSCs into insulin-producing cells (IPCs) at the utilized protocol for 14 days. Characteristics of IPCs were evaluated by immunocytofluorescence, dithizone staining, and quantitative reverse transcription PCR. In response to high glucose medium, insulin release was detected by chemiluminescence enzyme immunoassay. Results: The islet-like cell aggregates appeared about 10 days after introduction of PDX-1 into hAMSCs. PDX-1 induced its own expression (auto-induction), a number of islet-related genes such as Ngn3, Nkx2-2, and insulin. The insulin-positive cells were detected in the PDX-1 transduced cells. In response to glucose challenge test, secretion of insulin hormone in the medium with high glucose concentration significantly increased in the PDX-1-transduced cells related to medium with low glucose concentration. Conclusion: Introduction of lentiviral PDX-1 significantly induces hAMSCs to differentiate into islet-like cell aggregates, which may provide a source of adipose stem cells-derived insulin-producing cells for cell replacement therapy in type 1 diabetes. PMID:26082830

  6. [Serum free thyroid hormones and response of TSH to TRH in nonthyroidal illnesses].

    PubMed

    Kokei, S; Inoue, T; Iino, S

    1986-11-20

    The change in the levels of free thyroid hormones and the pathophysiology of the hypothalamo-pituitary-thyroid axis of patients with nonthyroidal illness (NTI) have not been clearly elucidated so far. Therefore, it was thought of interest to investigate this problem by determining free thyroid hormones and TSH in serum and the response of TSH to TRH in these patients. The subjects employed in this study were 71 cases with hemodialysis, 40 cases with diabetes mellitus, 24 cases with liver cirrhosis, 12 cases with various cancers, 10 cases with anorexia nervosa and 110 normal subjects as controls. The serum total protein, albumin, free T4, free T3, TSH and other parameters of thyroid function were determined, and the TRH test was performed on about 10 patients of each group. Serum TSH was not only determined by a conventional assay system, but with a highly sensitive method, and the data were compared with one another. It was found that the serum free T3 levels were significantly low in all the groups investigated, but the serum free T4 levels were significantly low only in the groups with hemodialysis, decompensated liver cirrhosis, cancers and anorexia nervosa. No significant lowering of serum free T4 was observed in the patients with diabetes mellitus, acute hepatitis and compensated liver cirrhosis. However, serum TSH levels tended to be higher in all the groups studied, though they were not significant. The response of TSH to TRH was low or delayed in about 20-50% of patients with hemodialysis, diabetes mellitus, liver cirrhosis, cancers and anorexia nervosa. It was observed that the serum rT3 concentration was significantly high in the patients with diabetes mellitus and anorexia nervosa but significantly low in the patients on hemodialysis. In the rest of the groups, there were found many cases who showed high levels of serum rT3 although they were not statistically significant. These results indicate that low concentrations of serum free T3 observed in the

  7. Biphasic hormonal responses to the adrenocorticolytic DDT metabolite 3-methylsulfonyl-DDE in human cells

    SciTech Connect

    Asp, Vendela; Ulleras, Erik; Lindstroem, Veronica; Bergstroem, Ulrika; Oskarsson, Agneta; Brandt, Ingvar

    2010-02-01

    The DDT metabolite 3-methylsulfonyl-DDE (3-MeSO{sub 2}-DDE) has been proposed as a lead compound for an improved adrenocortical carcinoma (ACC) treatment. ACC is a rare malignant disorder with poor prognosis, and the current pharmacological therapy o,p'-DDD (mitotane) has limited efficacy and causes severe adverse effects. 3-MeSO{sub 2}-DDE is bioactivated by cytochrome P450 (CYP) 11B1 in mice and causes formation of irreversibly bound protein adducts, reduced glucocorticoid secretion, and cell death in the adrenal cortex of several animal species. The present study was carried out to assess similarities and differences between mice and humans concerning the adrenocorticolytic effects of 3-MeSO{sub 2}-DDE. The results support previous indications that humans are sensitive to the adrenocorticolytic actions of 3-MeSO{sub 2}-DDE by demonstrating protein adduct formation and cytotoxicity in the human adrenocortical cell line H295R. However, neither the irreversible binding nor the cytotoxicity of 3-MeSO{sub 2}-DDE in H295R cells was inhibited by the CYP11B1 inhibitor etomidate. We also report biphasic responses to 3-MeSO{sub 2}-DDE in cortisol and aldosterone secretion as well as in mRNA levels of the steroidogenic genes StAR, CYP11B1 and CYP11B2. Hormone levels and mRNA levels were increased at lower concentrations of 3-MeSO{sub 2}-DDE, while higher concentrations decreased hormone levels. These biphasic responses were not observed with o,p'-DDD or with the precursor DDT metabolite p,p'-DDE. Based on these results, 3-MeSO{sub 2}-DDE remains a viable lead compound for drug design, although the adrenocorticolytic effects of 3-MeSO{sub 2}-DDE in human cells seem more complex than in murine cells.

  8. Metabolic and hormonal responses during exercise at 20°, 0° and -20°C

    NASA Astrophysics Data System (ADS)

    Quirion, A.; Laurencelle, L.; Paulin, L.; Therminarias, A.; Brisson, G. R.; Audet, A.; Dulac, S.; Vogelaere, P.

    1989-12-01

    This study was designed to clarify the effects of cold air exposure on metabolic and hormonal responses during progressive incremental exercise. Eight healthy males volunteered for the study. Informed consent was obtained from every participant. The following protocol was administered to each subject on three occasions in a climatic chamber in which the temperature was 20°, 0° or -20°C with relative humidity at 60%±1%. Exercise tests were conducted on an electrically braked ergocycle, and consisted of a propressive incremental maximal exercise. Respiratory parameters were continuously monitored by an automated open-circuit sampling system Exercise blood lactate (LA), free fatty acids (FFA), glucose levels, bicarbonate concentration (HCO{3/-}), acidbase balance, plasma epinephrine (E) and norepinephrine (NE) were determined from venous blood samples obtained through an indwelling brachial catheter. Maximal oxygen uptake was significantly different between conditions: 72.0±5.4 ml kg-1 min-1 at 20°C; 68.9±5.1 ml kg-1 min-1 at 0°C and 68.5±4.6 ml kg-1 min-1 at -20°C. Workload, time to exhaustion, glucose levels and rectal Catecholamines and lactate values were not significantly altered by thermal conditions after maximal exercise but the catecholamines were decreased during rest. Bicarbonate, respiratory quotient, lactate and ventilatory thresholds increased significantly at -20°C. The data support the contention that metabolic and hormonal responses following progressive incremental exercise are altered by cold exposure and they indicate a marked decrease in maximal oxygen uptake, time to exhaustion and workload.

  9. Favorable Growth Hormone Treatment Response in a Young Boy with Achondroplasia

    PubMed Central

    Krstevska-Konstantinova, Marina; Stamatova, Ana; Gucev, Zoran

    2016-01-01

    Background: Achondroplasia is a skeletal dysplasia, the most common cause of rhizomelic dwarfism. Case presentation: This is a ten year old boy who was first diagnosed prenatally. He had a mutation c1138G>A in the gene FGFR3 in a heterozygotic constellation. His IGF1 and IGFBP3 levels were normal. Two stimulation tests for growth hormone were performed with values within the reference range. His psychomotor development was adequate for his age except for speech difficulty. He started with recombinant hGH (r-hGH) at the age of 3.4 years in a dose of 0.06 mg/kg. His mean Height SDS (HtSDS) was -2.2. Results: The growth increased to 10 cm/year in the first year of therapy (HtSDS -1.1). It decreased during the second year to 4 cm (HtSDS -1.7) and again increased during the third year to 8 cm/year (HtSDS–1.3). In the next years the growth was constant (6.5, 2.3, 3.5 cm / year). He is still growing in the 3rd percentile of the growth curve (HtSDS – 1.2) under GH treatment. The body disproportion remained the same. Conclusion: The growth response on GH treatment was satisfactory in the first 4 years of treatment, and the boy still continued to grow. The young age at the start of treatment was also of importance. Our other patients with achondroplasia who started treatment older had a poor response to growth hormone. PMID:27147792

  10. Growth control of prostatic carcinoma cells in serum-free media: interrelationship of hormone response, cell density, and nutrient media.

    PubMed Central

    Kaighn, M E; Kirk, D; Szalay, M; Lechner, J F

    1981-01-01

    Two established prostatic carcinoma cell lines have been grown in long-term culture in a defined medium (PFMR-4) free of serum, hormones, or growth factors. Growth of both lines in serum-free medium was population dependent. This cell-density requirement could be replaced by mitomycin C-inactivated feeder cells, homologous conditioned medium, or fetal bovine serum, but not by hormones or growth factors. The cells responded to these factors only at high density. The nature of this hormonal response was dependent on the kind of basal nutrient medium used. Growth in PFMR-4 with added insulin was more rapid than that in DME/F12 medium with any combination of hormones or growth factors and was substantially greater than growth in DME/F12 medium with insulin alone. The results demonstrate that whereas these two prostatic carcinoma lines (PC-3 and DU 145) do not require hormones for survival or growth, they do respond to certain hormones under appropriate conditions. These conditions include both the type of basal nutrient medium used and the population density. PMID:7029542

  11. Exendin-4 protects rat islets against loss of viability and function induced by brain death.

    PubMed

    Carlessi, Rodrigo; Lemos, Natália E; Dias, Ana L; Oliveira, Fernanda S; Brondani, Letícia A; Canani, Luis H; Bauer, Andrea C; Leitão, Cristiane B; Crispim, Daisy

    2015-09-01

    Islet quality loss after isolation from brain-dead donors still hinders the implementation of human islet transplantation for treatment of type 1 diabetes. In this scenario, systemic inflammation elicited by donor brain death (BD) is among the main factors influencing islet viability and functional impairment. Exendin-4 is largely recognized to promote anti-inflammatory and cytoprotective effects on β-cells. Therefore, we hypothesized that administration of exendin-4 to brain-dead donors might improve islet survival and insulin secretory capabilities. Here, using a rat model of BD, we demonstrate that exendin-4 administration to the brain-dead donors increases both islet viability and glucose-stimulated insulin secretion. In this model, exendin-4 treatment produced a significant decrease in interleukin-1β expression in the pancreas. Furthermore, exendin-4 treatment increased the expression of superoxide dismutase-2 and prevented BD-induced elevation in uncoupling protein-2 expression. Such observations were accompanied by a reduction in gene expression of two genes often associated with endoplasmic reticulum (ER) stress response in freshly isolated islets from treated animals, C/EBP homologous protein and immunoglobulin heavy-chain binding protein. As ER stress response has been shown to be triggered by and to participate in cytokine-induced β-cell death, we suggest that exendin-4 might exert its beneficial effects through alleviation of pancreatic inflammation and oxidative stress, which in turn could prevent islet ER stress and β-cell death. Our findings might unveil a novel strategy to preserve islet quality from brain-dead donors. After testing in the human pancreatic islet transplantation setting, this approach might sum to the ongoing effort to achieve consistent and successful single-donor islet transplantation. PMID:25976662

  12. Increased number of islet-associated macrophages in type 2 diabetes.

    PubMed

    Ehses, Jan A; Perren, Aurel; Eppler, Elisabeth; Ribaux, Pascale; Pospisilik, John A; Maor-Cahn, Ranit; Gueripel, Xavier; Ellingsgaard, Helga; Schneider, Marten K J; Biollaz, Gregoire; Fontana, Adriano; Reinecke, Manfred; Homo-Delarche, Francoise; Donath, Marc Y

    2007-09-01

    Activation of the innate immune system in obesity is a risk factor for the development of type 2 diabetes. The aim of the current study was to investigate the notion that increased numbers of macrophages exist in the islets of type 2 diabetes patients and that this may be explained by a dysregulation of islet-derived inflammatory factors. Increased islet-associated immune cells were observed in human type 2 diabetic patients, high-fat-fed C57BL/6J mice, the GK rat, and the db/db mouse. When cultured islets were exposed to a type 2 diabetic milieu or when islets were isolated from high-fat-fed mice, increased islet-derived inflammatory factors were produced and released, including interleukin (IL)-6, IL-8, chemokine KC, granulocyte colony-stimulating factor, and macrophage inflammatory protein 1alpha. The specificity of this response was investigated by direct comparison to nonislet pancreatic tissue and beta-cell lines and was not mimicked by the induction of islet cell death. Further, this inflammatory response was found to be biologically functional, as conditioned medium from human islets exposed to a type 2 diabetic milieu could induce increased migration of monocytes and neutrophils. This migration was blocked by IL-8 neutralization, and IL-8 was localized to the human pancreatic alpha-cell. Therefore, islet-derived inflammatory factors are regulated by a type 2 diabetic milieu and may contribute to the macrophage infiltration of pancreatic islets that we observe in type 2 diabetes. PMID:17579207

  13. Nmp4/CIZ suppresses the response of bone to anabolic parathyroid hormone by regulating both osteoblasts and osteoclasts

    PubMed Central

    Childress, Paul; Philip, Binu K.; Robling, Alexander G.; Bruzzaniti, Angela; Kacena, Melissa A.; Bivi, Nicoletta; Plotkin, Lilian I.; Heller, Aaron; Bidwell, Joseph P.

    2011-01-01

    How parathyroid hormone (PTH) increases bone mass is unclear but understanding this phenomenon is significant to the improvement of osteoporosis therapy. Nmp4/CIZ is a nucleocytoplasmic shuttling transcriptional repressor that suppresses PTH-induced osteoblast gene expression and hormone-stimulated gains in murine femoral trabecular bone. To further characterize Nmp4/CIZ suppression of hormone-mediated bone growth we treated 10 wk-old Nmp4-knockout (KO) and wild-type (WT) mice with intermittent human PTH (1-34) at 30μg/kg/day or vehicle, 7 days/wk, for 2, 3, or 7 wks. Null mice treated with hormone (7 wks) gained more vertebral and tibial cancellous bone than WT animals paralleling the exaggerated response in the femur. Interestingly, Nmp4/CIZ suppression of this hormone-stimulated bone formation was not apparent during the first 2 wks of treatment. Consistent with the null mice enhanced PTH-stimulated addition of trabecular bone these animals exhibited an augmented hormone-induced increase in serum osteocalcin 3 wks into treatment. Unexpectedly the Nmp4-KO mice displayed an osteoclast phenotype. Serum C-terminal telopeptides, a marker for bone resorption, was elevated in the null mice, irrespective of treatment. Nmp4-KO bone marrow cultures produced more osteoclasts, which exhibited an elevated resorbing activity, compared to WT cultures. The expression of several genes critical to the development of both osteoblasts and osteoclasts were elevated in Nmp4-KO mice at 2 wks but not 3 wks of hormone exposure. We propose that Nmp4/CIZ dampens PTH-induced improvement of trabecular bone throughout the skeleton by transiently suppressing hormone-stimulated increases in the expression of proteins key to the required enhanced activity/number of both osteoblasts and osteoclasts. PMID:21607813

  14. Nmp4/CIZ suppresses the response of bone to anabolic parathyroid hormone by regulating both osteoblasts and osteoclasts.

    PubMed

    Childress, Paul; Philip, Binu K; Robling, Alexander G; Bruzzaniti, Angela; Kacena, Melissa A; Bivi, Nicoletta; Plotkin, Lilian I; Heller, Aaron; Bidwell, Joseph P

    2011-07-01

    How parathyroid hormone (PTH) increases bone mass is unclear, but understanding this phenomenon is significant to the improvement of osteoporosis therapy. Nmp4/CIZ is a nucleocytoplasmic shuttling transcriptional repressor that suppresses PTH-induced osteoblast gene expression and hormone-stimulated gains in murine femoral trabecular bone. To further characterize Nmp4/CIZ suppression of hormone-mediated bone growth, we treated 10-week-old Nmp4-knockout (KO) and wild-type (WT) mice with intermittent human PTH(1-34) at 30 μg/kg daily or vehicle, 7 days/week, for 2, 3, or 7 weeks. Null mice treated with hormone (7 weeks) gained more vertebral and tibial cancellous bone than WT animals, paralleling the exaggerated response in the femur. Interestingly, Nmp4/CIZ suppression of this hormone-stimulated bone formation was not apparent during the first 2 weeks of treatment. Consistent with the null mice enhanced PTH-stimulated addition of trabecular bone, these animals exhibited an augmented hormone-induced increase in serum osteocalcin 3 weeks into treatment. Unexpectedly, the Nmp4-KO mice displayed an osteoclast phenotype. Serum C-terminal telopeptide, a marker for bone resorption, was elevated in the null mice, irrespective of treatment. Nmp4-KO bone marrow cultures produced more osteoclasts, which exhibited elevated resorbing activity, compared to WT cultures. The expression of several genes critical to the development of both osteoblasts and osteoclasts was elevated in Nmp4-KO mice at 2 weeks, but not 3 weeks, of hormone exposure. We propose that Nmp4/CIZ dampens PTH-induced improvement of trabecular bone throughout the skeleton by transiently suppressing hormone-stimulated increases in the expression of proteins key to the required enhanced activity and number of both osteoblasts and osteoclasts. PMID:21607813

  15. Detection of somatostatin receptors in surgical and percutaneous needle biopsy samples of carcinoids and islet cell carcinomas.

    PubMed

    Reubi, J C; Kvols, L K; Waser, B; Nagorney, D M; Heitz, P U; Charboneau, J W; Reading, C C; Moertel, C

    1990-09-15

    Somatostatin (SS) receptor status was investigated in the tumor tissues from 62 patients with carcinoid tumors and 15 patients with islet cell carcinomas using receptor autoradiography techniques with two different iodinated somatostatin analogues as radioligands, a [Leu8, DTrp22, Tyr25]somatostatin-28 and a somatostatin octapeptide, Tyr3-octreotide. The carcinoid tumors were either primaries (n = 32) or metastases (n = 43), sampled as surgical specimens or as small needle liver biopsies. Fifty-four of 62 carcinoid patients had SS receptor-positive tumors (87%). All 15 islet cell carcinoma patients had positive tumors (4 primaries, 11 metastases), i.e., 3 vipomas, 3 insulinomas, 2 glucagonomas, 1 gastrinoma, 2 polyfunctional tumors, and 4 nonfunctioning tumors. Saturation and competition experiments on tissue sections revealed saturable, high affinity binding sites pharmacologically specific for bioactive SS analogues. In a majority of the tumors, the receptors were densely distributed and were always homogeneously found in the whole tumor. All except two tumors were labeled with both radioligands. Multiple liver metastases (n = 16) from three different patients were all shown to contain a comparable amount of receptors. SS receptors could be demonstrated even in very small tissue samples of liver metastases obtained by percutaneous liver biopsies (mean weight, 6.8 mg). The majority of the eight SS receptor-negative carcinoids were mainly bronchial carcinoids (n = 5), usually poorly differentiated. On the contrary, SS receptor-positive cases were never found to be anaplastic. All tumors except one from patients pretreated with octreotide (3 days to 3.8 years) were SS receptor positive. In the majority of carcinoids or islet cell carcinomas, the SS receptor status correlated with the in vivo biochemical response (hormone inhibition) to octreotide. These data demonstrate (a) the high prevalence of SS receptors in the primary tumors of both carcinoids and islet cell

  16. Do early-life events permanently alter behavioral and hormonal responses to stressors?

    PubMed

    Anisman, H; Zaharia, M D; Meaney, M J; Merali, Z

    1998-01-01

    Early-life stimulation (e.g., brief handling) attenuates the behavioral and neuroendocrine responses to stressors encountered in adulthood, particularly with respect to activation of hypothalamic-pituitary-adrenal (HPA) activity. In contrast, if neonates were subjected to a more severe stressor, such as protracted separation from the dam or exposure to an endotoxin, then the adult response to a stressor was exaggerated. These early-life experiences program HPA functioning, including negative feedback derived from stimulation of hippocampal glucocorticoid receptors, and corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) coexpression in PVN neurons, to modify the response to subsequent stressor experiences. The persistent variations of HPA activity observed in handled/stimulated animals may stem from alterations in dam-pup interactions (e.g. increased arched-back feeding, licking, grooming). In addition genetic makeup is critical in determining stress reactivity. For instance, BALB/cByJ mice are more reactive to stressors than C57BL/6ByJ mice, exhibiting greater HPA hormonal alterations and behavioral disturbances. BALB/cByJ also fail to acquire a spatial learning response in a Morris water-maze paradigm, which has been shown to be correlated with hippocampal cell loss associated with aging. Early-life handling of BALB/cByJ mice prevented these performance deficits and attenuated the hypersecretion of ACTH and corticosterone elicited by stressors. The stressor reactivity may have been related to maternal and genetic factors. When BALB/cByJ mice were raised by a C57BL/6ByJ dam, the excessive stress-elicited HPA activity was reduced, as were the behavioral impairments. However, cross-fostering the more resilient C57BL/6ByJ mice to a BALB/cByJ dam failed to elicit the behavioral disturbances. It is suggested that genetic factors may influence dam-pup interactive styles and may thus proactively influence the response to subsequent stressors among

  17. Potentiation of Hormonal Responses to Hemorrhage and Fasting, but not Hypoglycemia in Conscious Adrenalectomized Rats

    NASA Technical Reports Server (NTRS)

    Darlington, Daniel N.; Keil, Lanny C.; Dallman, Mary F.

    1989-01-01

    Bilateral adrenalectomy (ADRX) in rats removes the source of two major stress-responsive hormones, corticosterone and epinephrine. To test how ADRX rats with-stand stress, we performed the following experiments in adult male rats provided with indwelling femoral arterial and venous cannulae and either ADRX or sham-adrenalectomized (Sham) 3 days later and given 0.5% NaCl to drink. Five to 6 days after adrenal surgery the rats were studied after either a 15 ml/kg.5 min hemorrhage or after an overnight fast followed by insulin-induced hypoglycemia. In fed unstressed ADRX rats, basal mean arterial blood pressure was slightly decreased; heart rate was increased; blood volume, vasopressin, and oxytocin concentrations were not different from sham values; and renin and norepinephrine were significantly elevated. The recovery of arterial pressure after hemorrhage in the ADRX rats was similar to that in the sham group over a 5-h period; however, the responses of vasopressin and oxytocin were significantly greater, and those of renin and norepinephrine were markedly potentiated in the ADRX group. Heart rate recovered faster in the ADRX group and was elevated, compared to the sham value, for most of the 5-h period. Restitution of blood volume was attenuated in the ADRX group, although the restitution of plasma protein was not different between the groups. A significant difference in the change in plasma osmolality between groups after hemorrhage may account for the attenuated restitution of blood volume. After an overnight fast, which reduced blood volume in both groups of rats, the plasma renin concentration rose still further in ADRX rats; the differences in other measured variables observed between fed ADRX and sham groups remained the same. The insulin-induced 50% decrease in glucose caused minor effects on arterial blood pressure and heart rate and occasioned responses in renin and norepinephrine of similar magnitudes in the two groups. We conclude that in the absence of

  18. Pancreas donation for islet transplantation.

    PubMed

    Frutos, M A; Ruiz, P; Mansilla, J J

    2005-04-01

    Islet transplantation, though still in the experimental phase, is a therapeutic option that has opened new expectations for the control of diabetes mellitus. Initial results are encouraging for the significant advantages compared with whole pancreas transplantation for selected patients with type 1 diabetes mellitus, with or without kidney failure. However, the success of transplantation, both at centers with more experience and others with less, is limited by the difficulty in obtaining a suitable number of donors and by laboratory isolation techniques. Significant advances require changes in donor selection, perfusion, oxygenation, and transfer of the pancreas, and in the process of isolation, purification, and culture in the laboratory. Of the 32 pancreases sent to the islet isolation laboratory from different hospitals in Andalusia, a viable percentage of islets was finally available in 19. However, in only 4 (18%) procedures were the preparations considered optimal for implantation in 2 recipients. PMID:15866673

  19. Signaling Responses to Pulsatile Gonadotropin-releasing Hormone in LβT2 Gonadotrope Cells*

    PubMed Central

    Tsutsumi, Rie; Mistry, Devendra; Webster, Nicholas J. G.

