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Sample records for growth hormone-releasing peptides

  1. Epidermal growth factor and growth hormone-releasing peptide-6: combined therapeutic approach in experimental stroke.

    PubMed

    García Del Barco-Herrera, Diana; Martínez, Nelvys Subirós; Coro-Antich, Rosa María; Machado, Jorge Martín; Alba, José Suárez; Salgueiro, Sandra Rodríguez; Acosta, Jorge Berlanga

    2013-01-01

    Stroke is the second cause of mortality worldwide, with a high incidence of disability in survivors. Promising candidate drugs have failed in stroke trials. Combined therapies are attractive strategies that simultaneously target different points of stroke pathophysiology. The aim of this work is to determine whether the combined effects of epidermal growth factor (EGF) and growth hormone-releasing peptide-6 (GHRP6) can attenuate clinical signs and pathology in an experimental stroke model. Brain global ischemia was generated in Mongolian gerbils by 15 minutes of carotid occlusion. After reperfusion, EGF, GHRP6 or EGF+GHRP6 were intraperitoneally administered. Clinical manifestations were monitored daily. Three days after reperfusion, animals were anesthetized and perfused with an ink solution. The anatomy of the Circle of Willis was characterized. Infarct volume and neuronal density were analyzed. EGF+GHRP6 co-administration reduced clinical manifestations and infarct volume and preserved neuronal density. No correlation was observed between the grade of anastomosis of the Circle of Willis and clinical manifestations in the animals receiving EGF+GHRP6, as opposed to the vehicle-treated gerbils. Co-treatment with EGF and GHRP6 affects both the clinical and pathological outcomes in a global brain ischemia model, suggesting a suitable therapeutic approach for the acute management of stroke.

  2. Growth hormone-releasing peptide-6 inhibits cerebellar cell death in aged rats.

    PubMed

    Pañeda, Covadonga; Arroba, Ana I; Frago, Laura M; Holm, Anne Mette; Rømer, John; Argente, Jesús; Chowen, Julie A

    2003-08-26

    Insulin-like growth factor (IGF)-I is essential for cerebellar granule neuron survival and a decline in IGF-I is implicated in various age-dependent processes. Here we show that IGF-I mRNA levels are decreased in the cerebellum of old rats compared with young rats and this was associated with increased cell death and activation of caspases 3 and 9. Growth hormone-releasing peptide (GHRP)-6, a synthetic ligand for the ghrelin receptor, increased IGF-I mRNA levels, decreased cell death and inhibited caspase 3 and 9 activation in the cerebellum of aged rats. These results suggest that increasing IGF-I expression in the cerebellum can decrease cell death in aged rats via inhibition of caspase 3 and 9 activation.

  3. Synthesis of Mono-PEGylated Growth Hormone Releasing Peptide-2 and Investigation of its Biological Activity.

    PubMed

    Hu, Xiaoyu; Xu, Beihua; Zhou, Ziniu

    2015-10-01

    The purpose of this study was to investigate an efficient synthetic route to the mono-PEGylated growth hormone releasing peptide-2 (GHRP-2) and its biological activity in vivo. The commercially available key PEGylating reagent, mPEG-NHS ester, was successfully utilized to the synthesis of mono-PEGylated GHRP-2, during which the PEGylation profiles of GHRP-2 were monitored by high-performance liquid chromatography (HPLC). The product was purified by cation exchange chromatography, and its biological activity was conducted in rats. The desired mono-PEGylated GHRP-2 as the major product was readily obtained in anhydrous aprotic solvent, such as dimethyl formamide (DMF) and dimethylsulfoxide (DMSO), when the molar ratio of mPEG-NHS ester to GHRP-2 was fixed to be 0.8:1. The products were characterized by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. The evaluation of the biological activity for the products showed that the mono-PEGylated GHRP-2 gave a more stable activity than GHRP-2, suggesting that PEGylation led to the increase in the half-life of GHRP-2 in plasma without greatly impairing the biological activity. PEGylation of the GHRP-2 is a good choice for the development of the GHRP-2 applications.

  4. Identification of the growth-hormone-releasing peptide-2 (GHRP-2) in a nutritional supplement.

    PubMed

    Thomas, Andreas; Kohler, Maxie; Mester, Joachim; Geyer, Hans; Schänzer, Wilhelm; Petrou, Michael; Thevis, Mario

    2010-03-01

    Black market products of a pharmaceutical nature and nutritional supplements have received substantial and increasing attention because of potential performance enhancement in elite and non-professional sports. In addition, improved general health is claimed for non-competing individuals. The risks and foreseeable dangers of the uncontrolled use of highly potent and non-approved pharmaceutical compounds in healthy individuals are of considerable concern. In the present case report, the emerging drug candidate GHRP-2 with verified growth-hormone-releasing properties was identified and quantified in tablets offered as an over-the-counter nutritional supplement. The impact of this orally active peptide on the hGH/IGF-axis has been established for several years and its illicit use in elite sports has been assumed. As a releasing factor for hGH, GHRP-2 belongs to the list of substances prohibited by the World Anti-Doping Agency (WADA). Unfortunately, to date there is no routinely performed assay for the determination of these peptides potentially occurring in biological fluids of competing athletes, but the present data will facilitate the implementation by providing principle analytical information on liquid chromatographic and mass spectrometric behaviour. Qualitative identification of the target analyte after extraction from the tablet matrix was performed by high resolution/high accuracy mass spectrometry after liquid chromatographic separation under consideration of the accurate masses and the ratios of the protonated molecules and their fragment ions derived from their collisionally induced dissociation. Quantitative results were obtained by means of liquid chromatography coupled to a triple quadrupole mass spectrometer and linear regression using an external calibration curve (with GHRP-2 reference compound) adjusted via internal standard (Hexarelin). Hereby, the content of GHRP-2 was determined with approximately 50 µg per tablet.

  5. In vitro release study of mono-PEGylated growth hormone-releasing peptide-6 from PLGA microspheres.

    PubMed

    Park, Eun Ji; Na, Dong Hee; Lee, Kang Choon

    2007-10-01

    The purpose of this study was to investigate in vitro release property of mono-PEGylated growth hormone-releasing peptide-6 (GHRP-6) microspheres. The microspheres encapsulating native GHRP-6 or mono-PEG-GHRP-6 were prepared using the single oil-in-water emulsion solvent evaporation method. In vitro release study was performed in 0.1M phosphate buffer, pH 7.4, containing 0.02% Tween 80 and sodium azide at 37 or 55 degrees C. The mono-PEG-GHRP-6 microspheres showed a lower initial burst compared with native GHRP-6 microspheres and zero-order release profile for a 1-month period. The release period was dependent on the PEG size attached to the GHRP-6 with more rapid drug release being observed with the smaller PEG size. This study suggests that PEGylated peptide has good potential as a source for a sustained release microsphere delivery system.

  6. Effects of ghrelin, growth hormone-releasing peptide-6, and growth hormone-releasing hormone on growth hormone, adrenocorticotropic hormone, and cortisol release in type 1 diabetes mellitus.

    PubMed

    de Sá, Larissa Bianca Paiva Cunha; Nascif, Sergio Oliva; Correa-Silva, Silvia Regina; Molica, Patricia; Vieira, José Gilberto Henriques; Dib, Sergio Atala; Lengyel, Ana-Maria Judith

    2010-10-01

    In type 1 diabetes mellitus (T1DM), growth hormone (GH) responses to provocative stimuli are normal or exaggerated, whereas the hypothalamic-pituitary-adrenal axis has been less studied. Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6). Ghrelin's effects in patients with T1DM have not been evaluated. We therefore studied GH, ACTH, and cortisol responses to ghrelin and GHRP-6 in 9 patients with T1DM and 9 control subjects. The GH-releasing hormone (GHRH)-induced GH release was also evaluated. Mean fasting GH levels (micrograms per liter) were higher in T1DM (3.5 ± 1.2) than in controls (0.6 ± 0.3). In both groups, ghrelin-induced GH release was higher than that after GHRP-6 and GHRH. When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls. There was a trend (P = .055) to higher mean basal cortisol values (micrograms per deciliter) in T1DM (11.7 ± 1.5) compared with controls (8.2 ± 0.8). No significant differences were seen in ΔAUC cortisol values in both groups after ghrelin and GHRP-6. Mean fasting ACTH values were similar in T1DM and controls. No differences were seen in ΔAUC ACTH levels in both groups after ghrelin and GHRP-6. In summary, patients with T1DM have normal GH responsiveness to ghrelin, GHRP-6, and GHRH. The ACTH and cortisol release after ghrelin and GHRP-6 is also similar to controls. Our results suggest that chronic hyperglycemia of T1DM does not interfere with GH-, ACTH-, and cortisol-releasing mechanisms stimulated by these peptides.

  7. Neuroprotective effect of epidermal growth factor plus growth hormone-releasing peptide-6 resembles hypothermia in experimental stroke.

    PubMed

    Subirós, N; Pérez-Saad, H; Aldana, L; Gibson, C L; Borgnakke, W S; Garcia-Del-Barco, D

    2016-11-01

    Combined therapy with epidermal growth factor (EGF) and growth hormone-releasing peptide 6 (GHRP-6) in stroke models has accumulated evidence of neuroprotective effects from several studies, but needs further support before clinical translation. Comparing EGF + GHRP-6 to hypothermia, a gold neuroprotection standard, may contribute to this purpose. The aims of this study were to compare the neuroprotective effects of a combined therapy based on EGF + GHRP-6 with hypothermia in animal models of (a) global ischemia representing myocardial infarction and (b) focal brain ischemia representing ischemic stroke. (a) Global ischemia was induced in Mongolian gerbils by a 15-min occlusion of both carotid arteries, followed by reperfusion. (b) Focal brain ischemia was achieved by intracerebral injection of endothelin 1 in Wistar rats. In each experiment, three ischemic treatment groups - vehicle, EGF + GHRP-6, and hypothermia - were compared to each other and to a sham-operated control group. End points were survival, neurological scores, and infarct volume. (a) In global ischemia, neurological score at 48-72 h, infarct volume, and neuronal density of hippocampal CA1 zone in gerbils treated with EGF + GHRP-6 were similar to the hypothermia-treated group. (b) In focal ischemia, the neurologic score and infarct volume of rats receiving EGF + GHRP-6 were also similar to animals in the hypothermia group. With hypothermia being a good standard neuroprotectant reference, these results provide additional proof of principle for EGF and GHRP-6 co-administration as a potentially neuroprotective stroke therapy.

  8. Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation.

    PubMed

    Henninge, John; Pepaj, Milaim; Hullstein, Ingunn; Hemmersbach, Peter

    2010-01-01

    Several peptide drugs are being manufactured illicitly, and in some cases they are being made available to the public before entering or completing clinical trials. At the request of Norwegian police and customs authorities, unknown pharmaceutical preparations suspected to contain peptide drugs are regularly subjected to analysis. In 2009, an unknown pharmaceutical preparation was submitted for analysis by liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS). The preparation was found to contain a 29 amino acid peptide with a C-terminal amide function. Based on the interpretation of mass spectrometric data, an amino acid sequence was proposed. The sequence is consistent with a peptide currently marketed under the name CJC-1295. CJC-1295 is a releasing factor for growth hormone and is therefore considered a Prohibited Substance under Section S2 of the WADA Prohibited List. This substance has potential performance-enhancing effects, it is readily available, and there is reason to believe that it is being used within the bodybuilding community. Copyright © 2010 John Wiley & Sons, Ltd.

  9. Formation of acylated growth hormone-releasing peptide-6 by poly(lactide-co-glycolide) and its biological activity.

    PubMed

    Na, Dong Hee; Lee, Jeong Eun; Jang, Sun Woo; Lee, Kang Choon

    2007-06-08

    The purpose of this study was to investigate the formation of acylated impurity resulting from a chemical reaction between the growth hormone-releasing peptide-6 (GHRP-6) and poly(lactide-co-glycolide) (PLGA) and the effect of peptide acylation on the in vivo biological activity of GHRP-6. The peptide acylation pattern of GHRP-6 by hydrophilic PLGA polymers with different molecular weights was characterized by reversed-phase high-performance liquid chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Higher levels of acylated GHRP-6 were produced with the higher molecular weight PLGA, which might be due to the slower degradation rate of the polymer. The evaluation of the biological activity in rats showed that the acylated GHRP-6 had a much lower activity than the intact GHRP-6. This finding suggests that the acylation reaction would decrease the effectiveness of the GHRP-6 formulation such as PLGA microspheres. Therefore, a strategy for stabilizing the GHRP-6 will be necessary for the development of a successful formulation of PLGA microspheres.

  10. Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects

    PubMed Central

    Berlanga-Acosta, Jorge; Abreu-Cruz, Angel; Barco Herrera, Diana García-del; Mendoza-Marí, Yssel; Rodríguez-Ulloa, Arielis; García-Ojalvo, Ariana; Falcón-Cama, Viviana; Hernández-Bernal, Francisco; Beichen, Qu; Guillén-Nieto, Gerardo

    2017-01-01

    Background: Growth hormone-releasing peptides (GHRPs) constitute a group of small synthetic peptides that stimulate the growth hormone secretion and the downstream axis activity. Mounting evidences since the early 1980s delineated unexpected pharmacological cardioprotective and cytoprotective properties for the GHRPs. However, despite intense basic pharmacological research, alternatives to prevent cell and tissue demise before lethal insults have remained as an empty niche in the clinical armamentarium. Here, we have rigorously reviewed the investigational development of GHRPs and their clinical niching perspectives. Methodology: PubMed/MEDLINE databases, including original research and review articles, were explored. The search design was date escalated from 1980 and included articles in English only. Results and Conclusions: GHRPs bind to two different receptors (GHS-R1a and CD36), which redundantly or independently exert relevant biological effects. GHRPs’ binding to CD36 activates prosurvival pathways such as PI-3K/AKT1, thus reducing cellular death. Furthermore, GHRPs decrease reactive oxygen species (ROS) spillover, enhance the antioxidant defenses, and reduce inflammation. These cytoprotective abilities have been revealed in cardiac, neuronal, gastrointestinal, and hepatic cells, representing a comprehensive spectrum of protection of parenchymal organs. Antifibrotic effects have been attributed to some of the GHRPs by counteracting fibrogenic cytokines. In addition, GHRP family members have shown a potent myotropic effect by promoting anabolia and inhibiting catabolia. Finally, GHRPs exhibit a broad safety profile in preclinical and clinical settings. Despite these fragmented lines incite to envision multiple pharmacological uses for GHRPs, especially as a myocardial reperfusion damage-attenuating candidate, this family of “drugable” peptides awaits for a definitive clinical niche. PMID:28469491

  11. Growth Hormone-Releasing Peptide 6 Enhances the Healing Process and Improves the Esthetic Outcome of the Wounds.

    PubMed

    Mendoza Marí, Yssel; Fernández Mayola, Maday; Aguilera Barreto, Ana; García Ojalvo, Ariana; Bermúdez Alvarez, Yilian; Mir Benítez, Ana Janet; Berlanga Acosta, Jorge

    2016-01-01

    In addition to its cytoprotective effects, growth hormone-releasing peptide 6 (GHRP-6) proved to reduce liver fibrotic induration. CD36 as one of the GHRP-6 receptors appears abundantly represented in cutaneous wounds granulation tissue. The healing response in a scenario of CD36 agonistic stimulation had not been previously investigated. Excisional full-thickness wounds (6 mmØ) were created in the dorsum of Wistar rats and topically treated twice a day for 5 days. The universal model of rabbit's ears hypertrophic scars was implemented and the animals were treated daily for 30 days. Treatments for both species were based on a CMC jelly composition containing GHRP-6 400 μg/mL. Wounds response characterization included closure dynamic, RT-PCR transcriptional profile, histology, and histomorphometric procedures. The rats experiment indicated that GHRP-6 pharmacodynamics involves attenuation of immunoinflammatory mediators, their effector cells, and the reduction of the expression of fibrotic cytokines. Importantly, in the hypertrophic scars rabbit's model, GHRP-6 intervention dramatically reduced the onset of exuberant scars by activating PPARγ and reducing the expression of fibrogenic cytokines. GHRP-6 showed no effect on the reversion of consolidated lesions. This evidence supports the notion that CD36 is an active and pharmacologically approachable receptor to attenuate wound inflammation and accelerate its closure so as to improve wound esthetic.

  12. Growth Hormone-Releasing Peptide 6 Enhances the Healing Process and Improves the Esthetic Outcome of the Wounds

    PubMed Central

    Mendoza Marí, Yssel; Fernández Mayola, Maday; Aguilera Barreto, Ana; García Ojalvo, Ariana; Bermúdez Alvarez, Yilian; Mir Benítez, Ana Janet; Berlanga Acosta, Jorge

    2016-01-01

    In addition to its cytoprotective effects, growth hormone-releasing peptide 6 (GHRP-6) proved to reduce liver fibrotic induration. CD36 as one of the GHRP-6 receptors appears abundantly represented in cutaneous wounds granulation tissue. The healing response in a scenario of CD36 agonistic stimulation had not been previously investigated. Excisional full-thickness wounds (6 mmØ) were created in the dorsum of Wistar rats and topically treated twice a day for 5 days. The universal model of rabbit's ears hypertrophic scars was implemented and the animals were treated daily for 30 days. Treatments for both species were based on a CMC jelly composition containing GHRP-6 400 μg/mL. Wounds response characterization included closure dynamic, RT-PCR transcriptional profile, histology, and histomorphometric procedures. The rats experiment indicated that GHRP-6 pharmacodynamics involves attenuation of immunoinflammatory mediators, their effector cells, and the reduction of the expression of fibrotic cytokines. Importantly, in the hypertrophic scars rabbit's model, GHRP-6 intervention dramatically reduced the onset of exuberant scars by activating PPARγ and reducing the expression of fibrogenic cytokines. GHRP-6 showed no effect on the reversion of consolidated lesions. This evidence supports the notion that CD36 is an active and pharmacologically approachable receptor to attenuate wound inflammation and accelerate its closure so as to improve wound esthetic. PMID:27200188

  13. Use of growth-hormone-releasing peptide-6 (GHRP-6) for the prevention of multiple organ failure.

    PubMed

    Cibrián, Danay; Ajamieh, Hussam; Berlanga, Jorge; León, Olga S; Alba, Jose S; Kim, Micheal J-T; Marchbank, Tania; Boyle, Joseph J; Freyre, Freya; Garcia Del Barco, Diana; Lopez-Saura, Pedro; Guillen, Gerardo; Ghosh, Subrata; Goodlad, Robert A; Playford, Raymond J

    2006-05-01

    Novel therapies for the treatment of MOF (multiple organ failure) are required. In the present study, we examined the effect of synthetic GHRP-6 (growth hormone-releasing peptide-6) on cell migration and proliferation using rat intestinal epithelial (IEC-6) and human colonic cancer (HT29) cells as in vitro models of injury. In addition, we examined its efficacy when given alone and in combination with the potent protective factor EGF (epidermal growth factor) in an in vivo model of MOF (using two hepatic vessel ischaemia/reperfusion protocols; 45 min of ischaemia and 45 min of reperfusion or 90 min of ischaemia and 120 min of reperfusion). In vitro studies showed that GHRP-6 directly influenced gut epithelial function as its addition caused a 3-fold increase in the rate of cell migration of IEC-6 and HT29 cells (P<0.01), but did not increase proliferation ([3H]thymidine incorporation). In vivo studies showed that, compared with baseline values, ischaemia/reperfusion caused marked hepatic and intestinal damage (histological scoring), neutrophilic infiltration (myeloperoxidase assay; 5-fold increase) and lipid peroxidation (malondialdehyde assay; 4-fold increase). Pre-treatment with GHRP-6 (120 microg/kg of body weight, intraperitoneally) alone truncated these effects by 50-85% (all P<0.05) and an additional benefit was seen when GHRP-6 was used in combination with EGF (1 mg/kg of body weight, intraperitoneally). Lung and renal injuries were also reduced by these pre-treatments. In conclusion, administration of GHRP-6, given alone or in combination with EGF to enhance its effects, may provide a novel simple approach for the prevention and treatment of MOF and other injuries of the gastrointestinal tract. In view of these findings, further studies appear justified.

  14. Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers.

    PubMed

    Cabrales, Ania; Gil, Jeovanis; Fernández, Eduardo; Valenzuela, Carmen; Hernández, Francisco; García, Idrián; Hernández, Ariadna; Besada, Vladimir; Reyes, Osvaldo; Padrón, Gabriel; Berlanga, Jorge; Guillén, Gerardo; González, Luis Javier

    2013-01-23

    GHRP-6 is a growth hormone secretagogue that also enhances tissue viability in different organs. In the present work, we studied the pharmacokinetics of this short therapeutic hexapeptide (His-(D-Trp)-Ala-Trp-(D-Phe)-Lys-NH(2,) MW=872.44 Da) in nine male healthy volunteers after a single intravenous bolus administration of 100, 200 and 400 μg/kg of body weight. GHRP-6 was quantified in human plasma by a specific LC-MS method, previously developed and validated following FDA guidelines, using (13)C(3)Ala-GHRP-6 as internal standard (Gil et al., 2012, J. Pharm. Biomed. Anal. 60, 19-25). The Lower Limit of Quantification (5 ng/mL) was reached in all subjects at 12h post-administration, which was sufficient for modeling a pharmacokinetic profile including over 85% of the Area under the Curve (AUC). Disposition of GHRP-6 best fitted a bi-exponential function with R(2) higher than 0.99, according to a mathematic modeling and confirmed by an Akaike index (AIC) lower than that of the corresponding one-compartment model for all subjects. Averaging all three dose levels, the distribution and elimination half-life of GHRP-6 were 7.6 ± 1.9 min and 2.5 ± 1.1h, respectively. These values are coherent with existing data for other drugs whose disposition also fits this model. Dose dependence analysis revealed a noticeable trend for AUC to increase proportionally with administered dose. Atypical GHRP-6 concentration spikes were observed during the elimination phase in four out of the nine subjects studied.

  15. Effect of growth hormone releasing hormone (GHRH) and vasoactive intestinal peptide (VIP) on in vitro bovine oocyte maturation.

    PubMed

    Beker, A R; Izadyar, F; Colenbrander, B; Bevers, M M

    2000-06-01

    The aim of this study was to investigate the effects of growth hormone releasing hormone (GHRH) and the structural-related peptide vasoactive intestinal peptide (VIP) on nuclear maturation, cortical granule distribution and cumulus expansion of bovine oocytes. Bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of either 100 ng/mL bovine GHRH or 100 ng/mL porcine VIP. The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air, and the nuclear stage was assessed after 16 or 24 h of incubation using DAPI staining. Cortical granule distribution was assessed after 24 h of incubation using FITC-PNA staining. To assess the effects of GHRH and VIP on cumulus expansion, COCs were incubated for 24 h under the conditions described above. In addition, 0.05 IU/mL recombinant human FSH was added to GHRH and VIP groups. Cultures without GHRH/VIP/FSH or with only FSH served as negative and positive controls, respectively. At 16 h neither GHRH (42.9%) nor VIP (38.5%) influenced the percentage of MII stage oocytes compared with their respective controls (44.2 and 40.8%). At 24 h there also was no difference in the percentage of MII oocytes between GHRH (77.0%), VIP (75.3%) and their respective controls (76.0 and 72%). There was no significant cumulus expansion in the GHRH or VIP group, while FSH induced significant cumulus expansion compared with the control groups, which were not inhibited by GHRH or VIP. Distribution of cortical granules was negatively affected by GHRH and VIP. The percentage of oocytes showing more or less evenly dispersed cortical granules in the cortical cytoplasm aligning the oolemma (Type 3) was lower in the GHRH (2.7%) and VIP (7.8%) groups than in the control group (15.9%). In conclusion, GHRH and VIP have no effect on nuclear maturation or cumulus expansion of bovine COCs but retard cytoplasmic maturation, as reflected by delayed cortical granule migration.

  16. Ghrelin and obestatin modulate growth hormone-releasing hormone release and synaptic inputs onto growth hormone-releasing hormone neurons.

    PubMed

    Feng, Dan D; Yang, Seung-Kwon; Loudes, Catherine; Simon, Axelle; Al-Sarraf, Tamara; Culler, Michael; Alvear-Perez, Rodrigo; Llorens-Cortes, Catherine; Chen, Chen; Epelbaum, Jacques; Gardette, Robert

    2011-09-01

    Ghrelin, a natural ligand of the growth hormone secretagogue receptor (GHS-R), is synthesized in the stomach but may also be expressed in lesser quantity in the hypothalamus where the GHS-R is located on growth hormone-releasing hormone (GHRH) neurons. Obestatin, a peptide derived from the same precursor as ghrelin, is able to antagonize the ghrelin-induced increase of growth hormone (GH) secretion in vivo but not from pituitary explants in vitro. Thus, the blockade of ghrelin-induced GH release by obestatin could be mediated at the hypothalamic level by the neuronal network that controls pituitary GH secretion. Ghrelin increased GHRH and decreased somatostatin (somatotropin-releasing inhibitory factor) release from hypothalamic explants, whereas obestatin only reduced the ghrelin-induced increase of GHRH release, thus indicating that the effect of ghrelin and obestatin is targeted to GHRH neurons. Patch-clamp recordings on mouse GHRH-enhanced green fluorescent protein neurons indicated that ghrelin and obestatin had no significant effects on glutamatergic synaptic transmission. Ghrelin decreased GABAergic synaptic transmission in 44% of the recorded neurons, an effect blocked in the presence of the GHS-R antagonist BIM28163, and stimulated the firing rate of 78% of GHRH neurons. Obestatin blocked the effects of ghrelin by acting on a receptor different from the GHS-R. These data suggest that: (i) ghrelin increases GHRH neuron excitability by increasing their action potential firing rate and decreasing the strength of GABA inhibitory inputs, thereby leading to an enhanced GHRH release; and (ii) obestatin counteracts ghrelin actions. Such interactions on GHRH neurons probably participate in the control of GH secretion.

  17. Azapeptide analogues of the growth hormone releasing peptide 6 as cluster of differentiation 36 receptor ligands with reduced affinity for the growth hormone secretagogue receptor 1a.

    PubMed

    Proulx, Caroline; Picard, Émilie; Boeglin, Damien; Pohankova, Petra; Chemtob, Sylvain; Ong, Huy; Lubell, William D

    2012-07-26

    The synthetic hexapeptide growth hormone releasing peptide-6 (GHRP-6) exhibits dual affinity for the growth hormone secretagogue receptor 1a (GHS-R1a) and the cluster of differentiation 36 (CD36) receptor. Azapeptide GHRP-6 analogues have been synthesized, exhibiting micromolar affinity to the CD36 receptor with reduced affinity toward the GHS-R1a. A combinatorial split-and-mix approach furnished aza-GHRP-6 leads, which were further examined by alanine scanning. Incorporation of an aza-amino acid residue respectively at the D-Trp(2), Ala(3), or Trp(4) position gave aza-GHRP-6 analogues with reduced affinity toward the GHS-R1a by at least a factor of 100 and in certain cases retained affinity for the CD36 receptor. In the latter cases, the D-Trp(2) residue proved important for CD36 receptor affinity; however, His(1) could be replaced by Ala(1) without considerable loss of binding. In a microvascular sprouting assay using a choroid explant, [azaTyr(4)]-GHRP-6 (15), [Ala(1), azaPhe(2)]-GHRP-6 (16), and [azaLeu(3), Ala(6)]-GHRP-6 (33) all exhibited antiangiogenic activity.

  18. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

    PubMed

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-09-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.

  19. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I

    PubMed Central

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-01-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506] PMID:25644636

  20. Growth hormone releasing peptide-6 enhanced antibody titers against subunit antigens in mice (BALB/c), tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus).

    PubMed

    Martínez, Rebeca; Hernández, Liz; Gil, Lázaro; Carpio, Yamila; Morales, Antonio; Herrera, Fidel; Rodríguez-Mallón, Alina; Leal, Yeny; Blanco, Aracelys; Estrada, Mario Pablo

    2017-10-09

    Modern subunit vaccines have excellent safety profiles and improved tolerability, but do not elicit strong immune responses without the addition of adjuvants. Developing a safe and affective adjuvant remains a challenge for peptide-based vaccine design. Growth Hormone Releasing Peptide-6 (GHRP-6) is one of the earliest-developed, synthetic, peptidyl growth hormone secretagogue receptor agonists. These compounds mimic the effect of the endogenous ligand, ghrelin. In the present study, we evaluated the ability of GHRP-6 to enhance the humoral immune response against co-injected antigens in mice, tilapia and African catfish. This peptide was able to increase the antigen-specific antibody response using heterologous proteins and peptides as antigens, which were also formulated in "water in oil" emulsions (Freund and Montanide). As long as we know there is no previous report describing any ghrelin analogous as molecular immunomodulator stimulating a humoral immune response. Further studies will be conducted to evaluate the functionality of this humoral immune response in challenge trials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Growth Hormone-Releasing Hormone in Diabetes

    PubMed Central

    Fridlyand, Leonid E.; Tamarina, Natalia A.; Schally, Andrew V.; Philipson, Louis H.

    2016-01-01

    Growth hormone-releasing hormone (GHRH) is produced by the hypothalamus and stimulates growth hormone synthesis and release in the anterior pituitary gland. In addition, GHRH is an important regulator of cellular functions in many cells and organs. Expression of GHRH G-Protein Coupled Receptor (GHRHR) has been demonstrated in different peripheral tissues and cell types, including pancreatic islets. Among the peripheral activities, recent studies demonstrate a novel ability of GHRH analogs to increase and preserve insulin secretion by beta-cells in isolated pancreatic islets, which makes them potentially useful for diabetes treatment. This review considers the role of GHRHR in the beta-cell and addresses the unique engineered GHRH agonists and antagonists for treatment of type 2 diabetes mellitus. We discuss the similarity of signaling pathways activated by GHRHR in pituitary somatotrophs and in pancreatic beta-cells and possible ways as to how the GHRHR pathway can interact with glucose and other secretagogues to stimulate insulin secretion. We also consider the hypothesis that novel GHRHR agonists can improve glucose metabolism in Type 2 diabetes by preserving the function and survival of pancreatic beta-cells. Wound healing and cardioprotective action with new GHRH agonists suggest that they may prove useful in ameliorating certain diabetic complications. These findings highlight the future potential therapeutic effectiveness of modulators of GHRHR activity for the development of new therapeutic approaches in diabetes and its complications. PMID:27777568

  2. Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin.

    PubMed

    Semenistaya, Ekaterina; Zvereva, Irina; Thomas, Andreas; Thevis, Mario; Krotov, Grigory; Rodchenkov, Grigory

    2015-10-01

    Growth hormone releasing peptides (GHRPs) stimulate secretion of endogenous growth hormone and are listed on the World Anti-Doping Agency (WADA) Prohibited List. To develop an effective method for GHRPs anti-doping control we have investigated metabolites of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin in urine after nasal administration. Each compound was administrated to one volunteer. Samples were collected for 2 days after administration, processed by solid-phase extraction on weak cation exchange cartridges and analyzed by means of nano-liquid chromatography - high resolution mass spectrometry. Six metabolites of GHRP-1 were identified. GHRP-1 in the parent form was not detected. GHRP-1 (2-4) free acid was detected in urine up to 27 h. GHRP-2, GHRP-2 free acid and GHRP-2 (1-3) free acid were detected in urine up to 47 h after administration. GHRP-6 was mostly excreted unchanged and detected in urine 23 h after administration, its metabolites were detectable for 12 h only. Hexarelin and Ipamorelin metabolized intensively and were excreted as a set of parent compounds with metabolites. Hexarelin (1-3) free acid and Ipamorelin (1-4) free acid were detected in urine samples after complete withdrawal of parent substances. GHRPs and their most prominent metabolites were included into routine ultra-pressure liquid chromatography-tandem mass spectrometry procedure. The method was fully validated, calibration curves of targeted analytes were obtained and excretion curves of GHRPs and their metabolites were plotted. Our results confirm that the detection window after GHRPs administration depends on individual metabolism, drug preparation form and the way of administration.

  3. Central effects of growth hormone-releasing hexapeptide (GHRP-6) on growth hormone release are inhibited by central somatostatin action.

    PubMed

    Fairhall, K M; Mynett, A; Robinson, I C

    1995-03-01

    Growth hormone (GH) release is stimulated by a variety of synthetic secretagogues, of which growth hormone-releasing hexapeptide (GHRP-6) has been most thoroughly studied; it is thought to have actions at both pituitary and hypothalamic sites. To evaluate the central actions of this peptide, we have studied GH release in response to direct i.c.v. injections in anaesthetized guinea pigs. GHRP-6 (0.04-1 microgram) stimulated GH release > 10-fold 30-40 min after i.c.v. injection. The same GH response required > 20-fold more GHRP-6 when given by i.v. injection. GH release could also be elicited by a non-peptide GHRP analogue (L-692,585, 1 microgram i.c.v.), whereas a growth hormone-releasing factor (GRF) analogue (human GRF27Nle(1-29)NH2, 2 micrograms, i.c.v.) was ineffective. A long acting somatostatin analogue (Sandostatin, SMS 201-995, 10 micrograms i.c.v.) (SMS) given 20 min before 200 ng GHRP-6 blocked GH release. This was unlikely to be due to a direct effect of SMS leaking out to the pituitary, since central SMS injections did not affect basal GH release, nor did they block GH release in response to i.v. GRF injections. We conclude that the hypothalamus is a major target for GHRP-6 in vivo. Since the GH release induced by central GHRP-6 injections can be inhibited by a central action of somatostatin, and other data indicate that GHRP-6 activates GRF neurones, we suggest that somatostatin may block this activation via receptors known to be located on or near the GRF cells themselves. Somatostatin may therefore be a functional antagonist of GHRP-6 acting centrally, as well as at the pituitary gland.

  4. Nutrient Sensing Overrides Somatostatin and Growth Hormone-Releasing Hormone to Control Pulsatile Growth Hormone Release.

    PubMed

    Steyn, F J

    2015-07-01

    Pharmacological studies reveal that interactions between hypothalamic inhibitory somatostatin and stimulatory growth hormone-releasing hormone (GHRH) govern pulsatile GH release. However, in vivo analysis of somatostatin and GHRH release into the pituitary portal vasculature and peripheral GH output demonstrates that the withdrawal of somatostatin or the appearance of GHRH into pituitary portal blood does not reliably dictate GH release. Consequently, additional intermediates acting at the level of the hypothalamus and within the anterior pituitary gland are likely to contribute to the release of GH, entraining GH secretory patterns to meet physiological demand. The identification and validation of the actions of such intermediates is particularly important, given that the pattern of GH release defines several of the physiological actions of GH. This review highlights the actions of neuropeptide Y in regulating GH release. It is acknowledged that pulsatile GH release may not occur selectively in response to hypothalamic control of pituitary function. As such, interactions between somatotroph networks, the median eminence and pituitary microvasculature and blood flow, and the emerging role of tanycytes and pericytes as critical regulators of pulsatility are considered. It is argued that collective interactions between the hypothalamus, the median eminence and pituitary vasculature, and structural components within the pituitary gland dictate somatotroph function and thereby pulsatile GH release. These interactions may override hypothalamic somatostatin and GHRH-mediated GH release, and modify pulsatile GH release relative to the peripheral glucose supply, and thereby physiological demand.

  5. Effect of growth hormone-releasing factor on growth hormone release in children with radiation-induced growth hormone deficiency

    SciTech Connect

    Lustig, R.H.; Schriock, E.A.; Kaplan, S.L.; Grumbach, M.M.

    1985-08-01

    Five male children who received cranial irradiation for extrahypothalamic intracranial neoplasms or leukemia and subsequently developed severe growth hormone (GH) deficiency were challenged with synthetic growth hormone-releasing factor (GRF-44), in an attempt to distinguish hypothalamic from pituitary dysfunction as a cause of their GH deficiency, and to assess the readily releasable GH reserve in the pituitary. In response to a pulse of GRF-44 (5 micrograms/kg intravenously), mean peak GH levels rose to values higher than those evoked by the pharmacologic agents L-dopa or arginine (6.4 +/- 1.3 ng/mL v 1.5 +/- 0.4 ng/mL, P less than .05). The peak GH value occurred at a mean of 26.0 minutes after administration of GRF-44. These responses were similar to those obtained in children with severe GH deficiency due to other etiologies (peak GH 6.3 +/- 1.7 ng/mL, mean 28.0 minutes). In addition, there was a trend toward an inverse relationship between peak GH response to GRF-44 and the postirradiation interval. Prolactin and somatomedin-C levels did not change significantly after the administration of a single dose of GRF-44. The results of this study support the hypothesis that cranial irradiation in children can lead to hypothalamic GRF deficiency secondary to radiation injury of hypothalamic GRF-secreting neurons. This study also lends support to the potential therapeutic usefulness of GRF-44 or an analog for GH deficiency secondary to cranial irradiation.

  6. Algorithmic complexity of growth hormone release in humans

    SciTech Connect

    Prank, K.; Wagner, M.; Brabant, G.

    1996-12-31

    Most hormones are secreted in an pulsatile rather than in a constant manner. This temporal pattern of pulsatile hormone release plays an important role in the regulation of cellular function and structure. In healthy humans growth hormone (GH) secretion is characterized by distinct pulses whereas patients bearing a GH producing tumor accompanied with excessive secretion (acromegaly) exhibit a highly irregular pattern of GH release. It has been hypothesized that this highly disorderly pattern of GH release in acromegaly arises from random events in the GH-producing tumor under decreased normal control of GH secretion. Using a context-free grammar complexity measure (algorithmic complexity) in conjunction with random surrogate data sets we demonstrate that the temporal pattern of GH release in acromegaly is not significantly different from a variety of stochastic processes. In contrast, normal subjects clearly exhibit deterministic structure in their temporal patterns of GH secretion. Our results support the hypothesis that GH release in acromegaly is due to random events in the GH-producing tumorous cells which might become independent from hypothalamic regulation. 17 refs., 1 fig., 2 tabs.

  7. The positive effects of growth hormone-releasing peptide-6 on weight gain and fat mass accrual depend on the insulin/glucose status.

    PubMed

    Granado, Miriam; García-Cáceres, Cristina; Frago, Laura M; Argente, Jesús; Chowen, Julie A

    2010-05-01

    Ghrelin and GH secretagogues, including GH-releasing peptide (GHRP)-6, stimulate food intake and adiposity. Because insulin modulates the hypothalamic response to GH secretagogues and acts synergistically with ghrelin on lipogenesis in vitro, we analyzed whether insulin plays a role in the metabolic effects of GHRP-6 in vivo. Streptozotocin-induced diabetic rats received saline, GHRP-6, insulin, or insulin plus GHRP-6 once daily for 8 wk. Rats receiving saline suffered hyperglycemia, hyperphagia, polydipsia, and weight loss. Insulin, but not GHRP-6, improved these parameters (P < 0.001 for all), as well as the diabetes-induced increase in hypothalamic mRNA levels of neuropeptide Y and agouti-related peptide and decrease in proopiomelanocortin. Cocaine amphetamine-related transcript mRNA levels were also reduced in diabetic rats, with GHRP-6 inducing a further decrease (P < 0.03) and insulin an increase. Diabetic rats receiving insulin plus GHRP-6 gained more weight and had increased epididymal fat mass and serum leptin levels compared with all other groups (P < 0.001). In epididymal adipose tissue, diabetic rats injected with saline had smaller adipocytes (P < 0.001), decreased fatty acid synthase (FAS; P < 0.001), and glucose transporter-4 (P < 0.001) and increased hormone sensitive lipase (P < 0.001) and proliferator-activated receptor-gamma mRNA levels (P < 0.01). Insulin normalized these parameters to control values. GHRP-6 treatment increased FAS and glucose transporter-4 gene expression and potentiated insulin's effect on epididymal fat mass, adipocyte size (P < 0.001), FAS (P < 0.001), and glucose transporter-4 (P < 0.05). In conclusion, GHRP-6 and insulin exert an additive effect on weight gain and visceral fat mass accrual in diabetic rats, indicating that some of GHRP-6's metabolic effects depend on the insulin/glucose status.

  8. Induction of growth hormone release by Pueraria thunbergiana BENTH.

    PubMed

    Jung, D Y; Ha, H; Kim, C

    2004-02-01

    Puerariae Radix (PR), Puerariae Flos (PF), and Puerariae Surculus (PS) as well as their constituents were tested for induction of rat growth hormone (rGH) release by both rat pituitary cell culture and in vivo experimentation in order to develop them to novel drugs. Through a calibration curve of the rGH released by addition of rat growth hormone-releasing hormone (rGHRH) to rat pituitary cells, the 70 % ethanol extracts of PR and PS increased rGH release by about 1.6 and 1.7 times as high, respectively, as the control group (264.6 +/- 13.6 pM). However, each puerarin type as a representative constituent of PR in Korea Pharmacopeia (KP) and tectorigenin and an important ingredient of PF were twice as effective as in the control group. The acid hydrolysate of Puerariae Surculus (HPS) increased rGH release concentration-dependently, and its EC (50) was approximately 10.4 microg/ml. The T (max) value for rGH after injection of 20 microg/kg of rGHRH was 10 - 30 min, while the C (max) value was increased by approximately 12-fold compared to the control group (198.2 +/- 25.0 pM) and the AUC (0 - 45) was increased to 10 times the level of the control group (10,840.9 +/- 845.5 min. pM). On the other hand, T (max) for the HPS was 60 min, while C (max) was increased approximately to 5.8 fold compared to control (244.1 +/- 36.4 pM). C (max) for puerarin was 1,028.6 +/- 502.7 pM, that is, approximately 5.2 times as high as the control level. However, tectorigenin (20 microg/kg) was of no statistical significance. Therefore, we suggest that the HPS and puerarin act either on GH secretagogue receptors or on GHRH receptor of somatotrophin as possible agonists or an inhibitor on somatostatin receptor to release rGH, respectively.

  9. Structural study of human growth hormone-releasing factor fragment (1?29) by vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Carmona, P.; Molina, M.; Lasagabaster, A.

    1995-05-01

    The conformational structure of fragment 1-29 of human growth hormone releasing factor, hGHRF (1-29), in aqueous solution and in the solid state is investigated by infrared and Raman spectroscopy. The polypeptide backbone is found to be unordered in the solid state. However, the spectra of the peptide prepared as 5% (w/w) aqueous solutions show that approximately 28% of the peptide is involved in intermolecular β-sheet aggregation. The remainder of the peptide exists largely as disordered and β-sheet conformations with a small portion of α-helices. Tyrosine residues are found to be exposed to the solvent. The secondary structures are quantitatively examined through infrared spectroscopy, the conformational percentages being near those obtained by HONDAet al. [ Biopolymers31, 869 (1991)] using circular dichroism. The fast hydrogen/deuterium exchange in peptide groups and the absence of any NMR sign indicative of ordered structure [ G. M. CLOREet al., J. Molec. Biol.191, 553 (1986)] support that the solution conformations of the non-aggregated peptide interconvert in dynamic equilibrium. Some physiological advantages that may derive from this conformational flexibility are also discussed

  10. How does growth hormone releasing hexapeptide self-assemble in nanotubes?

    PubMed

    Santana, Héctor; Avila, Cesar L; Cabrera, Ingrid; Páez, Rolando; Falcón, Viviana; Pessoa, Adalberto; Ventosa, Nora; Veciana, Jaume; Itri, Rosangela; Barbosa, Leandro Ramos Souza

    2014-12-14

    Growth hormone releasing peptide, GHRP-6, a hexapeptide (His-(D-Trp)-Ala-Trp-(D-Phe)-Lys-NH2, MW = 872.44 Da) that belongs to a class of synthetic growth hormone secretagogues, can stimulate growth hormone secretion from somatotrophs in several species including humans. In the present study, we demonstrate that GHRP-6 dispersed in aqueous solution, at pH 7.0, room temperature of 22 °C, is able to form long nanotubes, which is evidenced by combining small angle X-ray scattering (SAXS), transmission electron microscopy and molecular dynamics simulation results. Such nanotubes possess inner and outer cross-sections equal to 6.7(2) nm and 13.4(5) nm, respectively. The mechanism of peptide self-assembly was determined by molecular dynamics simulations revealing that the peptides self-assemble like amphiphilic molecules in aqueous solution in a partially interdigitated structure. In this case, the position of the positively charged amino terminus is located at the peptide-water interface, whereas the neutral NH2-capped carboxy terminus remains buried at the hydrophobic core. In contrast, the long side chain of Lys-6 stretches out of the hydrophobic core positioning its positive charge near the cylinder surface. The peptide configuration in the nanotube wall comes from the interplay between the hydrophobic interactions of the aromatic side chains of GHRP-6 and the electrostatic repulsion of its cationic charges. On increasing the peptide concentration, the long nanotubes self-arrange in solution displaying a bi-dimensional hexagonal-like packing in the SAXS curves, with a center-to-center distance of ∼15 nm. Further, we also show that the nanostructure formed in solution is quite stable and is preserved following transfer to a solid support.

  11. Peripheral activities of growth hormone-releasing hormone.

    PubMed

    Granata, R

    2016-07-01

    Growth hormone (GH)-releasing hormone (GHRH) is produced by the hypothalamus and stimulates GH synthesis and release in the anterior pituitary gland. In addition to its endocrine role, GHRH exerts a wide range of extrapituitary effects which include stimulation of cell proliferation, survival and differentiation, and inhibition of apoptosis. Accordingly, expression of GHRH, as well as the receptor GHRH-R and its splice variants, has been demonstrated in different peripheral tissues and cell types. Among the direct peripheral activities, GHRH regulates pancreatic islet and β-cell survival and function and endometrial cell proliferation, promotes cardioprotection and wound healing, influences the immune and reproductive systems, reduces inflammation, indirectly increases lifespan and adiposity and acts on skeletal muscle cells to inhibit cell death and atrophy. Therefore, it is becoming increasingly clear that GHRH exerts important extrapituitary functions, suggesting potential therapeutic use of the peptide and its analogs in a wide range of medical settings.

  12. Purification of a high-molecular-weight somatoliberin (growth-hormone-releasing factor) from pig hypothalami.

    PubMed Central

    Sykes, J E; Lowry, P J

    1983-01-01

    Preliminary observations [Sykes & Lowry (1980) J. Endocrinol. 85, 42P-43P] had suggested that the major hypothalamic somatoliberin (growth-hormone-releasing factor) was a larger peptide than the other characterized hypothalamic factors, with an elution position on Sephadex G-50 between those of neurophysin and corticotropin. The present paper reports the isolation and preliminary characterization of pig hypothalamic somatoliberin. Acid extracts of pig stalk median eminence were purified by gel filtration and preparative and analytical high-pressure liquid chromatography to yield a preparation that was specific in the release of somatotropin (growth hormone) in vitro, giving a steep dose--response curve at doses in the range 0.20-3.0 ng. Amino acid analysis revealed a non-cysteine-containing peptide with a high number of glutamate (or glutamine) and aspartate (or asparagine) residues. The peptide had about 56-57 amino acid residues and an apparent molecular weight of 6400, in keeping with its elution position on a column of Sephadex G-50. PMID:6409074

  13. Spectroscopic studies on the conformational transitions of a bovine growth hormone releasing factor analog

    NASA Astrophysics Data System (ADS)

    Sarver, Ronald W.; Friedman, Alan R.; Thamann, Thomas J.

    1997-10-01

    The secondary structure of the bovine growth hormone releasing factor analog, [Ile 2, Ser 8,28, Ala 15, Leu 27, Hse 30] bGRF(1-30)-NH-Ethyl, acetate salt (U-90699F) was studied in solution by Fourier transform infrared and Raman spectroscopies. Spectroscopic studies revealed that concentrated aqueous solutions of U-90699F (100 mg ml -1) undergo a secondary structure transition from disordered coil/α-helix to intermolecular β-sheet. Disordered coil and α-helical structure were grouped together in the infrared and Raman studies since the amide I vibrations are close in frequency and overlap in assignments was possible. Before the conformational transition, the facile exchange of the peptide's amide hydrogens for deuterium indicated that the majority of amide hydrogens were readily accessible to solvent. The kinetics of the conformational transition coincided with an increase in solution viscosity and turbidity. An initiation phase preceded the conformational transition during which only minor spectral changes were observed by infrared spectroscopy. The initiation phase and reaction kinetics were consistent with a highly cooperative nucleation ultimately leading to a network of intermolecular β-sheet structure and gel formation. Increased temperature accelerated the conformational transition. The conformational transition was thermally irreversible but the β-sheet structure of aggregated or gelled peptide could be disrupted by dilution and agitation.

  14. The Physiology of Growth Hormone-Releasing Hormone (GHRH) in Breast Cancer

    DTIC Science & Technology

    2003-06-01

    production of growth hormone-releasing factor by carcinoid and pancreatic islet tumors associated with acromegaly . Prog Clin Biol Res 1981; 74:259-271. (16...promotion of apop- cause of acromegaly . More recently, expression has been tosis. These results indicate that disruption of enaog- demonstrated in tumors

  15. Conformational origin of a difficult coupling in a human growth hormone releasing factor analog.

    PubMed

    Deber, C M; Lutek, M K; Heimer, E P; Felix, A M

    1989-01-01

    During the solid-phase synthesis of the human growth hormone releasing factor (GRF) analog [Ala15, Leu27, Asn28] -GRF(1-32)-OH, incorporation of Boc-Gln16 was determined to be incomplete. While aggregation of growing resin-bound peptide chains with concomitant beta-sheet formation and "precipitation" has been proposed to account in general for such "difficult coupling," no feature of sequence in the Gln16 region of this GRF analog provided an immediate rationale for this result. We now report 500 MHz 1H NMR spectra of a series of resin-bound GRF segments surrounding the Gln16 position (19-32 through 14-32), swelled in dimethylsulfoxide-d6 solutions [GRF(14-32) = Leu14-Ala-Gln-Leu-Ser(Bzl)-Ala-Arg(Tos)-Lys(CIZ)-Leu- Leu-Gln-Asp(OcHex)-Ile-Leu-Asn-Arg(Tos)-Gln-Gln-Gly32-PAM resin]. While relatively sharp spectra are observed for GRF(19-32), components with resonances broadened by an order-of-magnitude appear in spectra of the 18-32 and 17-32 peptide-resin, and the entire spectrum of 16-32 is ill-resolved and highly broadened. Subsequent spectra sharpen again (15-32, 14-32). These combined synthesis/spectroscopic experimental results, in conjunction with predictive analyses using standard Chou-Fasman 2 degrees structure parameters, suggest that the completeness of the Gln16 coupling is hindered by formation of a specific, folded beta-sheet/beta-turn structure in GRF(16-32) (with the turn located at 18-21, "upstream" of the difficult coupling site), and accompanying aggregation of peptide chains. This analysis suggests that awareness of such potential beta-sheet/beta-turn sequences can guide analog choices, and/or facilitate pre-programming of synthesis steps in anticipation of problem couplings.

  16. Search for novel therapies for triple negative breast cancers (TNBC): analogs of luteinizing hormone-releasing hormone (LHRH) and growth hormone-releasing hormone (GHRH).

    PubMed

    Buchholz, Stefan; Seitz, Stephan; Engel, Jörg B; Montero, Alberto; Ortmann, Olaf; Perez, Roberto; Block, Norman L; Schally, Andrew V

    2012-04-01

    Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that is clinically negative for the expression of estrogen and progesterone receptors (ER/PR) and human epidermal growth factor receptor-2 (HER2). Patients with TNBC have a worse clinical outcome, as measured by time to metastasis and median overall survival. Chemotherapy has been the mainstay of treatment of TNBC but responses are disappointing. A substantial proportion of TNBC expresses luteinizing hormone-releasing hormone (LHRH), receptors for LHRH, in addition to receptors for growth hormone-releasing hormone (GHRH). These receptors represent potential therapeutic targets. Potent antagonists of GHRH and LHRH receptors have been developed in recent years and these antagonists inhibit the growth, tumorigenicity and metastatic potential of various human experimental malignancies. These antagonists could be utilized for the treatment of TNBC. The targeted cytotoxic analog of LHRH, AN-152 (AEZS-108) containing doxorubicin, must also be strongly considered for therapy of TNBC. Experimental studies suggest the merit of clinical trials with LHRH antagonists and AEZS-108 in TNBC patients.

  17. [Phe4]somatostatin: a potent, selective inhibitor of growth hormone release.

    PubMed Central

    Meyers, C A; Coy, D H; Murphy, W A; Redding, T W; Arimura, A; Schally, A V

    1980-01-01

    [Phe4]Somatostatin was twice as active as somatostatin (SS) in suppressing rat growth hormone release in vitro but had only weak activity toward inhibition of insulin and glucagon release in vivo. The ability of this analogue to inhibit growth hormone release more actively than SS was confirmed in vivo by two separately designed bioassays. Further structure/activity studies of position 4 were carried out with [Glu4]SS, [Thr4]SS, and des-Lys4-SS, all of which had negligible inhibiting activity in the pituitary and pancreas. In this context the strikingly selective activity of [Phe4]SS suggests a fundamental difference in the SS receptors of pituitary and pancreas and the normal side-chain basicity of position 4 appears to be more important for action in pancreas than in pituitary. [Phe4]SS has properties that may be useful in the development of agents for the treatment of acromegaly or other disorders associated with increased growth hormone levels. PMID:6987657

  18. Identification of the growth hormone-releasing hormone analogue [Pro1, Val14]-hGHRH with an incomplete C-term amidation in a confiscated product.

    PubMed

    Esposito, Simone; Deventer, Koen; Van Eenoo, Peter

    2014-01-01

    In this work, a modified version of the 44 amino acid human growth hormone-releasing hormone (hGHRH(1-44)) containing an N-terminal proline extension, a valine residue in position 14, and a C-terminus amidation (sequence: PYADAIFTNSYRKVVLGQLSARKLLQDIMSRQQGESNQERGARARL-NH2 ) has been identified in a confiscated product by liquid chromatography-high resolution mass spectrometry (LC-HRMS). Investigation of the product suggests also an incomplete C-term amidation. Similarly to other hGHRH analogues, available in black markets, this peptide can potentially be used as performance-enhancing drug due to its growth hormone releasing activity and therefore it should be considered as a prohibited substance in sport. Additionally, the presence of partially amidated molecule reveals the poor pharmaceutical quality of the preparation, an aspect which represents a big concern for public health as well. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Insulin and growth hormone-releasing peptide-6 (GHRP-6) have differential beneficial effects on cell turnover in the pituitary, hypothalamus and cerebellum of streptozotocin (STZ)-induced diabetic rats.

    PubMed

    Granado, Miriam; García-Cáceres, Cristina; Tuda, María; Frago, Laura M; Chowen, Julie A; Argente, Jesús

    2011-04-30

    Poorly controlled type1 diabetes is associated with hormonal imbalances and increased cell death in different tissues, including the pituitary, hypothalamus and cerebellum. In the pituitary, lactotrophs are the cell population with the greatest increase in cell death, whereas in the hypothalamus and cerebellum astrocytes are most highly affected. Insulin treatment can delay, but does not prevent, diabetic complications. As ghrelin and growth hormone (GH) secretagogues are reported to prevent apoptosis in different tissues, and to modulate glucose homeostasis, a combined hormonal treatment may be beneficial. Hence, we analyzed the effect of insulin and GH-releasing peptide 6 (GHRP-6) on diabetes-induced apoptosis in the pituitary, hypothalamus and cerebellum of diabetic rats. Adult male Wistar rats were made diabetic by streptozotocin injection (65 mg/kg ip) and divided into four groups from diabetes onset: those receiving a daily sc injection of saline (1 ml/kg/day), GHRP-6 (150 μg/kg/day), insulin (1-8U/day) or insulin plus GHRP-6 for 8 weeks. Control non-diabetic rats received saline (1 ml/kg/day). Diabetes increased cell death in the pituitary, hypothalamus and cerebellum (P<0.05). In the pituitary, insulin treatment prevented diabetes-induced apoptosis (P<0.01), as well as the decline in prolactin and GH mRNA levels (P<0.05). In the hypothalamus, neither insulin nor GHRP-6 decreased diabetes-induced cell death. However, the combined treatment of insulin+GHRP-6 prevented the diabetes induced-decrease in glial fibrillary acidic protein (GFAP) levels (P<0.05). In the cerebellum, although insulin treatment increased GFAP levels (P<0.01), only the combined treatment of insulin+ GHRP-6 decreased diabetes-induced apoptosis (P<0.05). In conclusion, insulin and GHRP-6 exert tissue specific effects in STZ-diabetic rats and act synergistically on some processes. Indeed, insulin treatment does not seem to be effective on preventing some of the diabetes-induced alterations

  20. Combined nuclear magnetic resonance spectroscopy and molecular dynamics study of growth hormone releasing hexapeptide GHRP-6 and a cyclic analogue.

    PubMed

    Fernández-Oliva, Miguel; Santana, Héctor; Suardíaz, Reynier; Gavín, José A; Pérez, Carlos S

    2012-05-01

    The Growth Hormone Releasing Hexapeptide, GHRP-6 was the first of a family of synthetic peptides that enhance the release of the Growth Hormone by the pituitary gland in a dose-dependent manner. Since its discovery, it has been used as a benchmark and starting point in numerous researches aiming to obtain new drugs. Complete resonance assignment of GHRP-6 NMR spectra in both open and cyclic forms are reported, showing some differences to random coil chemical shifts. Connectivities observed in the ROESY spectra indicate spatial proximity between the aromatic residues side-chains in both molecules, as well as between residues DPhe5 and Lys6 sidechains. An ensemble of 10 structures was generated for each one of the molecules, showing RMSD values indicative of nonrandom structures. Molecular Dynamics simulations, both with and without explicit solvent, were carried out for GHRP-6 and its cyclic analogue. Conformational analysis performed on the trajectories showed a nonrandom structure with a well preserved backbone. The presence of geometrical patterns resembling those typical of π-π interactions in both peptides, suggest that this kind of interactions may be relevant for the biological activity of GHRP-6. Same conclusion can be drawn from the spatial proximity of residues DPhe5 and Lys6 sidechains.

  1. Long-term effects of human growth hormone-releasing hormone and photoperiod on hormone release and puberty in dairy heifers.

    PubMed

    Ringuet, H; Pelletier, G; Brazeau, P; Gaudreau, P; Guilbault, L A; Morisset, J; Couture, Y; Petitclerc, D

    1994-10-01

    Forty-eight Holstein dairy heifers (98.9 kg BW; 3 mo old) were subjected for 246 d to twice-daily s.c. injections of saline (CTL) or human growth hormone-releasing hormone (GRH; 5 micrograms/kg BW) and to photoperiods of 8 h of light (L): 16 h of dark (D) or 16L:8D according to a 2 x 2 factorial arrangement of treatments. Jugular blood samples were collected from 16 heifers at 3, 4, 8, and 11 mo of age to monitor prolactin, growth hormone, and estradiol-17 beta. Plasma progesterone concentrations were monitored weekly in all heifers as an index of puberty (> 1 ng/mL). Growth hormone release was induced by GRH (P < .001) throughout the trial; area under the GH curve (AUC) averaged 1,582 vs 3,643 ng.min-1.mL-1 in CTL vs GRH heifers. However, GRH-induced GH response was less (P < .05) after the second daily injection. There was also an interaction (P = .08) between GRH, photoperiod, and days of treatment on GRH-induced GH response; AUC was greater in GRH-16L:8D than in GRH-8L:16D heifers at 3 mo but less at 8 mo of age. The PRL concentrations were similar for both photoperiods at 3 mo (36.4 vs 41.7 ng/mL) and 8 mo (16.2 vs 12.8 ng/mL) of age but were greater in 16L:8D vs 8L:16D heifers at 4 mo (18.4 vs 39.3 ng/mL) and 11 mo (26.3 vs 44.1 ng/mL) of age (photoperiod x day interaction, P < .001). Photoperiod of 16L:8D vs 8L:16D reduced (P < .01) weight at puberty in CTL heifers (251 vs 303 kg BW) and to a lesser extent in GRH-treated heifers (271 vs 284 kg BW; GRH x photoperiod interaction, P = .10). In conclusion, GH response is maintained throughout 8 mo of GRH treatment, and a 16L:8D photoperiod will reduce age and weight at puberty in heifers. Furthermore, refractoriness to photoperiod-induced PRL changes was detected.

  2. Growth hormone-releasing hormone is produced by adipocytes and regulates lipolysis through growth hormone receptor.

    PubMed

    Rodríguez-Pacheco, F; Gutierrez-Repiso, C; García-Serrano, S; Ho-Plagaro, A; Gómez-Zumaquero, J M; Valdes, S; Gonzalo, M; Rivas-Becerra, J; Montiel-Casado, C; Rojo-Martínez, G; García-Escobar, E; García-Fuentes, E

    2017-10-01

    Growth hormone-releasing hormone (GHRH) has a crucial role in growth hormone (GH) secretion, but little is known about its production by adipocytes and its involvement in adipocyte metabolism. To determine whether GHRH and its receptor (GHRH-R) are present in human adipocytes and to study their levels in obesity. Also, to analyze the effects of GHRH on human adipocyte differentiation and lipolysis. GHRH/GHRH-R and GH/GH-R mRNA expression levels were analyzed in human mature adipocytes from non-obese and morbidly obese subjects. Human mesenchymal stem cells (HMSC) were differentiated to adipocytes with GHRH (10(-14)-10(-8) M). Adipocyte differentiation, lipolysis and gene expression were measured and the effect of GH-R silencing was determined. Mature adipocytes from morbidly obese subjects showed a higher expression of GHRH and GH-R, and a lower expression of GHRH-R and GH than non-obese subjects (P<0.05). A total of 10(-14)-10(-10) M GHRH induced an inhibition of lipid accumulation and PPAR-γ expression (P<0.05), and an increase in glycerol release and HSL expression (P<0.05) in human differentiated adipocytes. A total of 10(-12)-10(-8) M GHRH decreased GHRH-R expression in human differentiated adipocytes (P<0.05). A total of 10(-10)-10(-8) M GHRH increased GH and GH-R expression in human differentiated adipocytes (P<0.05). The effects of GHRH at 10(-10) M on adipocyte differentiation and lipolysis were blocked when GH-R expression was silenced. GHRH and GHRH-R are expressed in human adipocytes and are negatively associated. GHRH at low doses may exert an anti-obesity effect by inhibiting HMSC differentiation in adipocytes and by increasing adipocyte lipolysis in an autocrine or paracrine pathway. These effects are mediated by GH and GH-R.

  3. A potassium current evoked by growth hormone-releasing hormone in follicular oocytes of Xenopus laevis.

    PubMed Central

    Yoshida, S; Plant, S

    1991-01-01

    1. Electrophysiological properties of the growth hormone-releasing hormone (GRH) receptor were studied in Xenopus oocytes with an intact follicle cell layer (i.e. follicular oocytes) by measuring whole-cell current using the two-electrode voltage-clamp method. 2. A slow transient outward current was elicited in oocytes, clamped at -60 mV, by the application of rat GRH but not bovine, porcine, or human GRH. 3. The response to GRH was not suppressed by blockers known to inhibit other endogenous receptors present in follicular Xenopus oocytes; blockers used were timolol (2 microM; beta-adrenergic blocker), theophylline (0.1 mM; purinergic blocker) and atropine (100 nM; muscarinic blocker). 4. The current response evoked by rat GRH occurred in a dose-dependent manner. The concentrations of GRH for threshold and maximum responses were 1 and 100 nM respectively and the estimated EC50 (half-maximal effective concentration) was approximately 7 nM. The amplitude and conductance of the response became larger and the latency, time-to-peak and half-decay time were shortened when the concentration of GRH was increased. 5. The GRH response was reversibly inhibited by a K+ channel blocker, tetraethylammonium+ (TEA+; 20 mM). The reversal potential for the GRH response was around -100 mV and was compatible with the reported value for a K+ current in Xenopus oocytes. Furthermore, a depolarizing shift of 40 mV in the reversal potential was observed when the external K+ concentration was increased from 2 to 10 mM, agreeing with the Nernst equation. In contrast, no significant shift in the reversal potential was observed by changing the external concentration of Na+ or Cl-. 6. The GRH response was not suppressed in oocytes treated with an acetoxy-methyl ester of bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM; 10 microM) which penetrates the cell membrane and chelates internal Ca2+. 7. The GRH response was potentiated by pre-treatment with forskolin (0.4 microM; 5 min

  4. Growth Hormone-Releasing Hormone and Its Analogues: Significance for MSCs-Mediated Angiogenesis

    PubMed Central

    Tao, Quanwei; Ma, Qunchao; Chen, Huiqiang; Wang, Jian'an

    2016-01-01

    Mesenchymal stromal cells (MSCs) are promising candidates for regenerative medicine because of their multipotency, immune-privilege, and paracrine properties including the potential to promote angiogenesis. Accumulating evidence suggests that the inherent properties of cytoprotection and tissue repair by native MSCs can be enhanced by various preconditioning stimuli implemented prior to cell transplantation. Growth hormone-releasing hormone (GHRH), a stimulator in extrahypothalamus systems including tumors, has attracted great attentions in recent years because GHRH and its agonists could promote angiogenesis in various tissues. GHRH and its agonists are proangiogenic in responsive tissues including tumors, and GHRH antagonists have been tested as antitumor agents through their ability to suppress angiogenesis and cell growth. GHRH-R is expressed by MSCs and evolving work from our laboratory indicates that treatment of MSCs with GHRH agonists prior to cell transplantation markedly enhanced the angiogenic potential and tissue reparative properties of MSCs through a STAT3 signaling pathway. In this review we summarized the possible effects of GHRH analogues on cell growth and development, as well as on the proangiogenic properties of MSCs. We also discussed the relationship between GHRH analogues and MSC-mediated angiogenesis. The analyses provide new insights into molecular pathways of MSCs-based therapies and their augmentation by GHRH analogues. PMID:27774107

  5. Growth hormone-releasing hormone disruption extends lifespan and regulates response to caloric restriction in mice

    PubMed Central

    Sun, Liou Y; Spong, Adam; Swindell, William R; Fang, Yimin; Hill, Cristal; Huber, Joshua A; Boehm, Jacob D; Westbrook, Reyhan; Salvatori, Roberto; Bartke, Andrzej

    2013-01-01

    We examine the impact of targeted disruption of growth hormone-releasing hormone (GHRH) in mice on longevity and the putative mechanisms of delayed aging. GHRH knockout mice are remarkably long-lived, exhibiting major shifts in the expression of genes related to xenobiotic detoxification, stress resistance, and insulin signaling. These mutant mice also have increased adiponectin levels and alterations in glucose homeostasis consistent with the removal of the counter-insulin effects of growth hormone. While these effects overlap with those of caloric restriction, we show that the effects of caloric restriction (CR) and the GHRH mutation are additive, with lifespan of GHRH-KO mutants further increased by CR. We conclude that GHRH-KO mice feature perturbations in a network of signaling pathways related to stress resistance, metabolic control and inflammation, and therefore provide a new model that can be used to explore links between GHRH repression, downregulation of the somatotropic axis, and extended longevity. DOI: http://dx.doi.org/10.7554/eLife.01098.001 PMID:24175087

  6. Structural and functional divergence of growth hormone-releasing hormone receptors in early sarcopterygians: lungfish and Xenopus.

    PubMed

    Tam, Janice K V; Chow, Billy K C; Lee, Leo T O

    2013-01-01

    The evolutionary trajectories of growth hormone-releasing hormone (GHRH) receptor remain enigmatic since the discovery of physiologically functional GHRH-GHRH receptor (GHRHR) in non-mammalian vertebrates in 2007. Interestingly, subsequent studies have described the identification of a GHRHR(2) in chicken in addition to the GHRHR and the closely related paralogous receptor, PACAP-related peptide (PRP) receptor (PRPR). In this article, we provide information, for the first time, on the GHRHR in sarcopterygian fish and amphibians by the cloning and characterization of GHRHRs from lungfish (P. dolloi) and X. laevis. Sequence alignment and phylogenetic analyses demonstrated structural resemblance of lungfish GHRHR to their mammalian orthologs, while the X. laevis GHRHR showed the highest homology to GHRHR(2) in zebrafish and chicken. Functionally, lungfish GHRHR displayed high affinity towards GHRH in triggering intracellular cAMP and calcium accumulation, while X. laevis GHRHR(2) was able to react with both endogenous GHRH and PRP. Tissue distribution analyses showed that both lungfish GHRHR and X. laevis GHRHR(2) had the highest expression in brain, and interestingly, X. laevis(GHRHR2) also had high abundance in the reproductive organs. These findings, together with previous reports, suggest that early in the Sarcopterygii lineage, GHRHR and PRPR have already established diverged and specific affinities towards their cognate ligands. GHRHR(2), which has only been found in xenopus, zebrafish and chicken hitherto, accommodates both GHRH and PRP.

  7. Structural and Functional Divergence of Growth Hormone-Releasing Hormone Receptors in Early Sarcopterygians: Lungfish and Xenopus

    PubMed Central

    Tam, Janice K. V.; Chow, Billy K. C.; Lee, Leo T. O.

    2013-01-01

    The evolutionary trajectories of growth hormone-releasing hormone (GHRH) receptor remain enigmatic since the discovery of physiologically functional GHRH-GHRH receptor (GHRHR) in non-mammalian vertebrates in 2007. Interestingly, subsequent studies have described the identification of a GHRHR2 in chicken in addition to the GHRHR and the closely related paralogous receptor, PACAP-related peptide (PRP) receptor (PRPR). In this article, we provide information, for the first time, on the GHRHR in sarcopterygian fish and amphibians by the cloning and characterization of GHRHRs from lungfish (P. dolloi) and X. laevis. Sequence alignment and phylogenetic analyses demonstrated structural resemblance of lungfish GHRHR to their mammalian orthologs, while the X. laevis GHRHR showed the highest homology to GHRHR2 in zebrafish and chicken. Functionally, lungfish GHRHR displayed high affinity towards GHRH in triggering intracellular cAMP and calcium accumulation, while X. laevis GHRHR2 was able to react with both endogenous GHRH and PRP. Tissue distribution analyses showed that both lungfish GHRHR and X. laevis GHRHR2 had the highest expression in brain, and interestingly, X. laevis GHRHR2 also had high abundance in the reproductive organs. These findings, together with previous reports, suggest that early in the Sarcopterygii lineage, GHRHR and PRPR have already established diverged and specific affinities towards their cognate ligands. GHRHR2, which has only been found in xenopus, zebrafish and chicken hitherto, accommodates both GHRH and PRP. PMID:23308232

  8. Mouse hypothalamic growth hormone-releasing hormone and somatostatin responses to probes of signal transduction systems.