    2010-01-01

    The hypothalamic neuropeptide gonadotropin-releasing hormone (GnRH) is secreted in a pulsatile fashion by hypothalamic neurons, and alterations in pulse frequency and amplitude differentially regulate gonadotropin synthesis and release. In this study, we investigated the kinetics of Gs and Gq signaling in response to continuous or pulsatile GnRH using fluorescence resonance energy transfer reporters in live mouse LβT2 gonadotrope cells. cAMP and protein kinase A-dependent reporters showed a rapid but transient increase in fluorescence resonance energy transfer signal with increasing doses of constant GnRH, and in contrast diacylglycerol (DAG) and calcium reporters showed a rapid and sustained signal. Multiple pulses of GnRH caused multiple pulses of cAMP and protein kinase A activation without desensitization, but the DAG and calcium reporters were rapidly desensitized resulting in inhibition of calcium and DAG responses. At the transcriptional level, both a cAMP-dependent cAMP-response element reporter and a DAG/calcium-dependent AP-1 reporter showed a pulse frequency-dependent increase in luciferase activity. However, constant GnRH stimulation gave very little cAMP-response element activation but very strong AP-1 activation. Based on these data, we propose that both the GnRH-R-Gs and Gq pathways are responsive to pulses of GnRH, but only the Gq pathway is responsive to constant GnRH. Furthermore, the Gq pathway is subject to desensitization with multiple GnRH pulses, but the Gs pathway is not. PMID:20406815

  20. Brazilian Jiu-Jitsu Simulated Competition Part I: Metabolic, Hormonal, Cellular Damage, and Heart Rate Responses.

    PubMed

    Andreato, Leonardo V; Julio, Ursula F; Panissa, Valeria L G; Esteves, João V D C; Hardt, Felipe; de Moraes, Solange M F; de Souza, Camila O; Franchini, Emerson

    2015-09-01

    The aim of this study was to analyze physiological responses in Brazilian jiu-jitsu athletes during simulated competition. To this end, 10 athletes (age: 28 ± 4 years, body mass: 81.8 ± 7.4 kg, body fat: 13.0 ± 4.8%, systematic practice: 11 ± 4 years) were analyzed in simulated competition (4 matches of 10 minutes). Blood samples were taken to assess energy demand, hormonal responses, and cell damage. Additionally, the heart rate variability (HRV) response was analyzed. The main results show that in simulated competition, during the last matches, athletes had lower lactate (p < 0.001), epinephrine (p < 0.001), norepinephrine (p < 0.001), and insulin (p = 0.002) concentrations. Increases observed in creatine kinase (p < 0.001), aspartate aminotransferase (p < 0.001), alanine aminotransferase (p = 0.007), and creatinine (p < 0.001) seen, especially, in the last matches are indicative of possible cell damage. The HRV reflected a decrease in the RR medium (average of the normal R-R intervals) (p = 0.001) during the competition. Thus, it is concluded that successive matches from competition generate a gradual decrease of adrenergic and glycolytic activities, which is accompanied by a gradual increase in cell damage markers and decrease in the RR medium of the HRV. PMID:26308831

  1. Bidirectional promoters in seed development and related hormone/stress responses

    PubMed Central

    2013-01-01

    Background Bidirectional promoters are common in genomes but under-studied experimentally, particularly in plants. We describe a targeted identification and selection of a subset of putative bidirectional promoters to identify genes involved in seed development and to investigate possible coordinated responses of gene pairs to conditions important in seed maturation such as desiccation and ABA-regulation. Results We combined a search for 100–600 bp intergenic regions in the Arabidopsis genome with a cis-element based selection for those containing multiple copies of the G-box motif, CACGTG. One of the putative bidirectional promoters identified also contained a CE3 coupling element 5 bp downstream of one G-box and is identical to that characterized previously in the HVA1 promoter of barley. CE3 elements are significantly under-represented and under-studied in Arabidopsis. We further characterized the pair of genes associated with this promoter and uncovered roles for two small, previously uncharacterized, plant-specific proteins in Arabidopsis seed development and stress responses. Conclusions Using bioinformatics we identified putative bidirectional promoters involved in seed development and analysed expression patterns for a pair of plant-specific genes in various tissues and in response to hormones/stress. We also present preliminary functional analysis of these genes that is suggestive of roles in seed development. PMID:24261334

  2. Hormonal contraceptives suppress oxytocin-induced brain reward responses to the partner's face.

    PubMed

    Scheele, Dirk; Plota, Jessica; Stoffel-Wagner, Birgit; Maier, Wolfgang; Hurlemann, René

    2016-05-01

    The hypothalamic peptide oxytocin (OXT) has been identified as a key modulator of pair-bonding in men, but its effects in women are still elusive. Moreover, there is substantial evidence that hormonal contraception (HC) influences partner preferences and sexual satisfaction, which constitute core domains of OXT function. We thus hypothesized that OXT effects on partner-related behavioral and neural responses could be significantly altered in women using HC. In this functional magnetic resonance imaging study involving 40 pair-bonded women, 21 of whom were using HC, we investigated whether a 24-IU nasal dose of OXT would modulate brain reward responses evoked by the romantic partner's face relative to the faces of familiar and unfamiliar people. Treatment with OXT increased the perceived attractiveness of the partner relative to other men, which was paralleled by elevated responses in reward-associated regions, including the nucleus accumbens. These effects of OXT were absent in women using HC. Our results confirm and extend previous findings in men that OXT interacts with the brain reward system to reinforce partner value representations, indicating a common OXT-dependent mechanism underlying partner attraction in both sexes. This mechanism may be disturbed in women using HC, suggesting that gonadal steroids could alter partner-specific OXT effects. PMID:26722017

  3. The effect of combined hormonal contraceptives use on brain reactivity during response inhibition.

    PubMed

    Gingnell, Malin; Bannbers, Elin; Engman, Jonas; Frick, Andreas; Moby, Lena; Wikström, Johan; Sundström-Poromaa, Inger

    2016-04-01

    Objectives Cognitive control, which can be described as the ability to moderate impulses, has not previously been investigated in users of combined hormonal contraception (CHC). Given the suggested modulatory role of ovarian steroids in prefrontal dopaminergic function, which in turn taps into cognitive control, this randomised, double-blinded, placebo-controlled oral contraceptive trial set out to investigate the brain activity pattern during response inhibition in CHC users. Methods Thirty-four women were randomised to one treatment cycle with a levonorgestrel-containing CHC or placebo. The women performed a Go/NoGo task to measure brain activity during response inhibition by use of event-related functional magnetic resonance imaging (fMRI) prior to and during the CHC/placebo treatment cycle. Results No differences between CHC and placebo users in number of correct inhibitions were found during treatment, but only women on CHC significantly improved their performance between the baseline and treatment assessments. During the treatment cycle CHC users displayed decreased activity in the right middle frontal gyrus in comparison with placebo users. No other significant activations were evident between treatment groups or within groups. Conclusion Overall, CHC use had marginal effects on brain activity during response inhibition. If anything, the findings of the study may suggest reduced effort or increased efficiency in maintaining orbitofrontal cortex inhibitory cognitive control when using a combined oral contraceptive. PMID:26291330

  4. Ovarian and hormonal responses of cows to treatment with an analogue of gonadotrophin releasing hormone and prostaglandin F2 alpha.

    PubMed

    Peters, A R; Ward, S J; Warren, M J; Gordon, P J; Mann, G E; Webb, R

    1999-03-27

    Blood samples were taken from 11 cows and their ovaries were scanned by ultrasound at least daily. Around day 5 of an induced cycle, they were injected with 10 micrograms buserelin, an analogue of gonadotrophin releasing hormone, and on day 12 they received 0.5 mg cloprostenol, an analogue of prostaglandin F2 alpha (PGF2 alpha). Two days later six of the cows (the treated group) received a second injection of 10 micrograms buserelin, but the remaining five received no further treatment (control group). The dominant, that is, the largest follicle in each cow disappeared after the first buserelin injection and was replaced by a new one which grew synchronously in all the cows until after the treatment with PGF2 alpha. Ovulation occurred significantly earlier after PGF2 alpha in the treated group than in the control group (72 to 96 hours v 96 to 120 hours; P < 0.05). Plasma progesterone concentrations then increased more rapidly in the treated group than in the control group and were significantly higher on days 3 and 4 after ovulation (P < 0.05). PMID:10230012

  5. The search for the mechanism of early sympathetic islet neuropathy (eSIN) in autoimmune diabetes

    PubMed Central

    Taborsky, Gerald J.; Mei, Qi; Hackney, Daryl J.; Mundinger, Thomas O.

    2014-01-01

    This review outlines our search for the mechanism causing the early loss of islet sympathetic nerves in autoimmune diabetes. Since our previous work has documented the importance of autonomic stimulation of glucagon secretion during hypoglycaemia, the loss of these nerves may contribute to the known impairment of this specific glucagon response early in human type 1 diabetes. We therefore briefly review the contribution that autonomic activation, and sympathetic neural activation in particular, makes to the subsequent glucagon response to hypoglycaemia. We also detail evidence that animal models of autoimmune diabetes mimic both the early loss of islet sympathetic nerves and the impaired glucagon response seen in human type 1 diabetes. Using data from these animal models, we examine mechanisms by which this loss of islet nerves could occur. We provide evidence that it is not due to diabetic hyperglycaemia, but it is related to the lymphocytic infiltration of the islet. Ablating the p75 neurotrophin receptor, which is present on sympathetic axons, prevents eSIN, but, interestingly, not diabetes. Thus, we appear to have separated the immune-related loss of islet sympathetic nerves from the immune-mediated destruction of islet β-cells. Finally, we speculate on a way to restore the sympathetic innervation of the islet. PMID:25200302

  6. Co-transplantation of autologous MSCs delays islet allograft rejection and generates a local immunoprivileged site

    PubMed Central

    Ben Nasr, Moufida; Vergani, Andrea; Avruch, James; Liu, Liye; Kefaloyianni, Eirini; D’Addio, Francesca; Tezza, Sara; Corradi, Domenico; Bassi, Roberto; Valderrama-Vasquez, Alessandro; Usuelli, Vera; Kim, James; Azzi, Jamil; Essawy, Basset El; Markmann, James; Abdi, Reza

    2016-01-01

    Aims Mesenchymal stem cells (MSCs) are multipotent cells with immunomodulatory properties. We tested the ability of MSCs to delay islet allograft rejection. Methods Mesenchymal stem cells were generated in vitro from C57BL/6 and BALB/c mice bone marrow, and their immunomodulatory properties were tested in vitro. We then tested the effect of a local or systemic administration of heterologous and autologous MSCs on graft survival in a fully allogeneic model of islet transplantation (BALB/c islets into C57BL/6 mice). Results In vitro, autologous, but not heterologous, MSCs abrogated immune cell proliferation in response to alloantigens and skewed the immune response toward a Th2 profile. A single dose of autologous MSCs co-transplanted under the kidney capsule with allogeneic islets delayed islet rejection, reduced graft infiltration, and induced long-term graft function in 30 % of recipients. Based on ex vivo analysis of recipient splenocytes, the use of autologous MSCs did not appear to have any systemic effect on the immune response toward graft alloantigens. The systemic injection of autologous MSCs or the local injection of heterologous MSCs failed to delay islet graft rejection. Conclusion Autologous, but not heterologous, MSCs showed multiple immunoregulatory properties in vitro and delayed allograft rejection in vivo when co-transplanted with islets; however, they failed to prevent rejection when injected systemically. Autologous MSCs thus appear to produce a local immunoprivileged site, which promotes graft survival. PMID:25808641

  7. Bed rest suppresses bioassayable growth hormone release in response to muscle activity

    NASA Technical Reports Server (NTRS)

    McCall, G. E.; Goulet, C.; Grindeland, R. E.; Hodgson, J. A.; Bigbee, A. J.; Edgerton, V. R.

    1997-01-01

    Hormonal responses to muscle activity were studied in eight men before (-13 or -12 and -8 or -7 days), during (2 or 3, 8 or 9, and 13 or 14 days) and after (+2 or +3 and +10 or +11 days) 17 days of bed rest. Muscle activity consisted of a series of unilateral isometric plantar flexions, including 4 maximal voluntary contractions (MVCs), 48 contractions at 30% MVC, and 12 contractions at 80% MVC, all performed at a 4:1-s work-to-rest ratio. Blood was collected before and immediately after muscle activity to measure plasma growth hormone by radioimmunoassay (IGH) and by bioassay (BGH) of tibia epiphyseal cartilage growth in hypophysectomized rats. Plasma IGH was unchanged by muscle activity before, during, or after bed rest. Before bed rest, muscle activity increased (P < 0.05) BGH by 66% at -13 or -12 days (2,146 +/- 192 to 3,565 +/- 197 microg/l) and by 92% at -8 or -7 days (2,162 +/- 159 to 4,161 +/- 204 microg/l). After 2 or 3 days of bed rest, there was no response of BGH to the muscle activity, a pattern that persisted through 8 or 9 days of bed rest. However, after 13 or 14 days of bed rest, plasma concentration of BGH was significantly lower after than before muscle activity (2,594 +/- 211 to 2,085 +/- 109 microg/l). After completion of bed rest, muscle activity increased BGH by 31% at 2 or 3 days (1,807 +/- 117 to 2,379 +/- 473 microg/l; P < 0.05), and by 10 or 11 days the BGH response was similar to that before bed rest (1,881 +/- 75 to 4,160 +/- 315 microg/l; P < 0.05). These data demonstrate that the ambulatory state of an individual can have a major impact on the release of BGH, but not IGH, in response to a single bout of muscle activity.

  8. Thyroid hormone-regulated gene expression in juvenile mouse liver: identification of thyroid response elements using microarray profiling and in silico analyses

    PubMed Central

    2011-01-01

    Background Disruption of thyroid hormone signalling can alter growth, development and energy metabolism. Thyroid hormones exert their effects through interactions with thyroid receptors that directly bind thyroid response elements and can alter transcriptional activity of target genes. The effects of short-term thyroid hormone perturbation on hepatic mRNA transcription in juvenile mice were evaluated, with the goal of identifying genes containing active thyroid response elements. Thyroid hormone disruption was induced from postnatal day 12 to 15 by adding goitrogens to dams' drinking water (hypothyroid). A subgroup of thyroid hormone-disrupted pups received intraperitoneal injections of replacement thyroid hormones four hours prior to sacrifice (replacement). An additional group received only thyroid hormones four hours prior to sacrifice (hyperthyroid). Hepatic mRNA was extracted and hybridized to Agilent mouse microarrays. Results Transcriptional profiling enabled the identification of 28 genes that appeared to be under direct thyroid hormone-regulation. The regulatory regions of the genome adjacent to these genes were examined for half-site sequences that resemble known thyroid response elements. A bioinformatics search identified 33 thyroid response elements in the promoter regions of 13 different genes thought to be directly regulated by thyroid hormones. Thyroid response elements found in the promoter regions of Tor1a, 2310003H01Rik, Hect3d and Slc25a45 were further validated by confirming that the thyroid receptor is associated with these sequences in vivo and that it can bind directly to these sequences in vitro. Three different arrangements of thyroid response elements were identified. Some of these thyroid response elements were located far up-stream (> 7 kb) of the transcription start site of the regulated gene. Conclusions Transcriptional profiling of thyroid hormone disrupted animals coupled with a novel bioinformatics search revealed new thyroid

  9. In vitro maturation of viable islets from partially digested young pig pancreas.

    PubMed

    Lamb, Morgan; Laugenour, Kelly; Liang, Ouwen; Alexander, Michael; Foster, Clarence E; Lakey, Jonathan R T

    2014-03-01

    Isolation of islets from market-sized pigs is costly, with considerable islet losses from fragmentation occurring during isolation and tissue culture. Fetal and neonatal pigs yield insulin unresponsive islet-like cell clusters that become glucose-responsive after extended periods of time. Both issues impact clinical applicability and commercial scale-up. We have focused our efforts on a cost-effective scalable method of isolating viable insulin-responsive islets. Young Yorkshire pigs (mean age 20 days, range 4-30 days) underwent rapid pancreatectomy (<5 min) and partial digestion using low-dose collagenase, followed by in vitro culture at 37°C and 5% CO2 for up to 14 days. Islet viability was assessed using FDA/PI or Newport Green, and function was assessed using a glucose-stimulated insulin release (GSIR) assay. Islet yield was performed using enumeration of dithizone-stained aliquots. The young porcine (YP) islet yield at dissociation was 12.6 ± 2.1 × 10(3) IEQ (mean ± SEM) per organ and increased to 33.3 ± 6.4 × 10(3) IEQ after 7 days of in vitro culture. Viability was 97.3 ± 7% at dissociation and remained over 90% viable after 11 days in tissue culture (n = ns). Glucose responsiveness increased throughout maturation in culture. The stimulation index (SI) of the islets increased from 1.7 ± 2 on culture day 3 to 2.58 ± 0.5 on culture day 7. These results suggest that this method is both efficient and scalable for isolating and maturing insulin-responsive porcine islets in culture. PMID:23394130

  10. Effect of maternal stress on the stress hormone and growth response of pigs to a lipopolysaccharide (LPS) challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study assessed the effect of maternal stress on the stress hormone and growth response of the progeny following an endotoxin challenge. Sows were assigned to one of two treatments (n = 10 per treatment) and subjected to either a daily 5-min restraint stress (stressed; S) from d 84 to d 112 of g...

  11. Sexually dimorphic stress and innate immunological responses of Brahman cattle following an intravenous corticotropin-releasing hormone (CRH) challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to characterize potential sexually dimorphic stress and immunological responses following corticotrophin-releasing hormone (CRH) challenge. Six female (heifers) and five male (bulls) Brahman calves (264 ± 12 days of age) were challenged with 0.5 micrograms of CRH/kg body weig...

  12. Temporal pattern and effect of sex on lipopolysaccharide-induced stress hormone and cytokine response in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The temporal pattern and gender effect on immune and stress hormone responses to a lipopolysaccharide (LPS) challenge was assessed using a pig model. Secretion of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin-1 (IL-1) beta and IL-6 increased (P < 0.05) in a time-depend...

  13. Temporal pattern and effect of sex on lipopolysaccharide-induced stress hormone and cytokine response in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The temporal pattern and gender effect of immune and stress hormone responses to a lipopolysaccharide (LPS) challenge were assessed using a pig model. Secretion of the pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6 increased in a time-dependent manner f...

  14. Adenylate cyclase responsiveness to hormones in various portions of the human nephron.

    PubMed Central

    Chabardès, D; Gagnan-Brunette, M; Imbert-Teboul, M; Gontcharevskaia, O; Montégut, M; Clique, A; Morel, F

    1980-01-01

    The action sites for parathyroid hormone (PTH), salmon calcitonin (SCT), and arginine-vasopressin (AVP) were investigated along the human nephron by measuring adenylate cyclase activity, using a single tubule in vitro microassay. Well-localized segments of tubule were isolated by microdissection from five human kidneys unsuitable for transplantation. PTH (10 IU/ml) increased adenylate cyclase activity in the convoluted and the straight proximal tubule, in the medullary and cortical portions of the thick ascending limb, and in the early portion of the distal convoluted tubule (corresponding stimulated:basal activity ratios were 64, 19, 10, 18, and 22, respectively). SCT (10 ng/ml) increased adenylate cyclase activity in the medullary and cortical portions of the thick ascending limb, in the early portion of the distal convoluted tubule, and, to a lesser extent, in the cortical and the medullay collecting tubule (activity ratios were 7, 14, 15, 3, and 3, respectively). AVP (1 microM) stimulated adenylate cyclase activity in the terminal nephron segments only, i.e., the late portion of the distal convoluted tubule, the cortical and medullary portions of the collecting tubule (activity ratios 81, 51, and 97, respectively). As measured in one experiment, nearly one-half maximal responses were obtained with 0.1 IU/ml PTH or 0.3 ng/ml SCT in thick ascending limbs and with 1 nM AVP in collecting tubules, suggesting that enzyme sensitivity to hormones as well preserved under the conditions used in this study. PMID:7356689

  15. Regulation of hormonal responses of sweet pepper as affected by salinity and elevated CO2 concentration.

    PubMed

    Piñero, María Carmen; Houdusse, Fabrice; Garcia-Mina, Jose M; Garnica, María; Del Amor, Francisco M

    2014-08-01

    This study examines the extent to which the predicted CO2 -protective effects on the inhibition of growth, impairment of photosynthesis and nutrient imbalance caused by saline stress are mediated by an effective adaptation of the endogenous plant hormonal balance. Therefore, sweet pepper plants (Capsicum annuum, cv. Ciclón) were grown at ambient or elevated [CO2] (400 or 800 µmol mol(-1)) with a nutrient solution containing 0 or 80 mM NaCl. The results show that, under saline conditions, elevated [CO2] increased plant dry weight, leaf area, leaf relative water content and net photosynthesis compared with ambient [CO2], whilst the maximum potential quantum efficiency of photosystem II was not modified. In salt-stressed plants, elevated [CO2 ] increased leaf NO3(-) concentration and reduced Cl(-) concentration. Salinity stress induced ABA accumulation in the leaves but it was reduced in the roots at high [CO2], being correlated with the stomatal response. Under non-stressed conditions, IAA was dramatically reduced in the roots when high [CO2] was applied, which resulted in greater root DW and root respiration. Additionally, the observed high CK concentration in the roots (especially tZR) could prevent downregulation of photosynthesis at high [CO2], as the N level in the leaves was increased compared with the ambient [CO2], under salt-stress conditions. These results demonstrate that the hormonal balance was altered by the [CO2], which resulted in significant changes at the growth, gas exchange and nutritional levels. PMID:24152078

  16. Recovery from Disrupted Ultradian Glucocorticoid Rhythmicity Reveals a Dissociation Between Hormonal and Behavioural Stress Responsiveness

    PubMed Central

    Sarabdjitsingh, R.A.; Spiga, F.; Oitzl, M.S.; Kershaw, Y.; Meijer, O.C.; Lightman, S.L.; de Kloet, E.R.

    2016-01-01

    Ultradian release of glucocorticoids is thought to be essential for homeostasis and health. Furthermore, deviation from this pulsatile release pattern is considered to compromise resilience to stress-related disease, even after hormone levels have normalised. In the present study, we investigate how constant exposure to different concentrations of corticosterone affects diurnal and ultradian pulsatility. The rate of recovery in pulsatile hypothalamic-pituitary-adrenal (HPA) activity after withdrawal of exogenous corticosterone is also examined. Finally, the behavioural and neuroendocrine responsiveness to an audiogenic stressor is studied. Adrenally intact male rats were subcutaneously implanted with vehicle, 40% or 100% corticosterone pellets for 7 days. The continuous release of corticosterone from these implants abolished diurnal and ultradian corticosterone variation, as measured with high-frequency automated blood sampling. Pellet removal on post-surgery day 8 allowed rapid recovery of endogenous rhythms in animals previously exposed to daily average concentrations (40%) but not after exposure to high concentrations (100%) of corticosterone. Behavioural and neuroendocrine responsiveness to stress was distinctly different between the treatment groups. Audiogenic stimulation 1 day after pellet removal resulted in a similar corticosterone response in animals previously exposed to 40% corticosterone or vehicle. The 40% pellet group, however, showed less and shorter behavioural activity (i.e. locomotion, risk assessment) to noise stress compared to 100% corticosterone and vehicle-treated animals. In conclusion, unlike the animals impanted with 100% corticosterone, we find that basal HPA axis activity in the 40% group, which had mean daily levels of circulating corticosterone in the physiological range, rapidly reverts to the characteristic pulsatile pattern of corticosterone secretion. Upon reinstatement of the ultradian rhythm, and despite the fact that these

  17. Ovine corticotropin-releasing hormone stimulation test in patients with chronic renal failure: pharmacokinetic properties, and plasma adrenocorticotropic hormone and serum cortisol responses.