    PubMed

    Sato, M; Downs, T R; Frohman, L A

    1993-01-01

    Signal transduction mechanisms involved in mouse growth hormone-releasing hormone (GRH) and somatostatin (SRIH) release were investigated using an in vitro perifusion system. Hypothalamic fragments were exposed to depolarizing agents, protein kinase A and C activators, and a calcium ionophore. The depolarizing agents, KCl (60 mM) and veratridine (50 microM), induced similar patterns of GRH and SRIH release. Somatostatin release in response to both agents was twofold greater than that of GRH. Forskolin (10 microM and 100 microM), an adenylate cyclase activator, stimulated both GRH and SRIH release, though with different secretory profiles. The SRIH response was prolonged and persisted beyond removal of the drug from the system, while the GRH response was brief, ending even prior to forskolin removal. Neither GRH nor SRIH were stimulated by 1,9-dideoxy-forskolin (100 microM), a forskolin analog with cAMP-independent actions. A23187 (5 microM), a calcium ionophore, stimulated the release of SRIH to a much greater extent than that of GRH. The GRH and SRIH secretory responses to PMA (1 microM), a protein kinase C activator, were similar, though delayed. The results suggest that 1) GRH and SRIH secretion are regulated by both protein kinase A and C pathways, and 2) depolarizing agents are important for the release of both hormones.

  9. Hormonal and lactational responses to growth hormone-releasing hormone treatment in lactating Japanese Black cows.

    PubMed

    Shingu, H; Hodate, K; Kushibiki, S; Ueda, Y; Touno, E; Shinoda, M; Ohashi, S

    2004-06-01

    Ten multiparous lactating Japanese Black cows (beef breed) were used to evaluate the effects of bovine growth hormone-releasing hormone (GHRH) analog on milk yield and profiles of plasma hormones and metabolites. The cows received 2 consecutive 21-d treatments (a daily s.c. injection of 3-mg GHRH analog or saline) in a 2 (group) x 2 (period) Latin square crossover design. The 5 cows in group A received GHRH analog during period 1 (from d 22 to 42 postpartum) and saline during period 2 (from d 57 to 77 postpartum), and those in group B received saline and GHRH analog during periods 1 and 2, respectively. Mean milk yield decreased in saline treated compared with that during the 1-wk period before treatment 7.4 and 19.1% during periods 1 (group B) and 2 (group A), respectively. Treatment with GHRH analog increased milk yield 17.4% (period 1, group A) and 6.3% (period 2, group B). Treatment with GHRH analog induced higher basal plasma concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin, and glucose compared with saline-treated cows. In glucose challenge, the GHRH analog-treated beef cows had greater insulin secretion than the saline-treated beef cows. In insulin challenge, however, there were no significant differences in the areas surrounded by hypothetical lines of basal glucose concentrations and glucose response curves between GHRH analog- and saline-treated cows. These results demonstrate that GHRH analog treatment facilitates endogenous GH secretion in lactating Japanese Black cows, leading to increases in milk yield and plasma concentrations of IGF-1, insulin, and glucose.

  10. Potentiation of cytotoxic chemotherapy by growth hormone-releasing hormone agonists

    PubMed Central

    Jaszberenyi, Miklos; Rick, Ferenc G.; Popovics, Petra; Block, Norman L.; Zarandi, Marta; Cai, Ren-Zhi; Vidaurre, Irving; Szalontay, Luca; Jayakumar, Arumugam R.; Schally, Andrew V.

    2014-01-01

    The dismal prognosis of malignant brain tumors drives the development of new treatment modalities. In view of the multiple activities of growth hormone-releasing hormone (GHRH), we hypothesized that pretreatment with a GHRH agonist, JI-34, might increase the susceptibility of U-87 MG glioblastoma multiforme (GBM) cells to subsequent treatment with the cytotoxic drug, doxorubicin (DOX). This concept was corroborated by our findings, in vivo, showing that the combination of the GHRH agonist, JI-34, and DOX inhibited the growth of GBM tumors, transplanted into nude mice, more than DOX alone. In vitro, the pretreatment of GBM cells with JI-34 potentiated inhibitory effects of DOX on cell proliferation, diminished cell size and viability, and promoted apoptotic processes, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide proliferation assay, ApoLive-Glo multiplex assay, and cell volumetric assay. Proteomic studies further revealed that the pretreatment with GHRH agonist evoked differentiation decreasing the expression of the neuroectodermal stem cell antigen, nestin, and up-regulating the glial maturation marker, GFAP. The GHRH agonist also reduced the release of humoral regulators of glial growth, such as FGF basic and TGFβ. Proteomic and gene-expression (RT-PCR) studies confirmed the strong proapoptotic activity (increase in p53, decrease in v-myc and Bcl-2) and anti-invasive potential (decrease in integrin α3) of the combination of GHRH agonist and DOX. These findings indicate that the GHRH agonists can potentiate the anticancer activity of the traditional chemotherapeutic drug, DOX, by multiple mechanisms including the induction of differentiation of cancer cells. PMID:24379381

  11. Acceleration of wound healing by growth hormone-releasing hormone and its agonists.

    PubMed

    Dioufa, Nikolina; Schally, Andrew V; Chatzistamou, Ioulia; Moustou, Evi; Block, Norman L; Owens, Gary K; Papavassiliou, Athanasios G; Kiaris, Hippokratis

    2010-10-26

    Despite the well-documented action of growth hormone-releasing hormone (GHRH) on the stimulation of production and release of growth hormone (GH), the effects of GHRH in peripheral tissues are incompletely explored. In this study, we show that GHRH plays a role in wound healing and tissue repair by acting primarily on wound-associated fibroblasts. Mouse embryonic fibroblasts (MEFs) in culture and wound-associated fibroblasts in mice expressed a splice variant of the receptors for GHRH (SV1). Exposure of MEFs to 100 nM and 500 nM GHRH or the GHRH agonist JI-38 stimulated the expression of α-smooth muscle actin (αSMA) based on immunoblot analyses as well as the expression of an αSMA-β-galactosidase reporter transgene in primary cultures of fibroblasts isolated from transgenic mice. Consistent with this induction of αSMA expression, results of transwell-based migration assays and in vitro wound healing (scratch) assays showed that both GHRH and GHRH agonist JI-38 stimulated the migration of MEFs in vitro. In vivo, local application of GHRH or JI-38 accelerated healing in skin wounds of mice. Histological evaluation of skin biopsies showed that wounds treated with GHRH and JI-38 were both characterized by increased abundance of fibroblasts during the early stages of wound healing and accelerated reformation of the covering epithelium at later stages. These results identify another function of GHRH in promoting skin tissue wound healing and repair. Our findings suggest that GHRH may have clinical utility for augmenting healing of skin wounds resulting from trauma, surgery, or disease.

  12. Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs

    NASA Technical Reports Server (NTRS)

    Draghia-Akli, R.; Fiorotto, M. L.; Hill, L. A.; Malone, P. B.; Deaver, D. R.; Schwartz, R. J.

    1999-01-01

    Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

  13. Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs

    NASA Technical Reports Server (NTRS)

    Draghia-Akli, R.; Fiorotto, M. L.; Hill, L. A.; Malone, P. B.; Deaver, D. R.; Schwartz, R. J.

    1999-01-01

    Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

  14. Changes of growth hormone-releasing hormone and somatostatin neurons in the rat hypothalamus induced by genistein: a stereological study.

    PubMed

    Trifunović, Svetlana; Manojlović-Stojanoski, Milica; Ristić, Nataša; Nestorović, Nataša; Medigović, Ivana; Živanović, Jasmina; Milošević, Verica

    2016-12-01

    Genistein is a plant-derived estrogenic isoflavone commonly found in dietary and therapeutic supplements, due to its potential health benefits. Growth hormone-releasing hormone (GHRH) and somatostatin (SS) are neurosecretory peptides synthesized in neurons of the hypothalamus and regulate the growth hormone secretion. Early reports indicate that estrogens have highly involved in the regulation of GHRH and SS secretions. Since little is known about the potential effects of genistein on GHRH and SS neurons, we exposed rats to genistein. Genistein were administered to adult rats in dose of 30 mg/kg, for 3 weeks. The estradiol-dipropionate treatment was used as the adequate controls to genistein. Using applied stereology on histological sections of hypothalamus, we obtained the quantitative information on arcuate (Arc) and periventricular (Pe) nucleus volume and volume density of GHRH neurons and SS neurons. Image analyses were used to obtain GHRH and SS contents in the median eminence (ME). Administration of estradiol-dipropionate caused the increase of Arc and Pe nucleus volume, SS neuron volume density, GHRH and SS staining intensity in the ME, when compared with control. Genistein treatment increased: Arc nucleus volume and the volume density of GHRH neurons (by 26%) and SS neurons (1.5 fold), accompanied by higher GHRH and SS staining intensity in the ME, when compared to the orhidectomized group. These results suggest that genistein has a significant effect on hypothalamic region, involved in the regulation of somatotropic system function, and could contribute to the understanding of genistein as substance that alter the hormonal balance.

  15. Growth hormone secretion from chicken adenohypophyseal cells in primary culture: effects of human pancreatic growth hormone-releasing factor, thyrotropin-releasing hormone, and somatostatin on growth hormone release.

    PubMed

    Perez, F M; Malamed, S; Scanes, C G

    1987-03-01

    A primary culture of chicken adenohypophyseal cells has been developed to study the regulation of growth hormone (GH) secretion. Following collagenase dispersion, cells were exposed for 2 hr to vehicle (control) or test agents. Human pancreatic (tumor) growth hormone-releasing factor (hpGRF) and rat hypothalamic growth hormone-releasing factor stimulated GH release to similar levels. GH release was increased by the presence of dibutyryl cyclic AMP. Thyrotropin-releasing hormone (TRH) alone did not influence GH release; however, TRH plus hpGRF together exerted a synergistic (greater than additive) effect, increasing GH release by 100 to 300% over the sum of the values for each secretagogue acting alone. These relationships between TRH and hpGRF were further examined in cultured cells exposed to secretagogues for two consecutive 2-hr incubations. TRH pretreatment enhanced subsequent hpGRF-stimulated GH release by about 80% over that obtained if no secretagogue was present during the first incubation. In other experiments, somatostatin (SRIF) alone did not alter GH secretion. However, SRIF reduced hpGRF-stimulated GH release to levels found in controls. Furthermore, GH release stimulated by the presence of both TRH and hpGRF was lowered to control values by SRIF. The results of these studies demonstrate that a primary culture of chicken adenohypophyseal cells is a useful model for the study of GH secretion. Indeed, these results suggest that TRH and hpGRF regulate GH secretion by mechanisms which are not identical.

  16. Metastatic Pancreatic Neuroendocrine Tumor that Progressed to Ectopic Adrenocorticotropic Hormone (ACTH) Syndrome with Growth Hormone-releasing Hormone (GHRH) Production

    PubMed Central

    Tadokoro, Rie; Sato, Shotaro; Otsuka, Fumiko; Ueno, Makoto; Ohkawa, Shinichi; Katakami, Hideki; Taniyama, Matsuo; Nagasaka, Shoichiro

    2016-01-01

    The patient was a 61-year-old woman who had a well-differentiated pancreatic neuroendocrine tumor (PNET) with lymph node metastasis. After 15 months of octreotide treatment, glucose control deteriorated and pigmentation of the tongue and moon face developed, leading to the diagnosis of ectopic adrenocorticotropic hormone (ACTH) syndrome. An abnormal secretion of growth hormone (GH) was identified, and the plasma growth hormone-releasing hormone (GHRH) level was elevated. A tumor biopsy specimen positively immunostained for ACTH and GHRH. Ectopic hormone secretion seems to have evolved along with the progression of the PNET. PMID:27746436

  17. Metastatic Pancreatic Neuroendocrine Tumor that Progressed to Ectopic Adrenocorticotropic Hormone (ACTH) Syndrome with Growth Hormone-releasing Hormone (GHRH) Production.

    PubMed

    Tadokoro, Rie; Sato, Shotaro; Otsuka, Fumiko; Ueno, Makoto; Ohkawa, Shinichi; Katakami, Hideki; Taniyama, Matsuo; Nagasaka, Shoichiro

    The patient was a 61-year-old woman who had a well-differentiated pancreatic neuroendocrine tumor (PNET) with lymph node metastasis. After 15 months of octreotide treatment, glucose control deteriorated and pigmentation of the tongue and moon face developed, leading to the diagnosis of ectopic adrenocorticotropic hormone (ACTH) syndrome. An abnormal secretion of growth hormone (GH) was identified, and the plasma growth hormone-releasing hormone (GHRH) level was elevated. A tumor biopsy specimen positively immunostained for ACTH and GHRH. Ectopic hormone secretion seems to have evolved along with the progression of the PNET.

  18. Growth hormone release induced by growth hormone-releasing hexapeptide is not mediated by thyrotropin-releasing hormone in neonatal rats.

    PubMed

    Kacsóh, B; Kacsóh, G; Guzzardo, M B; Black, A C; Bisat, T

    1997-02-01

    GH-releasing hexapeptide (GHRP-6) and nursing stimulate GH secretion in rat pups via GH-releasing factors (GRFs: distinct from GH-releasing hormone (GHRH). It was determined whether GH secretion induced by GHRP-6 or nursing was mediated by TSH-releasing hormone (TRH) in 2-d-old rats. In vitro. GHRP-6 and TRH stimulated GH secretion of neonatal pituitary glands. At their maximally effective doses, GHRP-6 and TRH evoked approximately equal GH responses. Treatment with a combination of the maximally effective doses of GHRP-6 and TRH resulted in a GH response comparable to that evoked by either treatment alone. GHRP-6 in vivo induced a greater GH response than did TRH. Treatment in vivo with a combination of the maximally effective doses of GHRP-6 and TRH synergistically increased serum GH levels. Unlike GHRP-6 TRH was an effective stimulus of prolactin secretion either in vitro or in vivo. Nursing was an effective stimulus for GH secretion, but only marginally increased serum prolactin levels. The effects of either of the peptides and nursing on GH secretion were additive. These results suggest that GHRP-6 stimulates GH secretion both by acting directly on the pituitary gland and indirectly via a hypothalamic GRF. The indirect effect appears to be greater. The alternative GRFs released by GHRP-6 or nursing are distinct from each other and from TRH. These findings suggest that alternative GRFs play a significant role in the regulation of GH secretion in neonatal rats.

  19. Puberty, statural growth, and growth hormone release in children with cerebral palsy

    PubMed Central

    Kuperminc, Michelle N.; Gurka, Matthew J.; Houlihan, Christine M.; Henderson, Richard C.; Roemmich, James N.; Rogol, Alan D.

    2010-01-01

    Objective Children with cerebral palsy (CP) are smaller than normally growing children.. The association between the growth hormone (GH) axis and growth in children with CP during puberty is unknown. We compared growth and markers of the GH axis in pre-pubertal and pubertal children with moderate to severe CP and without CP over a three-year period. Study design Twenty children with CP, ages 6–18, Gross Motor Function Classification System levels III–V, were compared to a group of sixty-three normally growing children of similar age. Anthropometry, Tanner stage, bone age, and laboratory analyses were performed every six months for three years. Laboratory values included spontaneous overnight GH release, fasting IGF-1 and IGFBP-3. Repeated measures models were used to evaluate interactions among Tanner stage and group (children with CP vs. reference children), taking into account gender, age, and nutritional status. Results Children with CP grew more slowly than those without CP at all Tanner stages (p<0.01). Patterns of IGF-1 and GH secretion in children with CP were similar to those of the reference group; however, the concentrations of IGF-1 (p<0.01) and GH (p<0.01) were lower in girls with CP, with a similar trend for boys (p=0.10 and 0.14, respectively). Conclusions Diminished circulating IGF-1 and GH concentrations may explain the differences in growth between the two groups. PMID:20216931

  20. Antagonists of growth hormone-releasing hormone suppress in vivo tumor growth and gene expression in triple negative breast cancers.

    PubMed

    Perez, Roberto; Schally, Andrew V; Vidaurre, Irving; Rincon, Ricardo; Block, Norman L; Rick, Ferenc G

    2012-09-01

    This study evaluated the effects of a modern antagonistic analog of GHRH on tumor growth and on expression of inflammatory cytokine genes in two models of human triple negative breast cancers (TNBC). The TNBC subtype is refractory to the treatment options available for other hormone-independent breast cancers. Inflammatory cytokines play a major role in the cellular signaling associated with breast cancer pathogenesis and enhance epithelial-mesenchymal transitions (EMT), drug resistance, and metastatic potential. Growth hormone-releasing hormone (GHRH) is a hypothalamic neuropeptide which regulates the synthesis and release of growth hormone by the pituitary and is an autocrine/paracrine growth factor for multiple human cancers. The effects of analogs of GHRH on tumoral cytokine expression have not been previously investigated. Animals bearing xenografts of the human TNBC cell lines, HCC1806 and MX-1, were treated with MIA-602, an antagonistic analog of GHRH. Treatment with MIA-602 significantly reduced tumor growth. We quantified transcript levels of the genes for several inflammatory cytokines. Expression of INFγ, IL-1α, IL-4, IL-6, IL-8, IL-10, and TNFα, was significantly reduced by treatment with MIA-602. We conclude that treatment of TNBC with GHRH antagonists reduces tumor growth through an action mediated by tumoral GHRH receptors and produces a suppression of inflammatory cytokine signaling. Silencing of GHRH receptors in vitro with siRNA inhibited the expression of GHRH-R genes and inflammatory cytokine genes in HCC1806 and MX-1 cells. Further studies on GHRH antagonists may facilitate the development of new strategies for the treatment of resistant cancers.

  1. Understanding the multifactorial control of growth hormone release by somatotropes: lessons from comparative endocrinology.

    PubMed

    Gahete, Manuel D; Durán-Prado, Mario; Luque, Raúl M; Martínez-Fuentes, Antonio J; Quintero, Ana; Gutiérrez-Pascual, Ester; Córdoba-Chacón, José; Malagón, María M; Gracia-Navarro, Francisco; Castaño, Justo P

    2009-04-01

    Control of postnatal growth is the main, but not the only, role for growth hormone (GH) as this hormone also contributes to regulating metabolism, reproduction, immunity, development, and osmoregulation in different species. Likely owing to this variety of group-specific functions, GH production is differentially regulated across vertebrates, with an apparent evolutionary trend to simplification, especially in the number of stimulatory factors governing substantially GH release. Thus, teleosts exhibit a multifactorial regulation of GH secretion, with a number of factors, from the newly discovered fish GH-releasing hormone (GHRH) to pituitary adenylate cyclase-activating peptide (PACAP) but also gonadotropin-releasing hormone, dopamine, corticotropin-releasing hormone, and somatostatin(s) directly controlling somatotropes. In amphibians and reptiles, GH secretion is primarily stimulated by the major hypothalamic peptides GHRH and PACAP and inhibited by somatostatin(s), while other factors (ghrelin, thyrotropin-releasing hormone) also influence GH release. Finally, in birds and mammals, primary control of GH secretion is exerted by a dual interplay between GHRH and somatostatin. In addition, somatotrope function is modulated by additional hypothalamic and peripheral factors (e.g., ghrelin, leptin, insulin-like growth factor-I), which together enable a balanced integration of feedback signals related to processes in which GH plays a relevant regulatory role, such as metabolic and energy status, reproductive, and immune function. Interestingly, in contrast to the high number of stimulatory factors impinging upon somatotropes, somatostatin(s) stand(s) as the main primary inhibitory regulator(s) for this cell type.

  2. Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6).

    PubMed

    Micic, D; Mallo, F; Peino, R; Cordido, F; Leal-Cerro, A; Garcia-Mayor, R V; Casanueva, F F

    1993-01-01

    Growth hormone (GH) secretion is regulated by a complex system of central and peripheral signals. Recently, a new GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) called GHRP-6 which specifically releases GH has been studied. In the present work the mechanism of action of GHRP-6 has been addressed in experimental animal models as well as in obese subjects. GHRP-6 releases GH independently of the hypothalamic factors GHRH and somatostatin and is a powerful GH releaser in obesity.

  3. Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release.

    PubMed Central

    Hartman, M L; Pincus, S M; Johnson, M L; Matthews, D H; Faunt, L M; Vance, M L; Thorner, M O; Veldhuis, J D

    1994-01-01

    Pulses of growth hormone (GH) release in acromegaly may arise from hypothalamic regulation or from random events intrinsic to adenomatous tissue. To distinguish between these possibilities, serum GH concentrations were measured at 5-min intervals for 24 h in acromegalic men and women with active (n = 19) and inactive (n = 9) disease and in normal young adults in the fed (n = 20) and fasted (n = 16) states. Daily GH secretion rates, calculated by deconvolution analysis, were greater in patients with active acromegaly than in fed (P < 0.05) but not fasted normal subjects. Significant basal (nonpulsatile) GH secretion was present in virtually all active acromegalics but not those in remission or in fed and fasted normal subjects. A recently introduced scale- and model-independent statistic, approximate entropy (ApEn), was used to test for regularity (orderliness) in the GH data. All but one acromegalic had ApEn values greater than the absolute range in normal subjects, indicating reduced orderliness of GH release; ApEn distinguished acromegalic from normal GH secretion (fed, P < 10(-12); fasted, P < 10(-7)) with high sensitivity (95%) and specificity (100%). Acromegalics in remission had ApEn scores larger than those of normal subjects (P < 0.0001) but smaller than those of active acromegalics (P < 0.001). The coefficient of variation of successive incremental changes in GH concentrations was significantly lower in acromegalics than in normal subjects (P < 0.001). Fourier analysis in acromegalics revealed reduced fractional amplitudes compared to normal subjects (P < 0.05). We conclude that GH secretion in acromegaly is highly irregular with disorderly release accompanying significant basal secretion. Images PMID:8083369

  4. Determination of growth hormone-releasing hexapeptide by reversed-phase high-performance liquid chromatography with electrochemical detection.

    PubMed

    Choi, S J; Lee, H Y; Kim, S B; Kim, J H; Lee, S S; Yoo, S D; Lee, K C; Lee, H S

    2001-04-25

    A novel HPLC method with electrochemical detection is described for the determination of a growth-hormone-releasing hexapeptide (GHRP-6). HPLC conditions, such as the column, mobile phase, and oxidation potential, were optimized for sensitivity and selectivity of analysis. GHRP-6 was separated on a reversed-phase CN column with 37% acetonitrile in 100 mM phosphate buffer (pH 7.0) as the mobile phase. The optimum electrochemical oxidation signal was obtained at 0.85 V vs. Ag/AgCl in a glassy carbon working electrode due to two electroactive tryptophans and a histidine residue. Solid-phase extraction using octadecyl cartridges was optimized for sample cleanup of GHRP-6 from serum samples and the method was successfully applied over the concentration range of 5 to 100 ng/ml of analyte. reserved.

  5. Intestinal peptides as circulating hormones: release of tachykinin-related peptide from the locust and cockroach midgut.

    PubMed

    Winther, A M; Nässel, D R

    2001-04-01

    Tachykinin-related peptides (TRPs) in the locust Locusta migratoria and the cockroach Leucophaea maderae have stimulatory effects on some muscles that are not innervated by TRP-containing neurons. Thus, these tissues may be affected by circulating TRPs. Here, we have investigated whether the midgut is the source of circulating TRPs. TRP-immunoreactive material in the locust midgut is found only in the endocrine cells of the gut epithelium. In both species of insect, the endocrine cells contain several isoforms of TRPs, as determined by immunocytochemistry and a combination of chromatography (HPLC) and enzyme immunoassay (ELISA). The release of TRPs was investigated by ELISA using isolated midguts of the locust and cockroach. Elevated levels of K(+) in the bathing saline induced the release of TRP from the midgut of both species. To examine the release of TRPs into the circulation in vivo, we measured haemolymph levels of TRPs in fed and starved locusts. The concentration of TRP-immunoreactive material in fed locusts was estimated to be 0.15 nmol l(-1), and this increased approximately fourfold in insects starved for 24 h. In accordance with this observation, the content of TRP-immunoreactive material in the midgut was lower in starved locusts than in fed locusts. Although part of the increased blood concentration of TRPs may be due to reduced blood volume, our data suggest that TRPs are released as hormones from the midgut of the locust and cockroach and that this release may be linked to nutritional status.

  6. A 66-bp deletion in growth hormone releasing hormone gene 5'-flanking region with largemouth bass recessive embryonic lethal.

    PubMed

    Ma, D M; Han, L Q; Bai, J J; Li, S J; Fan, J J; Yu, L Y; Quan, Y C

    2014-06-01

    Growth hormone releasing hormone (GHRH) regulates the secretion of growth hormone (GH) in the pituitary gland. A 66-bp deletion (c.-923_-858del) was detected in the 5'-flanking sequence of the largemouth bass (Micropterus salmoides) GHRH gene. In two cultured random populations of adult individuals (A: n = 170 and B: n = 150), the genotype ratios of +/+:+/- were 2.5:1 and 2.8:1 respectively. Only one -/- fish was detected. A Largemouth bass family was constructed with two heterozygous individuals (+/-) as parents. The genotype ratio of +/+:+/-:-/- in the filial generation embryos was 1:1.6:0.1 at the neurula and 1:2:0 at hatched larvae stages. This indicated that the 66-bp deletion was a recessive lethal site and that homozygous individuals (-/-) died off in embryonic development. The growth traits (body weight, body length and body depth) were measured, and the GHRH mRNA expression levels in brain tissue were detected using real-time PCR. The effects of genotype (+/-) on growth traits and GHRH mRNA expression were not significant. Although the cause of death was not clear, the results hint that the 66-bp deletion site in GHRH 5'-flanking sequence significantly affects the livability in largemouth bass embryonic development.

  7. A Role for Central Nervous Growth Hormone-Releasing Hormone Signaling in the Consolidation of Declarative Memories

    PubMed Central

    Michel, Christian; Perras, Boris; Born, Jan

    2011-01-01

    Contributions of somatotropic hormonal activity to memory functions in humans, which are suggested by clinical observations, have not been systematically examined. With previous experiments precluding a direct effect of systemic growth hormone (GH) on acute memory formation, we assessed the role of central nervous somatotropic signaling in declarative memory consolidation. We examined the effect of intranasally administered growth hormone releasing-hormone (GHRH; 600 µg) that has direct access to the brain and suppresses endogenous GHRH via an ultra-short negative feedback loop. Twelve healthy young men learned word-pair associates at 2030 h and were administered GHRH and placebo, respectively, at 2100 h. Retrieval was tested after 11 hours of wakefulness. Compared to placebo, intranasal GHRH blunted GH release within 3 hours after substance administration and reduced the number of correctly recalled word-pairs by ∼12% (both P<0.05). The impairment of declarative memory consolidation was directly correlated to diminished GH concentrations (P<0.05). Procedural memory consolidation as examined by the parallel assessment of finger sequence tapping performance was not affected by GHRH administration. Our findings indicate that intranasal GHRH, by counteracting endogenous GHRH release, impairs hippocampal memory processing. They provide first evidence for a critical contribution of central nervous somatotropic activity to hippocampus-dependent memory consolidation. PMID:21850272

  8. Prolactin, thyrotropin, and growth hormone release during stress associated with parachute jumping.

    PubMed

    Noel, G L; Dimond, R C; Earll, J M; Frantz, A G

    1976-05-01

    Prolactin, growth hormone, and thyrotropin (TSH) release during the stress of parachute jumping has been evaluated in 14 male subjects. Subjects were studied at several times before and immediately after their first military parachute jump. All three hormones had risen significantly 1 to 14 min after the jump, compared to mean levels measured immediately beforehand. Earlier studies of physical exercise by ourselves and others would suggest that emotional stress played a role in producing changes of this magnitude. We conclude that prolactin, TSH, and growth hormone are released in physiologically significant amounts in association with the stress of parachute jumping.

  9. Growth hormone-releasing hormone (GHRH) antagonists inhibit the proliferation of androgen-dependent and -independent prostate cancers

    PubMed Central

    Letsch, Markus; Schally, Andrew V.; Busto, Rebeca; Bajo, Ana M.; Varga, Jozsef L.

    2003-01-01

    The antiproliferative effects of an antagonist of growth hormone-releasing hormone (GHRH) JV-1-38 were evaluated in nude mice bearing s.c. xenografts of LNCaP and MDA-PCa-2b human androgen-sensitive and DU-145 androgen-independent prostate cancers. In the androgen-sensitive models, JV-1-38 greatly potentiated the antitumor effect of androgen deprivation induced by surgical castration, but was ineffective when given alone. Thus, in castrated animals bearing MDA-PCa-2b cancers, the administration of JV-1-38 for 35 days virtually arrested tumor growth (94% inhibition vs. intact control, P < 0.01; and 75% vs. castrated control, P < 0.05). The growth of LNCaP tumors was also powerfully suppressed by JV-1-38 combined with castration (83% inhibition vs. intact control, P < 0.01; and 68% vs. castrated control, P < 0.05). However, in androgen-independent DU-145 cancers, JV-1-38 alone could inhibit tumor growth by 57% (P < 0.05) after 45 days. In animals bearing MDA-PCa-2b and LNCaP tumors, the reduction in serum prostate-specific antigen levels, after therapy with JV-1-38, paralleled the decrease in tumor volume. Inhibition of MDA-PCa-2b and DU-145 cancers was associated with the reduction in the expression of mRNA and protein levels of vascular endothelial growth factor. The mRNA expression for GHRH receptor splice variants was found in all these models of prostate cancer. Our results demonstrate that GHRH antagonists inhibit androgen-independent prostate cancers and, after combination with androgen deprivation, also androgen-sensitive tumors. Thus, the therapy with GHRH antagonist could be considered for the management of both androgen-dependent or -independent prostate cancers. PMID:12538852

  10. 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

  11. Neither bovine somatotropin nor growth hormone-releasing factor alters expression of thyroid hormone receptors in liver and mammary tissues.

    PubMed

    Capuco, A V; Binelli, M; Tucker, H A

    2011-10-01

    Physiological effects of thyroid hormones are mediated primarily by binding of triiodothyronine to specific nuclear receptors. Organ-specific changes in production of triiodothyronine from its prohormone, thyroxine, have been hypothesized to target the action of thyroid hormones on the mammary gland and play a role in mediating or augmenting a galactopoietic response to bovine somatotropin (bST). Additionally, tissue responsiveness to thyroid hormones may be altered by changes in the number or affinity of nuclear receptors for thyroid hormones. In the present study, effects of bST and bovine growth hormone-releasing factor (bGRF) on thyroid hormone receptors in liver and mammary gland were studied. Lactating Holstein cows received continuous infusions of bST or bGRF for 63 d or served as uninfused controls. Nuclei were isolated from harvested mammary and liver tissues and incubated with [(125)I]-triiodothyronine. Treatments did not alter the capacity or affinity of specific binding sites for triiodothyronine in liver or mammary nuclei. Evaluation of transcript abundance for thyroid hormone receptors showed that isoforms of thyroid hormone receptor or retinoid receptor (which may influence thyroid receptor action) expressed in the mammary gland were not altered by bST or bGRF treatment. Data do not support the hypothesis that administration of bST or bGRF alters sensitivity of mammary tissue by changing expression of thyroid hormone receptors.

  12. Growth hormone releasing hormone (GHRH) signaling modulates intermittent hypoxia-induced oxidative stress and cognitive deficits in mouse.

    PubMed

    Nair, Deepti; Ramesh, Vijay; Li, Richard C; Schally, Andrew V; Gozal, David

    2013-11-01

    Intermittent hypoxia (IH) during sleep, such as occurs in obstructive sleep apnea (OSA), leads to degenerative changes in the hippocampus, and is associated with spatial learning deficits in adult mice. In both patients and murine models of OSA, the disease is associated with suppression of growth hormone (GH) secretion, which is actively involved in the growth, development, and function of the central nervous system (CNS). Recent work showed that exogenous GH therapy attenuated neurocognitive deficits elicited by IH during sleep in rats. Here, we show that administration of the Growth Hormone Releasing Hormone (GHRH) agonist JI-34 attenuates IH-induced neurocognitive deficits, anxiety, and depression in mice along with reduction in oxidative stress markers such as MDA and 8-hydroxydeoxyguanosine, and increases in hypoxia inducible factor-1α DNA binding and up-regulation of insulin growth factor-1 and erythropoietin expression. In contrast, treatment with a GHRH antagonist (MIA-602) during intermittent hypoxia did not affect any of the IH-induced deleterious effects in mice. Thus, exogenous GHRH administered as the formulation of a GHRH agonist may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from OSA-associated neurocognitive dysfunction. Sleep apnea, characterized by chronic intermittent hypoxia (IH), is associated with substantial cognitive and behavioral deficits. Here, we show that administration of a GHRH agonist (JI-34) reduces oxidative stress, increases both HIF-1α nuclear binding and downstream expression of IGF1 and erythropoietin (EPO) in hippocampus and cortex, and markedly attenuates water maze performance deficits in mice exposed to intermittent hypoxia during sleep.

  13. Cerebral hypoperfusion as a stimulus for growth hormone release in man.

    PubMed

    Kellerová, E; Vigas, M

    1980-01-01

    In healthy male volunteers the effect of a short-term cerebral ischemia due to an acute orthostatic hypotension, on the release of growth hormone (HGH) was studied. Peroral administration of guanethidine 12.5 mg t.i.d. for 3 days plus 25 mg before the experiment was used to block peripheral vascular reflexes and thus to provoke orthostatic intolerance. An extreme increase of HGH serum levels (on average from 0.8 to 13.6 ng/ml; p < 0.001) was found in subjects who developed clinical signs of syncope after assuming upright posture. The possible mechanisms of this finding are discussed.

  14. Specific involvement of gonadal hormones in the functional maturation of growth hormone releasing hormone (GHRH) neurons.

    PubMed

    Gouty-Colomer, Laurie-Anne; Méry, Pierre-François; Storme, Emilie; Gavois, Elodie; Robinson, Iain C; Guérineau, Nathalie C; Mollard, Patrice; Desarménien, Michel G

    2010-12-01

    Growth hormone (GH) is the key hormone involved in the regulation of growth and metabolism, two functions that are highly modulated during infancy. GH secretion, controlled mainly by GH releasing hormone (GHRH), has a characteristic pattern during postnatal development that results in peaks of blood concentration at birth and puberty. A detailed knowledge of the electrophysiology of the GHRH neurons is necessary to understand the mechanisms regulating postnatal GH secretion. Here, we describe the unique postnatal development of the electrophysiological properties of GHRH neurons and their regulation by gonadal hormones. Using GHRH-eGFP mice, we demonstrate that already at birth, GHRH neurons receive numerous synaptic inputs and fire large and fast action potentials (APs), consistent with effective GH secretion. Concomitant with the GH secretion peak occurring at puberty, these neurons display modifications of synaptic input properties, decrease in AP duration, and increase in a transient voltage-dependant potassium current. Furthermore, the modulation of both the AP duration and voltage-dependent potassium current are specifically controlled by gonadal hormones because gonadectomy prevented the maturation of these active properties and hormonal treatment restored it. Thus, GHRH neurons undergo specific developmental modulations of their electrical properties over the first six postnatal weeks, in accordance with hormonal demand. Our results highlight the importance of the interaction between the somatotrope and gonadotrope axes during the establishment of adapted neuroendocrine functions.

  15. Effects of retinoic acid on growth hormone-releasing hormone receptor, growth hormone secretagogue receptor gene expression and growth hormone secretion in rat anterior pituitary cells.

    PubMed

    Maliza, Rita; Fujiwara, Ken; Tsukada, Takehiro; Azuma, Morio; Kikuchi, Motoshi; Yashiro, Takashi

    2016-06-30

    Retinoic acid (RA) is an important signaling molecule in embryonic development and adult tissue. The actions of RA are mediated by the nuclear receptors retinoic acid receptor (RAR) and retinoid X receptor (RXR), which regulate gene expression. RAR and RXR are widely expressed in the anterior pituitary gland. RA was reported to stimulate growth hormone (GH) gene expression in the anterior pituitary cells. However, current evidence is unclear on the role of RA in gene expression of growth hormone-releasing hormone receptor (Ghrh-r), growth hormone secretagogue receptor (Ghs-r) and somatostatin receptors (Sst-rs). Using isolated anterior pituitary cells of rats, we examined the effects of RA on gene expression of these receptors and GH release. Quantitative real-time PCR revealed that treatment with all-trans retinoic acid (ATRA; 10(-6) M) for 24 h increased gene expression levels of Ghrh-r and Ghs-r; however, expressions of Sst-r2 and Sst-r5 were unchanged. Combination treatment with the RAR-agonist Am80 and RXR-agonist PA024 mimicked the effects of ATRA on Ghrh-r and Ghs-r gene expressions. Exposure of isolated pituitary cells to ATRA had no effect on basal GH release. In contrast, ATRA increased growth hormone-releasing hormone (GHRH)- and ghrelin-stimulated GH release from cultured anterior pituitary cells. Our results suggest that expressions of Ghrh-r and Ghs-r are regulated by RA through the RAR-RXR receptor complex and that RA enhances the effects of GHRH and ghrelin on GH release from the anterior pituitary gland.

  16. Resistance to growth hormone releasing hormone and gonadotropins in Albright's hereditary osteodystrophy.

    PubMed

    Mantovani, Giovanna; Spada, Anna

    2006-05-01

    Heterozygous inactivating mutations in the Gs alpha gene cause Albright's hereditary osteo-dystrophy (AHO). Consistent with the observation that only maternally inherited mutations lead to resistance to hormone action (pseudohypoparathyroidism type Ia [PHP-Ia), recent studies have provided evidence for a predominant maternal origin of Gs alpha transcripts in endocrine organs, such as thyroid, gonad and pituitary. Accordingly, patients with PHP-Ia display variable degrees of resistance to parathyroid hormone (PTH), thyroid stimulating hormone (TSH), gonadotropins and growth hormone (GH) releasing hormone (GHRH). Although the incidence and the clinical and biochemical characteristics of PTH and TSH resistance have been widely investigated and described, the cause and significance of the reproductive dysfunction in AHO is still poorly understood. The clinical finding of alterations of GH secretion in these patients was described for the first time only 2 years ago. The present report briefly reviews the literature focusing on the actual knowledge about these last two subjects.

  17. Nitrogen balance and mineral excretion in growing male pigs injected with a human growth hormone-releasing factor analog.

    PubMed Central

    Dubreuil, P; Abribat, T; Brazeau, P; Lapierre, H

    1998-01-01

    A human growth hormone-releasing factor analog ([Desamino-Tyr1,D-Ala2,Ala15] hGRF(1-29) NH2) has been reported to reduce feed intake and increase growth and feed efficiency in a dose-dependent manner in growing pigs. The aim of this study was to determine the effect of this analog on nitrogen (N) balance and mineral excretion. Fifteen castrated male Yorkshire x Landrace pigs (45.9 +/- 1.4 kg) were randomly allotted to 2 groups: control (saline, n = 7) and GRF (6.66 micrograms/kg sc, TID, n = 8). The animals were injected for 20 consecutive days: feces and urine were collected during the last 10 d of injection. The animals had free access to water and food until satiety (approximately 15 min) at 07:00, 11:00, 15:00, 19:00, 23:00 and 07:00 h. The diet consisted of a hog fattening ration (18.0% crude protein). Blood samples were collected on the last day of the study by venipuncture. This analog increased (P < 0.05) insulin-like growth factor-1 and glucose serum concentrations and decreased (P < 0.05) serum urea nitrogen concentration and feed intake. The GRF-treated animals ingested less N, excreted less N in urine and feces to retain a similar amount of N than controls. The apparent coefficient of digestibility of the N has been slightly increased (P < 0.05) by GRF. Urinary excretion of P, K, and Cl decreased (P < 0.01) with GRF treatment. In conclusion, this GRF analog increased N digestibility and retention relative to N ingestion and reduced urinary N, P, K, and Cl excretion. PMID:9442933

  18. Effects of an Antagonistic Analog of Growth Hormone-Releasing Hormone on Endometriosis in a Mouse Model and In Vitro.

    PubMed

    Köster, Frank; Jin, Li; Shen, Yuanming; Schally, Andrew V; Cai, Ren-Zhi; Block, Norman L; Hornung, Daniela; Marschner, Gabriele; Rody, Achim; Engel, Jörg B; Finas, Dominique

    2017-01-01

    Endometriosis is a benign gynecologic disorder causing dysmenorrhea, pelvic pain, and subfertility. Receptors for the growth hormone-releasing hormone (GHRH) were found in endometriotic tissues. Antagonists of GHRH have been used to inhibit the growth of endometriotic endometrial stromal cells. In this study, the GHRH receptor splice variant (SV) 1 was detected in human endometrial tissue samples by Western blots and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The highest messenger RNA (mRNA) and protein levels of SV1 were found in eutopic endometrium from patients with endometriosis compared to ectopic endometriotic tissues and endometrium from normal patients. The highest expression for GHRH mRNA was found by qRT-PCR in ectopic endometriosis lesions. In an in vivo mouse model with human endometrial explants from patients with endometriosis, 10 μg MIA-602 per day resulted in significantly smaller human endometrial xenotransplants after 4 weeks compared to mice treated with vehicle. The endometrial tissues expressed SV1 before and after xenotransplantation. The proliferation of endometrial stromal cells as well as the endometriosis cell lines 12-Z and 49-Z was decreased by exposure to 1 μM MIA-602 after 72 hours. The protein levels of epithelial growth factor receptors in 12-Z and 49-Z cell lines were reduced 48 and 72 hours after the administration of 1 μM MIA-602. MIA-602 decreased the activation of the MAP-kinases ERK-1/2. Our study demonstrates the presence of SV1 receptor as a target for treatment with GHRH antagonist in endometriosis. Endometrial tissues respond to MIA-602 with inhibition of proliferation in vitro and in vivo. The use of MIA-602 could be an effective supplement to the treatment strategies in endometriosis.

  19. The expression of growth hormone-releasing hormone (GHRH) and splice variants of its receptor in human gastroenteropancreatic carcinomas

    PubMed Central

    Busto, Rebeca; Schally, Andrew V.; Varga, Jozsef L.; Garcia-Fernandez, M. Olga; Groot, Kate; Armatis, Patricia; Szepeshazi, Karoly

    2002-01-01

    Splice variants (SVs) of receptors for growth hormone-releasing hormone (GHRH) have been found in primary human prostate cancers and diverse human cancer cell lines. GHRH antagonists inhibit growth of various experimental human cancers, including pancreatic and colorectal, xenografted into nude mice or cultured in vitro, and their antiproliferative action could be mediated in part through SVs of GHRH receptors. In this study we examined the expression of mRNA for GHRH and for SVs of its receptors in tumors of human pancreatic, colorectal, and gastric cancer cell lines grown in nude mice. mRNA for both GHRH and SV1 isoform of GHRH receptors was expressed in tumors of pancreatic (SW1990, PANC-1, MIA PaCa-2, Capan-1, Capan-2, and CFPAC1), colonic (COLO 320DM and HT-29), and gastric (NCI-N87, HS746T, and AGS) cancer cell lines; mRNA for SV2 was also present in Capan-1, Capan-2, CFPAC1, HT-29, and NCI-N87 tumors. In proliferation studies in vitro, the growth of pancreatic, colonic, and gastric cancer cells was stimulated by GHRH(1–29)NH2 and inhibited by GHRH antagonist JV-1–38. The stimulation of some gastroenteropancreatic cancer cells by GHRH was followed by an increase in cAMP production, and GHRH antagonist JV-1–38 competitively inhibited this effect. Our study indicates the presence of an autocrine/paracrine stimulatory loop based on GHRH and SV1 of GHRH receptors in human pancreatic, colorectal, and gastric cancers. The finding of SV1 receptor in human cancers provides an approach to an antitumor therapy based on the blockade of this receptor by specific GHRH antagonists. PMID:12186980

  20. 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.

  1. 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.

  2. Thyroid hormone and estrogen regulate exercise-induced growth hormone release.

    PubMed

    Ignacio, Daniele Leão; da S Silvestre, Diego H; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Louzada, Ruy Andrade; Carvalho, Denise P; Werneck-de-Castro, João Pedro

    2015-01-01

    Growth hormone (GH) regulates whole body metabolism, and physical exercise is the most potent stimulus to induce its secretion in humans. The mechanisms underlying GH secretion after exercise remain to be defined. The aim of this study was to elucidate the role of estrogen and pituitary type 1 deiodinase (D1) activation on exercise-induced GH secretion. Ten days after bilateral ovariectomy, animals were submitted to 20 min of treadmill exercise at 75% of maximum aerobic capacity and tissues were harvested immediately or 30 min after exercise. Non-exercised animals were used as controls. A significant increase in D1 activity occurred immediately after exercise (~60%) in sham-operated animals and GH was higher (~6-fold) 30 min after exercise. Estrogen deficient rats exhibited basal levels of GH and D1 activity comparable to those found in control rats. However, after exercise both D1 activity and serum GH levels were blunted compared to sedentary rats. To understand the potential cause-effect of D1 activation in exercise-induced GH release, we pharmacologically blocked D1 activity by propylthiouracil (PTU) injection into intact rats and submitted them to the acute exercise session. D1 inhibition blocked exercise-induced GH secretion, although basal levels were unaltered. In conclusion, estrogen deficiency impairs the induction of thyroid hormone activating enzyme D1 in the pituitary, and GH release by acute exercise. Also, acute D1 activation is essential for exercise-induced GH response.

  3. Growth hormone releasing hexapeptide-6 (GHRP-6) test in the diagnosis of GH-deficiency.

    PubMed

    Pombo, M; Leal-Cerro, A; Barreiro, J; Peñalva, A; Peino, R; Mallo, F; Dieguez, C; Casanueva, F F

    1996-06-01

    Pituitary GH reserve can be assessed by substances that act directly at the somatotroph, such as GHRH, or by a variety of metabolic and neuropharmacological tests acting at the hypothalamic level, such as hypoglycemia, clonidine or L-Dopa. In order to evaluate GHRP-6 as a test of pituitary GH reserve, we studied GH responses of i.v. administered GHRP-6 in a group of short-statured children, as well as in a group of adults diagnosed with growth hormone deficiency (GHD) by conventional GH testing. Although we found that the GH response to GHRP-6 was lower in patients with GHD than in normal children, on an individual basis a considerable degree of overlap was observed between the two groups. In contrast, we found an almost complete blockade of GH response to either GHRP-6 or GHRH plus GHRP-6 in patients with pituitary stalk transection, suggesting that this could be a cost-effective test for the diagnosis of this condition. A similar finding was also obtained in GH response to the combined administration of GHRH plus GHRP-6 in patients with GHD of adult onset; this test may well prove valuable in the diagnosis of this clinical entity.

  4. Thyroid Hormone and Estrogen Regulate Exercise-Induced Growth Hormone Release

    PubMed Central

    Ignacio, Daniele Leão; da S. Silvestre, Diego H.; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Louzada, Ruy Andrade

    2015-01-01

    Growth hormone (GH) regulates whole body metabolism, and physical exercise is the most potent stimulus to induce its secretion in humans. The mechanisms underlying GH secretion after exercise remain to be defined. The aim of this study was to elucidate the role of estrogen and pituitary type 1 deiodinase (D1) activation on exercise-induced GH secretion. Ten days after bilateral ovariectomy, animals were submitted to 20 min of treadmill exercise at 75% of maximum aerobic capacity and tissues were harvested immediately or 30 min after exercise. Non-exercised animals were used as controls. A significant increase in D1 activity occurred immediately after exercise (~60%) in sham-operated animals and GH was higher (~6-fold) 30 min after exercise. Estrogen deficient rats exhibited basal levels of GH and D1 activity comparable to those found in control rats. However, after exercise both D1 activity and serum GH levels were blunted compared to sedentary rats. To understand the potential cause-effect of D1 activation in exercise-induced GH release, we pharmacologically blocked D1 activity by propylthiouracil (PTU) injection into intact rats and submitted them to the acute exercise session. D1 inhibition blocked exercise-induced GH secretion, although basal levels were unaltered. In conclusion, estrogen deficiency impairs the induction of thyroid hormone activating enzyme D1 in the pituitary, and GH release by acute exercise. Also, acute D1 activation is essential for exercise-induced GH response. PMID:25874614

  5. Alpha-adrenergic control of growth hormone release during surgical stress in man.

    PubMed

    Vigas, M; Malatinský, J; Németh, S; Jurcovicová, J

    1977-04-01

    The mechanisms involved in the initial release of growth hormone (GH) during cholecystectomy have been studied after the administration of phentolamine in saline and in isotonic glucose, and after the administration of 10% glucose. Infusion of these substances was started 10 min before and terminated 30 min after skin incision. The serum GH levels 30 min after skin incision in a nontreated control group were raised to 14.4 +/- 1.0 ng/ml. The alpha-adrenergic blockade by phentolamine (20 mg during 40 min) regardless of whether administered in saline or in isotonic glucose inhibited GH response to surgery (4.3 +/- 2.1 ng/ml, or 2.2 +/- 0.4 ng/ml). The administration of 10% glucose (40 g during 40 min) led to a diminished response in some, but not in all the patients (6.2 +/- 1.2 ng/ml). It is concluded that the alpha-adrenergic mechanism participates in GH response to surgery.

  6. Gender-related differences in growth hormone-releasing pituitary adenomas. A clinicopathological study.

    PubMed

    Schaller, Bernhard

    2002-01-01

    Pituitary adenomas are the third most common primary intracranial neoplasm, after astrocytomas and meningiomas, and about 30% of them secrete growth hormone (GH). Other subtypes of pituitary tumors are characterized by well-known gender-related differences, not only in clinical presentation and other biological characteristics but also in surgical outcome. For GH-releasing pituitary adenomas, however, detailed data on gender differences of postsurgical treatment are not available. The patient charts of a series of 18 patients with acromegaly who met strict immunohistochemical and electron microscopic criteria and who underwent surgical resection of their tumors between January 1990 and June 1999 were retrospectively reviewed. There were eight women and ten men; the male-to-female-ratio was 1.3:1. The men and women were equal in age at surgery. Men demonstrated higher IGF-1 and smaller GH levels pre- and postoperatively, whereas the reduction in IGF-1 was more pronounced compared to women (58% vs. 27%). The overall outcome was better in women than in men. Mixed GH- and prolactin-secreting adenomas showed a worse outcome among all other histological subtypes. Mitose- and MIB-1 labeling index was increased in men compared to women. The clinical course and tumor biology of GH-releasing pituitary adenomas appear to differ in women and men. Men demonstrated a shorter preoperative duration of symptoms, larger and more invasive tumors, and a worse clinical outcome. These findings suggest that therapy for GH-releasing adenomas should be more aggressive in men than in women. The gender-related differences in GH-releasing pituitary adenomas appear to have a basis in different biologic behavior, which warrants further investigation.

  7. Sulfated gastrin stimulates ghrelin and growth hormone release but inhibits insulin secretion in cattle.

    PubMed

    Zhao, Hongqiong; Yannaing, Swe; Thanthan, Sint; Kuwayama, Hideto

    2011-11-01

    This study was designed to determine the effects of gastrin on the circulating levels of ghrelin, growth hormone (GH), insulin, glucagon and glucose in ruminants. Two experiments were done in eight Holstein steers. Animals were randomly assigned to receive intravenous bolus injections: (1) 0.1% bovine serum albumin in saline as vehicle, 0.8, 4.0 and 20.0 μg/kg body weight (BW) of bovine sulfated gastrin-34; (2) vehicle, 0.53 μg/kg BW of bovine sulfated gastrin-17 alone or combined with 20.0 μg/kg BW of [D-Lys(3)]-GHRP-6, the selective antagonist of GHS-R1a. Blood samples were collected from -10 to 150 min relative to injection time. Concentrations of acyl and total ghrelin in response to gastrin-34 injection were significantly increased in a dose-dependent manner. Concentrations of GH were also markedly elevated by gastrin-34 injection; however, the effect of 20.0 μg/kg was weaker than that of 4.0 μg/kg. The three doses of gastrin-34 equally decreased insulin levels within 15 min and maintained the level until the time of last sampling. Gastrin-34 had no effect (P > 0.05) on the levels of glucagon and glucose. Levels of acyl ghrelin increased after administration of gastrin-17 alone or combined with [D-Lys(3)]-GHRP-6; however, [D-Lys(3)]-GHRP-6 did not block the elevation of GH by gastrin-17. The present results indicate that sulfated gastrin stimulates both ghrelin and GH release, but the GHS-R1a may not contribute to the release of GH by gastrin. Moreover, sulfated gastrin seems to indirectly maintain the homeostasis of blood glucose through the down-regulation of insulin in ruminants.

  8. Long-acting delivery systems for peptides: inhibition of rat prostate tumors by controlled release of [D-Trp6]luteinizing hormone-releasing hormone from injectable microcapsules.

    PubMed Central

    Redding, T W; Schally, A V; Tice, T R; Meyers, W E

    1984-01-01

    Intramuscular injection of [6-D-tryptophan]-luteinizing hormone-releasing hormone [( D-Trp6]LH-RH) in microcapsules of poly(DL-lactide-co-glycolide), designed to release a controlled dose of the peptide over a 30-day period, decreased the weights of androgen-dependent Dunning prostate tumors in rats and suppressed serum testosterone levels more effectively than daily subcutaneous administration of equivalent or double doses of unencapsulated [D-Trp6]LH-RH. The microcapsules or daily injections of [D-Trp6]LH-RH also significantly decreased tumor volumes. Microcapsules of [D-Trp6]LH-RH or related analogs that can be injected once a month should make the treatment of patients with prostate carcinoma and other neoplasms or disorders more convenient and efficacious. Images PMID:6237365

  9. Development of a recombinant bovine leukemia virus vector for delivery of a synthetic bovine growth hormone-releasing factor gene into bovine cells.

    PubMed

    Mehigh, C S; Elias, V D; Mehigh, R J; Helferich, W G; Tucker, H A

    1993-03-01

    Continuous intravenous infusion of bovine growth hormone-releasing factor (bGRF) increases milk synthesis in dairy cattle by as much as 46%. We have begun to develop a system for delivery and expression of a synthetic bGRF gene in cultured bovine cells using the provirus of the bovine leukemia virus (BLV). The gene encoding synthetic bGRF, constructed from eight overlapping oligonucleotides, was fused to the whey acidic protein promoter (WAP) or the mouse mammary tumor virus promoter (MMTV). These plasmids, termed pWAP.GRF and pMMTV.GRF, were able to induce transcription of bGRF upon transfection into Madin-Darby bovine kidney (MDBK) cells and induction with a lactogenic hormonal milieu (prolactin, hydrocortisone, triiodothyronine, insulin) or dexamethasone. When these constructs were cloned into a BLV vector in place of its oncogenic region, and transfected into MDBK cells, bGRF was expressed. Virus particles were prepared from these cultures and used to deliver the bGRF gene by viral infection into fresh MDBK cells. Northern blot analysis of MDBK total RNA revealed a fivefold higher level of expression of bGRF mRNA in transfected cultures than in virally infected cells, and no expression was detected in control cultures. The bGRF peptide was detected in both cell extracts and media samples from transfected cultures but was not detected in cell extracts or media samples from virally infected cells. This provirus construct may prove useful as a delivery system for peptides into cattle.

  10. Agonists of growth hormone-releasing hormone stimulate self-renewal of cardiac stem cells and promote their survival.

    PubMed

    Florea, Victoria; Majid, Sonia S; Kanashiro-Takeuchi, Rosemeire M; Cai, Ren-Zhi; Block, Norman L; Schally, Andrew V; Hare, Joshua M; Rodrigues, Claudia O

    2014-12-02

    The beneficial effects of agonists of growth hormone-releasing hormone receptor (GHRH-R) in heart failure models are associated with an increase in the number of ckit(+) cardiac stem cells (CSCs). The goal of the present study was to determine the presence of GHRH-R in CSCs, the effect of GHRH-R agonists on their proliferation and survival, and the mechanisms involved. We investigated the expression of GHRH-R in CSCs of different species and the effect of GHRH-R agonists on their cell proliferation and survival. GHRH-R is expressed in ckit(+) CSCs isolated from mouse, rat, and pig. Treatment of porcine CSCs with the GHRH-R agonist JI-38 significantly increased the rate of cell division. Similar results were observed with other GHRH-R agonists, MR-356 and MR-409. JI-38 exerted a protective effect on survival of porcine CSCs under conditions of oxidative stress induced by exposure to hydrogen peroxide. Treatment with JI-38 before exposure to peroxide significantly reduced cell death. A similar effect was observed with MR-356. Addition of GHRH-R agonists to porcine CSCs induced activation of ERK and AKT pathways as determined by increased expression of phospho-ERK and phospho-AKT. Inhibitors of ERK and AKT pathways completely reversed the effect of GHRH-R agonists on CSC proliferation. Our findings extend the observations of the expression of GHRH-R by CSCs and demonstrate that GHRH-R agonists have a direct effect on proliferation and survival of CSCs. These results support the therapeutic use of GHRH-R agonists for stimulating endogenous mechanisms for myocardial repair or for preconditioning of stem cells before transplantation.

  11. Direct nose-to-brain transfer of a growth hormone releasing neuropeptide, hexarelin after intranasal administration to rabbits.

    PubMed

    Yu, Hui; Kim, Kwonho

    2009-08-13

    The purpose of this study was to investigate the olfactory transfer of a growth hormone releasing neuropeptide, hexarelin to the brain tissues by comparing brain uptake levels after intranasal administration with those after intravenous administration. The hexarelin nasal formulation was prepared using an aqueous cosolvent vehicle consisting of ethanol, propylene glycol, and n-tridecyl-beta-D-maltoside as a permeation enhancer. Hexarelin was administered intravenously or intranasally to male rabbits at a dose of 1 mg/kg. Drug concentrations in the plasma, cerebrospinal fluid and six different regions of the brain, i.e., olfactory bulb (OB), olfactory tract (OT), anterior (CB1), middle (CB2), posterior (CB3) cerebrum, and cerebellum (CL) were analyzed by LC/MS method after solid phase extraction. The brain and cerebrospinal fluid levels achieved following intranasal administration were approximately 1.6 times greater than those attained after intravenous administration despite the intranasal plasma levels being significantly lower than the intravenous plasma levels. Intranasal administration resulted in significantly different spatial distribution patterns in various regions of brain with the rank order of C(OB)>C(OT)>C(CB1, CB2, CB3)>C(CL) at 10, 20, and 40 min post-dosing, whereas intravenous administration yielded nearly similar distribution patterns in the brain. The intranasal administration into one nostril (left or right) exhibited markedly greater hexarelin concentrations in olfactory bulb and olfactory tract on the treated-side of brain tissues than those on the non-treated-side of the brain hemisphere. It was demonstrated that the hydrophilic neuropeptide hexarelin was transferred via olfactory pathway to the brain hemispheres and the drug transfer via this route significantly contributed to high brain concentrations after nasal administration to rabbits.

  12. Discordant effects of endogenous and exogenous somatostatin on growth hormone-releasing hormone secretion from perifused mouse hypothalami.

    PubMed

    Pecori Giraldi, F; Frohman, L A

    1995-05-01

    The role of somatostatin (SRIF) on growth hormone-releasing hormone (GRH) secretion has been controversial because of discordant findings that may be model dependent. We have examined possible explanations for these findings by altering endogenous and exogenous SRIF tone in a mouse hypothalamic perifusion system. Four mediobasal hypothalamic fragments were perifused in a single chamber for 6 h. After a 2-hour equilibration period, test substances were introduced and maintained throughout the perifusion. After an additional 2 h, fragments were submaximally stimulated with 30 mM K+. Depletion of tissue SRIF by 10(-3) M cysteamine increased K(+)-stimulated GRH release 2-fold without altering basal GRH secretion. Removal of endogenous SRIF tone by anti-SRIF serum also augmented the GRH response to K+. Perifusion of SRIF at concentrations ranging from 10(-12) to 10(-8) M significantly increased the GRH response to K+ in a dose-dependent manner. A significant increase was also observed during the perifusion of 10(-9) M octreotide. Simultaneous perifusion with anti-SRIF serum and 10(-9) M octreotide (to which the antibody does not bind) resulted in a response of GRH to K+ that was similar to that observed with anti-SRIF serum alone. Combined perifusion with cysteamine and 10(-9) M SRIF also resulted in a GRH response to K+ that did not differ from the response observed during cysteamine alone. The enhancement of GRH secretion by reduction of endogenous SRIF tone or tissue content implies an inhibitory role of endogenous SRIF on GRH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Basic fibroblast growth factor priming increases the responsiveness of immortalized hypothalamic luteinizing hormone releasing hormone neurones to neurotrophic factors.

    PubMed

    Gallo, F; Morale, M C; Tirolo, C; Testa, N; Farinella, Z; Avola, R; Beaudet, A; Marchetti, B

    2000-10-01

    The participation of growth factors (GFs) in the regulation of luteinizing hormone releasing hormone (LHRH) neuronal function has recently been proposed, but little is known about the role played by GFs during early LHRH neurone differentiation. In the present study, we have used combined biochemical and morphological approaches to study the ability of a number of GFs normally expressed during brain development, including basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) to induce survival, differentiation, proliferation, and phenotypic expression of immortalized (GT1-1) LHRH neurones in vitro, at early (3-days in vitro, 3-DIV) and late (8-DIV) stages of neuronal differentiation. Comparison of GF-treated vs untreated neurones grown in serum-deprived (SD) medium demonstrated bFGF to be the most potent, and insulin the least active in promoting neuronal differentiation. Thus, at both 3-DIV and 8-DIV, but especially at 8-DIV, bFGF induced the greatest increase in the total length and number of LHRH processes/cell and in growth cone surface area. bFGF was also the most active at 3-DIV, and IGF-I at 8-DIV, in counteracting SD-induced cell death, whereas EGF was the most potent in increasing [3H]thymidine incorporation. All GFs studied decreased the spontaneous release of LHRH from GT1-1 cells when applied at 3-DIV or 8-DIV, except for insulin which was inactive at both time-points and bFGF which was inactive at 8-DIV. Pre-treatment of GT1-1 cells with a suboptimal ('priming') dose of bFGF for 12 h followed by application of the different GFs induced a sharp potentiation of the neurotrophic and proliferative effects of the latter and particularly of those of IGF-I. Moreover, bFGF priming counteracted EGF-induced decrease in LHRH release and significantly stimulated LHRH secretion following IGF-I or insulin application, suggesting that bFGF may sensitize LHRH neurones to differentiating effects of

  14. Effects of the growth hormone-releasing hormone (GH-RH) antagonist on brain functions in mice.

    PubMed

    Telegdy, Gyula; Tanaka, Masaru; Schally, Andrew V

    2011-10-10

    The growth hormone-releasing hormone (GH-RH) antagonist MZ-4-71 has been shown to suppress secretion of GH and insulin-like growth factor-1 (IGF-1) secretion. These findings suggested that GH-RH antagonists could be used for the therapy of disorders characterized by excessive GH secretion. A number of GH-RH antagonists has been synthesized, and shown to suppress the growth of various tumors. However, little is known about the possible action of GR-RH antagonists on brain functions. In the present work, the influence of MZ-4-71 on different aspects of brain function was studied in mice, following its administration into the lateral brain ventricle. The effects tested included the action of MZ-4-71 on passive avoidance learning and on the impairment of the consolidation of a passive avoidance reflex caused by beta-amyloid 25-35, antidepressive action in a forced swimming test, and anxiolytic action on plus-maze and open-field behavior. MZ-4-71 facilitated the consolidation of passive avoidance learning. Beta-amyloid 25-35 administered immediately after the learning trial impaired the consolidation of passive avoidance learning. MZ-4-71 fully blocked this impairment when given simultaneously with or 30min following beta-amyloid 25-35 administration icv. In the forced swimming tests, MZ-47-1 demonstrated antidepressive-like action and in the plus-maze, depending on the dose used it elicited mild anxiolytic action, however, in open-field behavior tests, it displayed no action on locomotion, rearing or grooming. The results demonstrate that MZ-4-71 affects the brain functions: by improving memory consolidation in passive avoidance learning and correcting the impairment of the memory consolidation caused by beta-amyloid 25-35. MZ-4-71 also elicits anxiolytic and antidepressive effects, but it does not influence the open-field activity. Further experimental work with MZ-4-71 is necessary, to determine the possible mechanism of action. The results imply a possible merit of

  15. Use of osmotic pumps for subcutaneous infusion of growth hormone-releasing factors in steers and wethers.

    PubMed

    Wheaton, J E; al-Raheem, S N; Godfredson, J A; Dorn, J M; Wong, E A; Vale, W; Rivier, J; Mowles, T F; Heimer, E P; Felix, A M

    1988-11-01

    Osmotic pumps were evaluated for 7-d delivery of growth hormone-releasing factor (GRF). In Exp. 1, 12 steers weighing 253 kg received hGRF(1-29)NH2 in H2O at rates of 0, 3, 30 and 300 pmol.h-1.kg-1. Pumps were implanted s.c. on d 0 and removed at 1200 on d 7. Blood samples were drawn at 20-min intervals from 0800 to 1200 on d -1, 1, 3, 5, 7 and 9. Growth hormone levels were not altered by GRF treatment (P greater than .05). Solubility and volume limitations render hGRF(1-29)NH2 delivery via osmotic pumps problematical. Flow rate and duration of release of dimethyl sulfoxide (DMSO):H2) (1:1) from osmotic pumps incubated in vivo and in vitro were found to be consistent with manufacturer's specifications. Two hGRF(1-29) analogues, Ro23-7863 and 4SG-29, were dissolved in DMSO:H2O. In Exp. 2, six 222-kg steers had pumps implanted and blood samples were taken as in Exp. 1. Three steers received each analogue at a rate of 300 pmol.h-1.kg-1. Analogues had similar GH-releasing ability and GH levels differed (P less than 0.001) among days, being approximately fourfold higher on d 3, 5 and 7 than on d -1, 1 and 9. Residual analogue solutions retained full bioactivity after 7-d implantation, and in vitro biopotencies of Ro23-7863 and 4SG-29 were similar (Exp. 3). In Exp. 4, 15 wethers (means = 31.3 kg) received osmotic pumps delivering 0, 3, 15, 75 and 300 pmol.h-1.kg-1 Ro23-7863 in DMSO:H2O for 7 d. Lambs were bled at 0800 and 1400 from d -1 to 8. The latter two doses increased (P less than .01) mean GH levels 2.7- and 4.3-fold over those in control animals during the treatment period. Results demonstrate that increased GH secretion can be elicited in steers and wethers for 1 wk by continuous s.c. infusion of GRF analogues utilizing osmotic pumps.

  16. Experiment K-7-22: Growth Hormone Regulation Synthesis and Secretion in Microgravity. Part 2; Hypothalamic Growth Hormone-Releasing Factor, Somatostatin Immunoreactivity, and Messenger RNA Levels in Microgravity

    NASA Technical Reports Server (NTRS)

    Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

    1994-01-01

    Immunohistochemical analyses of hypothalamic hormones carried out on tissue from rats flown on an earlier flight (Cosmos 1887) suggested preferential effects on hypophysiotropic principles involved in the regulation of growth hormone secretion and synthesis. We found that staining in the median eminence for peptides that provide both stimulatory (growth hormone-releasing factor, or GRF) and inhibitory (somatostatin, SS) influences on growth hormone secretion were depressed in flight animals relative to synchronous controls, while staining for other neuroendocrine peptides, cortocotropin-releasing factor and arginine vasopressin, were similar in these two groups. While this suggests some selective impact of weightlessness on the two principal central nervous system regulators of growth hormone dynamics, the fact that both GRF- and SS-immunoreactivity (IR) appeared affected in the same direction is somewhat problematic, and makes tentative any intimation that effects on CNS control mechanisms may be etiologically significant contributors to the sequelae of reduced growth hormone secretion seen in prolonged space flight. To provide an additional, and more penetrating, analysis we attempted in hypothalamic material harvested from animals flown on Cosmos 2044 to complement immunohistochemical analyses of GRF and SS staining with quantitative, in situ assessments of messenger RNAs encoding the precursors for both these hormones.

  17. Experiment K-7-22: Growth Hormone Regulation Synthesis and Secretion in Microgravity. Part 2; Hypothalamic Growth Hormone-Releasing Factor, Somatostatin Immunoreactivity, and Messenger RNA Levels in Microgravity

    NASA Technical Reports Server (NTRS)

    Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

    1994-01-01

    Immunohistochemical analyses of hypothalamic hormones carried out on tissue from rats flown on an earlier flight (Cosmos 1887) suggested preferential effects on hypophysiotropic principles involved in the regulation of growth hormone secretion and synthesis. We found that staining in the median eminence for peptides that provide both stimulatory (growth hormone-releasing factor, or GRF) and inhibitory (somatostatin, SS) influences on growth hormone secretion were depressed in flight animals relative to synchronous controls, while staining for other neuroendocrine peptides, cortocotropin-releasing factor and arginine vasopressin, were similar in these two groups. While this suggests some selective impact of weightlessness on the two principal central nervous system regulators of growth hormone dynamics, the fact that both GRF- and SS-immunoreactivity (IR) appeared affected in the same direction is somewhat problematic, and makes tentative any intimation that effects on CNS control mechanisms may be etiologically significant contributors to the sequelae of reduced growth hormone secretion seen in prolonged space flight. To provide an additional, and more penetrating, analysis we attempted in hypothalamic material harvested from animals flown on Cosmos 2044 to complement immunohistochemical analyses of GRF and SS staining with quantitative, in situ assessments of messenger RNAs encoding the precursors for both these hormones.

  18. 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…

  19. 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…

  20. Growth hormone releasing factor (GRF) increases free arachidonate levels in the pituitary: a role for lipoxygenase products

    SciTech Connect

    Canonico, P.L.; Speciale, C.; Sortino, M.A.; Cronin, M.J.; MacLeod, R.M.; Scapagnini, U.

    1986-01-20

    GRF, a specific stimulator of GH release, increased in a concentration- and time-dependent manner pituitary (/sup 3/H)-arachidonate levels in vitro. This effect was antagonized by 100 nM somatostatin. Exogenous arachidonate also stimulated GH release in vitro. Quinacrine, a phospholipase A2 inhibitor, reduced both basal and GRF-stimulated free arachidonate levels as well as GH release. The cyclooxygenase inhibitor indomethacin was ineffective, while BW755c, which also inhibits the lipoxygenase pathway, produced a further increase in the levels of the fatty acid stimulated by GRF and potently reduced GH release. These results provide additional evidence for the involvement of arachidonate metabolism in the hormone-releasing effect of GRF at the somatotroph. 14 references, 1 figure, 2 tables.

  1. Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

    SciTech Connect

    Romshe, C.A.; Zipf, W.B.; Miser, A.; Miser, J.; Sotos, J.F.; Newton, W.A.

    1984-02-01

    We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significant differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response.

  2. Role of growth hormone-releasing hormone in sleep and growth impairments induced by upper airway obstruction in rats.

    PubMed

    Tarasiuk, A; Berdugo-Boura, N; Troib, A; Segev, Y

    2011-10-01

    Upper airway obstruction (UAO) can lead to abnormal growth hormone (GH) homeostasis and growth retardation but the mechanisms are unclear. We explored the effect of UAO on hypothalamic GH-releasing hormone (GHRH), which has a role in both sleep and GH regulation. The tracheae of 22-day-old rats were narrowed; UAO and sham-operated animals were sacrificed 16 days post-surgery. To stimulate slow-wave sleep (SWS) and GH secretion, rats were treated with ritanserin (5-HT(2) receptor antagonist). Sleep was measured with a telemetric system. Hypothalamic GHRH, hypothalamic GHRH receptor (GHRHR) and GH receptor, and orexin were analysed using ELISA, real-time PCR and Western blot. UAO decreased hypothalamic GHRH, GHRHR and GH receptor levels, while orexin mRNA increased (p<0.01). In UAO rats, the duration of wakefulness was elevated and the duration of SWS, paradoxical sleep and slow-wave activity was reduced (p<0.001). Ritanserin alleviated these effects, i.e. normalised hypothalamic GHRH content, decreased wake duration, increased duration and depth of SWS, and attenuated growth impairment (p<0.001). Here, we present evidence that growth retardation in UAO is associated with a reduction in hypothalamic GHRH content. Our findings show that abnormalities in the GHRH/GH axis underlie both growth retardation and SWS-disorder UAO.

  3. The influence of bovine growth hormone and growth hormone releasing factor on acetyl-CoA carboxylase and fatty acid synthase in primiparous Holstein cows.

    PubMed

    Beswick, N S; Kennelly, J J

    1998-08-01

    Primiparous Holstein cows received recombinant bovine growth hormone (bGH), bovine growth hormone-releasing factor (bGRF), or no treatment from 118 to 181 +/- 1 d. Milk yield was significantly increased with no change in milk fat percentage or composition. The mRNA and protein abundance of the key lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) were measured in the mammary gland and adipose tissue. We hypothesized that bGH and bGRF treatment would increase the mRNA and protein abundance of ACC and FAS in the mammary gland, with an associated decrease in adipose tissue. Analysis of ACC mRNA and protein abundance in the mammary gland revealed that there was no significant influence of either bGH or bGRF treatment. Analysis of FAS mRNA in mammary gland revealed that both bGH and bGRF significantly increased the abundance. However, quantitation of FAS protein in the mammary gland revealed that neither treatment resulted in increased abundance. In adipose tissue, the mRNA and protein abundance of both ACC and FAS were significantly reduced. The increased substrate required for increased milk fatty acid yield may be provided through redirection of nutrients to the mammary gland away from adipose tissue and through overall increased metabolism of the mammary gland.

  4. Testosterone inhibition of growth hormone release stimulated by a growth hormone secretagogue: studies in the rat and dog.

    PubMed

    Rigamonti, Antonello E; Cella, Silvano G; Giordani, Claudio; Bonomo, Sara M; Giunta, Marialuisa; Sartorio, Alessandro; Muller, Eugenio

    2006-01-01

    Anabolic steroids are frequently taken by athletes and bodybuilders together with recombinant human GH (rhGH), though there is some scientific evidence that the use of anabolic steroids reverses the rhGH-induced effects. Recently, we have shown that treatment with rhGH (0.2 IU/kg s.c., daily x 12 days) in the dog markedly reduced the canine GH (cGH) responses stimulated by EP51216, a GH secretagogue (GHS), evaluated after 3 and 5 daily rhGH injections, and that the inhibition was still present a few days after rhGH discontinuation. The aim of the present study was to evaluate in the dog the GH response to EP51216 (125 mug/kg i.v.) in a condition of enhanced androgenic function (i.e. acute injection or 15-day treatment with testosterone at the dose of 2 mg/kg i.m. on alternate days), and in the hypophysectomized rat the hypothalamic and hippocampal expression of ghrelin, the receptor of GHSs (GHS-R), GH-releasing hormone (GHRH) and somatostatin (SS) after specific hormonal replacement therapies (testosterone, 1 mg/kg/day s.c.; hydrocortisone, 500 mug/kg/day s.c.; rhGH, 400 mug/kg/day s.c.; 0.9% saline 0.1 ml/kg/day s.c.; x11 days). In the dog experiments, under baseline conditions, a single injection of EP51216 elicited an abrupt rise of plasma cGH. Twenty-four hours from the acute bolus injection of testosterone, C(max) and AUC(0-90) of the GHS-stimulated cGH response were significantly lower than baseline cGH response; 5 days later, there was still a significant decrease of either parameter versus the original values. Short-term treatment with testosterone markedly reduced the GHS-stimulated cGH responses evaluated during (5th bolus) and at the end (8th bolus) of testosterone treatment. Four and 8 days after testosterone withdrawal, the EP51216-stimulated cGH response was still significantly reduced when compared with that under baseline conditions. Plasma concentrations of insulin-like growth factor 1 (IGF-1) were stable until the 5th bolus of testosterone and

  5. Contribution of human growth hormone-releasing hormone receptor (GHRHR) gene sequence variation to isolated severe growth hormone deficiency (ISGHD) and normal adult height.

    PubMed

    Camats, Núria; Fernández-Cancio, Mónica; Carrascosa, Antonio; Andaluz, Pilar; Albisu, M Ángeles; Clemente, María; Gussinyé, Miquel; Yeste, Diego; Audí, Laura

    2012-10-01

    Molecular causes of isolated severe growth hormone deficiency (ISGHD) in several genes have been established. The aim of this study was to analyse the contribution of growth hormone-releasing hormone receptor (GHRHR) gene sequence variation to GH deficiency in a series of prepubertal ISGHD patients and to normal adult height. A systematic GHRHR gene sequence analysis was performed in 69 ISGHD patients and 60 normal adult height controls (NAHC). Four GHRHR single-nucleotide polymorphisms (SNPs) were genotyped in 248 additional NAHC. An analysis was performed on individual SNPs and combined genotype associations with diagnosis in ISGHD patients and with height-SDS in NAHC. Twenty-one SNPs were found. P3, P13, P15 and P20 had not been previously described. Patients and controls shared 12 SNPs (P1, P2, P4-P11, P16 and P21). Significantly different frequencies of the heterozygous genotype and alternate allele were detected in P9 (exon 4, rs4988498) and P12 (intron 6, rs35609199); P9 heterozygous genotype frequencies were similar in patients and the shortest control group (heights between -2 and -1 SDS) and significantly different in controls (heights between -1 and +2 SDS). GHRHR P9 together with 4 GH1 SNP genotypes contributed to 6·2% of height-SDS variation in the entire 308 NAHC. This study established the GHRHR gene sequence variation map in ISGHD patients and NAHC. No evidence of GHRHR mutation contribution to ISGHD was found in this population, although P9 and P12 SNP frequencies were significantly different between ISGHD and NAHC. Thus, the gene sequence may contribute to normal adult height, as demonstrated in NAHC. © 2012 Blackwell Publishing Ltd.

  6. Does growth hormone releasing factor desensitize the somatotroph? Interpretation of responses of growth hormone during and after 10-hour infusion of GRF 1-29 amide in man.

    PubMed

    Davis, J R; Sheppard, M C; Shakespear, R A; Lynch, S S; Clayton, R N

    1986-02-01

    It is unclear whether growth hormone releasing factor (GRF) administration in vivo may desensitize the somatotroph. To investigate this possibility we have examined the effects of 10-h infusion of the equipotent 1-29 amide analogue of hpGRF on serum GH levels and on the subsequent GH response to a bolus dose of GRF (1-29). Four normal adult males received an intravenous infusion of 1-29 GRF (1 microgram/kg/h) from 0800 to 1800 h, with blood samples taken at 10 min intervals. A 100 micrograms intravenous bolus dose of GRF was given at 1800 h, and sampling continued for a further 90 min. GH levels were near or below the limit of detection (0.5 mU/l) throughout the control 10 h period. During GRF infusion there was increased GH release with pulses of irregular frequency and amplitude (up to 80 mU/l) continuing throughout the entire infusion period. There was no apparent reduction in total GH released towards the latter part of the infusion. On the control day, 100 micrograms GRF bolus increased mean (+/- SEM) GH from 0.82 +/- 0.21 mU/l to a peak of 59.0 +/- 44.8 mU/l (P less than 0.002). Following 10-GRF infusion, responses to bolus injection of GRF were reduced, but variable. In two subjects a small rise in GH levels occurred (basal 6.4 and 7.2 rising to peak values of 11.2 and 23.0 mU/l respectively). In the other two subjects, GH levels fell but in these the GRF bolus had coincided with a GH peak. The loss of GRF responsiveness after GRF infusion may be due to 'desensitization'.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Elevation of growth hormone-releasing hormone receptor messenger ribonucleic acid expression in growth hormone-secreting pituitary adenoma with Gsalpha protein mutation.

    PubMed

    Sakai, Naoyuki; Kim, Kyongsong; Sanno, Naoko; Yoshida, Daizo; Teramoto, Akira; Shibasaki, Tamotsu

    2008-01-01

    Growth hormone-releasing hormone (GHRH) stimulates not only the synthesis and secretion of GH but also the proliferation of normal somatotrophs. The expression of GHRH receptor (GHRHR) is regulated by GHRH, both of which are known to be expressed in human GH-secreting pituitary adenoma cells. Somatic mutations in the subunit of Gsalpha protein (gsp), lead to the constitutive activation of adenylyl cyclase in pituitary adenomas that secrete GH. It has not been examined how gsp mutations influence GHRHR expression in GH-secreting adenomas. We therefore analyzed the expression levels of GHRHR messenger ribonucleic acid (mRNA) in GH-secreting pituitary adenomas focusing on a gsp mutation. Furthermore, we investigated the effect of GHRH on the expression of GHRHR mRNA in primary cultures of GH-secreting pituitary adenoma cells. GHRHR mRNA expression levels were significantly elevated in gsp mutation-positive GH-secreting adenomas compared with those in gsp mutation-negative ones. In primary-cultured GH-secreting adenoma cells, the increase of GH secretion in response to GHRH was shown in both gsp mutation-positive and -negative adenoma cells with a significantly higher response in the latter adenoma cells. GHRH increased GHRHR mRNA expression level in gsp mutation-negative adenoma cells while it was not influenced by GHRH in gsp mutation-positive adenoma cells. These results suggest that gsp mutations up-regulate GHRHR mRNA expression in GH-secreting pituitary adenoma cells, and that gsp mutations desensitize the adenoma cells to GHRH in terms of their GHRHR mRNA expression probably because of their saturation of GHRH signaling.

  8. Inhibition of growth of a prolactin-secreting pituitary tumor in rats by analogs of luteinizing hormone-releasing hormone and somatostatin.

    PubMed Central

    de Quijada, M G; Redding, T W; Coy, D H; Torres-Aleman, I; Schally, A V

    1983-01-01

    We investigated the effects of [D-Trp6]LH-RH [agonistic analog of luteinizing hormone-releasing hormone (LH-RH)], N-Ac-[D-p-Cl-Phe1,2,D-Trp3,D-Phe6,D-Ala10]LH-RH (antagonistic analog), and [D-5-methoxy-Trp8]somatostatin (somatostatin analog) on the growth of the prolactin and corticotropin-secreting pituitary tumor 7315a in female Buffalo rats. Chronic administration of [D-Trp6]LH-RH in a dose of 25 micrograms/day, starting 18 days after inoculation with the tumor, inhibited the growth of the pituitary tumor. Tumor weight and volume also were reduced when this agonist was administered 3 days after inoculation. The antagonistic LH-RH analog, injected in a dose of 50-100 micrograms for 14-24 days, also significantly inhibited the growth of pituitary tumor. Chronic administration of the somatostatin analog in a dose of 25 micrograms twice a day likewise decreased tumor weights in comparison with controls. The inhibition of pituitary tumor growth by LH-RH agonist, LH-RH antagonist, and somatostatin analog was accompanied by a decrease in serum prolactin levels. It was concluded that LH-RH agonist, LH-RH antagonist, and somatostatin analog can inhibit the growth of estrogen-dependent prolactin/corticotropin-secreting pituitary tumor in rats. PMID:6134284

  9. Growth hormone-releasing hormone receptor antagonists inhibit human gastric cancer through downregulation of PAK1–STAT3/NF-κB signaling

    PubMed Central

    Gan, Jinfeng; Ke, Xiurong; Jiang, Jiali; Dong, Hongmei; Yao, Zhimeng; Lin, Yusheng; Lin, Wan; Wu, Xiao; Yan, Shumei; Zhuang, Yixuan; Chu, Wai Kit; Cai, Renzhi; Zhang, Xianyang; Cheung, Herman S.; Block, Norman L.; Pang, Chi Pui; Schally, Andrew V.; Zhang, Hao

    2016-01-01

    Gastric cancer (GC) ranks as the fourth most frequent in incidence and second in mortality among all cancers worldwide. The development of effective treatment approaches is an urgent requirement. Growth hormone-releasing hormone (GHRH) and GHRH receptor (GHRH-R) have been found to be present in a variety of tumoral tissues and cell lines. Therefore the inhibition of GHRH-R was proposed as a promising approach for the treatment of these cancers. However, little is known about GHRH-R and the relevant therapy in human GC. By survival analyses of multiple cohorts of GC patients, we identified that increased GHRH-R in tumor specimens correlates with poor survival and is an independent predictor of patient prognosis. We next showed that MIA-602, a highly potent GHRH-R antagonist, effectively inhibited GC growth in cultured cells. Further, this inhibitory effect was verified in multiple models of human GC cell lines xenografted into nude mice. Mechanistically, GHRH-R antagonists target GHRH-R and down-regulate the p21-activated kinase 1 (PAK1)-mediated signal transducer and activator of transcription 3 (STAT3)/nuclear factor-κB (NF-κB) inflammatory pathway. Overall, our studies establish GHRH-R as a potential molecular target in human GC and suggest treatment with GHRH-R antagonist as a promising therapeutic intervention for this cancer. PMID:27930339

  10. Growth hormone releasing hexapeptide (GHRP-6) activates the inositol (1,4,5)-trisphosphate/diacylglycerol pathway in rat anterior pituitary cells.

    PubMed

    Mau, S E; Witt, M R; Bjerrum, O J; Saermark, T; Vilhardt, H

    1995-01-01

    Growth hormone-releasing hexapeptide (GHRP-6) is known to stimulate secretion of growth hormone (GH) in vivo and in vitro in a variety of species. However, the cellular effects of GHRP-6 remain largely unknown. We have tested the influence of GHRP-6 on the inositol phospholipid second messenger system in cultured anterior pituitary cells. Cultured pituitary cells responded upon challenge with GHRP-6 with a dose-dependent release of GH. Moreover, incubation of GHRP-6 with pituitary cell cultures labelled with myo-[3H]inositol resulted in a dose-dependent rise in [3H]inositol phosphates. Brief stimulation of pituitary cells with GHRP-6 increased phosphorylation of MBP4-14, a specific protein kinase C substrate, when incubated with the cytosol- or plasma membrane fraction from the stimulated cells. Furthermore, introduction of MBP4-14 into the cytosol in digitonin permeabilized pituitary cells caused increased phosphorylation of this substrate. GHRP-6 induced a rise in intracellular Ca2+ in individual somatotrophs loaded with the Ca2+ indicator, Fura-2. Preincubation (3 min) with somatostatin (SRIF) diminished the Ca2+ spike elicited by GHRP-6, while no effect of SRIF was observed when added simultaneously with GHRP-6. These results indicate that GHRP-6-stimulated GH-secretion involves the diacylglycerol/inositol(1,4,5)trisphosphate pathway with a resulting rise in cytosolic Ca2+.

  11. Time- and dose-dependent responses of brain histamine to intracerebroventricular and intraperitoneal administrations of growth hormone-releasing factor (GRF1-44).

    PubMed

    Cacabelos, R; Yamatodani, A; Fukui, H; Niigawa, H; Miyake, A; Watanabe, T; Nishimura, T; Wada, H

    1987-04-01

    Changes in the level of histamine (HA) in rat brain induced by intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administrations of growth hormone-releasing factor (GRF1-44) were studied. HA was determined by high-performance liquid chromatography (HPLC) in the anterior hypothalamic region, posterior hypothalamic region, median eminence, adenohypophysis, neurohypophysis, hippocampus and prefrontal cortex. GRF1-44 (1-10 micrograms, i.c.v.) induced significant time- and dose-dependent increases in the concentration of HA in the hypothalamo-hypophyseal system and time-dependent decrease of HA in the hippocampus. In contrast, after i.p. administration of GRF1-44 (10 micrograms) the level of HA in the hypothalamus tended to decrease but the total amount of H-1 receptors in the hypothalamo-hypophyseal system did not change. Circadian variations in the GRF-induced HA and growth hormone responses were also observed, responses being lower in the evening than in the morning. It is concluded that GRF interacts with HA at the central level to optimize the function of the somatotropinergic system.

  12. Kisspeptin stimulates growth hormone release by utilizing Neuropeptide Y pathways and is dependent on the presence of ghrelin

    USDA-ARS?s Scientific Manuscript database

    Although kisspeptin is the primary stimulator of gonadotropin releasing hormone secretion and therefore the hypothalamic-pituitary gonadal axis, new findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Central delivery of kisspep...

  13. Immunoreactive neuronal pathways of growth hormone-releasing hormone (GRH) in the brain and pituitary of the teleost Gadus morhua.

    PubMed

    Pan, J X; Lechan, R M; Lin, H D; Jackson, I M

    1985-01-01

    Using an antiserum directed against the C-terminus of hGRH(1-44)NH2 and another recognizing the mid portion to C-terminal of hGRH(1-40)OH, we identify two immunocytochemically distinct GRH-immunoreactive systems in the brain of the codfish, Gadus morhua. The antiserum directed against GRF(1-44)NH2 stains cell bodies exclusively in the rostral pars distalis. The other antiserum immunoreactive with GRF(1-40)OH reacts with a population of parvocellular and magnocellular neuronal cell bodies in the hypothalamus and with two major axonal pathways which project toward the median eminence and terminate primarily in the pars nervosa. These results indicate the presence of at least two forms of hGRH-like peptides in the teleost which may have different roles in the regulation of pituitary function.

  14. Central administration of growth hormone-releasing hormone triggers downstream movement and schooling behavior of chum salmon (Oncorhynchus keta) fry in an artificial stream.

    PubMed

    Ojima, Daisuke; Iwata, Munehico

    2009-03-01

    Anadromous salmonids migrate downstream to the ocean (downstream migration). The neuroendocrine mechanism of triggering the onset of downstream migration is not well known. We investigated the effects of 14 chemicals, including neuropeptides, pineal hormones, neurotransmitters, and neuromodulators (growth hormone-releasing hormone: GHRH, thyrotropin-releasing hormone, corticotropin-releasing hormone: CRH, gonadotropin-releasing hormone, melatonin, N-acetyl serotonin, serotonin, beta-endorphin, enkephalin, dopamine, norepinephrine, epinephrine, acetylcholine, and histamine) on the onset of downstream migration in chum salmon (Oncorhynchus keta) fry. We defined downstream migration as a downstream movement (negative rheotaxis) with schooling behavior and counted the number of downstream movements and school size in experimental circulation tanks. An intracerebroventricular injection of GHRH, CRH, melatonin, N-acetyl serotonin, or serotonin stimulated the number of downstream movements. However, GHRH was the only chemical that also stimulated an increase in schooling behavior. These results suggest that CRH, melatonin, N-acetyl serotonin, and serotonin are involved in the stimulation of downstream movement in chum salmon, while GHRH stimulates both downstream movement and schooling behavior.

  15. Polymorphisms of the porcine cathepsins, growth hormone-releasing hormone and leptin receptor genes and their association with meat quality traits in Ukrainian Large White breed.

    PubMed

    Balatsky, Viktor; Bankovska, Irina; Pena, Ramona N; Saienko, Artem; Buslyk, Tetyana; Korinnyi, Sergii; Doran, Olena

    2016-06-01

    Cathepsins, growth hormone-releasing hormone (GHRH) and leptin receptor (LEPR) genes have been receiving increasing attention as potential markers for meat quality and pig performance traits. This study investigated the allele variants in four cathepsin genes (CTSB, CTSK, CTSL, CTSS), GHRH and LEPR in pure-bred Ukrainian Large White pigs and evaluated effects of the allele variants on meat quality characteristics. The study was conducted on 72 pigs. Genotyping was performed using PCR-RFLP technique. Meat quality characteristics analysed were intramuscular fat content, tenderness, total water content, ultimate pH, crude protein and ashes. A medium level of heterozygosity values was established for GHRH and LEPR genes which corresponded to very high levels of informativeness indexes. Cathepsins CTSL, CTSB and CTSK had a low level of heterozygosity, and CTSS did not segregate in this breed. Association studies established that intramuscular fat content and tenderness were affected by the allele variance in GHRH and LEPR but not by CTSB and CTSL genes. The GHRH results could be particularly relevant for the production of lean prime cuts as the A allele is associated with both, a lower meat fat content and better tenderness values, which are two attributes highly regarded by consumers. Results of this study suggest that selective breeding towards GHRH/AA genotype would be particularly useful for improving meat quality characteristics in the production systems involving lean Large White lines, which typically have less than 2 % intramuscular fat content.

  16. Growth hormone-releasing hormone antagonist inhibits the invasiveness of human endometrial cancer cells by down-regulating twist and N-cadherin expression

    PubMed Central

    Wu, Hsien-Ming; Huang, Hong-Yuan; Schally, Andrew V; Chao, Angel; Chou, Hung-Hsueh; Leung, Peter C.K.; Wang, Hsin-Shih

    2017-01-01

    More than 25% of patients diagnosed with endometrial carcinoma have invasive primary cancer accompanied by metastases. Growth hormone-releasing hormone (GHRH) plays an important role in reproduction. Here, we examined the effect of a GHRH antagonist on the motility of endometrial cancer cells and the mechanisms of action of the antagonist in endometrial cancer. Western blotting and immunohistochemistry (IHC) were used to determine the expression of the GHRH receptor protein. The activity of Twist and N-cadherin was determined by Western blotting. Cell motility was assessed by an invasion and migration assay. GHRH receptor siRNA was applied to knockdown the GHRH receptor in endometrial cancer cells. The GHRH antagonist inhibited cell motility in a dose-dependent manner. The GHRH antagonist inhibited cell motility and suppressed the expression of Twist and N-cadherin, and the suppression was abolished by GHRH receptor siRNA pretreatment. Moreover, the inhibition of Twist and N-cadherin with Twist siRNA and N-cadherin siRNA, respectively, suppressed cell motility. Our study indicates that the GHRH antagonist inhibited the cell motility of endometrial cancer cells through the GHRH receptor via the suppression of Twist and N-cadherin. Our findings represent a new concept in the mechanism of GHRH antagonist-suppressed cell motility in endometrial cancer cells and suggest the possibility of exploring GHRH antagonists as potential therapeutics for the treatment of human endometrial cancer. PMID:28032599

  17. Set-up of large laboratory-scale chromatographic separations of poly(ethylene glycol) derivatives of the growth hormone-releasing factor 1-29 analogue.

    PubMed

    Piquet, G; Gatti, M; Barbero, L; Traversa, S; Caccia, P; Esposito, P

    2002-01-25

    In this paper we report the scale-up of the purification of poly(ethylene glycol) (PEG) derivatives of the growth hormone-releasing factor 1-29, from laboratory scale (100 mg of bulk starting material) to larger scale (3 g of bulk), through the use of a cation-exchange TSK-SP-5PW chromatographic column. A one-step purification process capable of purifying large amounts of mono-PEGylated GRF species from the crude reaction mixture was developed. A simple, straightforward stepwise gradient elution separation was developed at laboratory scale and then scaled up with a larger column packed with a chromatographic resin with the same chemistry which maintained the laboratory-scale separation profile. Active material recovery and material purity remained constant through the scale-up from the 13-microm stationary phase to the 25-microm larger column. Overall, the gram GRF equivalent/batch process scale showed to be quite reproducible, and could be considered as a good platform for scale up to production scale.

  18. Growth hormone-releasing hormone-producing pancreatic neuroendocrine tumor in a multiple endocrine neoplasia type 1 family with an uncommon phenotype.

    PubMed

    Sala, Elisa; Ferrante, Emanuele; Verrua, Elisa; Malchiodi, Elena; Mantovani, Giovanna; Filopanti, Marcello; Ferrero, Stefano; Pietrabissa, Andrea; Vanoli, Alessandro; La Rosa, Stefano; Zatelli, Maria C; Beck-Peccoz, Paolo; Verga, Uberta

    2013-07-01

    The objective of this study was to describe a multiple endocrine neoplasia type 1 (MEN1) family characterized by primary hyperparathyroidism, in association with acromegaly because of ectopic growth hormone-releasing hormone (GHRH) secretion by a pancreatic neuroendocrine tumor in a young man and with a bronchial carcinoid in his mother. We investigate the clinical, radiological imaging, histopathologic findings, and therapy. An 18-year-old man successfully underwent subtotal parathyroidectomy for primary hyperparathyroidism. A subsequent genetic analysis showed a MEN1 gene mutation. Three years later, acromegaly because of ectopic GHRH secretion was diagnosed (pituitary MRI negative and elevated GHRH levels). A search for an ectopic tumor was unsuccessful and somatostatin analog therapy was started. Successively, scintigraphy with somatostatin analogs (68-Ga-DOTATOC-PET) showed three focal areas in the pancreatic tail. Distal pancreatectomy showed multiple pancreatic neuroendocrine tumors and hormonal status was normalized. Afterwards, the evaluation of the patient's mother, carrying the same mutation, indicated a primary hyperparathyroidism and a 4 cm lung mass. The patient underwent subtotal pneumonectomy and the histological analysis was consistent with the diagnosis of a typical bronchial carcinoid. In conclusion, an atypical phenotype may be recorded in MEN1 families, thus emphasizing the importance of the new imaging and surgical techniques in the diagnosis and treatment of such a rare disease.

  19. Effect of aging on GHRF-induced growth hormone release from anterior pituitary cells in primary culture

    SciTech Connect

    Spik, K.W.; Boyd, R.L.; Sonntag, W.E.

    1991-03-01

    Five criteria were developed to validate the primary cell culture model for comparison of GRF-induced release of growth hormone in pituitary tissue from aging animals. Pituitaries from young (5-mo), middle-aged (14-mo), and old (24-mo) male Fischer 344 rats were dispersed using either trypsin/trypsin inhibitor or dispase and compared with respect to the number of pituitary cells recovered, cell viability, 3H-leucine incorporation into total protein, time course for recovery of optimal response to GRF, and the dose-relationship for GRF-induced release of growth hormone 2, 4, and 6 days after dispersal. Results indicated that direct comparison of cellular responses between tissues from young, middle-aged, and old rats in primary cell culture is confounded by variations in time for recovery of optimal responses, the effects of the enzymes used for dispersal, and the methods used to express the data.

  20. Site-specific PEGylation for high-yield preparation of Lys(21)-amine PEGylated growth hormone-releasing factor (GRF) (1-29) using a GRF(1-29) derivative FMOC-protected at Tyr(1) and Lys(12).

    PubMed

    Youn, Yu Seok; Lee, Kang Choon

    2007-01-01

    PEGylation has been viewed as an effective means of overcoming the therapeutic restriction of growth hormone-releasing factor (1-29) (GRF(1-29)) due to its short biological lifetime caused by severe proteolysis and rapid glomerular filtration. Of three isomers according to the PEGylation sites (Tyr1, Lys12, or Lys21), PEGylated GRF(1-29) at Lys21-amine (Lys21-PEG-GRF(1-29)) was shown to have the highest bioactivity. In this report, we propose a unique two-step site-specific PEGylation method capable of producing only Lys21-PEG-GRF(1-29) with a single composition in high yield using a GRF(1-29) derivative protected at Tyr1 and Lys12 and remained available at Lys21 (FMOC1,12-GRF(1-29)). The first step of this reaction involved the PEG attachment to FMOC1,12-GRF(1-29), and the second step involved the removal of FMOC moieties. This PEGylation process was optimized at the following conditions: 0.2-0.3% (v/v) triethylamine concentration, 5.0-6.0-fold molar amount of PEG, reaction temperature of 25-45 degrees C, and reaction time of 30 min. Under these conditions, the maximum yield of Lys21-PEG-GRF(1-29) produced was ca. approximately 95%, 6.3-fold higher than that by nonspecific PEGylation at pH 8.5. Significantly, this site-specific Lys21-PEG-GRF(1-29) was found to have greatly increased resistance to rat plasma, liver, and kidney homogenates, with 7.0-, 25.4-, and 16.4-fold longer half-lives vs GRF(1-29), respectively. Furthermore, 125I-Lys21-PEG-GRF(1-29) displayed significantly reduced liver and kidney distributions and extended blood presence vs 125I-GRF(1-29) in rats. Due to these benefits, Lys21-PEG-GRF(1-29) displayed an enhanced initial growth hormone release in vivo despite having 15% remaining activity in vitro. This devised PEGylation method using an FMOC-protection/deprotection strategy would provide great usefulness for PEGylating bioactive peptides in terms of improved biological potency, elevated production yield, and a uniform composition.

  1. Inhibition of L-dopa induced growth hormone release in normal and diabetic subjects by glucose administration.

    PubMed

    Vigas, M; Klimes, I; Jurcovicova, J; Kolesar, P; Repcekova-Jezova, D

    1977-12-01

    Administration of L-dopa 1 g induced an increase of plasma growth hormone (GH) levels in seven of ten healthy volunteers and in six of ten hyperglycemic insulin-dependent diabetic subjects; the maximal GH response was higher in normal subjects. Addition of 100 g glucose orally to the L-dopa completely abolished the GH response of both groups. The difference between the effect of endogenous hyperglycemia and the effect of a sudden increase of blood sugar after glucose administration on L-dopa induced GH release in diabetic subjects may be explain by the resetting of the hypothalamic control for pituitary GH release to higher levels of blood glucose.

  2. 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

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

    PubMed

    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

    2015-11-03

    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.

  4. Effects of a growth hormone-releasing hormone antagonist on telomerase activity, oxidative stress, longevity, and aging in mice.

    PubMed

    Banks, William A; Morley, John E; Farr, Susan A; Price, Tulin O; Ercal, Nuran; Vidaurre, Irving; Schally, Andrew V

    2010-12-21

    Both deficiency and excess of growth hormone (GH) are associated with increased mortality and morbidity. GH replacement in otherwise healthy subjects leads to complications, whereas individuals with isolated GH deficiency such as Laron dwarfs show increased life span. Here, we determined the effects of treatment with the GH-releasing hormone (GHRH) receptor antagonist MZ-5-156 on aging in SAMP8 mice, a strain that develops with aging cognitive deficits and has a shortened life expectancy. Starting at age 10 mo, mice received daily s.c. injections of 10 μg/mouse of MZ-5-156. Mice treated for 4 mo with MZ-5-156 showed increased telomerase activity, improvement in some measures of oxidative stress in brain, and improved pole balance, but no change in muscle strength. MZ-5-156 improved cognition after 2 mo and 4 mo, but not after 7 mo of treatment (ages 12, 14 mo, and 17 mo, respectively). Mean life expectancy increased by 8 wk with no increase in maximal life span, and tumor incidence decreased from 10 to 1.7%. These results show that treatment with a GHRH antagonist has positive effects on some aspects of aging, including an increase in telomerase activity.

  5. Effects of a growth hormone-releasing hormone antagonist on telomerase activity, oxidative stress, longevity, and aging in mice

    PubMed Central

    Banks, William A.; Morley, John E.; Farr, Susan A.; Price, Tulin O.; Ercal, Nuran; Vidaurre, Irving; Schally, Andrew V.

    2010-01-01

    Both deficiency and excess of growth hormone (GH) are associated with increased mortality and morbidity. GH replacement in otherwise healthy subjects leads to complications, whereas individuals with isolated GH deficiency such as Laron dwarfs show increased life span. Here, we determined the effects of treatment with the GH-releasing hormone (GHRH) receptor antagonist MZ-5-156 on aging in SAMP8 mice, a strain that develops with aging cognitive deficits and has a shortened life expectancy. Starting at age 10 mo, mice received daily s.c. injections of 10 μg/mouse of MZ-5-156. Mice treated for 4 mo with MZ-5-156 showed increased telomerase activity, improvement in some measures of oxidative stress in brain, and improved pole balance, but no change in muscle strength. MZ-5-156 improved cognition after 2 mo and 4 mo, but not after 7 mo of treatment (ages 12, 14 mo, and 17 mo, respectively). Mean life expectancy increased by 8 wk with no increase in maximal life span, and tumor incidence decreased from 10 to 1.7%. These results show that treatment with a GHRH antagonist has positive effects on some aspects of aging, including an increase in telomerase activity. PMID:21135231

  6. Relationship of adiponectin to endogenous GH pulse secretion parameters in response to stimulation with a growth hormone releasing factor.

    PubMed

    Makimura, H; Stanley, T L; Chen, C Y; Branch, K L; Grinspoon, S K

    2011-06-01

    Obesity is associated with both reduced growth hormone (GH) and adiponectin. However, the relationship between adiponectin and parameters of endogenous GH secretion remains unknown. The aim of this study was to determine the relationship between total and high molecular weight (HMW) adiponectin and parameters of endogenous pulsatile GH secretion and the effects of tesamorelin, a synthetic GH releasing hormone (GHRH(1-44)), on total and HMW adiponectin. A 2-week interventional study with tesamorelin was conducted at an academic medical center in 13 men with BMI 20-35 kg/m(2). Overnight frequent blood sampling and measurement of total and HMW adiponectin at baseline and after treatment were performed to assess the effects of augmenting endogenous pulsatile GH secretion. Total, but not HMW, adiponectin was positively associated with log(10)Peak GH area (r=+0.73; P=0.005), basal GH secretion (r=+0.67; P=0.01), and total GH production (r=+0.57; P=0.04), but was not associated with the number of secretion events (P=0.85). Two-week treatment with tesamorelin increased endogenous GH release and IGF-1, but neither total (change -0.16±0.64; P=0.40), nor HMW (change +0.03±0.70; P=0.87) adiponectin changed significantly with treatment. Sub-analyses in overweight and obese men yielded similar results. Our study demonstrates a strong relationship between specific parameters of endogenous GH pulsatility and adiponectin. However, short-term augmentation of GH pulsatility over 2-weeks does not change adiponectin. Therefore, the relationship between GH and adiponectin is most likely mediated by specific covariates related to adiposity or other factors. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Relationship between nitric oxide- and calcium-dependent signal transduction pathways in growth hormone release from dispersed goldfish pituitary cells.

    PubMed

    Chang, John P; Sawisky, Grant R; Davis, Philip J; Pemberton, Joshua G; Rieger, Aja M; Barreda, Daniel R

    2014-09-15

    Nitric oxide (NO) and Ca(2+) are two of the many intracellular signal transduction pathways mediating the control of growth hormone (GH) secretion from somatotropes by neuroendocrine factors. We have previously shown that the NO donor sodium nitroprusside (SNP) elicits Ca(2+) signals in identified goldfish somatotropes. In this study, we examined the relationships between NO- and Ca(2+)-dependent signal transduction mechanisms in GH secretion from primary cultures of dispersed goldfish pituitary cells. Morphologically identified goldfish somatotropes stained positively for an NO-sensitive dye indicating they may be a source of NO production. In 2h static incubation experiments, GH release responses to the NO donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP) were attenuated by CoCl2, nifedipine, verapamil, TMB-8, BHQ, and KN62. In column perifusion experiments, the ability of SNP to induce GH release was impaired in the presence of TMB-8, BHQ, caffeine, and thapsigargin, but not ryanodine. Caffeine-elicited GH secretion was not affected by the NO scavenger PTIO. These results suggest that NO-stimulated GH release is dependent on extracellular Ca(2+) availability and voltage-sensitive Ca(2+) channels, as well as intracellular Ca(2+) store(s) that possess BHQ- and/or thapsigargin-inhibited sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases, as well as TMB-8- and/or caffeine-sensitive, but not ryanodine-sensitive, Ca(2+)-release channels. Calmodulin kinase-II also likely participates in NO-elicited GH secretion but caffeine-induced GH release is not upstream of NO production. These findings provide insights into how NO actions many integrate with Ca(2+)-dependent signalling mechanisms in goldfish somatotropes and how such interactions may participate in the GH-releasing actions of regulators that utilize both NO- and Ca(2+)-dependent transduction pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. QSAR models for predicting the activity of non-peptide luteinizing hormone-releasing hormone (LHRH) antagonists derived from erythromycin A using quantum chemical properties.

    PubMed

    Fernández, Michael; Caballero, Julio

    2007-04-01

    Multiple linear regression (MLR) combined with genetic algorithm (GA) and Bayesian-regularized Genetic Neural Networks (BRGNNs) were used to model the binding affinity (pK(I)) of 38 11,12-cyclic carbamate derivatives of 6-O-methylerythromycin A for the Human Luteinizing Hormone-Releasing Hormone (LHRH) receptor using quantum chemical descriptors. A multiparametric MLR equation with good statistical quality was obtained that describes the features relevant for antagonistic activity when the substituent at the position 3 of the erythronolide core was varied. In addition, four-descriptor linear and nonlinear models were established for the whole dataset. Such models showed high statistical quality. However, the BRGNN model was better than the linear model according to the external validation process. In general, our linear and nonlinear models reveal that the binding affinity of the compounds studied for the LHRH receptor is modulated by electron-related terms.

  9. Subcutaneous octreotide treatment of a growth hormone-releasing hormone-secreting bronchial carcinoid: superiority of continuous versus intermittent administration to control hormonal secretion.

    PubMed

    Lefebvre, S; De Paepe, L; Abs, R; Rahier, J; Selvais, P; Maiter, D

    1995-09-01

    Diagnosis of ectopic acromegaly was made in a 21-year-old female patient who 3 years before had undergone a right pneumectomy for a disseminated bronchial carcinoid. Plasma growth hormone-releasing hormone (GHRH) concentrations were markedly elevated (6440 ng/l; normal value < 100 ng/l), as were serum GH (187 micrograms/l; normal < 5 micrograms/l) and plasma insulin-like growth factor I (IGF-I) levels (6.7 U/ml; normal < 2 U/ml). Retrospective immunohistochemical examination of the carcinoid tumor was positive for GHRH and the tumoral content of GHRH was 2130 ng/g wet weight. Subcutaneous treatment with octreotide was begun and first resulted in a profound inhibition of GH hypersecretion, normalization of plasma IGF-I and only partial reduction of GHRH concentrations. However, the initial dose of 3 x 100 micrograms had to be increased gradually to 4 x 750 micrograms because of a progressive deterioration of the hormonal control. After 15 months of intermittent therapy, octreotide was administered by continuous sc infusion. This treatment improved compliance, allowed the daily dose of octreotide to be reduced to 1500 micrograms and normalized serum GH levels. A near-normalization of the plasma IGF-I concentrations was also obtained, whereas the suppression of plasma GHRH concentrations remained incomplete. Despite favorable evolution of the endocrine parameters, intramedullar metastases were diagnosed and required radiation therapy. This observation emphasizes the superiority of continuous over intermittent administration of octreotide in the treatment of ectopic acromegaly. It also shows that the somatostatin analog acts more at the pituitary level to inhibit GH secretion than at the site of the neuroendocrine tumor.

  10. Exocytosis sensitivity to growth hormone-releasing hormone in subsets of GH cells in rats under different corticosterone conditions. Ultrastructural study using microwave irradiation for fixation and immunocytochemistry.

    PubMed

    Ozawa, Hitoshi; Han, Fang; Kawata, Mitsuhiro

    2004-12-01

    Growth hormone (GH) cells in the rat anterior pituitary have been morphologically classified into three subtypes: type I (mature) containing large secretory granules about 350 nm in diameter, type II (intermediate) containing a mixture of large and small granules, and type III (immature) containing small granules about 150 nm in diameter. However, the functional implications of morphological heterogeneity, especially the different sensitivities to growth hormone-releasing hormone (GRH) under different corticosteroid conditions have not been elucidated to date. In the present study, by application of microwave irradiation (MWI) for fixation and immunocytochemistry, new findings of the exocytotic response have been revealed among the subsets of GH cells following adrenalectomy (ADX), corticosterone treatment and/or GRH treatment. The MWI gave effective results for fixation, especially for the permeability of the fixative, and showed good results for immunoelectron microscopy using the protein-A gold method. Moreover, the use of MWI greatly shortened the fixation, processing and immunolabeling times without compromising the quality of ultrastructural preservation and the specificity of labeling. The number of exocytotic figures was low in all subtypes of GH cells in the sham-operated control rats. GRH treatment induced a significant increase in exocytosis in each subtype of GH cells, particularly in type I (mature) and type II (intermediate) GH cells in the control rats. GRH injection to rats for 4 days after ADX also showed an increase in exocytosis, but the degree was significantly less in comparison with the GRH injection in the control group. Corticosterone replacement given to ADX rats induced a clear recovery of the exocytotic response to GRH to the control level. Serum GH content measured by radioimmunoassay correlated with these morphological results. These results suggest that the secretion of GH stimulated by GRH is closely related to corticosteroids, and

  11. Plasmid-mediated growth hormone-releasing hormone efficacy in reducing disease associated with Mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus infection.

    PubMed

    Thacker, E L; Holtkamp, D J; Khan, A S; Brown, P A; Draghia-Akli, R

    2006-03-01

    The purpose of this study was to determine the effects of plasmid-mediated growth hormone releasing hormone (GHRH) supplementation on the clinical outcomes of pigs vaccinated against and challenged with either Mycoplasma hyopneumonia (M. hyo) and/or with porcine reproductive and respiratory syndrome (PRRS) virus. Before the first vaccination, pigs received a single i.m. injection of 0.625 mg of a porcine GHRH-expressing plasmid followed by electroporation of the injection site. Pigs were vaccinated at 2-wk intervals, challenged with either M. hyo and/or PRRS virus 2-wk after the second vaccination, and necropsied at 17 and 36 d after challenge. Clinical parameters associated with M. hyo challenge were improved with the GHRH treatment. Average daily gain between challenge and necropsy was improved (P = 0.04). Respiratory scores for M. hyo-challenged pigs tended to be lower in GHRH-treated animals compared to controls, and coughing scores were improved by the treatment (P = 0.01). Macroscopic lesions associated with M. hyo infection pneumonia were fewer in the group that received the GHRH-expressing plasmid. No differences between treatment groups in the macroscopic pneumonia associated with PRRS virus were observed. No differences in serum antibodies to M. hyo or PRRS virus were observed with GHRH treatment. Nevertheless, IgG in the bronchioalveolar lavage was increased by the GHRH treatment in M. hyo-challenged animals (P < 0.03). The results of this study suggest that GHRH supplementation before vaccination may enhance the protection against M. hyo-induced pneumonia and that a single dose of GHRH-expressing plasmid was sufficient to elicit an improved clinical outcome in this disease challenge model.

  12. Effects of growth hormone-releasing hormone on sleep and brain interstitial fluid amyloid-β in an APP transgenic mouse model.

    PubMed

    Liao, Fan; Zhang, Tony J; Mahan, Thomas E; Jiang, Hong; Holtzman, David M

    2015-07-01

    Alzheimer's disease (AD) is a neurodegenerative disorder characterized by impairment of cognitive function, extracellular amyloid plaques, intracellular neurofibrillary tangles, and synaptic and neuronal loss. There is substantial evidence that the aggregation of amyloid β (Aβ) in the brain plays a key role in the pathogenesis of AD and that Aβ aggregation is a concentration dependent process. Recently, it was found that Aβ levels in the brain interstitial fluid (ISF) are regulated by the sleep-wake cycle in both humans and mice; ISF Aβ is higher during wakefulness and lower during sleep. Intracerebroventricular infusion of orexin increased wakefulness and ISF Aβ levels, and chronic sleep deprivation significantly increased Aβ plaque formation in amyloid precursor protein transgenic (APP) mice. Growth hormone-releasing hormone (GHRH) is a well-documented sleep regulatory substance which promotes non-rapid eye movement sleep. GHRHR(lit/lit) mice that lack functional GHRH receptor have shorter sleep duration and longer wakefulness during light periods. The current study was undertaken to determine whether manipulating sleep by interfering with GHRH signaling affects brain ISF Aβ levels in APPswe/PS1ΔE9 (PS1APP) transgenic mice that overexpress mutant forms of APP and PSEN1 that cause autosomal dominant AD. We found that intraperitoneal injection of GHRH at dark onset increased sleep and decreased ISF Aβ and that delivery of a GHRH antagonist via reverse-microdialysis suppressed sleep and increased ISF Aβ. The diurnal fluctuation of ISF Aβ in PS1APP/GHRHR(lit/lit) mice was significantly smaller than that in PS1APP/GHRHR(lit/+) mice. However despite decreased sleep in GHRHR deficient mice, this was not associated with an increase in Aβ accumulation later in life. One of several possibilities for the finding is the fact that GHRHR deficient mice have GHRH-dependent but sleep-independent factors which protect against Aβ deposition.

  13. Qualitative identification of growth hormone-releasing hormones in human plasma by means of immunoaffinity purification and LC-HRMS/MS.

    PubMed

    Knoop, Andre; Thomas, Andreas; Fichant, Eric; Delahaut, Philippe; Schänzer, Wilhelm; Thevis, Mario

    2016-05-01

    The use of growth hormone-releasing hormones (GHRHs) is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA). The aim of the present study was to develop a method for the simultaneous detection of four different GHRHs and respective metabolites from human plasma by means of immunoaffinity purification and subsequent nano-ultrahigh performance liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry. The target analytes included Geref (Sermorelin), CJC-1293, CJC-1295, and Egrifta (Tesamorelin) as well as two metabolites of Geref and CJC-1293, which were captured from plasma samples using a polyclonal GHRH antibody in concert with protein A/G monolithic MSIA™ D.A.R.T.'S® (Disposable Automation Research Tips) prior to separation and detection. The method was fully validated and found to be fit for purpose considering the parameters specificity, linearity, recovery (19-37%), lower limit of detection (<50 pg/mL), imprecision (<20%), and ion suppression/enhancement effects. The analytes' stability and metabolism were elucidated using in vitro and in vivo approaches. EDTA blood samples were collected from rats 2, 4, and 8 h after intravenous administration of GHRH (one compound per test animal). All intact substances were detected for at least 4 h but no anticipated metabolite was confirmed in laboratory rodents' samples; conversely, a Geref metabolite (GHRH3-29) was found in a human plasma sample collected after subcutaneous injection of the drug to a healthy male volunteer. The obtained results demonstrate that GHRHs are successfully detected in plasma using an immunoaffinity-mass spectrometry-based method, which can be applied to sports drug testing samples. Further studies are however required and warranted to account for potential species-related differences in metabolism and elimination of the target analytes.

  14. Enhanced Anti-Tumoral Activity of Methotrexate-Human Serum Albumin Conjugated Nanoparticles by Targeting with Luteinizing Hormone-Releasing Hormone (LHRH) Peptide

    PubMed Central

    Taheri, Azade; Dinarvand, Rassoul; Atyabi, Fatemeh; Ahadi, Fatemeh; Nouri, Farank Salman; Ghahremani, Mohammad Hossein; Ostad, Seyed Nasser; Borougeni, Atefeh Taheri; Mansoori, Pooria

    2011-01-01

    Active targeting could increase the efficacy of anticancer drugs. Methotrexate-human serum albumin (MTX-HSA) conjugates, functionalized by luteinizing hormone-releasing hormone (LHRH) as targeting moieties, with the aim of specifically targeting the cancer cells, were prepared. Owing to the high expression of LHRH receptors in many cancer cells as compared to normal cells, LHRH was used as the targeting ligand in this study. LHRH was conjugated to MTX-HSA nanoparticles via a cross-linker. Three types of LHRH targeted nanoparticles with a mean particle size between 120–138 nm were prepared. The cytotoxicity of LHRH targeted and non-targeted nanoparticles were determined on the LHRH positive and negative cell lines. The internalization of the targeted and non-targeted nanoparticles in LHRH receptor positive and negative cells was investigated using flow cytometry analysis and fluorescence microscopy. The cytotoxicity of the LHRH targeted nanoparticles on the LHRH receptor positive cells were significantly more than non-targeted nanoparticles. LHRH targeted nanoparticles were also internalized by LHRH receptor positive cells significantly more than non-targeted nanoparticles. There were no significant differences between the uptake of targeted and non-targeted nanoparticles to the LHRH receptor negative cells. The active targeting procedure using LHRH targeted MTX-HSA nanoparticles could increase the anti-tumoral activity of MTX. PMID:21845098

  15. Diagnostic challenges and management of a patient with acromegaly due to ectopic growth hormone-releasing hormone secretion from a bronchial carcinoid tumour

    PubMed Central

    Kyriakakis, Nikolaos; Trouillas, Jacqueline; Dang, Mary N; Lynch, Julie; Belchetz, Paul; Korbonits, Márta

    2017-01-01

    Summary A male patient presented at the age of 30 with classic clinical features of acromegaly and was found to have elevated growth hormone levels, not suppressing during an oral glucose tolerance test. His acromegaly was originally considered to be of pituitary origin, based on a CT scan, which was interpreted as showing a pituitary macroadenoma. Despite two trans-sphenoidal surgeries, cranial radiotherapy and periods of treatment with bromocriptine and octreotide, his acromegaly remained active clinically and biochemically. A lung mass was discovered incidentally on a chest X-ray performed as part of a routine pre-assessment for spinal surgery 5 years following the initial presentation. This was confirmed to be a bronchial carcinoid tumour, which was strongly positive for growth hormone-releasing hormone (GHRH) and somatostatin receptor type 2 by immunohistochemistry. The re-examination of the pituitary specimens asserted the diagnosis of pituitary GH hyperplasia. Complete resolution of the patient’s acromegaly was achieved following right lower and middle lobectomy. Seventeen years following the successful resection of the bronchial carcinoid tumour the patient remains under annual endocrine follow-up for monitoring of the hypopituitarism he developed after the original interventions to his pituitary gland, while there has been no evidence of active acromegaly or recurrence of the carcinoid tumour. Ectopic acromegaly is extremely rare, accounting for <1% of all cases of acromegaly. Our case highlights the diagnostic challenges differentiating between ectopic acromegaly and acromegaly of pituitary origin and emphasises the importance of avoiding unnecessary pituitary surgery and radiotherapy. The role of laboratory investigations, imaging and histology as diagnostic tools is discussed. Learning points: Ectopic acromegaly is rare, accounting for less than 1% of all cases of acromegaly. Ectopic acromegaly is almost always due to extra-pituitary GHRH secretion

  16. Noradrenergic regulation of hypothalamic cells that produce growth hormone-releasing hormone and somatostatin and the effect of altered adiposity in sheep.

    PubMed

    Iqbal, J; Manley, T R; Yue, Q; Namavar, M R; Clarke, I J

    2005-06-01

    The growth hormone (GH) axis is sensitive to alteration in body weight and there is evidence that central noradrenergic systems regulate neurones that produce growth hormone-releasing hormone (GHRH) and somatostatin (SRIF). This study reports semiquantitative estimates of the noradrenergic input to neuroendocrine GHRH and SRIF neurones in the sheep of different body weights. We also studied the effects of altered body weight on expression of dopamine beta-hydroxylase (DBH), the enzyme that produces noradrenalin from dopamine. Ovariectomised ewes were made Lean (39.6 +/- 2.6 kg; Mean +/- SEM) by dietary restriction, whereas Normally Fed animals (61.2 +/- 0.8 kg) were maintained on a regular diet. Brains were perfused for immunohistochemistry and in situ hybridisation. The Mean +/- SEM number of GHRH-immunoreactive (-IR) cells was lower in Normally Fed (65 +/- 7) than in Lean (115 +/- 14) animals, whereas the number of SRIF-IR cells was similar in the two groups (Normally Fed, 196 +/- 17; Lean 230 +/- 21). Confocal microscopic analysis revealed that the percentage of GHRH-IR cells (Normally Fed 36 +/- 1.5% versus Lean 32 +/- 4.6%) and percentage of SRIF-IR cells (Normally Fed 30 +/- 40.4% versus Lean 32 +/- 2.3%) contacted by noradrenergic fibres did not change with body weight. FluoroGold retrograde tracer injections confirmed that noradrenergic projections to the arcuate nucleus are from ventrolateral medulla and noradrenergic projections to periventricular nucleus arise from the ventrolateral medulla, nucleus of solitary tract, locus coeruleus (LC) and the parabrachial nucleus (PBN). DBH expressing cells were identified using immunohistochemistry and in situ hybridisation and the level of expression (silver grains/cell) quantified by image analysis. The number of DBH cells was similar in Normally Fed and Lean animals, but the level of expression/cell was lower (P < 0.02) in the PBN and LC of Lean animals. These results provide an anatomical basis for the

  17. Diagnostic challenges and management of a patient with acromegaly due to ectopic growth hormone-releasing hormone secretion from a bronchial carcinoid tumour.

    PubMed

    Kyriakakis, Nikolaos; Trouillas, Jacqueline; Dang, Mary N; Lynch, Julie; Belchetz, Paul; Korbonits, Márta; Murray, Robert D

    2017-01-01

    A male patient presented at the age of 30 with classic clinical features of acromegaly and was found to have elevated growth hormone levels, not suppressing during an oral glucose tolerance test. His acromegaly was originally considered to be of pituitary origin, based on a CT scan, which was interpreted as showing a pituitary macroadenoma. Despite two trans-sphenoidal surgeries, cranial radiotherapy and periods of treatment with bromocriptine and octreotide, his acromegaly remained active clinically and biochemically. A lung mass was discovered incidentally on a chest X-ray performed as part of a routine pre-assessment for spinal surgery 5 years following the initial presentation. This was confirmed to be a bronchial carcinoid tumour, which was strongly positive for growth hormone-releasing hormone (GHRH) and somatostatin receptor type 2 by immunohistochemistry. The re-examination of the pituitary specimens asserted the diagnosis of pituitary GH hyperplasia. Complete resolution of the patient's acromegaly was achieved following right lower and middle lobectomy. Seventeen years following the successful resection of the bronchial carcinoid tumour the patient remains under annual endocrine follow-up for monitoring of the hypopituitarism he developed after the original interventions to his pituitary gland, while there has been no evidence of active acromegaly or recurrence of the carcinoid tumour. Ectopic acromegaly is extremely rare, accounting for <1% of all cases of acromegaly. Our case highlights the diagnostic challenges differentiating between ectopic acromegaly and acromegaly of pituitary origin and emphasises the importance of avoiding unnecessary pituitary surgery and radiotherapy. The role of laboratory investigations, imaging and histology as diagnostic tools is discussed. Ectopic acromegaly is rare, accounting for less than 1% of all cases of acromegaly.Ectopic acromegaly is almost always due to extra-pituitary GHRH secretion, mainly from neuroendocrine

  18. Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat

    PubMed Central

    Mangili, Alexandra; Falutz, Julian; Mamputu, Jean-Claude; Stepanians, Miganush; Hayward, Brooke

    2015-01-01

    Background Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy. Objectives 1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm2, a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin. Methods Data were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models. Results Metabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44). Conclusions Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin

  19. Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat.

    PubMed

    Mangili, Alexandra; Falutz, Julian; Mamputu, Jean-Claude; Stepanians, Miganush; Hayward, Brooke

    2015-01-01

    Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy. 1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm2, a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin. Data were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models. Metabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44). Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin-treated patients than that of patients receiving placebo.

  20. Leptin alters the response of the growth hormone releasing factor- growth hormone--insulin-like growth factor-I axis to fasting.

    PubMed

    LaPaglia, N; Steiner, J; Kirsteins, L; Emanuele, M; Emanuele, N

    1998-10-01

    Proper nutritional status is critical for maintaining growth and metabolic function, playing an intimate role in neuroendocrine regulation. Leptin, the recently identified product of the obese gene, may very well be an integral signal which regulates neuroendocrine responses in times of food deprivation. The present study examines leptin's ability to regulate hormonal synthesis and secretion within the GRF-GH-IGF axis in the adult male rat during almost 3 days of fasting. Serum levels of GH and IGF-I were drastically suppressed by fasting. Daily leptin administration was able to fully prevent the fasting-induced fall in serum GH. Leptin failed to restore IGF-I to control levels, however, suggesting possible GH resistance. Fasting caused an insignificant increase in GH mRNA, while leptin injections significantly increased steady-state levels of this message. The GRF receptor (GRFr) message was not altered with fasting or leptin treatment. Leptin also exhibited effects at the hypothalamic level. Fasting induced a sharp fall in GRF mRNA expression and leptin injections partially prevented this fall. However, there were no observed changes in the hypothalamic GRF content. These results provide evidence that leptin may function as a neuromodulator of the GRF-GH-IGF axis communicating to this hormonal system the nutritional status of the animal.

  1. Cloning and characterization of mouse growth hormone-releasing hormone (GRH) complementary DNA: increased GRH messenger RNA levels in the growth hormone-deficient lit/lit mouse.

    PubMed

    Frohman, M A; Downs, T R; Chomczynski, P; Frohman, L A

    1989-10-01

    We have isolated and cloned the full length cDNA for mouse GH-releasing hormone (mGRH) from mouse hypothalamus using a recently described strategy involving the polymerase chain reaction technique (PCR). Degenerate oligonucleotide primers were selected based on short (six amino acids) conserved regions in the human and rat GRH peptides that would recognize DNA sequences encoding similar amino acids regardless of codon usage. Primer-extended cDNA was amplified by PCR on cDNA templates prepared by reverse transcribing total mouse hypothalamic RNA. After cloning and sequencing the initial product, the 3' and 5' ends of mGRH were generated using a separate PCR strategy (RACE protocol). The mGRH cDNA encodes a 103-amino acid reading frame, structurally similar to the human and rat GRH genes, containing a signal sequence, a 42-residue GRH peptide, and a 31-residue C-terminal region. Although the structures of mouse and rat GRH are highly conserved in the signal peptide and C-terminal region, there is considerable diversity in the GRH region, which exhibits nearly comparable homology with the rat (68%) and human (62%) structures. Differences between mouse and rat GRH were also found in the amino acid cleavage sites at the 5' and 3' ends of the mature peptide and at the polyadenylation signal.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Is the growth outcome of children with idiopathic short stature and isolated growth hormone deficiency following treatment with growth hormone and a luteinizing hormone-releasing hormone agonist superior to that obtained by GH alone?

    PubMed

    Colmenares, Ana; González, Laura; Gunczler, Peter; Lanes, Roberto

    2012-01-01

    The aim of this study was to evaluate the effect of combined therapy with growth hormone (GH) and luteinizing hormone-releasing hormone agonist (LHRHa) on the near-final height (NFH) of children with idiopathic short stature (ISS) and growth hormone deficiency (GHD) in early puberty. A retrospective analysis of 20 patients with ISS and 9 patients with GHD treated with combined therapy was undertaken. Twelve children with ISS and ten with GHD, treated with GH alone, served as controls. Patients were matched at baseline for chronological age, bone age, height standard deviation score (SDS), and pubertal development. Patients with ISS or GHD treated with combined therapy improved both their predicted adult height (PAH) at 2 years of therapy (ISS, p < 0.001; GHD, p = 0.03) and their NFH (ISS, p < 0.05; GHD, p = 0.05). Treatment with combined therapy did not generate additional benefits on the PAH after 2 years of therapy (ISS children, an increase of 7.9 +/- 4.9 cm with combined therapy vs. 7.3 +/- 6.0 cm with GH; GHD children, an increase of 6.8 +/- 7.8 cm with combined therapy vs. 5 +/- 5.9 cm with GH). The total height gain SDS was higher in patients treated with GH alone compared with those with combined therapy, but the difference was not significant (ISS children, a gain of 2.4 SDS with GH vs. 0.8 SDS with combined therapy; GHD children, a gain of 1.8 SDS with GH vs. 0.6 SDS with combined therapy). Although 2 years of combined treatment with GH and LHRHa improved the PAH and the NFH of ISS and GHD patients in early puberty, this improvement was not significant compared with that observed in similar subjects treated with GH alone.

  3. Growth hormone-releasing hormone stimulates GH release while inhibiting ghrelin- and sGnRH-induced LH release from goldfish pituitary cells.

    PubMed

    Grey, Caleb L; Chang, John P

    2013-06-01

    Goldfish GH-releasing hormone (gGHRH) has been recently identified and shown to stimulate GH release in goldfish. In goldfish, neuroendocrine regulation of GH release is multifactorial and known stimulators include goldfish ghrelin (gGRLN19) and salmon gonadotropin-releasing hormone (sGnRH), factors that also enhance LH secretion. To further understand the complex regulation of pituitary hormone release in goldfish, we examined the interactions between gGHRH, gGRLN19, and sGnRH on GH and LH release from primary cultures of goldfish pituitary cells in perifusion. Treatment with 100nM gGHRH for 55min stimulated GH release. A 5-min pulse of either 1nM gGRLN19 or 100nM sGnRH induced GH release in naïve cells, and these were just as effective in cells receiving gGHRH. Interestingly, gGHRH abolished both gGRLN19- and sGnRH-induced LH release and reduced basal LH secretion levels. These results suggest that gGHRH does not interfere with sGnRH or gGRLN19 actions in the goldfish somatotropes and further reveal, for the first time, that GHRH may act as an inhibitor of stimulated and basal LH release by actions at the level of pituitary cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Growth hormone responses to growth hormone-releasing hormone and hexarelin in fed and fasted dogs: effect of somatostatin infusion or pretreatment with pirenzepine.

    PubMed

    Rigamonti, A E; Marazzi, N; Cella, S G; Cattaneo, L; Müller, E E

    1998-02-01

    Using unanesthetized young male and female beagle dogs, before and after a 2-day fast, we studied the effect of an i.v. infusion of 0.9% saline (5 ml/h), somatostatin (SS, 4 or 8 micrograms/kg/h), or pretreatment with pirenzepine (PZ, 0.6 mg/kg i.v.), a muscarinic cholinergic antagonist which allegedly releases SS, on the GH release evoked by acute administration of GHRH (2 micrograms/kg i.v.), hexarelin (HEXA), a member of the GH-releasing peptide family (250 micrograms/kg i.v.) or GHRH plus HEXA. In fasted dogs, GHRH delivered during saline infusion induced a clear-cut rise in plasma GH levels, significantly higher than that which it induced in fed dogs. In contrast, HEXA, although very effective in causing the release of GH, only slightly increased GH secretion in fasted dogs over that which it induced in fed dogs. Co-administration of GHRH plus HEXA into fed dogs induced a synergic GH response that further increased with fasting. The action of GHRH in fed dogs was abolished by the lower dose of SS, whereas SS at either dose was ineffective in suppressing the GH-releasing effect during fasting. Infusion of the lower dose of SS failed to counter the action of HEXA, either before or during fasting, whilst the higher SS dose partially reduced it in both conditions. In contrast to SS, PZ reduced the GH-releasing effect of GHRH and HEXA, both in the fed state and, though to a lesser extent, during fasting. Pirenzepine only slightly reduced the robust GH rise elicited by GHRH plus HEXA in fed dogs. The suppressive effect of PZ on the GH response to combined administration of the peptides was lowest in fasted dogs. These data show that: (1) fasting augmented the GH response to GHRH and (to a lesser degree) to HEXA; (2) SS inhibited the GH response to GHRH in the fed state, but not in the fasted state; (3) only the higher dose of SS partially reduced the GH stimulation by HEXA in either the fed or the fasted state; (4) PZ lowered the GH response to GHRH and to HEXA in

  5. Insulin-like growth factor I modulates hypothalamic somatostatin through a growth hormone releasing factor increased somatostatin release and messenger ribonucleic acid levels.

    PubMed

    Aguila, M C; Boggaram, V; McCann, S M

    1993-10-22

    Insulin-like growth factor I (IGF-I) has been shown to participate in feedback inhibition of growth hormone (GH) secretion at the level of both the pituitary and hypothalamus. Therefore, we tested the possible involvement of IGF-I on somatostatin (SRIF) and GH-releasing factor (GRF) release in median eminence (ME) fragments and periventricular nucleus (PeN) of male rats. The levels of SRIF messenger ribonucleic acid (mRNA) were also determined in PeN incubated in vitro with IGF-I. The ME's were incubated in Krebs-Ringer bicarbonate glucose buffer in the presence of various concentrations of IGF-I (10(-7) to 10(-11) M) for 30 min. SRIF and GRF released into the medium were quantitated by RIA. The release of SRIF and GRF from the ME's was stimulated significantly (P < 0.025 and P < 0.05, respectively) by 10(-9) M IGF-I. To determine whether the effect of IGF-I on SRIF release is mediated by GRF release in the ME, a specific GRF antibody (ab) (1:500) was used concomitantly with IGF-I (10(-9) M). The release of SRIF induced by IGF-I was blocked by the GRF ab (P < 0.001), but not by normal rabbit serum used at the same dilution. To determine the effect of IGF-I on the regulation of SRIF mRNA levels, SRIF mRNA was determined in PeN explants incubated in the presence of IGF-I (10(-8) to 10(-10) M) for 2 to 6 h. Levels of SRIF mRNA were determined by a S1 nuclease protection assay using a 32P-labelled rat SRIF riboprobe.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Inhibition of mammary tumor growth in rats and mice by administration of agonistic and antagonistic analogs of luteinizing hormone-releasing hormone.

    PubMed Central

    Redding, T W; Schally, A V

    1983-01-01

    Experiments were undertaken with estrogen-dependent mammary carcinomas in rats and mice to determine the antitumor activities of agonistic and antagonistic analogs of luteinizing hormone-releasing hormone (LH-RH). Chronic administration of the agonist [D-Trp6]LH-RH or of antagonist 1 ( [NAc-D-p-Cl-Phe1,2-Phe3,D-Arg6-D-Ala10]LH-RH) at doses of 25 and 50 micrograms/day, respectively, for 21 days to mice bearing the MXT mammary carcinoma significantly decreased tumor weight and volume. The weight of the ovaries and serum progesterone levels in mice treated with [D-Trp6]LH-RH or antagonist 1 were also significantly reduced. In rats bearing the MT/W9A mammary adenocarcinoma, chronic administration of [D-Trp6]LH-RH at a dose of 25 micrograms twice a day or of antagonist 2 ( [NAc-D-p-Cl-Phe1,2,D-Trp3,D-Arg6,D-Ala10]LH-RH) at a dose of 50 micrograms twice a day for 28 days significantly decreased tumor weight and volume. Chronic treatment with either [D-Trp6]LH-RH or antagonist 2 markedly diminished the weight of the ovaries and serum levels of both estrogen and progesterone. Serum luteinizing hormone was significantly decreased in rats treated with antagonist 2 but not in rats treated with [D-Trp6]LH-RH. There was a significant drop in serum prolactin levels in rats treated with [D-Trp6]LH-RH but not in those receiving antagonist 2. Regression of mammary tumors in rats and mice in response to chronic administration of [D-Trp6]LH-RH and the two antagonistic analogs of LH-RH suggests that these compounds should be considered for the development of a new hormone therapy for breast cancer in women. PMID:6219395

  7. Changes in serum growth hormone and prolactin levels, and in hypothalamic growth hormone-releasing hormone, thyrotropin-releasing hormone and somatostatin content, after superior cervical sympathectomy in rats.

    PubMed

    Cardinalí, D P; Esquifino, A I; Arce, A; Vara, E; Ariznavarreta, C; Tresguerres, J A

    1994-01-01

    After bilateral superior cervical ganglionectomy (SCGx) of adult male rats, norepinephrine (NE) content of the medial basal hypothalamus (MBH) decreased significantly by 39-47% from 16 h to 7 days after surgery. During this time the levels of serum growth hormone (GH) and prolactin (PRL) and of MBH GH-releasing hormone (GRH), thyrotropin-releasing hormone (TRH) and somatostatin were measured by RIA. In sham-operated controls, serum PRL increased and serum GH decreased 16-24 h after surgery, attaining pre-surgical levels later on. In SCGx rats, significantly lower serum GH and PRL and higher MBH GRH and TRH content as compared to controls was observed 16-24 h after surgery, during the wallerian degeneration phase after SCGx. MBH somatostatin concentration decreased in SCGx rats 20 h after surgery. Two injections of the alpha 1-adrenoceptor blocker prazosin 45 and 90 min before sacrifice, alone or together with the beta-blocker propranolol, prevented the changes in MBH hypophysiotropic hormone content, as well as in serum GH and PRL levels, found in SCGx rats 20 h after surgery. Propranolol treatment did not affect hormone levels. Neither drug modified the decrease in MBH NE content observed after SCGx. The results argue in favor of the existence of physiologically relevant projections from superior cervical ganglion neurons to the MBH controlling hypophysiotropic hormone release.