    PubMed

    Siamopoulos, K C; Eleftheriades, E G; Pappas, M; Sferopoulos, G; Tsolas, O

    1988-01-01

    The data on the status of the hypothalamic-pituitary-adrenal (HPA) axis in haemodialysis (HD) patients are conflicting. Moreover, a state reminiscent of Cushing's syndrome has been reported in this group of patients. Corticotropin-releasing hormone (CRH), that is produced by the hypothalamus and modulates the secretion of adrenocorticotropic hormone (ACTH), has been shown to be useful as a provocative test of the HPA axis. We investigated the effect of exogenous ovine CRH (oCRH) on plasma levels of ACTH and cortisol in 13 chronic HD patients. The plasma concentrations of immunoreactive CRH following oCRH administration were similar in patients and controls. In all patients, oCRH given intravenously as bolus injection caused a further increase in the already elevated levels of cortisol. The mean basal plasma levels of ACTH were within the normal range. There was, however, a blunted ACTH response to oCRH. We conclude that the HPA axis in chronic HD patients retains the ability to respond to exogenous oCRH. The patterns of the ACTH and cortisol response to this peptide resemble those observed in chronic stress (depression, anorexia nervosa). Besides, the kinetics of disappearance of oCRH indicate that the kidney may not be the major organ that metabolizes oCRH. PMID:2851525

  18. Isolation of Mouse Pancreatic Islets of Langerhans.

    PubMed

    Ramírez-Domínguez, Miriam

    2016-01-01

    The aim of any pancreatic islet isolation is obtaining pure, viable and functional pancreatic islets, either for in vitro or in vivo purposes. The islets of Langerhans are complex microorgans with the important role of regulating glucose homeostasis. Imbalances in glucose homeostasis lead to diabetes, which is defined by the American Diabetes Association as a "group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action or both" (American Diabetes Association 2011). Currently, the rising demand of human islets is provoking a shortage of this tissue, limiting research and clinical practice on this field. In this scenario, it is essential to investigate and improve islet isolation procedures in animal models, while keeping in mind the anatomical and functional differences between species. This chapter discusses the main aspects of mouse islet isolation research, highlighting the critical factors and shortcomings to take into account for the selection and/or optimization of a mouse islet isolation protocol. PMID:27586420

  19. In vitro reconstitution of pancreatic islets

    PubMed Central

    Kojima, Nobuhiko

    2014-01-01

    The lack of transplantable pancreatic islets is a serious problem that affects the treatment of patients with type 1 diabetes mellitus. Beta cells can be induced from various sources of stem or progenitor cells, including induced pluripotent stem cells in the near future; however, the reconstitution of islets from β cells in culture dishes is challenging. The generation of highly functional islets may require three-dimensional spherical cultures that resemble intact islets. This review discusses recent advances in the reconstitution of islets. Several factors affect the reconstitution of pseudoislets with higher functions, such as architectural similarity, cell-to-cell contact, and the production method. The actual transplantation of naked or encapsulated pseudoislets and islet-like cell clusters from various stem cell sources is also discussed. Advancing our understanding of the methods used to reconstitute pseudoislets should expand the range of potential strategies available for developing de novo islets for therapeutic applications. PMID:24589751

  20. Classification of microscopy images of Langerhans islets

    NASA Astrophysics Data System (ADS)

    Å vihlík, Jan; Kybic, Jan; Habart, David; Berková, Zuzana; Girman, Peter; Kříž, Jan; Zacharovová, Klára

    2014-03-01

    Evaluation of images of Langerhans islets is a crucial procedure for planning an islet transplantation, which is a promising diabetes treatment. This paper deals with segmentation of microscopy images of Langerhans islets and evaluation of islet parameters such as area, diameter, or volume (IE). For all the available images, the ground truth and the islet parameters were independently evaluated by four medical experts. We use a pixelwise linear classifier (perceptron algorithm) and SVM (support vector machine) for image segmentation. The volume is estimated based on circle or ellipse fitting to individual islets. The segmentations were compared with the corresponding ground truth. Quantitative islet parameters were also evaluated and compared with parameters given by medical experts. We can conclude that accuracy of the presented fully automatic algorithm is fully comparable with medical experts.

  1. High-Fat Diet-Induced Insulin Resistance Does Not Increase Plasma Anandamide Levels or Potentiate Anandamide Insulinotropic Effect in Isolated Canine Islets

    PubMed Central

    Woolcott, Orison O.; Richey, Joyce M.; Kabir, Morvarid; Chow, Robert H.; Iyer, Malini S.; Kirkman, Erlinda L.; Stefanovski, Darko; Lottati, Maya; Kim, Stella P.; Harrison, L. Nicole; Ionut, Viorica; Zheng, Dan; Hsu, Isabel R.; Catalano, Karyn J.; Chiu, Jenny D.; Bradshaw, Heather; Wu, Qiang; Bergman, Richard N.

    2015-01-01

    Background Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia. Objective To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets. Design and Methods Dogs were fed a high-fat diet (n = 9) for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7). Results Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, P<0.01). In vivo insulin sensitivity decreased by 31.3±12.1% (P<0.05), concomitant with a decrease in plasma 2-arachidonoyl glycerol (from 39.1±5.2 to 15.7±2.0 nmol/L) but not anandamide, oleoyl ethanolamide, linoleoyl ethanolamide, or palmitoyl ethanolamide. In control-diet animals (body weight: 28.8±1.0 kg), islets incubated with anandamide had a higher basal and glucose-stimulated insulin secretion as compared with no treatment. Islets from fat-fed animals (34.5±1.3 kg; P<0.05 versus control) did not exhibit further potentiation of anandamide-induced insulin secretion as compared with control-diet animals. Glucagon but not somatostatin secretion in vitro was also increased in response to anandamide, but there was no difference between groups (P = 0.705). No differences in gene expression of CB1R or CB2R between groups

  2. Estrogen receptor activation reduces lipid synthesis in pancreatic islets and prevents β cell failure in rodent models of type 2 diabetes

    PubMed Central

    Tiano, Joseph P.; Delghingaro-Augusto, Viviane; Le May, Cedric; Liu, Suhuan; Kaw, Meenakshi K.; Khuder, Saja S.; Latour, Martin G.; Bhatt, Surabhi A.; Korach, Kenneth S.; Najjar, Sonia M.; Prentki, Marc; Mauvais-Jarvis, Franck

    2011-01-01

    The failure of pancreatic β cells to adapt to an increasing demand for insulin is the major mechanism by which patients progress from insulin resistance to type 2 diabetes (T2D) and is thought to be related to dysfunctional lipid homeostasis within those cells. In multiple animal models of diabetes, females demonstrate relative protection from β cell failure. We previously found that the hormone 17β-estradiol (E2) in part mediates this benefit. Here, we show that treating male Zucker diabetic fatty (ZDF) rats with E2 suppressed synthesis and accumulation of fatty acids and glycerolipids in islets and protected against β cell failure. The antilipogenic actions of E2 were recapitulated by pharmacological activation of estrogen receptor α (ERα) or ERβ in a rat β cell line and in cultured ZDF rat, mouse, and human islets. Pancreas-specific null deletion of ERα in mice (PERα–/–) prevented reduction of lipid synthesis by E2 via a direct action in islets, and PERα–/– mice were predisposed to islet lipid accumulation and β cell dysfunction in response to feeding with a high-fat diet. ER activation inhibited β cell lipid synthesis by suppressing the expression (and activity) of fatty acid synthase via a nonclassical pathway dependent on activated Stat3. Accordingly, pancreas-specific deletion of Stat3 in mice curtailed ER-mediated suppression of lipid synthesis. These data suggest that extranuclear ERs may be promising therapeutic targets to prevent β cell failure in T2D. PMID:21747171

  3. Effects of hormone replacement therapy on hemodynamic responses of postmenopausal women to passive heating.

    PubMed

    Dunbar, S L; Kenney, W L

    2000-07-01

    To examine the influence of chronic hormone replacement therapy (HRT) on the central and peripheral cardiovascular responses of postmenopausal women to direct passive heating, seven women taking estrogen replacement therapy, seven women taking estrogen and progesterone therapy, and seven women not taking HRT were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), cardiac output, blood pressure, skin blood flow, splanchnic blood flow, renal blood flow, esophageal temperature, and mean skin temperature. Cardiac output was higher in women taking estrogen and progesterone therapy than in women not taking HRT (7.12 +/- 0.70 vs. 5.02 +/- 0. 57 l/min at the limit of thermal tolerance, respectively; P < 0.05) because of a higher HR. However, when the HR data were plotted as a percentage of the maximum HR or percentage of HR reserve, there were no differences among the three groups of women. Neither splanchnic nor renal blood flow differed among the groups of women. These data suggest that HRT has little effect on the cardiovascular responses to direct passive heating. PMID:10904040

  4. Ontogeny of lactoferrin in the developing mouse uterus: a marker of early hormone response.

    PubMed

    Newbold, R R; Hanson, R B; Jefferson, W N

    1997-05-01

    Lactoferrin (LF) was mapped during organogenesis of the murine reproductive tract, starting on fetal Day 12, as a marker of estrogen responsiveness. To induce LF expression, pregnant outbred CD-1 mice were injected s.c. with diethylstilbestrol (DES; 100 microg/kg maternal body weight), and fetal genital tract tissues were removed; neonatal and immature mice received s.c. injections of DES (2 microg/pup per day). Corn oil-treated and untreated mice at corresponding ages provided the controls. Immunocytochemical techniques using a polyclonal antibody showed no detectable LF in control genital tract tissues until late gestation. However, after DES treatment, LF was localized in uterine epithelial cells as early as fetal Day 14; the intensity of LF staining increased with age and number of DES treatments. Control uterine tissues responded to the rise of circulating estrogens at parturition (fetal Day 19) by producing LF, although the magnitude of response was lower than that of DES-treated tissues. Uterine tissue homogenates from control and DES mice were analyzed by SDS-PAGE and Western blots, verifying the protein to be LF. Isolation of mRNA and Northern blot analysis further showed that LF mRNA was present in the developing Mullerian duct and that DES stimulated early induction of the LF gene. The early appearance of LF suggests that it may play an important role in the hormonal regulation of growth and differentiation of developing uterine tissues. PMID:9160713

  5. Pathogenic Mechanisms in Type 1 Diabetes: The Islet is Both Target and Driver of Disease

    PubMed Central

    Graham, Kate L.; Sutherland, Robyn M.; Mannering, Stuart I.; Zhao, Yuxing; Chee, Jonathan; Krishnamurthy, Balasubramanian; Thomas, Helen E.; Lew, Andrew M.; Kay, Thomas W.H.

    2012-01-01

    Recent advances in our understanding of the pathogenesis of type 1 diabetes have occurred in all steps of the disease. This review outlines the pathogenic mechanisms utilized by the immune system to mediate destruction of the pancreatic beta-cells. The autoimmune response against beta-cells appears to begin in the pancreatic lymph node where T cells, which have escaped negative selection in the thymus, first meet beta-cell antigens presented by dendritic cells. Proinsulin is an important antigen in early diabetes. T cells migrate to the islets via the circulation and establish insulitis initially around the islets. T cells within insulitis are specific for islet antigens rather than bystanders. Pathogenic CD4+ T cells may recognize peptides from proinsulin which are produced locally within the islet. CD8+ T cells differentiate into effector T cells in islets and then kill beta-cells, primarily via the perforin-granzyme pathway. Cytokines do not appear to be important cytotoxic molecules in vivo. Maturation of the immune response within the islet is now understood to contribute to diabetes, and highlights the islet as both driver and target of the disease. The majority of our knowledge of these pathogenic processes is derived from the NOD mouse model, although some processes are mirrored in the human disease. However, more work is required to translate the data from the NOD mouse to our understanding of human diabetes pathogenesis. New technology, especially MHC tetramers and modern imaging, will enhance our understanding of the pathogenic mechanisms. PMID:23804258

  6. Adaptive Human CDKAL1 Variants Underlie Hormonal Response Variations at the Enteroinsular Axis

    PubMed Central

    Chang, Chia Lin; Cai, James J.; Huang, Shang Yu; Cheng, Po Jen; Chueh, Ho Yen; Hsu, Sheau Yu Teddy

    2014-01-01

    Recent analyses have identified positively selected loci that explain differences in immune responses, body forms, and adaptations to extreme climates, but variants that describe adaptations in energy-balance regulation remain underexplored. To identify variants that confer adaptations in energy-balance regulation, we explored the evolutionary history and functional associations of candidate variants in 207 genes. We screened single nucleotide polymorphisms in genes that had been associated with energy-balance regulation for unusual genetic patterns in human populations, followed by studying associations among selected variants and serum levels of GIP, insulin, and C-peptide in pregnant women after an oral glucose tolerance test. Our analysis indicated that 5′ variants in CDKAL1, CYB5R4, GAD2, and PPARG are marked with statistically significant signals of gene–environment interactions. Importantly, studies of serum hormone levels showed that variants in CDKAL1 are associated with glucose-induced GIP and insulin responses (p<0.05). On the other hand, a GAD2 variant exhibited a significant association with glucose-induced C-peptide response. In addition, simulation analysis indicated that a type 2 diabetes risk variant in CDKAL1 (rs7754840) was selected in East Asians ∼6,900 years ago. Taken together, these data indicated that variants in CDKAL1 and GAD2 were targets of prior environmental selection. Because the selection of the CDKAL1 variant overlapped with the selection of a cluster of GIP variants in the same population ∼11,800 to 2,000 years ago, we speculate that these regulatory genes at the human enteroinsular axis could be highly responsive to environmental selection in recent human history. PMID:25222615

  7. Altered regulation of energy homeostasis in older rats in response to thyroid hormone administration

    PubMed Central

    Walrand, Stephane; Short, Kevin R.; Heemstra, Lydia A.; Novak, Colleen M.; Levine, James A.; Coenen-Schimke, Jill M.; Nair, K. Sreekumaran

    2014-01-01

    Hyperthyroidism causes increased energy intake and expenditure, although anorexia and higher weight loss have been reported in elderly individuals with hyperthyroidism. To determine the effect of age on energy homeostasis in response to experimental hyperthyroidism, we administered 200 μg tri-iodothyronine (T3) in 7- and 27-mo-old rats for 14 d. T3 increased energy expenditure (EE) in both the young and the old rats, although the old rats lost more weight (147 g) than the young rats (58 g) because of the discordant effect of T3 on food intake, with a 40% increase in the young rats, but a 40% decrease in the old ones. The increased food intake in the young rats corresponded with a T3-mediated increase in the appetite-regulating proteins agouti-related peptide, neuropeptide Y, and uncoupling protein 2 in the hypothalamus, but no increase occurred in the old rats. Evidence of mitochondrial biogenesis in response to T3 was similar in the soleus muscle and heart of the young and old animals, but less consistent in old plantaris muscle and liver. Despite the comparable increase in EE, T3's effect on mitochondrial function was modulated by age in a tissue-specific manner. We conclude that older rats lack compensatory mechanisms to increase caloric intake in response to a T3-induced increase in EE, demonstrating a detrimental effect of age on energy homeostasis.—Walrand, S., Short, K. R., Heemstra, L. A., Novak, C. M., Levine, J. A., Coenen-Schimke, J. M., Nair, K. S. Altered regulation of energy homeostasis in older rats in response to thyroid hormone administration. PMID:24344330

  8. Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses

    PubMed Central

    Colborn, Theo; Hayes, Tyrone B.; Heindel, Jerrold J.; Jacobs, David R.; Lee, Duk-Hee; Shioda, Toshi; Soto, Ana M.; vom Saal, Frederick S.; Welshons, Wade V.; Zoeller, R. Thomas

    2012-01-01

    For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. PMID:22419778

  9. Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses.

    PubMed

    Vandenberg, Laura N; Colborn, Theo; Hayes, Tyrone B; Heindel, Jerrold J; Jacobs, David R; Lee, Duk-Hee; Shioda, Toshi; Soto, Ana M; vom Saal, Frederick S; Welshons, Wade V; Zoeller, R Thomas; Myers, John Peterson

    2012-06-01

    For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. PMID:22419778

  10. β-cell metabolic alterations under chronic nutrient overload in rat and human islets.

    PubMed

    Vernier, Stephanie; Chiu, Angela; Schober, Joseph; Weber, Theresa; Nguyen, Phuong; Luer, Mark; McPherson, Timothy; Wanda, Paul E; Marshall, Connie A; Rohatgi, Nidhi; McDaniel, Michael L; Greenberg, Andrew S; Kwon, Guim

    2012-01-01

    The aim of this study was to assess multifactorial β-cell responses to metabolic perturbations in primary rat and human islets. Treatment of dispersed rat islet cells with elevated glucose and free fatty acids (FFAs, oleate:palmitate = 1:1 v/v) resulted in increases in the size and the number of lipid droplets in β-cells in a time- and concentration-dependent manner. Glucose and FFAs synergistically stimulated the nutrient sensor mammalian target of rapamycin complex 1 (mTORC1). A potent mTORC1 inhibitor, rapamycin (25 nM), significantly reduced triglyceride accumulation in rat islets. Importantly, lipid droplets accumulated only in β-cells but not in α-cells in an mTORC1-dependent manner. Nutrient activation of mTORC1 upregulated the expression of adipose differentiation related protein (ADRP), known to stabilize lipid droplets. Rat islet size and new DNA synthesis also increased under nutrient overload. Insulin secretion into the culture medium increased steadily over a 4-day period without any significant difference between glucose (10 mM) alone and the combination of glucose (10 mM) and FFAs (240 μM). Insulin content and insulin biosynthesis, however, were significantly reduced under the combination of nutrients compared with glucose alone. Elevated nutrients also stimulated lipid droplet formation in human islets in an mTORC1-dependent manner. Unlike rat islets, however, human islets did not increase in size under nutrient overload despite a normal response to nutrients in releasing insulin. The different responses of islet cell growth under nutrient overload appear to impact insulin biosynthesis and storage differently in rat and human islets. PMID:23247575

  11. Influence of competition playing venue on the hormonal responses, state anxiety and perception of effort in elite basketball athletes.

    PubMed

    Arruda, Ademir F S; Aoki, Marcelo S; Freitas, Camila G; Drago, Gustavo; Oliveira, Roney; Crewther, Blair T; Moreira, Alexandre

    2014-05-10

    This study examined the influence of competition playing venue on the hormonal responses, state anxiety and perception of effort in elite basketball players. Eighteen males from two basketball teams were monitored during two competitive matches that were played against each other on a home and away basis. Salivary testosterone (T) and cortisol (C) concentrations were measured before and after each match. The Competitive State Anxiety Inventory-2 (CSAI-2) test was also administrated prior to each match and session ratings of perceived exertion (RPE) were taken post-game. Playing at home was accompanied by elevated pre-match T concentration, as compared to playing away (p<0.05). The matches played at home were also won. Salivary T and C concentrations were similarly elevated across the matches (percent changes from pre to post) played either at home or away. No significant differences in state anxiety and perception of effort were identified between the playing venues. Pre-match T and C concentrations and the percent changes in these hormones were significantly related to somatic anxiety, especially when playing at home (p<0.05). In conclusion, the competition playing venue appeared to influence athlete salivary hormonal responses prior to elite basketball matches. These hormonal responses were associated with player's anxiety state, which might contribute to performance and the eventual match outcomes. PMID:24642001

  12. Melatonin and Pancreatic Islets: Interrelationships between Melatonin, Insulin and Glucagon

    PubMed Central

    Peschke, Elmar; Bähr, Ina; Mühlbauer, Eckhard

    2013-01-01

    The pineal hormone melatonin exerts its influence in the periphery through activation of two specific trans-membrane receptors: MT1 and MT2. Both isoforms are expressed in the islet of Langerhans and are involved in the modulation of insulin secretion from β-cells and in glucagon secretion from α-cells. De-synchrony of receptor signaling may lead to the development of type 2 diabetes. This notion has recently been supported by genome-wide association studies identifying particularly the MT2 as a risk factor for this rapidly spreading metabolic disturbance. Since melatonin is secreted in a clearly diurnal fashion, it is safe to assume that it also has a diurnal impact on the blood-glucose-regulating function of the islet. This factor has hitherto been underestimated; the disruption of diurnal signaling within the islet may be one of the most important mechanisms leading to metabolic disturbances. The study of melatonin–insulin interactions in diabetic rat models has revealed an inverse relationship: an increase in melatonin levels leads to a down-regulation of insulin secretion and vice versa. Elucidation of the possible inverse interrelationship in man may open new avenues in the therapy of diabetes. PMID:23535335

  13. Lack of association of acute phase response proteins with hormone levels and antidepressant medication in perimenopausal depression

    PubMed Central

    2014-01-01

    Background Major depression is associated with higher plasma levels of positive acute-phase proteins, as well as with lower plasma levels of negative acute-phase proteins. The aim of this study is to examine the levels of acute-phase response proteins and whether these levels are influenced by reproductive hormones and antidepressant medication in the perimenopausal depression. Methods Sixty-five women (age range: 40–58 years old) participated in this study. All women were in the perimenopausal phase. The diagnosis of depression was made through a psychiatric interview and with the aid of Hamilton Depression Rating Scale 17 (HAM-D 17). The acute-phase response proteins, such as haptoglobin (HP), transferrine (TRf), α1-antitrypsin, complement protein 3 (C3), complement protein 4 (C4) and C-reactive protein (CRP) and the reproductive hormones, for example follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2), were analyzed using standard laboratory methods. Pearson’s correlations were applied to evaluate the relationship between acute-phase proteins and hormones. Results Perimenopausal women were divided into three groups. The first group consisted of normal controls, the second one involved depressed perimenopausal women, who were taking selective serotonin reuptake inhibitors (SSRIs), and the third one included depressed women that were not treated with SSRIs. Depressed women in perimenopause, when being compared to non-depressed women, did not differ as to serum levels of acute-phase proteins. There was a positive correlation between HP and E2 in depressed perimenopausal women, who were not taking SSRIs. Conclusions The lack of association between acute-phase proteins and depressive mood mentioned in this study does not support previous findings in patients with major depression. This negative finding in perimenopausal depression indicates either the absence or a more complex nature of the interactions between acute-phase proteins

  14. Parathyroid Hormone Responses to Catecholamines and to Changes of Extracellular Calcium in Cows

    PubMed Central

    Blum, Juerg W.; Fischer, Jan A.; Hunziker, Willi H.; Binswanger, U.; Picotti, Giovanni B.; Da Prada, Mosè; Guillebeau, Albin

    1978-01-01

    Modifications of the plasma level of immunoreactive parathyroid hormone (PTH) in cattle were induced by changes of the plasma concentrations of epinephrine, isoproterenol, or calcium. During abrupt hypocalcemia, PTH, obtained by infusions with ethylene glycol-bis (β-aminoethylether) N, N′-tetraacetate (EGTA), increased during the first 4-8 min. After a transient decline, the hormone levels rose again and remained elevated. Infusions of calcium suppressed the hypocalcemia-induced augmentation of PTH levels within a few minutes. Prolonged epinephrine (and isoproterenol) infusions also rapidly increased PTH levels, however, in this case, they returned to basal concentrations after 50-60 min. Additional epinephrine infusions could not further raise PTH values. Moreover, three short-lasting infusions of epinephrine (7 min each), given at 30-min intervals, increased PTH levels to the same extent, whereas additional infusions were much less effective. The PTH response to epinephrine was completely restored, when the interval after a prolonged epinephrine infusion had been prolonged to > 100 min. During moderate hypocalcemia, occurring at the end of EGTA infusions and lasting for 90 min, the PTH response to a short-lasting epinephrine infusion (7 min) was more pronounced than in normocalcemic animals. During severe hypocalcemia, in which superimposed short-lasting infusions of EGTA (7 min) led to an additional abrupt fall of plasma calcium concentrations but not to a corresponding additional rise of the PTH levels, epinephrine rapidly and further increased PTH concentrations. On the other hand, at the end of prolonged infusions of epinephrine, when additional infusions of epinephrine were ineffective in raising PTH levels, EGTA-induced hypocalcemia consistently increased PTH concentrations. The EGTA-induced augmentation of PTH levels was enhanced by epinephrine and isoproterenol but not by propranolol. The present findings indicate, that variations of the extracellular

  15. Microarray Analysis of Juvenile Hormone Response in Drosophila melanogaster S2 cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A microchip array encompassing probes for 14,010 genes of Drosophila melanogaster was used to analyze the effect of juvenile hormone (JH) on genome-wide gene expression. JH is a member of a key group of insect hormones involved in regulating larval development and adult reproductive processes. Altho...

  16. Mouse islet of Langerhans isolation using a combination of purified collagenase and neutral protease.

    PubMed

    Stull, Natalie D; Breite, Andrew; McCarthy, Robert; Tersey, Sarah A; Mirmira, Raghavendra G

    2012-01-01

    The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories(1-4), variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations(5, 6), but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh(7, 8), in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient(9), and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a(6) fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate(6). This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay(10). Utilizing these improved assays along with more

  17. Mouse Islet of Langerhans Isolation using a Combination of Purified Collagenase and Neutral Protease

    PubMed Central

    Stull, Natalie D.; Breite, Andrew; McCarthy, Robert; Tersey, Sarah A.; Mirmira, Raghavendra G.

    2012-01-01

    The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories1-4, variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations5, 6, but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh7, 8, in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient9, and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a6 fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate6. This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay10. Utilizing these improved assays along with more traditional

  18. Hormone levels

    MedlinePlus

    Blood or urine tests can determine the levels of various hormones in the body. This includes reproductive hormones, thyroid hormones, adrenal hormones, pituitary hormones, and many others. For more information, see: ...

  19. Role of imaging in clinical islet transplantation.

    PubMed

    Low, Gavin; Hussein, Nassrein; Owen, Richard J T; Toso, Christian; Patel, Vimal H; Bhargava, Ravi; Shapiro, A M James

    2010-03-01

    Islet transplantation is an innovative and effective clinical strategy for patients with type 1 diabetes whose clinical condition is inadequately managed even with the most aggressive medical treatment regimens. In islet transplantation, purified islets extracted from the pancreas of deceased donors are infused into the portal vein of the recipient liver. Engrafted islets produce insulin and thus restore euglycemia in many patients. After islet transplantation performed with the original Edmonton protocol, 80% of patients were insulin independent at 1 year and approximately 20% were insulin independent at 5 years. With more recent technical advances, 50% of patients or more maintain insulin independence 5 years after islet transplantation. The success rate with single-donor islet infusions has markedly improved over time. Even in patients who lose insulin independence, islet transplantation is considered successful because it provides improved glycemic control and a higher quality of life. Imaging plays an important role in islet transplantation and is routinely used to evaluate potential recipients, guide the transplantation process, and monitor patients for posttransplantation complications. Because of the success of islet transplantation and its increasing availability worldwide, familiarity with the role of imaging is important. PMID:20228322

  20. Differences between Human and Rodent Pancreatic Islets

    PubMed Central

    MacDonald, Michael J.; Longacre, Melissa J.; Stoker, Scott W.; Kendrick, Mindy; Thonpho, Ansaya; Brown, Laura J.; Hasan, Noaman M.; Jitrapakdee, Sarawut; Fukao, Toshiyuki; Hanson, Matthew S.; Fernandez, Luis A.; Odorico, Jon

    2011-01-01

    Anaplerosis, the net synthesis in mitochondria of citric acid cycle intermediates, and cataplerosis, their export to the cytosol, have been shown to be important for insulin secretion in rodent beta cells. However, human islets may be different. We observed that the enzyme activity, protein level, and relative mRNA level of the key anaplerotic enzyme pyruvate carboxylase (PC) were 80–90% lower in human pancreatic islets compared with islets of rats and mice and the rat insulinoma cell line INS-1 832/13. Activity and protein of ATP citrate lyase, which uses anaplerotic products in the cytosol, were 60–75% lower in human islets than in rodent islets or the cell line. In line with the lower PC, the percentage of glucose-derived pyruvate that entered mitochondrial metabolism via carboxylation in human islets was only 20–30% that in rat islets. This suggests human islets depend less on pyruvate carboxylation than rodent models that were used to establish the role of PC in insulin secretion. Human islets possessed high levels of succinyl-CoA:3-ketoacid-CoA transferase, an enzyme that forms acetoacetate in the mitochondria, and acetoacetyl-CoA synthetase, which uses acetoacetate to form acyl-CoAs in the cytosol. Glucose-stimulated human islets released insulin similarly to rat islets but formed much more acetoacetate. β-Hydroxybutyrate augmented insulin secretion in human islets. This information supports previous data that indicate beta cells can use a pathway involving succinyl-CoA:3-ketoacid-CoA transferase and acetoacetyl-CoA synthetase to synthesize and use acetoacetate and suggests human islets may use this pathway more than PC and citrate to form cytosolic acyl-CoAs. PMID:21454710

  1. Mink aging is associated with a reduction in ovarian hormone release and the response to FSH and ghrelin.

    PubMed

    Sirotkin, Alexander V; Mertin, Dušan; Süvegová, Karina; Lauričik, Jozef; Morovič, Martin; Harrath, Abdel Halim; Kotwica, Jan

    2016-09-15

    The endocrine mechanisms of mink ovarian hormones release and reproductive aging are poorly investigated. The aims of our study were to: (1) identify hormones produced by mink ovaries (the steroids progesterone [P] and estradiol [E], the peptide hormone oxytocin [OT], and the prostaglandin F [PGF] and prostaglandin E [PGE]); (2) examine the effect of FSH and ghrelin on the release of the hormones listed previously; and (3) understand whether these hormones can be involved in the control of mink reproductive aging, i.e., whether aging can be associated with changes (a) in the basal release of P, E, OT, PGF, or PGE and (b) their response to FSH and ghrelin. Fragments of ovaries of young (yearlings) and old (3-5 years of age) minks were cultured with and without FSH and ghrelin (0, 1, 10, or 100 ng/mL), and the release of hormones was analyzed by EIA/RIA. We found that isolated ovaries were able to release P, E, OT, PGF, and PGE, and the levels of P produced in the ovaries of old animals were lower than those produced in the ovaries of young animals, whereas the levels of other hormones did not differ. FSH was able to stimulate P and E and suppress OT and PGF and did not affect PGE release. Aging was associated with the inhibition of the effect of FSH on ovarian P and E, the appearance of the inhibitory action of FSH on OT, and the disappearance of this action on ovarian PGF. PGE was not affected by FSH, irrespective of animal age. Ghrelin was able to promote E (but not P) and suppress OT, PGF, and PGE output. Aging was associated with the appearance of an inhibitory influence of ghrelin on ovarian OT and PGE and with the disappearance of this influence on PGF output. Aging did not affect the action of ghrelin on ovarian P and E. Our observations (1) confirm the production of P and E and show that OT, PGF, and PGE are released from mink ovaries, (2) confirm the involvement of FSH and demonstrate the involvement of ghrelin in the control of mink ovarian hormone

  2. Hormonal response of male green anole lizards (Anolis carolinensis) to GnRH challenge.

    PubMed

    Husak, Jerry F; Irschick, Duncan J; Henningsen, Justin P; Kirkbride, Kimberly S; Lailvaux, Simon P; Moore, Ignacio T

    2009-02-01

    Circulating plasma levels of testosterone often differ among social classes of sexually mature males within a population, but the general physiological mechanisms underlying such differences remain unclear. Within sexually mature male green anole lizards (Anolis carolinensis), smaller "lightweight" males have on average relatively smaller heads, lower bite-forces, and lower testosterone levels compared with larger "heavyweight" males. We conducted gonadotropin-releasing hormone (GnRH) challenges on lightweight and heavyweight males to determine if lightweight males were capable of producing comparable levels of circulating testosterone to heavyweight males but are socially or physiologically suppressed from doing so. We challenged lightweight and heavyweight males with chicken I and II GnRH and measured their resulting levels of testosterone and corticosterone. Neither lightweights nor heavyweights increased circulating testosterone levels after GnRH challenge, suggesting they are already at maximal production levels, consistent with the Challenge Hypothesis. Instead, testosterone levels tended to decrease and corticosterone levels increased, most likely owing to the stress response associated with handling. Our results are dramatically different from GnRH challenges conducted in bird species, suggesting that more field studies are needed in reptilian systems. PMID:19012286

  3. Active vs. passive recovery during high-intensity training influences hormonal response.

    PubMed

    Wahl, P; Mathes, S; Achtzehn, S; Bloch, W; Mester, J

    2014-06-01

    The aim of the present study was to compare the effects of active (A) vs. passive (P) recovery during high-intensity interval training on the acute hormonal and metabolic response. Twelve triathletes/cyclists performed four 4 min intervals on a cycle ergometer, either with A- or P-recovery between each bout. Testosterone, hGH, cortisol, VEGF, HGF and MIF were determined pre, 0', 30', 60' and 180' after both interventions. Metabolic perturbations were characterized by lactate, blood gas and spirometric analysis. A-recovery caused significant increases in circulating levels of cortisol, testosterone, T/C ratio, hGH, VEGF and HGF. Transient higher levels were found for cortisol, testosterone, hGH, VEGF, HGF and MIF after A-recovery compared to P-recovery, despite no differences in metabolic perturbations. A-recovery was more demanding from an athlete's point of view. Based on the data of testosterone, hGH and the T/C-ratio, as well as on the data of VEGF and HGF it appears that this kind of exercise protocol with A-recovery phases between the intervals may promote anabolic processes and may lead to pro-angiogenic conditions more than with P-recovery. These data support the findings that also the long term effects of both recovery modes seem to differ, and that both can induce specific adaptations. PMID:24258473

  4. Mediators of the biphasic responses of bone to intermittent and continuously administered parathyroid hormone.

    PubMed

    Locklin, Rachel M; Khosla, Sundeep; Turner, Russell T; Riggs, B Lawrence

    2003-05-01

    Parathyroid hormone (PTH) has biphasic effects on bone: continuous treatment is catabolic whereas intermittent treatment is anabolic. The mechanism(s) responsible for these differing effects are still unclear, partly because of the previous non-availability of a model system in which effects on both formation and resorption indices could be studied concomitantly. In cultured marrow cells from 6-week old C57BL/6 mice, we demonstrated that 4 days of intermittent PTH treatment increased mRNA for osteoblast differentiation markers (Runx2, alkaline phosphatase (AP), and type I procollagen (COL1A1) whereas continuous treatment resulted in production of large numbers of TRAP-positive multinucleated osteoclasts. Although IGF-I mRNA did not increase after intermittent treatment, it was consistently higher than after continuous treatment, and the addition of an anti-IGF-I neutralizing antibody prevented the increase in bone formation indices observed with intermittent treatment. By contrast, after continuous treatment, gene expression of RANK ligand (RANKL) was increased and that of osteoprotegerin (OPG) was decreased, resulting in a 25-fold increase in the RANKL/OPG ratio. In this model system, the data suggest that intermittent PTH treatment enhances osteoblast differentiation through an IGF-I dependent mechanism and continuous PTH treatment enhances osteoclastogenesis through reciprocal increases in RANKL and decreases in OPG. PMID:12682918

  5. Effects of age and sex on hormonal responses to weightlessness simulation

    NASA Technical Reports Server (NTRS)

    Larochelle, F.; Leach, C.; Vernikos-Danellis, J.

    1982-01-01

    The effects of horizontal bedrest on the excretion of catecholamines, aldosterone, and cortisol by human subjects grouped by age and sex are examined. The responses are assessed by assays of 24-hr urine samples collected throughout the studies. In 36-45-yr-olds, the excretion of epinephrine increases, whereas it decreases in the 46-55- and 56-65-yr-old groups. Norepinephrine excretion decreases (5-27%) in all groups during bedrest. Aldosterone excretion increases in the younger two groups of both males (19 and 6%) and females (47 and 9%). A slight decrease is observed in 56-65-yr-old males (6%), whereas excretion in females is unchanged. Cortisol excretion increases in the youngest groups of both men (12%) and women (13%) but decreases in the 56-65-yr-old groups (6 and 5%). For the two groups of intermediate age (46-55 yr), excretion in females decreases (15%), whereas in males it increases (19%). It is believed that hormone measurements may be of value in explaining variation in stress tolerance due to age and/or sex during space flight.

  6. FRET-based voltage probes for confocal imaging: membrane potential oscillations throughout pancreatic islets.

    PubMed

    Kuznetsov, Andrey; Bindokas, Vytautas P; Marks, Jeremy D; Philipson, Louis H

    2005-07-01

    Insulin secretion is dependent on coordinated pancreatic islet physiology. In the present study, we found a way to overcome the limitations of cellular electrophysiology to optically determine cell membrane potential (V(m)) throughout an islet by using a fast voltage optical dye pair. Using laser scanning confocal microscopy (LSCM), we observed fluorescence (Förster) resonance energy transfer (FRET) with the fluorescent donor N-(6-chloro-7-hydroxycoumarin-3-carbonyl)-dimyristoylphosphatidyl-ethanolamine and the acceptor bis-(1,3-diethylthiobarbiturate) trimethine oxonol in the plasma membrane of essentially every cell within an islet. The FRET signal was approximately linear from V(m) -70 to +50 mV with a 2.5-fold change in amplitude. We evaluated the responses of islet cells to glucose and tetraethylammonium. Essentially, every responding cell in a mouse islet displayed similar time-dependent changes in V(m). When V(m) was measured simultaneously with intracellular Ca2+, all active cells showed tight coupling of V(m) to islet cell Ca2+ changes. Our findings indicate that FRET-based, voltage-sensitive dyes used in conjunction with LSCM imaging could be extremely useful in studies of excitation-secretion coupling in intact islets of Langerhans. PMID:15758044

  7. Histopathology and ex vivo insulin secretion of pancreatic islets in gestational diabetes: A case report.

    PubMed

    Tancredi, Mariella; Marselli, Lorella; Lencioni, Cristina; Masini, Matilde; Bugliani, Marco; Suleiman, Mara; Masiello, Pellegrino; Boggi, Ugo; Filipponi, Franco; Dotta, Francesco; Marchetti, Piero; Di Cianni, Graziano

    2011-01-01

    Gestational diabetes (GD) results from insufficient endogenous insulin supply. No information is available on features of islet cells in human GD. Herein, we describe several properties of islets from a woman with GD. Immunohistochemical stainings and EM analyses were performed on pancreatic samples. Islet isolation was achieved by enzymatic dissociation and density gradient centrifugation. Ex vivo insulin secretion was studied in response to fuel secretagogues. Control islets were obtained from matched non-pregnant, non-diabetic women. Total insulin positive area was lower in GD, mainly due to the presence of smaller islets. β-cell apoptosis and the presence of Ki67 positive islet cells were similar in GD and controls, whereas the amount of insulin positive cells in or close to the ducts was decreased in GD. Ex vivo insulin secretion did not differ between GD and non-pregnant, non-diabetic islets. These findings suggest that in this case of human GD there might mainly be a defect of β-cell amount, not due to increased apoptosis, but possibly to insufficient regeneration. PMID:21765242

  8. Reproductive Hormone and Transcriptomic Responses of Pituitary Tissue in Anestrus Gilts Induced by Nutrient Restriction

    PubMed Central

    Xu, Shengyu; Wang, Dingyue; Zhou, Dongsheng; Lin, Yan; Che, Lianqiang; Fang, Zhengfeng; Wu, De

    2015-01-01

    The onset of estrus is a critical sign of female sexual maturity. The pituitary plays a vital role in this process by the secretion of reproductive hormones. To investigate the effects of nutrient restriction on reproductive function and the underlying mechanisms involved, deep RNA sequencing of pituitary gland tissue was carried out to determine the differentially expressed genes (DEGs) between gilts in normal estrus, and gilts in which anestrus was induced by nutrient restriction. Gilts which had gone through two estrus cycles were fed a normal (CON, 2.86kg/d, n = 10) or nutrient restricted (NR, 1kg/d, n = 10) diet. The NR gilts experienced another three estrus cycles, but did not express estrus symptoms at the anticipated 6th and 7th cycles. Body weight gain in NR gilts was significantly decreased by nutrient restriction. Gilts were considered as anestrus when blood progesterone concentrations lower than 1.0 ng/mL from three consecutive blood samples were recorded. Circulating concentrations of progesterone (< 1.0 ng/mL vs. 2.1 ng/mL) and estradiol (208.6 ng/mL vs. 371.8 ng/mL) were significantly lower in the NR gilts than in the CON gilts. Between 5,360,000 and 5,370,000 sequence reads per sample from the CON and NR gilts’ pituitaries were obtained and mapped to the porcine genome. Analysis of read counts revealed 185 DEGs. Expression of selected genes was validated by the use of quantitative real-time RT-PCR. Bioinformatic analysis identified that the genes identified were enriched in the GO terms “neuroactive ligand-receptor interaction”, “GnRH signaling pathway” and “immune response system”. Our findings provide a new perspective for understanding the nutrient restriction-induced reproductive impairment at the pituitary transcriptional level, and how this is linked to hormone secretion. Moreover, the transcriptomic changes in anestrus gilts associated with nutrient restriction could be a resource for targeted studies of genes and pathways

  9. Lipolysis in diabetic adipocytes: differences in response to growth hormone and adenosine.

    PubMed

    Solomon, S S; Schwartz, Y; Rawlinson, T

    1987-09-01

    The sensitivity to lipolytic agents is altered in diabetic vs. control animals. Because of its role as a diabetogenic hormone and its ability to elicit lipolysis, GH was studied in isolated fat cells (IFC) from control and streptozotocin-diabetic (STZ-DM) rats. IFCs from the epididymal fat of 150 to 200-g normal and STZ-DM Holtzman rats were prepared by collagenase digestion. Lipolysis was measured by glycerol release after either incubation or perifusion with the following concentrations: epinephrine (EPI), 0.01-0.1 microM; theophylline, 0.01-1.0 mg/ml; adenosine deaminase (ADA), and bovine GH (bGH), 0.01-1.0 microgram/ml. Rats, rendered diabetic by STZ (65 mg/kg), were used on day 3. In a dose-response study comparing glycerol release from control and STZ-DM IFC, IFC were preincubated with 1.0 microgram/ml bGH and then incubated with varying concentrations of EPI or bGH. In STZ-DM, we noted increased lipolytic sensitivity to low concentrations of EPI or bGH. Furthermore, in perifusion, STZ-DM IFC did not require obligatory preincubation with bGH for optimal glycerol release. The addition of ADA increased glycerol release from incubated IFC (STZ-DM and controls). In both systems an enhanced lipolytic response to theophylline was seen in the presence of bGH in control and STZ-DM. It was thus concluded that IFC from normal animals do not respond to GH without preincubation. IFC from STZ-DM rats show a lipolytic response to GH without preincubation. Preincubation with GH increases the lipolytic response of IFC from STZ-DM to all lipolytic agents compared to control responses. In addition, ADA greatly enhanced lipolysis in IFC from STZ-DM compared to that in controls. Together these data demonstrate enhanced sensitivity to both lipolytic stimuli and adenosine suppression of lipolysis in IFC from STZ-DM. PMID:3622374

  10. Islet adaptation to obesity and insulin resistance in WNIN/GR-Ob rats

    PubMed Central

    Singh, Himadri; Ganneru, Sireesha; Malakapalli, Venkata; Chalasani, Maniprabha; Nappanveettil, Giridharan; Bhonde, Ramesh R; Venkatesan, Vijayalakshmi

    2014-01-01

    WNIN/GR-Ob mutant rat is a novel animal model to study metabolic syndrome (obesity, insulin resistance, hyperinsulinemia, impaired glucose tolerance and cardiovascular diseases). We have investigated the islet characteristics of obese mutants at different age groups (1, 6 and 12 months) to assess the islet changes in response to early and chronic metabolic stress. Our data demonstrates altered islet cell morphology and function (hypertrophy, fibrotic lesions, vacuolation, decreased stimulation index, increased TNFα, ROS and TBARS levels) in mutants as compared to controls. Furthermore, network analysis (gene-gene interaction) studied in pancreas demonstrated increased inflammation as a key factor underlying obesity/metabolic syndrome in mutants. These observations pave way to explore this model to understand islet adaptation in response to metabolic syndrome. PMID:25833252

  11. Fetal and neonatal iron deficiency exacerbates mild thyroid hormone insufficiency effects on male thyroid hormone levels and brain thyroid hormone-responsive gene expression.

    PubMed

    Bastian, Thomas W; Prohaska, Joseph R; Georgieff, Michael K; Anderson, Grant W

    2014-03-01

    Fetal/neonatal iron (Fe) and iodine/TH deficiencies lead to similar brain developmental abnormalities and often coexist in developing countries. We recently demonstrated that fetal/neonatal Fe deficiency results in a mild neonatal thyroidal impairment, suggesting that TH insufficiency contributes to the neurodevelopmental abnormalities associated with Fe deficiency. We hypothesized that combining Fe deficiency with an additional mild thyroidal perturbation (6-propyl-2-thiouracil [PTU]) during development would more severely impair neonatal thyroidal status and brain TH-responsive gene expression than either deficiency alone. Early gestation pregnant rats were assigned to 7 different treatment groups: control, Fe deficient (FeD), mild TH deficient (1 ppm PTU), moderate TH deficient (3 ppm PTU), severe TH deficient (10 ppm PTU), FeD/1 ppm PTU, or FeD/3 ppm PTU. FeD or 1 ppm PTU treatment alone reduced postnatal day 15 serum total T4 concentrations by 64% and 74%, respectively, without significantly altering serum total T3 concentrations. Neither treatment alone significantly altered postnatal day 16 cortical or hippocampal T3 concentrations. FeD combined with 1 ppm PTU treatment produced a more severe effect, reducing serum total T4 by 95%, and lowering hippocampal and cortical T3 concentrations by 24% and 31%, respectively. Combined FeD/PTU had a more severe effect on brain TH-responsive gene expression than either treatment alone, significantly altering Pvalb, Dio2, Mbp, and Hairless hippocampal and/or cortical mRNA levels. FeD/PTU treatment more severely impacted cortical and hippocampal parvalbumin protein expression compared with either individual treatment. These data suggest that combining 2 mild thyroidal insults during development significantly disrupts thyroid function and impairs TH-regulated brain gene expression. PMID:24424046

  12. Salivary hormone and immune responses to three resistance exercise schemes in elite female athletes.

    PubMed

    Nunes, João A; Crewther, Blair T; Ugrinowitsch, Carlos; Tricoli, Valmor; Viveiros, Luís; de Rose, Dante; Aoki, Marcelo S

    2011-08-01

    This study examined the salivary hormone and immune responses of elite female athletes to 3 different resistance exercise schemes. Fourteen female basketball players each performed an endurance scheme (ES-4 sets of 12 reps, 60% of 1 repetition maximum (1RM) load, 1-minute rest periods), a strength-hypertrophy scheme (SHS-1 set of 5RM, 1 set of 4RM, 1 set of 3RM, 1 set of 2RM, and 1set of 1RM with 3-minute rest periods, followed by 3 sets of 10RM with 2-minute rest periods) and a power scheme (PS-3 sets of 10 reps, 50% 1RM load, 3-minute rest periods) using the same exercises (bench press, squat, and biceps curl). Saliva samples were collected at 07:30 hours, pre-exercise (Pre) at 09:30 hours, postexercise (Post), and at 17:30 hours. Matching samples were also taken on a nonexercising control day. The samples were analyzed for testosterone, cortisol (C), and immunoglobulin A concentrations. The total volume of load lifted differed among the 3 schemes (SHS > ES > PS, p < 0.05). Postexercise C concentrations increased after all schemes, compared to control values (p < 0.05). In the SHS, the postexercise C response was also greater than pre-exercise data (p < 0.05). The current findings confirm that high-volume resistance exercise schemes can stimulate greater C secretion because of higher metabolic demand. In terms of practical applications, acute changes in C may be used to evaluate the metabolic demands of different resistance exercise schemes, or as a tool for monitoring training strain. PMID:21572351

  13. Inhibition of thyrotropin response to TSH-releasing hormone by thyroxine in hypothyroid rats

    SciTech Connect

    Boado, R.J.; Zaninovich, A.A.; Ulloa, E.R.; Fernandez Pol, J.A.

    1985-05-01

    Pharmacological amounts of throxine (T4) can inhibit the thyrotropin (TSH) response to TSH-releasing hormone (TRH) before its conversion to triiodothyronine (T3) in the hypophysis of euthyroid rate. The present work tested physiological doses of T4 in hypothyroid rats. Rats were treated with iopanoic acid (IOP) 5 mg/100 g BW 24, 12 and 1.5 hours preceding the study, to prevent intrapituitary conversion of T4 to T3. Nonradioactive T4 was injected iv at time 0. At 20 min a 1 ..mu..g/100 g BW dose of TRH was injected iv. Blood samples were drawn at times 0, 20, and 30 min for determination by radioimmunoassay of plasma T4, T3, and TSH. In untreated rats basal TSH was 1450 +- 200 (SEM) ..mu..U/ml. At 20 min it was 105 +- 12% the basal value and at 30 min (10 min post-TRH) plasma TSH rose to 165 +- 14%. In T4-treated rats, those injected with IOP or with the vehicle alone both had the TSH response suppressed. IOP reduced intrapitutiary T3 from 4.6 +- 2.4 to 0.5 +- 0.2 fmol/min/gland. Thirty min. following the iv injection of 150 ..mu..Ci of double-labeled /sup 125/I-T4, the in vitro cytoplasmic radioactivity in control rats was 1.3 +- 0.13 x 10-/sup 2/% of the injected dose (75% T4, 17% T3), while in nuclei it was 4.2 +- 3.6 x 10-/sup 3/% (5l% T4, 28% T3). The injection of 25 ..mu..g of nonradioactive T4 decreased /sup 125/I-T4 in cytoplasm with no changes in nuclei. These findings suggest an intrinsic capacity of T4 to control TRH stimulation of TSH through binding to cytoplasmic receptors.

  14. Seasonal specificity of hormonal, behavioral, and coloration responses to within- and between-sex encounters in male lizards (Sceloporus undulatus).

    PubMed

    Smith, L C; John-Alder, H B

    1999-08-01

    This study reports the gender and seasonal specificity of hormonal, behavioral, and coloration responses displayed by "resident" male lizards (Sceloporus undulatus) exposed to male or female "intruders" during staged encounters in outdoor enclosures. Resident males were engaged in staged encounters with males or females for 1 h per day on 9 consecutive days during the breeding and postbreeding seasons. Male-specific responses occurred during the breeding but not the postbreeding season. These included (1) a transient increase in plasma testosterone (T) that was evident on Day 4 and had subsided by Day 10, (2) behavioral displays of aggression (full shows and chases), and (3) a lightening of dorsal integumental color. Female-specific behavioral responses (nod sets) were displayed in both seasons. Season-specific responses consisted only of a transient increase in plasma corticosterone (B) during the breeding season that was evident on Day 4 and had subsided by Day 10. Pushups were displayed in response to both genders during both seasons, although the frequency of pushups was significantly higher in response to females than to males during the postbreeding season. The coloration of residents did not change in response to male intruders during the postbreeding season or to females during either season. These results define the gender and seasonal specificity of hormonal, behavioral, and coloration responses of resident male S. undulatus in social interactions with conspecifics. Thus, our results clarify the biological significance of these responses in terms of potentially aggressive versus courtship interactions and breeding versus postbreeding contexts. PMID:10433885

  15. Stress-induced adaptive islet cell identity changes.

    PubMed

    Cigliola, V; Thorel, F; Chera, S; Herrera, P L

    2016-09-01

    The different forms of diabetes mellitus differ in their pathogenesis but, ultimately, they are all characterized by progressive islet β-cell loss. Restoring the β-cell mass is therefore a major goal for future therapeutic approaches. The number of β-cells found at birth is determined by proliferation and differentiation of pancreatic progenitor cells, and it has been considered to remain mostly unchanged throughout adult life. Recent studies in mice have revealed an unexpected plasticity in islet endocrine cells in response to stress; under certain conditions, islet non-β-cells have the potential to reprogram into insulin producers, thus contributing to restore the β-cell mass. Here, we discuss the latest findings on pancreas and islet cell plasticity upon physiological, pathological and experimental conditions of stress. Understanding the mechanisms involved in cell reprogramming in these models will allow the development of new strategies for the treatment of diabetes, by exploiting the intrinsic regeneration capacity of the pancreas. PMID:27615136

  16. Metabolic responses to adrenocorticotropic hormone (ACTH) vary with life-history stage in adult male northern elephant seals.