  8. Effects of hypothalamic dopamine on growth hormone-releasing hormone-induced growth hormone secretion and thyrotropin-releasing hormone-induced prolactin secretion in goats.

    PubMed

    Jin, Jin; Hashizume, Tsutomu

    2015-06-01

    The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on the secretion of growth hormone (GH) in goats. The GH-releasing response to an intravenous (i.v.) injection of GH-releasing hormone (GHRH, 0.25 μg/kg body weight (BW)) was examined after treatments to augment central DA using carbidopa (carbi, 1 mg/kg BW) and L-dopa (1 mg/kg BW) in male and female goats under a 16-h photoperiod (16 h light, 8 h dark) condition. GHRH significantly and rapidly stimulated the release of GH after its i.v. administration to goats (P < 0.05). The carbi and L-dopa treatments completely suppressed GH-releasing responses to GHRH in both male and female goats (P < 0.05). The prolactin (PRL)-releasing response to an i.v. injection of thyrotropin-releasing hormone (TRH, 1 μg/kg BW) was additionally examined in male goats in this study to confirm modifications to central DA concentrations. The treatments with carbi and L-dopa significantly reduced TRH-induced PRL release in goats (P < 0.05). These results demonstrated that hypothalamic DA was involved in the regulatory mechanisms of GH, as well as PRL secretion in goats.

  9. Improved response of growth hormone to growth hormone-releasing hormone and reversible chronic thyroiditis after hydrocortisone replacement in isolated adrenocorticotropic hormone deficiency.

    PubMed

    Inagaki, Miho; Sato, Haruhiro; Miyamoto, Yoshiyasu; Hirukawa, Takashi; Sawaya, Asako; Miyakogawa, Takayo; Tatsumi, Ryoko; Kakuta, Takatoshi

    2009-07-20

    We report a 44-year-old Japanese man who showed a reversible blunted response of growth hormone (GH) to GH-releasing hormone (GRH) stimulation test and reversible chronic thyroiditis accompanied by isolated ACTH deficiency. He was admitted to our hospital because of severe general malaise, hypotension, and hypoglycemia. He showed repeated attacks of hypoglycemia, and his serum sodium level gradually decreased. Finally, he was referred to the endocrinology division, where his adrenocorticotropic hormone (ACTH) and cortisol values were found to be low, and his GH level was slightly elevated. An increased value of thyroid stimulating hormone (TSH) and decreased values of free triidothyronine and free thyroxine were observed along with anti-thyroglobulin antibody, suggesting chronic thyroiditis. Pituitary stimulation tests revealed a blunted response of ACTH and cortisol to corticotropin-releasing hormone, and a blunted response of GH to GRH. Hydrocortisone replacement was then started, and this improved the patient's general condition. His hypothyroid state gradually ameliorated and his titer of anti-thyroglobulin antibody decreased to the normal range. Pituitary function was re-evaluated with GRH stimulation test under a maintenance dose of 20 mg/day hydrocortisone and showed a normal response of GH to GRH. It is suggested that re-evaluation of pituitary and thyroid function is useful for diagnosing isolated ACTH deficiency after starting a maintenance dose of hydrocortisone in order to avoid unnecessary replacement of thyroid hormone.

  10. Dihydropyridine-sensitive calcium channel activity related to prolactin, growth hormone, and luteinizing hormone release from anterior pituitary cells in culture: interactions with somatostatin, dopamine, and estrogens

    SciTech Connect

    Drouva, S.V.; Rerat, E.; Bihoreau, C.; Laplante, E.; Rasolonjanahary, R.; Clauser, H.; Kordon, C.

    1988-12-01

    In the present work, we determined the activity of voltage-dependent dihydropyridine (DHP)-sensitive Ca2+ channels related to PRL, GH, and LH secretion in primary cultures of pituitary cells from male or female rats. We investigated their modulation by 17 beta-estradiol (E2) and their involvement in dopamine (DA) and somatostatin (SRIF) inhibition of PRL and GH release. BAY-K-8644 (BAYK), a DHP agonist which increases the opening time of already activated channels, stimulated PRL and GH secretion in a dose-dependent manner. The effect was more pronounced on PRL than on GH release. BAYK-evoked hormone secretion was further amplified by simultaneous application of K+ (30 or 56 mM) to the cell cultures; in parallel, BAYK-induced 45Ca uptake by the cells was potentiated in the presence of depolarizing stimuli. In contrast, BAYK was unable to stimulate LH secretion from male pituitary cells, but it potentiated LHRH- as well as K+-induced LH release; it had only a weak effect on LH secretion from female cell cultures. Basal and BAYK-induced pituitary hormone release were blocked by the Ca2+ channel antagonist nitrendipine. Under no condition did BAYK affect the hydrolysis of phosphoinositides or cAMP formation. Pretreatment of female pituitary cell cultures with E2 (10(-9) M) for 72 h enhanced LH and PRL responses to BAYK, but was ineffective on GH secretion. DA (10(-7) M) inhibited basal and BAYK-induced PRL release from male or female pituitary cells treated or not treated with E2 (10(-9) M). SRIF (10(-9) and 10(-8) M) reversed BAYK-evoked GH release to the same extent in cell cultures derived from male or female animals. It was ineffective on BAYK-induced PRL secretion in the absence of E2, but antagonized it after E2 pretreatment. The effect was dependent upon the time of steroid treatment and was specific, since 17 alpha-estradiol was inactive.

  11. Uptake and ultrastructural localization of a (125I) growth hormone releasing factor agonist in male rat pituitary gland: Evidence for internalization

    SciTech Connect

    Morel, G. )

    1991-09-01

    GRF was isolated from a human tumor of the pancreas and characterized. GRF stimulates the in vivo and in vitro secretion of GH. The present study was designed to find out whether human (h) GRF agonist could be internalized and to determine the subcellular localization of internalized peptide in somatotrophs. Autoradiography was performed on rat anterior pituitary glands removed at specific time intervals (2-60 min) after iv injection of monoradioiodinated (125I) (His1,Nle27) hGRF (1-32) NH2. Administration of an excess of unlabeled hGRF agonist along with the radioiodinated hormone prevented the uptake, indicating the specificity of the reaction. At the ultrastructural level only the somatotrophs appeared to contain silver grains. The main effect of hGRF agonist injection on the cytological aspect of the somatotrophs was a decrease in the area occupied by secretory granules, accompanied inversely, by an increase in that of the Golgi complex. The time course study in somatotrophs showed that five compartments (plasma membrane, secretory granules, cytoplasmic matrix, nuclear membrane, and lysosomes) have distinct marked labeling patterns. Plasma membrane, secretory granules, and nuclear membrane were labeled throughout the time course studied (2-60 min after injection). Cytoplasmic matrix was labeled 5 min post injection and lysosomes 15 and 30 min after injection. The Golgi complex, mitochondria, rough endoplasmic reticulum, and nucleus matrix were not labeled. The findings show the cellular specificity of GRF uptake by somatotrophs and the internalization process from the plasma membrane to the intracellular organelles (secretory granules, lysosomes, and nuclear membrane). Labeling of the secretory granule compartment suggests that granules may bind and protect internalized peptide from lysosomal degradation.

  12. Inhibition of growth of OV-1063 human epithelial ovarian cancer xenografts in nude mice by treatment with luteinizing hormone-releasing hormone antagonist SB-75.

    PubMed Central

    Yano, T; Pinski, J; Halmos, G; Szepeshazi, K; Groot, K; Schally, A V

    1994-01-01

    Female athymic nude mice bearing xenografts of OV-1063 human epithelial ovarian cancer cell line were treated with potent luteinizing hormone (LH)-releasing hormone (LH-RH) antagonist SB-75 (Cetrorelix; [Ac-D-Nal(2)1, D-Phe(4 CI)2, D-Pal(3)3, D-Cit6, D-Ala10]LH-RH in which Ac-D-Nal(2) = N-acetyl-3-(2-naphthyl)-D-alanine, D-Phe(4CI) = 4-chloro-D-phenylalanine, D-Pal(3) = 3-(3-pyridyl)-D-alanine, and D-Cit = D-Citrulline) or with the agonist [D-Trp6]LH-RH. In the first experiment, SB-75 and [D-Trp6]LH-RH were administered in the form of microcapsules releasing 60 and 25 micrograms/day, respectively. In the second study, the analogs were given by daily s.c. injections in doses of 100 micrograms/day. In both experiments, tumor growth, as measured by reduction in tumor volume, percentage change in tumor volume, tumor burden, and increase in tumor doubling time, was significantly inhibited by treatment with SB-75 but not with [D-Trp6]LH-RH. Uterine and ovarian weights were reduced and serum LH levels decreased by administration of either analog. Chronic treatment with SB-75 greatly reduced the concentration of receptors for epidermal growth factor and insulin-like growth factor I in tumor cell membranes, a phenomenon that might be related to tumor growth inhibition. It is possible that the antitumoral effects of SB-75 on OV-1063 ovarian cancers are exerted not only through the suppression of the pituitary-gonadal axis, but also directly. In view of its strong inhibitory effect on the growth of OV-1063 ovarian cancers in vivo, the potent LH-RH antagonist SB-75 might be considered for possible hormonal therapy of advanced epithelial ovarian carcinoma. PMID:7518926

  13. Inhibition of proliferation, VEGF secretion of human neuroendocrine tumor cell line NCI-H727 by an antagonist of growth hormone-releasing hormone (GH-RH) in vitro.

    PubMed

    Sacewicz, Małgorzata; Lawnicka, Hanna; Siejka, Agnieszka; Stepień, Tomasz; Krupiński, Roman; Komorowski, Jan; Stepień, Henryk

    2008-09-08

    Growth hormone-releasing hormone (GH-RH) can stimulate not only growth hormone (GH) secretion by anterior pituitary gland but also proliferation of many cancer cell lines in vitro and in xenografts tumor models in vivo. Several antagonists of GH-RH have been shown to inhibit several cancer growths, but the role of GH-RH antagonists in the regulation of neuroendocrine cancers cell proliferation and tumor progression remains obscure. The aim of the study was to evaluate the influence of JV-1-36 (synthetic GH-RH antagonist) on proliferation and VEGF secretion by human neuroendocrine lung non-small cell carcinoma (NCI-H727) using cell culture model. The in vitro effect of JV-1-36 on the proliferation of NCI-H727 cells was assessed by the measurement of BrdU incorporation by colorimetric immunoassay. The presence of VEGF and membrane GH-RH receptors on the surface of H727 cells were visualized by immunocytochemistry using specific anti-GH-RH receptor antibody directed to the carboxy-terminal region. VEGF secretion to the cell cultures supernatants was assessed by ELISA methods. Immunoreactive cell membrane GH-RH receptors and VEGF-immunopositive cytoplasmatic granules were clearly confined on the surface of nearly all cancer cells. JV-1-36 at the concentration of 10(-6)-10(-10)M significantly inhibited growth of H727 cells, compared with untreated controls. In H727 cells, the antiproliferative JV-1-36 effect was associated with a dose-dependent reduction of VEGF secretion. In conclusion, our findings demonstrate the strong evidence for the antiproliferative action of GH-RH antagonist JV-1-36 for the NCI-H727 cells. In addition the suppression of VEGF secretion by H727 cells might contribute, at least in part, to the antitumor action of GH-RH antagonists.

  14. Effect of long-term infusion with recombinant growth hormone-releasing factor and recombinant bovine somatotropin on development and function of dominant follicles and corpora lutea in Holstein cows.

    PubMed

    Jimenez-Krassel, F; Binelli, M; Tucker, H A; Ireland, J J

    1999-09-01

    The objective of this study was to evaluate the effects of recombinant bovine growth hormone-releasing factor (rGRF) or recombinant bovine somatotropin (rbST) on growth and function of the first-wave dominant follicle and corpus luteum. Primiparous Holstein cows (117 d postpartum) were infused with 12 mg/d of rGRF (n = 10) or 29 mg/d of rbST (n = 10) for 63 d, and non-infused cows (n = 10) were controls. At slaughter on d 5 of an estrous cycle, blood and ovaries were collected and data from cows with a corpus luteum were analyzed (control, n = 8; rGRF, n = 5; rbST, n = 6). Treatment with rGRF or rbST increased somatotropin (ST) and IGF-I in serum similarly compared with controls. In contrast, rbST-treated cows had higher concentrations of ST in follicular fluid (FF) compared with rGRF-treated and control cows. In addition, rbST, but not rGRF, increased the number and decreased the size of estrogen-active follicles (EA; estradiol > progesterone concentrations in FF), increased the abundance of IGF binding proteins-2, -3, and -4 in FF from EA follicles, and increased the number but decreased the size of corpora lutea and decreased concentration of progesterone in serum compared with controls. Based on these results, we concluded that long-term infusion of rbST alters growth and function of the first-wave dominant follicle and the corpus luteum in cattle.

  15. Overexpression of the growth-hormone-releasing hormone gene in acromegaly-associated pituitary tumors. An event associated with neoplastic progression and aggressive behavior.

    PubMed Central

    Thapar, K.; Kovacs, K.; Stefaneanu, L.; Scheithauer, B.; Killinger, D. W.; Lioyd, R. V.; Smyth, H. S.; Barr, A.; Thorner, M. O.; Gaylinn, B.; Laws, E. R.

    1997-01-01

    The clinical behavior of growth hormone (GH)-producing pituitary tumors is known to vary greatly; however, the events underlying this variability remain poorly understood. Herein we demonstrate that tumor overexpression of the GH-releasing hormone (GHRH) gene is one prognostically informative event associated with the clinical aggressiveness of somatotroph pituitary tumors. Accumulation of GHRH mRNA transcripts was demonstrated in 91 of a consecutive series of 100 somatotroph tumors by in situ hybridization; these findings were corroborated by Northern analysis and reverse transcriptase polymerase chain reaction, and protein translation was confirmed by Western blotting. By comparison, transcript accumulation was absent or negligibly low in 30 normal pituitary glands. GHRH transcripts were found to preferentially accumulate among clinically aggressive tumors. Specifically, GHRH mRNA signal intensity was 1) linearly correlated with Ki-67 tumor growth fractions (r = 0.71; P < 0.001), 2) linearly correlated with preoperative serum GH levels (r = 0.56; p = 0.01), 3) higher among invasive tumors (P < 0.001), and 4) highest in those tumors in which post-operative remission was not achieved (P < 0.001). Using multivariate logistic regression, a model of postoperative remission likelihood was derived wherein remission was defined by the single criterion of suppressibility of GH levels to less than 2 ng/ml during an oral glucose tolerance test. In this outcome model, GHRH mRNA signal intensity proved to be the most important explanatory variable overall, eclipsing any and all conventional clinicopathological predictors as the single most significant predictor of postoperative remission; increases in GHRH mRNA signal were associated with marked declines in remission likelihood. The generalizability of this outcome model was further validated by the model's significant performance in predicting postoperative remission in a random sample of 30 somatotroph tumors treated at

  16. Effect of Oral Glucose Administration on Rebound Growth Hormone Release in Normal and Obese Women: The Role of Adiposity, Insulin Sensitivity and Ghrelin

    PubMed Central

    Pena-Bello, Lara; Pertega-Diaz, Sonia; Outeiriño-Blanco, Elena; Garcia-Buela, Jesus; Tovar, Sulay; Sangiao-Alvarellos, Susana; Dieguez, Carlos; Cordido, Fernando

    2015-01-01

    Context Metabolic substrates and nutritional status play a major role in growth hormone (GH) secretion. Uncovering the mechanisms involved in GH secretion following oral glucose (OG) administration in normal and obese patients is a pending issue. Objective The aim of this study was to investigate GH after OG in relation with adiposity, insulin secretion and action, and ghrelin secretion in obese and healthy women, to further elucidate the mechanism of GH secretion after OG and the altered GH secretion in obesity. Participants and Methods We included 64 healthy and obese women. After an overnight fast, 75 g of OG were administered; GH, glucose, insulin and ghrelin were obtained during 300 minutes. Insulin secretion and action indices and the area under the curve (AUC) were calculated for GH, glucose, insulin and ghrelin. Univariate and multivariate linear regression analyses were employed. Results The AUC of GH (μg/L•min) was lower in obese (249.8±41.8) than in healthy women (490.4±74.6), P=0.001. The AUC of total ghrelin (pg/mL•min) was lower in obese (240995.5±11094.2) than in healthy women (340797.5±37757.5), P=0.042. There were significant correlations between GH secretion and the different adiposity, insulin secretion and action, and ghrelin secretion indices. After multivariate analysis only ghrelin AUC remained a significant predictor for fasting and peak GH. PMID:25782001

  17. Effect of oral glucose administration on rebound growth hormone release in normal and obese women: the role of adiposity, insulin sensitivity and ghrelin.

    PubMed

    Pena-Bello, Lara; Pertega-Diaz, Sonia; Outeiriño-Blanco, Elena; Garcia-Buela, Jesus; Tovar, Sulay; Sangiao-Alvarellos, Susana; Dieguez, Carlos; Cordido, Fernando

    2015-01-01

    Metabolic substrates and nutritional status play a major role in growth hormone (GH) secretion. Uncovering the mechanisms involved in GH secretion following oral glucose (OG) administration in normal and obese patients is a pending issue. The aim of this study was to investigate GH after OG in relation with adiposity, insulin secretion and action, and ghrelin secretion in obese and healthy women, to further elucidate the mechanism of GH secretion after OG and the altered GH secretion in obesity. We included 64 healthy and obese women. After an overnight fast, 75 g of OG were administered; GH, glucose, insulin and ghrelin were obtained during 300 minutes. Insulin secretion and action indices and the area under the curve (AUC) were calculated for GH, glucose, insulin and ghrelin. Univariate and multivariate linear regression analyses were employed. The AUC of GH (μg/L•min) was lower in obese (249.8±41.8) than in healthy women (490.4±74.6), P=0.001. The AUC of total ghrelin (pg/mL•min) was lower in obese (240995.5±11094.2) than in healthy women (340797.5±37757.5), P=0.042. There were significant correlations between GH secretion and the different adiposity, insulin secretion and action, and ghrelin secretion indices. After multivariate analysis only ghrelin AUC remained a significant predictor for fasting and peak GH.

  18. In vitro effects of thyrotropin-releasing hormone and somatostatin on prolactin and growth hormone release by the pituitary of Poecilia latipinna. I. An electrophoretic study.

    PubMed

    Wigham, T; Batten, T F

    1984-09-01

    Pituitary glands were removed from Poecilia latipinna which had been maintained in one-third seawater and were incubated for 18 hr in media of either 300 mosmol/kg (OP300) or 340 mosmol/kg (OP340) osmotic pressure for measurement of both total and newly synthesised prolactin (PRL) and growth hormone (GH) release. Thyrotropin-releasing hormone (TRH) at 100 ng/ml increased release of total and newly synthesised PRL into OP340, but not into OP300, medium. Conversely, 300 ng/ml of somatotropin-release-inhibiting factor (SRIF) inhibited total and newly synthesised PRL release into OP300, but not OP340, medium. At 1000 ng/ml, SRIF inhibited total PRL release into both media, but newly synthesised PRL release was reduced significantly only in OP300 medium. The release of GH was unaffected by 100 ng/ml TRH in OP300 medium, but both total and newly synthesised GH release were enhanced by this dose in OP340 medium. SRIF at 300 ng/ml reduced total GH release into OP300 medium, whereas the release of newly synthesised GH was inhibited in OP340 medium. At 1000 ng/ml, SRIF inhibited total GH release into both media, but release of the newly synthesised hormone was not significantly altered. These results suggest that TRH can stimulate and SRIF inhibit both PRL and GH release by Poecilia pituitaries, but that these effects may be modulated by plasma osmotic pressure.

  19. Kisspeptin Stimulates Growth Hormone Release by Utilizing Neuropeptide Y Pathways and Is Dependent on the Presence of Ghrelin in the Ewe.

    PubMed

    Foradori, Chad D; Whitlock, Brian K; Daniel, Jay A; Zimmerman, Arthur D; Jones, Melaney A; Read, Casey C; Steele, Barbara P; Smith, Jeremy T; Clarke, Iain J; Elsasser, Theodore H; Keisler, Duane H; Sartin, James L

    2017-10-01

    Although kisspeptin is the primary stimulator of gonadotropin-releasing hormone secretion and therefore the hypothalamic-pituitary-gonadal axis, recent findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Here we show that central delivery of kisspeptin causes a robust rise in plasma GH in fasted but not fed sheep. Kisspeptin-induced GH secretion was similar in animals fasted for 24 hours and those fasted for 72 hours, suggesting that the factors involved in kisspeptin-induced GH secretion are responsive to loss of food availability and not the result of severe negative energy balance. Pretreatment with the neuropeptide Y (NPY) Y1 receptor antagonist, BIBO 3304, blocked the effects of kisspeptin-induced GH release, implicating NPY as an intermediary. Kisspeptin treatment induced c-Fos in NPY and GH-releasing hormone (GHRH) cells of the arcuate nucleus. The same kisspeptin treatment resulted in a reduction in c-Fos in somatostatin (SS) cells in the periventricular nucleus. Finally, blockade of systemic ghrelin release or antagonism of the ghrelin receptor eliminated or reduced the ability of kisspeptin to induce GH release, suggesting the presence of ghrelin is required for kisspeptin-induced GH release in fasted animals. Our findings support the hypothesis that during short-term fasting, systemic ghrelin concentrations and NPY expression in the arcuate nucleus rise. This permits kisspeptin activation of NPY cells. In turn, NPY stimulates GHRH cells and inhibits SS cells, resulting in GH release. We propose a mechanism by which kisspeptin conveys reproductive and hormone status onto the somatotropic axis, resulting in alterations in GH release. Copyright © 2017 Endocrine Society.

  20. Differential sensitivity of growth hormone-releasing hormone and somatostatin release from perifused mouse hypothalamic fragments in response to glucose deficiency.

    PubMed

    Sato, M; Frohman, L A

    1993-06-01

    The effects of glucose deficiency on growth hormone (GH)-releasing hormone (GRH) and somatostatin (SRIH) release from mouse hypothalamic fragments were investigated using an in vitro perifusion system. Fragments were perifused with Krebs-Ringer bicarbonate solution (KRB) containing 5.6 mM glucose for 3 h followed by reduced glucose concentrations in KRB for the next 2 h. GRH release was simulated by 0.7-2.8 mM glucose in an inverse concentration-dependent manner. In contrast, SRIH release was not stimulated by glucose at concentrations of 2.8 and 1.4 mM; only at 0.7 mM was there a modest stimulation of SRIH release that was comparable to the effect of 2.8 mM glucose on GRH release. The maximal stimulation of GRH and SRIH release by 0.7 mM glucose was 221 and 150%, respectively, of controls. Glucose concentrations of 11.2 and 22.4 mM inhibited GRH release but did not alter SRIH release. The glucose analog 2-deoxy-D-glucose (2-DG; 5.6-39.2 mM) also stimulated GRH release in a dose-dependent manner, and SRIH release was less sensitive to 2-DG than was GRH. The maximal stimulation of GRH and SRIH release by 39.2 mM 2-DG was 190 and 147%, respectively, of controls. Increases in GRH and SRIH release stimulated by 30 mM KCl 1 h after exposure to low glucose or 2-DG were not significantly different from those after exposure to 5.6 mM glucose. However, the SRIH response to K(+)-induced depolarization was much greater than that of GRH. The glucose intermediate pyruvate (4.9 and 9.8 mM) partially inhibited both GRH and SRIH release induced by 0.7 mM glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. β-Hydroxybutyric acid inhibits growth hormone-releasing hormone synthesis and secretion through the GPR109A/extracellular signal-regulated 1/2 signalling pathway in the hypothalamus.

    PubMed

    Fu, S-P; Liu, B-R; Wang, J-F; Xue, W-J; Liu, H-M; Zeng, Y-L; Huang, B-X; Li, S-N; Lv, Q-K; Wang, W; Liu, J-X

    2015-03-01

    β-Hydroxybutyric acid (BHBA) has recently been shown to regulate hormone synthesis and secretion in the hypothalamus. However, little is known about the effects of BHBA-mediated hormone regulation or the detailed mechanisms by which BHBA regulates growth hormone-releasing hormone (GHRH) synthesis and secretion. In the present study, we examined the expression of the BHBA receptor GPR109A in primary hypothalamic cell cultures. We hypothesised that BHBA regulates GHRH via GPR109A and its downstream signals. Initial in vivo studies conducted in rats demonstrated that GHRH mRNA expression in the hypothalamus was strongly inversely correlated with BHBA levels in the cerebrospinal fluid during postnatal development (r = -0.89, P < 0.01). Furthermore, i.c.v. administration of BHBA acutely decreased GHRH mRNA expression in rats. Further in vitro studies revealed a decrease in GHRH synthesis and secretion in primary hypothalamic cells after treatment with BHBA; this effect was inhibited when hypothalamic cells were pretreated with pertussis toxin (PTX). BHBA had no effect on GHRH synthesis and secretion in GT1-7 cells, which do not exhibit cell surface expression of GPR109A. Furthermore, BHBA acutely decreased the transcription of the homeobox gene for Gsh-1 in the hypothalamus in both in vivo and in vitro, and this effect was also inhibited by PTX in vitro. In primary hypothalamic cells, BHBA activated the extracellular signal-regulated kinase (ERK)1/2, p38 and c-Jun N-terminal kinase mitogen-activated protein kinase (MAPK) kinases, as shown by western blot analysis. Moreover, inhibition of ERK1/2 with U0126 attenuated the BHBA-mediated reduction in Gsh-1 expression and GHRH synthesis and secretion. These results strongly suggest that BHBA directly regulates GHRH synthesis and secretion via the GPR109A/ERK1/2 MAPK pathway, and also that Gsh-1 is essential for this function. © 2015 British Society for Neuroendocrinology.

  2. Simultaneous expression of growth hormone releasing hormone (GHRH) and hepatitis B surface antigen/somatostatin (HBsAg/SS) fusion genes in a construct in the skeletal muscle enhances rabbit weight gain.

    PubMed

    Dai, Jian-wei; Liu, Song-cai; Hao, Lin-lin; Zhang, Yong-liang; Zhang, Qianqian; Ren, Xiao-hui; Jiang, Qing-yan

    2008-01-01

    Somatostatin (SS) and growth hormone-releasing hormone (GHRH) are synthesized and secreted by the hypothalamus, which can control the synthesis and secretion of the growth hormone (GH) from the hypophysis as well as regulate the GH concentrations in animals and humans. In this article, we describe the regulation of animal growth using plasmid DNA encoding both the GHRH gene and the SS gene fused with the hepatitis B surface antigen (HBsAg) gene. We constructed a series of expression plasmids to express the GHRH and HBsAg-SS fusion genes individually as well as collectively. The fusion gene and GHRH were successfully expressed in Chinese hamster ovary (CHO) cells, as proven by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoblotting tests. Poly D, L-lactide-co-glycolic acid (PLGA) plasmid-encapsulating microspheres were prepared and injected intramuscularly into the leg skeletal muscles of rabbits. Weight gain/day and the levels of insulinlike growth factor-I (IGF-I), SS, and hepatitis B surface antibody (HBsAb) were monitored. During days 30 postinjection, increase in weight gain/day and IGF- I concentration and decrease in SS were observed in treatment groups. From days 15 to 30 postinjection, the weight gain/day significantly increased (P < 0.05) by 129.13%, 106.8%, and 72.82% relative to the control group in the co-expression GHRH and fusion gene (named P-G-HS), fusion gene (named P-HS), and GHRH (named P-G) groups, respectively. And most importantly, the P-G-HS group showed significant weight gain/day (P < 0.05) relative to the P-G and P-HS groups. A significant increase in the IGF-I concentration and decrease in the SS level relative to the control group were also observed. The results indicated that the combination of plasmid-mediated GHRH supplementation and positive immunization against SS led to more robust weight gain/day in rabbits.

  3. Fusion pores and their control of neurotransmitter and hormone release

    PubMed Central

    Chang, Che-Wei; Chiang, Chung-Wei

    2017-01-01

    Ca2+-triggered exocytosis functions broadly in the secretion of chemical signals, enabling neurons to release neurotransmitters and endocrine cells to release hormones. The biological demands on this process can vary enormously. Although synapses often release neurotransmitter in a small fraction of a millisecond, hormone release can be orders of magnitude slower. Vesicles usually contain multiple signaling molecules that can be released selectively and conditionally. Cells are able to control the speed, concentration profile, and content selectivity of release by tuning and tailoring exocytosis to meet different biological demands. Much of this regulation depends on the fusion pore—the aqueous pathway by which molecules leave a vesicle and move out into the surrounding extracellular space. Studies of fusion pores have illuminated how cells regulate secretion. Furthermore, the formation and growth of fusion pores serve as a readout for the progress of exocytosis, thus revealing key kinetic stages that provide clues about the underlying mechanisms. Herein, we review the structure, composition, and dynamics of fusion pores and discuss the implications for molecular mechanisms as well as for the cellular regulation of neurotransmitter and hormone release. PMID:28167663

  4. The purification of luteinizing-hormone-releasing factor with some observations on its properties

    PubMed Central

    Fawcett, C. P.; Reed, May; Charlton, H. M.; Harris, G. W.

    1968-01-01

    Bullock median-eminence tissue was used as a source of luteinizing-hormone-releasing factor for small-scale experiments to explore methods for its isolation. The presence of luteinizing-hormone-releasing factor was detected by the ovulation response in rabbits after intrapituitary infusion of the extract. Gel filtration was found to be suitable for the purification of these extracts. The releasing factor appeared to be a basic peptide of molecular weight in the range 1200–2500. On a larger scale, an extract of hypothalamic tissue from sheep was used to establish a multi-stage isolation procedure that resulted in a 200000-fold purification of luteinizing-hormone-releasing factor. After the initial extraction the isolation process consisted of: (1) two cycles of gel filtration; (2) anion-exchange chromatography; (3) gel filtration in a partially organic medium; (4) thin-layer chromatography on cellulose. Stage (3) separated two zones of activity each containing peptides. One of these was purified further by stage (4) to give a preparation that was active at a dose of 6μg. of peptide/animal, although activity diminished seriously during storage. This preparation contained only five or six components, but the small amounts of peptides obtained at this stage of purity were insufficient for full characterization. ImagesFig. 5. PMID:4889362

  5. Development and validation of a short-term, serum-free culture system for bovine granulosa cells: evaluation of the effects of somatotropin and growth hormone-releasing factor on estradiol production.

    PubMed

    Jimenez-Krassel, F; Ireland, J J

    2002-01-01

    The objective of this study was to develop and validate a short-term, serum-free culture system to determine whether recombinant bovine somatotropin (rbST) or recombinant bovine growth hormone-releasing factor (rbGRF) altered the estradiol-producing capacity of bovine granulosa cells isolated from dominant or subordinate follicles of the first follicular wave. Thus, ovaries were obtained at an abattoir from cows that were between d 2 to 5 or 6 to 10 of the estrous cycle. Three size classes of follicles were isolated from each cow's ovaries: small (2 to 5 mm in diameter), medium (6 to 14 mm), or the largest (6 to 19 mm). In vivo steroid-producing capacity of follicles was assessed by measuring concentration of estradiol, progesterone, androstenedione and 5alpha-dihydrotestosterone in each follicle. In vitro steroid-producing capacity was assessed by culturing granulosa cells from the different follicle sizes for 48 h in serum-free media with 19-OH androstenedione and measuring the estradiol and progesterone concentrations in media at the end of culture. The effect of different doses of FSH, rbST, or rbGRF on estradiol and progesterone production by granulosa cells from each follicle size class during d 2 to 5 or 6 to 10 was also evaluated. A high percentage (91.7%) of the largest follicles obtained on d 2 to 5 was estrogen-active (estradiol > progesterone) compared with other follicle classifications (d 2 to 5, small = 0%, medium = 13.8%; d 6 to 10, small = 0%, medium = 3.3%, largest = 33.3%). Estradiol was highest (P < 0.05) in the largest follicle on d 2 to 5 and correlated positively with follicle diameter. The pattern of in vitro production of estradiol by granulosa cells from the different follicle size classes reflected the original in vivo capacity of follicles to produce estradiol. However, only granulosa cells from the largest estrogen-active follicle on d 2 to 5 produced more estradiol than progesterone in vitro. Progesterone production by granulosa cells

  6. Effects of spaceflight on hypothalamic peptide systems controlling pituitary growth hormone dynamics

    NASA Technical Reports Server (NTRS)

    Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

    1992-01-01

    Possible effects of reduced gravity on central hypophysiotropic systems controlling growth hormone (GH) secretion were investigated in rats flown on Cosmos 1887 and 2044 biosatellites. Immunohistochemical (IHC)staining for the growth hormone-releasing factor (GRF), somatostatin (SS), and other hypothalamic hormones was performed on hypothalami obtained from rats. IHC analysis was complemented by quantitative in situ assessments of mRNAs encoding the precursors for these hormones. Data obtained suggest that exposure to microgravity causes a preferential reduction in GRF peptide and mRNA levels in hypophysiotropic neurons, which may contribute to impared GH secretion in animals subjected to spaceflight. Effects of weightlessness are not mimicked by hindlimb suspension in this system.

  7. Effects of spaceflight on hypothalamic peptide systems controlling pituitary growth hormone dynamics

    NASA Technical Reports Server (NTRS)

    Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

    1992-01-01

    Possible effects of reduced gravity on central hypophysiotropic systems controlling growth hormone (GH) secretion were investigated in rats flown on Cosmos 1887 and 2044 biosatellites. Immunohistochemical (IHC)staining for the growth hormone-releasing factor (GRF), somatostatin (SS), and other hypothalamic hormones was performed on hypothalami obtained from rats. IHC analysis was complemented by quantitative in situ assessments of mRNAs encoding the precursors for these hormones. Data obtained suggest that exposure to microgravity causes a preferential reduction in GRF peptide and mRNA levels in hypophysiotropic neurons, which may contribute to impared GH secretion in animals subjected to spaceflight. Effects of weightlessness are not mimicked by hindlimb suspension in this system.

  8. Different effects of growth hormone-releasing hormone (GRH) and somatostatin on growth hormone and stable metabolite of prostaglandin E2, 13, 14-dihydro-15-keto-prostaglandin E2 (PGE2-M) in normal subjects.

    PubMed

    Zacharieva, S; Muchá, I; Popova, J; Andonova, K

    1992-01-01

    Twenty four healthy subjects were placed in two treatment groups: 1. The first group consisted of twelve subjects in whom growth releasing hormone (GRH) (1 microgram/kg.BW) resulted in a marked and sustained elevation of serum growth hormone (GH) and a slight and delayed increase in plasma prostaglandin E2-M. In the second group, consisting also of twelve subjects, somatostatin infusion (500 micrograms/250 ml) was initiated and maintained for 60 min. Serum GH significantly decreased at 30 and 60 min during infusion and 15 min thereafter. We did not observe any changes in plasma prostaglandin E2-M during or after somatostatin infusion. The results obtained confirm previous in vitro studies and suggest a possible link between growth releasing hormone and prostaglandin E2 in their action on growth hormone secretion. It seems that somatostatin does not play a role in the control of prostaglandin E2 release.

  9. Gut hormone release after intestinal resection.

    PubMed Central

    Besterman, H S; Adrian, T E; Mallinson, C N; Christofides, N D; Sarson, D L; Pera, A; Lombardo, L; Modigliani, R; Bloom, S R

    1982-01-01

    To investigate the possible role of gut and pancreatic hormones in the adaptive responses to gut resection, plasma concentrations of the circulating hormones were measured, in response to a test breakfast, in patients with either small or large intestinal resection and in healthy control subjects. In 18 patients with partial ileal resection a significant threefold rise was found in basal and postprandial levels of pancreatic polypeptide, a fourfold increase in motilin, and more than a twofold increase in gastrin and enteroglucagon levels compared with healthy controls. In contrast, nine patients with colonic resection had a threefold rise in levels of pancreatic polypeptide only. One or more of these peptides may have a role in stimulating the adaptive changes found after gut resection. PMID:7117905

  10. Peptide growth factors, part A

    SciTech Connect

    Barnes, D.; Sirbasku, D.A.

    1987-01-01

    This book contains information on the following topics: Epidermal Growth Factor;Transforming Growth Factors;Bone and Cartilage Growth Factors;Somatomedin/Insulin-Like Growth Factors;Techniques for the Study of Growth Factor Activity;Assays, Phosphorylation, and Surface Membrane Effects.

  11. Inhibitory pathways and the inhibition of luteinizing hormone-releasing hormone release by alcohol

    PubMed Central

    Lomniczi, Alejandro; Mastronardi, Claudio A.; Faletti, Alicia G.; Seilicovich, Adriana; De Laurentiis, Andrea; McCann, Samuel M.; Rettori, Valeria

    2000-01-01

    In this research we examined the mechanisms by which ethanol (EtOH) inhibits luteinizing hormone-releasing hormone (LHRH) release from incubated medial basal hypothalamic explants. EtOH (100 mM) stimulated the release of two inhibitory neurotransmitters: γ-aminobutyric acid (GABA) and β-endorphin. EtOH also inhibited NO production, indicative of a suppression of nitric oxide synthase (NOS) activity. This inhibition was reversed by naltroxone (10−8 M), a μ-opioid receptor blocker, indicating that the inhibition of NOS by EtOH is mediated by β-endorphin. EtOH also blocked N-methyl-d-aspartic acid-induced LHRH release, but the blockade could not be reversed by either the GABA receptor blocker, bicuculline (10−5 M), naltroxone (10−8 M), or both inhibitors added together. However, increasing the concentration of naltrexone (10−6 M) but not bicuculline (10−4 M) reversed the inhibition. When we lowered the concentration of EtOH (50 mM), the EtOH-induced blockade of LHRH release could be reversed by either bicuculline (10−5 M), naltroxone (10−8 M), or the combination of the two blockers. Therefore, GABA is partially responsible for the blockade of N-methyl-d-aspartic acid-induced LHRH release. The block by GABA was exerted by inhibiting the activation of cyclooxygenase by NO, because it was reversed by prostaglandin E2, the product of activation of cyclooxygenase. Because the inhibition caused by the higher concentration of EtOH could not be reduced by bicuculline (10−4 M) but was blocked by naltroxone (10−6 M), the action of alcohol can be accounted for by stimulation of β-endorphin neurons that inhibit LHRH release by inhibition of activation of NOS and stimulation of GABA release. PMID:10688896

  12. Alcohol inhibits luteinizing hormone-releasing hormone release by activating the endocannabinoid system

    PubMed Central

    Fernández-Solari, Javier; Scorticati, Camila; Mohn, Claudia; De Laurentiis, Andrea; Billi, Silvia; Franchi, Ana; McCann, Samuel M.; Rettori, Valeria

    2004-01-01

    We hypothesized that ethanol (EtOH) might act through the endocannabinoid system to inhibit luteinizing hormone-releasing hormone (LHRH) release. Therefore, we examined the mechanism by which EtOH and anandamide (AEA), an endogenous cannabinoid, inhibit LHRH release from incubated medial basal hypothalamic explants. In previous work, we demonstrated that EtOH inhibits the N-methyl-d-aspartic acid-stimulated release of LHRH by increasing the release of two neurotransmitters: β-endorphin and γ-aminobutyric acid (GABA). In the present work, bicuculline, a GABAergic antagonist, completely prevented the inhibition of AEA (10-9M) on N-methyl-d-aspartic acid-induced LHRH release, but naltrexone, a μ-opioid receptor antagonist, had no effect. AEA also significantly increased GABA release but had no effect on β-endorphin release. Therefore, AEA could inhibit LHRH release by increasing GABA but not β-endorphin release. Because EtOH and AEA acted similarly to inhibit LHRH release, we investigated whether both substances would affect the adenylate cyclase activity acting through the same GTP-coupled receptors, the cannabinoid receptors 1 (CB1-rs). AEA and EtOH (10-1M) reduced the forskolin-stimulated accumulation of cAMP, but AM251, a specific antagonist of CB1-r, significantly blocked that inhibition. Additionally we investigated whether CB1-r is involved in the inhibition of LHRH by EtOH and AEA. AEA and EtOH reduced forskolin-stimulated LHRH release, but AM251 significantly blocked that inhibition. Also, we demonstrated that EtOH did not act by increasing AEA synthase activity to inhibit LHRH release in our experimental conditions. Therefore, our results indicate that EtOH inhibits the release of LHRH acting through the endocannabinoid system. PMID:14981261

  13. Ribonucleotides and RNA Promote Peptide Chain Growth.

    PubMed

    Griesser, Helmut; Tremmel, Peter; Kervio, Eric; Pfeffer, Camilla; Steiner, Ulrich E; Richert, Clemens

    2017-01-24

    All known forms of life use RNA-mediated polypeptide synthesis to produce the proteins encoded in their genes. Because the principal parts of the translational machinery consist of RNA, it is likely that peptide synthesis was achieved early in the prebiotic evolution of an RNA-dominated molecular world. How RNA attracted amino acids and then induced peptide formation in the absence of enzymes has been unclear. Herein, we show that covalent capture of an amino acid as a phosphoramidate favors peptide formation. Peptide coupling is a robust process that occurs with different condensation agents. Kinetics show that covalent capture can accelerate chain growth over oligomerization of the free amino acid by at least one order of magnitude, so that there is no need for enzymatic catalysis for peptide synthesis to begin. Peptide chain growth was also observed on phosphate-terminated RNA strands. Peptide coupling promoted by ribonucleotides or ribonucleotide residues may have been an important transitional form of peptide synthesis that set in when amino acids were first captured by RNA. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Evaluation of the Biological Properties and the Enzymatic Stability of Glycosylated Luteinizing Hormone-Releasing Hormone Analogs.

    PubMed

    Moradi, Shayli Varasteh; Varamini, Pegah; Toth, Istvan

    2015-09-01

    The enzymatic stability, antitumor activity, and gonadotropin stimulatory effects of glycosylated luteinizing hormone-releasing hormone (LHRH) analogs were investigated in this study. Conjugation of carbohydrate units, including lactose (Lac), glucose (GS), and galactose (Gal) to LHRH peptide protected the peptide from proteolytic degradation and increased the peptides' half-lives in human plasma, rat kidney membrane enzymes, and liver homogenate markedly. Among all seven modified analogs, compound 1 (Lac-[Q(1)][w(6)]LHRH) and compound 6 (GS(4)-[w(6)]LHRH) were stable in human plasma during 4 h of experiment. The half-lives of compounds 1 and 6 improved significantly in kidney membrane enzymes (from 3 min for LHRH to 68 and 103 min, respectively). The major cleavage sites for most of the glycosylated compounds were found to be at Trp(3)-Ser(4) and Ser(4)-Tyr(5) in compounds 1-5. Compound 6 was hydrolyzed at Ser(4)-Tyr(5) and the sugar conjugation site. The antiproliferative activity of the glycopeptides was evaluated on LHRH receptor-positive prostate cancer cells. The glycosylated LHRH derivatives had a significant growth inhibitory effect on the LNCaP cells after a 48-h treatment. It was demonstrated that compound 1 significantly increased the release of luteinizing hormone (LH) at 5 and 10 nM concentrations and compound 5 (GS-[Q(1)]LHRH) stimulated the release of follicle-stimulating hormone (FSH) at 5 nM concentration in dispersed rat pituitary cells (p < 0.05). In our studies, compound 1-bearing lactose and D-Trp was the most stable and active and is a promising candidate for future preclinical investigations in terms of in vitro biological activity and metabolic stability.

  15. Precocious puberty associated with neurofibromatosis and optic gliomas. Treatment with luteinizing hormone releasing hormone analogue.

    PubMed

    Laue, L; Comite, F; Hench, K; Loriaux, D L; Cutler, G B; Pescovitz, O H

    1985-11-01

    Seven children with central precocious puberty and either neurofibromatosis and/or optic gliomas were referred to the National Institutes of Health, Bethesda, Md, for evaluation and treatment with the long-acting luteinizing hormone releasing hormone analogue (LHRHa) D-Trp6-Pro9-NEt-LHRH. Only six of the seven children chose to receive treatment. Four children presented with neurofibromatosis, three of whom also had optic gliomas; the remaining three children had isolated optic gliomas, without other neurocutaneous stigmas. All had central precocious puberty mediated by activation of the hypothalamic-pituitary-gonadal axis. Six months of LHRHa therapy caused suppression of gonadotropin and sex steroid levels, stabilization or regression of secondary sexual characteristics, and decreases in growth velocity and the rate of bone age maturation. We conclude that LHRHa therapy is effective in the treatment of central precocious puberty secondary to neurofibromatosis and/or optic gliomas.

  16. Suppression of androgen production by D-tryptophan-6-luteinizing hormone-releasing hormone in man.

    PubMed Central

    Tolis, G; Mehta, A; Comaru-Schally, A M; Schally, A V

    1981-01-01

    Four male transsexual subjects were given a superactive luteinizing hormone-releasing hormone (LHRH) analogue, D-tryptophan-6-LHRH at daily doses of 100 micrograms for 3--6 mo. A decrease in beard growth, acne, and erectile potency was noted; the latter was documented objectively with the recordings of nocturnal penile tumescence episodes. Plasma testosterone and dihydrotestosterone levels fell to castrate values; basal prolactin and luteinizing hormone levels showed a small decline, whereas the acutely releasable luteinizing hormone was significantly suppressed. A rise of plasma testosterone from castrate to normal levels was demonstrable with the use of human chorionic gonadotropin. Discontinuation of treatment led to a normalization of erectile potency and plasma testosterone. The suppression of Leydig cell function by D-tryptophan-6-LHRH might have wide application in reproductive biology and in endocrine-dependent neoplasia (where it could replace surgical castration). PMID:6456277

  17. Short Anabolic Peptides for Bone Growth.

    PubMed

    Amso, Zaid; Cornish, Jillian; Brimble, Margaret A

    2016-07-01

    Loss of bone occurs in the age-related skeletal disorder, osteoporosis, leading to bone fragility and increased incidence of fractures, which are associated with enormous costs and substantial morbidity and mortality. Recent data indicate that osteoporotic fractures are more common than other diseases, which usually attract public attention (e.g., heart attack and breast cancer). The prevention and treatment of this skeletal disorder are therefore of paramount importance. Majority of osteoporosis medications restore skeletal balance by reducing osteoclastic activity, thereby reducing bone resorption. These agents, however, do not regenerate damaged bone tissue, leaving limited options for patients once bone loss has occurred. Recently, attention has turned to bone-anabolic agents. Such agents have the ability to increase bone mass and strength, potentially reversing structural damage. To date, only one bone-anabolic drug is available in the market. The discovery of more novel, cost-effective bone anabolic agents is therefore a priority to treat those suffering from this disabling condition. Short peptides offer an important alternative for the development of novel bone-anabolic agents given their high target binding specificity, which translates into potent activity with limited side effects. This review summarizes attempts in the identification of bone-anabolic peptides, and their development for promoting bone growth. © 2016 Wiley Periodicals, Inc.

  18. Copper-catalyzed N-arylation of semicarbazones for the synthesis of aza-arylglycine-containing aza-peptides.

    PubMed

    Proulx, Caroline; Lubell, William D

    2010-07-02

    Parallel synthesis of 13 aza-arylglycine peptides, based on the hexapeptide sequence of Growth Hormone Releasing Peptide-6 (GHRP-6), was accomplished via selective N-arylation of a semicarbazone peptide building block anchored on Rink amide resin. Aza-peptides possessing aza-indolylglycine and aza-imidazoylglycine residues were obtained through use of the corresponding heteroaryl iodides, yielding, respectively, aza-Trp and aza-His peptidomimics. CD spectroscopy indicated the propensity for aza-peptides, containing aza-arylglycines at the Trp(4) position of the GHRP-6 sequence, to adopt beta-turns.

  19. Chemical agents and peptides affect hair growth.

    PubMed

    Uno, H; Kurata, S

    1993-07-01

    During the past decade we have examined both the therapeutic and the prophylactic effects of several agents on the macaque model of androgenetic alopecia. Minoxidil and diazoxide, potent hypotensive agents acting as peripheral vasodilators, are known to have a hypertrichotic side effect. Topical use of both agents induced significant hair regrowth in the bald scalps of macaques. The application of a steroid 5 alpha-reductase inhibitor (4MA) in non-bald preadolescent macaques has prevented baldness, whereas controls developed it during 2 years of treatment. The effects of hair growth were determined by 1) phototrichogram, 2) folliculogram (micro-morphometric analysis), and 3) the rate of DNA synthesis in the follicular cells. These effects were essentially a stimulation of the follicular cell proliferation, resulting in an enlargement of the anagen follicles from vellus to terminal type (therapy) or a maintenance of the prebald terminal follicles (prevention). A copper binding peptide (PC1031) had the effect of follicular enlargement on the back skin of fuzzy rats, covering the vellus follicles; the effect was similar to that of topical minoxidil. Analyzing the quantitative sequences of follicular size and cyclic phases, we speculate on the effect of agents on follicular growth. We also discuss the triggering mechanism of androgen in the follicular epithelial-mesenchymal (dermal papilla) interaction.

  20. Action of luteinizing hormone-releasing hormone: involvement of novel arachidonic acid metabolites.

    PubMed Central

    Snyder, G D; Capdevila, J; Chacos, N; Manna, S; Falck, J R

    1983-01-01

    Anterior pituitary cells were incubated in the presence of luteinizing hormone-releasing hormone and one of three inhibitors of arachidonic acid metabolism:indomethacin, an inhibitor of the cyclooxygenase system; nordihydroguaiaretic acid, an antioxidant that inhibits lipoxygenase; and icosatetraynoic acid, an acetylenic analogue of arachidonic acid that blocks all known pathways of arachidonic acid metabolism. Indomethacin was ineffective in blocking luteinizing hormone-releasing hormone-stimulated luteinizing hormone secretion. Nordihydroguaiaretic acid was only marginally capable of inhibiting luteinizing hormone-releasing hormone-stimulated luteinizing hormone secretion. Icosatetraynoic acid at 10 microM completely inhibited stimulated luteinizing hormone secretion. Addition of several epoxygenated arachidonic acid metabolites to cells in vitro resulted in secretion of luteinizing hormone equal to or greater than that induced by 10 nM luteinizing hormone-releasing hormone. The half-maximal effective dose for these compounds was approximately 50 nM. The 5,6-epoxyicosatrienoic acid was the most potent of the compounds tested. These studies suggest that luteinizing hormone-releasing hormone-stimulated luteinizing hormone release is closely coupled with the production of oxidized arachidonic acid metabolites. Moreover, one or more of the epoxygenated arachidonic acid metabolites might be a component of the cascade of reactions initiated by luteinizing hormone-releasing hormone that ultimately results in secretion of luteinizing hormone. PMID:6344087

  1. Hydroxyapatite Growth Inhibition Effect of Pellicle Statherin Peptides.

    PubMed

    Xiao, Y; Karttunen, M; Jalkanen, J; Mussi, M C M; Liao, Y; Grohe, B; Lagugné-Labarthet, F; Siqueira, W L

    2015-08-01

    In our recent studies, we have shown that in vivo-acquired enamel pellicle is a sophisticated biological structure containing a significant portion of naturally occurring salivary peptides. From a functional aspect, the identification of peptides in the acquired enamel pellicle is of interest because many salivary proteins exhibit functional domains that maintain the activities of the native protein. Among the in vivo-acquired enamel pellicle peptides that have been newly identified, 5 peptides are derived from statherin. Here, we assessed the ability of these statherin pellicle peptides to inhibit hydroxyapatite crystal growth. In addition, atomistic molecular dynamics (MD) simulations were performed to better understand the underlying physical mechanisms of hydroxyapatite growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite growth. Statherin protein, 5 statherin-derived peptides, and a peptide lacking phosphate at residues 2 and 3 were analyzed. Statherin peptide phosphorylated on residues 2 and 3 indicated a significant inhibitory effect when compared with the 5 other peptides (P < 0.05). MD simulations showed a strong affinity and fast adsorption to hydroxyapatite for phosphopeptides, whereas unphosphorylated peptides interacted weakly with the hydroxyapatite. Our data suggest that the presence of a covalently linked phosphate group (at residues 2 and 3) in statherin peptides modulates the effect of hydroxyapatite growth inhibition. This study provides a mechanism to account for the composition and function of acquired enamel pellicle statherin peptides that will contribute as a base for the development of biologically stable and functional synthetic peptides for therapeutic use against dental caries and/or periodontal disease.

  2. Rationally designed cyclic analogues of luteinizing hormone-releasing hormone: enhanced enzymatic stability and biological properties.

    PubMed

    Laimou, Despina; Katsila, Theodora; Matsoukas, John; Schally, Andrew; Gkountelias, Kostas; Liapakis, George; Tamvakopoulos, Constantin; Tselios, Theodore

    2012-12-01

    This article describes the rational design, synthesis and pharmacological properties of amide-linked cyclic analogues of Luteinizing Hormone-Releasing Hormone (LHRH) with substitutions at positions 1 (Pro), 6 (D-Leu/D-Trp), 9 (Aze) and 10 (BABA/Acp). These LHRH analogues fulfil the conformational requirements that are known in the literature (bend in the 5-8 segment) to be essential for receptor recognition and activation. Although, they are characterised by an overall low binding affinity to the LHRH-I receptor, the cyclic analogues that were studied and especially the cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH, exhibit a profoundly enhanced in vitro and in vivo stability and improved pharmacokinetics in comparison with their linear counterpart and leuprolide. Upon receptor binding, cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH causes testosterone release in C57/B16 mice (in vivo efficacy) that is comparable to that of leuprolide. Testosterone release is an acutely dose dependent effect that is blocked by the LHRH-I receptor antagonist, cetrorelix. The pharmacokinetic advantages and efficacy of cyclo(1-10)[Pro(1), D-Leu(6), BABA(10)] LHRH render this analogue a promising platform for future rational drug design studies towards the development of non-peptide LHRH mimetics.

  3. In vivo pharmacological evaluation of a lactose-conjugated luteinizing hormone releasing hormone analogue.

    PubMed

    Moradi, Shayli Varasteh; Varamini, Pegah; Steyn, Frederik; Toth, Istvan

    2015-11-10

    In the current study, the efficacy and pharmacokinetic profile of lactose-conjugated luteinizing hormone releasing hormone (LHRH) was examined following oral administration in male rats. A rapid and sensitive liquid chromatography/mass spectrometry technique was developed and applied for measuring the concentration of lactose[Q(1)][w(6)]LHRH (compound 1) in rat plasma in order to allow measurement of pharmacokinetic parameters. LH release was evaluated using a sandwich ELISA. Maximum serum concentration (Cmax = 0.11 μg/ml) was reached at 2h (Tmax) following oral administration of the compound at 10mg/kg. The half-life was determined to be 2.6h. The absolute bioavailability of the orally administered compound was found to be 14%, which was a remarkable improvement compared to zero-to-low oral bioavailability of the native peptide. Compound 1 was effective in stimulating LH release at 20mg/kg after oral administration. The method was validated at a linear range of 0.01-20.0 μg/ml and a correlation coefficient of r(2) ≥ 0.999. The accuracy and precision values showed the reliability and reproducibility of the method for evaluation of the pharmacokinetic parameters. These findings showed that the lactose derivative of LHRH has a therapeutic potential to be further developed as an orally active therapeutics for the treatment of hormone-dependent diseases.

  4. Establishment and clinical application of enzyme immunoassays for determination of luteinizing hormone releasing hormone and metastin.

    PubMed

    Katagiri, Fumihiko; Tomita, Kenji; Oishi, Shinya; Takeyama, Masaharu; Fujii, Nobutaka

    2007-06-01

    Metastin, a 54-residue peptide, was identified as the cognate ligand of human G-protein-coupled receptor GPR54. Since metastin is a gene product of the human metastasis suppressor gene 'KiSS-1', early studies on metastin were focused on its activity as a tumor metastasis suppressor. Recently, there have been some reports that metastin is found in human plasma and is particularly abundant in the plasma of pregnant women. Dysfunction of the GPR54 receptor causes diseases that are characterized by an insufficient release of gonadotropin and lack or delay of pubertal maturation. This information strongly suggests that metastin is involved in the regulation of reproductive endocrine functions. In order to determine the plasma levels of metastin and luteinizing hormone releasing hormone (LHRH) in an isolated hypogonadotropic hypogonadism (IHH) patient, who received intermittent administrations of LHRH, we tried to establish a sensitive and specific enzyme immunoassay. The plasma LHRH levels of the patient were very high, while plasma metastin levels were at almost the same levels as circadian rhythms of healthy male humans. In the central nervous system, metastin stimulates the neuroendocrine reproductive axis. However, the effects of peripheral metastin are not known. Our result suggested that peripheral metastin had a genesis and activity different from central metastin.

  5. Hypothalamic hypopituitarism in a patient with a basal encephalocoele--treatment with luteinizing hormone-releasing hormone.

    PubMed Central

    Morris, D. V.; Mason, W. P.; Wilson-Holt, N.; Adams, J.; Keene, M.; Tanner, J.; Jacobs, H. S.

    1984-01-01

    A 20-year-old patient presented with primary amenorrhoea and growth hormone deficiency caused by a basal encephalocoele. She was found to have developed diabetes insipidus in the 8 years following diagnosis. Gonadotrophin release in response to bolus injection of luteinizing hormone-releasing hormone (LHRH) was normal, as was thyrotrophin and adrenocorticotrophin (ACTH) secretion. Pulsatile administration of LHRH by the subcutaneous route resulted in normal ovulation and subsequent menstruation. The investigation and management of patients with basal encephalocoeles are discussed in the light of these findings. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:6384984

  6. 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.

  7. Decapeptides as effective agonists from L-amino acids biologically equivalent to the luteinizing hormone-releasing hormone.

    PubMed Central

    Folkers, K; Bowers, C Y; Tang, P F; Kubota, M

    1986-01-01

    Apparently, no agonist has been found that is comparable in potency to the luteinizing hormone-releasing hormone (LHRH) for release of LH and follicle-stimulating hormone (FSH) without substitutions with unnatural or D forms of natural amino acids. Of 139 known "agonist analogs" of LHRH, two were active in the range of 65%. The four LHRHs known to occur in nature involve a total of six amino acids (Tyr, His, Leu, Trp, Arg, Gln) in positions 5, 7, and 8. There are 16 possible peptides with these six amino acids in positions 5, 7, and 8, of which 4 are the known LHRHs, and 2 more were synthesized. We have synthesized the 10 new peptides and assayed 11 in vivo and in vitro, and we found not only 1 but a total of 5 that have activity equivalent to or greater than that of LHRH for the release of LH and/or FSH under at least one assay condition. These five are as follows: [His5,Trp7,Gln8]LHRH; [His5,Trp7,Leu8]LHRH; [His5,Trp7]LHRH; [Trp7]LHRH; [His5]LHRH. Two of these five agonists variably released relatively more FSH than LH. One or more of these five agonists may occur in nature and one may be follicle-stimulating hormone-releasing hormone. The two peptides with Gln8 and Leu8, if occurring in nature, may have different receptors according to radioreceptor assays and to the ratio of LH/FSH release in vivo. These structures are a basis for the design of antagonists without Arg8 toward avoiding histamine release. Complete inhibition of LH and FSH release in vivo may be induced by joint use of Arg8 and Gln8 or Leu8 antagonists. These potent agonists, related to LHRH, may be therapeutically useful in disorders of reproduction, the central nervous system, and for the control of hormone-dependent carcinomas. PMID:3081889

  8. L-arginine promotes gut hormone release and reduces food intake in rodents.

    PubMed

    Alamshah, A; McGavigan, A K; Spreckley, E; Kinsey-Jones, J S; Amin, A; Tough, I R; O'Hara, H C; Moolla, A; Banks, K; France, R; Hyberg, G; Norton, M; Cheong, W; Lehmann, A; Bloom, S R; Cox, H M; Murphy, K G

    2016-05-01

    To investigate the anorectic effect of L-arginine (L-Arg) in rodents. We investigated the effects of L-Arg on food intake, and the role of the anorectic gut hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), the G-protein-coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. Oral gavage of L-Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet-induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L-Arg stimulated GLP-1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP-1 and PYY receptors did not influence the anorectic effect of L-Arg. L-Arg-mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L-Arg suppressed food intake in rats. L-Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L-Arg is unlikely to be mediated by GLP-1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L-Arg suppressed food intake in rats, suggesting that L-Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L-Arg suppresses food intake and its utility in the treatment of obesity. © 2016 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  9. Biosynthesis and the conjugation of magnetite nanoparticles with luteinizing hormone releasing hormone (LHRH).

    PubMed

    Obayemi, J D; Dozie-Nwachukwu, S; Danyuo, Y; Odusanya, O S; Anuku, N; Malatesta, K; Soboyejo, W O

    2015-01-01

    This paper presents the results of an experimental study of the biosynthesis of magnetite nanoparticles (BMNPs) with particle sizes between 10 nm and 60 nm. The biocompatible magnetic nanoparticles are produced from Magnetospirillum magneticum (M.M.) bacteria that respond to magnetic fields. M.M. bacteria were cultured and used to synthesize magnetite nanoparticles. This was done in an enriched magnetic spirillum growth medium (EMSGM) at different pH levels. The nanoparticle concentrations were characterized with UV-Visible (UV-Vis) spectroscopy, while the particle shapes were elucidated via transmission electron microscopy (TEM). The structure of the particles was studied using X-ray diffraction (XRD), while the hydrodynamic radii, particle size distributions and polydispersity of the nanoparticles were characterized using dynamic light scattering (DLS). Carbodiimide reduction was also used to functionalize the BMNPs with a molecular recognition unit (luteinizing hormone releasing hormone, LHRH) that attaches specifically to receptors that are over-expressed on the surfaces of most breast cancer cell types. The resulting nanoparticles were examined using Fourier Transform Infrared (FTIR) spectroscopy and quantitative image analysis. The implications of the results are then discussed for the potential development of magnetic nanoparticles for the specific targeting and treatment of breast cancer. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Postdiffusion of oligo-peptide within exponential growth multilayer films for localized peptide delivery.

    PubMed

    Wang, Xuefei; Ji, Jian

    2009-10-06

    The multilayers of poly(L-lysine) (PLL) and hyaluronic acid (HA) were constructed by alternating deposition of PLL at high pH and HA at low pH. The exponential growth of the multilayer was proved to be amplified by increasing the pH difference between the two deposition solutions. The exponential growth multilayers of PLL/HA assembled at different pH were utilized as reservoirs for loading a trans-activating transcriptional factor (TAT) peptide. The confocal laser scanning microscopy (CLSM) results indicated that the FITC-labeled TAT could diffuse throughout the exponentially growing PLL/HA film. The amount of peptide embedded within multilayer could be adjusted by both multilayer assembly pH and the TAT loading pH. Compared with (PLL/HA 6.5/6.5)5 multilayer (PLL/HA a/b means that the multilayer film was constructed by using PLL at pH a and HA at pH b), the (PLL/HA 9.5/2.9)5 film can be loaded with more TAT peptide at the same loading pH 6.5. The excess of positively charged TAT peptide within (PLL/HA 9.5/2.9)5 film could not only be ascribed to its extraordinary thickness but also be attributed to its uncompensated negative charge density enhanced by the pH difference between film buildup and peptide loading process. Increasing of the TAT loading pH from 6.5 to 9.5, which increases the pH difference between multilayer assembly and peptide loading process, enhances the uncompensated charge density within (PLL/HA 9.5/2.9)5 film and elevates the peptide density from 13.8 to 25.0 microg/cm2. Compared with direct layer-by-layer assembly of TAT and HA, the postdiffusion of TAT into (PLL/HA 9.5/2.9)5 film was loaded much more peptide. The postdiffusion of peptide into a rapid growth multilayer can be more favorable to load and sustainedly release functional oligo-peptide. The cell culture results indicated that the TAT embedded within the film maintained the ability to traverse across the Hep G2 cell membrane. The functionalized (PLL/HA 9.5/2.9)5 TAT 9.5 film was more

  11. L‐arginine promotes gut hormone release and reduces food intake in rodents

    PubMed Central

    Alamshah, A.; McGavigan, A. K.; Spreckley, E.; Kinsey‐Jones, J. S.; Amin, A.; Tough, I. R.; O'Hara, H. C.; Moolla, A.; Banks, K.; France, R.; Hyberg, G.; Norton, M.; Cheong, W.; Lehmann, A.; Bloom, S. R.; Cox, H. M.

    2016-01-01

    Aims To investigate the anorectic effect of L‐arginine (L‐Arg) in rodents. Methods We investigated the effects of L‐Arg on food intake, and the role of the anorectic gut hormones glucagon‐like peptide‐1 (GLP‐1) and peptide YY (PYY), the G‐protein‐coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. Results Oral gavage of L‐Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet‐induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L‐Arg stimulated GLP‐1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP‐1 and PYY receptors did not influence the anorectic effect of L‐Arg. L‐Arg‐mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L‐Arg suppressed food intake in rats. Conclusions L‐Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L‐Arg is unlikely to be mediated by GLP‐1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L‐Arg suppressed food intake in rats, suggesting that L‐Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L‐Arg suppresses food intake and its utility in the treatment of obesity. PMID:26863991

  12. Hydroxyapatite-binding peptides for bone growth and inhibition

    DOEpatents

    Bertozzi, Carolyn R [Berkeley, CA; Song, Jie [Shrewsbury, MA; Lee, Seung-Wuk [Walnut Creek, CA

    2011-09-20

    Hydroxyapatite (HA)-binding peptides are selected using combinatorial phage library display. Pseudo-repetitive consensus amino acid sequences possessing periodic hydroxyl side chains in every two or three amino acid sequences are obtained. These sequences resemble the (Gly-Pro-Hyp).sub.x repeat of human type I collagen, a major component of extracellular matrices of natural bone. A consistent presence of basic amino acid residues is also observed. The peptides are synthesized by the solid-phase synthetic method and then used for template-driven HA-mineralization. Microscopy reveal that the peptides template the growth of polycrystalline HA crystals .about.40 nm in size.

  13. Topographical localization of the receptors for luteinizing hormone- releasing hormone on the surface of dissociated pituitary cells

    PubMed Central

    1977-01-01

    A derivative of the hypothalamic peptide luteinizing hormone-releasing hormone (LHRH) has been coupled to ferritin and the conjugate purified by gel chromatography. In its ability to stimulate the secretion of luteinizing hormone from pituitary cells in vitro, the conjugate has the same potency and specificity as the native peptide. When dissociated pituitary cells maintained in short-term culture are lightly fixed with formaldehyde and then incubated with the conjugate, examination in the electron microscope shows an even distribution of ferritin particles over the free cell surface of the gonadotrophin cells. This binding appears to be specific for the LHRH receptor since it is prevented by a 10-fold excess of native peptide. In addition to the gonadotrophin cells, some somatotrophin and thyrotrophin cells bind conjugate on their free surfaces under similar conditions. If living cells are incubated with the conjugate for 15 min, the bound conjugate becomes aggregated and then concentrated in one localized area of the cell surface. In this area, which lies immediately above the juxtanuclear Golgi complex, the plasma membrane is frequently invaginated in a manner which suggests that the bound, aggregated conjugate is internalized by endocytosis. PMID:233747

  14. Hormonal Responses to Synthetic Luteinizing Hormone and Follicle Stimulating Hormone-Releasing Hormone in Man

    PubMed Central

    Besser, G. M.; McNeilly, A. S.; Anderson, D. C.; Marshall, J. C.; Harsoulis, P.; Hall, R.; Ormston, B. J.; Alexander, L.; Collins, W. P.

    1972-01-01

    The effects of the gonadotrophin-releasing hormone, synthetic decapeptide luteinizing hormone/follicle stimulating hormone-releasing hormone (LH/FSH-RH), have been studied in 18 normal men and five women in the follicular phase of their menstrual cycle. Rapid and dose-dependent (25 to 100 μg) increases in serum immunoreactive LH were seen, which reached a peak 20 to 30 minutes after a rapid intravenous injection. Similar but much smaller increases in serum immunoreactive FSH were seen. These conclusions have been validated by using two different immunoassay systems for each hormone. The LH/FSH-RH therefore causes both LH and FSH release in man as in animals but does not affect growth hormone, thyrotrophin, or ACTH. The gonadotrophin responses were the same in the women as in the men but were insufficient in the men to cause statistically significant changes in the serum levels of the gonadal steroid hormones, testosterone or oestradiol, or in their precursors 17 α-hydroxyprogesterone or progesterone. In the women, however, there was a rise in oestradiol after the 100-μg doses. The use of LH/FSH-RH will provide an important test to define the level of the lesion in hypogonadal patients and also should be valuable in the treatment of some types of male and female infertility. A simple and clinically useful LH/FSH-RH test of pituitary function is described (100 μg given intravenously), and the provisional normal responses of LH and FSH at 20 and 60 minutes are given. PMID:4339974

  15. Progression of intracranial meningioma during luteinizing hormone-releasing hormone agonist treatment for prostate cancer: case report.

    PubMed

    Anda, Takeo; Honda, Masaru; Ishihara, Tokuhiro; Kamei, Toshiaki

    2014-01-01

    The authors describe a male patient who developed a large intracranial meningioma during the hormone therapy for pre-existing prostate cancer. A 70-year-old man received a brain check-up, and no intracranial abnormality was detected. Five months later, prostate cancer was diagnosed, and he underwent prostatectomy. Leuprorelin acetate, a luteinizing hormone-releasing hormone (LH-RH) agonist, was subsequently administered to the patient once a month for 3 years. After that he presented with a large parasagittal mass, which was excised. The tumor was histologically diagnosed as meningothelial meningioma, and LH-RH receptors were verified immunohistochemically in the cytoplasm of the tumor cells. Leuprorelin acetate may accelerate the rapid growth of meningioma in this patient.