    PubMed

    Ensminger, David C; Somo, Derek A; Houser, Dorian S; Crocker, Daniel E

    2014-08-01

    Strong individual and life-history variation in serum glucocorticoids has been documented in many wildlife species. Less is known about variation in hypothalamic-pituitary-adrenal (HPA) axis responsiveness and its impact on metabolism. We challenged 18 free-ranging adult male northern elephant seals (NES) with an intramuscular injection of slow-release adrenocorticotropic hormone (ACTH) over 3 sample periods: early in the breeding season, after 70+ days of the breeding fast, and during peak molt. Subjects were blood sampled every 30 min for 2h post-injection. Breeding animals were recaptured and sampled at 48 h. In response to the ACTH injection, cortisol increased 4-6-fold in all groups, and remained elevated at 48 h in early breeding subjects. ACTH was a strong secretagogue for aldosterone, causing a 3-8-fold increase in concentration. Cortisol and aldosterone responses did not vary between groups but were correlated within individuals. The ACTH challenge produced elevations in plasma glucose during late breeding and molting, suppressed testosterone and thyroid hormone at 48 h in early breeding, and increased plasma non-esterified fatty acids and ketoacids during molting. These data suggest that sensitivity of the HPA axis is maintained but the metabolic impacts of cortisol and feedback inhibition of the axis vary with life history stage. Strong impacts on testosterone and thyroid hormone suggest the importance of maintaining low cortisol levels during the breeding fast. These data suggest that metabolic adaptations to extended fasting in NES include alterations in tissue responses to hormones that mitigate deleterious impacts of acute or moderately sustained stress responses. PMID:24798580

  17. Isolation of Pancreatic Islets from Nonhuman Primates.

    PubMed

    Berman, Dora M

    2016-01-01

    Nonhuman primates (NHP) constitute a highly relevant pre-clinical animal model to develop strategies for beta cell replacement. The close phylogenetic and immunologic relationship between NHP and humans results in cross-reactivity of various biological agents with NHP cells, as well as a very similar cytoarchitecture between islets from human and NHP that is strikingly different from that observed in rodent islets. The composition and location of endocrine cells in human or NHP islets, randomly distributed and associated with blood vessels, have functional consequences and a predisposition for paracrine interactions. Furthermore, translation of approaches that proved successful in rodent models to the clinic has been limited. Consequently, data collected from NHP studies can form the basis for an IND submission to the FDA. This chapter describes in detail the key aspects for isolation of islets from NHP, from organ procurement up to assessment of islet function, comparing and emphasizing the similarities between isolation procedures for human and NHP islets. PMID:27586422

  18. DEVELOPMENTAL THYROID HORMONE INSUFFICIENCY ALTERS THE AMPLITUDE OF THE ACOUSTIC STARTLE RESPONSE IN RATS

    EPA Science Inventory

    Purpose: The thyroid hormone (TH) system is one of the targets of endocrine disrupting chemicals. Since TH is essential for proper brain development, disruption by exposure to chemicals during development can result in adverse neurological outcomes. Previous studies revealed th...

  19. Revascularization of pancreatic islet allografts is enhanced by α-1-antitrypsin under anti-inflammatory conditions.

    PubMed

    Bellacen, Keren; Kalay, Noa; Ozeri, Eyal; Shahaf, Galit; Lewis, Eli C

    2013-01-01

    Pancreatic islets are a highly vascularized entity, and their transplantation into diabetic individuals requires optimal revascularization. In addition, β-cells in islets are extremely sensitive to inflammation. α-1-Antitrypsin (AAT), a circulating serine-protease inhibitor that is available for clinical use as an affinity-purified human product, has been shown to protect islets from graft failure in mouse transplantation models and to achieve readily vascularized islet grafts. AAT is known to induce vascular endothelial growth factor (VEGF) expression and release, as well as protect from proteolytic cleavage of VEGF by elastase, promote viability of endothelial cells, and enhance migration of myocytes. Our aim was to examine whether AAT enhances vasculogenesis toward islet grafts. We employed Matrigel-islet plugs as means to introduce islets in an explantable isolated compartment and examined vessel formation, vessel maturation, and inflammatory profile of explants 9 days after implantation. Also, we examined primary epithelial cell grafts that were prepared from lungs of mice that are transgenic for human AAT. In addition, aortic ring sprouting assay was performed, and HUVEC tube formation assays were studied in the presence of AAT. Our findings indicate that islet grafts exhibit mature vessels in the presence of AAT, as demonstrated by morphology, as well as expression of endothelial CD31, smooth muscle actin (SMA), and von Willebrand factor (vWF). Epithelial cells that express human AAT achieved a similar positive outcome. Aortic ring sprouting was enhanced in AAT-treated cultures and also in cultures that contained primary epithelial cells from human AAT transgenic animals in the absence of added AAT. According to the tube formation assay, HUVECs exhibited superior responses in the presence of AAT. We conclude that vasculogenesis toward islet grafts is enhanced in the presence of AAT. Together with the remarkable safety profile of AAT, the study supports its

  20. The effect of Yohimbine, an alpha2 adrenergic receptor antagonist, on the growth hormone response to apomorphine in normal subjects.

    PubMed Central

    Lal, S; Thavundayil, J X; Krishnan, B; Nair, N P; Schwartz, G; Guyda, H

    1996-01-01

    Yohimbine HCl (16 mg po) administered 30 min before clonidine (CLON) (2 ug/kg infused over 10 min) (N = 5) or apomorphine HCl (Apo) (0.5 mg sc) (N = 10) antagonized the growth hormone (GH) response to CLON but had no effect on the GH response to Apo in normal men. This finding suggests that in humans, alpha2 adrenergic mechanisms do not modulate dopaminergic function, at least not in the hypothalamic-pituitary axis, and that the GH response to Apo is not mediated via an alpha2 adrenergic link. PMID:8820174

  1. The potential benefit of non-purified islets preparations for islet transplantation.

    PubMed

    Webb, M'Balu A; Dennison, Ashley R; James, Roger F

    2012-01-01

    Since the advent of islet transplantation, there has been a significant emphasis on the importance of islet purity despite an inevitable associated loss of islet mass during the purification process. One of the key elements of the 'Edmonton Protocol' for islet transplantation published in 2000 was an emphasis on the need for sequential transplants of highly purified islets (averaging 24% beta cell purity) and the close correlation between the numbers of islets transplanted and the success of the procedure. However, the emphasis on islet purity may warrant further consideration as auto transplantation of non-purified islets currently provides the most successful insulin independence rates within the field of islet transplantation. While the role of auto and allo immunity could contribute to the differences in the success rates it is clear that within the clinical setting, significant acinar and ductal contamination is well tolerated. However, one could go further and hypothesize that extra-insular tissue including acinar tissue, ductal tissue, peri-pancreatic lymph nodes and vascular tissue actually confer an advantage to islet survival/function and may even contribute to the insulin secreting capacity of the graft post transplant. As such this review will assess the influence of extra-insular pancreatic tissue on the results of islet transplantation based on published evidence and will also explore the possibility that non-islet pancreatic cells are capable of differentiating into a beta cell phenotype in vivo contributing to an ongoing regeneration of endocrine mass during the period following transplantation. PMID:22616483

  2. Rotational Transport of Islets: The Best Way for Islets to Get around?

    PubMed Central

    Oberhuber, Rupert; Zelger, Bettina; Pirkebner, Daniela; Draxl, Anna; Resch, Thomas; Margreiter, Christian; Sucher, Robert; Margreiter, Raimund; Pratschke, Johann; Hengster, Paul; Hermann, Martin

    2013-01-01

    Islet transplantation is a valid treatment option for patients suffering from type 1 diabetes mellitus. To assure optimal islet cell quality, specialized islet isolation facilities have been developed. Utilization of such facilities necessitates transportation of islet cells to distant institutions for transplantation. Despite its importance, a clinically feasible solution for the transport of islets has still not been established. We here compare the functionality of isolated islets from C57BL/6 mice directly after the isolation procedure as well as after two simulated transport conditions, static versus rotation. Islet cell quality was assessed using real-time live confocal microscopy. In vivo islet function after syngeneic transplantation was determined by weight and blood sugar measurements as well as by intraperitoneal glucose tolerance tests. Vascularization of islets was documented by fluorescence microscopy and immunohistochemistry. All viability parameters documented comparable cell viability in the rotary group and the group transplanted immediately after isolation. Functional parameters assessed in vivo displayed no significant difference between these two groups. Moreover, vascularization of islets was similar in both groups. In conclusion, rotary culture conditions allows the maintenance of highest islet quality for at least 15 h, which is comparable to that of freshly isolated islets. PMID:24324977

  3. Pancreas preservation for pancreas and islet transplantation

    PubMed Central

    Iwanaga, Yasuhiro; Sutherland, David E.R.; Harmon, James V.; Papas, Klearchos K.

    2010-01-01

    Purpose of review To summarize advances and limitations in pancreas procurement and preservation for pancreas and islet transplantation, and review advances in islet protection and preservation. Recent findings Pancreases procured after cardiac death, with in-situ regional organ cooling, have been successfully used for islet transplantation. Colloid-free Celsior and histidine-tryptophan-ketoglutarate preservation solutions are comparable to University of Wisconsin solution when used for cold storage before pancreas transplantation. Colloid-free preservation solutions are inferior to University of Wisconsin solution for pancreas preservation prior to islet isolation and transplantation. Clinical reports on pancreas and islet transplants suggest that the two-layer method may not offer significant benefits over cold storage with the University of Wisconsin solution: improved oxygenation may depend on the graft size; benefits in experimental models may not translate to human organs. Improvements in islet yield and quality occurred from pancreases treated with inhibitors of stress-induced apoptosis during procurement, storage, isolation or culture. Pancreas perfusion may be desirable before islet isolation and transplantation and may improve islet yields and quality. Methods for real-time, noninvasive assessment of pancreas quality during preservation have been implemented and objective islet potency assays have been developed and validated. These innovations should contribute to objective evaluation and establishment of improved pancreas preservation and islet isolation strategies. Summary Cold storage may be adequate for preservation before pancreas transplants, but insufficient when pancreases are processed for islets or when expanded donors are used. Supplementation of cold storage solutions with cytoprotective agents and perfusion may improve pancreas and islet transplant outcomes. PMID:18685343

  4. Isolated human islets contain a distinct population of mesenchymal stem cells.

    PubMed

    Carlotti, Françoise; Zaldumbide, Arnaud; Loomans, Cindy J; van Rossenberg, Evelien; Engelse, Marten; de Koning, Eelco J; Hoeben, Rob C

    2010-01-01

    Islet replacement is a promising approach for type-1 diabetes treatment, but the shortage of organ donors demands new sources of β-cells. The use of stem/precursor cells may represent an attractive alternative. Islet-derived stem/precursor cells (hIPC) have been isolated from human islet preparations, but neither their origin, nor their contribution to β-cell formation in the adult pancreas, are well understood. To study these cells in more detail hIPC were isolated from purified human islets, cultured and functionally characterized. Cultured hIPC did not express the genes for endocrine hormones. These cells exhibited the capacity to aggregate and form clusters when transferred to serum-free medium. In these clusters the expression of insulin, glucagon, and somatostatin genes is induced. Human IPC lack expression of Von Willebrand Factor, CD31, CD34, CD45, and CK19 and CA19.9, demonstrating that hIPC are neither of hematopoietic, endothelial, nor of ductal origin. The mesenchymal stem cells (MSC) markers CD105, CD90, CD73, CD44, CD29, and CD13 are expressed, as well as nestin and vimentin. With the appropriate stimuli the cells can differentiate into adipocytes and osteoblasts lineages. Also hIPC express the pericyte markers CD146, NG2, αSMA and PDGF-Rβ. Immunoflowcytometry revealed that human islets contain 2.0 ± 0.8% of CD105/CD90 double-positive cells. Confocal microscopy showed that these cells reside within the human islets. Altogether our data revealed the presence of a distinct MSC-like stem cell population in isolated human islets. PMID:21099310

  5. Endothelial Cells Derived from the Blood-Brain Barrier and Islets of Langerhans Differ in their Response to the Effects of Bilirubin on Oxidative Stress Under Hyperglycemic Conditions.

    PubMed

    Kapitulnik, Jaime; Benaim, Clara; Sasson, Shlomo

    2012-01-01

    Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS). High glucose levels (hyperglycemia) generate reactive metabolites. Endothelial cell dysfunction, an early vascular complication in diabetes, has been associated with hyperglycemia-induced oxidative stress. Both glucose and UCB are substrates for transport proteins in microvascular endothelial cells of the blood-brain barrier (BBB). In the current study we show that UCB (1-40 μM) induces apoptosis and reduces survival of bEnd3 cells, a mouse brain endothelial cell line which serves as an in vitro model of the BBB. These deleterious effects of UCB were enhanced in the presence of high glucose (25 mM) levels. Interestingly, the bEnd3 cells exhibited an increased sensitivity to the apoptotic effects of UCB when compared to the MS1 microcapillary endothelial cell line. MS1 cells originate from murine pancreatic islets of Langerhans, and are devoid of the barrier characteristics of BBB-derived endothelial cells. ROS production was increased in both bEnd3 and MS1 cells exposed to high glucose, as compared with cells exposed to normal (5.5 mM) glucose levels. While UCB (0.1-40 μM) did not alter ROS production in cells exposed to normal glucose, relatively low ("physiological") UCB concentrations (0.1-5 μM) attenuated ROS generation in both cell lines exposed to high glucose levels. Most strikingly, higher UCB concentrations (20-40 μM) increased ROS generation in bEnd3 cells exposed to high glucose, but not in similarly treated MS1 cells. These results may be of critical importance for understanding the vulnerability of the BBB endothelium upon exposure to increasing UCB levels under hyperglycemic conditions

  6. Endothelial Cells Derived from the Blood-Brain Barrier and Islets of Langerhans Differ in their Response to the Effects of Bilirubin on Oxidative Stress Under Hyperglycemic Conditions

    PubMed Central

    Kapitulnik, Jaime; Benaim, Clara; Sasson, Shlomo

    2012-01-01

    Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS). High glucose levels (hyperglycemia) generate reactive metabolites. Endothelial cell dysfunction, an early vascular complication in diabetes, has been associated with hyperglycemia-induced oxidative stress. Both glucose and UCB are substrates for transport proteins in microvascular endothelial cells of the blood-brain barrier (BBB). In the current study we show that UCB (1–40 μM) induces apoptosis and reduces survival of bEnd3 cells, a mouse brain endothelial cell line which serves as an in vitro model of the BBB. These deleterious effects of UCB were enhanced in the presence of high glucose (25 mM) levels. Interestingly, the bEnd3 cells exhibited an increased sensitivity to the apoptotic effects of UCB when compared to the MS1 microcapillary endothelial cell line. MS1 cells originate from murine pancreatic islets of Langerhans, and are devoid of the barrier characteristics of BBB-derived endothelial cells. ROS production was increased in both bEnd3 and MS1 cells exposed to high glucose, as compared with cells exposed to normal (5.5 mM) glucose levels. While UCB (0.1–40 μM) did not alter ROS production in cells exposed to normal glucose, relatively low (“physiological”) UCB concentrations (0.1–5 μM) attenuated ROS generation in both cell lines exposed to high glucose levels. Most strikingly, higher UCB concentrations (20–40 μM) increased ROS generation in bEnd3 cells exposed to high glucose, but not in similarly treated MS1 cells. These results may be of critical importance for understanding the vulnerability of the BBB endothelium upon exposure to increasing UCB levels under hyperglycemic

  7. Fibrillar dimer formation of islet amyloid polypeptides

    DOE PAGESBeta

    Chiu, Chi -cheng; de Pablo, Juan J.

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimentalmore » and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.« less

  8. Systemic above- and belowground cross talk: hormone-based responses triggered by Heterodera schachtii and shoot herbivores in Arabidopsis thaliana

    PubMed Central

    Kammerhofer, Nina; Egger, Barbara; Dobrev, Petre; Vankova, Radomira; Hofmann, Julia; Schausberger, Peter; Wieczorek, Krzysztof

    2015-01-01

    Above- and belowground plant parts are simultaneously attacked by different pests and pathogens. The host mediates these interactions and physiologically reacts, e.g. with local and systemic alterations of endogenous hormone levels coupled with coordinated transcriptional changes. This in turn affects attractiveness and susceptibility of the plant to subsequent attackers. Here, the model plant Arabidopsis thaliana is used to study stress hormone-based systemic responses triggered by simultaneous root parasitism by the cyst nematode Heterodera schachtii and shoot herbivory by the thrips Frankliniella occidentalis and the spider mite Tetranychus urticae. First, HPLC/MS and quantitative reverse transcriptase PCR are used to show that nematode parasitism strongly affects stress hormone levels and expression of hormone marker genes in shoots. Previous nematode infection is then demonstrated to affect the behavioural and life history performance of both arthropods. While thrips explicitly avoid nematode-infected plants, spider mites prefer them. In addition, the life history performance of T. urticae is significantly enhanced by nematode infection. Finally, systemic changes triggered by shoot-feeding F. occidentalis but not T. urticae are shown to make the roots more attractive for H. schachtii. This work emphasises the importance of above- and belowground signalling and contributes to a better understanding of plant systemic defence mechanisms against plant-parasitic nematodes. PMID:26324462

  9. Systemic above- and belowground cross talk: hormone-based responses triggered by Heterodera schachtii and shoot herbivores in Arabidopsis thaliana.

    PubMed

    Kammerhofer, Nina; Egger, Barbara; Dobrev, Petre; Vankova, Radomira; Hofmann, Julia; Schausberger, Peter; Wieczorek, Krzysztof

    2015-12-01

    Above- and belowground plant parts are simultaneously attacked by different pests and pathogens. The host mediates these interactions and physiologically reacts, e.g. with local and systemic alterations of endogenous hormone levels coupled with coordinated transcriptional changes. This in turn affects attractiveness and susceptibility of the plant to subsequent attackers. Here, the model plant Arabidopsis thaliana is used to study stress hormone-based systemic responses triggered by simultaneous root parasitism by the cyst nematode Heterodera schachtii and shoot herbivory by the thrips Frankliniella occidentalis and the spider mite Tetranychus urticae. First, HPLC/MS and quantitative reverse transcriptase PCR are used to show that nematode parasitism strongly affects stress hormone levels and expression of hormone marker genes in shoots. Previous nematode infection is then demonstrated to affect the behavioural and life history performance of both arthropods. While thrips explicitly avoid nematode-infected plants, spider mites prefer them. In addition, the life history performance of T. urticae is significantly enhanced by nematode infection. Finally, systemic changes triggered by shoot-feeding F. occidentalis but not T. urticae are shown to make the roots more attractive for H. schachtii. This work emphasises the importance of above- and belowground signalling and contributes to a better understanding of plant systemic defence mechanisms against plant-parasitic nematodes. PMID:26324462

  10. Thyroid Hormone Receptor α Plays an Essential Role in Male Skeletal Muscle Myoblast Proliferation, Differentiation, and Response to Injury.

    PubMed

    Milanesi, Anna; Lee, Jang-Won; Kim, Nam-Ho; Liu, Yan-Yun; Yang, An; Sedrakyan, Sargis; Kahng, Andrew; Cervantes, Vanessa; Tripuraneni, Nikita; Cheng, Sheue-yann; Perin, Laura; Brent, Gregory A

    2016-01-01

    Thyroid hormone plays an essential role in myogenesis, the process required for skeletal muscle development and repair, although the mechanisms have not been established. Skeletal muscle develops from the fusion of precursor myoblasts into myofibers. We have used the C2C12 skeletal muscle myoblast cell line, primary myoblasts, and mouse models of resistance to thyroid hormone (RTH) α and β, to determine the role of thyroid hormone in the regulation of myoblast differentiation. T3, which activates thyroid hormone receptor (TR) α and β, increased myoblast differentiation whereas GC1, a selective TRβ agonist, was minimally effective. Genetic approaches confirmed that TRα plays an important role in normal myoblast proliferation and differentiation and acts through the Wnt/β-catenin signaling pathway. Myoblasts with TRα knockdown, or derived from RTH-TRα PV (a frame-shift mutation) mice, displayed reduced proliferation and myogenic differentiation. Moreover, skeletal muscle from the TRα1PV mutant mouse had impaired in vivo regeneration after injury. RTH-TRβ PV mutant mouse model skeletal muscle and derived primary myoblasts did not have altered proliferation, myogenic differentiation, or response to injury when compared with control. In conclusion, TRα plays an essential role in myoblast homeostasis and provides a potential therapeutic target to enhance skeletal muscle regeneration. PMID:26451739

  11. Pituitary adenylate cyclase-activating polypeptide (PACAP) is an islet substance serving as an intra-islet amplifier of glucose-induced insulin secretion in rats.

    PubMed Central

    Yada, T; Sakurada, M; Ishihara, H; Nakata, M; Shioda, S; Yaekura, K; Hamakawa, N; Yanagida, K; Kikuchi, M; Oka, Y

    1997-01-01

    1. We examined whether pituitary adenylate cyclase-activating polypeptide with 38 or 27 residues (PACAP-38 or PACAP-27) serves as an intra-islet regulator of glucose-induced insulin secretion in rats. PACAP antiserum specific for PACAP-38 and PACAP-27 was used to neutralize the effect of endogenous PACAP in islets. PACAP release from islets was bioassayed using the response of cytosolic Ca2+ concentration ([Ca2+]i) in single beta-cells, monitored by dual-wavelength fura-2 microfluorometry. Expression of PACAP mRNA was studied by reverse transcription-polymerase chain reaction (RT-PCR), while expression of PACAP was studied by metabolic labelling and immunoblotting. Localization of PACAP receptors was studied immunohistochemically. 2. High glucose-stimulated insulin release from isolated islets was attenuated by PACAP antiserum but not by non-immune sera. 3. The islet incubation medium with high glucose (Med) possessed a capacity, which was neutralized by PACAP antiserum, to increase [Ca2+]i in beta-cells. PACAP antiserum also neutralized the [Ca2+]i-increasing action of synthetic PACAP-38 and PACAP-27, but not that of vasoactive intestinal polypeptide (VIP) and glucagon. 4. Both Med and synthetic PACAP increased [Ca2+]i in beta-cells only in the presence of stimulatory, but not basal, glucose concentrations. In contrast, ATP, a substance that is known to be released from beta-cells, increased [Ca2+]i in beta-cells at both and stimulatory glucose concentrations. 5. Expression of PACAP mRNA and biosynthesis of PACAP-38 were detected in islets and a beta-cell line, MIN6. 6. Immunoreactivity for PACAP-selective type-I receptor was observed in islets. 7. [Ca2+]i measurements combined with immunocytochemistry with insulin antiserum revealed a substantial population of glucose-unresponsive beta-cells, many of which were recruited by PACAP-38 into [Ca2+]i responses. 8. These results indicate that PACAP-38 is a novel islet substance that is synthesized and released by islet

  12. Ambient temperature and the pituitary hormone responses to exercise in humans.

    PubMed

    Bridge, M W; Weller, A S; Rayson, M; Jones, D A

    2003-09-01

    Pituitary hormones have an important role during exercise yet relatively little is known about the stimulus for their release. Body temperature progressively increases during prolonged steady-state exercise in the heat and we have investigated the role that this may play in the release of prolactin, growth hormone and cortisol (as an indicator of adrenocorticotropic hormone) into the circulation. Fit young male subjects exercised at 73% V(O2,max) until volitional fatigue at 20 degrees C and at 35 degrees C (30% relative humidity at both temperatures). Rectal temperature and mean skin temperature were monitored and blood samples analysed for lactate, glucose, cortisol, growth hormone and prolactin concentrations. During the first 20 min, core temperature rose continuously and to a similar extent at both temperatures, while mean skin temperature was approximately 4 degrees C lower during exercise in the cool. Blood glucose concentration was essentially constant throughout the period of exercise while lactate concentration increased in the first 10 min and then remained constant with very similar changes in the two exercise conditions. Prolactin and growth hormone concentrations both increased during the exercise period while the concentration of cortisol declined slightly before rising slightly over the 40 min period. Prolactin release was significantly greater when exercise was carried out in the heat while there was no difference in the release of growth hormone or cortisol in the two conditions. When plotted as a function of rectal temperature, growth hormone concentration showed a linear relationship which was the same at ambient temperatures of 35 degrees C and 20 degrees C. Prolactin concentration had a curvilinear relationship with rectal temperature and this differed markedly at the two ambient temperatures. Cortisol concentration showed no dependence on any measure of body temperature. Our results are consistent with some aspect of body temperature being a

  13. Role of adipokinetic hormone and adenosine in the anti-stress response in Drosophila melanogaster.

    PubMed

    Zemanová, Milada; Stašková, Tereza; Kodrík, Dalibor

    2016-01-01

    The role of adipokinetic hormone (AKH) and adenosine in the anti-stress response was studied in Drosophila melanogaster larvae and adults carrying a mutation in the Akh gene (Akh(1)), the adenosine receptor gene (AdoR(1)), or in both of these genes (Akh(1) AdoR(1) double mutant). Stress was induced by starvation or by the addition of an oxidative stressor paraquat (PQ) to food. Mortality tests revealed that the Akh(1) mutant was the most resistant to starvation, while the AdoR(1) mutant was the most sensitive. Conversely, the Akh(1) AdoR(1) double mutant was more sensitive to PQ toxicity than either of the single mutants. Administration of PQ significantly increased the Drome-AKH level in w(1118) and AdoR(1) larvae; however, this was not accompanied by a simultaneous increase in Akh gene expression. In contrast, PQ significantly increased the expression of the glutathione S-transferase D1 (GstD1) gene. The presence of both a functional adenosine receptor and AKH seem to be important for the proper control of GstD1 gene expression under oxidative stress, however, the latter appears to play more dominant role. On the other hand, differences in glutathione S-transferase (GST) activity among the strains, and between untreated and PQ-treated groups were minimal. In addition, the glutathione level was significantly lower in all untreated AKH- or AdoR-deficient mutant flies as compared with the untreated control w(1118) flies and further declined following treatment with PQ. All oxidative stress characteristics modified by mutations in Akh gene were restored or even improved by 'rescue' mutation in flies which ectopically express Akh. Thus, the results of the present study demonstrate the important roles of AKH and adenosine in the anti-stress response elicited by PQ in a D. melanogaster model, and provide the first evidence for the involvement of adenosine in the anti-oxidative stress response in insects. PMID:27374982

  14. Vitamin D status and parathyroid hormone concentrations influence the skeletal response to zoledronate and denosumab.