  16. Progression of Intracranial Meningioma during Luteinizing Hormone-Releasing Hormone Agonist Treatment for Prostate Cancer: Case Report

    PubMed Central

    ANDA, Takeo; HONDA, Masaru; ISHIHARA, Tokuhiro; KAMEI, Toshiaki

    2014-01-01

    The authors describe a male patient who developed a large intracranial meningioma during the hormone therapy for pre-existing prostate cancer. A 70-year-old man received a brain check-up, and no intracranial abnormality was detected. Five months later, prostate cancer was diagnosed, and he underwent prostatectomy. Leuprorelin acetate, a luteinizing hormone-releasing hormone (LH-RH) agonist, was subsequently administered to the patient once a month for 3 years. After that he presented with a large parasagittal mass, which was excised. The tumor was histologically diagnosed as meningothelial meningioma, and LH-RH receptors were verified immunohistochemically in the cytoplasm of the tumor cells. Leuprorelin acetate may accelerate the rapid growth of meningioma in this patient. PMID:24201100

  17. Antiproliferative and GH-inhibitory activity of chimeric peptides consisting of GHRP-6 and somatostatin.

    PubMed

    Dasgupta, P; Singh, A T; Mukherjee, R

    1999-06-07

    Chimeric peptides consisting of growth hormone releasing peptide (GHRP-6) linked to somatostatin (6-11) via an amide bond to provide the effector parts of both the peptides were synthesized. The anti-proliferative, cytotoxic, and GH-inhibitory activities of these chimeric peptides were determined in vitro in the rat pituitary adenoma cell line GH3. One of the chimeric peptides, GSD, exhibited significantly greater (p < 0.001) anti-neoplastic and GH-inhibitory activity, as compared to RC-160. The hybrid peptides displayed high affinity binding to somatostatin receptors on GH3 cells. The bioactivity of GSD was found to be mediated by the stimulation of tyrosine phosphatase, involving a cGMP-dependent pathway, through pertussis toxin-sensitive G-proteins. Such potent GH-inhibitory chimeric peptides may be of potential importance in the therapy of acromegaly, as well as provide novel tools to study the regulation of GH secretion by GHRP and somatostatin.

  18. Luteinizing Hormone-Releasing Hormone Distribution in the Anterior Hypothalamus of the Female Rats

    PubMed Central

    Castañeyra-Ruiz, Leandro; González-Marrero, Ibrahim; Castañeyra-Ruiz, Agustín; González-Toledo, Juan M.; Castañeyra-Ruiz, María; de Paz-Carmona, Héctor; Castañeyra-Perdomo, Agustín; Carmona-Calero, Emilia M.

    2013-01-01

    Luteinizing hormone-releasing hormone (LHRH) neurons and fibers are located in the anteroventral hypothalamus, specifically in the preoptic medial area and the organum vasculosum of the lamina terminalis. Most luteinizing hormone-releasing hormone neurons project to the median eminence where they are secreted in the pituitary portal system in order to control the release of gonadotropin. The aim of this study is to provide, using immunohistochemistry and female brain rats, a new description of the luteinizing hormone-releasing hormone fibers and neuron localization in the anterior hypothalamus. The greatest amount of the LHRH immunoreactive material was found in the organum vasculosum of the lamina terminalis that is located around the anterior region of the third ventricle. The intensity of the reaction of LHRH immunoreactive material decreases from cephalic to caudal localization; therefore, the greatest immunoreaction is in the organum vasculosum of the lamina terminalis, followed by the dorsomedial preoptic area, the ventromedial preoptic area, and finally the ventrolateral medial preoptic area, and in fibers surrounding the suprachiasmatic nucleus and subependymal layer on the floor of the third ventricle where the least amount immunoreactive material is found. PMID:25938107

  19. Taurine and the control of basal hormone release from rat neurohypophysis.

    PubMed

    Song, Zhilin; Hatton, Glenn I

    2003-10-01

    Pituicytes of pituitary neural lobe are rich in the amino acid taurine, which they release upon hypoosmotic stimulation. As a generally inhibitory amino acid, taurine is thought to activate receptors on neural lobe nerve terminals and exert some control over hormone release. Previous work has shown the presence of glycine and GABA(A) receptors in neural lobe, both of which have affinity for taurine. Using a perifused explant system, we studied the effects of taurine activation of glycine and GABA(A) receptors on basal hormone release. Somewhat surprisingly, taurine induced increases in basal release of both vasopressin and oxytocin. Taurine-induced increases in oxytocin release were blocked by bicuculline, suggesting involvement of GABA(A) receptors. Increases in vasopressin release were not blocked by bicuculline, indicating involvement of receptors other than GABA(A). Although combined bicuculline and strychnine, an antagonist at most glycine receptors, also did not block increased vasopressin release, picrotoxin (a Cl(-) channel blocker) was effective in blocking increases in both vasopressin and oxytocin release. The other receptor(s) involved in taurine actions is postulated to be strychnine-insensitive glycine receptors. Thus, taurine in neural lobe may act via both a GABA(A) receptor and one or more types of glycine receptors to depolarize nerve terminal membranes under basal conditions. Taurine-induced partial depolarization resulting in Na(+) channel inactivation is probably responsible for its previously observed inhibition of stimulated hormone release from neural lobe.

  20. Distribution of luteinizing hormone-releasing hormone in the upper brainstem and diencephalon of the cat: an immunocytochemical study.

    PubMed

    Belda, M; Coveñas, R; Narváez, J A; Aguirre, J A; Tramu, G

    2000-03-01

    The distribution of luteinizing hormone-releasing hormone (LH-RH)-immunostained cell bodies and fibres was studied in the brainstem and diencephalon of the cat using an indirect immunoperoxidase technique. The brainstem and the thalamus were devoid of immunostained cell bodies, whereas in the hypothalamus immunopositive perikarya were observed in the supraoptic nucleus, the anterior hypothalamus, the preoptic region and in the arcuate nucleus. Our findings also showed that the hypothalamus is richer in immunostained fibres, and that in this region such fibres are more widely distributed than in the thalamus and upper brainstem. No immunopositive fibres were observed in the lower brainstem. Our results point to a more widespread distribution of LH-RH-immunostained perikarya in the cat hypothalamus than that previously reported in the cat; a similar distribution to that found in the rat, and a more restricted distribution than in primates. Additionally, our study shows a more widespread distribution of immunostained fibres in the cat brainstem and diencephalon than that previously described for other mammals. In this context, our results describe for the first time in the mammals central nervous system fibres containing LH-RH located in the stria medullaris of the thalamus, the supramammillary decussation, the laterodorsal and lateroposterior thalamic nuclei, the nucleus reuniens, the supraoptic nucleus, and the optic chiasm. Thus, our findings reveal that LH-RH-immunostained structures are widely distributed in the upper brainstem and in the diencephalon of the cat, suggesting that the peptide may be involved in several physiological functions.

  1. Targeted chemotherapy of endometrial, ovarian and breast cancers with cytotoxic analogs of luteinizing hormone-releasing hormone (LHRH).

    PubMed

    Engel, J B; Schally, A V; Buchholz, S; Seitz, S; Emons, G; Ortmann, O

    2012-08-01

    Receptors luteinizing hormone-releasing hormone (LHRH) are expressed in about 80 % of human endometrial and ovarian cancers and account for more than 50 % of breast cancers including triple negative breast cancers. Apart from the pituitary and reproductive organs, no other organs or hematopoietic stem cells express LHRH (GnRH) receptors. Thus, these receptors can be regarded as an ideal target for a personalized medicine approach in cancer therapy. AEZS-108 (formerly known as AN-152) in which doxorubin is linked to the LHRH agonist [D: -Lys(6)]LHRH, appears to be the most advanced compound in late stage clinical development. Results of phase I and phase II clinical trials in patients with gynecological cancers demonstrated anticancer activity without any cardiotoxicity even in highly pretreated patients. AEZS-108 is therefore being considered for phase II trials in triple negative breast cancers and phase III studies in advanced endometrial cancers positive for LHRH-receptor. EP-100 is a membrane-disrupting peptide targeted to LHRH receptors, which is undergoing early clinical studies in ovarian cancer patients.

  2. Corpus luteum derived copper, zinc-superoxide dismutase serves as a luteinizing hormone-release inhibiting factor in sheep.

    PubMed

    Al-Gubory, Kaïs H; Huet, Jean-Claude; Pernollet, Jean-Claude; Martal, Jacques; Locatelli, Alain

    2003-01-31

    In the present study, we report the purification and characterization of a polypeptide from the sheep corpus luteum of pregnancy with a potent luteinizing hormone-release inhibiting factor (LH-RIF) bioactivity that stained as a single band in SDS-PAGE with an apparent molecular mass of 16000 Da. The amino acid sequences obtained after sequence analysis of peptides derived from the trypsin digestion of LH-RIF were subjected to a protein data bank search and were found to be identical with regions of sheep copper, zinc-superoxide dismutase (Cu,Zn-SOD). The measured mass of LH-RIF (15604.2+/-1.9 Da) was found to be similar to the theoretical mass of sheep Cu,Zn-SOD (15603.5 Da), with a disulfide bond and N acetylated alanine at the N-terminus. The inhibitory action of Cu,Zn-SOD on pulsatile LH secretion would suggest that this antioxidant may play an important role, either independently or in concert with some neurotransmitters, in the neuroendocrine regulation of sheep female reproductive function.

  3. Peptide microarray patterning for controlling and monitoring cell growth.

    PubMed

    Lin, Edith; Sikand, Adhirath; Wickware, Jessica; Hao, Yubin; Derda, Ratmir

    2016-04-01

    The fate of cells is influenced by their microenvironment and many cell types undergo differentiation when stimulated by extracellular cues, such as soluble growth factors and the insoluble extracellular matrix (ECM). Stimulating differentiation by insoluble or "immobilized" cues is a particularly attractive method because it allows for the induction of differentiation in a spatially-defined cohort of cells within a larger subpopulation. To improve the design of de novo screening of such insoluble factors, we describe a methodology for producing high-density peptide microarrays suitable for extended cell culture and fluorescence microscopy. As a model, we used a murine mammary gland cell line (NMuMG) that undergoes epithelial to mesenchymal transition (EMT) in response to soluble transforming growth factor beta (TGF-β) and surface-immobilized peptides that target TGF-β receptors (TGFβRI/II). We repurposed a well-established DNA microarray printing technique to produce arrays of micropatterned surfaces that displayed TGFβRI/II-binding peptides and integrin binding peptides. Upon long-term culture on these arrays, only NMuMG cells residing on EMT-stimulating areas exhibited growth arrest and decreased E-cadherin expression. We believe that the methodology created in this report will aid the development of peptide-decorated surfaces that can locally stimulate defined cell surface receptors and control EMT and other well-characterized differentiation events. Scope of work: This manuscript aims to accelerate the development of instructive biomaterials decorated with specific ligands that target cell-surface receptors and induce specific differentiation of cells upon contact. These materials can be used for practical applications, such as fabricating synthetic materials for large scale, stem cell culture, or investigating differentiation and asymmetric division in stem cells. Specifically, in this manuscript, we repurposed a DNA microarray printer to produce

  4. 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

  5. Differential involvement of signaling pathways in the regulation of growth hormone release by somatostatin and growth hormone-releasing hormone in orange-spotted grouper (Epinephelus coioides).

    PubMed

    Wang, Bin; Qin, Chaobin; Zhang, Cong; Jia, Jirong; Sun, Caiyun; Li, Wensheng

    2014-02-15

    Somatostatin is the most effective inhibitor of GH release, and GHRH was recently identified as one of the primary GH-releasing factors in teleosts. In this study, we analyzed the possible intracellular transduction pathways that are involved in the mechanisms induced by SRIF and GHRH to regulate GH release. Using a pharmacological approach, the blockade of the PLC/IP/PKC pathway reversed the SRIF-induced inhibition of GH release but did not affect the GHRH-induced stimulation of GH release. Furthermore, SRIF reduced the GH release induced by two PKC activators. Inhibitors of the AC/cAMP/PKA pathway reversed both the SRIF- and GHRH-induced effects on GH release. Moreover, the GH release evoked by forskolin and 8-Br-cAMP were completely abolished by SRIF. The blockade of the NOS/NO pathway attenuated the GHRH-induced GH release but had minimal effects on the inhibitory actions of SRIF. In addition, inhibitors of the sGC/cGMP pathway did not modify the SRIF- or GHRH-induced regulation of GH release. Taken together, these findings indicate that the SRIF-induced inhibition of GH release is mediated by both the PLC/IP/PKC and the AC/cAMP/PKA pathways and not by the NOS/NO/sGC/cGMP pathway. In contrast, the GHRH-induced stimulation of GH secretion is mediated by both the AC/cAMP/PKA and the NOS/NO pathways and is independent of the sGC/cGMP pathway and the PLC/IP/PKC system.

  6. Highly potent analogues of luteinizing hormone-releasing hormone containing D-phenylalanine nitrogen mustard in position 6.

    PubMed Central

    Bajusz, S; Janaky, T; Csernus, V J; Bokser, L; Fekete, M; Srkalovic, G; Redding, T W; Schally, A V

    1989-01-01

    The nitrogen mustard derivatives of 4-phenylbutyric acid and L-phenylalanine, called chlorambucil (Chl) and melphalan (Mel), respectively, have been incorporated into several peptide hormones, including luteinizing hormone-releasing hormone (LH-RH). The alkylating analogues of LH-RH were prepared by linking Chl, as an N-acyl moiety, to the complete amino acid sequence of agonistic and antagonistic analogues. These compounds, in particular the antagonistic analogues, showed much lower potency than their congeners carrying other acyl groups. To obtain highly potent alkylating analogues of LH-RH, the D enantiomer of Mel was incorporated into position 6 of the native hormone and some of its antagonistic analogues. Of the peptides prepared, [D-Mel6]LH-RH (SB-05) and [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Pal(3)3,Arg5,D-Mel6,D-Ala10++ +]LH-RH [SB-86, where Nal(2) is 3-(2-naphthyl)alanine and Pal(3) is 3-(3-pyridyl)alanine] possessed the expected high agonistic and antagonistic activities, respectively, and also showed high affinities for the membrane receptors of rat pituitary cells, human breast cancer cells, human prostate cancer cells, and rat Dunning R-3327 prostate tumor cells. These two analogues exerted cytotoxic effects on human and rat mammary cancer cells in vitro. Thus these two D-Mel6 analogues seem to be particularly suitable for the study of how alkylating analogues of LH-RH could interfere with intracellular events in certain cancer cells. PMID:2548207

  7. Decapeptides as effective agonists from L-amino acids biologically equivalent to the luteinizing hormone-releasing hormone

    SciTech Connect

    Folkers, K.; Bowers, C.Y.; Tang, P.L.; Kubota, M.

    1986-02-01

    Apparently, no agonist has been found that is comparable in potency to the luteinizing hormone-releasing hormone (LHRH) for release of LH and follicle-stimulating hormone (FSH) without substitutions with unnatural or D forms of natural amino acids. Of 139 known agonist analogs of LHRH, two were active in the range of 65%. The four LHRHs known to occur in nature involve a total of six amino acids (Tyr, His, Leu, Trp, Arg, Gln) in positions 5, 7, and 8. There are 16 possible peptides with these six amino acids in positions 5, 7, and 8, of which 4 are the known LHRHs, and 2 more were synthesized. The authors have synthesized the 10 new peptides and assayed 11 in vivo and in vitro, and they found not only 1 but a total of 5 that have activity equivalent to or greater than that of LHRH for the release of LH and/or FSH under at least one assay condition. These five are as follows: (HisV,TrpX,GlnY)LHRH; (HisV,TrpX,LeuY)LHRH; (HisV,TrpX)LHRH; (TrpX)LHRH; (HisV)LHRH. These structures are a basis for the design of antagonists without ArgY toward avoiding histamine release. Complete inhibition of LH and FSH release in vivo may be induced by joint use of ArgY and GlnY or LeuY antagonists. These potent agonists, related to LHRH, may be therapeutically useful in disorders of reproduction, the central nervous system, and for the control of hormone-dependent carcinomas. Radioreceptor assays and radioimmunoassays were utilized.

  8. Interaction Between Luteinizing Hormone-Releasing Hormone and GM1-Doped Cholesterol/Sphingomyelin Vesicles: A Spectroscopic Study.

    PubMed

    Shahzadi, Zarrin; Mukhopadhyay, Chaitali

    2017-09-11

    Understanding the role of neural membrane in translocation and action of neurohormone is of great importance. Luteinizing hormone-releasing hormone (LHRH) is a neuropeptide hormone and it acts as a final signaling molecule by stimulating the synthesis of LH and FSH to maintain reproduction in all vertebrates. The receptors of LHRH are found in breast tumors and pituitary gland in the brain. Moreover, neural plasma membrane is also found to contain specific binding site for LHRH. The mechanism by which LHRH binds to membrane before it binds to the receptors is a very critical step and can have a profound impact upon the translation of peptide across the membrane. A complex form of glycosphingolipids known as Ganglioside is an important component of plasma membrane of nerve cells and breast tumor tissues. They play an important role in various physiological membrane processes. Therefore, the interaction of ganglioside-containing membrane with LHRH might be crucial in aiding the LHRH to translate through the neural membrane and reach its receptor for binding and activation. Using CD, UV-Absorbance, and fluorescence spectroscopy, the effect of Ganglioside Monosialo 1(GM1)-induced conformational changes of LHRH in the presence of Cholesterol (CHOL)/Sphingomyelin (SM) and GM1/CHOL/SM vesicles was studied. The aforesaid spectroscopic studies show that LHRH is able to bind with both the vesicles, but GM1-containing vesicles interact more effectively than vesicles without GM1. CHOL/SM vesicles partially disturb the conformation of the peptide. Moreover, binding of LHRH to GM1/CHOL/SM vesicles induces loss of conformational rigidity and attainment of a random coil.

  9. Novel Antifungal Peptides Produced by Leuconostoc mesenteroides DU15 Effectively Inhibit Growth of Aspergillus niger.

    PubMed

    Muhialdin, Belal J; Hassan, Zaiton; Abu Bakar, Fatimah; Algboory, Hussein L; Saari, Nazamid

    2015-05-01

    The ability of Leuconostoc mesenteroides DU15 to produce antifungal peptides that inhibit growth of Aspergillus niger was evaluated under optimum growth conditions of 30 °C for 48 h. The cell-free supernatant showed inhibitory activity against A. niger. Five novel peptides were isolated with the sequences GPFPL, YVPLF, LLHGVPLP, GPFPLEMTLGPT, and TVYPFPGPL as identified by de novo sequencing using PEAKS 6 software. Peptide LLHGVPLP was the only positively charged (cationic peptides) and peptide GPFPLEMTLGPT negatively charged (anionic), whereas the rest are neutral. The identified peptides had high hydrophobicity ratio and low molecular weights with amino acids sequences ranging from 5 to 12 residues. The mode of action of these peptides is observed under the scanning electron microscope and is due to cell lysis of fungi. This work reveals the potential of peptides from L. mesenteroides DU15 as natural antifungal preservatives in inhibiting the growth of A. niger that is implicated to the spoilage during storage.

  10. Luteinizing hormone-releasing hormone agonists in premenopausal hormone receptor-positive breast cancer.

    PubMed

    Tan, Sing-Huang; Wolff, Antonio C

    2007-02-01

    Ovarian function suppression for the treatment of premenopausal breast cancer was first used in the late 19th century. Traditionally, ovarian function suppression had been accomplished irreversibly via irradiation or surgery, but analogues of the luteinizing hormone-releasing hormone (LH-RH) have emerged as reliable and reversible agents for this purpose, especially the LH-RH agonists. Luteinizing hormone-releasing hormone antagonists are in earlier stages of development in breast cancer and are not currently in clinical use. Luteinizing hormonereleasing hormone agonists act by pituitary desensitization and receptor downregulation, thereby suppressing gonadotrophin release. Limited information is available comparing the efficacies of the depot preparations of various agonists, but pharmacodynamic studies have shown comparable suppressive capabilities on estradiol and luteinizing hormone. At present, only monthly goserelin is Food and Drug Administration-approved for the treatment of estrogen receptor-positive, premenopausal metastatic breast cancer in the United States. Luteinizing hormone-releasing hormone agonists have proven to be as effective as surgical oophorectomy in premenopausal advanced breast cancer. They offer similar outcomes compared with tamoxifen, but the endocrine combination appears to be more effective than LH-RH agonists alone. In the adjuvant setting, LH-RH agonists versus no therapy reduce the annual odds of recurrence and death in women aged>50 years with estrogen receptor-positive tumors. Luteinizing hormone-releasing hormone agonists alone or in combination with tamoxifen have shown disease-free survival rates similar to chemotherapy with CMF (cyclophosphamide/methotrexate/5-fluorouracil). Outcomes of chemotherapy with or without LH-RH agonists are comparable, though a few trials favor the combination in young premenopausal women (aged<40 years). Adjuvant LH-RH agonists with or without tamoxifen might be as efficacious as tamoxifen alone

  11. Future possibilities in the prevention of breast cancer: Luteinizing hormone-releasing hormone agonists

    PubMed Central

    Spicer, Darcy V; Pike, Malcolm C

    2000-01-01

    The cyclic production of estrogen and progesterone by the premenopausal ovary accounts for the steep rise in breast cancer risk in premenopausal women. These hormones are breast cell mitogens. By reducing exposure to these ovarian hormones, agonists of luteinizing hormone-releasing hormone (LHRH) given to suppress ovarian function may prove useful in cancer prevention. To prevent deleterious effects of hypoestrogenemia, the addition of low-dose hormone replacement to the LHRH agonist appears necessary. Pilot data with such an approach indicates it is feasible and reduces mammographic densities. PMID:11250719

  12. The peptide growth factor, phytosulfokine, attenuates pattern-triggered immunity.

    PubMed

    Igarashi, Daisuke; Tsuda, Kenichi; Katagiri, Fumiaki

    2012-07-01

    Pattern-triggered immunity (PTI) is triggered by recognition of elicitors called microbe-associated molecular patterns (MAMPs). Although immune responses may provide good protection of plants from pathogen attack, excessive immune responses have negative impacts on plant growth and development. Thus, a good balance between positive and negative effects on the immune signaling network is important for plant fitness. However, little information is known about the molecular mechanisms that are involved in attenuation of PTI. Here, we describe a growth-promoting peptide hormone, phytosulfokine (PSK), as attenuating PTI signaling in Arabidopsis. This research was motivated by the observation that expression of the PSK Receptor 1 (PSKR1) gene was induced by MAMP treatment. Plants homozygous for pskr1 T-DNA insertions showed enhanced defense gene expression and seedling growth inhibition triggered by MAMPs. The pskr1 plants also showed enhanced PTI against the bacterial pathogen Pseudomonas syringae. These results indicate that the PSKR-mediated signaling attenuates immune responses. Tyrosyl protein sulfotransferase (TPST) is an enzyme required for production of the mature sulfated PSK. Like pskr1 mutants, a tpst T-DNA insertion line exhibited enhanced MAMP-triggered seedling growth inhibition, which was suppressed by exogenous application of PSK. Thus, PSK signaling mediated by PSKR1 attenuates PTI but stimulates growth.

  13. A secretagogin locus of the mammalian hypothalamus controls stress hormone release.

    PubMed

    Romanov, Roman A; Alpár, Alán; Zhang, Ming-Dong; Zeisel, Amit; Calas, André; Landry, Marc; Fuszard, Matthew; Shirran, Sally L; Schnell, Robert; Dobolyi, Árpád; Oláh, Márk; Spence, Lauren; Mulder, Jan; Martens, Henrik; Palkovits, Miklós; Uhlen, Mathias; Sitte, Harald H; Botting, Catherine H; Wagner, Ludwig; Linnarsson, Sten; Hökfelt, Tomas; Harkany, Tibor

    2015-01-02

    A hierarchical hormonal cascade along the hypothalamic-pituitary-adrenal axis orchestrates bodily responses to stress. Although corticotropin-releasing hormone (CRH), produced by parvocellular neurons of the hypothalamic paraventricular nucleus (PVN) and released into the portal circulation at the median eminence, is known to prime downstream hormone release, the molecular mechanism regulating phasic CRH release remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagogin's Ca(2+) sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone. Pharmacological tools combined with RNA interference demonstrate that secretagogin's loss of function occludes adrenocorticotropic hormone release from the pituitary and lowers peripheral corticosterone levels in response to acute stress. Cumulatively, these data define a novel secretagogin neuronal locus and molecular axis underpinning stress responsiveness.

  14. A secretagogin locus of the mammalian hypothalamus controls stress hormone release

    PubMed Central

    Romanov, Roman A; Alpár, Alán; Zhang, Ming-Dong; Zeisel, Amit; Calas, André; Landry, Marc; Fuszard, Matthew; Shirran, Sally L; Schnell, Robert; Dobolyi, Árpád; Oláh, Márk; Spence, Lauren; Mulder, Jan; Martens, Henrik; Palkovits, Miklós; Uhlen, Mathias; Sitte, Harald H; Botting, Catherine H; Wagner, Ludwig; Linnarsson, Sten; Hökfelt, Tomas; Harkany, Tibor

    2015-01-01

    A hierarchical hormonal cascade along the hypothalamic-pituitary-adrenal axis orchestrates bodily responses to stress. Although corticotropin-releasing hormone (CRH), produced by parvocellular neurons of the hypothalamic paraventricular nucleus (PVN) and released into the portal circulation at the median eminence, is known to prime downstream hormone release, the molecular mechanism regulating phasic CRH release remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagogin’s Ca2+ sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone. Pharmacological tools combined with RNA interference demonstrate that secretagogin’s loss of function occludes adrenocorticotropic hormone release from the pituitary and lowers peripheral corticosterone levels in response to acute stress. Cumulatively, these data define a novel secretagogin neuronal locus and molecular axis underpinning stress responsiveness. PMID:25430741

  15. Dose-related effects of lauric acid on antropyloroduodenal motility, gastrointestinal hormone release, appetite, and energy intake in healthy men.

    PubMed

    Little, Tanya J; Feltrin, Kate L; Horowitz, Michael; Smout, Andre J P M; Rades, Thomas; Meyer, James H; Pilichiewicz, Amelia N; Wishart, Judith; Feinle-Bisset, Christine

    2005-10-01

    We recently reported that intraduodenal infusion of lauric acid (C12) (0.375 kcal/min, 106 mM) stimulates isolated pyloric pressure waves (IPPWs), inhibits antral and duodenal pressure waves (PWs), stimulates release of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), and suppresses energy intake and that these effects are much greater than those seen in response to isocaloric decanoic acid (C10) infusion. Administration of C12 was, however, associated with nausea, confounding interpretation of the results. The aim of this study was to evaluate the effects of different intraduodenal doses of C12 on antropyloroduodenal (APD) motility, plasma CCK and GLP-1 concentrations, appetite, and energy intake. Thirteen healthy males were studied on 4 days in double-blind, randomized fashion. APD pressures, plasma CCK and GLP-1 concentrations, and appetite perceptions were measured during 90-min ID infusion of C12 at 0.1 (14 mM), 0.2 (28 mM), or 0.4 (56 mM) kcal/min or saline (control; rate 4 ml/min). Energy intake was determined at a buffet meal immediately following infusion. C12 dose-dependently stimulated IPPWs, decreased antral and duodenal motility, and stimulated secretion of CCK and GLP-1 (r > 0.4, P < 0.05 for all). C12 (0.4 kcal/min) suppressed energy intake compared with control, C12 (0.1 kcal/min), and C12 (0.2 kcal/min) (P < 0.05). These effects were observed in the absence of nausea. In conclusion, intraduodenal C12 dose-dependently modulated APD motility and gastrointestinal hormone release in healthy male subjects, whereas effects on energy intake were only apparent with the highest dose infused (0.4 kcal/min), possibly because only at this dose was modulation of APD motility and gastrointestinal hormone secretion sufficient for a suppressant effect on energy intake.

  16. Neonatal imprinting predetermines the sexually dimorphic, estrogen-dependent expression of galanin in luteinizing hormone-releasing hormone neurons.

    PubMed Central

    Merchenthaler, I; Lennard, D E; López, F J; Negro-Vilar, A

    1993-01-01

    The incidence of colocalization of galanin (GAL) in luteinizing hormone-releasing hormone (LHRH) neurons is 4- to 5-fold higher in female than male rats. This fact and the finding that the degree of colocalization parallels estradiol levels during the estrous cycle suggest that GAL is an estrogen-inducible product in a subset of LHRH neurons. To analyze further this paradigm we evaluated the effects of gonadectomy and steroid replacement therapy in male and female rats. Ovariectomy resulted in a significant decrease in the number of cells colocalizing LHRH and GAL, whereas estradiol replacement to such animals restored the incidence of colocalization to that observed in controls. In males, however, estradiol treatment failed to enhance the incidence of colocalization of GAL and LHRH, indicating, therefore, that the colocalization of these peptides is gender-determined. This possibility--i.e., gender-specific determination of LHRH neurons coexpressing GAL--was evaluated by neonatal manipulation of hypothalamic steroid imprinting. As mentioned above, male rats did not respond to estrogen or testosterone by increasing GAL/LHRH colocalization as females did. Neonatally orchidectomized rats, whose hypothalami have not been exposed to testosterone during the critical period, when treated with estrogen in adulthood showed an increase in colocalization of GAL and LHRH similar to that seen in female animals. These observations indicate that the colocalization of LHRH/GAL is neonatally determined by an epigenetic mechanism that involves the testis. In summary, this sex difference in the incidence of colocalization of GAL and LHRH represents a unique aspect of sexual differentiation in that only certain phenotypic characteristics of a certain cellular lineage are dimorphic. The subpopulation of LHRH neurons that also produces GAL represents a portion of the LHRH neuronal system that is sexually differentiated and programed to integrate, under steroidal control, a network of

  17. SHORT PEDF-DERIVED PEPTIDE INHIBITS ANGIOGENESIS AND TUMOR GROWTH

    PubMed Central

    Mirochnik, Yelena; Aurora, Arin; Schulze-Hoepfner, Frank T.; Deabes, Ahmed; Shifrin, Victor; Beckmann, Richard; Polsky, Charles; Volpert, Olga V.

    2010-01-01

    Purpose Pigment epithelial-derived factor (PEDF) is a potent angiogenesis inhibitor with multiple other functions, some of which enhance tumor growth. Our previous studies mapped PEDF anti-angiogenic and pro-survival activities to distinct epitopes. This study was aimed to determine the minimal fragment of PEDF, which maintains anti-angiogenic and anti-tumor efficacy. Experimental Design We analyzed antigenicity, hydrophilicity, and charge distribution of the angioinhibitory epitope (the 34-mer) and designed three peptides covering its C-terminus, P14, P18 and P23. We analyzed their ability to block endothelial cell (EC) chemotaxis and induce apoptosis in vitro and their anti-angiogenic activity in vivo. The selected peptide was tested for the anti-tumor activity against mildly aggressive xenografted prostate carcinoma and highly aggressive renal cell carcinoma. To verify that P18 acts in the same manner as PEDF, we used immunohistochemistry to measure PEDF targets, VEGFR2 and CD95L expression in P18-treated vasculature. Results P14 and P18 blocked endothelial cell chemotaxis; P18 and P23 induced apoptosis. P18 showed the highest IC50 and blocked angiogenesis in vivo: P23 was inactive and P14 was pro-angiogenic. P18 increased the production of CD95L and reduced the expression of VEGFR-2 by the endothelial cells in vivo. In tumor studies, P18 was more effective in blocking the angiogenesis and growth of the prostate cancer then parental 34-mer; in the renal cell carcinoma P18 strongly decreased angiogenesis and halted the progression of established tumors. Conclusions P18 is a novel and potent anti-angiogenic biotherapeutic agent, which has potential to be developed for the treatment of prostate and renal cancer. PMID:19223494

  18. Detecting peptidic drugs, drug candidates and analogs in sports doping: current status and future directions.

    PubMed

    Thevis, Mario; Thomas, Andreas; Schänzer, Wilhelm

    2014-12-01

    With the growing availability of mature systems and strategies in biotechnology and the continuously expanding knowledge of cellular processes and involved biomolecules, human sports drug testing has become a considerably complex field in the arena of analytical chemistry. Proving the exogenous origin of peptidic drugs and respective analogs at lowest concentration levels in biological specimens (commonly blood, serum and urine) of rather limited volume is required to pursue an action against cheating athletes. Therefore, approaches employing chromatographic-mass spectrometric, electrophoretic, immunological and combined test methods have been required and developed. These allow detecting the misuse of peptidic compounds of lower (such as growth hormone-releasing peptides, ARA-290, TB-500, AOD-9604, CJC-1295, desmopressin, luteinizing hormone-releasing hormones, synacthen, etc.), intermediate (e.g., insulins, IGF-1 and analogs, 'full-length' mechano growth factor, growth hormone, chorionic gonadotropin, erythropoietin, etc.) and higher (e.g., stamulumab) molecular mass with desired specificity and sensitivity. A gap between the technically possible detection and the day-to-day analytical practice, however, still needs to be closed.

  19. Active immunization to luteinizing hormone releasing hormone to inhibit the induction of mammary tumors in the rat

    SciTech Connect

    Ravdin, P.M.; Jordan, V.C.

    1988-01-01

    Immunization of female rats with a bovine serum albumin-luteinizing hormone releasing hormone conjugate results in suppression of dimethylbenzanthracene mammary tumor incidence. Tumor incidence was 1.3, and 1.29 tumors per rat in bovine serum albumin alone (n = 10) and unimmunized (n = 18) control groups, but no tumors were found in the bovine serum albumin-luteinizing hormone releasing hormone conjugate immunized animals (n = 10). In a second experiment immunization with bovine serum albumin-luteinizing hormone releasing hormone conjugates reduced tumor incidence to 0.3 tumors per rat (n = 10) from the 1.2 tumors per animal seen in the control animals (n = 10) immunized with bovine serum albumin alone. Bovine serum albumin-luteinizing hormone immunization caused the production of anti-LHRH antibodies, an interruption of estrous cycles, lowered serum estradiol and progesterone levels, and atrophy of the ovaries and uteri. Immunization BSA-hormone conjugates is a novel anti-tumor strategy.

  20. Suprachiasmatic nuclei may regulate the rhythm of leptin hormone release in Syrian hamsters (Mesocricetus auratus).

    PubMed

    Karakas, Alper; Gündüz, Bülent

    2006-01-01

    The suprachiasmatic nuclei (SCN) generate the circadian rhythm of many hormones. The hormone leptin is a metabolic signal that informs the brain about fat and energy stores of the body. We investigated whether the rhythm of leptin hormone release in Syrian hamsters is directly controlled by the SCN. Three experiments were performed: in the first, hamsters were SCN-lesioned; in the second, hamsters were exposed to different feeding regimes; and in the third, hamsters were adrenalectomized and implanted with cortisol capsules to maintain constant glucocorticoid release. Blood samples were collected before and after the experiments at different clock times and examined for leptin levels by enzyme-linked immunosorbant assay (ELISA). Different feeding regimes and constant glucocorticoid release did not alter the rhythm of leptin release; whereas, SCN lesions abolished the rhythm. The results of the present study suggest the rhythm in leptin release in Syrian hamsters may be controlled by the SCN.

  1. Luteinizing hormone releasing factor in rat hypophysial portal blood collected during electrical stimulation of the hypothalamus

    PubMed Central

    Harris, G. W.; Ruf, K. B.

    1970-01-01

    1. Ovulation was induced in Nembutal-blocked pro-oestrous rats by electrical stimulation of the hypothalamus. 2. The same type of electrical stimulation was applied during the collection of hypophysial portal blood. 3. Pooled hypophysial portal plasma from donors in pro-oestrus, oestrus and met-oestrus was assayed for ovarian ascorbic acid depleting (OAAD) activity. 4. Electrical stimulation of the hypothalamus increased the OAAD activity, believed to be due to luteinizing hormone releasing factor (LRF), in pro-oestrus and met-oestrus, but not in oestrus. 5. It is concluded that the hypothalamic nerve fibres responsible for releasing LRF into the hypophysial portal vessels are depleted of their store of this releasing factor, or are refractory to electrical stimulation, during oestrus. PMID:5499765

  2. A simple pharmacokinetic model linking plasma progesterone concentrations with the hormone released from bovine intravaginal inserts.

    PubMed

    Mariano, R N; Turino, L N; Cabrera, M I; Scándolo, D E; Maciel, M G; Grau, R J A

    2010-10-01

    On the basis of pharmacokinetic modeling, this study provides some insights into predicting in vivo plasma progesterone concentrations when using bovine intravaginal inserts for systemic progesterone delivery. More significantly, this contribution is the first attempt to build a simple pharmacokinetic model that links plasma progesterone concentrations with the hormone released from bovine intravaginal inserts. After evaluating three rival pharmacokinetic models and considering some phenomena involved in the intravaginal administration of progesterone, a primary pharmacokinetic model having a good data fitting capability with only two adjustable parameters is proposed to the above mentioned task. Kinetic parameters are given for lactating Holstein dairy cows with two levels of daily milk yields; and non-pregnant, non-lactating Holstein-Friesian cattle. Model predictions indicate the occurrence of a preferential distribution of the intravaginally administered progesterone dose through a first uterine pass effect.

  3. Migration of luteinizing hormone-releasing hormone (LHRH) neurons in early human embryos.

    PubMed

    Schwanzel-Fukuda, M; Crossin, K L; Pfaff, D W; Bouloux, P M; Hardelin, J P; Petit, C

    1996-03-11

    Luteinizing hormone-releasing hormone (LHRH) neurons originate in the epithelium of the medial olfactory pit and migrate from the nose into the forebrain along nerve fibers rich in neural cell adhesion molecule (N-CAM). The present study examined the ontogenesis of LHRH neurons in early human embryos and found a similar pattern of development of these cells. Luteinizing hormone-releasing hormone immunoreactivity was detected in the epithelium of the medial olfactory pit and in cells associated with the terminal-vomeronasal nerves at 42 (but not 28-32) days of gestation. The migration route of these cells was examined with antibodies to N-CAM and antibodies to polysialic acid (PSA-N-CAM), which is present on N-CAM at certain stages of development. Neural cell adhesion molecule immunoreactivity was present in a population of cells in the olfactory placode of the earliest embryos examined (28-32 days) and later (42 and 46 days) throughout the migration route. The PSA-N-CAM immunoreactivity was not detected until 42 days and was present in a more limited distribution in nerve fibers streaming from the olfactory placode and along the caudal part of the migration route below the forebrain. Previous studies have indicated that the highly sialated form of N-CAM is less adhesive. The PSA-N-CAM may therefore facilitate the migration of these cells by lessening the adhesion between the fascicles that make up the migration route, expediting the passage of cords of LHRH cells between the nerve fibers as these cells move toward the brain.

  4. Comparative Effect of ACTH and Related Peptides on Proliferation and Growth of Rat Adrenal Gland

    PubMed Central

    Lotfi, Claudimara Ferini Pacicco; de Mendonca, Pedro O. R.

    2016-01-01

    Pro-opiomelanocortin (POMC) is a polypeptide precursor known to yield biologically active peptides related to a range of functions. These active peptides include the adrenocorticotropic hormone (ACTH), which is essential for maintenance of adrenal growth and steroidogenesis, and the alpha-melanocyte stimulation hormone, which plays a key role in energy homeostasis. However, the role of the highly conserved N-terminal region of POMC peptide fragments has begun to be unraveled only recently. Here, we review the cascade of events involved in regulation of proliferation and growth of murine adrenal cortex triggered by ACTH and other POMC-derived peptides. Key findings regarding signaling pathways and modulation of genes and proteins required for the regulation of adrenal growth are summarized. We have outlined the known mechanisms as well as future challenges for research on the regulation of adrenal proliferation and growth triggered by these peptides. PMID:27242663

  5. Homologous down-regulation of growth hormone-releasing hormone receptor messenger ribonucleic acid levels.

    PubMed

    Aleppo, G; Moskal, S F; De Grandis, P A; Kineman, R D; Frohman, L A

    1997-03-01

    Repeated stimulation of pituitary cell cultures with GH-releasing hormone (GHRH) results in diminished responsiveness, a phenomenon referred to as homologous desensitization. One component of GHRH-induced desensitization is a reduction in GHRH-binding sites, which is reflected by the decreased ability of GHRH to stimulate a rise in intracellular cAMP. In the present study, we sought to determine if homologous down-regulation of GHRH receptor number is due to a decrease in GHRH receptor synthesis. To this end, we developed and validated a quantitative RT-PCR assay system that was capable of assessing differences in GHRH-R messenger RNA (mRNA) levels in total RNA samples obtained from rat pituitary cell cultures. Treatment of pituitary cells with GHRH, for as little as 4 h, resulted in a dose-dependent decrease in GHRH-R mRNA levels. The maximum effect was observed with 0.1 and 1 nM GHRH, which reduced GHRH-R mRNA levels to 49 +/- 4% (mean +/- SEM) and 54 +/- 11% of control values, respectively (n = three separate experiments; P < 0.05). Accompanying the decline in GHRH-R mRNA levels was a rise in GH release; reaching 320 +/- 31% of control values (P < 0.01). Because of the possibility that the rise in medium GH level is the primary regulator of GHRH-R mRNA, we pretreated pituitary cultures for 4 h with GH to achieve a concentration comparable with that induced by a maximal stimulation with GHRH (8 micrograms GH/ml medium). Following pretreatment, cultures were stimulated for 15 min with GHRH and intracellular cAMP accumulation was measured by RIA. GH pretreatment did not impair the ability of GHRH to induce a rise in cAMP concentrations. However, as anticipated, GHRH pretreatment (10 nM) significantly reduced subsequent GHRH-stimulated cAMP to 46% of untreated controls. These data suggest that GHRH, but not GH, directly reduces GHRH-R mRNA levels. To determine whether this effect was mediated through cAMP, cultures were treated with forskolin, a direct stimulator of adenylate cyclase. Forskolin (10 microM) significantly reduced GHRH-R mRNA concentrations (37 +/- 6% of control values) indicating that GHRH acts through the cAMP-second messenger system cascade to regulate GHRH-R mRNA. The somatostatin analogue, octreotide (10 nM), which has been previously reported to decrease adenylate cyclase activity, did not affect GHRH-R mRNA levels. Taken together, these results indicate that GHRH inhibits the production of its own receptor by a receptor-mediated, cAMP-dependent reduction of GHRH-R mRNA accumulation.

  6. Treatment of nitrosamine-induced pancreatic tumors in hamsters with analogs of somatostatin and luteinizing hormone-releasing hormone

    SciTech Connect

    Paz-Bouza, J.I.; Redding, T.W.; Schally, A.V.

    1987-02-01

    Pancreatic ductal adenocarcinoma was induced in female Syrian golden hamsters by injecting N-nitrosobis(2-oxopropyl)amine (BOP) once a week at a dose of 10 mg per kg of body weight for 18 weeks. Hamsters were then treated with somatostatin analog (RC-160) or with (6-D-tryptophan)luteinizing hormone-releasing hormone ((D-Trp/sup 6/)LH-RH) delayed delivery systems. After 18 weeks of BOP administration, the hamsters were divided into three groups of 10-20 animals each. Group I consisted of untreated controls, group II was injected with RC-160, and group III was injected with (D-Trp/sub 2/)LH-RH. A striking decrease in tumor weight and volume was obtained in animals treated with (D-Trp/sup 6/)LH-RH or with the somatostatin analog RC-160. After 45 days of treatment with either analog, the survival rate was significantly higher in groups II and III (70%), as compared with the control group (35%). The studies, done by light microscopy, high-resolution microscopy, and electron microscopy, showed a decrease in the total number of cancer cells and changes in the epithelium, connective tissue, and cellular organelles in groups II and III treated with the hypothalamic analogs as compared to controls. These results in female hamsters with induced ductal pancreatic tumors confirm and extend the authors findings, obtained in male animals with transplanted tumors, that (D-Trp/sub 6/)LH-RH and somatostatin analogs inhibit the growth of pancreatic cancers.

  7. Targeted Proapoptotic Peptides Depleting Adipose Stromal Cells Inhibit Tumor Growth

    PubMed Central

    Daquinag, Alexes C; Tseng, Chieh; Zhang, Yan; Amaya-Manzanares, Felipe; Florez, Fernando; Dadbin, Ali; Zhang, Tao; Kolonin, Mikhail G

    2016-01-01

    Progression of many cancers is associated with tumor infiltration by mesenchymal stromal cells (MSC). Adipose stromal cells (ASC) are MSC that serve as adipocyte progenitors and endothelium-supporting cells in white adipose tissue (WAT). Clinical and animal model studies indicate that ASC mobilized from WAT are recruited by tumors. Direct evidence for ASC function in tumor microenvironment has been lacking due to unavailability of approaches to specifically inactivate these cells. Here, we investigate the effects of a proteolysis-resistant targeted hunter-killer peptide D-WAT composed of a cyclic domain CSWKYWFGEC homing to ASC and of a proapoptotic domain KLAKLAK2. Using mouse bone marrow transplantation models, we show that D-WAT treatment specifically depletes tumor stromal and perivascular cells without directly killing malignant cells or tumor-infiltrating leukocytes. In several mouse carcinoma models, targeted ASC cytoablation reduced tumor vascularity and cell proliferation resulting in hemorrhaging, necrosis, and suppressed tumor growth. We also validated a D-WAT derivative with a proapoptotic domain KFAKFAK2 that was found to have an improved cytoablative activity. Our results for the first time demonstrate that ASC, recruited as a component of tumor microenvironment, support cancer progression. We propose that drugs targeting ASC can be developed as a combination therapy complementing conventional cancer treatments. PMID:26316391

  8. Suppression of tumor growth by novel peptides homing to tumor-derived new blood vessels.

    PubMed

    Asai, Tomohiro; Nagatsuka, Mayumi; Kuromi, Koichi; Yamakawa, Satoru; Kurohane, Kohta; Ogino, Koichi; Tanaka, Michinori; Taki, Takao; Oku, Naoto

    2002-01-16

    Novel peptides homing to angiogenic vessels were recently isolated from a phage-displayed random pentadecapeptide library. One of the isolated peptides, ASSSYPLIHWRPWAR, significantly suppressed the migration of VEGF-stimulated human umbilical vein endothelial cells. Dendoric ASSSYPLIHWRPWAR-peptide suppressed the formation of new blood vessels in dorsal air sac model mice. Furthermore, ASSSYPLIHWRPWAR-peptide and the fragment peptides containing WRP, which is revealed to be an epitope sequence, significantly suppressed the tumor growth, although 15-mer shuffled peptide derived from ASSSYPLIHWRPWAR and pentapeptides with alanine substitution of each residue of WRP did not. Taken together, ASSSYPLIHWRPWAR-peptide may cause tumor dormancy through inhibition of angiogenesis, and the WRP sequence may be the minimal and essential sequence for this activity.

  9. Supplementation of oligofructose, but not sucralose, decreases high-fat diet induced body weight gain in mice independent of gustducin-mediated gut hormone release.

    PubMed

    Steensels, Sandra; Cools, Leen; Avau, Bert; Vancleef, Laurien; Farré, Ricard; Verbeke, Kristin; Depoortere, Inge

    2017-03-01

    Enteroendocrine cells sense nutrients through taste receptors similar to those on the tongue. Sweet and fatty acid taste receptors (FFAR) coupled to the gustatory G-protein, gustducin, on enteroendocrine cells play a role in gut hormone release. We studied if supplementation of artificial (sucralose) or prebiotic (oligofructose; OFS) sweeteners target gustducin-mediated signaling pathways to alter gut hormone release and reduce obesity-associated disorders. Wild-type (WT) and α-gustducin knockout (α-gust(-/-) ) mice were fed a high-fat diet and gavaged once daily (8 wk) with water or equisweet concentrations of sweeteners. OFS but not sucralose decreased body weight gain (-19 ± 3%, p < 0.01), fat pad mass (-55 ± 6%, p < 0.001), and insulin resistance (-39 ± 5%, p < 0.001) independent of α-gustducin. Neither sweetener improved glucose intolerance, while solely OFS improved the disturbed colonic permeability. OFS decreased (-65 ± 8%, p < 0.001) plasma glucagon-like peptide 1 (GLP-1) but not ghrelin and peptide YY (PYY) levels in WT mice. Cecal acetate and butyrate levels were reduced by OFS in both genotypes suggesting enhanced uptake of SCFAs that may target FFAR2 (upregulated expression) in adipose tissue. OFS, but not sucralose, reduced body weight gain and decreased intestinal permeability, but not glucose intolerance. Effects were not mediated by altered gut hormone levels or gustducin-mediated signaling. Artificial sweeteners do not affect gut hormone levels and are metabolically inert in mice on a high-fat diet. In contrast, prebiotic oligosaccharides (OFS) prevent body weight gain but not glucose intolerance. Alterations in sweet and short-chain fatty acid receptors (FFAR) (studied in WT and α-gust(-/-) mice) that regulate gut hormone levels are not mandatory for the positive effects of OFS. Enhanced uptake of SCFAs may favor interaction with FFAR2/3 on adipose tissue to induce weight loss. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Self-assembling peptide amphiphiles and related methods for growth factor delivery

    DOEpatents

    Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

    2009-06-09

    Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

  11. Self-assembling peptide amphiphiles and related methods for growth factor delivery

    DOEpatents

    Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

    2012-03-20

    Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

  12. Self-assembling peptide amphiphiles and related methods for growth factor delivery

    DOEpatents

    Stupp, Samuel I; Donners, Jack J.J.M.; Silva, Gabriel A; Behanna, Heather A; Anthony, Shawn G

    2013-11-12

    Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

  13. Luteinizing Hormone-Releasing Hormone Enhances T Cell Recovery following Allogeneic Bone Marrow Transplantation1

    PubMed Central

    Goldberg, Gabrielle L.; King, Christopher G.; Nejat, Rebecca A.; Suh, David Y.; Smith, Odette M.; Bretz, Jamison C.; Samstein, Robert M.; Dudakov, Jarrod A.; Chidgey, Ann P.; Chen-Kiang, Selina; Boyd, Richard L.; van den Brink, Marcel R. M.

    2009-01-01

    Posttransplant immunodeficiency, specifically a lack of T cell reconstitution, is a major complication of allogeneic bone marrow transplantation. This immunosuppression results in an increase in morbidity and mortality from infections and very likely contributes to relapse. In this study, we demonstrate that sex steroid ablation using leuprolide acetate, a luteinizing hormone-releasing hormone agonist (LHRHa), increases the number of lymphoid and myeloid progenitor cells in the bone marrow and developing thymocytes in the thymus. Although few differences are observed in the peripheral myeloid compartments, the enhanced thymic reconstitution following LHRHa treatment and allogeneic bone marrow transplantation leads to enhanced peripheral T cell recovery, predominantly in the naive T cell compartment. This results in an increase in T cell function in vivo and in vitro. Graft-versus-host-disease is not exacerbated by LHRHa treatment and graft-versus-tumor activity is maintained. Because LHRHa allows for reversible (and temporary) sex steroid ablation, has a strong safety profile, and has been clinically approved for diseases such as prostate and breast cancer, this drug treatment represents a novel therapeutic approach to reversal of thymic atrophy and enhancement of immunity following immunosuppression. PMID:19380833

  14. Comparison of the effects of human and chicken ghrelin on chicken ovarian hormone release.

    PubMed

    Sirotkin, Alexander V; Harrath, Abdel Halim; Grossmann, Roland

    2016-11-01

    The aim of the present experiments was to examine the species-specific and cell-specific effects of ghrelin on chicken ovarian hormone release. For this purpose, we compared the effects of chicken and human ghrelin on the release of estradiol (E), testosterone (T), progesterone (P) and arginine-vasotocin (AVT) by cultured fragments of chicken ovarian follicles and on the release of T and AVT by cultured ovarian granulosa cells. In cultured chicken ovarian fragments, both human and chicken ghrelin promoted E release. T output was stimulated by chicken ghrelin but not by human ghrelin. No effect of either human or chicken ghrelin on P release was observed. Human ghrelin promoted but chicken ghrelin suppressed AVT release by chicken ovarian fragments. In cultured ovarian granulosa cells, human ghrelin inhibited while chicken ghrelin stimulated T release. Both human and chicken ghrelin suppressed AVT output by chicken granulosa cells. These data confirm the involvement of ghrelin in the control of ovarian secretory activity and demonstrate that the effect of ghrelin is species-specific. The similarity of avian ghrelin on avian ovarian granulosa cells and ovarian fragments (containing both granulosa and theca cells) suggests that ghrelin can influence chicken ovarian hormones primarily by acting on granulosa cells.

  15. Luteinizing hormone--releasing hormone agonists: a quick reference for prevalence rates of potential adverse effects.

    PubMed

    Walker, Lauren M; Tran, Susan; Robinson, John W

    2013-12-01

    Men with prostate cancer (PCa) frequently undergo androgen deprivation therapy (ADT), typically in the form of a depot injection of luteinizing hormone-releasing hormone agonists (LHRHa). LHRHa are associated with many adverse effects (eg, hot flashes, sexual dysfunction, loss of muscle mass, osteopenia, metabolic syndrome), which drastically impact patient quality of life. This literature review, which includes a comprehensive table documenting prevalence rates, provides a quick reference for health care professionals involved in the care of men undergoing ADT with LHRHa. Primary sources were acquired from PubMed using the search terms "androgen deprivation therapy" and each potentially adverse effect (eg, "androgen deprivation therapy and hot flashes"). Commonly cited review articles were also examined for citations of original studies containing prevalence rates. More than 270 articles were reviewed. In contrast to many existing reviews, rates are cited exclusively from original sources. The prevalence rates, obtained from original sources, suggest that more than half of documented adverse effects are experienced by as many as 40% or more of patients. A critique of the literature is also provided. Although there is a vast literature of both original and review articles on specific adverse effects of LHRHa, the quality of research on prevalence rates for some adverse effects is subpar. Many review articles contain inaccuracies and do not cite original sources. The table of prevalence rates will serve as a quick reference for health care providers when counseling patients and will aid in the development of evidence-based patient education materials.

  16. Inhibition of breast cancer growth and metastasis by a biomimetic peptide.

    PubMed

    Lee, Esak; Lee, Seung Jae; Koskimaki, Jacob E; Han, Zheyi; Pandey, Niranjan B; Popel, Aleksander S

    2014-11-20

    Metastasis is the main cause of mortality in cancer patients. Though there are many anti-cancer drugs targeting primary tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression, particularly, lymphangiogenesis is pivotal for metastasis in breast cancer. Here we report that a novel collagen IV derived biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis. The peptide inhibits blood and lymphatic endothelial cell viability, migration, adhesion, and tube formation by targeting IGF1R and Met signals. The peptide blocks MDA-MB-231 tumor growth by inhibiting tumor angiogenesis in vivo. Moreover, the peptide inhibits lymphangiogenesis in primary tumors. MDA-MB-231 tumor conditioned media (TCM) was employed to accelerate spontaneous metastasis in tumor xenografts, and the anti-metastatic activity of the peptide was tested in this model. The peptide prevents metastasis to the lungs and lymph nodes by inhibiting TCM-induced lymphangiogenesis and angiogenesis in the pre-metastatic organs. In summary, a novel biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis in the pre-metastatic organs as well as primary tumors.

  17. Inhibition of breast cancer growth and metastasis by a biomimetic peptide

    PubMed Central

    Lee, Esak; Lee, Seung Jae; Koskimaki, Jacob E.; Han, Zheyi; Pandey, Niranjan B.; Popel, Aleksander S.

    2014-01-01

    Metastasis is the main cause of mortality in cancer patients. Though there are many anti-cancer drugs targeting primary tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression, particularly, lymphangiogenesis is pivotal for metastasis in breast cancer. Here we report that a novel collagen IV derived biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis. The peptide inhibits blood and lymphatic endothelial cell viability, migration, adhesion, and tube formation by targeting IGF1R and Met signals. The peptide blocks MDA-MB-231 tumor growth by inhibiting tumor angiogenesis in vivo. Moreover, the peptide inhibits lymphangiogenesis in primary tumors. MDA-MB-231 tumor conditioned media (TCM) was employed to accelerate spontaneous metastasis in tumor xenografts, and the anti-metastatic activity of the peptide was tested in this model. The peptide prevents metastasis to the lungs and lymph nodes by inhibiting TCM-induced lymphangiogenesis and angiogenesis in the pre-metastatic organs. In summary, a novel biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis in the pre-metastatic organs as well as primary tumors. PMID:25409905

  18. Characterization of antibodies to synthetic nerve growth factor (NGF) and proNGF peptides.

    PubMed

    Ebendal, T; Persson, H; Larhammar, D; Lundströmer, K; Olson, L

    1989-03-01

    Sequence data for the mature nerve growth factor (NGF) protein and its precursor are available from molecular cloning of the NGF gene in several species, including mice, humans, rats, and chickens. Hydrophilicity analysis of the predicted rat and chicken prepro-NGF was carried out to locate putative antigenic determinants. Eight peptides were selected and synthesized based on hydrophilicity profiles. Two peptides represent sequences in the rat (and mouse) pro-NGF, one peptide (our peptide P3) represents a highly conserved region of the mature NGF protein (identical in humans, mice, rats, and chickens), two peptides are specific for the mature chicken NGF, and the remaining three peptides are specific for the mature rat NGF (each with only one amino acid substitution compared with corresponding segments of the mouse NGF). For immunization, the peptides were conjugated to keyhold limpet hemocyanin and used to produce antisera in rabbits. After bleeding, peptide-specific antibodies were purified on affinity columns prepared by coupling each of the synthetic peptides. The different peptide antisera and affinity-purified antibodies then were characterized by enzyme-linked immunoassay (ELISA) and immunohistochemistry of the male mouse submandibular gland, a rich exocrine source of NGF. ELISA analysis showed that all peptide antisera bound two to four orders of magnitude better than normal rabbit serum to a coat of their proper peptide. The higher binding was retained by the purified peptide antibodies compared with normal rabbit immunoglobulin. Specific tests, in which one peptide antiserum was checked against different peptide coats in the ELISA, also showed two to four orders of magnitude higher binding of antibodies to the proper synthetic peptide. The peptide antibodies also were tested for their ability to bind to native mouse beta NGF coated to the immunoplates. Only antibodies raised to the conserved P3 peptide recognized native NGF to an extent similar to that

  19. [Inhibition of tumor growth by a peptide fusion protein binding to vascular endothelial growth factor receptor Flt-1].

    PubMed

    Lei, Hetian; Shou, Chengchao; Wu, Jian; Liu, Xiaoying; He, Luowen; Liu, Meisheng; Guo, Qi; Jiang, Beihai

    2002-10-10

    Investigating the bio-activities of peptides selected from phage display peptide library with vascular endothelial growth factor receptor Flt-1. Activities of DHFR-F56/F90 binding to human ubilial vein endothelial cells were detected by immunocytochemistry, and the activity of antiangiogenesis was determined with chick embryo chorioallantoric membrane (CAM) assay. Balb/c nude mice were used as model to detect the activity of DHFR-F56/F90 on inhibiting tumor growth, and immunohistochemistry was employed to determine the localization of the DHFR-F56/F90 in tumor. DHFR-F56/F90 can bind to HUVEC, and DHFR-F56 inhibite angiogenesis in CAM. Meanwhile DHFR-F56 can bind with tumor cells, induce tumor necrosis and inhibit tumor growth in vivo. The peptide F56 is an effective antagonist of VEGF binding to Flt-1 and has a potent utility in antiangiogenesis and inhibiting tumor growth.

  20. Somatostatin analogs as adjuncts to agonists of luteinizing hormone-releasing hormone in the treatment of experimental prostate cancer.

    PubMed Central

    Schally, A V; Redding, T W

    1987-01-01

    The combination of a long-acting delivery system for the agonist [D-Trp6]luteinizing hormone-releasing hormone ([D-Trp6]LH-RH) with modern somatostatin analogs was studied in the Dunning R-3327H rat prostate cancer model. Microcapsules of [D-Trp6]LH-RH releasing 25 micrograms/day were injected once a month. In the first experiment the adjunct was the somatostatin analog D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2 (RC-121), administered at a dose of 2.5 micrograms twice a day, and the therapy was continued for 70 days. Tumor volume was significantly decreased by [D-Trp6]LH-RH microcapsules or RC-121 given alone. The combination of microcapsules and analog RC-121 caused a greater inhibition of tumor growth than the single agents. Similar effects were seen when the percent increase in the tumor volume was examined. The inhibition of tumor growth caused by the [D-Trp6]LH-RH microcapsules was greater than that caused by RC-121. The combination of the two agents was again the most effective, resulting in the smallest increase in tumor volume. Tumor weights were much lower in the groups treated with microcapsules or RC-121 alone than in controls. The lowest tumor weights were obtained in the group that received the combination of [D-Trp6]LH-RH microcapsules and RC-121. Similar results were obtained in the second experiment, in which the animals were treated for a period of 83 days with microcapsules containing the somatostatin analog D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 (RC-160) that released 5 micrograms/day and were injected twice a month alone or in combination with microcapsules of [D-Trp6]LH-RH. Microcapsules of analog RC-160 given alone significantly decreased tumor growth as measured by the final tumor volume, the percentage change from the initial tumor volume, and the reduction in tumor weight. The inhibition of tumor growth induced by [D-Trp6]LH-RH microcapsules was greater than that caused by RC-160. The most striking decrease in tumor weight and volume was

  1. Glucose absorption, hormonal release and hepatic metabolism after guar gum ingestion

    NASA Technical Reports Server (NTRS)

    Simoes Nunes, C.; Malmlof, K.

    1992-01-01

    Six non-anaesthetized Large White pigs (mean body weight 59 +/- 1.7 kg) were fitted with permanent catheters in the portal vein, the brachiocephalic artery and the right hepatic vein and with electromagnetic flow probes around the portal vein and the hepatic artery. The animals were provided a basal none-fibre diet (diet A) alone or together with 6% guar gum (diet B) or 15% purified cellulose (diet C). The diets were given for 1 week and according to a replicated 3 x 3 latin-square design. On the last day of each adaptation period test meals of 800 g were given prior to blood sampling. The sampling was continued for 8 h. Guar gum strongly reduced the glucose absorption as well as the insulin, gastric inhibitory polypeptide (GIP) and insulin-like growth factor-1 (IGF-1) production. However, the reduction in peripheral blood insulin levels caused by guar gum was not associated with a change in hepatic insulin extraction. IGF-1 appeared to be strongly produced by the gut. The liver had a net uptake of the peptide. Ingestion of guar gum increased the hepatic extraction coefficient of gut produced IGF-1. Guar gum ingestion also appeared to decrease pancreatic glucagon secretion. Cellulose at the level consumed had very little effect on the parameters considered. It is suggested that the modulation of intestinal mechanisms by guar gum was sufficient to mediate the latter internal metabolic effects.

  2. Glucose absorption, hormonal release and hepatic metabolism after guar gum ingestion

    NASA Technical Reports Server (NTRS)

    Simoes Nunes, C.; Malmlof, K.

    1992-01-01

    Six non-anaesthetized Large White pigs (mean body weight 59 +/- 1.7 kg) were fitted with permanent catheters in the portal vein, the brachiocephalic artery and the right hepatic vein and with electromagnetic flow probes around the portal vein and the hepatic artery. The animals were provided a basal none-fibre diet (diet A) alone or together with 6% guar gum (diet B) or 15% purified cellulose (diet C). The diets were given for 1 week and according to a replicated 3 x 3 latin-square design. On the last day of each adaptation period test meals of 800 g were given prior to blood sampling. The sampling was continued for 8 h. Guar gum strongly reduced the glucose absorption as well as the insulin, gastric inhibitory polypeptide (GIP) and insulin-like growth factor-1 (IGF-1) production. However, the reduction in peripheral blood insulin levels caused by guar gum was not associated with a change in hepatic insulin extraction. IGF-1 appeared to be strongly produced by the gut. The liver had a net uptake of the peptide. Ingestion of guar gum increased the hepatic extraction coefficient of gut produced IGF-1. Guar gum ingestion also appeared to decrease pancreatic glucagon secretion. Cellulose at the level consumed had very little effect on the parameters considered. It is suggested that the modulation of intestinal mechanisms by guar gum was sufficient to mediate the latter internal metabolic effects.

  3. Voluntary wheel running modulates glutamate receptor subunit gene expression and stress hormone release in Lewis rats.

    PubMed

    Makatsori, A; Duncko, R; Schwendt, M; Moncek, F; Johansson, B B; Jezova, D

    2003-07-01

    Lewis rats that are known to be addiction-prone, develop compulsive running if they have access to running wheels. The present experiments were aimed 1) to evaluate the activation of stress systems following chronic and acute voluntary wheel running in Lewis rats by measurement of hormone release and gene expression of neuropeptides related to hypothalamic-pituitary-adrenocortical (HPA) axis activity and 2) to test the hypothesis that wheel running as a combined model of addictive behavior and stress exposure is associated with modulation of ionotropic glutamate receptor subunits in the ventral tegmental area. Voluntary running for three weeks but not for one night resulted in a rise in plasma corticosterone and adrenocorticotropic hormone (ACTH) levels (p<0.05) compared to those in control rats. Principal component analysis revealed the relation between POMC gene expression in the intermediate pituitary and running rate. Acute exposure of animals to voluntary wheel running induced a significant decrease in alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor GluR1 subunit mRNA levels (p<0.01), while repeated voluntary physical activity increased levels of GluR1 mRNA in the ventral tegmentum (p<0.05). Neither acute nor chronic wheel running influenced N-methyl-D-aspartate (NMDA) receptor subunit NR1 mRNA levels in the ventral tegmental area. Thus, the present study revealed changes in AMPA receptor subunit gene expression in a reward-related brain structure as well as an activation of HPA axis in response to compulsive wheel running in Lewis rats. It may be suggested that hormones of HPA axis and glutamate receptors belong to the factors that substantiate higher vulnerability to addictive behavior.

  4. Gonadotropin hormone releasing hormone agonists alter prefrontal function during verbal encoding in young women.

    PubMed

    Craig, Michael C; Fletcher, Paul C; Daly, Eileen M; Rymer, Janice; Cutter, William J; Brammer, Mick; Giampietro, Vincent; Wickham, Harvey; Maki, Pauline M; Murphy, Declan G M

    2007-01-01

    Gonadotropin hormone releasing hormone agonists (GnRHa) are commonly used in clinical practice to suppress gonadal hormone production in the management of various gynaecological conditions and as a treatment for advanced breast and prostate cancer. Animal and human behavioural studies suggest that GnRHa may also have significant effects on memory. However, despite the widespread use of GnRHa, the underlying brain networks and/or stages of memory processing that might be modulated by GnRHa remain poorly understood. We used event-related functional magnetic resonance imaging to examine the effect of GnRHa on verbal encoding and retrieval. Neuroimaging outcomes from 15 premenopausal healthy women were assessed at baseline and 8 weeks after Gonadotrophin Releasing Hormone analogue (GnRHa) treatment. Fifteen matched wait-listed volunteers served as the control group and were assessed at similar intervals during the late follicular phase of the menstrual cycle. GnRHa was associated with changes in brain response during memory encoding but not retrieval. Specifically, GnRHa administration led to a change in the typical pattern of prefrontal activation during successful encoding, with decreased activation in left prefrontal cortex, anterior cingulate, and medial frontal gyrus. Our study suggests that the memory difficulties reported by some women following GnRHa, and possibly at other times of acute ovarian hormone withdrawal (e.g. following surgical menopause and postpartum), may have a clear neurobiological basis; one that manifest during encoding of words and that is evident in decreased activation in prefrontal regions known to sub-serve deep processing of to-be-learned words.

  5. Efficacy of switching therapy of luteinizing hormone-releasing hormone analogue for advanced prostate cancer.

    PubMed

    Shen, Yuan-Chi; Kang, Chih-Hsiung; Chiang, Po-Hui

    2016-11-01

    This study was conducted to determine the efficacy of switching therapy with a second-line luteinizing hormone-releasing hormone (LHRH) analogue after prostate-specific antigen (PSA) progression for advanced prostate cancer. We enrolled 200 patients, from December 2005 to September 2013, with nodal positive, metastatic prostate cancer or disease progression after definite treatment receiving continuous LHRH analogue therapy with monthly depot leuprorelin(sc) acetate 3.75 mg/vial (LA) or goserelin acetate(sc) 3.6 mg/vial (GA). If the patients had castration-resistant prostate cancer, the treatment choice of switching therapy (from LA to GA or from GA to LA) prior to starting chemotherapy was given. The LH, testosterone level, and PSA change were recorded. The records showed that there were 127 patients receiving LA as initial ADT therapy, whereas the other 73 patients were in GA therapy. A total of 92 patients received LHRH analogue switching therapy (54 patients switched from LA to GA and 38 switched from GA to LA). The effect of LH and testosterone reduction prior to and after switching therapy was comparable between the two groups, and increased PSA level after 3 months of treatment was seen in both groups (median PSA: 15.7-67.7 ng/mL in the LA to GA group; 15.2-71.4 ng/mL in the GA to LA group). This study concluded that switching therapy for patients with PSA progression after ADT has no efficacy of further PSA response.