    PubMed

    Mosali, P; Bernard, L; Wajed, J; Mohamed, Z; Ewang, M; Moore, A; Fogelman, I; Hampson, G

    2014-05-01

    Studies suggest that optimal vitamin D status is required for the maximal effect of antiresorptive agents. We investigated the relationship between vitamin D status, serum parathyroid hormone (PTH) concentrations, and change in bone mineral density (BMD) following iv zoledronate and denosumab. We carried out a retrospective analysis of 111 patients, mean age 70 (SD 13) years, 89 women and 22 men, prescribed zoledronate and 43 postmenopausal women treated with denosumab for osteoporosis. We measured BMD at the lumbar spine (LS) and total hip (TH), serum 25 (OH) vitamin D, PTH, and bone turnover markers (plasma CTX, P1NP) at 1 year. In patients on zoledronate, BMD increased at the LS and TH (mean LS change [SEM] = 2.6 % [0.5 %], mean TH change = 1.05 % [0.5 %], p < 0.05). A significant increase in BMD was seen at the LS only in the denosumab group (p = 0.001). Significant decreases in CTX and P1NP were observed at 12 months in both treatment groups. At baseline and at 12 months, 34 % and 23 % of the patients on zoledronate had a serum vitamin D of <50 nmol/L, respectively. The mean PTH concentration in patients with 25 (OH) vitamin D <50 nmol/L was 44 ng/L (SEM 16.6). Patients with PTH concentration <44 ng/L had significantly higher increases in TH BMD compared to those with PTH >44 ng/L (zoledronate 1.9 [0.83] vs. -0.43 [0.81], p = 0.04; denosumab 4.1 [0.054] vs. -1.7 [0.04], p = 0.004). Optimal vitamin D status and PTH concentrations improve the skeletal response to zoledronate and denosumab. PMID:24509506

  15. Thyroid hormone regulation of Sirtuin 1 expression and implications to integrated responses in fasted mice.

    PubMed

    Cordeiro, Aline; de Souza, Luana Lopes; Oliveira, Lorraine Soares; Faustino, Larissa Costa; Santiago, Letícia Aragão; Bloise, Flavia Fonseca; Ortiga-Carvalho, Tania Maria; Almeida, Norma Aparecida Dos Santos; Pazos-Moura, Carmen Cabanelas

    2013-02-01

    Sirtuin 1 (SIRT1), a NAD(+)-dependent deacetylase, has been connected to beneficial effects elicited by calorie restriction. Physiological adaptation to starvation requires higher activity of SIRT1 and also the suppression of thyroid hormone (TH) action to achieve energy conservation. Here, we tested the hypothesis that those two events are correlated and that TH may be a regulator of SIRT1 expression. Forty-eight-hour fasting mice exhibited reduced serum TH and increased SIRT1 protein content in liver and brown adipose tissue (BAT), and physiological thyroxine replacement prevented or attenuated the increment of SIRT1 in liver and BAT of fasted mice. Hypothyroid mice exhibited increased liver SIRT1 protein, while hyperthyroid ones showed decreased SIRT1 in liver and BAT. In the liver, decreased protein is accompanied by reduced SIRT1 activity and no alteration in its mRNA. Hyperthyroid and hypothyroid mice exhibited increases and decreases in food intake and body weight gain respectively. Food-restricted hyperthyroid animals (pair-fed to euthyroid group) exhibited liver and BAT SIRT1 protein levels intermediary between euthyroid and hyperthyroid mice fed ad libitum. Mice with TH resistance at the liver presented increased hepatic SIRT1 protein and activity, with no alteration in Sirt1 mRNA. These results suggest that TH decreases SIRT1 protein, directly and indirectly, via food ingestion control and, in the liver, this reduction involves TRβ. The SIRT1 reduction induced by TH has important implication to integrated metabolic responses to fasting, as the increase in SIRT1 protein requires the fasting-associated suppression of TH serum levels. PMID:23151359

  16. A polymorphism in the leptin receptor gene at position 223 is associated with growth hormone replacement therapy responsiveness in idiopathic short stature and growth hormone deficiency patients.

    PubMed

    Su, Pen-Hua; Yang, Shun-Fa; Yu, Ju-Shan; Chen, Suh-Jen; Chen, Jia-Yuh

    2012-12-01

    We hypothesized that responses to growth hormone (GH) therapy by idiopathic short stature (ISS) and growth hormone deficiency (GHD) patients were associated with single nucleotide polymorphisms (SNPs) in the leptin (LEP) and leptin receptor (LEPR) genes. We retrospectively enrolled ISS (n = 32) and GHD (n = 38) patients and forty healthy age-and gender-matched children. They were genotyped for the LEP promoter at nt.-2548, and LEPR K109R and LEPR Q223R polymorphisms. Clinical and laboratory variables were determined before and after 2 years of GH treatment. ISS patients with G/A or A/A genotypes of the LEPR Q223R SNP had a significantly higher height velocity (cm/y) than ISS patients with the G/G genotype at 2 years after GH treatment. For GHD patients, G/A or A/A genotype of the LEPR K109R SNP was associated with higher body weight, higher BMI, and higher weight velocity than patients with the G/G genotype before GH treatment, but not after GH treatment. G/A or A/A genotype of the LEPR Q223R SNP was associated with a significantly higher body weight, higher height velocity before treatment, but not after GH treatment. G/A or A/A genotype of the LEPR Q223R SNP was associated with a significantly higher weight velocity before treatment, but a significantly lower weight velocity was found at 2 years after GH treatment. These results suggest LEPR Q223R SNP (rs1137101) is associated with outcomes of GH replacement therapy in ISS and GHD patients. PMID:23009903

  17. Characterization of a novel functional protein in the pancreatic islet: IHoP regulation of glucagon synthesis in alpha-cells

    PubMed Central

    Oh, Seh-Hoon; Darwiche, Houda; Cho, Jae-Hyoung; Shupe, Thomas; Petersen, Bryon E.

    2011-01-01

    Objective We have identified a novel protein in bone marrow (BM)-derived insulin-producing cells (IPCs). Here we characterize this protein, hereby named Islet Homeostasis Protein (IHoP), in the pancreatic islet. Methods Detection of IHoP mRNA and protein were performed using RT-PCR, immunocytochemistry and in-situ hybridization. IHoP functions were utilizing proliferation, insulin secretion by in vitro assays, and as well as following siRNA protocols for suppression of IHoP. Results We found that IHoP did not homologue with known pancreatic hormones. IHoP expression was seen in both BM-derived IPCs and isolated pancreatic islets. Immunohistochemistry on pancreatic islet revealed that IHoP localized to the glucagon synthesizing α (alpha)-cells. Inhibition of IHoP by siRNA resulted in the loss of glucagon expression, which induced low blood glucose levels (63–85 mg/dL). Subsequently, cellular apoptosis was observed throughout the islet, including the insulin-producing β (beta)-cells. Islets of pre-onset diabetic patients showed normal expression of IHoP and glucagon; however IHoP was lost upon onset of the disease. Conclusion These data suggest that IHoP could be a new functional protein in the islet, and may play a role in islet homeostasis. PMID:22143342

  18. Engineered VEGF-releasing PEG-MAL hydrogel for pancreatic islet vascularization

    PubMed Central

    Phelps, Edward A.; Templeman, Kellie L.; Thulé, Peter M.; García, Andrés J.

    2013-01-01

    Biofunctionalized polyethylene glycol maleimide (PEG-MAL) hydrogels were engineered as a platform to deliver pancreatic islets to the small bowel mesentery and promote graft vascularization. VEGF, a potent stimulator of angiogenesis, was incorporated into the hydrogel to be released in an on-demand manner through enzymatic degradation. PEG-MAL hydrogel enabled extended in vivo release of VEGF. Isolated rat islets encapsulated in PEG-MAL hydrogels remained viable in culture and secreted insulin. Islets encapsulated in PEG-MAL matrix and transplanted to the small bowel mesentery of healthy rats grafted to the host tissue and revascularized by 4 weeks. Addition of VEGF release to the PEG-MAL matrix greatly augmented the vascularization response. These results establish PEG-MAL engineered matrices as a vascular-inductive cell delivery vehicle and warrant their further investigation as islet transplantation vehicles in diabetic animal models. PMID:25787738

  19. Acute Hormonal and Force Responses to Combined Strength and Endurance Loadings in Men and Women: The “Order Effect”

    PubMed Central

    S. Taipale, Ritva; Häkkinen, Keijo

    2013-01-01

    Purpose To examine acute responses and recovery of serum hormones and muscle force following combined strength (S) and endurance (E) loading sessions in which the order of exercises is reversed (ES vs. SE). Methods This cross-over study design included recreationally endurance trained men and women (age 21–45 years, n = 12 men n = 10 women) who performed both loadings. Maximal bilateral isometric strength (MVC), isometric rate of force development (RFD) and serum concentrations of testosterone (T), cortisol (C), growth hormone (GH), insulin-like growth factor 1 (IGF-1), binding protein 3 (IGFBP3) and sex hormone binding globulin (SHBG) were measured during and after both loadings. Results Both of the present combined (ES and SE) loadings led to a greater acute decrease in MVC in men than in women, while RFD was slightly affected only in men. Recovery of MVC and RFD to baseline was complete at 24 h regardless of the order of exercises. In men, neuromuscular fatigue was accompanied by increased C concentrations observed post SE. This was followed by decreased concentrations of T at 24 h and 48 h that were significantly lower than those observed following ES. GH response in men also differed significantly post loadings. In women, only a significant difference in T between ES and SE loadings was observed at post. Conclusion These observed differences in hormonal responses despite similarities in neuromuscular fatigue in men indicate the presence of an order effect as the body was not fully recovered at 48 h following SE. These findings may be applicable in training prescription in order to optimize specific training adaptations. PMID:23408956

  20. Short-term Hormone Treatment Modulates Emotion Response Circuitry in Postmenopausal Women

    PubMed Central

    Love, Tiffany; Smith, Yolanda R.; Persad, Carol C.; Tkaczyk, Anne; Zubieta, Jon-Kar

    2010-01-01

    Objective To study the effects of combination hormone therapy (HT) on emotional processing in postmenopausal women using functional neuroimaging. Design A randomized, double-blind placebo-controlled cross-over study was performed. Setting A tertiary care university medical center. Participants Ten healthy postmenopausal women (mean age 56.9 years, S.D. = 1.4) were recruited. Interventions Women were randomized to the order they received combined hormone therapy, 5 ug ethinyl estradiol and 1 mg norethindrone acetate, and placebo. Volunteers received hormone therapy or placebo for 4 weeks, followed by a one month washout period, and then received the other treatment for 4 weeks. Subjects participated in an fMRI emotional processing task, where they were asked to rate emotional pictures as positive, negative, or neutral. Main Outcome Measure Brain activation patterns were compared between hormone therapy and placebo conditions within subjects. Results During negative emotional presentations, after subtracting the effect of neutral images, areas of significant differences between HT and placebo conditions were identified in the orbital, frontal, cingulate and occipital cortices. During positive emotional image presentation there were significant differences between placebo and HT conditions within the medial frontal cortex. Conclusions Short-term menopausal treatment with combination hormone therapy affects regional brain activity within areas implicated in emotional processing. PMID:19243753

  1. Differential neural responses to child and sexual stimuli in human fathers and non-fathers and their hormonal correlates

    PubMed Central

    Mascaro, Jennifer S.; Hackett, Patrick D.; Rilling, James K.

    2015-01-01

    Despite the well-documented importance of paternal caregiving for positive child development, little is known about the neural changes that accompany the transition to fatherhood in humans, or about how changes in hormone levels affect paternal brain function. We compared fathers of children aged 1–2 with non-fathers in terms of hormone levels (oxytocin and testosterone), neural responses to child picture stimuli, and neural responses to visual sexual stimuli. Compared to non-fathers, fathers had significantly higher levels of plasma oxytocin and lower levels of plasma testosterone. In response to child picture stimuli, fathers showed stronger activation than non-fathers within regions important for face emotion processing (caudal middle frontal gyrus [MFG]), mentalizing (temporo-parietal junction [TPJ]) and reward processing (medial orbitofrontal cortex [mOFC]). On the other hand, non-fathers had significantly stronger neural responses to sexually provocative images in regions important for reward and approach-related motivation (dorsal caudate and nucleus accumbens). Testosterone levels were negatively correlated with responses to child stimuli in the MFG. Surprisingly, neither testosterone nor oxytocin levels predicted neural responses to sexual stimuli. Our results suggest that the decline in testosterone that accompanies the transition to fatherhood may be important for augmenting empathy toward children. PMID:24882167

  2. OsERF2 controls rice root growth and hormone responses through tuning expression of key genes involved in hormone signaling and sucrose metabolism.

    PubMed

    Xiao, Guiqing; Qin, Hua; Zhou, Jiahao; Quan, Ruidang; Lu, Xiangyang; Huang, Rongfeng; Zhang, Haiwen

    2016-02-01

    Root determines plant distribution, development progresses, stress response, as well as crop qualities and yields, which is under the tight control of genetic programs and environmental stimuli. Ethylene responsive factor proteins (ERFs) play important roles in plant growth and development. Here, the regulatory function of OsERF2 involved in root growth was investigated using the gain-function mutant of OsERF2 (nsf2857) and the artificial microRNA-mediated silenced lines of OsERF2 (Ami-OsERF2). nsf2857 showed short primary roots compared with the wild type (WT), while the primary roots of Ami-OsERF2 lines were longer than those of WT. Consistent with this phenotype, several auxin/cytokinin responsive genes involved in root growth were downregulated in nsf2857, but upregulated in Ami-OsERF2. Then, we found that nsf2857 seedlings exhibited decreased ABA accumulation and sensitivity to ABA and reduced ethylene-mediated root inhibition, while those were the opposite in Ami-ERF2 plants. Moreover, several key genes involved in ABA synthesis were downregulated in nsf2857, but unregulated in Ami-ERF2 lines. In addition, OsERF2 affected the accumulation of sucrose and UDPG by mediating expression of key genes involved in sucrose metabolism. These results indicate that OsERF2 is required for the control of root architecture and ABA- and ethylene-response by tuning expression of series genes involved in sugar metabolism and hormone signaling pathways. PMID:26659593

  3. Hormonal responses of metoclopramide-treated subjects experiencing nausea or emesis during parabolic flight

    NASA Technical Reports Server (NTRS)

    Kohl, Randall L.

    1987-01-01

    The concentrations of adrenocorticotropic hormone (ACTH), vasopressin (AVP), epinephrine (EPI), and norepinephrine (NE) in 22 subjects administered 10 to 20 mg of metoclopramide prior to parabolic flight are measured. The effect of metoclopramide on motion sickness is examined. It is observed that metoclopramide is ineffective in the modulation of motion sickness due to stressful linear and angular acceleration and orbital flight, and it does not affect serum hormones prior to parabolic flight. It is detected that the serum level of AVP declines following emesis induced by parabolic flight and stressful angular acceleration; the serum levels of ACTH and EPI are elevated by parabolic flight and stressful angular acceleration; and serum NE is significantly elevated immediately following emesis. The possible roles of these hormones in the etiology of space motion sickness are discussed.

  4. Standard of Care and Controversies in the Adjuvant Endocrine Treatment of Hormone-Responsive Early Breast Cancer

    PubMed Central

    Bauerschlag, Dirk O.; Maass, Nicolai; Schem, Christian

    2014-01-01

    Summary Hormone-responsive early breast cancer is a highly curable disease. In premenopausal women, tamoxifen (TAM) is still the standard treatment. Nowadays, up to 10 years of TAM can be safely administered, especially in women who remain premenopausal. Patients who are considered to be perimenopausal should be initially treated like premenopausal patients. Depending on their serum hormone levels, these patients can be safely switched to an aromatase inhibitor (AI) therapy once the estradiol (E2) and follicle-stimulating hormone (FSH) levels prove the established postmenopausal status. In postmenopausal women, several sequences of endocrine treatment are available. The AI therapy can be induced upfront or sequentially by switching from Tam to AI and vice versa. Extended endocrine therapy, by adding up to 5 years of letrozole after 5 years of TAM, has also been proven to be beneficial in certain patient subgroups. Genotyping of cytochromes such as CYP2D6 did not have any added value in identifying patients who are at higher risk of recurrence. Nevertheless, in all patients the side effects need to be given high consideration. New strategies developed to overcome endocrine resistance are tested in clinical studies. New co-administered drugs such as specific inhibitors of mammalian target of rapamycin (mTOR), Src, or phosphatidylinositol 3-kinase (PI3K) do improve endocrine responsiveness in metastatic disease and will eventually be introduced in the treatment of early breast cancer. PMID:25404889

  5. Aging influences steroid hormone release by mink ovaries and their response to leptin and IGF-I

    PubMed Central

    Sirotkin, Alexander V.; Mertin, Dušan; Süvegová, Karin; Harrath, Abdel Halim; Kotwica, Jan

    2016-01-01

    ABSTRACT The aim of our study was to understand whether ovarian steroid hormones, and their response to the metabolic hormones leptin and IGF-I leptin, could be involved in the control of mink reproductive aging via changes in basal release of ovarian progesterone and estradiol. For this purpose, we compared the release of progesterone and estradiol by ovarian fragments isolated from young (yearlings) and old (3-5 years of age) minks cultured with and without leptin and IGF-I (0, 1, 10 or 100 ng/ml). We observed that isolated ovaries of older animals produced less progesterone but not less estradiol than the ovaries of young animals. Leptin addition stimulated estradiol release by the ovarian tissue of young animals but inhibited it in older females. Leptin did not influence progesterone output by the ovaries of either young or older animals. IGF-I inhibited estradiol output in young but not old animals, whereas progesterone release was inhibited by IGF-I irrespective of the animal age. Our observations demonstrate the involvement of both leptin and IGF-I in the control of mink ovarian steroid hormones release. Furthermore, our findings suggest that reproductive aging in minks can be due to (a) reduction in basal progesterone release and (b) alterations in the response of estradiol but not of progesterone to leptin and IGF-I. PMID:26794607

  6. Salivary steroid hormone response to whole-body cryotherapy in elite rugby players.

    PubMed

    Grasso, D; Lanteri, P; Di Bernardo, C; Mauri, C; Porcelli, S; Colombini, A; Zani, V; Bonomi, F G; Melegati, G; Banfi, G; Lombardi, G

    2014-01-01

    Saliva represents a low stress, not-invasively collected matrix that allows steroid hormone monitoring in athletes by reflecting type, intensity and duration of exercise. Whole body cryotherapy (WBC) consists of short whole-body exposures to extremely cold air (-110° to -140°C) which, despite being initially used to treat inflammatory diseases, is currently acquiring increasing popularity in sports medicine. Cryostimulation practice is now widely accepted as an effective treatment to accelerate muscle recovery in rugby players. The aim of this work was to study the changes of steroid hormones in saliva of rugby players after both 2 and 14 consecutive WBC sessions, in order to investigate the effects of the treatment on their salivary steroid hormonal profile. Twenty-five professional rugby players, belonging to the Italian National Team, underwent a 7-day cryotherapy protocol consisting of 2 daily sessions. Saliva samples were taken in the morning prior to the start of the WBC, in the evening after the end of the second WBC, and in the morning of the day after the last WBC session. The samples were analyzed for cortisol, DHEA, testosterone and estradiol using competitive enzyme-linked immunosorbent assays. Cortisol and DHEA showed a reduction already after the 2 WBC sessions of the first day; after 14 consecutive WBC sessions cortisol, DHEA, and estradiol levels decreased, while testosterone increased as did the testosterone to cortisol ratio. These results were confirmed by the fact that the majority of subjects showed variations exceeding the critical difference (CD). In conclusion, we found that WBC acutely affects the salivary steroid hormone profile, and the results are evident already after only one twice-daily session. Most significantly, after one-week of consecutive twice-daily WBC sessions, all the hormones were modified. This is the first experimental report that links changes in the hormonal asset to WBC. PMID:25001661

  7. Culture and characteristics of hormone-responsive neuroblastoma x glioma hybrid cells

    SciTech Connect

    Hamprecht, B.; Glaser, T.; Reiser, G.; Bayer, E.; Propst, F.

    1985-01-01

    Neuroblastoma x glioma hybrid cells were generated by cell fusion of the 6-thioguanine-resistant clonal mouse neuroblastoma cells and the bromodeoxyuridine-resistant rat glioma cells, selection, and cloning. Every characteristics generally ascribed to neurons has been observed with the hybrid cells. The paper explores the morphological differentiation of hybrid cells, procedures for testing the hormonal regulation of intracellular levels of cyclic, (/sup 3/H)AMP in hybrid cells, hormonal regulation of adenylate cyclase in homogenates of hyrbid cells, intracellular levels of cyclic GMP, and uptake of guanidinium ions in hybrid cells.

  8. Sequence elements in the human osteocalcin gene confer basal activation and inducible response to hormonal vitamin D sub 3

    SciTech Connect

    Kerner, S.A.; Scott, R.A.; Pike, J.W. )

    1989-06-01

    Osteoblast-specific expression of the bone protein osteocalcin is controlled at the transcriptional level by the steroid hormone 1{alpha},25-dihydroxyvitamin D{sub 3}. As this protein may represent a marker for bone activity in human disease, the authors examined the regulation of its expression at the molecular level by evaluating human osteocalcin gene promoter function. They describe regions within the promoter that contribute to basal expression of the gene in osteoblast-like cells in culture. Further, they define a 21-base-pair DNA element with the sequence 5{prime}-GTGACTCACCGGGTGAACGGG-3{prime}, which acts in cis to mediate 1{alpha},25-dihydroxyvitamin D{sub 3} inducibility of the osteocalcin gene. This response element bears sequence similarity with other short DNA segments, particularly those for estrogen and thyroid hormone, which act together with their respective trans-acting receptors to modulate gene transcription.

  9. Matrix Metalloproteinase-9 Reduces Islet Amyloid Formation by Degrading Islet Amyloid Polypeptide*

    PubMed Central

    Aston-Mourney, Kathryn; Zraika, Sakeneh; Udayasankar, Jayalakshmi; Subramanian, Shoba L.; Green, Pattie S.; Kahn, Steven E.; Hull, Rebecca L.

    2013-01-01

    Deposition of islet amyloid polypeptide (IAPP) as amyloid is a pathological hallmark of the islet in type 2 diabetes, which is toxic to β-cells. We previously showed that the enzyme neprilysin reduces islet amyloid deposition and thereby reduces β-cell apoptosis, by inhibiting fibril formation. Two other enzymes, matrix metalloproteinase (MMP)-2 and MMP-9, are extracellular gelatinases capable of degrading another amyloidogenic peptide, Aβ, the constituent of amyloid deposits in Alzheimer disease. We therefore investigated whether MMP-2 and MMP-9 play a role in reducing islet amyloid deposition. MMP-2 and MMP-9 mRNA were present in mouse islets but only MMP-9 activity was detectable. In an islet culture model where human IAPP (hIAPP) transgenic mouse islets develop amyloid but nontransgenic islets do not, a broad spectrum MMP inhibitor (GM6001) and an MMP-2/9 inhibitor increased amyloid formation and the resultant β-cell apoptosis. In contrast, a specific MMP-2 inhibitor had no effect on either amyloid deposition or β-cell apoptosis. Mass spectrometry demonstrated that MMP-9 degraded amyloidogenic hIAPP but not nonamyloidogenic mouse IAPP. Thus, MMP-9 constitutes an endogenous islet protease that limits islet amyloid deposition and its toxic effects via degradation of hIAPP. Because islet MMP-9 mRNA levels are decreased in type 2 diabetic subjects, islet MMP-9 activity may also be decreased in human type 2 diabetes, thereby contributing to increased islet amyloid deposition and β-cell loss. Approaches to increase islet MMP-9 activity could reduce or prevent amyloid deposition and its toxic effects in type 2 diabetes. PMID:23229548

  10. Hemodynamic and hormonal responses to lower body negative pressure in men with varying profiles of strength and aerobic power

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.; Mathes, K. L.; Lasley, M. L.; Tomaselli, C. M.; Frey, M. A.; Hoffler, G. W.

    1993-01-01

    Hemodynamic, cardiac, and hormonal responses to lower-body negative pressure (LBNP) were examined in 24 healthy men to test the hypothesis that responsiveness of reflex control of blood pressure during orthostatic challenge is associated with interactions between strength and aerobic power. Subjects underwent treadmill tests to determine peak oxygen uptake (VO2max) and isokinetic dynamometer tests to determine knee extensor strength. Based on predetermined criteria, subjects were classified into one of four fitness profiles of six subjects each, matched for age, height, and body mass: (a) low strength/average aerobic fitness, (b) low strength/high aerobic fitness, (c) high strength/average aerobic fitness, and (d) high strength/high aerobic fitness. Following 90 min of 0.11 rad (6 degrees) head-down tilt (HDT), each subject underwent graded LBNP to -6.7 kPa or presyncope, with maximal duration 15 min, while hemodynamic, cardiac, and hormonal responses were measured. All groups exhibited typical hemodynamic, hormonal, and fluid shift responses during LBNP, with no intergroup differences between high and low strength characteristics. Subjects with high aerobic power exhibited greater (P < 0.05) stroke volume and lower (P < 0.05) heart rate, vascular peripheral resistance, and mean arterial pressure during rest, HDT, and LBNP. Seven subjects, distributed among the four fitness profiles, became presyncopal. These subjects showed greatest reduction in mean arterial pressure during LBNP, had greater elevations in vasopressin, and lesser increases in heart rate and peripheral resistance. Neither VO2max nor leg strength were associated with fall in arterial pressure or with syncopal episodes. We conclude that interactions between aerobic and strength fitness characteristics do not influence responses to LBNP challenge.

  11. Biological regulation of receptor-hormone complex concentrations in relation to dose-response assessments for endocrine-active compounds.

    PubMed

    Andersen, M E; Barton, H A

    1999-03-01

    Some endocrine-active compounds (EACs) act as agonists or antagonists of specific hormones and may interfere with cellular control processes that regulate gene transcription. Many mechanisms controlling gene expression are universal to organisms ranging from unicellular bacteria to more complex plants and animals. One mechanism, coordinated control of batteries of gene products, is critical in adaptation of bacteria to new environments and for development and tissue differentiation in multi-cellular organisms. To coordinately activate sets of genes, all living organisms have devised molecular modules to permit transitions, or switching, between different functional states over a small range of hormone concentration, and other modules to stabilize the new state through homeostatic interactions. Both switching and homeostasis are regulated by controlling concentrations of hormone-receptor complexes. Molecular control processes for switching and homeostasis are inherently nonlinear and often utilize autoregulatory feedback loops. Among the biological processes contributing to switching phenomena are receptor autoinduction, induction of enzymes for ligand synthesis, mRNA stabilization/activation, and receptor polymerization. This paper discusses a variety of molecular switches found in animal species, devises simple quantitative models illustrating roles of specific molecular interactions in creating switching modules, and outlines the impact of these switching processes and other feedback loops for risk assessments with EACs. Quantitative simulation modeling of these switching mechanisms made it apparent that highly nonlinear dose-response curves for hormones and EACs readily arise from interactions of several linear processes acting in concert on a common control point. These nonlinear mechanisms involve amplification of response, rather than multimeric molecular interactions as in conventional Hill relationships. PMID:10330682

  12. Negative energy balance in a male songbird, the Abert's towhee, constrains the testicular endocrine response to luteinizing hormone stimulation

    PubMed Central

    Davies, Scott; Gao, Sisi; Valle, Shelley; Bittner, Stephanie; Hutton, Pierce; Meddle, Simone L.; Deviche, Pierre

    2015-01-01

    ABSTRACT Energy deficiency can suppress reproductive function in vertebrates. As the orchestrator of reproductive function, endocrine activity of the hypothalamo-pituitary–gonadal (HPG) axis is potentially an important mechanism mediating such effects. Previous experiments in wild-caught birds found inconsistent relationships between energy deficiency and seasonal reproductive function, but these experiments focused on baseline HPG axis activity and none have investigated the responsiveness of this axis to endocrine stimulation. Here, we present data from an experiment in Abert's towhees, Melozone aberti, using gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) challenges to investigate whether energy deficiency modulates the plasma testosterone responsiveness of the HPG axis. Wild-caught birds were either ad libitum fed or energetically constrained via chronic food restriction during photoinduced reproductive development. Energy deficiency did not significantly affect the development of reproductive morphology, the baseline endocrine activity of the HPG axis, or the plasma testosterone response to GnRH challenge. Energy deficiency did, however, decrease the plasma testosterone responsiveness to LH challenge. Collectively, these observations suggest that energy deficiency has direct gonadal effects consisting of a decreased responsiveness to LH stimulation. Our study, therefore, reveals a mechanism by which energy deficiency modulates reproductive function in wild birds in the absence of detectable effects on baseline HPG axis activity. PMID:26333925

  13. Discovery of molecular pathways mediating 1,25-dihydroxyvitamin D3 protection against cytokine-induced inflammation and damage of human and male mouse islets of Langerhans.

    PubMed

    Wolden-Kirk, H; Rondas, D; Bugliani, M; Korf, H; Van Lommel, L; Brusgaard, K; Christesen, H T; Schuit, F; Proost, P; Masini, M; Marchetti, P; Eizirik, D L; Overbergh, L; Mathieu, C

    2014-03-01

    Protection against insulitis and diabetes by active vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), in nonobese diabetic mice has until now mainly been attributed to its immunomodulatory effects, but also protective effects of this hormone on inflammation-induced β-cell death have been reported. The aim of this study was to clarify the molecular mechanisms by which 1,25(OH)2D3 contributes to β-cell protection against cytokine-induced β-cell dysfunction and death. Human and mouse islets were exposed to IL-1β and interferon-γ in the presence or absence of 1,25(OH)2D3. Effects on insulin secretion and β-cell survival were analyzed by glucose-stimulated insulin release and electron microscopy or Hoechst/propidium iodide staining, respectively. Gene expression profiles were assessed by Affymetrix microarrays. Nuclear factor-κB activity was tested, whereas effects on secreted chemokines/cytokines were confirmed by ELISA and migration studies. Cytokine exposure caused a significant increase in β-cell apoptosis, which was almost completely prevented by 1,25(OH)2D3. In addition, 1,25(OH)2D3 restored insulin secretion from cytokine-exposed islets. Microarray analysis of murine islets revealed that the expression of approximately 4000 genes was affected by cytokines after 6 and 24 hours (n = 4; >1.3-fold; P < .02), of which nearly 250 genes were modified by 1,25(OH)2D3. These genes belong to functional groups involved in immune response, chemotaxis, cell death, and pancreatic β-cell function/phenotype. In conclusion, these findings demonstrate a direct protective effect of 1,25(OH)2D3 against inflammation-induced β-cell dysfunction and death in human and murine islets, with, in particular, alterations in chemokine production by the islets. These effects may contribute to the beneficial effects of 1,25(OH)2D3 against the induction of autoimmune diabetes. PMID:24424042

  14. Regulation of Glucagon Secretion in Normal and Diabetic Human Islets by γ-Hydroxybutyrate and Glycine*

    PubMed Central

    Li, Changhong; Liu, Chengyang; Nissim, Itzhak; Chen, Jie; Chen, Pan; Doliba, Nicolai; Zhang, Tingting; Nissim, Ilana; Daikhin, Yevgeny; Stokes, David; Yudkoff, Marc; Bennett, Michael J.; Stanley, Charles A.; Matschinsky, Franz M.; Naji, Ali

    2013-01-01

    Paracrine signaling between pancreatic islet β-cells and α-cells has been proposed to play a role in regulating glucagon responses to elevated glucose and hypoglycemia. To examine this possibility in human islets, we used a metabolomic approach to trace the responses of amino acids and other potential neurotransmitters to stimulation with [U-13C]glucose in both normal individuals and type 2 diabetics. Islets from type 2 diabetics uniformly showed decreased glucose stimulation of insulin secretion and respiratory rate but demonstrated two different patterns of glucagon responses to glucose: one group responded normally to suppression of glucagon by glucose, but the second group was non-responsive. The non-responsive group showed evidence of suppressed islet GABA levels and of GABA shunt activity. In further studies with normal human islets, we found that γ-hydroxybutyrate (GHB), a potent inhibitory neurotransmitter, is generated in β-cells by an extension of the GABA shunt during glucose stimulation and interacts with α-cell GHB receptors, thus mediating the suppressive effect of glucose on glucagon release. We also identified glycine, acting via α-cell glycine receptors, as the predominant amino acid stimulator of glucagon release. The results suggest that glycine and GHB provide a counterbalancing receptor-based mechanism for controlling α-cell secretory responses to metabolic fuels. PMID:23266825

  15. Regulation of glucagon secretion in normal and diabetic human islets by γ-hydroxybutyrate and glycine.

    PubMed

    Li, Changhong; Liu, Chengyang; Nissim, Itzhak; Chen, Jie; Chen, Pan; Doliba, Nicolai; Zhang, Tingting; Nissim, Ilana; Daikhin, Yevgeny; Stokes, David; Yudkoff, Marc; Bennett, Michael J; Stanley, Charles A; Matschinsky, Franz M; Naji, Ali

    2013-02-01

    Paracrine signaling between pancreatic islet β-cells and α-cells has been proposed to play a role in regulating glucagon responses to elevated glucose and hypoglycemia. To examine this possibility in human islets, we used a metabolomic approach to trace the responses of amino acids and other potential neurotransmitters to stimulation with [U-(13)C]glucose in both normal individuals and type 2 diabetics. Islets from type 2 diabetics uniformly showed decreased glucose stimulation of insulin secretion and respiratory rate but demonstrated two different patterns of glucagon responses to glucose: one group responded normally to suppression of glucagon by glucose, but the second group was non-responsive. The non-responsive group showed evidence of suppressed islet GABA levels and of GABA shunt activity. In further studies with normal human islets, we found that γ-hydroxybutyrate (GHB), a potent inhibitory neurotransmitter, is generated in β-cells by an extension of the GABA shunt during glucose stimulation and interacts with α-cell GHB receptors, thus mediating the suppressive effect of glucose on glucagon release. We also identified glycine, acting via α-cell glycine receptors, as the predominant amino acid stimulator of glucagon release. The results suggest that glycine and GHB provide a counterbalancing receptor-based mechanism for controlling α-cell secretory responses to metabolic fuels. PMID:23266825

  16. Hormonal modulation of food intake in response to low leptin levels induced by hypergravity

    NASA Technical Reports Server (NTRS)

    Moran, M. M.; Stein, T. P.; Wade, C. E.

    2001-01-01

    A loss in fat mass is a common response to centrifugation and it results in low circulating leptin concentrations. However, rats adapted to hypergravity are euphagic. The focus of this study was to examine leptin and other peripheral signals of energy balance in the presence of a hypergravity-induced loss of fat mass and euphagia. Male Sprague-Dawley rats were centrifuged for 14 days at gravity levels of 1.25, 1.5, or 2 G, or they remained stationary at 1 G. Urinary catecholamines, urinary corticosterone, food intake, and body mass were measured on Days 11 to 14. Plasma hormones and epididymal fat pad mass were measured on Day 14. Mean body mass of the 1.25, 1.5, and 2 G groups were significantly (P < 0.05) lower than controls, and no differences were found in food intake (g/day/100 g body mass) between the hypergravity groups and controls. Epididymal fat mass was 14%, 14%, and 21% lower than controls in the 1.25, 1.5, and 2.0 G groups, respectively. Plasma leptin was significantly reduced from controls by 46%, 45%, and 65% in the 1.25, 1.5, and 2 G groups, respectively. Plasma insulin was significantly lower in the 1.25, 1.5, and 2.0 G groups than controls by 35%, 38%, and 33%. No differences were found between controls and hypergravity groups in urinary corticosterone. Mean urinary epinephrine was significantly higher in the 1.5 and 2.0 G groups than in controls. Mean urinary norepinephrine was significantly higher in the 1.25, 1.5 and 2.0 G groups than in controls. Significant correlations were found between G load and body mass, fat mass, leptin, urinary epinephrine, and norepinephrine. During hypergravity exposure, maintenance of food intake is the result of a complex relationship between multiple pathways, which abates the importance of leptin as a primary signal.

  17. Rapid Weight Loss Elicits Harmful Biochemical and Hormonal Responses in Mixed Martial Arts Athletes.

    PubMed

    Coswig, Victor Silveira; Fukuda, David Hideyoshi; Del Vecchio, Fabrício Boscolo

    2015-10-01

    The purpose of this study was to compare biochemical and hormonal responses between mixed martial arts (MMA) competitors with minimal prefight weight loss and those undergoing rapid weight loss (RWL). Blood samples were taken from 17 MMA athletes (Mean± SD; age: 27.4 ±5.3yr; body mass: 76.2 ± 12.4kg; height: 1.71 ± 0.05m and training experience: 39.4 ± 25 months) before and after each match, according to the official events rules. The no rapid weight loss (NWL, n = 12) group weighed in on the day of the event (~30 min prior fight) and athletes declared not having used RWL strategies, while the RWL group (n = 5) weighed in 24 hr before the event and the athletes claimed to have lost 7.4 ± 1.1kg, approximately 10% of their body mass in the week preceding the event. Results showed significant (p < .05) increases following fights, regardless of group, in lactate, glucose, lactate dehydrogenase (LDH), creatinine, and cortisol for all athletes. With regard to group differences, NWL had significantly (p < .05) greater creatinine levels (Mean± SD; pre to post) (NWL= 101.6 ± 15-142.3 ± 22.9μmol/L and RWL= 68.9 ± 10.6-79.5 ± 15.9μmol/L), while RWL had higher LDH (median [interquartile range]; pre to post) (NWL= 211.5[183-236] to 231[203-258]U/L and RWL= 390[370.5-443.5] to 488[463.5-540.5]U/L) and AST (NWL= 30[22-37] to 32[22-41]U/L and 39[32.5-76.5] to 72[38.5-112.5] U/L) values (NWL versus RWL, p < .05). Post hoc analysis showed that AST significantly increased in only the RWL group, while creatinine increased in only the NWL group. The practice of rapid weight loss showed a negative impact on energy availability and increased both muscle damage markers and catabolic expression in MMA fighters. PMID:25811230

  18. Final heights of boys with normal growth hormone responses to provocative tests following priming.

    PubMed

    Gonc, E Nazli; Kandemir, Nurgun; Ozon, Alev; Alikasifoglu, Ayfer

    2008-10-01

    Priming with sex steroids prior to growth hormone (GH) stimulation tests for the diagnosis of GH deficiency is still debatable. We analyzed the auxological data of boys with growth retardation who had normal GH responses to stimulation tests only after priming to establish the validity of priming in the diagnosis of GH deficiency. We also analyzed the effect of different protocols for priming and their efficiency in the diagnosis of GH deficiency. Fifty boys with growth retardation who failed to respond to unprimed GH stimulation tests but responded normally to primed tests were included in the study. Thirty-one of 50 boys responded to GH stimulation tests after single low dose testosterone, 11/50 boys after single conventional dose, and 8/50 boys with multiple-dose testosterone. The study group was followed till final height; height velocity, final height and height SDS were compared to parental and mid-parental heights to determine whether or not the children achieved their height potential. Mean final height SDS of the study group (-1.27 +/- 0.72 SDS) was similar to mid-parental (-1.38 +/- 0.72 SDS) (p = 0.249) and maternal height SDS (-1.26 +/- 1.05 SDS) (p = 0.941), whereas it was greater than the paternal height SDS (-1.7 +/- 0.86) (p = 0.001). The final height SDS of the study group was correlated to maternal, paternal and mid-parental height SDS. Height velocity after the test was greater than the previous height velocity. Final height SDS of the boys who responded to the GH stimulation tests with different priming protocols were compared and found to be similar. Normal responders in primed GH tests grow normally to their target height, suggesting that priming might be a valuable method in the assessment of GH status. Use of priming in the GH stimulation tests of peripubertal boys with decreased growth rate may help avoid unnecessary GH therapy. Multiple-dose testing might exclude GHD in a patient population who failed to respond to a single dose of

  19. Steer responses to feeding soybean hulls and steroid hormone implantation on toxic tall fescue pasture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yearling steers were grazed on endophyte-infected ‘Kentucky-31’ tall fescue (Lolium arundinaceum) pastures for 77 days in 2007 and for 86 days in 2008 to evaluate effects of feeding pelleted soybean hulls (PSBH) and steroid hormone implants (SHI) on steer performance and physiology. Steers were str...

  20. The Nature of Compensatory Response to Low Thyroid Hormone in Developing Brain.

    EPA Science Inventory

    Abstract Thyroid hormone is essential for normal brain development, but the degree to which the developing brain is sensitive to small perturbations in serum thyroxin is not clear. An important concept related to this is that the developing brain possesses potent mechanisms to co...

  1. Bovine acute-phase response following different doses of corticotrophin-releasing hormone challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fourteen weaned Angus steers (BW = 191 ± 2.1 kg, age = 167 ± 4.7 d) fitted with an indwelling jugular catheter and a rectal temperature (RT) monitoring device were ranked by BW and assigned to receive 1 of 3 treatments (i.v.): 1) 0.1 ug of bovine corticotrophin-release hormone (CRH)/kg of BW (CRH1; ...

  2. A Historical Perspective on the Identification of Cell Types in Pancreatic Islets of Langerhans by Staining and Histochemical Techniques.

    PubMed

    Baskin, Denis G

    2015-08-01

    Before the middle of the previous century, cell types of the pancreatic islets of Langerhans were identified primarily on the basis of their color reactions with histological dyes. At that time, the chemical basis for the staining properties of islet cells in relation to the identity, chemistry and structure of their hormones was not fully understood. Nevertheless, the definitive islet cell types that secrete glucagon, insulin, and somatostatin (A, B, and D cells, respectively) could reliably be differentiated from each other with staining protocols that involved variations of one or more tinctorial techniques, such as the Mallory-Heidenhain azan trichrome, chromium hematoxylin and phloxine, aldehyde fuchsin, and silver impregnation methods, which were popularly used until supplanted by immunohistochemical techniques. Before antibody-based staining methods, the most bona fide histochemical techniques for the identification of islet B cells were based on the detection of sulfhydryl and disulfide groups of insulin. The application of the classical islet tinctorial staining methods for pathophysiological studies and physiological experiments was fundamental to our understanding of islet architecture and the physiological roles of A and B cells in glucose regulation and diabetes. PMID:26216133

  3. A Historical Perspective on the Identification of Cell Types in Pancreatic Islets of Langerhans by Staining and Histochemical Techniques

    PubMed Central

    2015-01-01

    Before the middle of the previous century, cell types of the pancreatic islets of Langerhans were identified primarily on the basis of their color reactions with histological dyes. At that time, the chemical basis for the staining properties of islet cells in relation to the identity, chemistry and structure of their hormones was not fully understood. Nevertheless, the definitive islet cell types that secrete glucagon, insulin, and somatostatin (A, B, and D cells, respectively) could reliably be differentiated from each other with staining protocols that involved variations of one or more tinctorial techniques, such as the Mallory-Heidenhain azan trichrome, chromium hematoxylin and phloxine, aldehyde fuchsin, and silver impregnation methods, which were popularly used until supplanted by immunohistochemical techniques. Before antibody-based staining methods, the most bona fide histochemical techniques for the identification of islet B cells were based on the detection of sulfhydryl and disulfide groups of insulin. The application of the classical islet tinctorial staining methods for pathophysiological studies and physiological experiments was fundamental to our understanding of islet architecture and the physiological roles of A and B cells in glucose regulation and diabetes. PMID:26216133

  4. A second glucagon in the pancreatic islets of the daddy sculpin Cottus scorpius.

    PubMed

    Cutfield, S M; Cutfield, J F

    1993-09-01

    The peptide hormone glucagon has been isolated from the islet tissue (Brockmann bodies) of the teleost Cottus scorpius (daddy sculpin) and sequenced. The sequence is HSEGTSNDYSKYLEDRKAQDFVQWLMNN differing at four positions from the glucagon found earlier in the same species by Conlon and coworkers (1987b, Eur. J. Biochem, 164, 117-122). Thus sculpin, in common with anglerfish, possesses two distinct glucagons. Comparative sequence data are presented as a phylogenetic tree. PMID:8224771

  5. Development of the islets, exocrine pancreas, and related ducts in the Nile tilapia, Oreochromis niloticus (Pisces: Cichlidae).

    PubMed

    Morrison, Carol M; Pohajdak, Bill; Tam, Janet; Wright, James R

    2004-09-01

    Pancreatic development and the relationship of the islets with the pancreatic, hepatic, and bile ducts were studied in the Nile tilapia, Oreochromis niloticus, from hatching to the onset of maturity at 7 months. The number of islets formed during development was counted, using either serial sections or dithizone staining of isolated islets. There was a general increase in islet number with both age and size. Tilapia housed in individual tanks grew more quickly and had more islets than siblings of the same age left in crowded conditions. The pancreas is a compact organ in early development, and at 1 day posthatch (dph) a single principal islet, positive for all hormones tested (insulin, SST-14, SST-28, glucagon, and PYY), is partially surrounded by exocrine pancreas. However, the exocrine pancreas becomes more disseminated in older fish, following blood vessels along the mesenteries and entering the liver to form a hepatopancreas. The epithelium of the pancreatic duct system from the intercalated ducts to the main duct entering the duodenum was positive for glucagon and SST-14 in 8 and 16 dph tilapia. Individual insulin-immunopositive cells were found in one specimen. At this early stage in development, therefore, the pancreatic duct epithelial cells appear to be pluripotent and may give rise to the small islets found near the pancreatic ducts in 16-37 dph tilapia. Glucagon, SST-14, and some PPY-positive enteroendocrine cells were present in the intestine of the 8 dph larva and in the first part of the intestine of the 16 dph juvenile. Glucagon and SST-14-positive inclusions were found in the apical cytoplasm of the mid-gut epithelium of the 16 dph tilapia. These hormones may have been absorbed from the gut lumen, since they are produced in both the pancreatic ducts and the enteroendocrine cells. At least three hepatic ducts join the cystic duct to form the bile duct, which runs alongside the pancreatic duct to the duodenum. PMID:15281064

  6. Influence of Spinal and General Anesthesia on the Metabolic, Hormonal, and Hemodynamic Response in Elective Surgical Patients

    PubMed Central

    Milosavljevic, Snezana B.; Pavlovic, Aleksandar P.; Trpkovic, Sladjana V.; Ilić, Aleksandra N.; Sekulic, Ana D.