  6. Allosteric Modulation of Hormone Release from Thyroxine and Corticosteroid-binding Globulins*

    PubMed Central

    Qi, Xiaoqiang; Loiseau, François; Chan, Wee Lee; Yan, Yahui; Wei, Zhenquan; Milroy, Lech-Gustav; Myers, Rebecca M.; Ley, Steven V.; Read, Randy J.; Carrell, Robin W.; Zhou, Aiwu

    2011-01-01

    The release of hormones from thyroxine-binding globulin (TBG) and corticosteroid-binding globulin (CBG) is regulated by movement of the reactive center loop in and out of the β-sheet A of the molecule. To investigate how these changes are transmitted to the hormone-binding site, we developed a sensitive assay using a synthesized thyroxine fluorophore and solved the crystal structures of reactive loop cleaved TBG together with its complexes with thyroxine, the thyroxine fluorophores, furosemide, and mefenamic acid. Cleavage of the reactive loop results in its complete insertion into the β-sheet A and a substantial but incomplete decrease in binding affinity in both TBG and CBG. We show here that the direct interaction between residue Thr342 of the reactive loop and Tyr241 of the hormone binding site contributes to thyroxine binding and release following reactive loop insertion. However, a much larger effect occurs allosterically due to stretching of the connecting loop to the top of the D helix (hD), as confirmed in TBG with shortening of the loop by three residues, making it insensitive to the S-to-R transition. The transmission of the changes in the hD loop to the binding pocket is seen to involve coherent movements in the s2/3B loop linked to the hD loop by Lys243, which is, in turn, linked to the s4/5B loop, flanking the thyroxine-binding site, by Arg378. Overall, the coordinated movements of the reactive loop, hD, and the hormone binding site allow the allosteric regulation of hormone release, as with the modulation demonstrated here in response to changes in temperature. PMID:21325280

  7. Identification of major urinary metabolites of nafarelin acetate, a potent agonist of luteinizing hormone-releasing hormone, in the rhesus monkey

    SciTech Connect

    Chan, R.L.; Chaplin, M.D.

    1985-09-01

    Nafarelin acetate (less than Glu-His-Trp-Ser-Tyr-3-(2-naphthyl)-D-Ala-Leu-Arg-Pro-Gly-NH2) is a potent agonistic analogue of luteinizing hormone-releasing hormone. After a single iv administration of nafarelin acetate (with UC label at C-3 of 3-(2-naphthyl)-D-Ala) to female rhesus monkeys, about 80% of the radioactivity was eliminated in urine. Five major radioactive urinary metabolites were isolated and purified by reversed phase HPLC. Four of these metabolites, identified by amino acid analysis, were short peptides: the 5-10-hexapeptide amide, the 6-10-pentapeptide amide, the 5-7-tripeptide, and the 6-7-dipeptide. The fifth metabolite, which accounted for about 15% of the radioactivity administered, was shown by NMR and mass spectrometry to be 2-naphthylacetic acid. A possible pathway of its formation is by oxidative deamination of 3-(2-napthyl)-D-Ala to give the corresponding alpha-keto acid, followed by oxidative decarboxylation of the alpha-keto acid. These five metabolites together accounted for about 70% of the radioactivity recovered in the urine of rhesus monkeys, or more than half of the radioactivity in the administered dose. Nafarelin acetate was also present in small amounts. Several of these metabolites were also present in plasma of the rhesus monkey.

  8. Selected antimicrobial peptides inhibit in vitro growth of Campylobacter spp.

    USDA-ARS?s Scientific Manuscript database

    Novel alternatives to traditional antibiotics are urgently needed for food-animal production. A goal of our laboratory is to develop and evaluate antimicrobial peptides (AMP) to control and reduce foodborne pathogens in poultry. AMP have been found in most every class of living organism where they h...

  9. Biofilm mode of growth of Streptococcus intermedius favored by a competence-stimulating signaling peptide.

    PubMed

    Petersen, Fernanda C; Pecharki, Daniele; Scheie, Anne A

    2004-09-01

    Gram-positive and gram-negative bacteria use quorum sensing to coordinate population behavior. In several streptococci, quorum sensing mediated by competence-stimulating peptides (CSP) is associated with development of competence for transformation. We show here that a synthetic CSP favored the biofilm mode of growth of Streptococcus intermedius without affecting the rate of culture growth.

  10. Biochemical characterization of a new maize (Zea mays L.) peptide growth factor.

    PubMed

    Rodríguez-López, Cesar David; Rodríguez-Romero, Adela; Aguilar, Raúl; de Jiménez, Estela Sánchez

    2011-01-01

    Coordination of cell growth and cell division is very important for living organisms in order for these to develop harmonically. The present research is concerned with the purification and characterization of a new peptide hormone, namely ZmIGF (Zea mays insulin-like growth factor), which regulates growth and cell division in maize tissues. ZmIGF is a peptide of 5.7 kDa, as determined by mass spectroscopy. It was isolated either from maize embryonic axes of 48-h germinated seeds or from embryogenic callus and purified through several chromatographic procedures to obtain a single peak as shown by Reverse Phase High-Performance Liquid Chromatography (RP-HPLC). This peptide exhibits a well defined α-helix structure by circular dichroism analysis, similar to that reported for Insulin or for Insulin-like growth factor (IGF-1). Further, ZmIGF seems to perform, in maize, a similar function to that reported for insulin or peptides from the IGF family in animals. Indeed, maize tissues stimulated either by ZmIGF or insulin showed to induce selective synthesis of ribosomal proteins as well as of DNA. Taken together, the previously mentioned data strongly suggest that plants contain a peptide hormone of the IGF family, highly conserved through evolution that regulates growth and development.

  11. Message in a bottle: small signalling peptide outputs during growth and development.

    PubMed

    Czyzewicz, Nathan; Yue, Kun; Beeckman, Tom; De Smet, Ive

    2013-12-01

    Classical and recently found phytohormones play an important role in plant growth and development, but plants additionally control these processes through small signalling peptides. Over 1000 potential small signalling peptide sequences are present in the Arabidopsis genome. However, to date, a mere handful of small signalling peptides have been functionally characterized and few have been linked to a receptor. Here, we assess the potential small signalling peptide outputs, namely the molecular, biochemical, and morphological changes they trigger in Arabidopsis. However, we also include some notable studies in other plant species, in order to illustrate the varied effects that can be induced by small signalling peptides. In addition, we touch on some evolutionary aspects of small signalling peptides, as studying their signalling outputs in single-cell green algae and early land plants will assist in our understanding of more complex land plants. Our overview illustrates the growing interest in the small signalling peptide research area and its importance in deepening our understanding of plant growth and development.

  12. Reproductive characteristics of grass-fed, luteinizing hormone-releasing hormone-immunocastrated Bos indicus bulls.

    PubMed

    Hernandez, J A; Zanella, E L; Bogden, R; de Avila, D M; Gaskins, C T; Reeves, J J

    2005-12-01

    Two field trials were conducted in Brazil to evaluate LHRH immunocastration of Bos indicus bulls (d 0 = 2 yr of age). In Study I, 72 bulls were assigned randomly to one of three treatment groups: LHRH0-immunized, castrated, and intact. Immunized animals (n = 25) received a primary and two booster injections of ovalbumin-LHRH-7 and thioredoxin-LHRH-7 fusion proteins on d 0, 141, and 287. Twenty-three bulls were surgically castrated on d 141, and 24 served as intact controls. All animals were slaughtered on d 385, at approximately 3 yr of age. In Study II, 216 bulls were assigned randomly to the same three treatments as in Study I; however, because of a drought in the area, bulls were kept on pasture an additional year, and a fourth treatment was added, in which one-half the LHRH-immunized bulls received an additional booster on d 639 (fourth immunization). All animals in Study II were slaughtered on d 741 (4 yr of age). Luteinizing hormone-releasing hormone antibodies increased following each immunization for immunized bulls, but they were not detectable in castrate or intact animals in either study. Consequently, scrotal circumference was suppressed in immunized bulls compared with intact controls in both studies. By d 287, serum concentrations of testosterone in LHRH-immunized bulls were decreased compared with intact controls (P < 0.01). In both studies, testes and epididymal weights at slaughter were greater (P < 0.01) for intact (500 +/- 17 and 60 +/- 2 g, respectively) than for immunized bulls (173 +/- 22 and 26 +/- 2 g, respectively) and fourth immunization bulls (78 +/- 23 and 20 +/- 2 g, respectively; Study II). At the end of each study, BW was greater (P < 0.01) for intact bulls than for castrated and LHRH-immunized animals. In these two studies, the efficacy of the LHRH fusion proteins to induce an effect similar to that of surgical castration was considered 92 and 93%, respectively. These data support the concept that immunocastration of bulls at 2 yr of

  13. Inhibition of Growth and Gene Expression by PNA-peptide Conjugates in Streptococcus pyogenes

    PubMed Central

    Patenge, Nadja; Pappesch, Roberto; Krawack, Franziska; Walda, Claudia; Mraheil, Mobarak Abu; Jacob, Anette; Hain, Torsten; Kreikemeyer, Bernd

    2013-01-01

    While Streptococcus pyogenes is consistently susceptible toward penicillin, therapeutic failure of penicillin treatment has been reported repeatedly and a considerable number of patients exhibit allergic reactions to this substance. At the same time, streptococcal resistance to alternative antibiotics, e.g., macrolides, has increased. Taken together, these facts demand the development of novel therapeutic strategies. In this study, S. pyogenes growth was inhibited by application of peptide-conjugated antisense-peptide nucleic acids (PNAs) specific for the essential gyrase A gene (gyrA). Thereby, HIV-1 Tat peptide-coupled PNAs were more efficient inhibitors of streptococcal growth as compared with (KFF)3K-coupled PNAs. Peptide-anti-gyrA PNAs decreased the abundance of gyrA transcripts in S. pyogenes. Growth inhibition by antisense interference was enhanced by combination of peptide-coupled PNAs with protein-level inhibitors. Antimicrobial synergy could be detected with levofloxacin and novobiocin, targeting the gyrase enzyme, and with spectinomycin, impeding ribosomal function. The prospective application of carrier peptide-coupled antisense PNAs in S. pyogenes covers the use as an antimicrobial agent and the employment as a knock-down strategy for the investigation of virulence factor function. PMID:24193033

  14. Radioimmunoassay for 6-D-tryptophan analog of luteinizing hormone-releasing hormone: measurement of serum levels after administration of long-acting microcapsule formulations.

    PubMed Central

    Mason-Garcia, M; Vigh, S; Comaru-Schally, A M; Redding, T W; Somogyvari-Vigh, A; Horvath, J; Schally, A V

    1985-01-01

    A sensitive and specific radioimmunoassay for [6-D-tryptophan]luteinizing hormone-releasing hormone [( D-Trp6]LH-RH) was developed and used for following the rate of liberation of [D-Trp6]LH-RH from a long-acting delivery system based on a microcapsule formulation. Rabbit antibodies were generated against [D-Trp6]LH-RH conjugated to bovine serum albumin with glutaraldehyde. Crossreactivity with LH-RH was less than 1%; there was no significant crossreactivity with other peptides. The minimal detectable dose of [D-Trp6]LH-RH was 2 pg per tube. Intra- and interassay coefficients of variation were 8% and 10%, respectively. The radioimmunoassay was suitable for direct determination of [D-Trp6]LH-RH in serum, permitting the study of blood levels of the analog after single injections into normal men and after once-a-month administration of microcapsules to rats. In men, 90 min after subcutaneous injection of 250 micrograms of the peptide, serum [D-Trp6]LH-RH rose to 6-12 ng/ml. Luteinizing hormone was increased 90 min and 24 hr after the administration of the analog. Several batches of microcapsules were tested in rats and the rate of release of [D-Trp6]LH-RH was followed. The improved batch of microcapsules of [D-Trp6]LH-RH increased serum concentrations of the analog for 30 days or longer after intramuscular injection. This was accompanied by suppression of testosterone levels for more than 30 days. This radioimmunoassay should be of value for monitoring [D-Trp6]LH-RH during long-term therapy. PMID:3156381

  15. Cell-Penetrating Ability of Peptide Hormones: Key Role of Glycosaminoglycans Clustering.

    PubMed

    Neree, Armelle Tchoumi; Nguyen, Phuong Trang; Bourgault, Steve

    2015-11-16

    Over the last two decades, the potential usage of cell-penetrating peptides (CPPs) for the intracellular delivery of various molecules has prompted the identification of novel peptidic identities. However, cytotoxic effects and unpredicted immunological responses have often limited the use of various CPP sequences in the clinic. To overcome these issues, the usage of endogenous peptides appears as an appropriate alternative approach. The hormone pituitary adenylate-cyclase-activating polypeptide (PACAP38) has been recently identified as a novel and very efficient CPP. This 38-residue polycationic peptide is a member of the secretin/glucagon/growth hormone-releasing hormone (GHRH) superfamily, with which PACAP38 shares high structural and conformational homologies. In this study, we evaluated the cell-penetrating ability of cationic peptide hormones in the context of the expression of cell surface glycosaminoglycans (GAGs). Our results indicated that among all peptides evaluated, PACAP38 was unique for its potent efficiency of cellular uptake. Interestingly, the abilities of the peptides to reach the intracellular space did not correlate with their binding affinities to sulfated GAGs, but rather to their capacity to clustered heparin in vitro. This study demonstrates that the uptake efficiency of a given cationic CPP does not necessarily correlate with its affinity to sulfated GAGs and that its ability to cluster GAGs should be considered for the identification of novel peptidic sequences with potent cellular penetrating properties.

  16. Anti-tumor effects of peptide analogs targeting neuropeptide hormone receptors on mouse pheochromocytoma cells.

    PubMed

    Ziegler, C G; Ullrich, M; Schally, A V; Bergmann, R; Pietzsch, J; Gebauer, L; Gondek, K; Qin, N; Pacak, K; Ehrhart-Bornstein, M; Eisenhofer, G; Bornstein, S R

    2013-05-22

    Pheochromocytoma is a rare but potentially lethal chromaffin cell tumor with currently no effective treatment. Peptide hormone receptors are frequently overexpressed on endocrine tumor cells and can be specifically targeted by various anti-tumor peptide analogs. The present study carried out on mouse pheochromocytoma cells (MPCs) and a more aggressive mouse tumor tissue-derived (MTT) cell line revealed that these cells are characterized by pronounced expression of the somatostatin receptor 2 (sst2), growth hormone-releasing hormone (GHRH) receptor and the luteinizing hormone-releasing hormone (LHRH) receptor. We further demonstrated significant anti-tumor effects mediated by cytotoxic somatostatin analogs, AN-162 and AN-238, by LHRH antagonist, Cetrorelix, by the cytotoxic LHRH analog, AN-152, and by recently developed GHRH antagonist, MIA-602, on MPC and for AN-152 and MIA-602 on MTT cells. Studies of novel anti-tumor compounds on these mouse cell lines serve as an important basis for mouse models of metastatic pheochromocytoma, which we are currently establishing. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Anti-tumor effects of peptide analogs targeting neuropeptide hormone receptors on mouse pheochromocytoma cells

    PubMed Central

    Ziegler, CG; Ullrich, M; Schally, AV; Bergmann, R; Pietzsch, J; Gebauer, L; Gondek, K; Qin, N; Pacak, K; Ehrhart-Bornstein, M; Eisenhofer, G; Bornstein, SR

    2013-01-01

    Pheochromocytoma is a rare but potentially lethal chromaffin cell tumor with currently no effective treatment. Peptide hormone receptors are frequently overexpressed on endocrine tumor cells and can be specifically targeted by various anti-tumor peptide analogs. The present study carried out on mouse pheochromocytoma cells (MPC) and a more aggressive mouse tumor tissue-derived (MTT) cell line revealed that these cells are characterized by pronounced expression of the somatostatin receptor 2 (sst2), growth hormone-releasing hormone (GHRH) receptor and the luteinizing hormone-releasing hormone (LHRH) receptor. We further demonstrated significant anti-tumor effects mediated by cytotoxic somatostatin analogs, AN-162 and AN-238, by LHRH antagonist, Cetrorelix, by the cytotoxic LHRH analog, AN-152, and by recently developed GHRH antagonist, MIA-602, on MPC and for AN-152 and MIA-602 on MTT cells. Studies of novel anti-tumor compounds on these mouse cell lines serve as an important basis for mouse models of metastatic pheochromocytoma, which we are currently establishing. PMID:23267837

  18. Role of Osteogenic Growth Peptide (OGP) and OGP(10-14) in Bone Regeneration: A Review.

    PubMed

    Pigossi, Suzane C; Medeiros, Marcell C; Saska, Sybele; Cirelli, Joni A; Scarel-Caminaga, Raquel M

    2016-11-22

    Bone regeneration is a process that involves several molecular mediators, such as growth factors, which directly affect the proliferation, migration and differentiation of bone-related cells. The osteogenic growth peptide (OGP) and its C-terminal pentapeptide OGP(10-14) have been shown to stimulate the proliferation, differentiation, alkaline phosphatase activity and matrix mineralization of osteoblastic lineage cells. However, the exact molecular mechanisms that promote osteoblastic proliferation and differentiation are not completely understood. This review presents the main chemical characteristics of OGP and/or OGP(10-14), and also discusses the potential molecular pathways induced by these growth factors to promote proliferation and differentiation of osteoblasts. Furthermore, since these peptides have been extensively investigated for bone tissue engineering, the clinical applications of these peptides for bone regeneration are discussed.

  19. Role of Osteogenic Growth Peptide (OGP) and OGP(10–14) in Bone Regeneration: A Review

    PubMed Central

    Pigossi, Suzane C.; Medeiros, Marcell C.; Saska, Sybele; Cirelli, Joni A.; Scarel-Caminaga, Raquel M.

    2016-01-01

    Bone regeneration is a process that involves several molecular mediators, such as growth factors, which directly affect the proliferation, migration and differentiation of bone-related cells. The osteogenic growth peptide (OGP) and its C-terminal pentapeptide OGP(10–14) have been shown to stimulate the proliferation, differentiation, alkaline phosphatase activity and matrix mineralization of osteoblastic lineage cells. However, the exact molecular mechanisms that promote osteoblastic proliferation and differentiation are not completely understood. This review presents the main chemical characteristics of OGP and/or OGP(10–14), and also discusses the potential molecular pathways induced by these growth factors to promote proliferation and differentiation of osteoblasts. Furthermore, since these peptides have been extensively investigated for bone tissue engineering, the clinical applications of these peptides for bone regeneration are discussed. PMID:27879684

  20. Lactobacillus gasseri requires peptides, not proteins or free amino acids, for growth in milk.

    PubMed

    Arakawa, K; Matsunaga, K; Takihiro, S; Moritoki, A; Ryuto, S; Kawai, Y; Masuda, T; Miyamoto, T

    2015-03-01

    Lactobacillus gasseri is a widespread commensal lactic acid bacterium inhabiting human mucosal niches and has many beneficial effects as a probiotic. However, L. gasseri is difficult to grow in milk, which hurts usability for the food industry. It had been previously reported that supplementation with yeast extract or proteose peptone, including peptides, enables L. gasseri to grow well in milk. In this study, our objective was to confirm peptide requirement of L. gasseri and evaluate efficacy of peptide release by enzymatic proteolysis on growth of L. gassei in milk. Three strains of L. gasseri did not grow well in modified DeMan, Rogosa, Sharpe broth without any nitrogen sources (MRS-N), but addition of a casein-derived peptide mixture, tryptone, promoted growth. In contrast, little effect was observed after adding casein or a casein-derived amino acid mixture, casamino acids. These results indicate that L. gasseri requires peptides, not proteins or free amino acids, among milk-derived nitrogen sources for growth. Lactobacillus gasseri JCM 1131T hardly had growth capacity in 6 kinds of milk-based media: bovine milk, human milk, skim milk, cheese whey, modified MRS-N (MRSL-N) supplemented with acid whey, and MRSL-N supplemented with casein. Moreover, treatment with digestive proteases, particularly pepsin, to release peptides made it grow well in each milk-based medium. The pepsin treatment was the most effective for growth of strain JCM 1131T in skim milk among the tested food-grade proteases such as trypsin, α-chymotrypsin, calf rennet, ficin, bromelain, and papain. As well as strain JCM 1131T, pepsinolysis of milk improved growth of other L. gasseri strains and some strains of enteric lactobacilli such as Lactobacillus crispatus, Lactobacillus gallinarum, Lactobacillus johnsonii, and Lactobacillus reuteri. These results suggest that some relatives of L. gasseri also use peptides as desirable nitrogen sources, and that milk may be a good supplier of nutritious

  1. A mitogenic peptide amide encoded within the E peptide domain of the insulin-like growth factor IB prohormone.

    PubMed Central

    Siegfried, J M; Kasprzyk, P G; Treston, A M; Mulshine, J L; Quinn, K A; Cuttitta, F

    1992-01-01

    We have identified an amino acid sequence within the E peptide of the insulin-like growth factor IB (IGF-IB) precursor that is biologically active and designated this peptide insulin-like growth factor IB-(103-124) E1 amide (IBE1). Its existence was predicted by a flanking Gly-Lys-Lys-Lys, a signal sequence for sequential proteolytic cleavage and peptidyl C-terminal amidation. A synthetic analog of the predicted IBE1 peptide, designated Y-23-R-NH2, was generated with tyrosine added at position 0. This peptide at 2-20 nM had growth-promoting effects on both normal and malignant human bronchial epithelial cells. Y-23-R-NH2 bound to specific high-affinity receptors (Kd = 2.8 +/- 1.4 x 10(-11) M) present at 1-2 x 10(4) binding sites per cell. Ligand binding was not inhibited by recombinant insulin or recombinant IGF-I. Furthermore, a monoclonal antibody antagonist to the IGF-I receptor (alpha IR3) did not suppress the proliferative response induced by Y-23-R-NH2. In addition, C-terminal amidation was shown to be important in receptor recognition since the free-acid analog of IBE1 (Y-23-R-OH) did not effectively compete for binding and was not a potent agonist of proliferation. Immunoblot analysis of human lung tumor cell line extracts using an antibody raised against Y-23-R-NH2 detected a low molecular mass band of approximately 5 kDa, implying that a protein product is produced that has immunological similarity to IBE1. Extracts of human, mammalian, and avian livers analyzed on an immunoblot with the anti-Y-23-R-NH2 antibody contained proteins of approximately 21 kDa that were specifically recognized by the antiserum and presumably represent an IGF-I precursor molecule. This implies that in species where an IGF-I mRNA with homology to the human IGF-IB E domain has not yet been described, an alternate mRNA must be produced that contains a sequence similar to that of the midportion of the human IGF-IB E domain. Our findings demonstrate that IBE1 is a growth factor that

  2. Electrospun PELCL membranes loaded with QK peptide for enhancement of vascular endothelial cell growth.

    PubMed

    Yang, Yang; Yang, Qingmao; Zhou, Fang; Zhao, Yunhui; Jia, Xiaoling; Yuan, Xiaoyan; Fan, Yubo

    2016-06-01

    One of the major challenges in tissue engineering of small-diameter vascular grafts is to inhibit intimal hyperplasia and keep long-term patency after implantation. Rapid endothelialization of the grafts could be an effective approach. In this study, QK, a peptide mimicking vascular endothelial growth factor, was selected as the bioactive substrate and loaded in electrospun membranes for enhancement of vascular endothelial cell growth. In detail, QK peptide was firstly introduced with poly(ethylene glycol) diacrylate into a thiolated chitosan solution that could transfer into hydrogel. Then, suspensions or emulsions of poly(ethylene glycol)-b-poly(L-lactide-co-ε-caprolactone) (PELCL) containing QK peptide (with or without chitosan hydrogel) were electrospun into fibrous membranes. For comparison, the electrospun PELCL membrane without QK was also fabricated. Results of release behaviors showed that the electrospun membranes, especially that contained chitosan hydrogel prepared by suspension electrospinning, could successfully encapsulate QK peptide and maintain its secondary structure after released. In vitro cell culture studies exhibited that the release of QK peptide could accelerate the proliferation of vascular endothelial cells in the 9 days. It was suggested that the electrospun PELCL membranes loaded with QK peptide might have potential applications in vascular tissue engineering.

  3. Preferential megalin-mediated transcytosis of low-hormonogenic thyroglobulin: A control mechanism for thyroid hormone release

    PubMed Central

    Lisi, Simonetta; Pinchera, Aldo; McCluskey, Robert T.; Willnow, Thomas E.; Refetoff, Samuel; Marcocci, Claudio; Vitti, Paolo; Menconi, Francesca; Grasso, Lucia; Luchetti, Fabiana; Collins, A. Bernard; Marinò, Michele

    2003-01-01

    Hormone secretion by thyrocytes occurs by fluid phase uptake and lysosomal degradation of the prohormone thyroglobulin (Tg). However, some Tg internalized by megalin bypasses lysosomes and is transcytosed across cells and released into the bloodstream. Because the hormone content of Tg is variable, we investigated whether this affects transcytosis. We found that rat Tg with a low hormone content [low-hormonogenic rat Tg (low-horm-rTg)] is transcytosed by megalin across thyroid FRTL-5 cells to a greater extent than rat Tg with a high hormone content [hormonogenic rat Tg (horm-rTg)]. In immunoprecipitation experiments, the Tg sequence Arg-2489-Lys-2503 (required for binding to megalin and heparan sulfate proteoglycans) was found to be more exposed in low-horm-rTg, which accounted for its preferential transcytosis. Thus, removal of surface heparan sulfate proteoglycans from FRTL-5 cells or blocking of 2489–2503 reduced transcytosis of low-horm-rTg to a greater extent than that of horm-rTg. Preferential transcytosis of low-horm-rTg affected hormone release. Thus, the increase in hormone release from horm-rTg in FRTL-5 cells determined by megalin blocking (due to reduced transcytosis and enhanced Tg degradation) was rescued by low-horm-rTg, suggesting that megalin is required for effective hormone release. This finding was confirmed in a small number of megalin-deficient mice, which had serological features resembling mild hypothyroidism. Reduced hormone formation within Tg in vivo, due to treatment of rats with aminotriazole or of patients with Graves' disease with methimazole, resulted in increased Tg transcytosis via megalin, in confirmation of results with FRTL-5 cells. Our study points to a major role of megalin in thyroid homeostasis with possible implications in thyroid diseases. PMID:14657389

  4. A novel leptin antagonist peptide inhibits breast cancer growth in vitro and in vivo

    PubMed Central

    Catalano, Stefania; Leggio, Antonella; Barone, Ines; De Marco, Rosaria; Gelsomino, Luca; Campana, Antonella; Malivindi, Rocco; Panza, Salvatore; Giordano, Cinzia; Liguori, Alessia; Bonofiglio, Daniela; Liguori, Angelo; Andò, Sebastiano

    2015-01-01

    The role of the obesity cytokine leptin in breast cancer progression has raised interest in interfering with leptin's actions as a valuable therapeutic strategy. Leptin interacts with its receptor through three different binding sites: I–III. Site I is crucial for the formation of an active leptin–leptin receptor complex and in its subsequent activation. Amino acids 39-42 (Leu-Asp-Phe-Ile- LDFI) were shown to contribute to leptin binding site I and their mutations in alanine resulted in muteins acting as typical antagonists. We synthesized a small peptide based on the wild-type sequence of leptin binding site I (LDFI) and evaluated its efficacy in antagonizing leptin actions in breast cancer using in vitro and in vivo experimental models. The peptide LDFI abolished the leptin-induced anchorage-dependent and -independent growth as well as the migration of ERα-positive (MCF-7) and -negative (SKBR3) breast cancer cells. These results were well correlated with a reduction in the phosphorylation levels of leptin downstream effectors, as JAK2/STAT3/AKT/MAPK. Importantly, the peptide LDFI reversed the leptin-mediated up-regulation of its gene expression, as an additional mechanism able to enhance the peptide antagonistic activity. The described effects were specific for leptin signalling, since the developed peptide was not able to antagonize the other growth factors' actions on signalling activation, proliferation and migration. Finally, we showed that the LDFI pegylated peptide markedly reduced breast tumour growth in xenograft models. The unmodified peptide LDFI acting as a full leptin antagonist could become an attractive option for breast cancer treatment, especially in obese women. PMID:25721149

  5. Collagen IV and CXC chemokine derived anti-angiogenic peptides suppress glioma xenograft growth

    PubMed Central

    Rosca, Elena V.; Lal, Bachchu; Koskimaki, Jacob E.; Popel, Aleksander S.; Laterra, John

    2012-01-01

    Peptides are receiving increased attention as therapeutic agents, due to their high binding specificity and versatility to be modified as targeting or carrier molecules. Particularly, peptides with anti-angiogenic activity are of high interest due to their applicability to a wide range of cancers. In this study we investigate the biological activity of two novel antiangiogenic peptides in pre-clinical glioma models. One peptide SP2000 is derived from collagen IV and the other peptide SP3019 belongs to the CXC family. We previously characterized the capacity of SP2000 and SP3019 to inhibit multiple biological endpoints linked to angiogenesis in human endothelial cells in several assays. Here we report additional studies using endothelial cells and focus on the activity of these peptides against human glioma cell growth, migration and adhesion in vitro and growth as tumor xenografts in vivo. We found that SP2000 completely inhibits migration of the glioma cells at 50 μM and SP3019 produced 50% inhibition at 100 μM. Their relative anti-adhesion activities were similar with SP2000 and SP3019 generating 50% adhesion inhibition at 4.9 ± 0.82 μM and 21.3 ± 5.92 μM respectively. In vivo glioma growth inhibition was 63 % for SP2000 and 76% for SP3019 after 2 weeks of administration at daily doses of 10mg/kg and 20 mg/kg, respectively. The direct activity of these peptides against glioma cells in conjunction with their anti-angiogenic activities warrants their further development as either stand-alone agents or in combination with standard cytotoxic or emerging targeted therapies in malignant brain tumors. PMID:22495619

  6. Designing Signal Peptides for Efficient Periplasmic Expression of Human Growth Hormone in Escherichia coli.

    PubMed

    Khameneh, Meisam Jeirani; Moshiri, Farzaneh; Falasafi, Soheil Keyhan; Zomorodipour, Alireza

    2017-08-31

    Secretion efficiency of a protein in a SEC-type secretion system is mainly determined by an N-terminal signal peptide and its combination with its cognate protein. Five signal peptides, including; two synthetic Sec-type and three Bacillus licheniformis alpha-amylase derived signal peptides were compared for periplasmic expression of the human growth hormone (hGH) in E. coli. Based on in silico predictions on the signal peptides' cleavage efficiencies and their corresponding mRNA secondary structures, a number of amino acid substitutions and silent mutations were considered in the modified signal sequences. The two synthetic signal peptides, specifically designed for the hGH secretion in E. coli, differ in their N-terminal positively charged residues and hydrophobic regions lengths. According to the mRNA secondary structure predictions, combinations of the protein and each of the five signal sequences could lead to different outcomes, especially when accessibility of the initiator ATG and ribosome binding sites were considered. In the experimental stage, the two synthetic signal peptides displayed complete processing and resulted in efficient secretion of the mature hGH in periplasmic regions, as it was demonstrated by protein analysis. The three alpha-amylase-derived signal peptides, however, were processed partially from their precursors. Therefore, to achieve efficient secretion of a protein in a heterologous system, designing of a specific signal peptide in which a combined approach of optimizations of the mRNA secondary structure and the signal peptide H-domain and cleavage site is recommended.

  7. Inhibitory Effects of Synthetic Peptides Containing Bovine Lactoferrin C-lobe Sequence on Bacterial Growth

    PubMed Central

    Kim, Woan-Sub; Ohashi, Midori; Shimazaki, Kei-ichi

    2016-01-01

    Lactoferrin is a glycoprotein with various biological effects, with antibacterial activity being one of the first effects reported. This glycoprotein suppresses bacterial growth through bacteriostatic or bactericidal action. It also stimulates the growth of certain kinds of bacteria such as lactic acid bacteria and bifidobacteria. In this study, Asn-Leu-Asn-Arg was selected and chemically synthesized based on the partial sequences of bovine lactoferrin tryptic fragments. Synthetic Asn-Leu-Asn-Arg suppressed the growth of Pseudomonas fluorescens, P. syringae and Escherichia coli. P. fluorescens is a major psychrotrophic bacteria found in raw and pasteurized milk, which decreases milk quality. P. syringae is a harmful infectious bacterium that damages plants. However, synthetic Asn-Leu-Asn-Arg did not inhibit the growth of Lactobacillus acidophilus. It is expected that this synthetic peptide would be the first peptide sequence from the bovine lactoferrin C-lobe that shows antibacterial activity. PMID:27621684

  8. The inhibition of calcium carbonate crystal growth by the cysteine-rich Mdm2 peptide.

    PubMed

    Dalas, E; Chalias, A; Gatos, D; Barlos, K

    2006-08-15

    The crystal growth of calcite, the most stable calcium carbonate polymorph, in the presence of the cysteine-rich Mdm2 peptide (containing 48 amino acids in the ring finger configuration), has been investigated by the constant composition technique. Crystallization took place exclusively on well-characterized calcite crystals in solutions supersaturated only with respect to this calcium carbonate salt. The kinetic results indicated a surface diffusion spiral growth mechanism. The presence of the Mdm2 peptide inhibited the crystal growth of calcite by 22-58% in the concentration range tested, through adsorption onto the active growth sites of the calcite crystal surface. The kinetic results favored a Langmuir-type adsorption model, and the value of the calculated affinity constant was k(aff)=147x10(4) dm(3)mol(-1), a(ads)=0.29.

  9. Discrimination of recombinant and pituitary-derived bovine and porcine growth hormones by peptide mass mapping.

    PubMed

    Pinel, Gaud; André, François; Le Bizec, Bruno

    2004-02-11

    Somatotropins, which are used in cattle for growth and lactating performances, are difficult to reliably detect because no direct method exists. Reversed-phase high-performance liquid chromatography (RP-HLC) coupled to electrospray ionization quadrupole mass spectrometry (ESI/MS) has been developed to separate and characterize the N-terminal peptides resulting from tryptic cleavage of natural and recombinant growth hormones from different species (bovine, porcine, and human) and suppliers. Conditions for tryptic digestion were optimized. This technique was found to be optimal to cleave efficiently the N-terminal peptide of the proteins without releasing too much noise from the matrix. Characterization of the peptides through ESI(+)-MS allowed natural and recombinant growth hormones from bovine and porcine species with N-terminal amino acid sequences differing from one amino acid residue to be discriminated. However, the studied human growth hormones had similar primary sequences that did not permit any discrimination between recombinant and natural forms, thus confirming the known identity of these hormones. Protein digestions with pepsin and chymotrypsin were also compared but were not conclusive due to the too small N-terminal peptides released after proteolysis.

  10. Supramolecular polymeric peptide amphiphile vesicles for the encapsulation of basic fibroblast growth factor.

    PubMed

    Loh, Xian Jun; del Barrio, Jesús; Lee, Tung-Chun; Scherman, Oren A

    2014-03-21

    The synthesis of a supramolecular double hydrophilic peptide-conjugated polymer held together by cucurbit[8]uril (CB[8]) ternary complexation and its subsequent temperature triggered self-assembly into vesicles are described. Basic fibroblast growth factor can be easily loaded into the vesicles under benign conditions and their bioactivities can be preserved without the need for excipients such as heparin.

  11. Glucagon-like peptide 2 may mediate growth and development of the bovine gastrointestinal tract

    USDA-ARS?s Scientific Manuscript database

    Glucagon-like peptide 2 (GLP-2), secreted by enteroendocrine cells, promotes growth, reduces apoptosis, and enhances blood flow, nutrient absorption, and barrier function in intestinal epithelium of monogastric species. Regulatory functions of GLP-2 in the ruminant gastrointestinal tract (GIT) are u...

  12. Vascular Endothelial Growth Factor Peptide Ligands Explored by Competition Assay and Isothermal Titration Calorimetry.

    PubMed

    Reille-Seroussi, Marie; Gaucher, Jean-François; Desole, Claudia; Gagey-Eilstein, Nathalie; Brachet, Franck; Broutin, Isabelle; Vidal, Michel; Broussy, Sylvain

    2015-08-25

    The v114* cyclic peptide has been identified as a tight vascular endothelial growth factor (VEGF) ligand. Here we report on the use of isothermal titration calorimetry (ITC), 96-well plate competition assay, and circular dichroism (CD) to explore the binding determinants of a new set of related peptides. Anti-VEGF antibodies are currently used in the clinic for regulating angiogenesis in cancer and age-related macular degeneration treatment. In this context, our aim is to develop smaller molecular entities with high affinity for the growth factor by a structure activity relationship approach. The cyclic disulfide peptide v114* was modified in several ways, including truncation, substitution, and variation of the size and nature of the cycle. The results indicated that truncation or substitution of the four N-terminal amino acids did not cause severe loss in affinity, allowing potential peptide labeling. Increase of the cycle size or substitution of the disulfide bridge with a thioether linkage drastically decreased the affinity, due to an enthalpy penalty. The leucine C-terminal residue positively contributed to affinity. Cysteine N-terminal acetylation induced favorable ΔΔG° and ΔΔH° of binding, which correlated with free peptide CD spectra changes. We also propose a biochemical model to extrapolate Ki from IC50 values measured in the displacement assay. These calculated Ki correlate well with the Kd values determined by extensive direct and reverse ITC measurements.

  13. Expression of neuropeptide hormone receptors in human adrenal tumors and cell lines: antiproliferative effects of peptide analogues.

    PubMed

    Ziegler, C G; Brown, J W; Schally, A V; Erler, A; Gebauer, L; Treszl, A; Young, L; Fishman, L M; Engel, J B; Willenberg, H S; Petersenn, S; Eisenhofer, G; Ehrhart-Bornstein, M; Bornstein, S R

    2009-09-15

    Peptide analogues targeting various neuropeptide receptors have been used effectively in cancer therapy. A hallmark of adrenocortical tumor formation is the aberrant expression of peptide receptors relating to uncontrolled cell proliferation and hormone overproduction. Our microarray results have also demonstrated a differential expression of neuropeptide hormone receptors in tumor subtypes of human pheochromocytoma. In light of these findings, we performed a comprehensive analysis of relevant receptors in both human adrenomedullary and adrenocortical tumors and tested the antiproliferative effects of peptide analogues targeting these receptors. Specifically, we examined the receptor expression of somatostatin-type-2 receptor, growth hormone-releasing hormone (GHRH) receptor or GHRH receptor splice variant-1 (SV-1) and luteinizing hormone-releasing hormone (LHRH) receptor at the mRNA and protein levels in normal human adrenal tissues, adrenocortical and adrenomedullary tumors, and cell lines. Cytotoxic derivatives of somatostatin AN-238 and, to a lesser extent, AN-162, reduced cell numbers of uninduced and NGF-induced adrenomedullary pheochromocytoma cells and adrenocortical cancer cells. Both the splice variant of GHRH receptor SV-1 and the LHRH receptor were also expressed in adrenocortical cancer cell lines but not in the pheochromocytoma cell line. The GHRH receptor antagonist MZ-4-71 and LHRH antagonist Cetrorelix both significantly reduced cell growth in the adrenocortical cancer cell line. In conclusion, the expression of receptors for somatostatin, GHRH, and LHRH in the normal human adrenal and in adrenal tumors, combined with the growth-inhibitory effects of the antitumor peptide analogues, may make possible improved treatment approaches to adrenal tumors.

  14. VGF Changes during the Estrous Cycle: A Novel Endocrine Role for TLQP Peptides?

    PubMed Central

    Noli, Barbara; Brancia, Carla; D’Amato, Filomena; Ferri, Gian-Luca; Cocco, Cristina

    2014-01-01

    Although the VGF derived peptide TLQP-21 stimulates gonadotropin-releasing hormone (GnRH) and gonadotropin secretion, available data on VGF peptides and reproduction are limited. We used antibodies specific for the two ends of the VGF precursor, and for two VGF derived peptides namely TLQP and PGH, to be used in immunohistochemistry and enzyme-linked immunosorbent assay complemented with gel chromatography. In cycling female rats, VGF C-/N-terminus and PGH peptide antibodies selectively labelled neurones containing either GnRH, or kisspeptin (VGF N-terminus only), pituitary gonadotrophs and lactotrophs, or oocytes (PGH peptides only). Conversely, TLQP peptides were restricted to somatostatin neurones, gonadotrophs, and ovarian granulosa, interstitial and theca cells. TLQP levels were highest, especially in plasma and ovary, with several molecular forms shown in chromatography including one compatible with TLQP-21. Among the cycle phases, TLQP levels were higher during metestrus-diestrus in median eminence and pituitary, while increased in the ovary and decreased in plasma during proestrus. VGF N- and C-terminus peptides also showed modulations over the estrous cycle, in median eminence, pituitary and plasma, while PGH peptides did not. In ovariectomised rats, plasmatic TLQP peptide levels showed distinct reduction suggestive of a major origin from the ovary, while the estrogen-progesterone treatment modulated VGF C-terminus and TLQP peptides in the hypothalamus-pituitary complex. In in vitro hypothalamus, TLQP-21 stimulated release of growth hormone releasing hormone but not of somatostatin. In conclusion, various VGF peptides may regulate the hypothalamus-pituitary complex via specific neuroendocrine mechanisms while TLQP peptides may act at further, multiple levels via endocrine mechanisms involving the ovary. PMID:25280008

  15. Growth-Blocking Peptides As Nutrition-Sensitive Signals for Insulin Secretion and Body Size Regulation

    PubMed Central

    Koyama, Takashi; Mirth, Christen K.

    2016-01-01

    In Drosophila, the fat body, functionally equivalent to the mammalian liver and adipocytes, plays a central role in regulating systemic growth in response to nutrition. The fat body senses intracellular amino acids through Target of Rapamycin (TOR) signaling, and produces an unidentified humoral factor(s) to regulate insulin-like peptide (ILP) synthesis and/or secretion in the insulin-producing cells. Here, we find that two peptides, Growth-Blocking Peptide (GBP1) and CG11395 (GBP2), are produced in the fat body in response to amino acids and TOR signaling. Reducing the expression of GBP1 and GBP2 (GBPs) specifically in the fat body results in smaller body size due to reduced growth rate. In addition, we found that GBPs stimulate ILP secretion from the insulin-producing cells, either directly or indirectly, thereby increasing insulin and insulin-like growth factor signaling activity throughout the body. Our findings fill an important gap in our understanding of how the fat body transmits nutritional information to the insulin producing cells to control body size. PMID:26928023

  16. Enhancing peptide ligand binding to vascular endothelial growth factor by covalent bond formation.

    PubMed

    Marquez, Bernadette V; Beck, Heather E; Aweda, Tolulope A; Phinney, Brett; Holsclaw, Cynthia; Jewell, William; Tran, Diana; Day, Jeffrey J; Peiris, Malalage N; Nwosu, Charles; Lebrilla, Carlito; Meares, Claude F

    2012-05-16

    Formation of a stable covalent bond between a synthetic probe molecule and a specific site on a target protein has many potential applications in biomedical science. For example, the properties of probes used as receptor-imaging ligands may be improved by increasing their residence time on the targeted receptor. Among the more interesting cases are peptide ligands, the strongest of which typically bind to receptors with micromolar dissociation constants, and which may depend on processes other than simple binding to provide images. The side chains of cysteine, histidine, or lysine are attractive for chemical attachment to improve binding to a receptor protein, and a system based on acryloyl probes attaching to engineered cysteine provides excellent positron emission tomographic images in animal models (Wei et al. (2008) J. Nucl. Med. 49, 1828-1835). In nature, lysine is a more common but less reactive residue than cysteine, making it an interesting challenge to modify. To seek practically useful cross-linking yields with naturally occurring lysine side chains, we have explored not only acryloyl but also other reactive linkers with different chemical properties. We employed a peptide-VEGF model system to discover that a 19mer peptide ligand, which carried a lysine-tagged dinitrofluorobenzene group, became attached stably and with good yield to a unique lysine residue on human vascular endothelial growth factor (VEGF), even in the presence of 70% fetal bovine serum. The same peptide carrying acryloyl and related Michael acceptors gave low yields of attachment to VEGF, as did the chloroacetyl peptide.

  17. Thiol-disulfide exchange in peptides derived from human growth hormone.

    PubMed

    Chandrasekhar, Saradha; Epling, Daniel E; Sophocleous, Andreas M; Topp, Elizabeth M

    2014-04-01

    Disulfide bonds stabilize proteins by cross-linking distant regions into a compact three-dimensional structure. They can also participate in hydrolytic and oxidative pathways to form nonnative disulfide bonds and other reactive species. Such covalent modifications can contribute to protein aggregation. Here, we present experimental data for the mechanism of thiol-disulfide exchange in tryptic peptides derived from human growth hormone in aqueous solution. Reaction kinetics was monitored to investigate the effect of pH (6.0-10.0), temperature (4-50°C), oxidation suppressants [ethylenediaminetetraacetic acid (EDTA) and N2 sparging], and peptide secondary structure (amide cyclized vs. open form). The concentrations of free thiol containing peptides, scrambled disulfides, and native disulfide-linked peptides generated via thiol-disulfide exchange and oxidation reactions were determined using reverse-phase HPLC and liquid chromatography-mass spectrometry. Concentration versus time data were fitted to a mathematical model using nonlinear least squares regression analysis. At all pH values, the model was able to fit the data with R(2) ≥ 0.95. Excluding oxidation suppressants (EDTA and N2 sparging) resulted in an increase in the formation of scrambled disulfides via oxidative pathways but did not influence the intrinsic rate of thiol-disulfide exchange. In addition, peptide secondary structure was found to influence the rate of thiol-disulfide exchange.

  18. Nanostructured materials based on mesoporous silica and mesoporous silica/apatite as osteogenic growth peptide carriers.

    PubMed

    Mendes, L S; Saska, S; Martines, M A U; Marchetto, R

    2013-10-01

    The aim of this work was the preparation of inorganic mesoporous materials from silica, calcium phosphate and a nonionic surfactant and to evaluate the incorporation and release of different concentrations of osteogenic growth peptide (OGP) for application in bone regeneration. The adsorption and release of the labeled peptide with 5,6-carboxyfluorescein (OGP-CF) from the mesoporous matrix was monitored by fluorescence spectroscopy. The specific surface area was 880 and 484 m(2) g(-1) for pure silica (SiO) and silica/apatite (SiCaP), respectively; the area influenced the percentage of incorporation of the peptide. The release of OGP-CF from the materials in simulated body fluid (SBF) was dependent on the composition of the particles, the amount of incorporated peptide and the degradation of the material. The release of 50% of the peptide content occurred at around 4 and 30 h for SiCaP and SiO, respectively. In conclusion, the materials based on SiO and SiCaP showed in vitro bioactivity and degradation; thus, these materials should be considered as alternative biomaterials for bone regeneration.

  19. Affinity Peptides Protect Transforming Growth Factor Beta During Encapsulation in Poly(ethylene glycol) Hydrogels

    PubMed Central

    2011-01-01

    Transforming growth factor beta (TGFβ1) influences a host of cellular fates, including proliferation, migration, and differentiation. Due to its short half-life and cross reactivity with a variety of cells, clinical application of TGFβ1 may benefit from a localized delivery strategy. Photoencapsulation of proteins in polymeric matrices offers such an opportunity; however, the reactions forming polymer networks often result in lowered protein bioactivity. Here, PEG-based gels formed from the chain polymerization of acrylated monomers were studied as a model system for TGFβ1 delivery. Concentrations of acrylate group ranging from 0 to 50 mM and photopolymerization conditions were systematically altered to study their effects on TGFβ1 bioactivity. In addition, two peptide sequences, WSHW (KD = 8.20 nM) and KRIWFIPRSSWY (KD = 10.41 nM), that exhibit binding affinity for TGFβ1 were introduced into the monomer solution prior to encapsulation to determine if affinity binders would increase the activity and release of the encapsulated growth factor. The addition of affinity peptides enhanced the bioactivity of TGFβ1 in vitro from 1.3- to 2.9-fold, compared to hydrogels with no peptide. Further, increasing the concentration of affinity peptides by a factor of 100−10000 relative to the TGFβ1 concentration increased fractional recovery of the protein from PEG hydrogels. PMID:21375234

  20. Affinity peptides protect transforming growth factor beta during encapsulation in poly(ethylene glycol) hydrogels.

    PubMed

    McCall, Joshua D; Lin, Chien-Chi; Anseth, Kristi S

    2011-04-11

    Transforming growth factor beta (TGFβ(1)) influences a host of cellular fates, including proliferation, migration, and differentiation. Due to its short half-life and cross reactivity with a variety of cells, clinical application of TGFβ(1) may benefit from a localized delivery strategy. Photoencapsulation of proteins in polymeric matrices offers such an opportunity; however, the reactions forming polymer networks often result in lowered protein bioactivity. Here, PEG-based gels formed from the chain polymerization of acrylated monomers were studied as a model system for TGFβ(1) delivery. Concentrations of acrylate group ranging from 0 to 50 mM and photopolymerization conditions were systematically altered to study their effects on TGFβ(1) bioactivity. In addition, two peptide sequences, WSHW (K(D) = 8.20 nM) and KRIWFIPRSSWY (K(D) = 10.41 nM), that exhibit binding affinity for TGFβ(1) were introduced into the monomer solution prior to encapsulation to determine if affinity binders would increase the activity and release of the encapsulated growth factor. The addition of affinity peptides enhanced the bioactivity of TGFβ(1) in vitro from 1.3- to 2.9-fold, compared to hydrogels with no peptide. Further, increasing the concentration of affinity peptides by a factor of 100-10000 relative to the TGFβ(1) concentration increased fractional recovery of the protein from PEG hydrogels.

  1. Long-term suppression of ovarian function by a luteinizing-hormone releasing hormone agonist implant in patients with endometriosis.

    PubMed

    Fraser, H M; Sandow, J; Cowen, G M; Lumsden, M A; Haining, R; Smith, S K

    1990-01-01

    Ten endometriosis patients received luteinizing hormone releasing hormone (LH-RH) agonist (buserelin) implant injections (6.6 mg subcutaneously) at days 0, 42, 84 and 126. Serum LH and follicle-stimulating hormone (FSH) were lowered by day 14. Luteinizing hormone remained at basal concentrations while FSH returned to values in the low-normal range of the menstrual cycle by day 35. At the end of the luteal phase during which treatment commenced, estrone and pregnanediol declined and remained at postmenopausal or early follicular phase values until days 305 to 460. Time to first ovulation ranged from 321 to 481 days after starting treatment. After the initial menstruation, only three instances of bleeding occurred during treatment. Pelvic pain was relieved or markedly reduced by day 42 and remained absent throughout the period of ovarian suppression. These results indicate the potential of a long-acting LH-RH agonist implant to form the basis for the treatment of symptomatic endometriosis.

  2. Effect of PEGylation on stability of peptide in poly(lactide-co-glycolide) microspheres.

    PubMed

    Park, Eun Ji; Tak, Tae Hyuk; Na, Dong Hee; Lee, Kang Choon

    2010-07-01

    The purpose of this study was to evaluate the effect of PEGylation on the stabilization of peptide in poly(D,L-lactide-co-glycolide) (PLGA) microspheres for sustained release delivery. As model peptide, growth hormone-releasing peptide-6 (GHRP-6) was conjugated with succinimidyl propionate monomethoxy poly(ethylene glycol) (PEG) with an average molecular weight of 2000 Da. The mono-PEG-GHRP-6 was separated by ion-exchange chromatography, and its molecular mass was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The microspheres encapsulating native GHRP-6 or mono-PEG-GHRP-6 were prepared using the single oil-in-water emulsion solvent evaporation method. During incubation in a 0.1 M phosphate buffer (pH 7.4) for one month at 37 degrees C, native GHRP-6 microspheres were identified to form several acylated peptides by reversed-phase HPLC and MALDI-TOF MS, whereas the mono-PEG-GHRP-6 microspheres was not affected from peptide acylation by PLGA. This study demonstrates that PEGylation can stabilize peptide against the acylation reaction occurred in PLGA microspheres.

  3. Restrain of bone growth by estrogen-mimetic peptide-1 (EMP-1): a micro-computed tomographic study.

    PubMed

    Kasher, Roni; Bajayo, Alon; Gabet, Yankel; Nevo, Nava; Fridkin, Mati; Katchalski-Katzir, Ephraim; Kohen, Fortune; Bab, Itai

    2009-06-01

    Estrogen has a key role in the regulation of skeletal growth and maintenance of bone mass. Recently, we developed peptides having estrogen-like activity as potential estrogen-based new drugs. The aim of the present study was to evaluate the influence of long-term administration of the most efficacious of these peptides, the hexapeptide EMP-1 (VSWFFE), on bone mass and development. EMP-1 was injected daily to ovariectomized (OVX) and intact young, sexually mature female mice for 10 weeks. Whole femora, including the cartilaginous growth plates were analyzed by micro-computed tomography (microCT). We found that peptide EMP-1 restrains bone growth in OVX mice: it inhibited dramatically bone longitudinal growth (40%), and decreased femoral diaphyseal diameter. Peptide EMP-1 had no effect on bone growth in normal mice, and did not influence the OVX-induced bone loss. We then developed a new microCT methodology to evaluate uncalcified and calcified growth plate parameters. In the OVX mice, peptide EMP-1 reduced volume and thickness of the uncalcified growth plate, a possible cause for the inhibition of bone longitudinal growth. Peptide EMP-1 may be used as a lead compound for the development of drugs to treat acromegalic patients.

  4. Conformational Flexibility and pH Effects on Anisotropic Growth of Sheet-Like Assembly of Amphiphilic Peptides.

    PubMed

    Huang, Hongzhou; Ganguly, Debabani; Chen, Jianhan; Sun, Xiuzhi S

    2015-06-01

    Peptide-based biomaterials have many potential applications in tissue engineering, drug delivery, surface engineering, and other areas. In this study, we exploited a series of amphiphilic diblock model peptides (L5K10, L5GSIIK10, and L5P(D)PK10) to understand how the supramolecular assembly morphology may be modulated by the physical properties of the peptide monomer and experimental conditions. A combination of experimentation and simulation revealed that although all three peptides lack stable structures as monomers, their levels of conformational heterogeneity differ significantly. Importantly, such differences appear to be correlated with the peptides' ability to form sheet-like assemblies. In particular, substantial conformational heterogeneity appears to be required for anisotropic growth of sheet-like materials, likely by reducing the peptide assembly kinetics. To test this hypothesis, we increased the pH to neutralize the lysine residues and promote peptide aggregation, and the resulting faster assembly rate hindered the growth of the sheet morphology as predicted. In addition, we designed and investigated the assembly morphologies of a series of diblock peptides with various lengths of polyglycine inserts, L5GxK10, x = 1, 2, 3, 4. The results further supported the importance of peptide conformational flexibility and pH in modulation of the peptide supramolecular assembly morphology.

  5. Peptides of Matrix Gla Protein Inhibit Nucleation and Growth of Hydroxyapatite and Calcium Oxalate Monohydrate Crystals

    PubMed Central

    Goiko, Maria; Dierolf, Joshua; Gleberzon, Jared S.; Liao, Yinyin; Grohe, Bernd; Goldberg, Harvey A.; de Bruyn, John R.; Hunter, Graeme K.

    2013-01-01

    Matrix Gla protein (MGP) is a phosphorylated and γ-carboxylated protein that has been shown to prevent the deposition of hydroxyapatite crystals in the walls of blood vessels. MGP is also expressed in kidney and may inhibit the formation of kidney stones, which mainly consist of another crystalline phase, calcium oxalate monohydrate. To determine the mechanism by which MGP prevents soft-tissue calcification, we have synthesized peptides corresponding to the phosphorylated and γ-carboxylated sequences of human MGP in both post-translationally modified and non-modified forms. The effects of these peptides on hydroxyapatite formation and calcium oxalate crystallization were quantified using dynamic light scattering and scanning electron microscopy, respectively. Peptides YGlapS (MGP1-14: YγEpSHEpSMEpSYELNP), YEpS (YEpSHEpSMEpSYELNP), YGlaS (YγESHESMESYELNP) and SK-Gla (MGP43-56: SKPVHγELNRγEACDD) inhibited formation of hydroxyapatite in order of potency YGlapS > YEpS > YGlaS > SK-Gla. The effects of YGlapS, YEpS and YGlaS on hydroxyapatite formation were on both crystal nucleation and growth; the effect of SK-Gla was on nucleation. YGlapS and YEpS significantly inhibited the growth of calcium oxalate monohydrate crystals, while simultaneously promoting the formation of calcium oxalate dihydrate. The effects of these phosphopeptides on calcium oxalate monohydrate formation were on growth of crystals rather than nucleation. We have shown that the use of dynamic light scattering allows inhibitors of hydroxyapatite nucleation and growth to be distinguished. We have also demonstrated for the first time that MGP peptides inhibit the formation of calcium oxalate monohydrate. Based on the latter finding, we propose that MGP function not only to prevent blood-vessel calcification but also to inhibit stone formation in kidney. PMID:24265810

  6. Peptides of Matrix Gla protein inhibit nucleation and growth of hydroxyapatite and calcium oxalate monohydrate crystals.

    PubMed

    Goiko, Maria; Dierolf, Joshua; Gleberzon, Jared S; Liao, Yinyin; Grohe, Bernd; Goldberg, Harvey A; de Bruyn, John R; Hunter, Graeme K

    2013-01-01

    Matrix Gla protein (MGP) is a phosphorylated and γ-carboxylated protein that has been shown to prevent the deposition of hydroxyapatite crystals in the walls of blood vessels. MGP is also expressed in kidney and may inhibit the formation of kidney stones, which mainly consist of another crystalline phase, calcium oxalate monohydrate. To determine the mechanism by which MGP prevents soft-tissue calcification, we have synthesized peptides corresponding to the phosphorylated and γ-carboxylated sequences of human MGP in both post-translationally modified and non-modified forms. The effects of these peptides on hydroxyapatite formation and calcium oxalate crystallization were quantified using dynamic light scattering and scanning electron microscopy, respectively. Peptides YGlapS (MGP1-14: YγEpSHEpSMEpSYELNP), YEpS (YEpSHEpSMEpSYELNP), YGlaS (YγESHESMESYELNP) and SK-Gla (MGP43-56: SKPVHγELNRγEACDD) inhibited formation of hydroxyapatite in order of potency YGlapS > YEpS > YGlaS > SK-Gla. The effects of YGlapS, YEpS and YGlaS on hydroxyapatite formation were on both crystal nucleation and growth; the effect of SK-Gla was on nucleation. YGlapS and YEpS significantly inhibited the growth of calcium oxalate monohydrate crystals, while simultaneously promoting the formation of calcium oxalate dihydrate. The effects of these phosphopeptides on calcium oxalate monohydrate formation were on growth of crystals rather than nucleation. We have shown that the use of dynamic light scattering allows inhibitors of hydroxyapatite nucleation and growth to be distinguished. We have also demonstrated for the first time that MGP peptides inhibit the formation of calcium oxalate monohydrate. Based on the latter finding, we propose that MGP function not only to prevent blood-vessel calcification but also to inhibit stone formation in kidney.

  7. In vitro growth of growth of campylobacter spp. inhibited by selected antimicrobial peptides

    USDA-ARS?s Scientific Manuscript database

    Background: Novel alternatives to traditional antibiotics are urgently needed for food-animal production. A goal of our laboratory is to develop and evaluate antimicrobial peptides (AMP) to control and reduce foodborne pathogens in poultry. AMP have been found in most every class of living organism...

  8. Signature motif-guided identification of receptors for peptide hormones essential for root meristem growth.

    PubMed

    Song, Wen; Liu, Li; Wang, Jizong; Wu, Zhen; Zhang, Heqiao; Tang, Jiao; Lin, Guangzhong; Wang, Yichuan; Wen, Xing; Li, Wenyang; Han, Zhifu; Guo, Hongwei; Chai, Jijie

    2016-06-01

    Peptide-mediated cell-to-cell signaling has crucial roles in coordination and definition of cellular functions in plants. Peptide-receptor matching is important for understanding the mechanisms underlying peptide-mediated signaling. Here we report the structure-guided identification of root meristem growth factor (RGF) receptors important for plant development. An assay based on a signature ligand recognition motif (Arg-x-Arg) conserved in a subfamily of leucine-rich repeat receptor kinases (LRR-RKs) identified the functionally uncharacterized LRR-RK At4g26540 as a receptor of RGF1 (RGFR1). We further solved the crystal structure of RGF1 in complex with the LRR domain of RGFR1 at a resolution of 2.6 Å, which reveals that the Arg-x-Gly-Gly (RxGG) motif is responsible for specific recognition of the sulfate group of RGF1 by RGFR1. Based on the RxGG motif, we identified additional four RGFRs. Participation of the five RGFRs in RGF-induced signaling is supported by biochemical and genetic data. We also offer evidence showing that SERKs function as co-receptors for RGFs. Taken together, our study identifies RGF receptors and co-receptors that can link RGF signals with their downstream components and provides a proof of principle for structure-based matching of LRR-RKs with their peptide ligands.

  9. Calcium carbonate crystal growth beneath Langmuir monolayers of acidic β-hairpin peptides.

    PubMed

    Gong, Haofei; Yang, Yi; Pluntke, Manuela; Marti, Othmar; Majer, Zsuzsa; Sewald, Norbert; Volkmer, Dirk

    2014-11-28

    Four amphiphilic peptides with designed hairpin structure were synthesized and their monolayers were employed as model systems to study biologically inspired calcium carbonate crystallization. Langmuir monolayers of hairpin peptides were investigated by surface pressure area isotherms, surface potential isotherms, Brewster angle microscopy (BAM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. A β-hairpin conformation was found for all peptides at the air-water interface although their packing arrangements seem to be different. Crystallization of calcium carbonate under these peptide monolayers was investigated at different surface pressures and growth times both by in situ optical microscopy, BAM and ex situ investigations such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An amorphous calcium carbonate precursor was found at the initial crystallization stage. The crystallization process occurred in three stages. It starts from the nucleation of amorphous particles being a kinetically controlled process. Crystal nuclei subsequently aggregate to large particles and vaterite crystals start to form inside the amorphous layer, with the monolayer fluidity exerting an important role. The third process includes the re-crystallization of vaterite to calcite, which is thermodynamically controlled by monolayer structural factors including the monolayer flexibility and packing arrangement of the polar headgroups. Thus, the kinetic factors, monolayer fluidity and flexibility as well as structure factors govern the crystal morphology and polymorph distribution simultaneously and synergistically.

  10. FAIMS and Phosphoproteomics of Fibroblast Growth Factor Signaling: Enhanced Identification of Multiply Phosphorylated Peptides.

    PubMed

    Zhao, Hongyan; Cunningham, Debbie L; Creese, Andrew J; Heath, John K; Cooper, Helen J

    2015-12-04

    We have applied liquid chromatography high-field asymmetric waveform ion mobility spectrometry tandem mass spectrometry (LC-FAIMS-MS/MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) to the investigation of site-specific phosphorylation in fibroblast growth factor (FGF) signaling. We have combined a SILAC approach with chemical inhibition by SU5402 (an FGF receptor tyrosine kinase inhibitor) and dasatinib (a Src family kinase inhibitor). The results show that incorporation of FAIMS within the workflow results in (a) an increase in the relative proportion of phosphothreonine and phosphotyrosine sites identified, (b) an increase in phosphopeptide identifications from precursors with charge states ≥ +3 (with an associated increase in peptide length), and (c) an increase in the identification of multiply phosphorylated peptides. Approximately 20% of the phosphorylation sites identified via the FAIMS workflow had not been reported previously, and over 80% of those were from multiply phosphorylated peptides. Moreover, FAIMS provided access to a distinct set of phosphorylation sites regulated in response to SU5402 and dasatinib. The enhanced identification of multiply phosphorylated peptides was particularly striking in the case of sites regulated by SU5402. In addition to providing a compelling example of the complementarity of FAIMS in phosphoproteomics, the results provide a valuable resource of phosphorylation sites for further investigation of FGF signaling and trafficking.

  11. The effect of luteinizing hormone releasing hormone analog regime and stage of oocyte maturity for induced ovulation of channel catfish Ictalurus punctatus

    USDA-ARS?s Scientific Manuscript database

    The effective LHRHa (luteinizing hormone releasing hormone analog) dose based on the gonadal maturity of channel catfish, Ictalurus punctatus to optimize channel x blue hybrid catfish production was evaluated in 4 trials (twice in early part of the season and twice in the peak spawning season) in a ...

  12. Effect of the artificial sweetener, sucralose, on gastric emptying and incretin hormone release in healthy subjects

    PubMed Central

    Ma, Jing; Bellon, Max; Wishart, Judith M.; Young, Richard; Blackshaw, L. Ashley; Jones, Karen L.; Horowitz, Michael; Rayner, Christopher K.

    2009-01-01

    The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), play an important role in glucose homeostasis in both health and diabetes. In mice, sucralose, an artificial sweetener, stimulates GLP-1 release via sweet taste receptors on enteroendocrine cells. We studied blood glucose, plasma levels of insulin, GLP-1, and GIP, and gastric emptying (by a breath test) in 7 healthy humans after intragastric infusions of 1) 50 g sucrose in water to a total volume of 500 ml (∼290 mosmol/l), 2) 80 mg sucralose in 500 ml normal saline (∼300 mosmol/l, 0.4 mM sucralose), 3) 800 mg sucralose in 500 ml normal saline (∼300 mosmol/l, 4 mM sucralose), and 4) 500 ml normal saline (∼300 mosmol/l), all labeled with 150 mg 13C-acetate. Blood glucose increased only in response to sucrose (P < 0.05). GLP-1, GIP, and insulin also increased after sucrose (P = 0.0001) but not after either load of sucralose or saline. Gastric emptying of sucrose was slower than that of saline (t50: 87.4 ± 4.1 min vs. 74.7 ± 3.2 min, P < 0.005), whereas there were no differences in t50 between sucralose 0.4 mM (73.7 ± 3.1 min) or 4 mM (76.7 ± 3.1 min) and saline. We conclude that sucralose, delivered by intragastric infusion, does not stimulate insulin, GLP-1, or GIP release or slow gastric emptying in healthy humans. PMID:19221011

  13. Targeting luteinizing hormone-releasing hormone: A potential therapeutics to treat gynecological and other cancers.

    PubMed

    Ghanghoria, Raksha; Kesharwani, Prashant; Tekade, Rakesh K; Jain, Narendra K

    2016-11-10

    development of a more systematic approach to the targeted delivery of cytotoxic agents using peptides.

  14. Effect of the artificial sweetener, sucralose, on gastric emptying and incretin hormone release in healthy subjects.

    PubMed

    Ma, Jing; Bellon, Max; Wishart, Judith M; Young, Richard; Blackshaw, L Ashley; Jones, Karen L; Horowitz, Michael; Rayner, Christopher K

    2009-04-01

    The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), play an important role in glucose homeostasis in both health and diabetes. In mice, sucralose, an artificial sweetener, stimulates GLP-1 release via sweet taste receptors on enteroendocrine cells. We studied blood glucose, plasma levels of insulin, GLP-1, and GIP, and gastric emptying (by a breath test) in 7 healthy humans after intragastric infusions of 1) 50 g sucrose in water to a total volume of 500 ml (approximately 290 mosmol/l), 2) 80 mg sucralose in 500 ml normal saline (approximately 300 mosmol/l, 0.4 mM sucralose), 3) 800 mg sucralose in 500 ml normal saline (approximately 300 mosmol/l, 4 mM sucralose), and 4) 500 ml normal saline (approximately 300 mosmol/l), all labeled with 150 mg 13C-acetate. Blood glucose increased only in response to sucrose (P<0.05). GLP-1, GIP, and insulin also increased after sucrose (P=0.0001) but not after either load of sucralose or saline. Gastric emptying of sucrose was slower than that of saline (t50: 87.4+/-4.1 min vs. 74.7+/-3.2 min, P<0.005), whereas there were no differences in t50 between sucralose 0.4 mM (73.7+/-3.1 min) or 4 mM (76.7+/-3.1 min) and saline. We conclude that sucralose, delivered by intragastric infusion, does not stimulate insulin, GLP-1, or GIP release or slow gastric emptying in healthy humans.

  15. Inhibition of new vessel growth in mouse model of laser-induced choroidal neovascularization by adiponectin peptide II

    PubMed Central

    Lyzogubov, Valeriy V.; Tytarenko, Ruslana G.; Thotakura, Sushma; Viswanathan, Tito; Bora, Nalini S.; Bora, Puran S.

    2012-01-01

    We have investigated the effect of adiponectin (APN) peptide II on new vessel growth in mouse model of choroidal neovascularization (CNV) or wet type age-related macular degeneration (AMD). Mice were injected intraperitoneally with APN peptide II, control peptide, or PBS on day 1–7 or day 5–14. APN, AdipoR1, PCNA, and VEGF localization was investigated using confocal microscopy, immunohistochemistry, and RT-PCR. APN peptide II decreased the relative area of FITC-dextran perfused vessels by 4-fold, PCNA expression by 3-fold, and the number of PCNA stained HUVEC and MAVEC cells by 38 and 46%, respectively. We concluded that APN peptide II inhibits CNV size on days 7 and 14 by inhibiting the proliferation of endothelial cells in vivo and in vitro. APN peptide II may have therapeutic potential to inhibit CNV or wet AMD. PMID:19422927

  16. Arabinosylation Modulates the Growth-Regulating Activity of the Peptide Hormone CLE40a from Soybean.

    PubMed

    Corcilius, Leo; Hastwell, April H; Zhang, Mengbai; Williams, James; Mackay, Joel P; Gresshoff, Peter M; Ferguson, Brett J; Payne, Richard J

    2017-09-08

    Small post-translationally modified peptide hormones mediate crucial developmental and regulatory processes in plants. CLAVATA/ENDOSPERM-SURROUNDING REGION (CLE) genes are found throughout the plant kingdom and encode for 12-13 amino acid peptides that must often undergo post-translational proline hydroxylation and glycosylation with O-β1,2-triarabinose moieties before they become functional. Apart from a few recent examples, a detailed understanding of the structure and function of most CLE hormones is yet to be uncovered. This is mainly owing to difficulties in isolating mature homogeneously modified CLE peptides from natural plant sources. In this study, we describe the efficient synthesis of a synthetic Araf3Hyp glycosylamino acid building block that was used to access a hitherto uninvestigated CLE hormone from soybean called GmCLE40a. Through the development and implementation of a novel in vivo root growth assay, we show that the synthetic triarabinosylated glycopeptide suppresses primary root growth in this important crop species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Temporally controlled release of multiple growth factors from a self-assembling peptide hydrogel

    NASA Astrophysics Data System (ADS)

    Bruggeman, Kiara F.; Rodriguez, Alexandra L.; Parish, Clare L.; Williams, Richard J.; Nisbet, David R.