    2014-01-01

    Background The aim of the study was to determine the significance of spinal anesthesia in the suppression of the metabolic, hormonal, and hemodynamic response to surgical stress in elective surgical patients compared to general anesthesia. Material/Methods The study was clinical, prospective, and controlled and it involved 2 groups of patients (the spinal and the general anesthesia group) who underwent the same surgery. We monitored the metabolic and hormonal response to perioperative stress based on serum cortisol level and glycemia. We also examined how the different techniques of anesthesia affect these hemodynamic parameters: systolic arterial pressure (AP), diastolic AP, heart rate (HR), and arterial oxygen saturation (SpO2). These parameters were measured before induction on anesthesia (T1), 30 min after the surgical incisions (T2), 1 h postoperatively (T3) and 24 h after surgery (T4). Results Serum cortisol levels were significantly higher in the general anesthesia group compared to the spinal anesthesia group (p<0.01). Glycemia was significantly higher in the general anesthesia group (p<0.05). There was a statistically significant, positive correlation between serum cortisol levels and glycemia at all times observed (p<0.01). Systolic and diastolic AP did not differ significantly between the groups (p=0.191, p=0.101). The HR was significantly higher in the general anesthesia group (p<0.01). SpO2 values did not differ significantly between the groups (p=0.081). Conclusions Based on metabolic, hormonal, and hemodynamic responses, spinal anesthesia proved more effective than general anesthesia in suppressing stress response in elective surgical patients. PMID:25284266

  7. Metabolic assessment prior to total pancreatectomy and islet autotransplant: Utility, limitations, and potential

    PubMed Central

    Lundberg, Rachel; Beilman, Gregory J.; Dunn, Ty B.; Pruett, Timothy L.; Chinnakotla, Srinath C.; Radosevich, David M.; Robertson, R. Paul; Ptacek, Peggy; Balamurugan, A.N.; Wilhelm, Joshua J.; Hering, Bernhard J.; Sutherland, David E.R.; Moran, Antoinette; Bellin, Melena D.

    2013-01-01

    Islet autotransplant (IAT) may ameliorate post-surgical diabetes following total pancreatectomy (TP), but outcomes are dependent upon islet mass which is unknown prior to pancreatectomy. We evaluated whether pre-operative metabolic testing could predict islet isolation outcomes, and thus improve assessment of TPIAT candidates. We examined the relationship between measures from frequent sample IV glucose tolerance tests (FSIVGTT) and mixed meal tolerance tests (MMTT) and islet mass in 60 adult patients, with multivariate logistic regression modeling to identify predictors of islet mass ≥2500 IEQ/kg. The acute C-peptide response to glucose (ACRglu) and disposition index from FSIVGTT correlated modestly with the islet equivalents per kilogram body weight (IEQ/kg). Fasting and MMTT glucose levels and HbA1c correlated inversely with IEQ/kg (r values −0.33 to −0.40, p≤0.05). In multivariate logistic regression modeling, normal fasting glucose (<100 mg/dL) and stimulated C-peptide on MMTT ≥4 ng/mL were associated with greater odds of receiving an islet mass ≥2,500 IEQ/kg (OR 0.93 for fasting glucose, CI 0.87–1.0; OR 7.9 for C-peptide, CI 1.75–35.6). In conclusion, parameters obtained from FSIVGTT correlate modestly with islet isolation outcomes. Stimulated C-peptide ≥4 ng/mL on MMTT conveyed 8 times the odds of receiving ≥2,500 IEQ/kg, a threshold associated with reasonable metabolic control post-operatively. PMID:23924045

  8. Vascular endothelial growth factor coordinates islet innervation via vascular scaffolding

    PubMed Central

    Reinert, Rachel B.; Cai, Qing; Hong, Ji-Young; Plank, Jennifer L.; Aamodt, Kristie; Prasad, Nripesh; Aramandla, Radhika; Dai, Chunhua; Levy, Shawn E.; Pozzi, Ambra; Labosky, Patricia A.; Wright, Christopher V. E.; Brissova, Marcela; Powers, Alvin C.

    2014-01-01

    Neurovascular alignment is a common anatomical feature of organs, but the mechanisms leading to this arrangement are incompletely understood. Here, we show that vascular endothelial growth factor (VEGF) signaling profoundly affects both vascularization and innervation of the pancreatic islet. In mature islets, nerves are closely associated with capillaries, but the islet vascularization process during embryonic organogenesis significantly precedes islet innervation. Although a simple neuronal meshwork interconnects the developing islet clusters as they begin to form at E14.5, the substantial ingrowth of nerve fibers into islets occurs postnatally, when islet vascularization is already complete. Using genetic mouse models, we demonstrate that VEGF regulates islet innervation indirectly through its effects on intra-islet endothelial cells. Our data indicate that formation of a VEGF-directed, intra-islet vascular plexus is required for development of islet innervation, and that VEGF-induced islet hypervascularization leads to increased nerve fiber ingrowth. Transcriptome analysis of hypervascularized islets revealed an increased expression of extracellular matrix components and axon guidance molecules, with these transcripts being enriched in the islet-derived endothelial cell population. We propose a mechanism for coordinated neurovascular development within pancreatic islets, in which endocrine cell-derived VEGF directs the patterning of intra-islet capillaries during embryogenesis, forming a scaffold for the postnatal ingrowth of essential autonomic nerve fibers. PMID:24574008

  9. The fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model

    NASA Astrophysics Data System (ADS)

    Jo, Junghyo; Hörnblad, Andreas; Kilimnik, German; Hara, Manami; Ahlgren, Ulf; Periwal, Vipul

    2013-06-01

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, has not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension of 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with a fractal dimension of 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas.

  10. Hair Follicle Dermal Sheath Derived Cells Improve Islet Allograft Survival without Systemic Immunosuppression

    PubMed Central

    Wang, Xiaojie; Hao, Jianqiang; Leung, Gigi; Breitkopf, Trisia; Wang, Eddy; Kwong, Nicole; Akhoundsadegh, Noushin; Warnock, Garth L.; Shapiro, Jerry; McElwee, Kevin J.

    2015-01-01

    Immunosuppressive drugs successfully prevent rejection of islet allografts in the treatment of type I diabetes. However, the drugs also suppress systemic immunity increasing the risk of opportunistic infection and cancer development in allograft recipients. In this study, we investigated a new treatment for autoimmune diabetes using naturally immune privileged, hair follicle derived, autologous cells to provide localized immune protection of islet allotransplants. Islets from Balb/c mouse donors were cotransplanted with syngeneic hair follicle dermal sheath cup cells (DSCC, group 1) or fibroblasts (FB, group 2) under the kidney capsule of immune-competent, streptozotocin induced, diabetic C57BL/6 recipients. Group 1 allografts survived significantly longer than group 2 (32.2 ± 12.2 versus 14.1 ± 3.3 days, P < 0.001) without administration of any systemic immunosuppressive agents. DSCC reduced T cell activation in the renal lymph node, prevented graft infiltrates, modulated inflammatory chemokine and cytokine profiles, and preserved better beta cell function in the islet allografts, but no systemic immunosuppression was observed. In summary, DSCC prolong islet allograft survival without systemic immunosuppression by local modulation of alloimmune responses, enhancing of beta cell survival, and promoting of graft revascularization. This novel finding demonstrates the capacity of easily accessible hair follicle cells to be used as local immunosuppression agents in islet transplantation. PMID:26000314

  11. PAX4 Defines an Expandable β-Cell Subpopulation in the Adult Pancreatic Islet

    PubMed Central

    Lorenzo, Petra I.; Fuente-Martín, Esther; Brun, Thierry; Cobo-Vuilleumier, Nadia; Jimenez-Moreno, Carmen María; G. Herrera Gomez, Irene; López Noriega, Livia; Mellado-Gil, José Manuel; Martin-Montalvo, Alejandro; Soria, Bernat; Gauthier, Benoit R.

    2015-01-01

    PAX4 is a key regulator of pancreatic islet development whilst in adult acute overexpression protects β-cells against stress-induced apoptosis and stimulates proliferation. Nonetheless, sustained PAX4 expression promotes β-cell dedifferentiation and hyperglycemia, mimicking β-cell failure in diabetic patients. Herein, we study mechanisms that allow stringent PAX4 regulation endowing favorable β-cell adaptation in response to changing environment without loss of identity. To this end, PAX4 expression was monitored using a mouse bearing the enhanced green fluorescent protein (GFP) and cre recombinase construct under the control of the islet specific pax4 promoter. GFP was detected in 30% of islet cells predominantly composed of PAX4-enriched β-cells that responded to glucose-induced insulin secretion. Lineage tracing demonstrated that all islet cells were derived from PAX4+ progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication. However, this GFP+ subpopulation expanded during pregnancy, a state of active β-cell replication. Accordingly, enhanced proliferation was exclusively detected in GFP+ cells consistent with cell cycle genes being stimulated in PAX4-overexpressing islets. Under stress conditions, GFP+ cells were more resistant to apoptosis than their GFP- counterparts. Our data suggest PAX4 defines an expandable β-cell sub population within adult islets. PMID:26503027

  12. Fractal spatial distribution of pancreatic islets in three dimensions: a self-avoiding growth model

    PubMed Central

    Jo, Junghyo; Hörnblad, Andreas; Kilimnik, German; Hara, Manami; Ahlgren, Ulf; Periwal, Vipul

    2013-01-01

    The islets of Langerhans, responsible for controlling blood glucose levels, are dispersed within the pancreas. A universal power law governing the fractal spatial distribution of islets in two-dimensional pancreatic sections has been reported. However, the fractal geometry in the actual three-dimensional pancreas volume, and the developmental process that gives rise to such a self-similar structure, have not been investigated. Here, we examined the three-dimensional spatial distribution of islets in intact mouse pancreata using optical projection tomography and found a power law with a fractal dimension, 2.1. Furthermore, based on two-dimensional pancreatic sections of human autopsies, we found that the distribution of human islets also follows a universal power law with fractal dimension 1.5 in adult pancreata, which agrees with the value previously reported in smaller mammalian pancreas sections. Finally, we developed a self-avoiding growth model for the development of the islet distribution and found that the fractal nature of the spatial islet distribution may be associated with the self-avoidance in the branching process of vascularization in the pancreas. PMID:23629025

  13. Use of perfluorocarbon nanoparticles for non-invasive multimodal cell tracking of human pancreatic islets

    PubMed Central

    Barnett, Brad P.; Ruiz-Cabello, Jesus; Hota, Partha; Ouwerkerk, Ronald; Shamblott, Michael J.; Lauzon, Cal; Walczak, Piotr; Gilson, Wesley D.; Chacko, Vadappuram P.; Kraitchman, Dara L.; Arepally, Aravind; Bulte, Jeff W. M.

    2011-01-01

    In vivo imaging of engraftment and immunorejection of transplanted islets is critical for further clinical development, with 1H MR imaging of superparamagnetic iron oxide-labeled cells being the current premier modality. Using perfluorocarbon nanoparticles, we present here a strategy for non-invasive imaging of cells using other modalities. To this end, human cadaveric islets were labeled with rhodamine-perfluorooctylbromide (PFOB) nanoparticles, rhodamine-perfluoropolyether (PFPE) nanoparticles or Feridex® as control and tested in vitro for cell viability and c-peptide secretion for 1 week. 19F MRI, computed tomography (CT) and ultrasound (US) imaging was performed on labeled cell phantoms and on cells following transplantation beneath the kidney capsule of mice and rabbits. PFOB and PFPE-labeling did not reduce human islet viability or glucose responsiveness as compared with unlabeled cells or SPIO-labeled cells. PFOB- and PFPE-labeled islets were effectively fluorinated for visualization by 19F MRI. PFOB-labeled islets were acoustically reflective for detection by US imaging and became sufficiently brominated to become radiopaque allowing visualization with CT. Thus, perfluorocarbon nanoparticles are multimodal cellular contrast agents that may find applications in real-time targeted delivery and imaging of transplanted human islets or other cells in a clinically applicable manner using MRI, US or CT imaging. PMID:21861285

  14. Hormonal responses and test meal intake among obese teenagers before and after laparoscopic adjustable gastric banding123

    PubMed Central

    Devlin, Michael J; Schebendach, Janet; Tanofsky-Kraff, Marian; Zimmerli, Ellen; Korner, Judith; Yanovski, Jack A; Zitsman, Jeffrey L; Walsh, B Timothy

    2013-01-01

    Background: Relatively little is known about changes in eating behavior or hormonal responses to food after bariatric surgery in adolescents. Objective: This study compared eating behavior and hormones among adolescents in a bariatric surgery program with those in nonoverweight control adolescents and evaluated changes before and after laparoscopic adjustable gastric banding (LAGB). Design: Fasting leptin, peptide YY (PYY), and ghrelin concentrations were obtained, and postprandial ghrelin and PYY area under the curve (AUC) were assessed after a single-item breakfast. Intake from an ad libitum lunchtime multi-item meal was measured. Results: Compared with controls (n = 9), all presurgical candidates (n = 20) had significantly greater fasting leptin, lower fasting ghrelin, and lower AUC ghrelin but similar PYY and AUC PYY. Preoperative candidates did not differ from controls in total energy consumed during the test meal. Postoperatively, among the 11 participants with data both before and after surgery, BMI (in kg/m2) decreased by 3.5 (P < 0.001), significantly less energy was consumed in the test meal, and a smaller number of foods were selected. AUC ghrelin and PYY did not significantly change before or after LAGB. Conclusions: Few significant short-term changes were observed in appetitive hormones after LAGB. It is unclear whether objective measures of eating behavior will prove useful in evaluating the impact of bariatric surgery on outcomes. This trial was registered at clinicaltrials.gov as CT00764127. PMID:23985807

  15. Isolation of hormone responsive uterine stromal cells: an in vitro model for stromal cell proliferation and differentiation.

    PubMed

    Rider, Virginia

    2006-01-01

    The female sex hormones estrogen and progesterone stimulate proliferation and differentiation of human and rodent uterine cells. The purpose of this chapter is to provide a method for isolating hormone-responsive rat uterine stromal cell lines that can be used to study steroid control of the cell cycle. Uteri from ovariectomized rats are differentially digested with trypsin to separate epithelial and stromal cells. The stromal cells are cultured in a standard growth medium containing 10% fetal bovine serum. After several passages, the purity of the stromal cell lines is determined using immunocytochemistry. Cell proliferation is studied by culturing the stromal cells in serum-free medium containing sex steroids and other mitogens. Cell cycle progression is assessed by flow cytometry, 3H-thymidine and BrdU incorporation, whereas proliferation is monitored using the MTT assay. Cell cycle regulators are visualized by Northern and Western blotting whereas cyclin-cyclin-dependent kinase activity is monitored using immune complex kinase assays. Uterine stromal cell lines isolated using the methods reported in this chapter provide a suitable model system to investigate the signal transduction events that stimulate hormone-dependent control of the cell cycle. PMID:16251733

  16. The response of thyroid hormones, biochemical and enzymological biomarkers to pyrene exposure in common carp (Cyprinus carpio).

    PubMed

    Shirdel, Iman; Kalbassi, Mohammad Reza; Shokri, Milad; Olyaei, Roya; Sharifpour, Issa

    2016-08-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are discharged into aquatic environments through anthropogenic activities mainly industrial and municipal effluents. There is little information on the adverse effects of pyrene, a member of the PAH family which is classified as a priority pollutant by the USEPA, on fish biochemical and physiological endpoints, particularly thyroid hormones. The present study investigated the effects of subacute semi-static pyrene exposure on biochemical, enzymological and ionoregulatory responses as well as thyroid hormones in common carp (Cyprinus carpio). The fish (140±10g, 1(+) year) were exposed to 10, 50 and 100µg/l nominal concentrations of pyrene for 35 days. The results revealed that pyrene at these concentrations significantly altered plasma levels of glucose, cholesterol, triglyceride, total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP). Moreover, plasma thyroid hormones (T3 and T4) were significantly decreased in fish exposed to pyrene. In contrast, plasma electrolytes (sodium, potassium and calcium) levels remained statistically unchanged after exposure to the various pyrene concentrations. In conclusion, the studied biomarkers may be used as monitoring tools to evaluate pyrene toxicity. Pyrene induced diverse effects on the physiological endpoints of common carp, thus this chemical should be considered in toxicity studies concerning PAHs. Furthermore, this study confirmed that there was an interaction between pyrene and the thyroid system in fish. Therefore, the thyroid system may be used to assess the impact of pyrene on fish. PMID:27123973

  17. A screening assay for thyroid hormone signaling disruption based on thyroid hormone-response gene expression analysis in the frog Pelophylax nigromaculatus.

    PubMed

    Zhang, Yinfeng; Li, Yuanyuan; Qin, Zhanfen; Wang, Huili; Li, Jianzhong

    2015-08-01

    Amphibian metamorphosis provides a wonderful model to study the thyroid hormone (TH) signaling disrupting activity of environmental chemicals, with Xenopus laevis as the most commonly used species. This study aimed to establish a rapid and sensitive screening assay based on TH-response gene expression analysis using Pelophylax nigromaculatus, a native frog species distributed widely in East Asia, especially in China. To achieve this, five candidate TH-response genes that were sensitive to T3 induction were chosen as molecular markers, and T3 induction was determined as 0.2 nmol/L T3 exposure for 48 hr. The developed assay can detect the agonistic activity of T3 with a lowest observed effective concentration of 0.001 nmol/L and EC50 at around 0.118-1.229 nmol/L, exhibiting comparable or higher sensitivity than previously reported assays. We further validated the efficiency of the developed assay by detecting the TH signaling disrupting activity of tetrabromobisphenol A (TBBPA), a known TH signaling disruptor. In accordance with previous reports, we found a weak TH agonistic activity for TBBPA in the absence of T3, whereas a TH antagonistic activity was found for TBBPA at higher concentrations in the presence of T3, showing that the P. nigromaculatus assay is effective for detecting TH signaling disrupting activity. Importantly, we observed non-monotonic dose-dependent disrupting activity of TBBPA in the presence of T3, which is difficult to detect with in vitro reporter gene assays. Overall, the developed P. nigromaculatus assay can be used to screen TH signaling disrupting activity of environmental chemicals with high sensitivity. PMID:26257357

  18. Time-course of prednisone effects on hormonal and inflammatory responses at rest and during resistance exercise.

    PubMed

    Collomp, K; Zorgati, H; Cottin, F; Do, M-C; Labsy, Z; Gagey, O; Lasne, F; Prieur, F; Collomp, R

    2015-06-01

    Glucocorticoids are among the most commonly used drugs. They are widely administered for acute and chronic musculoskeletal pain, as well as for several other pain syndromes, although their therapeutic use is sometimes diverted for doping purposes. Their time-course effects on hormonal and inflammatory responses nevertheless remain poorly understood, both at rest and during exercise. We therefore studied the alterations induced by 1 week of prednisone treatment (60 mg daily) in recreationally trained male athletes after 2 days (i. e., acute) and 7 days (i. e., short-term). Hormonal (i. e., DHEA, DHEA-S, aldosterone, and testosterone) and pro- and anti-inflammatory markers (i. e., IL-6, IL-10, and IL-1β) were investigated at rest and after resistance exercise. A significant decrease in DHEA and DHEA-S (p<0.01) without change in the DHEA/DHEA-S ratio, aldosterone, or testosterone was demonstrated after acute prednisone intake. A significant increment in IL-10 and a significant decrement in IL-6 (p<0.05) were also observed with prednisone both at rest and during exercise, without significant change in IL-1β. Continued prednisone treatment led to another significant decrease in both DHEA and DHEA-S (p<0.05), whereas no change in the inflammatory markers was observed between days 2 and 7. Our data demonstrate that the anti-inflammatory effects of prednisone were maximal and stable from the beginning of treatment, both in rest and exercise conditions. However, hormonal concentrations continued to decline during short-term intake. Further studies are needed to determine the effects of hormonal time-course alterations with longer glucocorticoid treatment and the clinical consequences. PMID:25611207

  19. Asperlicin antagonizes stimulatory effects of cholecystokinin on isolated islets

    SciTech Connect

    Zawalich, W.S.; Diaz, V.A.

    1987-03-01

    Asperlicin, a product derived from the fungus Aspergillus alliaceus, antagonized the multiple stimulatory effects of cholecystokinin (CCK-8S) on isolated islets. At a level of 10 uM, asperlicin completely inhibited insulin release in response to 25 nM CCK-8S. Increasing the level of CCK-8S to 100 nM partially restored a secretory response, while an even greater insulin stimulatory effect was noted with 500 nM CCK-8S. The inhibitory effect of asperlicin on CCK-8S-induced release was reversible. Asperlicin exposure had no effect on glucose or glyceraldehyde-induced secretion. Asperlicin reduced, in parallel with secretion, the increase in /sup 3/H efflux from (/sup 3/H) inositol prelabeled islets usually noted with CCK-8S addition. Asperlicin did not influence the small glucose-stimulated increase in /sup 3/H efflux. The results support the notion that asperlicin is a specific and potent antagonist of the multiple stimulatory effects of CCK-8S on islet tissue.

  20. Effect of Time of Day on Performance, Hormonal and Metabolic Response during a 1000-M Cycling Time Trial

    PubMed Central

    Fernandes, Alan Lins; Lopes-Silva, João Paulo; Bertuzzi, Rômulo; Casarini, Dulce Elena; Arita, Danielle Yuri; Bishop, David John; Lima-Silva, Adriano Eduardo

    2014-01-01

    The aim of this study was to determine the effect of time of day on performance, pacing, and hormonal and metabolic responses during a 1000-m cycling time-trial. Nine male, recreational cyclists visited the laboratory four times. During the 1st visit the participants performed an incremental test and during the 2nd visit they performed a 1000-m cycling familiarization trial. On the 3rd and 4th visits, the participants performed a 1000-m TT at either 8 am or 6 pm, in randomized, repeated-measures, crossover design. The time to complete the time trial was lower in the evening than in the morning (88.2±8.7 versus 94.7±10.9 s, respectively, p<0.05), but there was no significant different in pacing. However, oxygen uptake and aerobic mechanical power output at 600 and 1000 m tended to be higher in the evening (p<0.07 and 0.09, respectively). There was also a main effect of time of day for insulin, cortisol, and total and free testosterone concentration, which were all higher in the morning (+60%, +26%, +31% and +22%, respectively, p<0.05). The growth hormone, was twofold higher in the evening (p<0.05). The plasma glucose was ∼11% lower in the morning (p<0.05). Glucagon, norepinephrine, epinephrine and lactate were similar for the morning and evening trials (p>0.05), but the norepinephrine response to the exercise was increased in the morning (+46%, p<0.05), and it was accompanied by a 5-fold increase in the response of glucose. Muscle recruitment, as measured by electromyography, was similar between morning and evening trials (p>0.05). Our findings suggest that performance was improved in the evening, and it was accompanied by an improved hormonal and metabolic milieu. PMID:25289885

  1. Physiologic responses following gonadotropin-releasing hormone immunization in intact male dogs.

    PubMed

    Donovan, C E; Greer, M; Kutzler, M A

    2012-12-01

    We investigated the use of a commercial gonadotropin-releasing hormone (GnRH) vaccine as a method of temporary and reversible immunocastration in intact male dogs. Four privately owned dogs were vaccinated twice at 4-week intervals. Blood samples were collected at 0, 4, 12 and 20 weeks following the initial vaccination. These samples were analysed for GnRH antibody titres, luteinizing hormone (LH) and testosterone concentrations. Scrotal measurements were made at the time of sample collection, and testicular volume was calculated using the formula of an ellipsoid. As a result of vaccination, dogs displayed an elevated GnRH antibody titre, decreased LH and testosterone concentrations and decreased testicular volume, which reversed by the end of the study period. Therefore, these results suggest that immunizing against GnRH may be a possible choice for temporary and reversible immunocastration. PMID:23279550

  2. Islet amyloid polypeptide inserts into phospholipid monolayers as monomer.

    PubMed

    Engel, Maarten F M; Yigittop, HaciAli; Elgersma, Ronald C; Rijkers, Dirk T S; Liskamp, Rob M J; de Kruijff, Ben; Höppener, Jo W M; Antoinette Killian, J

    2006-02-24

    Amyloid deposits in the pancreatic islets of Langerhans are thought to be a main factor responsible for death of the insulin-producing islet beta-cells in type 2 diabetes. It is hypothesized that beta-cell death is related to interaction of the 37 amino acid residue human islet amyloid polypeptide (hIAPP), the major constituent of islet amyloid, with cellular membranes. However, the mechanism of hIAPP-membrane interactions is largely unknown. Here, we study the nature and the molecular details of the initial step of hIAPP-membrane interactions by using the monolayer technique. It is shown that both freshly dissolved hIAPP and the non-amyloidogenic mouse IAPP (mIAPP) have a pronounced ability to insert into phospholipid monolayers, even at lipid packing conditions that exceed the conditions that occur in biological membranes. In contrast, the fibrillar form of hIAPP has lost the ability to insert. These results, combined with the observations that both the insertion kinetics and the dependence of insertion on the initial surface pressure are similar for freshly dissolved hIAPP and mIAPP, indicate that hIAPP inserts into phospholipid monolayers most likely as a monomer. In addition, our results suggest that the N-terminal part of hIAPP, which is nearly identical with that of mIAPP, is largely responsible for insertion. This is supported by e