    2016-09-01

    Protein growth factors have demonstrated great potential for tissue repair, but their inherent instability and large size prevents meaningful presentation to biologically protected nervous tissue. Here, we create a nanofibrous network from a self-assembling peptide (SAP) hydrogel to carry and stabilize the growth factors. We significantly reduced growth factor degradation to increase their lifespan by over 40 times. To control the temporal release profile we covalently attached polysaccharide chitosan molecules to the growth factor to increase its interactions with the hydrogel nanofibers and achieved a 4 h delay, demonstrating the potential of this method to provide temporally controlled growth factor delivery. We also describe release rate based analysis to examine the growth factor delivery in more detail than standard cumulative release profiles allow and show that the chitosan attachment method provided a more consistent release profile with a 60% reduction in fluctuations. To prove the potential of this system as a complex growth factor delivery platform we demonstrate for the first time temporally distinct release of multiple growth factors from a single tissue specific SAP hydrogel: a significant goal in regenerative medicine.

  18. Receptor kinase complex transmits RALF peptide signal to inhibit root growth in Arabidopsis

    PubMed Central

    Du, Changqing; Li, Xiushan; Chen, Jia; Chen, Weijun; Li, Bin; Li, Chiyu; Wang, Long; Li, Jianglin; Zhao, Xiaoying; Lin, Jianzhong; Liu, Xuanming; Luan, Sheng; Yu, Feng

    2016-01-01

    A number of hormones work together to control plant cell growth. Rapid Alkalinization Factor 1 (RALF1), a plant-derived small regulatory peptide, inhibits cell elongation through suppression of rhizosphere acidification in plants. Although a receptor-like kinase, FERONIA (FER), has been shown to act as a receptor for RALF1, the signaling mechanism remains unknown. In this study, we identified a receptor-like cytoplasmic kinase (RPM1-induced protein kinase, RIPK), a plasma membrane-associated member of the RLCK-VII subfamily, that is recruited to the receptor complex through interacting with FER in response to RALF1. RALF1 triggers the phosphorylation of both FER and RIPK in a mutually dependent manner. Genetic analysis of the fer-4 and ripk mutants reveals RIPK, as well as FER, to be required for RALF1 response in roots. The RALF1–FER–RIPK interactions may thus represent a mechanism for peptide signaling in plants. PMID:27930296

  19. Inhibition of primary breast tumor growth and metastasis using a neuropilin-1 transmembrane domain interfering peptide

    PubMed Central

    Arpel, Alexia; Gamper, Coralie; Spenlé, Caroline; Fernandez, Aurore; Jacob, Laurent; Baumlin, Nadège; Laquerriere, Patrice; Orend, Gertraud; Crémel, Gérard; Bagnard, Dominique

    2016-01-01

    The transmembrane domains (TMD) in membrane receptors play a key role in cell signaling. As previously shown by us a peptide targeting the TMD of neuropilin-1 (MTP-NRP1), blocks cell proliferation, cell migration and angiogenesis in vitro, and decreases glioblastoma growth in vivo. We now explored the clinical potential of MTP-NRP1 on breast cancer models and demonstrate that MTP-NRP1 blocks proliferation of several breast cancer lines including the MDA-MB-231, a triple negative human breast cancer cell line. In models with long term in vivo administration of the peptide, MTP-NRP1 not only reduced tumor volume but also decreased number and size of breast cancer metastases. Strikingly, treating mice before tumors developed protected from metastasis establishment/formation. Overall, our results report that targeting the TMD of NRP1 in breast cancer is a potent new strategy to fight against breast cancer and related metastasis. PMID:27351129

  20. Therapeutic effects of cell-permeant peptides that activate G proteins downstream of growth factors

    PubMed Central

    Ma, Gary S.; Aznar, Nicolas; Kalogriopoulos, Nicholas; Midde, Krishna K.; Lopez-Sanchez, Inmaculada; Sato, Emi; Dunkel, Ying; Gallo, Richard L.; Ghosh, Pradipta

    2015-01-01

    In eukaryotes, receptor tyrosine kinases (RTKs) and trimeric G proteins are two major signaling hubs. Signal transduction via trimeric G proteins has long been believed to be triggered exclusively by G protein-coupled receptors (GPCRs). This paradigm has recently been challenged by several studies on a multimodular signal transducer, Gα-Interacting Vesicle associated protein (GIV/Girdin). We recently demonstrated that GIV’s C terminus (CT) serves as a platform for dynamic association of ligand-activated RTKs with Gαi, and for noncanonical transactivation of G proteins. However, exogenous manipulation of this platform has remained beyond reach. Here we developed cell-permeable GIV-CT peptides by fusing a TAT-peptide transduction domain (TAT-PTD) to the minimal modular elements of GIV that are necessary and sufficient for activation of Gi downstream of RTKs, and used them to engineer signaling networks and alter cell behavior. In the presence of an intact GEF motif, TAT-GIV-CT peptides enhanced diverse processes in which GIV’s GEF function has previously been implicated, e.g., 2D cell migration after scratch-wounding, invasion of cancer cells, and finally, myofibroblast activation and collagen production. Furthermore, topical application of TAT-GIV-CT peptides enhanced the complex, multireceptor-driven process of wound repair in mice in a GEF-dependent manner. Thus, TAT-GIV peptides provide a novel and versatile tool to manipulate Gαi activation downstream of growth factors in a diverse array of pathophysiologic conditions. PMID:25926659

  1. Characterization of autoantibodies to vasoactive intestinal peptide in asthma.

    PubMed

    Paul, S; Said, S I; Thompson, A B; Volle, D J; Agrawal, D K; Foda, H; de la Rocha, S

    1989-07-01

    Vasoactive intestinal peptide (VIP) is a potent relaxant of the airway smooth muscle. In this study, VIP-binding autoantibodies were observed in the plasma of 18% asthma patients and 16% healthy subjects. Immunoprecipitation studies and chromatography on DEAE-cellulose and immobilized protein G indicated that the plasma VIP-binding activity was largely due to IgG antibodies. Saturation analysis of VIP binding by the plasmas suggested the presence of one or two classes of autoantibodies, distinguished by their apparent equilibrium affinity constants (Ka). The autoantibodies from asthma patients exhibited a larger VIP-binding affinity compared to those from healthy subjects (Ka 7.8 x 10(9) M-1 and 0.13 x 10(9) M-1, respectively; P less than 0.005). The antibodies were specific for VIP, judged by their poor reaction with peptides bearing partial sequence homology with VIP (peptide histidine isoleucine, growth hormone releasing factor and secretin). IgG prepared from the plasma of an antibody-positive asthma patient inhibited the saturable binding of 125I-VIP by receptors in guinea pig lung membranes (by 39-59%; P less than 0.001). These observations are consistent with a role for the VIP autoantibodies in the airway hyperresponsiveness of asthma.

  2. Calcitonin gene-related peptide (CGRP) stimulates purkinje cell dendrite growth in culture.

    PubMed

    D'Antoni, Simona; Zambusi, Laura; Codazzi, Franca; Zacchetti, Daniele; Grohovaz, Fabio; Provini, Luciano; Catania, Maria Vincenza; Morara, Stefano

    2010-12-01

    Previous reports described the transient expression during development of Calcitonin Gene-Related Peptide (CGRP) in rodent cerebellar climbing fibers and CGRP receptor in astrocytes. Here, mixed cerebellar cultures were used to analyze the effects of CGRP on Purkinje cells growth. Our results show that CGRP stimulated Purkinje cell dendrite growth under cell culture conditions mimicking Purkinje cell development in vivo. The stimulation was not blocked by CGRP8-37, a specific antagonist, suggesting the activation of other related receptors. CGRP did not affect survival of Purkinje cells, granule cells or astrocytes. The selective expression of Receptor Component Protein (RCP) (a component of CGRP receptor family) in astrocytes points to a role of these cells as mediators of CGRP effect. Finally, in pure cerebellar astrocyte cultures CGRP induced a transient morphological differentiation from flat, polygonal to stellate form. It is concluded that CGRP influences Purkinje cell dendrite growth in vitro, most likely through the involvement of astrocytes.

  3. Synthesis and characterization of a peptide nucleic acid conjugated to a D-peptide analog of insulin-like growth factor 1 for increased cellular uptake.

    PubMed

    Basu, S; Wickstrom, E

    1997-01-01

    DNA therapeutics show great potential for gene-specific, nontoxic therapy of a wide variety of diseases. The deoxyribose phosphate backbone of DNA has been modified in a number of ways to improve nuclease stability and cell membrane permeability. Recently, a new DNA derivative with an amide backbone instead of a deoxyribose phosphate backbone, peptide nucleic acid (PNA), has shown tremendous potential as an antisense agent. Although PNAs hybridize very strongly and specifically to RNA and DNA, they are taken up by cells very poorly, limiting their potential as nucleic acid binding agents. To improve cellular uptake of a PNA sequence, it was conjugated to a D-amino acid analog of insulin-like growth factor 1 (IGF1), which binds selectively to the cell surface receptor for insulin-like growth factor 1 (IGF1R). The IGF1 D-peptide analog was assembled on (4-methylbenzhydryl)amine resin, and then the PNA was extended as a continuation of the peptide. The conjugate and control sequences were radiolabeled with 14C or fluorescently labeled with fluorescein isothiocyanate. Cellular uptake of the PNA-peptide conjugate, a control with two alanines in the peptide, and a control PNA without the peptide segment were studied in murine BALB/c 3T3 cells, which express low levels of murine IGF1R, in p6 cells, which are BALB/c 3T3 cells which overexpress a transfected human IGF1R gene, and in human Jurkat cells, which do not express IGF1R, as a negative control. The specific PNA-peptide conjugate displayed much higher uptake than the control PNA, but only in cells expressing IGF1R. This approach may allow cell-specific and tissue-specific application of PNAs as gene-regulating agents in vivo.

  4. Hedgehog signaling activation induces stem cell proliferation and hormone release in the adult pituitary gland

    PubMed Central

    Pyczek, Joanna; Buslei, Rolf; Schult, David; Hölsken, Annett; Buchfelder, Michael; Heß, Ina; Hahn, Heidi; Uhmann, Anja

    2016-01-01

    Hedgehog (HH) signaling is known to be essential during the embryonal development of the pituitary gland but the knowledge about its role in the adult pituitary and in associated tumors is sparse. In this report we investigated the effect of excess Hh signaling activation in murine pituitary explants and analyzed the HH signaling status of human adenopituitary lobes and a large cohort of pituitary adenomas. Our data show that excess Hh signaling led to increased proliferation of Sox2+ and Sox9+ adult pituitary stem cells and to elevated expression levels of adrenocorticotropic hormone (Acth), growth hormone (Gh) and prolactin (Prl) in the adult gland. Inhibition of the pathway by cyclopamine reversed these effects indicating that active Hh signaling positively regulates proliferative processes of adult pituitary stem cells and hormone production in the anterior pituitary. Since hormone producing cells of the adenohypophysis as well as ACTH-, GH- and PRL-immunopositive adenomas express SHH and its target GLI1, we furthermore propose that excess HH signaling is involved in the development/maintenance of hormone-producing pituitary adenomas. These findings advance the understanding of physiological hormone regulation and may open new treatment options for pituitary tumors. PMID:27109116

  5. Fusogenic-oligoarginine peptide-mediated silencing of the CIP2A oncogene suppresses oral cancer tumor growth in vivo.

    PubMed

    Alexander-Bryant, Angela A; Dumitriu, Anca; Attaway, Christopher C; Yu, Hong; Jakymiw, Andrew

    2015-11-28

    Intracellular delivery and endosomal escape of functional small interfering RNAs (siRNAs) remain major barriers limiting the clinical translation of RNA interference (RNAi)-based therapeutics. Recently, we demonstrated that a cell-penetrating endosome-disruptive peptide we synthesized, termed 599, enhanced the intracellular delivery and bioavailability of siRNAs designed to target the CIP2A oncoprotein (siCIP2A) into oral cancer cells and consequently inhibited oral cancer cell invasiveness and anchorage-independent growth in vitro. Thus, to further assess the therapeutic potential of the 599 peptide in mediating RNAi-based therapeutics for oral cancer and its prospective applicability in clinical settings, the objective of the current study was to determine whether intratumoral dosing of the 599 peptide-siCIP2A complex could induce silencing of CIP2A and consequently impair tumor growth using a xenograft oral cancer mouse model. Our results demonstrate that the 599 peptide is able to protect siRNAs from degradation by serum and ribonucleases in vitro and upon intratumoral injection in vivo, confirming the stability of the 599 peptide-siRNA complex and its potential for therapeutic utility. Moreover, 599 peptide-mediated delivery of siCIP2A to tumor tissue induces CIP2A silencing without any associated toxicity, consequently resulting in reduction of the mitotic index and significant inhibition of tumor growth. Together, these data suggest that the 599 peptide carrier is a clinically effective mediator of RNAi-based cancer therapeutics.

  6. Direct evidence of estrogen modulation of pituitary sensitivity to luteinizing hormone-releasing factor during the menstrual cycle.

    PubMed Central

    Wang, C F; Yen, S S

    1975-01-01

    To delineate the role of estradiol in the augmented pituitary gonadotropin responsiveness to synthetic luteinizing hormone releasing factor (LRF) seen during high-estrogen phases of the ovulatory cycles (late follicular and midluteal phases), the anti-estrogenic effect of clomiphene citrate (Clomid) on pituitary response to LRF was evaluated during different phases of the ovulatory cycle. Clomid administration (100 mg/day times 5 days) completely negates the augmented gonadotropin responses to LRF (150 mug) during late follicular and midluteal phases observed during the control studies. Thus, a quantitatively and qualitatively similar pituitary sensitivity to LRF during three distinct phases of the menstrual cycle was induced by Clomid treatment that resembles the LRF responsiveness of themale pituitary. The present study demonstrates the pituitary component of the estrogen-induced changes in the sensitivity to LRF. From this and previous data, we conclude that the increases of estradiol secretion associated with the follicular maturation and corpus luteum formation represent a major component of the feedback signal in the modulation of cyclic gonadotropin release occasioned in a large measure by the augmented pituitary sensitivity to LRF. PMID:1088908

  7. Acute Effect of Manganese on Hypothalamic Luteinizing Hormone Releasing Hormone Secretion in Adult Male Rats: Involvement of Specific Neurotransmitter Systems

    PubMed Central

    Prestifilippo, Juan Pablo; Fernández-Solari, Javier; De Laurentiis, Andrea; Mohn, Claudia Ester; de la Cal, Carolina; Reynoso, Roxana; Dees, W. Les; Rettori, Valeria

    2008-01-01

    Manganese chloride (MnCl2) is capable of stimulating luteinizing hormone releasing hormone (LHRH) secretion in adult male Sprague-Dawley rats through the activation of the hypothalamic nitric oxide/cyclic guanosine monophosphate (cGMP)/protein kinase G pathway. The present study aimed to determine the involvement of specific neurotransmitters involved in this action. Our results indicate that dopamine, but not glutamic acid and prostaglandinds, mediates the MnCl2 stimulated secretion of LHRH from medial basal hypothalami in vitro, as well as increases the activity of nitric oxide synthase. Furthermore, a biphasic response was observed in that gamma aminobutyric acid (GABA) release was also increased, which acts to attenuate the MnCl2 action to stimulate LHRH secretion. Although it is clear that manganese (Mn+2) can acutely induce LHRH secretion in adult males, we suggest that the additional action of MnCl2 to release GABA, a LHRH inhibitor, may ultimately contribute to suppressed reproductive function observed in adult animals following exposure to high chromic levels of Mn+2. PMID:18603625

  8. Is radiation-induced ovarian failure in rhesus monkeys preventable by luteinizing hormone-releasing hormone agonists?: Preliminary observations

    SciTech Connect

    Ataya, K.; Pydyn, E.; Ramahi-Ataya

    1995-03-01

    With the advent of cancer therapy, increasing numbers of cancer patients are achieving long term survival. Impaired ovarian function after radiation therapy has been reported in several studies. Some investigators have suggested that luteinizing hormone-releasing hormone agonists (LHRHa) can prevent radiation-induced ovarian injury in rodents. Adult female rhesus monkeys were given either vehicle or Leuprolide acetate before, during, and after radiation. Radiation was given in a dose of 200 rads/day for a total of 4000 rads to the ovaries. Frequent serum samples were assayed for estradiol (E{sub 2}) and FSH. Ovariectomy was performed later. Ovaries were processed and serially sectioned. Follicle count and size distribution were determined. Shortly after radiation started, E{sub 2} dropped to low levels, at which it remained, whereas serum FSH level, which was low before radiation, rose soon after starting radiation. In monkeys treated with a combination of LHRHa and radiation, FSH started rising soon after the LHRHa-loaded minipump was removed (after the end of radiation). Serum E{sub 2} increased after the end of LHRHa treatment in the non-irradiated monkey, but not in the irradiated monkey. Follicle counts were not preserved in the LHRHa-treated monkeys that received radiation. The data demonstrated no protective effect of LHRHa treatment against radiation-induced ovarian injury in this rhesus monkey model. 58 refs., 2 figs., 1 tab.

  9. Menstruation recovery after chemotherapy and luteinizing hormone-releasing hormone agonist plus tamoxifen therapy for premenopausal patients with breast cancer.

    PubMed

    Sakurai, Kenichi; Matsuo, Sadanori; Enomoto, Katsuhisa; Amano, Sadao; Shiono, Motomi

    2011-01-01

    Little is known about the period required for menstruation recovery after long-term luteinizing hormone-releasing hormone (LH-RH) agonist plus tamoxifen therapy following chemotherapy. In this study we investigated the period required for menstruation recovery after the therapy. The subjects comprised 105 premenopausal breast cancer patients who had undergone surgery. All patients were administered an LH-RH agonist for 24 months and tamoxifen for 5 years following the postoperative adjuvant chemotherapy, and the status of menstruation recovery was examined. Menstruation resumed in 16 cases (15.2%) after the last LH-RH agonist treatment session. The mean period from the last LH-RH agonist treatment to the recovery of menstruation was 6.9 months. The rate of menstruation recovery was 35.5% in patients aged 40 years or younger and 8.0% in those aged 41 years or older, and it was significantly higher in those aged 40 years or younger. The period until menstruation recovery tended to be longer in older patients at the end of treatment. This study showed that menstruation resumed after treatment at higher rates in younger patients. However, because it is highly likely that ovarian function will be destroyed by the treatment even in young patients, it is considered necessary to explain the risk to patients and obtain informed consent before introducing this treatment modality.

  10. Aging influences steroid hormone release by mink ovaries and their response to leptin and IGF-I.

    PubMed

    Sirotkin, Alexander V; Mertin, Dušan; Süvegová, Karin; Harrath, Abdel Halim; Kotwica, Jan

    2016-01-21

    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.

  11. 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

  12. Effects of a growth hormone-releasing hormone analog on endogenous GH pulsatility and insulin sensitivity in healthy men.

    PubMed

    Stanley, Takara L; Chen, Cindy Y; Branch, Karen L; Makimura, Hideo; Grinspoon, Steven K

    2011-01-01

    Strategies to augment pulsatile GH may be beneficial in patients with excess visceral adiposity, in whom GH secretion is reduced. The objective of this study was to determine the effects of a novel GHRH (GHRH(1-44)) analog, tesamorelin, on endogenous GH pulsatility and insulin sensitivity in healthy men. Thirteen males (mean age 45 ± 3 yr and body mass index 27.3 ± 1.2 kg/m(2)) received tesamorelin 2 mg sc once daily for 2 wk, with assessment made at baseline, after 2 wk of treatment, and after 2 wk of withdrawal. The primary end point was change in mean overnight GH as determined by overnight frequent sampling. Secondary end points included insulin-stimulated glucose uptake as measured by euglycemic hyperinsulinemic clamp; IGF-I; and GH secretion parameters, including pulse area, pulse frequency, and basal secretion. Tesamorelin treatment increased mean overnight GH (change +0.5 ± 0.1 μg/liter, P = 0.004), average log(10) GH peak area (change +0.4 ± 0.1 log(10) μg/liter, P = 0.001), and basal GH secretion (change +0.008 ± 0.003 μg/liter · min, P = 0.008). IGF-I increased by 181 ± 22 μg/liter (P < 0.0001). Neither fasting glucose (P = 0.93) nor insulin-stimulated glucose uptake (P = 0.61) was significantly affected by tesamorelin. Once-daily short-term treatment with a GHRH(1-44) analog, tesamorelin, augments basal and pulsatile GH secretion. Moreover, although tesamorelin significantly increases IGF-I, peripheral insulin-stimulated glucose uptake appears to be preserved.

  13. Cortistatin inhibits growth hormone release from human fetal and adenoma pituitary cells and prolactin secretion from cultured prolactinomas.

    PubMed

    Rubinfeld, Hadara; Hadani, Moshe; Barkai, Gad; Taylor, John E; Culler, Michael D; Shimon, Ilan

    2006-06-01

    Cortistatin (CST) is a neuropeptide that shares high homology with somatostatin and binds with high affinity to all somatostatin receptor (SSTR) subtypes. Many of its endocrine and biological activities overlap with those of somatostatin. The objective of the study was to assess the direct in vitro effects of CST on human pituitary hormone secretion. This study was performed in the endocrine laboratory of a tertiary academic medical center. Primary cell cultures of human fetal (21-25 wk gestation) pituitary tissues and cultured hormone-secreting adenoma cells were used in this study. Cell cultures were incubated with CST-14 or CST-17, somatostatin, GHRH, SSTR analogs, and ghrelin analogs, and hormone secretion was analyzed. GH and prolactin (PRL) medium concentrations were tested by hormone assay, and SSTR mRNA was tested by RT-PCR. CST-14 (10 nm) inhibited GH secretion by up to 65% in all fetal pituitary specimens after 4-h incubation (P < 0.05). CST-14 or CST-17 (10 nm) inhibited basal GH secretion in six of the 13 GH-cell adenomas and two of the three GH-PRL mixed adenomas. CST-17 (100 nm) suppressed the GH response to GHRH and ghrelin analog (10 nm each) by 30-50% in adenomas (P < 0.05). Three PRL-adenomas treated with CST-17 (10 nm) showed a 20-40% inhibition of PRL release (P < 0.05), whereas in three others no suppression or mild response was achieved at this concentration. A comparable inhibition of PRL secretion was obtained with SSTR5-selective analog but significantly less with SSTR2-preferential compounds. RT-PCR revealed the expression of both SSTR2 and SSTR5 in all GH-cell and mixed adenomas studied and all PRL-secreting adenomas studied, except for two of the CST-resistant prolactinomas, in which SSTR5 was absent. This is the first report of in vitro CST suppression of human GH and PRL in cultured pituitary tissues. The regulation of PRL release from cultured adenomas appears to be primarily mediated by SSTR5.

  14. Heterozygous gsp mutation renders ion channels of human somatotroph adenoma cells unresponsive to growth hormone-releasing hormone.

    PubMed

    Yasufuku-Takano, J; Takano, K; Takei, T; Fukumoto, S; Teramoto, A; Takakura, K; Yamashita, N; Fujita, T

    1999-05-01

    Ionic mechanisms play an important role in the regulation of hormone secretion. The GHRH-induced GH release by human GH-secreting cells is transmitted through protein kinase A (PKA), which activates nonselective cation current (NSCC) and induces membrane depolarization, intracellular Ca2+ increase, and GH secretion. To evaluate whether ionic mechanisms have pathophysiological significance in GH oversecretion of GH-secreting pituitary adenomas, we examined four adenomas with constitutively active Gs alpha mutation (gsp mutation) and compared with three gsp-negative adenomas. In primary-cultured cells of gsp-positive adenomas, GHRH did not increase the NSCC under voltage-clamp experiments. Detailed examination showed that NSCC was maximally activated at the basal level and application of GHRH did not increase the current in these adenomas. Furthermore, by using single-cell RT-PCR method, we demonstrated for the first time at the single cell level that gsp mutation is heterozygous in GH-secreting pituitary adenomas. These indicate that heterozygous gsp mutation fully activates NSCC at the basal level, which may account for the GH oversecretion in gsp-positive GH-secreting pituitary adenomas.

  15. Growth hormone-releasing hormone resistance in pseudohypoparathyroidism type ia: new evidence for imprinting of the Gs alpha gene.

    PubMed

    Mantovani, Giovanna; Maghnie, Mohamad; Weber, Giovanna; De Menis, Ernesto; Brunelli, Valeria; Cappa, Marco; Loli, Paola; Beck-Peccoz, Paolo; Spada, Anna

    2003-09-01

    Heterozygous inactivating mutations in the Gs alpha gene cause Albright's hereditary osteodystrophy. Consistent with the observation that only maternally inherited mutations lead to resistance to hormone action [pseudohypoparathyroidism type Ia (PHP Ia)], recent studies provided evidence for a predominant maternal origin of Gs alpha transcripts in endocrine organs, such as thyroid, gonad, and pituitary. The aim of this study was to investigate the presence of pituitary resistance to hypothalamic hormones acting via Gs alpha-coupled receptors in patients with PHP Ia. Six of nine patients showed an impaired GH responsiveness to GHRH plus arginine, consistent with a complete GH deficiency (GH peak from 2.6-8.6 microg/liter, normal > 16.5), and partial (GH peak 13.9 and 13.6 microg/liter) and normal responses were found in two and one patient, respectively. Accordingly, IGF-I levels were below and in the low-normal range in seven and two patients. All patients had a normal cortisol response to 1 microg ACTH test, suggesting a normal corticotroph function that was confirmed by a normal ACTH and cortisol response to CRH test in three patients. In conclusion, we report that in addition to PTH and TSH resistance, patients with PHP Ia display variable degrees of GHRH resistance, consistent with Gs alpha imprinting in human pituitary.

  16. The rat growth hormone-releasing hormone receptor gene: structure, regulation, and generation of receptor isoforms with different signaling properties.

    PubMed

    Miller, T L; Godfrey, P A; Dealmeida, V I; Mayo, K E

    1999-09-01

    The interaction of GHRH with membrane-bound receptors on somatotroph cells of the anterior pituitary is an important step in the regulation of GH synthesis and secretion. The identification of a G protein-coupled receptor for GHRH has made it possible to investigate the pathway by which GHRH regulates pituitary somatotroph cell function. To initiate an analysis of the mechanisms regulating expression and function of the GHRH receptor, the structure of the gene and its promoter region were analyzed. The coding sequence of the rat GHRH receptor gene is contained within 14 exons spanning approximately 15 kb of genomic DNA. Four transcription start sites are located within 286 bp upstream of the initiation codon. The 5' flanking region of the GHRH receptor gene acts as a functional promoter in rat pituitary tumor GH3 cells, and basal promoter activity is enhanced in GH3 and COS7 cells by cotransfection of an expression construct encoding the pituitary-specific transcription factor Pit-1. The rat GHRH receptor gene is subject to at least 1 alternative RNA processing event that generates 2 receptor isoforms differing by 41 amino acids within the third intracellular loop (IL) of the protein. The short isoform of the GHRH receptor is predominant in pituitary cells. The MtT/S pituitary tumor cell line was found to express the GHRH receptor, and different populations of these cells produce predominantly the long or short isoforms of the receptor messenger RNA, suggesting that the alternative splicing can be regulated. Functional analysis of the two GHRH receptor isoforms demonstrates that both bind GHRH, but only the short isoform signals through a cAMP-mediated pathway. Neither receptor isoform is able to stimulate calcium mobilization from internal stores after GHRH treatment. Our findings indicate that the pituitary-specific transcription factor Pit-1 is involved in the somatotroph-specific expression of the GHRH receptor gene and that functionally distinct receptor proteins are generated by an alternative RNA processing mechanism.

  17. Effects of growth hormone-releasing hormone on visceral fat, metabolic, and cardiovascular indices in human studies.

    PubMed

    Stanley, Takara L; Grinspoon, Steven K

    2015-04-01

    Increased visceral adipose tissue (VAT) is associated with reductions in endogenous GH secretion, possibly as a result of hyperinsulinemia, increased circulating free fatty acid, increased somatostatin tone, and reduced ghrelin. Reduced GH may, in turn, further exacerbate visceral fat accumulation because of decreased hormone-sensitive lipolysis in this depot. Data from multiple populations demonstrate that both reduced GH and increased VAT appear to contribute independently to dyslipidemia, increased systemic inflammation, and increased cardiovascular risk. The reductions in GH in states of visceral adiposity are characterized by reduced basal and pulsatile GH secretion with intact pulse frequency. Treatment with GH-releasing hormone (GHRH) provides a means to reverse these abnormalities, increasing endogenous basal and pulsatile GH secretion without altering pulse frequency. This review describes data from HIV-infected individuals and individuals with general obesity showing that treatment with GHRH significantly reduces visceral fat, ameliorates dyslipidemia, and reduces markers of cardiovascular risk. Further research is needed regarding the long-term efficacy and safety of this treatment modality. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Growth hormone-releasing hormone (GRH)-producing pancreatic tumor with no evidence of multiple endocrine neoplasia type 1.

    PubMed

    Kawa, S; Ueno, T; Iijima, A; Midorikawa, T; Fujimori, Y; Tokoo, M; Oguchi, H; Kiyosawa, K; Imai, Y; Kaneko, G; Kuroda, T; Hashizume, K; Osamura, R Y; Katakami, H

    1997-07-01

    The characteristic features of a 48-year-old male presenting with isolated acromegaly caused by a GRH-producing pancreatic endocrine tumor bearing no relation to MEN1 was reported. The clinical features, laboratory findings, and sellar enlargement were improved after removal of the pancreatic tumor. The resected pancreatic tumor showed positive GRH immunoreactivity and contained abundant GRH mRNA. This tumor is extremely rare and to date only 10 cases have been reported. In the management of acromegaly, the measurement of GRH is recommended and the search for an ectopic source will prevent unnecessary and potentially ineffective pituitary surgery.

  19. Neither bST nor Growth Hormone Releasing Factor Alter Expression of Thyroid Hormone Receptors in Liver and Mammary Tissues

    USDA-ARS?s Scientific Manuscript database

    Physiological effects of thyroid hormones are mediated primarily by binding of triiodothyronine, to specific nuclear receptors. It has been hypothesized that organ-specific changes in production of triiodothyronine from its prohormone, thyroxine, target the action of thyroid hormones to the mammary...

  20. Circadian and sleep-dependent regulation of hormone release in humans

    NASA Technical Reports Server (NTRS)

    Czeisler, C. A.; Klerman, E. B.

    1999-01-01

    Daily oscillations characterize the release of nearly every hormone. The circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, generates circadian, approximately 24-hour rhythms in many physiologic functions. However, the observed hormonal oscillations do not simply reflect the output of this internal clock. Instead, daily hormonal profiles are the product of a complex interaction between the output of the circadian pacemaker, periodic changes in behavior, light exposure, neuroendocrine feedback mechanisms, gender, age, and the timing of sleep and wakefulness. The interaction of these factors can affect hormonal secretory pulse frequency and amplitude, with each endocrine system differentially affected by these factors. This chapter examines recent advances in understanding the effects on endocrine rhythms of a number of these factors. Sleep exerts a profound effect on endocrine secretion. Sleep is a dynamic process that is characterized by periodic changes in electrophysiologic activity. These electrophysiologic changes, which are used to mark the state and depth of sleep, are associated with periodic, short-term variations in hormonal levels. The secretion of hormones such as renin and human growth hormone are strongly influenced by sleep or wake state, while melatonin and cortisol levels are relatively unaffected by sleep or wake state. In addition, sleep is associated with changes in posture, behavior, and light exposure, each of which is known to affect endocrine secretion. Furthermore, the tight concordance of habitual sleep and wake times with certain circadian phases has made it difficult to distinguish sleep and circadian effects on these hormones. Specific protocols, designed to extract circadian and sleep information semi-independently, have been developed and have yielded important insights into the effects of these regulatory processes. These results may help to account for changes in endocrine rhythms observed in circadian

  1. Cancer cell-binding peptide fused Fc domain activates immune effector cells and blocks tumor growth

    PubMed Central

    Mobergslien, Anne; Peng, Qian; Vasovic, Vlada; Sioud, Mouldy

    2016-01-01

    Therapeutic strategies aiming at mobilizing immune effector cells to kill tumor cells independent of tumor mutational load and MHC expression status are expected to benefit cancer patients. Recently, we engineered various peptide-Fc fusion proteins for directing Fcg receptor-bearing immune cells toward tumor cells. Here, we investigated the immunostimulatory and anti-tumor effects of one of the engineered Fc fusion proteins (WN-Fc). In contrast to the Fc control, soluble WN-Fc-1 fusion protein activated innate immune cells (e.g. monocytes, macrophages, dendritic cells, NK cells), resulting in cytokine production and surface display of the lytic granule marker CD107a on NK cells. An engineered Fc-fusion variant carrying two peptide sequences (WN-Fc-2) also activated immune cells and bound to various cancer cell types with high affinity, including the murine 4T1 breast carcinoma cells. When injected into 4T1 tumor-bearing BALB/c mice, both peptide-Fc fusions accumulated in tumor tissues as compared to other organs such as the lungs. Moreover, treatment of 4T1 tumor-bearing BALB/c mice by means of two intravenous injections of the WN-Fc fusion proteins inhibited tumor growth with WN-Fc-2 being more effective than WN-Fc-1. Treatment resulted in tumor infiltration by T cells and NK cells. These new engineered WN-Fc fusion proteins may be a promising alternative to existing immunotherapies for cancer. PMID:27713158

  2. Histone H4-related osteogenic growth peptide (OGP): a novel circulating stimulator of osteoblastic activity.

    PubMed Central

    Bab, I; Gazit, D; Chorev, M; Muhlrad, A; Shteyer, A; Greenberg, Z; Namdar, M; Kahn, A

    1992-01-01

    It has been established that regenerating marrow induces an osteogenic response in distant skeletal sites and that this activity is mediated by factors released into the circulation by the healing tissue. In the present study we have characterized one of these factors, a 14 amino acid peptide named osteogenic growth peptide (OGP). Synthetic OGP, identical in structure to the native molecule, stimulates the proliferation and alkaline phosphatase activity of osteoblastic cells in vitro and increases bone mass in rats when injected in vivo. Immunoreactive OGP in high abundance is present physiologically in the serum, mainly in the form of an OGP-OGP binding protein complex. A marked increase in serum bound and unbound OGP accompanies the osteogenic phase of post-ablation marrow regeneration and associated systemic osteogenic response. Authentic OGP is identical to the C-terminus of histone H4 and shares a five residue motif with a T-cell receptor beta-chain V-region and the Bacillus subtilis outB locus. Since these latter proteins have not been implicated previously in the control of cell proliferation or differentiation, OGP may belong to a novel, heretofore unrecognized family of regulatory peptides. Perhaps more importantly, OGP appears to represent a new class of molecules involved in the systemic control of osteoblast proliferation and differentiation. Images PMID:1582415

  3. Phthalocyanine-Peptide Conjugates for Epidermal Growth Factor Receptor Targeting1

    PubMed Central

    Ongarora, Benson G.; Fontenot, Krystal R.; Hu, Xiaoke; Sehgal, Inder; Satyanarayana-Jois, Seetharama D.; Vicente, M. Graça H.

    2012-01-01

    Four phthalocyanine (Pc)-peptide conjugates designed to target the epidermal growth factor receptor (EGFR) were synthesized and evaluated in vitro using four cell lines: human carcinoma A431 and HEp2, human colorectal HT-29, and kidney Vero (negative control) cells. Two peptide ligands for EGFR were investigated: EGFR-L1 and -L2, bearing 6 and 13 amino acid residues, respectively. The peptides and Pc-conjugates were shown to bind to EGFR using both theoretical (Autodock) and experimental (SPR) investigations. The Pc-EGFR-L1 conjugates 5a and 5b efficiently targeted EGFR and were internalized, in part due to their cationic charge, whereas the uncharged Pc-EGFR-L2 conjugates 4b and 6a poorly targeted EGFR maybe due to their low aqueous solubility. All conjugates were non-toxic (IC50 > 100 µM) to HT-29 cells, both in the dark and upon light activation (1 J/cm2). Intravenous (iv) administration of conjugate 5b into nude mice bearing A431 and HT-29 human tumor xenografts resulted in a near-IR fluorescence signal at ca. 700 nm, 24 h after administration. Our studies show that Pc-EGFR-L1 conjugates are promising near-IR fluorescent contrast agents for CRC, and potentially other EGFR over-expressing cancers. PMID:22468711

  4. A 16-amino acid peptide from human alpha2-macroglobulin binds transforming growth factor-beta and platelet-derived growth factor-BB.

    PubMed Central

    Webb, D. J.; Roadcap, D. W.; Dhakephalkar, A.; Gonias, S. L.

    2000-01-01

    Alpha2-macroglobulin (alpha2M) is a major carrier of transforming growth factor-beta (TGF-beta) in vitro and in vivo. By screening glutathione S-transferase (GST) fusion proteins with overlapping sequences, we localized the TGFbeta-binding site to aa 700-738 of the mature human alpha2M subunit. In separate experiments, we screened overlapping synthetic peptides corresponding to aa 696-777 of alpha2M and identified a single 16-mer (718-733) that binds TGF-beta1. Platelet-derived growth factor-BB (PDGF-BB) bound to the same peptide, even though TGF-beta and PDGF-BB share almost no sequence identity. The sequence of the growth factor-binding peptide, WDLVVVNSAGVAEVGV, included a high proportion of hydrophobic amino acids. The analogous peptide from murinoglobulin, a human alpha2M homologue that does not bind growth factors, contained only three nonconservative amino acid substitutions; however, the MUG peptide failed to bind TGF-beta1 and PDGF-BB. These results demonstrate that a distinct and highly-restricted site in alpha2M, positioned near the C-terminal flank of the bait region, mediates growth factor binding. At least part of the growth factor-binding site is encoded by exon 18 of the alpha2M gene, which is notable for a 5' splice site polymorphism that has been implicated in Alzheimer's Disease. PMID:11106172

  5. Multiple antigen peptide dendrimer elicits antibodies for detecting rat and mouse growth hormone binding proteins

    PubMed Central

    Aguilar, Roberto M.; Talamantes, Frank J.; Bustamante, Juan J.; Muñoz, Jesus; Treviño, Lisa R.; Martinez, Andrew O.; Haro, Luis S.

    2009-01-01

    The membrane-bound rat growth hormone receptor (GH-R) and an alternatively spliced isoform, the soluble rat GH binding protein (GH-BP), are comprised of identical N-terminal GH binding domains, however, their C-terminal sequences differ. Immunological reagents are needed to distinguish between the two isoforms in order to understand their respective roles in mediating the actions of GH. Accordingly, a tetravalent multiple antigen peptide (MAP) dendrimer with four identical branches of a C-terminal peptide sequence of the rat GH-BP (GH-BP263-279) was synthesized and used as an immunogen in rabbits. Solid-phase peptide synthesis of four GH-BP263-279 segments onto a tetravalent Lys2-Lys-β-Ala-OH core peptide was carried out using N-(9-fluorenyl)methoxycarbonyl chemistry. The mass of the RP-HPLC purified synthetic product, 8398 Da, determined by ESI-MS, was identical to expected mass. Three anti-rat GH-BP263-279 MAP antisera, BETO-8039, BETO-8040 and BETO-8041, at dilutions of 10-3, recognized both the rat GH-BP263-279 MAP and recombinant mouse GH-BP with ED50s within a range of 5-10 fmol but did not cross-react with BSA in dot blot analyses. BETO-8041 antisera (10-3 dilution) recognized GH-BPs of rat serum and liver having Mrs ranging from 35-130 kDa but did not recognize full-length rat GH-Rs. The antisera also detected recombinant mouse GH-BPs. In summary, the tetravalent rat GH-BP263-279 MAP dendrimer served as an effective immunogenic antigen in eliciting high titer antisera specific for the C-termini of both rat and mouse GH-BPs. The antisera will facilitate studies aimed at improving our understanding of the biology of GH-BPs. PMID:19089805

  6. Combination of long-acting microcapsules of the D-tryptophan-6 analog of luteinizing hormone-releasing hormone with chemotherapy: investigation in the rat prostate cancer model.

    PubMed Central

    Schally, A V; Redding, T W

    1985-01-01

    The effect of combining hormonal treatment consisting of long-acting microcapsules of the agonist [D-Trp6]LH-RH (the D-tryptophan-6 analog of luteinizing hormone-releasing hormone) with the chemotherapeutic agent cyclophosphamide was investigated in the Dunning R-3327H rat prostate cancer model. Microcapsules of [D-Trp6]LH-RH formulated from poly(DL-lactide-co-glycolide) and calculated to release a controlled dose of 25 micrograms/day were injected intramuscularly once a month. Cyclophosphamide (Cytoxan) (5 mg/kg of body weight) was injected intraperitoneally twice a week. When the therapy was started 90 days after tumor transplantation--at the time that the cancers were well developed-and was continued for 2 months, tumor volume was significantly reduced by the microcapsules or Cytoxan given alone. The combination of these two agents similarly inhibited tumor growth but did not show a synergistic effect. In another study, the treatment was started 2 months after transplantation, when the developing tumors measured 60-70 mm3. Throughout the treatment period of 100 days, the microcapsules of [D-Trp6]LH-RH reduced tumor volume more than Cytoxan did, and the combination of the two drugs appeared to completely arrest tumor growth. Tumor weights also were diminished significantly in all experimental groups, the decrease in weight being smaller in the Cytoxan-treated group than in rats that received the microcapsules. The combination of Cytoxan plus the microcapsules was 10-100 times more effective than the single agents in reducing tumor weights. In both experiments, testes and ventral prostate weights were significantly diminished, serum testosterone was suppressed to undetectable levels, and prolactin values were reduced by administration of microcapsules of [D-Trp6]LH-RH alone or in combination with Cytoxan. These results in rats suggest that combined administration of long acting microcapsules of [D-Trp6]LH-RH with a chemotherapeutic agent, started soon after the

  7. Growth factors and hormones pro-peptides: the unexpected adventures of the BDNF prodomain.

    PubMed

    Zanin, Juan Pablo; Unsain, Nicolás; Anastasia, Agustin

    2017-05-01

    Most growth factors and hormones are synthesized as pre-pro-proteins which are processed to the biologically active mature protein. The pre- and prodomains are cleaved from the precursor protein in the secretory pathway or, in some cases, extracellularly. The canonical functions of these prodomains are to assist in folding and stabilization of the mature domain, to direct intra and extracellular localization, to facilitate storage, and to regulate bioavailability of their mature counterpart. Recently, exciting evidence has revealed that prodomains of certain growth factors, after cleaved from the precursor pro-protein, can act as independent active signaling molecules. In this review, we discuss the various classical functions of prodomains, and the biological consequences of these pro-peptides acting as ligands. We will focus our attention on the brain-derived neurotrophic factor prodomain (pBDNF), which has been recently described as a novel secreted ligand influencing neuronal morphology and physiology. © 2017 International Society for Neurochemistry.

  8. Accelerated bone growth in vitro by the conjugation of BMP2 peptide with hydroxyapatite on titanium alloy.

    PubMed

    Cai, Yanli; Wang, Xiaoyan; Poh, Chye Khoon; Tan, Hark Chuan; Soe, Min Tun; Zhang, Sam; Wang, Wilson

    2014-04-01

    Titanium alloys have been widely used in orthopedic practice due to their inherent bioactivity, however it is still insufficient to truly and reliably incorporate into living bone. In this work, polydopamine film was employed to induce the growth of hydroxyapatite (HA) on titanium alloy to enhance its osteoconductivity. Bone morphogenetic protein-2 (BMP2) peptide was absorbed into the HA particles for osteoinductivity. The precipitation of HA and the existence of BMP2 peptide were examined by X-ray diffraction, X-ray photoelectron spectroscopy and fluorescence microscopy. The dissolution of HA and the release of BMP2 peptide were monitored by measuring the concentrations of calcium ions and BMP2 peptide in phosphate buffered saline solution, respectively. The effect of BMP2 peptide incorporated into HA coating on bone growth was evaluated in vitro by cell culture tests, including cell attachment, alkaline phosphatase (ALP) activity, and gene expression. The results show that the HA particles grown on the substrate are mediated by the polydopamine film. The BMP2 peptide is distributed uniformly on HA-coated substrate and released in a sustained manner. Moreover, the conjunction of HA and BMP2 peptide increases cell adhesion, ALP activity and gene expression of osteogenic markers, which are potentially useful in the development of enhanced orthopedic medical devices. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Influence of macrocyclization on allosteric, juxtamembrane-derived, stapled peptide inhibitors of the epidermal growth factor receptor (EGFR).

    PubMed

    Sinclair, Julie K-L; Schepartz, Alanna

    2014-09-19

    The hydrocarbon-stapled peptide E1(S) allosterically inhibits the kinase activity of the epidermal growth factor receptor (EGFR) by blocking a distant but essential protein-protein interaction: a coiled coil formed from the juxtamembrane segment (JM) of each member of the dimeric partnership.1 Macrocyclization is not required for activity: the analogous unstapled (but alkene-bearing) peptide is equipotent in cell viability, immunoblot, and bipartite display experiments to detect coiled coil formation on the cell surface.

  10. Iron oxide nanoparticles induce Pseudomonas aeruginosa growth, induce biofilm formation, and inhibit antimicrobial peptide function.

    PubMed

    Borcherding, Jennifer; Baltrusaitis, Jonas; Chen, Haihan; Stebounova, Larissa; Wu, Chia-Ming; Rubasinghege, Gayan; Mudunkotuwa, Imali A; Caraballo, Juan Carlos; Zabner, Joseph; Grassian, Vicki H; Comellas, Alejandro P

    2014-04-01

    Given the increased use of iron-containing nanoparticles in a number of applications, it is important to understand any effects that iron-containing nanoparticles can have on the environment and human health. Since iron concentrations are extremely low in body fluids, there is potential that iron-containing nanoparticles may influence the ability of bacteria to scavenge iron for growth, affect virulence and inhibit antimicrobial peptide (AMP) function. In this study, Pseudomonas aeruginosa (PA01) and AMPs were exposed to iron oxide nanoparticles, hematite (α-Fe2O3), of different sizes ranging from 2 to 540 nm (2 ± 1, 43 ± 6, 85 ± 25 and 540 ± 90 nm) in diameter. Here we show that the greatest effect on bacterial growth, biofilm formation, and AMP function impairment is found when exposed to the smallest particles. These results are attributed in large part to enhanced dissolution observed for the smallest particles and an increase in the amount of bioavailable iron. Furthermore, AMP function can be additionally impaired by adsorption onto nanoparticle surfaces. In particular, lysozyme readily adsorbs onto the nanoparticle surface which can lead to loss of peptide activity. Thus, this current study shows that co-exposure of nanoparticles and known pathogens can impact host innate immunity. Therefore, it is important that future studies be designed to further understand these types of impacts.

  11. Specific Adsorption via Peptide Tags: Oriented Grafting and Release of Growth Factors for Tissue Engineering.

    PubMed

    Murschel, Frederic; Zaimi, Aldo; Noel, Samantha; Jolicoeur, Mario; De Crescenzo, Gregory

    2015-11-09

    Numerous strategies have been proposed to decorate biomaterials with growth factors (GFs) for tissue engineering applications; their practicability as clinical tools, however, remains uncertain. We previously presented two complementary amphipathic peptides, namely, E5 and K5, which could be utilized as tags to direct GF capture onto organic materials via E5/K5 coiled-coil interactions. We here investigated their potential as mediators of GF physical adsorption. Enzyme-linked immunosorbent assays highlighted that both electrostatic and hydrophobic interactions could contribute to the adsorption process, without interfering with the peptides propensity for coiled-coil interactions. E5-tagged vascular endothelial growth factor, in particular, was efficiently adsorbed to poly(allylamine)-functionalized polystyrene, was maintained in a bioactive state and was steadily liberated over several days with little initial burst. This simple immobilization procedure was successfully applied to poly(ethylene terephthalate) films. Altogether, our data demonstrated that coil-tag-directed adsorption is a tunable, versatile and straightforward strategy to decorate biomaterials with GFs.

  12. Iron oxide nanoparticles induce Pseudomonas aeruginosa growth, induce biofilm formation, and inhibit antimicrobial peptide function†

    PubMed Central

    Borcherding, Jennifer; Baltrusaitis, Jonas; Chen, Haihan; Stebounova, Larissa; Wu, Chia-Ming; Rubasinghege, Gayan; Mudunkotuwa, Imali A.; Caraballo, Juan Carlos; Zabner, Joseph

    2014-01-01

    Given the increased use of iron-containing nanoparticles in a number of applications, it is important to understand any effects that iron-containing nanoparticles can have on the environment and human health. Since iron concentrations are extremely low in body fluids, there is potential that iron-containing nanoparticles may influence the ability of bacteria to scavenge iron for growth, affect virulence and inhibit antimicrobial peptide (AMP) function. In this study, Pseudomonas aeruginosa (PA01) and AMPs were exposed to iron oxide nanoparticles, hematite (α-Fe2O3), of different sizes ranging from 2 to 540 nm (2 ± 1, 43 ± 6, 85 ± 25 and 540 ± 90 nm) in diameter. Here we show that the greatest effect on bacterial growth, biofilm formation, and AMP function impairment is found when exposed to the smallest particles. These results are attributed in large part to enhanced dissolution observed for the smallest particles and an increase in the amount of bioavailable iron. Furthermore, AMP function can be additionally impaired by adsorption onto nanoparticle surfaces. In particular, lysozyme readily adsorbs onto the nanoparticle surface which can lead to loss of peptide activity. Thus, this current study shows that co-exposure of nanoparticles and known pathogens can impact host innate immunity. Therefore, it is important that future studies be designed to further understand these types of impacts. PMID:25221673

  13. Beta hairpin peptide hydrogels as an injectable solid vehicle for neurotrophic growth factor delivery

    PubMed Central

    Lindsey, Stephan; Piatt, Joseph H.; Worthington, Peter; Sönmez, Cem; Satheye, Sameer; Schneider, Joel P.; Pochan, Darrin J.; Langhans, Sigrid A.

    2016-01-01

    There is intense interest in developing novel methods for the sustained delivery of low levels of clinical therapeutics. MAX8 is a peptide-based beta-hairpin hydrogel that has unique shear thinning properties that allow for immediate rehealing after the removal of shear forces, making MAX8 an excellent candidate for injectable drug delivery at a localized injury site. The current studies examined the feasibility of using MAX8 as a delivery system for Nerve Growth Factor (NGF) and Brain-derived neurotrophic factor (BDNF), two neurotrophic growth factors currently used in experimental treatments of spinal cord injuries. Experiments determined that encapsulation of NGF and BDNF within MAX8 did not negatively impact gel formation or rehealing and that shear thinning did not result in immediate growth factor release. We found that increased NGF/BDNF dosages increased the amount and rate of growth factor release and that NGF/BDNF release was inversely related to the concentration of MAX8, indicating that growth factor release can be tuned by adjusting MAX8 concentrations. Encapsulation within MAX8 protected NGF and BDNF from in vitro degradation for up to 28 days. Released NGF resulted in the formation of neurite-like extensions in PC12 pheochromocytoma cells, demonstrating that NGF remains biologically active after release from encapsulation. Direct physical contact of PC12 cells with NGF-containing hydrogel did not inhibit neurite-like extension formation. On a molecular level, encapsulated growth factors activated the NGF/BDNF signaling pathways. Taken together, our data show MAX8 acts as a time-release gel, continually releasing low levels of growth factor over 21 days. MAX8 allows for greater dosage control and sustained therapeutic growth factor delivery, potentially alleviating side effects and improving the efficacy of current therapies. PMID:26225909

  14. Luteinizing hormone-releasing hormone (LH-RH) as a diagnostic and research tool in gynecologic endocrinology.

    PubMed

    Taymor, M L; Thompson, I E; Berger, M J; Patton, W

    1974-11-15

    A study is reported on the effects of 150 mcg. of luteinizing hormone-releasing hormone (LH-RH), administered iv to 48 women with 5 types of secondary oligoamenorrhea, on the serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) Levels. At Time 0, patients with pituitary disease showed a markedly diminished LH response and patients with polycystic ovarian disease with enlarged ovaries showed a brisk, elevated LH response. FSH levels in patients with pituitary disease and polycystic ovarian disease showed a negligible rise at Time 0. 9 of 10 patients with pituitary disease and 5 of 9 patients with dietary amenorrhea had a low LH response 30 minutes after LH-RH administration. FSH response 60 minutes after injection in patients with pituitary disease and polycystic ovarian disease seemed to be lowered though too much overlap prevented a complete diagnosis. The conclusion of this initial study is that through baseline determinations of FSH and LH, along with a LH-RH stimulation test, useful data are provided for determining whether amenorrhea is due to ovarian or pituitary failure. A 2nd study evaluated the effects of 150 mcg of LH-RH administered iv before and after the im administration of various dosages of estrogen and progesterone to anovulatory women. A vigorous response in pituitary gonadotropin, particularly LH, was observed with LH-RH administered only. The effect with estrogen and progesterone was diminished pituitary response in terms of LH production. It is concluded that estrogen and progesterone exert a negative feedback effect on gonadotropin secretion at the hypothalamic and pituitary levels.

  15. From Peptides to Proteins: Systematic Control of Net Molecular Charge and Hydrophilicity on the Kinetics of Calcite Growth

    NASA Astrophysics Data System (ADS)

    Elhadj, S.; de Yoreo, J. J.; Hoyer, J. J.; Dove, P. M.

    2006-12-01

    The compartment-specific compositions of biologic molecules isolated from biominerals suggest that control of mineral growth may be linked to biochemical features. Here we define a systematic relationship between the ability of biomolecules in solution to promote the growth of calcite (CaCO3) and their net negative molecular charge and hydrophilicity. The degree of enhancement is dependent on peptide composition, but not on peptide sequence. Data analysis shows that this rate enhancement arises from an increase in the kinetic coefficient. We interpret the mechanism of growth enhancement to be a catalytic process whereby biomolecules reduce the magnitude of the diffusive barrier, Ek, by perturbations that displace water molecules- a water shell destruction mechanism. The result is a decrease in the repulsive barrier for attachment of solutes to the solid phase. This previously unrecognized relationship also rationalizes recently reported data showing acceleration of calcite growth rates over rates measured in the pure system by nanomolar levels of abalone nacre proteins. These findings show that the growth-modifying properties of small model peptides may be scaled up to analyze mineralization processes that are mediated by more complex proteins. We suggest that enhancement of calcite growth may now be estimated a priori from the composition of peptide sequences and the calculated values of hydrophilicity and net molecular charge without need for detailed tests for each biomolecule. This insight may contribute to an improved understanding of mineralization in diverse systems of biomineralization.

  16. Detection and characterization of methionine oxidation in peptides by collision-induced dissociation and electron capture dissociation.

    PubMed

    Guan, Ziqiang; Yates, Nathan A; Bakhtiar, Ray

    2003-06-01

    Electron capture dissociation (ECD) and collision-induced dissociation (CID), the two complementary fragmentation techniques, are demonstrated to be effective in the detection and localization of the methionine sulfoxide [Met(O)] residues in peptides using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. The presence of Met(O) can be easily recognized in the low-energy CID spectrum showing the characteristic loss of methanesulfenic acid (CH(3)SOH, 64 Da) from the side chain of Met(O). The position of Met(O) can then be localized by ECD which is capable of providing extensive peptide backbone fragmentation without detaching the labile Met(O) side chain. We studied CID and ECD of several Met(O)-containing peptides that included the 44-residue human growth hormone-releasing factor (GRF) and the human atrial natriuretic peptide (ANP). The distinction and complementarity of the two fragmentation techniques were particularly remarkable in their effects on ANP, a disulfide bond-containing peptide. While the predominant fragmentation pathway in CID of ANP was the loss of CH(3)SOH (64 Da) from the molecular ion, ECD of ANP resulted in many sequence-informative products, including those from cleavages within the disulfide-bonded cyclic structure, to allow for the direct localization of Met(O) without the typical procedures for disulfide bond reduction followed by [bond]SH alkylation.

  17. Walker 256 Tumor Growth Suppression by Crotoxin Involves Formyl Peptide Receptors and Lipoxin A4

    PubMed Central

    Brigatte, Patrícia; Faiad, Odair Jorge; Ferreira Nocelli, Roberta Cornélio; Landgraf, Richardt G.; Palma, Mario Sergio; Cury, Yara; Curi, Rui; Sampaio, Sandra Coccuzzo

    2016-01-01

    We investigated the effects of Crotoxin (CTX), the main toxin of South American rattlesnake (Crotalus durissus terrificus) venom, on Walker 256 tumor growth, the pain symptoms associated (hyperalgesia and allodynia), and participation of endogenous lipoxin A4. Treatment with CTX (s.c.), daily, for 5 days reduced tumor growth at the 5th day after injection of Walker 256 carcinoma cells into the plantar surface of adult rat hind paw. This observation was associated with inhibition of new blood vessel formation and decrease in blood vessel diameter. The treatment with CTX raised plasma concentrations of lipoxin A4 and its natural analogue 15-epi-LXA4, an effect mediated by formyl peptide receptors (FPRs). In fact, the treatment with Boc-2, an inhibitor of FPRs, abolished the increase in plasma levels of these mediators triggered by CTX. The blockage of these receptors also abolished the inhibitory action of CTX on tumor growth and blood vessel formation and the decrease in blood vessel diameter. Together, the results herein presented demonstrate that CTX increases plasma concentrations of lipoxin A4 and 15-epi-LXA4, which might inhibit both tumor growth and formation of new vessels via FPRs. PMID:27190493

  18. Effects of pig antibacterial peptides on growth performance and intestine mucosal immune of broiler chickens.

    PubMed

    Bao, H; She, R; Liu, T; Zhang, Y; Peng, K S; Luo, D; Yue, Z; Ding, Y; Hu, Y; Liu, W; Zhai, L

    2009-02-01

    Currently, substitutions for antibiotic growth promoters in animals are attracting interest. This study investigated the effects of pig antibacterial peptides (PABP) on growth performance and small intestine mucosal immune responses in broilers. Three hundred 1-d-old Arbor Acre male broiler chickens were randomly allocated to 5 groups with 60 birds per group. The groups were control group; PABP administered in drinking water at 20 and 30 mg/L of water; or PABP supplemented in feed at 150 and 200 mg/kg of diet. The birds were fed a corn-soybean based diet for 6 wk. Chickens were weighed weekly and killed after 42 d of feeding, and growth performance was measured. Samples of the duodenum and jejunum were collected. The villus height, mucosa thickness, alkaline phosphatase activity, and numbers of secreting IgA and goblet cells were evaluated. The PABP-treated groups had greater BW and average daily gain, greater height of villus and thickness of gut mucosa, greater activity of alkaline phosphatase, higher ratio of secreting IgA, and a greater number of goblet cells compared with the control group (P<0.05). In conclusion, PABP can improve the growth performance, increase the intestinal ability to absorb nutrients, and improve the mucosal immunity of the intestine.

  19. PbSe nanocrystal growth as nanocubes and nanorods on peptide nanotubes via different directed-assembly pathways.

    PubMed

    Shi, Menglu; Su, Wei; Matsui, Hiroshi

    2010-11-01

    Pb-binding TAR-1 peptides (Ile-Ser-Leu-Leu-His-Ser-Thr) were covalently conjugated on a bolaamphiphile peptide nanotube substrate and the precursors of PbSe were incubated at room temperature. This resulted in the growth of highly crystalline PbSe nanocubes on this biomimetic cylindrical substrate. The growth mechanism to generate nanocubes occurs via the directed self-assembly of nanoparticles and then nanoparticle fusion. The peptide conformation and the cylindrical peptide nanotube substrate play important roles in the mesoscopic crystallization of PbSe nanocubes. Changing the buffer for the peptide immobilization process from 2-(N-morpholino)ethanesulfonic acid to phosphate induces a transformation in the nanocrystal shape from nanocube to nanorods. The conformational change of the TAR-1 peptide on the nanotubes due to the change in the buffer seems to be responsible for aggregating intermediate nanoparticles in different directions for the directed fusion and mesoscopic crystallization of PbSe into the different shapes.

  20. Cu nanocrystal growth on peptide nanotubes by biomineralization: Size control of Cu nanocrystals by tuning peptide conformation

    NASA Astrophysics Data System (ADS)

    Banerjee, Ipsita A.; Yu, Lingtao; Matsui, Hiroshi

    2003-12-01

    With recent interest in seeking new biologically inspired device-fabrication methods in nanotechnology, a new biological approach was examined to fabricate Cu nanotubes by using sequenced histidine-rich peptide nanotubes as templates. The sequenced histidine-rich peptide molecules were assembled as nanotubes, and the biological recognition of the specific sequence toward Cu lead to efficient Cu coating on the nanotubes. Cu nanocrystals were uniformly coated on the histidine-incorporated nanotubes with high packing density. In addition, the diameter of Cu nanocrystal was controlled between 10 and 30 nm on the nanotube by controlling the conformation of histidine-rich peptide by means of pH changes. Those nanotubes showed significant change in electronic structure by varying the nanocrystal diameter; therefore, this system may be developed to a conductivity-tunable building block for microelectronics and biological sensors. This simple biomineralization method can be applied to fabricate various metallic and semiconductor nanotubes with peptides whose sequences are known to mineralize specific ions.

  1. Peptide-based inhibition of the HOXA9/PBX interaction retards the growth of human meningioma.

    PubMed

    Ando, Hitoshi; Natsume, Atsushi; Senga, Takeshi; Watanabe, Reiko; Ito, Ichiro; Ohno, Masasuke; Iwami, Kenichiro; Ohka, Fumiharu; Motomura, Kazuya; Kinjo, Sayano; Ito, Maki; Saito, Kiyoshi; Morgan, Richard; Wakabayashi, Toshishiko

    2014-01-01

    Meningiomas are the most common type of intracranial tumor, accounting for between 24 and 30 % of primary intracranial tumors. Thus far, no biomarkers exist to reliably predict the clinical outcome of meningiomas. A previous genome-wide methylation analysis revealed that HOXA9 is one of the most functionally relevant biomarkers. In this study, we have examined whether HOXA9 is a potential therapeutic target in meningiomas, using HXR9, a peptide inhibitor of the interaction between HOXA9 and its cofactor PBX. We determined the expression level of HOXA9 in human meningiomas, meningioma cell lines, and normal brain tissue. Meningioma in culture and in subcutaneous tumors was treated with HXR9. We also examined the disruption of HOXA9/PBX dimers. We first confirmed that HOXA9 is highly expressed in meningiomas, but not in normal brain tissue. The HXR9 peptide blocks the binding of HOXA9 to PBX, leading to an alteration of DNA binding, and subsequent regulation of their target genes. HXR9 markedly inhibited the growth of meningioma cells and subcutaneous meningeal tumors. There is no effective chemotherapy for meningiomas at present, and targeting the HOXA9/PBX interaction may represent a novel treatment option for this disease.

  2. Patterning nanofibrils through the templated growth of multiple modified amyloid peptides

    PubMed Central

    Sakai, Hiroki; Watanabe, Ken; Kudoh, Fuki; Kamada, Rui; Chuman, Yoshiro; Sakaguchi, Kazuyasu

    2016-01-01

    There has been considerable interest in the patterning of functionalized nanowires because of the potential applications of these materials to the construction of nanodevices. A variety of biomolecular building blocks containing amyloid peptides have been used to functionalize nanowires. However, the patterning of self-assembled nanowires can be challenging because of the difficulties associated with controlling the self-assembly of these functionalized building blocks. Herein, we present a versatile approach for the patterning of nanowires based on the combination of templated fibril growth with a versatile functionalization method using our structure-controllable amyloid peptides (SCAPs). Using this approach, we have succeeded in the formation of multi-type nanowires with tandem domain structures in high yields. Given that the mixing-SCAP method can lead to the formation of tandem fibrils, it is noteworthy that our method allowed us to control the initiation of fibril formation from the gold nanoparticles, which were attached to a short fibril as initiation points. This approach could be used to prepare a wide variety of fibril patterns, and therefore holds great potential for the development of novel self-assembled nanodevices. PMID:27559011

  3. Peptide-based targeting of the platelet-derived growth factor receptor beta.

    PubMed

    Askoxylakis, Vasileios; Marr, Annabell; Altmann, Annette; Markert, Annette; Mier, Walter; Debus, Jürgen; Huber, Peter E; Haberkorn, Uwe

    2013-04-01

    The aim of this work is to identify new ligands targeting the platelet-derived growth factor receptor beta (PDGFRβ). Biopanning was carried out with a 12-amino-acid phage display library against the recombinant extracellular domain of PDGFRβ. The identified peptide PDGFR-P1 was chemically synthesized and labeled with (125)I or (131)I. In vitro studies were performed on the PDGFRβ-expressing cell lines BxPC3 and MCF7 and on PDGFRβ-transfected HEK cells in comparison to negative control wtHEK293 and CaIX-transfected HEK cells. Biodistribution experiments were performed in Balb/c nude mice, carrying subcutaneously BxPC3 tumors. In vitro studies demonstrated a higher binding to BxPC3, MCF7, and PDGFRβ-tr-HEK cells in comparison to negative control cell lines. Binding was inhibited up to 90% by the unlabeled PDGFR-P1 peptide. Organ distribution studies revealed a higher accumulation in BxPC3 tumors than in most organs. PDGFR-P1 is a promising candidate for targeting human PDGFRβ.

  4. La Crosse virus (LACV) Gc fusion peptide mutants have impaired growth and fusion phenotypes, but remain neurotoxic

    SciTech Connect

    Soldan, Samantha S.; Hollidge, Bradley S.; Wagner, Valentina; Weber, Friedemann; Gonzalez-Scarano, Francisco

    2010-09-01

    La Crosse virus is a leading cause of pediatric encephalitis in the Midwestern United States and an emerging pathogen in the American South. The LACV glycoprotein Gc plays a critical role in entry as the virus attachment protein. A 22 amino acid hydrophobic region within Gc (1066-1087) was recently identified as the LACV fusion peptide. To further define the role of Gc (1066-1087) in virus entry, fusion, and neuropathogenesis, a panel of recombinant LACV (rLACV) fusion peptide mutant viruses was generated. Replication of mutant rLACVs was significantly reduced. In addition, the fusion peptide mutants demonstrated decreased fusion phenotypes relative to LACV-WT. Interestingly, these viruses maintained their ability to cause neuronal loss in culture, suggesting that the fusion peptide of LACV Gc is a determinant of properties associated with neuroinvasion (growth to high titer in muscle cells and a robust fusion phenotype), but not necessarily of neurovirulence.

  5. Effects of guar gum and cellulose on glucose absorption, hormonal release and hepatic metabolism in the pig

    NASA Technical Reports Server (NTRS)

    Nunes, C. S.; Malmlof, K.

    1992-01-01

    Six Large White pigs (mean body-weight 59 (SE 1.7) kg) were surgically fitted with permanent catheters in the portal vein, the brachiocephalic artery and the right hepatic vein, as well as with electromagnetic flow probes around the portal vein and the hepatic artery, and allowed to recover. The non-anaesthetized animals were given a basal non-fibre diet (diet A) alone or together with 60 g guar gum/kg (diet B) or 150 g purified cellulose/kg (diet C) by substitution for mica. The diets were given for weekly periods and according to a replicated 3 x 3 Latin square design. On the last day of each such adaptation period, test meals of 800 g were given before blood sampling. Sampling was continued for 8 h. Guar gum strongly reduced glucose apparent absorption without changing the absorption and the hepatic uptake profiles. Production rates of insulin, gastric inhibitory polypeptide and insulin-like growth factor-1 (IGF-1) were lowest after guar gum ingestion. However, the reductions in peripheral blood insulin levels caused by guar gum were not associated with a change in hepatic insulin extraction. IGF-1 appeared to be strongly secreted by the gut, whereas the liver had a net uptake of the peptide. Ingestion of guar gum increased the hepatic extraction coefficient of gut-produced IGF-1. Guar gum ingestion appeared also to decrease glucagon secretion. Cellulose at the level consumed had very few effects on the variables considered. It is suggested that the modulation of intestinal mechanisms by guar gum was sufficient to mediate the metabolic effects described.

  6. Effects of guar gum and cellulose on glucose absorption, hormonal release and hepatic metabolism in the pig

    NASA Technical Reports Server (NTRS)

    Nunes, C. S.; Malmlof, K.

    1992-01-01

    Six Large White pigs (mean body-weight 59 (SE 1.7) kg) were surgically fitted with permanent catheters in the portal vein, the brachiocephalic artery and the right hepatic vein, as well as with electromagnetic flow probes around the portal vein and the hepatic artery, and allowed to recover. The non-anaesthetized animals were given a basal non-fibre diet (diet A) alone or together with 60 g guar gum/kg (diet B) or 150 g purified cellulose/kg (diet C) by substitution for mica. The diets were given for weekly periods and according to a replicated 3 x 3 Latin square design. On the last day of each such adaptation period, test meals of 800 g were given before blood sampling. Sampling was continued for 8 h. Guar gum strongly reduced glucose apparent absorption without changing the absorption and the hepatic uptake profiles. Production rates of insulin, gastric inhibitory polypeptide and insulin-like growth factor-1 (IGF-1) were lowest after guar gum ingestion. However, the reductions in peripheral blood insulin levels caused by guar gum were not associated with a change in hepatic insulin extraction. IGF-1 appeared to be strongly secreted by the gut, whereas the liver had a net uptake of the peptide. Ingestion of guar gum increased the hepatic extraction coefficient of gut-produced IGF-1. Guar gum ingestion appeared also to decrease glucagon secretion. Cellulose at the level consumed had very few effects on the variables considered. It is suggested that the modulation of intestinal mechanisms by guar gum was sufficient to mediate the metabolic effects described.

  7. Regulation of growth-blocking peptide expression during embryogenesis of the cabbage armyworm.

    PubMed

    Tsuzuki, Seiji; Sekiguchi, Shiroh; Hayakawa, Yoichi

    2005-10-07

    Growth-blocking peptide (GBP) is an insect cytokine with diverse biological functions. Northern blot analysis revealed high heterogeneity in the size distribution of GBP mRNAs as well as in the tissues where they are detected. The spatio-temporal transcription pattern is dynamic, especially during embryogenesis. Gel shift assays demonstrated that the cabbage armyworm embryo nuclear extract specifically binds to a 178-bp element, at position +234 to +411 from the transcription start site of the 1.3 kb GBP transcript, in which two Drosophila Deformed (Dfd) binding sites are repeated in tandem. The specific binding between this element and Dfd was demonstrated using recombinant cabbage armyworm Dfd protein. Silencing the Dfd expression in embryos by treating with Dfd double-stranded RNA did not reduce the expression level of GBP, but ectopic GBP expression was observed in the lateral region of the embryo, suggesting that Dfd could serve as a transcriptional repressor for the GBP gene.

  8. Bioactive hydrogels made from step-growth derived PEG-peptide macromers.

    PubMed

    Miller, Jordan S; Shen, Colette J; Legant, Wesley R; Baranski, Jan D; Blakely, Brandon L; Chen, Christopher S

    2010-05-01

    Synthetic hydrogels based on poly(ethylene glycol) (PEG) have been used as biomaterials for cell biology and tissue engineering investigations. Bioactive PEG-based gels have largely relied on heterobifunctional or multi-arm PEG precursors that can be difficult to synthesize and characterize or expensive to obtain. Here, we report an alternative strategy, which instead uses inexpensive and readily available PEG precursors to simplify reactant sourcing. This new approach provides a robust system in which to probe cellular interactions with the microenvironment. We used the step-growth polymerization of PEG diacrylate (PEGDA, 3400Da) with bis-cysteine matrix metalloproteinase (MMP)-sensitive peptides via Michael-type addition to form biodegradable photoactive macromers of the form acrylate-PEG-(peptide-PEG)(m)-acrylate. The molecular weight (MW) of these macromers is controlled by the stoichiometry of the reaction, with a high proportion of resultant macromer species greater than 500kDa. In addition, the polydispersity of these materials was nearly identical for three different MMP-sensitive peptide sequences subjected to the same reaction conditions. When photopolymerized into hydrogels, these high MW materials exhibit increased swelling and sensitivity to collagenase-mediated degradation as compared to previously published PEG hydrogel systems. Cell-adhesive acrylate-PEG-CGRGDS was synthesized similarly and its immobilization and stability in solid hydrogels was characterized with a modified Lowry assay. To illustrate the functional utility of this approach in a biological setting, we applied this system to develop materials that promote angiogenesis in an ex vivo aortic arch explant assay. We demonstrate the formation and invasion of new sprouts mediated by endothelial cells into the hydrogels from embedded embryonic chick aortic arches. Furthermore, we show that this capillary sprouting and three-dimensional migration of endothelial cells can be tuned by

  9. Preparation and properties of nanometer silk fibroin peptide/polyvinyl alcohol blend films for cell growth.

    PubMed

    Luo, Qin; Chen, Zhongmin; Hao, Xuefei; Zhu, Qiangsong; Zhou, Yucheng

    2013-10-01

    Nanometer silk fibroin peptide (Nano-SFP) was prepared from silkworm cocoons through the process of dissolution, dialysis and enzymolysis. For comparison, silk fibroin was decomposed with α-chymotrypsin, trypsin and neutrase, respectively. From the SEM and particle size analysis results, the Nano-SFP prepared by neutrase was found to be the most desirable at about 50-200 nm. Nano-SFP/polyvinyl alcohol films (Nano-SFP/PVA) were prepared by blending Nano-SFP and PVA in water with different weight ratios of 10/90, 20/80, 30/70, and 40/60. The films were characterized by IR, SEM, TG, DSC and tensile strength test for investigating their structure, surface morphology, thermostability, and mechanical property. The results showed that Nano-SFP inserted in the PVA films with small linear particles, and Nano-SFP/PVA films exhibited smooth surface, good thermostability and tensile strength. The growth of Chinese hamster ovary (CHO) cells on films with and without Nano-SFP was investigated with MTT colorimetric assay to assess the films' ability to promote cell growth. It was observed that the Nano-SFP improved cell adhesion on the film surface, and the ability of promoting cell growth increased with the increasing content of Nano-SFP in the blend films. Nano-SFP/PVA film with the ratio of 30/70 was concluded to have the best properties.

  10. Peptide YY Levels across Pubertal Stages and Associations with Growth Hormone

    PubMed Central

    Lloyd, Benjamin; Ravi, Praful; Mendes, Nara; Klibanski, Anne; Misra, Madhusmita

    2010-01-01

    Context: Changes in appetite-regulating peptides may impact food intake during puberty and facilitate the pubertal growth spurt. Peptide YY (PYY) is an anorexigenic hormone that is high in anorexia nervosa and low in obesity, inhibits GnRH secretion, and is suppressed by GH administration. The relationship between PYY and GH has not been examined across puberty. Objectives: We hypothesized that PYY would be inversely associated with GH in adolescents and would be lowest when GH is highest. Design and Setting: We conducted a cross-sectional study at a Clinical Research Center. Subjects: We studied 87 children, 46 boys and 41 girls ages 9–17 yr at Tanner stages 1–5 of puberty (10th–90th percentiles for body mass index). Outcome Measures: We measured fasting PYY and nadir GH levels after administration of an oral glucose load. Leptin levels were also measured. Results: Fasting PYY was lowest and nadir GH highest in boys in Tanner stages 3–4 (P = 0.02) and in girls in Tanner stages 2–3 (P = 0.02). Leptin levels were highest in early pubertal boys and late pubertal girls. For the group as a whole and within genders, even after controlling for body mass index, log nadir GH correlated inversely with log PYY (P = 0.003, 0.07, and 0.02). PYY levels did not correlate with leptin levels. Conclusions: During mid-puberty, at a time when GH levels are the highest, PYY is at a nadir, and these low PYY levels may facilitate pubertal progression and growth. PMID:20375207

  11. Simultaneous inhibition of key growth pathways in melanoma cells and tumor regression by a designed bidentate constrained helical peptide.

    PubMed

    Dhar, Amlanjyoti; Mallick, Shampa; Ghosh, Piya; Maiti, Atanu; Ahmed, Israr; Bhattacharya, Seemana; Mandal, Tapashi; Manna, Asit; Roy, Koushik; Singh, Sandeep; Nayak, Dipak Kumar; Wilder, Paul T; Markowitz, Joseph; Weber, David; Ghosh, Mrinal K; Chattopadhyay, Samit; Guha, Rajdeep; Konar, Aditya; Bandyopadhyay, Santu; Roy, Siddhartha

    2014-07-01

    Protein-protein interactions are part of a large number of signaling networks and potential targets for drug development. However, discovering molecules that can specifically inhibit such interactions is a major challenge. S100B, a calcium-regulated protein, plays a crucial role in the proliferation of melanoma cells through protein-protein interactions. In this article, we report the design and development of a bidentate conformationally constrained peptide against dimeric S100B based on a natural tight-binding peptide, TRTK-12. The helical conformation of the peptide was constrained by the substitution of α-amino isobutyric acid--an amino acid having high helical propensity--in positions which do not interact with S100B. A branched bidentate version of the peptide was bound to S100B tightly with a dissociation constant of 8 nM. When conjugated to a cell-penetrating peptide, it caused growth inhibition and rapid apoptosis in melanoma cells. The molecule exerts antiproliferative action through simultaneous inhibition of key growth pathways, including reactivation of wild-type p53 and inhibition of Akt and STAT3 phosphorylation. The apoptosis induced by the bidentate constrained helix is caused by direct migration of p53 to mitochondria. At moderate intravenous dose, the peptide completely inhibits melanoma growth in a mouse model without any significant observable toxicity. The specificity was shown by lack of ability of a double mutant peptide to cause tumor regression at the same dose level. The methodology described here for direct protein-protein interaction inhibition may be effective for rapid development of inhibitors against relatively weak protein-protein interactions for de novo drug development.

  12. Preparation and characterization of luteinising-hormone releasing hormone nanoliposomal microbubbles specifically targeting ovarian cancer cells in vitro.

    PubMed

    Zhang, Jinyi; Liu, Sisun; Zhu, Yuanfang; Zhang, Liping; Li, Wenjuan; Wang, Fen; Huang, Shuying

    2014-07-01

    The aim of the present study was to prepare luteinizing-hormone releasing hormone (LHRH) nanoliposomal microbubbles specifically targeting ovarian cancer cells. The lyophilization/sonication method was used to prepare non-targeting nanoliposomal microbubbles (N-N-Mbs). Using the biotin-avidin bridge method, conjugated LHRH antibodies to N-N-Mbs generated LHRH nanoliposomal microbubbles (LHRH-N-Mbs) specifically targeting ovarian cancer cells. The morphology and physicochemical properties of the microbubbles was detected using an optical microscope and zeta detector. The binding affinity between the secondary antibody and LHRH-N-Mbs or N-N-Mbs was determined by flow cytometry. The binding of LHRH-N-Mb to human ovarian cancer cells (OVCAR-3) was detected by light microscopy. The rounded and uniformly distributed N-N-Mbs and LHRH-N-Mbs were successfully generated. The particle size ranged from 295-468 nm with a mean of 360 nm for N-N-Mbs or 369-618 nm with a mean of 508 nm for LHRH-N-Mbs. There was a significant difference in size between the two groups (P<0.05), although the surface potential of the two microbubbles remained the same (-14.6 mV). Following being kept at room temperature for 14 days, no significant difference in the physicochemical properties of the LHRH-N-Mbs was detected compared with that of freshly prepared microbubbles. The secondary antibody binding rate of LHRH-N-Mbs and N-N-Mbs was 75.6 and 0.83%, respectively. Furthermore, the formation of a rosette-like structure surrounding OVCAR-3 cells was observed after the cells were incubated with LHRH-N-Mbs, whereas pre-incubation with LHRH antibody blocked this rosette formation. In conclusion, LHRH-N-Mbs specifically targeting ovarian cancer cells were successfully prepared through biotin-avidin mediation and the lyophilization/sonication method. The key feature of LHRH-N-Mbs is their small size, stability and high efficiency in targeting human OVCAR-3 cells in vitro.

  13. Influences of castration and testosterone on spring to summer changes in release of luteinizing-hormone-releasing hormone in rabbits.

    PubMed

    Lin, W W; Ramirez, V D

    1992-09-01

    Push-pull cannulae were implanted toward the tuberal region of the hypothalamus in ten intact New Zealand male rabbits. In the first experiment, rabbits were perfused at different times after castration: 5-10 days (n = 10), 22-31 days (n = 9) and 50-64 days (n = 8). The release, mean amplitude and mean frequency of luteinizing-hormone-releasing hormone (LHRH) signals from 37 perfusions in ten animals were analysed in intact rabbits and at different times after castration. No significant changes in release of LHRH and in amplitude were observed, but the frequency was significantly higher 22-31 days after castration than in intact rabbits (intact: 0.86 +/- 0.12; castrated: 1.20 +/- 0.13 pulses h-1, P < 0.035; n = 9). In Expt 2, testosterone and placebo Silastic capsules were implanted in the castrated rabbits. Perfusions were performed in the following four periods, defined by season and time after testosterone and placebo implants: (i) spring; before implants, (ii) late spring; 0-2 weeks after implants, (iii) summer solstice; 2-4 weeks after implants and (iv) summer; 4-6 weeks after implants. Castrated rabbits were perfused during spring; castrated rabbits with testosterone capsule implants were perfused during late spring, around summer solstice and in summer and castrated rabbits with placebo implants were perfused during periods (iii) and (iv). Castrated animals with placebo implants showed no significant changes in mean LHRH release and amplitude, although the frequency was significantly higher around the summer solstice period than in castrated rabbits perfused in the spring. In castrated rabbits with testosterone implants LHRH release was significantly higher in late spring than around the summer solstice and in the summer. In addition, the concentrations of LHRH in late spring were significantly higher than those of intact and castrated animals. In contrast, mean LHRH amplitude and frequency did not change. Mean amount of LHRH released and amplitude in

  14. The glucagon-like peptide 2 pathway may mediate growth and development of the bovine gastrointestinal tract

    USDA-ARS?s Scientific Manuscript database

    Glucagon-like peptide 2 (GLP-2), secreted by enteroendocrine cells, has a number of physiological effects on the intestine of monogastric species, including promotion of growth of intestinal epithelium, reduction of epithelial cell apoptosis, and enhancement of intestinal blood flow, nutrient absorp...

  15. Combination of a long-acting delivery system for luteinizing hormone-releasing hormone agonist with Novantrone chemotherapy: increased efficacy in the rat prostate cancer model.

    PubMed Central

    Schally, A V; Kook, A I; Monje, E; Redding, T W; Paz-Bouza, J I

    1986-01-01

    The combination of hormonal treatment based on a long-acting delivery system for the agonist [6-D-tryptophan]luteinizing hormone-releasing hormone ([D-Trp6]-LH-RH) with the chemotherapeutic agent Novantrone (mitoxantrone dihydrochloride) was studied in the Dunning R3327H rat prostate cancer model. Microcapsules of [D-Trp6]-LH-RH formulated from poly(DL-lactide-co-glycolide) and calculated to release a controlled dose of 25 micrograms/day were injected intramuscularly once a month. Novantrone (0.25 mg/kg) was injected intravenously once every 3 weeks. Three separate experiments were carried out. When the therapy was started 45 days after transplantation and continued for 70 days, tumor volume in the presence of the microcapsules (966 +/- 219 mm3) or Novantrone (3606 +/- 785 mm3) given alone was significantly decreased compared to controls (14,476 +/- 3045 mm3). However, the combination of microcapsules and Novantrone caused a greater inhibition of tumor growth (189 +/- 31 mm3) than the single agents. Similar effects were seen when the percent increase in tumor volume was examined. Tumor volume increased 10,527 +/- 1803% for the control group. The inhibition of growth caused by the [D-Trp6]LH-RH microcapsules alone (672 +/- 153% increase in volume) was again greater than that caused by Novantrone alone (2722 +/- 421% increase). The combination of the two agents was again the most effective, resulting in an increase in tumor volume of only 105 +/- 29%. Control tumors weighed 30.0 +/- 6.5 g. Tumor weights were much less in the groups treated with either microcapsules (3.28 +/- 0.69 g) or Novantrone (19.53 +/- 3.3 g) alone. The lowest tumor weights after 70 days of treatment were obtained in the group that received the combination of [D-Trp6]LH-RH microcapsules and Novantrone (1.02 +/- 0.2 g). Testes and ventral prostate weights were significantly diminished by the administration of microcapsules of [D-Trp6]LH-RH alone or in combination with Novantrone. In both of these

  16. Gastrin-releasing peptide receptor (GRPr) promotes EMT, growth, and invasion in canine prostate cancer.

    PubMed

    Elshafae, Said M; Hassan, Bardes B; Supsavhad, Wachiraphan; Dirksen, Wessel P; Camiener, Rachael Y; Ding, Haiming; Tweedle, Michael F; Rosol, Thomas J

    2016-06-01

    The gastrin-releasing peptide receptor (GRPr) is upregulated in early and late-stage human prostate cancer (PCa) and other solid tumors of the mammary gland, lung, head and neck, colon, uterus, ovary, and kidney. However, little is known about its role in prostate cancer. This study examined the effects of a heterologous GRPr agonist, bombesin (BBN), on growth, motility, morphology, gene expression, and tumor phenotype of an osteoblastic canine prostate cancer cell line (Ace-1) in vitro and in vivo. The Ace-1 cells were stably transfected with the human GRPr and tumor cells were grown in vitro and as subcutaneous and intratibial tumors in nude mice. The effect of BBN was measured on cell proliferation, cell migration, tumor growth (using bioluminescence), tumor cell morphology, bone tumor phenotype, and epithelial-mesenchymal transition (EMT) and metastasis gene expression (quantitative RT-PCR). GRPr mRNA expression was measured in primary canine prostate cancers and normal prostate glands. Bombesin (BBN) increased tumor cell proliferation and migration in vitro and tumor growth and invasion in vivo. BBN upregulated epithelial-to-mesenchymal transition (EMT) markers (TWIST, SNAIL, and SLUG mRNA) and downregulated epithelial markers (E-cadherin and β-catenin mRNA), and modified tumor cell morphology to a spindle cell phenotype. Blockade of GRPr upregulated E-cadherin and downregulated VIMENTIN and SNAIL mRNA. BBN altered the in vivo tumor phenotype in bone from an osteoblastic to osteolytic phenotype. Primary canine prostate cancers had increased GRPr mRNA expression compared to normal prostates. These data demonstrated that the GRPr is important in prostate cancer growth and progression and targeting GRPr may be a promising strategy for treatment of prostate cancer. Prostate 76:796-809, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Efficient inhibition of tumor angiogenesis and growth by a synthetic peptide blocking S100A4-methionine aminopeptidase 2 interaction

    PubMed Central

    Ochiya, Takahiro; Takenaga, Keizo; Asagiri, Masataka; Nakano, Kazumi; Satoh, Hitoshi; Watanabe, Toshiki; Imajoh-Ohmi, Shinobu; Endo, Hideya

    2015-01-01

    The prometastatic calcium-binding protein, S100A4, is expressed in endothelial cells, and its downregulation markedly suppresses tumor angiogenesis in a xenograft cancer model. Given that endothelial S100A4 can be a molecular target for inhibiting tumor angiogenesis, we addressed here whether synthetic peptide capable of blocking S100A4-effector protein interaction could be a novel antiangiogenic agent. To examine this hypothesis, we focused on the S100A4-binding domain of methionine aminopeptidase 2, an effector protein, which plays a role in endothelial cell growth. Overexpression of the domain in mouse endothelial MSS31 cells reduced DNA synthesis, and the corresponding synthetic peptide (named NBD) indeed interacted with S100A4 and inhibited capillary formation in vitro and new blood vessel formation in vivo. Intriguingly, a single intra-tumor administration of the NBD peptide in human prostate cancer xenografts significantly reduced vascularity, resulting in tumor regression. Mechanistically, the NBD peptide enhanced assembly of nonmuscle myosin IIA filaments along with Ser1943 phosphorylation, stimulated formation of focal adhesions without phosphorylation of focal adhesion kinase, and provoked G1/S arrest of the cell cycle. Altogether, the NBD peptide is a potent inhibitor for tumor angiogenesis, and is the first example of an anticancer peptide drug developed on the basis of an endothelial S100A4-targeted strategy. PMID:26029719

  18. A peptide targeted against phosphoprotein and leader RNA interaction inhibits growth of Chandipura virus -- an emerging rhabdovirus.

    PubMed

    Roy, Arunava; Chakraborty, Prasenjit; Polley, Smarajit; Chattopadhyay, Dhrubajyoti; Roy, Siddhartha

    2013-11-01

    The fatal illness caused by Chandipura virus (CHPV), an emerging pathogen, presently lacks any therapeutic option. Previous research suggested that interaction between the virally encoded phosphoprotein (P) and the positive sense leader RNA (le-RNA) may play an important role in the viral lifecycle. In this report, we have identified a β-sheet/loop motif in the C-terminal domain of the CHPV P protein as essential for this interaction. A synthetic peptide encompassing this motif and spanning a continuous stretch of 36 amino acids (Pep208-243) was found to bind the le-RNA in vitro and inhibit CHPV growth in infected cells. Furthermore, a stretch of three amino acid residues at position 217-219 was identified as essential for this interaction, both in vitro and in infected cells. siRNA knockdown-rescue experiments demonstrated that these three amino acid residues are crucial for the leader RNA binding function of P protein in the CHPV life cycle. Mutations of these three amino acid residues render the peptide completely ineffective against CHPV. Effect of inhibition of phosphoprotein-leader RNA interaction on viral replication was assayed. Peptide Pep208-243 tagged with a cell penetrating peptide was found to inhibit CHPV replication as ascertained by real time RT-PCR. The specific inhibition of viral growth observed using this peptide suggests a new possibility for designing of anti-viral agents against Mononegavirale group of human viruses.

  19. Shape changes induced by biologically active peptides and nerve growth factor in blood platelets of rabbits.

    PubMed

    Gudat, F; Laubscher, A; Otten, U; Pletscher, A

    1981-11-01

    1 Nerve growth factor (NGF), substance P (SP) and thymopoietin all caused shape change reactions of rapid onset in rabbit platelets. NGF had the highest maximal effect, and SP the lowest EC50 (concentration causing half maximal shape change). The action of SP was reversible within 5 min, whereas that of NGF lasted for at least 1 h. A series of other peptides were inactive. 2 After preincubation of platelets with SP, a second application of SP no longer caused a shape change reaction, whereas the effect of NGF was not influenced. 3 An oxidized NGF-derivative without biological activity did not cause a shape change reaction, neither did epidermal growth factor. 4 Prostaglandin E1 (PGE1) and pretreatment of the platelets with 3% butanol, which counteract the shape changes caused by 5-hydroxytryptamine (5-HT) and adenosine 3',5'-diphosphate, also antagonized those induced by NGF and SP. Neither heparin nor methysergide, an antagonist of 5-HT-receptors, influenced the shape change induced by NGF or SP. The action of NGF was also antagonized by a specific antibody to NGF. 5 Thymopoietin, like the basic polypeptide polyornithine (mol. wt. 40,000) was not antagonized by PGE1 and butanol. Heparin, which counteracted the effect of polyornithine, did not influence that of thymopoietin. 6 In conclusion, different modes of action are involved in the shape change of blood platelets induced by polypeptides and proteins. SP and NGF may act by stimulating specific membrane receptors.

  20. High sensitivity mass spectrometric quantification of serum growth hormone by amphiphilic peptide conjugation

    NASA Astrophysics Data System (ADS)

    Arsene, Cristian G.; Schulze, Dirk; Kratzsch, Jürgen; Henrion, André

    2012-12-01

    Amphiphilic peptide conjugation affords a significant increase in sensitivity with protein quantification by electrospray-ionization mass spectrometry. This has been demonstrated here for human growth hormone in serum using N-(3-iodopropyl)-N,N,N-dimethyloctylammonium iodide (IPDOA-iodide) as derivatizing reagent. The signal enhancement achieved in comparison to the method without derivatization enables extension of the applicable concentration range down to the very low concentrations as encountered with clinical glucose suppression tests for patients with acromegaly. The method has been validated using a set of serum samples spiked with known amounts of recombinant 22 kDa growth hormone in the range of 0.48 to 7.65 \\mug/L. The coefficient of variation (CV) calculated, based on the deviation of results from the expected concentrations, was 3.5% and the limit of quantification (LoQ) was determined as 0.4 \\mug/L. The potential of the method as a tool in clinical practice has been demonstrated with patient samples of about 1 \\mug/L.

  1. Actions of cocaine- and amphetamine-regulated transcript (CART) peptide on regulation of appetite and hypothalamo-pituitary axes in vitro and in vivo in male rats.

    PubMed

    Stanley, S A; Small, C J; Murphy, K G; Rayes, E; Abbott, C R; Seal, L J; Morgan, D G; Sunter, D; Dakin, C L; Kim, M S; Hunter, R; Kuhar, M; Ghatei, M A; Bloom, S R

    2001-03-02

    Cocaine- and amphetamine-regulated transcript (CART) and CART peptide are abundant in hypothalamic nuclei controlling anterior pituitary function. Intracerebroventricular (ICV) injection of CART peptide results in neuronal activation in the paraventricular nucleus (PVN), rich in corticotrophin-releasing factor (CRH) and thyrotrophin-releasing factor (TRH) immunoreactive neurons. The aims of this study were three-fold. Firstly, to examine the effects of CART peptide on hypothalamic releasing factors in vitro, secondly, to examine the effect of ICV injection of CART peptide on plasma pituitary hormones and finally to examine the effect of PVN injection of CART peptide on food intake and circulating pituitary hormones. CART(55-102) (100 nM) peptide significantly stimulated the release of CRH, TRH and neuropeptide Y from hypothalamic explants but significantly reduced alpha melanocyte stimulating hormone release in vitro. Following ICV injection of 0.2 nmol CART(55-102), a dose which significantly reduces food intake, plasma prolactin (PRL), growth hormone (GH) and adrenocorticotrophin hormone (ACTH) and corticosterone increased significantly. Following PVN injection of CART(55-102), food intake was significantly reduced only at 0.2 and 0.6 nmol. However, PVN injection of 0.02 nmol CART(55-102) produced a significant increase in plasma ACTH. ICV injection of CART peptide significantly reduces food intake. Unlike many anorexigenic peptides, there is no increased sensitivity to PVN injection of CART(55-102). In contrast, both ICV and PVN injection of CART(55-102) significantly increased plasma ACTH and release of hypothalamic CRH is significantly increased by CART peptide in vitro. This suggests that CART peptide may play a role in the control of pituitary function and in particular the hypothalamo-pituitary adrenal axis.

  2. Solution Structures, Dynamics, and Ice Growth Inhibitory Activity of Peptide Fragments Derived from an Antarctic Yeast Protein

    PubMed Central

    Asmawi, Azren A.; Rahman, Mohd Basyaruddin A.; Murad, Abdul Munir A.; Mahadi, Nor M.; Basri, Mahiran; Rahman, Raja Noor Zaliha A.; Salleh, Abu B.; Chatterjee, Subhrangsu; Tejo, Bimo A.; Bhunia, Anirban

    2012-01-01

    Exotic functions of antifreeze proteins (AFP) and antifreeze glycopeptides (AFGP) have recently been attracted with much interest to develop them as commercial products. AFPs and AFGPs inhibit ice crystal growth by lowering the water freezing point without changing the water melting point. Our group isolated the Antarctic yeast Glaciozyma antarctica that expresses antifreeze protein to assist it in its survival mechanism at sub-zero temperatures. The protein is unique and novel, indicated by its low sequence homology compared to those of other AFPs. We explore the structure-function relationship of G. antarctica AFP using various approaches ranging from protein structure prediction, peptide design and antifreeze activity assays, nuclear magnetic resonance (NMR) studies and molecular dynamics simulation. The predicted secondary structure of G. antarctica AFP shows several α-helices, assumed to be responsible for its antifreeze activity. We designed several peptide fragments derived from the amino acid sequences of α-helical regions of the parent AFP and they also showed substantial antifreeze activities, below that of the original AFP. The relationship between peptide structure and activity was explored by NMR spectroscopy and molecular dynamics simulation. NMR results show that the antifreeze activity of the peptides correlates with their helicity and geometrical straightforwardness. Furthermore, molecular dynamics simulation also suggests that the activity of the designed peptides can be explained in terms of the structural rigidity/flexibility, i.e., the most active peptide demonstrates higher structural stability, lower flexibility than that of the other peptides with lower activities, and of lower rigidity. This report represents the first detailed report of downsizing a yeast AFP into its peptide fragments with measurable antifreeze activities. PMID:23209600

  3. Efficacy of Continuously Administered PEDF-Derived Synthetic Peptides against Osteosarcoma Growth and Metastasis

    PubMed Central

    Broadhead, Matthew L.; Choong, Peter F. M.; Dass, Crispin R.

    2012-01-01

    The potent antiangiogenic pigment epithelium-derived factor (PEDF) has shown promise against osteosarcoma, a tumour that originates in the bone and metastasises to the lungs. Neurotrophic, antiangiogenic, antiproliferative, and antimetastatic properties of PEDF have been attributed to a number of functional epitopes on the PEDF glycoprotein. StVOrth-2 (residues 78–102) and StVOrth-3 (residues 90–114) are two PEDF-derived peptides based on these functional epitopes. StVOrth-2 has previously been shown to inhibit osteosarcoma cell proliferation, while StVOrth-3 increased osteosarcoma cell adhesion to collagen I in vitro. In this paper, we have evaluated systemically and continuously delivered StVOrth-2 and StVOrth-3 using a clinically relevant murine model of osteosarcoma with spontaneous metastasis. Treatment with StVOrth-2 or StVOrth-3 with microosmotic pumps was initiated after primary osteosarcoma was established in the tibia. While treatment with StVOrth-2 and StVOrth-3 did not appear to affect local tumour invasion, tumour necrosis or apoptosis, StVOrth-2 predominantly restricted the growth of primary tumours, while StVOrth-3 restricted the burden of pulmonary metastatic disease. No peptide caused gross toxicity in mouse tissues as assessed by measuring weight of animals, serum biochemistry, and gross tissue observation. The differential effects exhibited by StVOrth-2 and StVOrth-3 in this orthotopic model of osteosarcoma may be related to the functional epitopes on the PEDF glycoprotein that they represent. PMID:22701300

  4. Growth phase and pH influence peptide signaling for competence development in Streptococcus mutans.

    PubMed

    Guo, Qiang; Ahn, Sang-Joon; Kaspar, Justin; Zhou, Xuedong; Burne, Robert A

    2014-01-01

    The development of competence by the dental caries pathogen Streptococcus mutans is mediated primarily through the alternative sigma factor ComX (SigX), which is under the control of multiple regulatory systems and activates the expression of genes involved in DNA uptake and recombination. Here we report that the induction of competence and competence gene expression by XIP (sigX-inducing peptide) and CSP (competence-stimulating peptide) is dependent on the growth phase and that environmental pH has a potent effect on the responses to XIP. A dramatic decline in comX and comS expression was observed in mid- and late-exponential-phase cells. XIP-mediated competence development and responses to XIP were optimal around a neutral pH, although mid-exponential-phase cells remained refractory to XIP treatment, and acidified late-exponential-phase cultures were resistant to killing by high concentrations of XIP. Changes in the expression of the genes for the oligopeptide permease (opp), which appears to be responsible for the internalization of XIP, could not entirely account for the behaviors observed. Interestingly, comS and comX expression was highly induced in response to endogenously overproduced XIP or ComS in mid-exponential-phase cells. In contrast to the effects of pH on XIP, competence induction and responses to CSP in complex medium were not affected by pH, although a decreased response to CSP in cells that had exited early-exponential phase was observed. Collectively, these results indicate that competence development may be highly sensitive to microenvironments within oral biofilms and that XIP and CSP signaling in biofilms could be spatially and temporally heterogeneous.

  5. Levels of hormones and cytokines associated with growth in Honamlı and native hair goats.

    PubMed

    Devrim, A K; Elmaz, O; Mamak, N; Sudagidan, M

    2015-01-01

    This study was designed to assess alterations of hormone and cytokine levels associated with growth period during puberty in Honamlı goats which were identified as a new goat breed and had one of the highest meat production potential among the other goat breeds in Turkey. Honamlı goats are originated from native hair goats, so parallel studies of sampling and analyzing were conducted also in native hair goats which have moderate meat production. Blood serum samples of Honamlı (n=90) and native hair goats (n=90) were obtained from the pure herds in Korkuteli and Ka districts of Anatolia. Concentrations of growth hormone (GH), myostatin (MSTN), insulin-like growth factor (IGF), growth hormone releasing hormone (GHRH), growth hormone releasing peptide (GHRP), leptin, transforming growth factor-betal (TGF-β1) and vascular endothelial cell growth factor (VEGF) levels were measured by ELISA in each breed in the age groups of 4, 8 and 12 months. The present results indicate interesting correlations among the age groups and all the examined hormone and cytokine parameters exhibited significant (P<0.05 and P<0.001) differences. The parameters investigated were usually begun to increase after 4 months of age in the both breeds and sexes. Therefore, this paper supported the view that the beginning of hormonal alterations of goats could occur at 4th month of age. The results reported here emphasize the primary role played by GH, MSTN, IGF-1, leptin, GHRH, GHRP, TGF-βi and VEGF in the first year growth period of goats.

  6. Enterococcus faecalis strains from food, environmental, and clinical origin produce ACE-inhibitory peptides and other bioactive peptides during growth in bovine skim milk.

    PubMed

    Gútiez, Loreto; Gómez-Sala, Beatriz; Recio, Isidra; del Campo, Rosa; Cintas, Luis M; Herranz, Carmen; Hernández, Pablo E

    2013-08-16

    Enterococcus faecalis isolates from food and environmental origin were evaluated for their angiotensin-converting enzyme (ACE)-inhibitory activity (ACE-IA) after growth in bovine skim milk (BSM). Most (90% active) but not all (10% inactive) E. faecalis strains produced BSM-derived hydrolysates with high ACE-IA. Known ACE-inhibitory peptides (ACE-IP) and an antioxidant peptide were identified in the E. faecalis hydrolysates by reversed-phase high-performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS). Antimicrobial activity against Pediococcus damnosus CECT4797 and Listeria ivanovii CECT913 was also observed in the E. faecalis hydrolysates. The incidence of virulence factors in the E. faecalis strains with ACE-IA and producers of ACE-IP was variable but less virulence factors were observed in the food and environmental strains than in the clinical reference strains. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) based analysis demonstrated that food and environmental E. faecalis strains were genetically different from those of clinical origin. When evaluated, most E. faecalis strains of clinical origin also originated BSM-derived hydrolysates with high ACE-IA due to the production of ACE-IP. Accordingly, the results of this work suggest that most E. faecalis strains of food, environmental and clinical origin produce BSM-derived bioactive peptides with human health connotations and potential biotechnological applications. © 2013 Elsevier B.V. All rights reserved.

  7. Imaging exocytosis of single glucagon-like peptide-1 containing granules in a murine enteroendocrine cell line with total internal reflection fluorescent microscopy

    SciTech Connect

    Ohara-Imaizumi, Mica; Aoyagi, Kyota; Akimoto, Yoshihiro; Nakamichi, Yoko; Nishiwaki, Chiyono; Kawakami, Hayato; Nagamatsu, Shinya

    2009-12-04

    To analyze the exocytosis of glucagon-like peptide-1 (GLP-1) granules, we imaged the motion of GLP-1 granules labeled with enhanced yellow fluorescent protein (Venus) fused to human growth hormone (hGH-Venus) in an enteroendocrine cell line, STC-1 cells, by total internal reflection fluorescent (TIRF) microscopy. We found glucose stimulation caused biphasic GLP-1 granule exocytosis: during the first phase, fusion events occurred from two types of granules (previously docked granules and newcomers), and thereafter continuous fusion was observed mostly from newcomers during the second phase. Closely similar to the insulin granule fusion from pancreatic {beta} cells, the regulated biphasic exocytosis from two types of granules may be a common mechanism in glucose-evoked hormone release from endocrine cells.

  8. The synthetic peptide P111-136 derived from the C-terminal domain of heparin affin regulatory peptide inhibits tumour growth of prostate cancer PC-3 cells

    PubMed Central

    2011-01-01

    Background Heparin affin regulatory peptide (HARP), also called pleiotrophin, is a heparin-binding, secreted factor that is overexpressed in several tumours and associated to tumour growth, angiogenesis and metastasis. The C-terminus part of HARP composed of amino acids 111 to 136 is particularly involved in its biological activities and we previously established that a synthetic peptide composed of the same amino acids (P111-136) was capable of inhibiting the biological activities of HARP. Here we evaluate the ability of P111-136 to inhibit in vitro and in vivo the growth of a human tumour cell line PC-3 which possess an HARP autocrine loop. Methods A total lysate of PC-3 cells was incubated with biotinylated P111-136 and pulled down for the presence of the HARP receptors in Western blot. In vitro, the P111-136 effect on HARP autocrine loop in PC-3 cells was determined by colony formation in soft agar. In vivo, PC-3 cells were inoculated in the flank of athymic nude mice. Animals were treated with P111-136 (5 mg/kg/day) for 25 days. Tumour volume was evaluated during the treatment. After the animal sacrifice, the tumour apoptosis and associated angiogenesis were evaluated by immunohistochemistry. In vivo anti-angiogenic effect was confirmed using a mouse Matrigel™ plug assay. Results Using pull down experiments, we identified the HARP receptors RPTPβ/ζ, ALK and nucleolin as P111-136 binding proteins. In vitro, P111-136 inhibits dose-dependently PC-3 cell colony formation. Treatment with P111-136 inhibits significantly the PC-3 tumour growth in the xenograft model as well as tumour angiogenesis. The angiostatic effect of P111-136 on HARP was also confirmed using an in vivo Matrigel™ plug assay in mice Conclusions Our results demonstrate that P111-136 strongly inhibits the mitogenic effect of HARP on in vitro and in vivo growth of PC-3 cells. This inhibition could be linked to a direct or indirect binding of this peptide to the HARP receptors (ALK, RPTP

  9. Structural basis for the interaction of a vascular endothelial growth factor mimic peptide motif and its corresponding receptors.

    PubMed

    Giordano, Ricardo J; Anobom, Cristiane D; Cardó-Vila, Marina; Kalil, Jorge; Valente, Ana P; Pasqualini, Renata; Almeida, Fabio C L; Arap, Wadih

    2005-10-01

    Vascular endothelial growth factor (VEGF) is central to the survival and development of the vascular and nervous systems. We screened phage display libraries and built a peptide-based ligand-receptor map of binding sites within the VEGF family. We then validated a cyclic peptide, CPQPRPLC, as a VEGF-mimic that binds specifically to neuropilin-1 and VEGF receptor-1. Here, we use NMR spectroscopy to understand the structural basis of the interaction between our mimic peptide and the VEGF receptors. We show that: (1) CPQPRPLC has multiple interactive conformations; (2) receptor binding is mediated by the motif Arg-Pro-Leu; and (3) the Pro residue within Arg-Pro-Leu participates in binding to neuropilin-1 but not to VEGF receptor-1, perhaps representing an evolutionary gain-of-function. Therefore, Arg-Pro-Leu is a differential ligand motif to VEGF receptors and a candidate peptidomimetic lead for VEGF pathway modulation.

  10. Intestinotrophic Glucagon-Like Peptide-2 (GLP-2) Activates Intestinal Gene Expression and Growth Factor-Dependent Pathways Independent of the Vasoactive Intestinal Peptide Gene in Mice

    PubMed Central

    Yusta, Bernardo; Holland, Dianne; Waschek, James A.

    2012-01-01

    The enteroendocrine and enteric nervous systems convey signals through an overlapping network of regulatory peptides that act either as circulating hormones or as localized neurotransmitters within the gastrointestinal tract. Because recent studies invoke an important role for vasoactive intestinal peptide (VIP) as a downstream mediator of glucagon-like peptide-2 (GLP-2) action in the gut, we examined the importance of the VIP-GLP-2 interaction through analysis of Vip−/− mice. Unexpectedly, we detected abnormal villous architecture, expansion of the crypt compartment, increased crypt cell proliferation, enhanced Igf1 and Kgf gene expression, and reduced expression of Paneth cell products in the Vip−/− small bowel. These abnormalities were not reproduced by antagonizing VIP action in wild-type mice, and VIP administration did not reverse the intestinal phenotype of Vip−/− mice. Exogenous administration of GLP-2 induced the expression of ErbB ligands and immediate-early genes to similar levels in Vip+/+ vs. Vip−/− mice. Moreover, GLP-2 significantly increased crypt cell proliferation and small bowel growth to comparable levels in Vip+/+ vs. Vip−/− mice. Unexpectedly, exogenous GLP-2 administration had no therapeutic effect in mice with dextran sulfate-induced colitis; the severity of colonic injury and weight loss was modestly reduced in female but not male Vip−/− mice. Taken together, these findings extend our understanding of the complex intestinal phenotype arising from loss of the Vip gene. Furthermore, although VIP action may be important for the antiinflammatory actions of GLP-2, the Vip gene is not required for induction of a gene expression program linked to small bowel growth after enhancement of GLP-2 receptor signaling. PMID:22535770

  11. Intracellular protein delivery activity of peptides derived from insulin-like growth factor binding proteins 3 and 5

    SciTech Connect

    Goda, Natsuko; Tenno, Takeshi; Inomata, Kosuke; Shirakawa, Masahiro; Tanaka, Toshiki; Hiroaki, Hidekazu

    2008-08-01

    Insulin-like growth factor binding proteins (IGFBPs) have various IGF-independent cellular activities, including receptor-independent cellular uptake followed by transcriptional regulation, although mechanisms of cellular entry remain unclear. Herein, we focused on their receptor-independent cellular entry mechanism in terms of protein transduction domain (PTD) activity, which is an emerging technique useful for clinical applications. The peptides of 18 amino acid residues derived from IGFBP-3 and IGFBP-5, which involve heparin-binding regions, mediated cellular delivery of an exogenous protein into NIH3T3 and HeLa cells. Relative protein delivery activities of IGFBP-3/5-derived peptides were approximately 20-150% compared to that of the HIV-Tat peptide, a potent PTD. Heparin inhibited the uptake of the fusion proteins with IGFBP-3 and IGFBP-5, indicating that the delivery pathway is heparin-dependent endocytosis, similar to that of HIV-Tat. The delivery of GST fused to HIV-Tat was competed by either IGFBP-3 or IGFBP-5-derived synthetic peptides. Therefore, the entry pathways of the three PTDs are shared. Our data has shown a new approach for designing protein delivery systems using IGFBP-3/5 derived peptides based on the molecular mechanisms of IGF-independent activities of IGFBPs.

  12. In vitro selection of a peptide antagonist of growth hormone secretagogue receptor using cDNA display

    PubMed Central

    Ueno, Shingo; Yoshida, Sayaka; Mondal, Anupom; Nishina, Kazuya; Koyama, Makoto; Sakata, Ichiro; Miura, Kenju; Hayashi, Yujiro; Nemoto, Naoto; Nishigaki, Koichi; Sakai, Takafumi

    2012-01-01

    G protein-coupled receptors (GPCRs) are major drug targets, and their ligands are currently being explored and developed by many pharmaceutical companies and independent researchers. Class A (rhodopsin-like) GPCRs compose a predominant GPCR family; therefore, class A GPCR ligands are in demand. Growth hormone secretagogue receptor (GHS-R) is a class A GPCR that stimulates food intake by binding to its peptide ligand, ghrelin. Therefore, antagonists of GHS-R are expected to exert antiobesity function. In this article, we describe the use of cDNA display to screen for successfully and identify an antagonistic peptide of GHS-R. The antagonistic peptide inhibited the ghrelin-induced increase in intracellular Ca2+ in vitro (IC50 = approximately 10 μM) and repressed the contraction of isolated animal stomach in response to ghrelin. Furthermore, peripheral administration of the peptide inhibited the food intake of mice. This work provides new insight into the development of antiobesity drugs and describes a method for the discovery of unique peptide ligands for class A GPCRs. PMID:22723348

  13. Evaluation of Recombinant Human Growth Hormone Secretion in E. coli using the L-asparaginase II Signal Peptide

    PubMed Central

    Zamani, Mozhdeh; Nezafat, Navid; Ghasemi, Younes

    2016-01-01

    Background: In the recent years, there has been an increasing interest in secretory production of recombinant proteins, due to its various advantages compared with intracellular expression. Signal peptides play a critical role in prosperous secretion of recombinant proteins. Accordingly, different signal peptides have been assessed for their ability to produce secretory proteins by trial-and-error experiments. The aim of this study was to evaluate the effect of L-asparaginase II signal peptide on the recombinant human Growth Hormone (hGH) protein secretion in the Escherichia coli (E. coli) host. Methods: Cloning and expression of a synthetic hGH gene, containing L-asparaginase II signal sequence was performed in E. coli BL21 (DE3) using 0.1mM IPTG as an inducer at 23°C overnight. Periplasmic protein extraction was performed using three methods, including osmotic shock, osmotic shock in the presence of glycine and combined Lysozyme/EDTA osmotic shock. Afterwards, the hGH expression was determined by SDS-PAGE. Results: Based on experimentally obtained results, hGH protein is expressed as inclusion body even in the presence of L-asparaginase II signal peptide. Conclusion: Therefore, this signal peptide is not effective for secretory production of the recombinant hGH. PMID:27920886

  14. Molecularly targeted nanocarriers deliver the cytolytic peptide melittin specifically to tumor cells in mice, reducing tumor growth.

    PubMed

    Soman, Neelesh R; Baldwin, Steven L; Hu, Grace; Marsh, Jon N; Lanza, Gregory M; Heuser, John E; Arbeit, Jeffrey M; Wickline, Samuel A; Schlesinger, Paul H

    2009-09-01

    The in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, nonspecificity, and degradation. We previously developed a specific strategy to synthesize a nanoscale delivery vehicle for cytolytic peptides by incorporating the nonspecific amphipathic cytolytic peptide melittin into the outer lipid monolayer of a perfluorocarbon nanoparticle. Here, we have demonstrated that the favorable pharmacokinetics of this nanocarrier allows accumulation of melittin in murine tumors in vivo and a dramatic reduction in tumor growth without any apparent signs of toxicity. Furthermore, direct assays demonstrated that molecularly targeted nanocarriers selectively delivered melittin to multiple tumor targets, including endothelial and cancer cells, through a hemifusion mechanism. In cells, this hemifusion and transfer process did not disrupt the surface membrane but did trigger apoptosis and in animals caused regression of precancerous dysplastic lesions. Collectively, these data suggest that the ability to restrain the wide-spectrum lytic potential of a potent cytolytic peptide in a nanovehicle, combined with the flexibility of passive or active molecular targeting, represents an innovative molecular design for chemotherapy with broad-spectrum cytolytic peptides for the treatment of cancer at multiple stages.

  15. Molecularly targeted nanocarriers deliver the cytolytic peptide melittin specifically to tumor cells in mice, reducing tumor growth

    PubMed Central

    Soman, Neelesh R.; Baldwin, Steven L.; Hu, Grace; Marsh, Jon N.; Lanza, Gregory M.; Heuser, John E.; Arbeit, Jeffrey M.; Wickline, Samuel A.; Schlesinger, Paul H.

    2009-01-01

    The in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, nonspecificity, and degradation. We previously developed a specific strategy to synthesize a nanoscale delivery vehicle for cytolytic peptides by incorporating the nonspecific amphipathic cytolytic peptide melittin into the outer lipid monolayer of a perfluorocarbon nanoparticle. Here, we have demonstrated that the favorable pharmacokinetics of this nanocarrier allows accumulation of melittin in murine tumors in vivo and a dramatic reduction in tumor growth without any apparent signs of toxicity. Furthermore, direct assays demonstrated that molecularly targeted nanocarriers selectively delivered melittin to multiple tumor targets, including endothelial and cancer cells, through a hemifusion mechanism. In cells, this hemifusion and transfer process did not disrupt the surface membrane but did trigger apoptosis and in animals caused regression of precancerous dysplastic lesions. Collectively, these data suggest that the ability to restrain the wide-spectrum lytic potential of a potent cytolytic peptide in a nanovehicle, combined with the flexibility of passive or active molecular targeting, represents an innovative molecular design for chemotherapy with broad-spectrum cytolytic peptides for the treatment of cancer at multiple stages. PMID:19726870

  16. Regulation of growth-blocking peptide expression during embryogenesis of the cabbage army worm

    SciTech Connect

    Tsuzuki, Seiji; Sekiguchi, Shiroh; Hayakawa, Yoichi . E-mail: hayakayo@cc.saga-u.ac.jp

    2005-10-07

    Growth-blocking peptide (GBP) is an insect cytokine with diverse biological functions. Northern blot analysis revealed high heterogeneity in the size distribution of GBP mRNAs as well as in the tissues where they are detected. The s patio-temporal transcription pattern is dynamic, especially during embryogenesis. Gel shift assays demonstrated that the cabbage army worm embryo nuclear extract specifically binds to a 178-bp element, at position +234 to +411 from the transcription start site of the 1.3 kb GBP transcript, in which two Drosophila Deformed (DfD) binding sites are repeated in tandem. The specific binding between this element and Dfd was demonstrated using recombinant cabbage armyworm Dfd protein. Silencing the Dfd expression in embryos by treating with DfD double-stranded RNA did not reduce the expression level of GBP, but ectopic GBP expression was observed in the lateral region of the embryo, suggesting that DD could serve as a transcriptional repressor for the GBP gene.

  17. The Host Defense Peptide Cathelicidin Is Required for NK Cell-Mediated Suppression of Tumor Growth

    PubMed Central

    Büchau, Amanda S.; Morizane, Shin; Trowbridge, Janet; Schauber, Jürgen; Kotol, Paul; Bui, Jack D.; Gallo, Richard L.

    2010-01-01

    Tumor surveillance requires the interaction of multiple molecules and cells that participate in innate and the adaptive immunity. Cathelicidin was initially identified as an antimicrobial peptide, although it is now clear that it fulfills a variety of immune functions beyond microbial killing. Recent data have suggested contrasting roles for cathelicidin in tumor development. Because its role in tumor surveillance is not well understood, we investigated the requirement of cathelicidin in controlling transplantable tumors in mice. Cathelicidin was observed to be abundant in tumor-infiltrating NK1.1+ cells in mice. The importance of this finding was demonstrated by the fact that cathelicidin knockout mice (Camp−/−) permitted faster tumor growth than wild type controls in two different xenograft tumor mouse models (B16.F10 and RMA-S). Functional in vitro analyses found that NK cells derived from Camp−/− versus wild type mice showed impaired cytotoxic activity toward tumor targets. These findings could not be solely attributed to an observed perforin deficiency in freshly isolated Camp−/− NK cells, because this deficiency could be partially restored by IL-2 treatment, whereas cytotoxic activity was still defective in IL-2-activated Camp−/− NK cells. Thus, we demonstrate a previously unrecognized role of cathelicidin in NK cell antitumor function. PMID:19949065

  18. Coal Fly Ash Impairs Airway Antimicrobial Peptides and Increases Bacterial Growth

    PubMed Central

    Borcherding, Jennifer A.; Chen, Haihan; Caraballo, Juan C.; Baltrusaitis, Jonas; Pezzulo, Alejandro A.; Zabner, Joseph; Grassian, Vicki H.; Comellas, Alejandro P.

    2013-01-01

    Air pollution is a risk factor for respiratory infections, and one of its main components is particulate matter (PM), which is comprised of a number of particles that contain iron, such as coal fly ash (CFA). Since free iron concentrations are extremely low in airway surface liquid (ASL), we hypothesize that CFA impairs antimicrobial peptides (AMP) function and can be a source of iron to bacteria. We tested this hypothesis in vivo by instilling mice with Pseudomonas aeruginosa (PA01) and CFA and determine the percentage of bacterial clearance. In addition, we tested bacterial clearance in cell culture by exposing primary human airway epithelial cells to PA01 and CFA and determining the AMP activity and bacterial growth in vitro. We report that CFA is a bioavailable source of iron for bacteria. We show that CFA interferes with bacterial clearance in vivo and in primary human airway epithelial cultures. Also, we demonstrate that CFA inhibits AMP activity in vitro, which we propose as a mechanism of our cell culture and in vivo results. Furthermore, PA01 uses CFA as an iron source with a direct correlation between CFA iron dissolution and bacterial growth. CFA concentrations used are very relevant to human daily exposures, thus posing a potential public health risk for susceptible subjects. Although CFA provides a source of bioavailable iron for bacteria, not all CFA particles have the same biological effects, and their propensity for iron dissolution is an important factor. CFA impairs lung innate immune mechanisms of bacterial clearance, specifically AMP activity. We expect that identifying the PM mechanisms of respiratory infections will translate into public health policies aimed at controlling, not only concentration of PM exposure, but physicochemical characteristics that will potentially cause respiratory infections in susceptible individuals and populations. PMID:23469047

  19. Neuroactive Peptides as Putative Mediators of Antiepileptic Ketogenic Diets

    PubMed Central

    Giordano, Carmela; Marchiò, Maddalena; Timofeeva, Elena; Biagini, Giuseppe

    2014-01-01

    Various ketogenic diet (KD) therapies, including classic KD, medium chain triglyceride administration, low glycemic index treatment, and a modified Atkins diet, have been suggested as useful in patients affected by pharmacoresistant epilepsy. A common goal of these approaches is to achieve an adequate decrease in the plasma glucose level combined with ketogenesis, in order to mimic the metabolic state of fasting. Although several metabolic hypotheses have been advanced to explain the anticonvulsant effect of KDs, including changes in the plasma levels of ketone bodies, polyunsaturated fatty acids, and brain pH, direct modulation of neurotransmitter release, especially purinergic (i.e., adenosine) and γ-aminobutyric acidergic neurotransmission, was also postulated. Neuropeptides and peptide hormones are potent modulators of synaptic activity, and their levels are regulated by metabolic states. This is the case for neuroactive peptides such as neuropeptide Y, galanin, cholecystokinin, and peptide hormones such as leptin, adiponectin, and growth hormone-releasing peptides (GHRPs). In particular, the GHRP ghrelin and its related peptide des-acyl ghrelin are well-known controllers of energy homeostasis, food intake, and lipid metabolism. Notably, ghrelin has also been shown to regulate the neuronal excitability and epileptic activation of neuronal networks. Several lines of evidence suggest that GHRPs are upregulated in response to starvation and, particularly, in patients affected by anorexia and cachexia, all conditions in which also ketone bodies are upregulated. Moreover, starvation and anorexia nervosa are accompanied by changes in other peptide hormones such as adiponectin, which has received less attention. Adipocytokines such as adiponectin have also been involved in modulating epileptic activity. Thus, neuroactive peptides whose plasma levels and activity change in the presence of ketogenesis might be potential candidates for elucidating the neurohormonal

  20. Gut hormone release and appetite regulation in healthy non-obese participants following oligofructose intake. A dose-escalation study.

    PubMed

    Pedersen, Camilla; Lefevre, Solenne; Peters, Véronique; Patterson, Michael; Ghatei, Mohammad A; Morgan, Linda M; Frost, Gary S

    2013-07-01

    Prevention of weight gain in adults is a major public health target. Animal experiments have consistently demonstrated a relationship between fermentable carbohydrate intake, such as oligofructose, anorectic gut hormones, and appetite suppression and body weight control. This study was designed to determine the dose of oligofructose which would augment the release of anorectic gut hormones and reduce appetite consistently in non-obese humans. Twelve non-obese participants were recruited for a 5-week dose-escalation study. Following a 9-14-day run-in, participants increased their daily oligofructose intake every week from 15, 25, 35, 45, to 55 g daily. Subjective appetite and side effects were monitored daily. Three-day food diaries were completed every week. Appetite study sessions explored the acute effects of 0, 15, 35, and 55 g oligofructose on appetite-related hormones, glycaemia, subjective appetite, and energy intake. In the home environment, oligofructose suppressed hunger, but did not affect energy intake. Oligofructose dose-dependently increased peptide YY, decreased pancreatic polypeptide and tended to decrease ghrelin, but did not significantly affect appetite profile, energy intake, glucose, insulin, or glucagon-like peptide 1 concentrations during appetite study sessions. In conclusion, oligofructose supplementation at ≥ 35 g/day increased peptide YY and suppressed pancreatic polypeptide and hunger; however, energy intake did not change significantly.

  1. Identification and Evaluation of Cryoprotective Peptides from Chicken Collagen: Ice-Growth Inhibition Activity Compared to That of Type I Antifreeze Proteins in Sucrose Model Systems.

    PubMed

    Du, Lihui; Betti, Mirko

    2016-06-29

    The ability of chicken collagen peptides to inhibit the growth of ice crystals was evaluated and compared to that of fish antifreeze proteins (AFPs). This ice inhibition activity was assessed using a polarized microscope by measuring ice crystal dimensions in a sucrose model system with and without collagen peptides after seven thermal cycles. The system was stabilized at -25 °C and cycled between -16 and -12 °C. Five candidate peptides with ice inhibition activity were identified using liquid chromatography and tandem mass spectrometry and were then synthesized. Their ice inhibition capacity was compared to that of type I AFPs in a 23% sucrose model system. Specific collagen peptides with certain amino acid sequences reduced the extent of ice growth by approximately 70% at a relatively low concentration (1 mg/mL). These results suggest that specific collagen peptides may act in a noncolligative manner, inhibiting ice crystal growth like type I AFPs, but less efficiently.

  2. Fibroblast Growth Factor-Peptide Improves Barrier Function and Proliferation in Human Keratinocytes After Radiation

    SciTech Connect

    Zhang Kunzhong; Tian Yeping; Yin Liangjie; Zhang Mei; Beck, Lisa A.; Zhang, Bingrong; Okunieff, Paul; Zhang Lurong; Vidyasagar, Sadasivan

    2011-09-01

    Purpose: Epidermal keratinocytes, which can be severely damaged after ionizing radiation (IR), are rapid turnover cells that function as a barrier, protecting the host from pathogenic invasion and fluid loss. We tested fibroblast growth factor-peptide (FGF-P), a small peptide derived from the receptor-binding domain of FGF-2, as a potential mitigator of radiation effects via proliferation and the barrier function of keratinocytes. Methods and Materials: Keratinocytes isolated from neonatal foreskin were grown on transwells. After being exposed to 0, 5, or 10 Gy IR, the cells were treated with a vehicle or FGF-P. The permeability of IR cells was assessed by using transepithelial electrical resistance (TEER) and a paracellular tracer flux of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) with Ussing chambers. The cell proliferation was measured with yellow tetrazolium salt (MTT) and tritiated thymidine ([{sup 3}H]-TdR) assays. The phosphorylation of extracellular signal-regulated kinases (ERK) was measured in an enzyme-linked immunosorbent (ELISA)-like assay, and the proteins related to tight junctions (TJ) and adherens junctions (AJ) were examined with Western blotting. We used a mouse model to assess the ability of FGF-P to promote the healing of skin {beta} burns created with a strontium applicator. Results: We found (1) FGF-P reduced the permeability of irradiated keratinocytes, as evidenced by increased TEER and decreased diffusion of FITC-BSA, both associated with the regulation of different proteins and levels of TJ and AJ; and (2) FGF-P enhanced the proliferation of irradiated keratinocytes, as evidenced by increased MTT activity and [{sup 3}H]-TdR incorporation, which was associated with activation of the ERK pathway; and (3) FGF-P promoted the healing of skin {beta} burns. Conclusions: FGF-P enhances the barrier function, including up-regulation of TJ proteins, increases proliferation of human keratinocytes, and accelerates the

  3. Growth of Escherichia coli MG1655 on LB medium: monitoring utilization of amino acids, peptides, and nucleotides with transcriptional microarrays.

    PubMed

    Baev, Mark V; Baev, Dmitry; Radek, Agnes Jansco; Campbell, John W

    2006-07-01

    Analysis of gene expression data related to assimilation and biosynthesis of nitrogen-containing compounds amino acids, peptides, and nucleotides was used to monitor availability of these nutrients to Escherichia coli MG1655 growing on Luria-Bertani medium. The data indicate that free amino acids and nucleotides only transiently support the nitrogen requirement for growth and are no longer available by 3.5 h of fermentation. The resulting shortage of available nitrogen sources induces the Ntr response, which involves induction of the glnALG, glnK-amtB, dppABCDF, and oppABCDF operons as well as the genes coding for outer membrane proteins, porins OmpA and OmpC, and proteases OmpP and OmpT. The increased uptake of peptides facilitated by the products of dppABCDF, oppABCDF, ompA, ompC, ompP, and ompT alleviates nitrogen limitation of the growth.

  4. Thiol-Disulfide Exchange in Peptides Derived from Human Growth Hormone during Lyophilization and Storage in the Solid State

    PubMed Central

    Chandrasekhar, Saradha; Topp, Elizabeth M.

    2015-01-01

    Lyophilization (freeze-drying) is frequently used to stabilize protein therapeutics. However, covalent modifications such as thiol-disulfide exchange and disulfide scrambling can occur even in the solid state. The effects of lyophilization and storage of lyophilized powders on the mechanism and kinetics of thioldisulfide exchange have not been elucidated and are explored here. Reaction kinetics were monitored in peptides corresponding to tryptic fragments of human growth hormone (T20 + T20-T21 or T20 + cT20-T21) during different stages of lyophilization and during storage of the lyophilized powders at 22 °C and ambient RH. The concentrations of reactants and products were determined using RP-HPLC and product identity confirmed using LC-MS. Loss of native disulfide was observed for the reaction of T20 with both linear (T20-T21) and cyclic (cT20-T21) peptides during the primary drying step, however, the native disulfides were regenerated during secondary drying with no further change till the end of lyophilization. Deviations from Arrhenius parameters predicted from solution studies and the absence of buffer effects during lyophilization suggest that factors such as temperature, initial peptide concentration, buffer type and concentration do not influence thiol-disulfide exchange during lyophilization. Results from a ‘cold finger’ method used to study peptide adsorption to ice indicate that there is no preferential adsorption to the ice surface and that its presence may not influence disulfide reactivity during primary drying. Overall, reaction rates and product distribution differ for the reaction of T20 with T20-T21 or cT20-T21 in the solid state and aqueous solution, while the mechanism of thiol-disulfide remains unchanged. Increased reactivity of the cyclic peptide in the solid state suggests that peptide cyclization does not offer protection against lyophilization and that damage induced by a process stress further affects storage stability at 22 °C and

  5. Sequence-specific bacterial growth inhibition by peptide nucleic acid targeted to the mRNA binding site of 16S rRNA.

    PubMed

    Hatamoto, Masashi; Nakai, Kazufumi; Ohashi, Akiyoshi; Imachi, Hiroyuki

    2009-10-01

    Peptide nucleic acid (PNA) targeted to the functional domains of 23S rRNA can inhibit translation and cell growth. However, effective inhibition of translation and cell growth using 16S rRNA-targeted PNA has still not been achieved. Here, we report that PNA targeted to the functional site of 16S rRNA could inhibit both gene expression in vitro and bacterial growth in pure culture with sequence specificity. We used 10-mer PNAs conjugated with a cell-penetrating peptide, which targeted the mRNA binding site at the 3' end of 16S rRNA. Using 0.6 microM of the peptide-PNAs, cell-free ss-galactosidase production decreased by 50%, whereas peptide-PNAs with one or two mismatches to the target sequence showed much weaker inhibition effects. To determine the growth inhibition and bactericidal effects of the peptide-PNA conjugate, we performed OD measurement and viable cell counting. We observed dose- and sequence-dependent inhibition of cell growth and bactericidal effects. These growth inhibitory effects are observed both in the Gram-negative bacterium of Escherichia coli and the Gram-positive bacteria Bacillus subtilis and Corynebacterium efficiens, although inhibitory concentrations were different for each bacterial species. These results present possibilities for 16S rRNA sequence-based specific bacterial growth inhibition using a peptide-PNA conjugate.

  6. Surface modification of TiO2 nanotubes with osteogenic growth peptide to enhance osteoblast differentiation.

    PubMed

    Lai, Min; Jin, Ziyang; Su, Zhiguo

    2017-04-01

    To investigate the influence of surface-biofunctionalized substrates on osteoblast behavior, a layer of aligned TiO2 nanotubes with a diameter of around 70nm was fabricated on titanium surface by anodization, and then osteogenic growth peptide (OGP) was conjugated onto TiO2 nanotubes through the intermediate layer of polydopamine. The morphology, composition and wettability of different surfaces were characterized by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements, respectively. The effects of OGP-modified TiO2 nanotube substrates on the morphology, proliferation and differentiation of osteoblasts were examined in vitro. Immunofluorescence staining revealed that the OGP-functionalized TiO2 nanotubes were favorable for cell spreading. However, there was no significant difference in cell proliferation observed among the different groups. Cells grown onto OGP-functionalized TiO2 nanotubes showed significantly higher (p<0.05 or p<0.01) levels of alkaline phosphatase (ALP) and mineralization after 4, 7 and 14days of culture, respectively. Cells grown on OGP-functionalized TiO2 nanotubes had significantly higher (p<0.05 or p<0.01) expression of osteogenic-related genes including runt related transcription factor 2 (Runx2), ALP, collagen type I (Col I), osteopontin (OPN) and osteocalcin (OC) after 14days of culture. These data suggest that surface functionalization of TiO2 nanotubes with OGP was beneficial for cell spreading and differentiation. This study provides a novel platform for the development and fabrication of titanium-based implants that enhance the propensity for osseointegration between the native tissue and implant interface. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Growth of Streptococcus mutans in Biofilms Alters Peptide Signaling at the Sub-population Level

    PubMed Central

    Shields, Robert C.; Burne, Robert A.

    2016-01-01

    Streptococcus mutans activates multiple cellular processes in response to the formation of a complex between comX-inducing peptide (XIP) and the ComR transcriptional regulator. Bulk phase and microfluidic experiments previously revealed that ComR-dependent activation of comX is altered by pH and by carbohydrate source. Biofilm formation is a major factor in bacterial survival and virulence in the oral cavity. Here, we sought to determine the response of S. mutans biofilm cells to XIP during different stages of biofilm maturation. Using flow cytometry and confocal microscopy, we showed that exogenous addition of XIP to early biofilms resulted in robust comX activation. However, as the biofilms matured, increasing amounts of XIP were required to activate comX expression. Single-cell analysis demonstrated that the entire population was responding to XIP with activation of comX in early biofilms, but only a sub-population was responding in mature biofilms. The sub-population response of mature biofilms was retained when the cells were dispersed and then treated with XIP. The proportion and intensity of the bi-modal response of mature biofilm cells was altered in mutants lacking the Type II toxins MazF and RelE, or in a strain lacking the (p)ppGpp synthase/hydrolase RelA. Thus, competence signaling is markedly altered in cells growing in mature biofilms, and pathways that control cell death and growth/survival decisions modulate activation of comX expression in these sessile populations. PMID:27471495

  8. Effects of TRH and somatostatin on releases of prolactin and growth hormone in vitro by the pituitary of Poecilia latipinna. II. Electron-microscopic morphometry using automatic image analysis.

    PubMed

    Batten, T F; Wigham, T

    1984-01-01

    Pituitary glands from a teleost fish were incubated in the presence of the synthetic hypophysiotropic peptides, thyrotrophin-releasing hormone and somatostatin, in two media of different osmotic pressure. The effects on prolactin and growth hormone cells were detected by electron-microscopic morphometry with the aid of an image analyser. Thyrotrophin-releasing hormone caused changes in prolactin cell ultrastructure consistent with stimulated hormone release and, in the low osmotic pressure medium, appeared to increase synthetic activity. There was no effect on growth hormone cells. After somatostatin treatment, both synthesis and release in prolactin cells appeared to be inhibited, and there was an obvious inhibition of synthesis and release in growth hormone cells. The response of both cell types to somatostatin did not appear to be dependent on the osmotic pressure of the medium.

  9. Regulation of Breast Carcinoma Growth and Neovascularization by Novel Peptide Sequences in Thromospondin

    DTIC Science & Technology

    1997-10-01

    permeation chromatography, or reverse phase purification using C18 Sep-pak cartridges. Identities of some peptides were verified by MALDI time of flight...Nine micromoles of peptide were dissolved in 1.8 ml of distilled water , and 250 pl of a 50 mM solution of tris-(2- carboxyethyl) phosphine...hydrochloride (Pierce Chemical) in water was added to the peptide solution, and the pH was adjusted to 7.1 to 7.8 by addition of 1 M Na2CO 3. After 30-60 min

  10. Proteolytic processing of a precursor protein for a growth-promoting peptide by a subtilisin serine protease in Arabidopsis.

    PubMed

    Srivastava, Renu; Liu, Jian-Xiang; Howell, Stephen H

    2008-10-01

    Phytosulfokines (PSKs) are secreted, sulfated peptide hormones derived from larger prepropeptide precursors. Proteolytic processing of one of the precursors, AtPSK4, was demonstrated by cleavage of a preproAtPSK4-myc transgene product to AtPSK4-myc. Cleavage of proAtPSK4 was induced by placing root explants in tissue culture. The processing of proAtPSK4 was dependent on AtSBT1.1, a subtilisin-like serine protease, encoded by one of 56 subtilase genes in Arabidopsis. The gene encoding AtSBT1.1 was up-regulated following the transfer of root explants to tissue culture, suggesting that activation of the proteolytic machinery that cleaves proAtPSK4 is dependent on AtSBT1.1 expression. We also demonstrated that a fluorogenic peptide representing the putative subtilase recognition site in proAtPSK4 is cleaved in vitro by affinity-purified AtSBT1.1. An alanine scan through the recognition site peptide indicated that AtSBT1.1 is fairly specific for the AtPSK4 precursor. Thus, this peptide growth factor, which promotes callus formation in culture, is proteolytically cleaved from its precursor by a specific plant subtilase encoded by a gene that is up-regulated during the process of transferring root explants to tissue culture.

  11. Biomimetic and Aggregation-Driven Crystallization Route for Room-Temperature Material Synthesis: Growth of β-Ga2O3 Nanoparticles Using Peptide Assemblies as Nanoreactors

    PubMed Central

    Lee, Sang-Yup; Gao, Xueyun; Matsui, Hiroshi

    2008-01-01

    The room temperature synthesis of β-Ga2O3 nanocrystal was examined by coupling two biomimetic crystallization techniques, the enzymatic peptide nano-assembly templating and the aggregation-driven crystallization. The catalytic template of peptide assembly nucleated and mineralized primary β-Ga2O3 crystals, and then fused them to grow single-crystalline and monodisperse nanoparticles in the cavity of the peptide assembly at room temperature. In this work, the peptide assembly was exploited as a nano-reactor with an enzymatic functionality catalyzing the hydrolysis of gallium precursors. In addition, the characteristic ring-structure of peptide assembly is expected to provide an efficient dehydration pathway and the crystallization control over the surface tension, which are advantageous for the β-Ga2O3 crystal growth. This multifunctional peptide assembly could be applied for syntheses of a variety of nanomaterials that are kinetically difficult to grow at room temperature. PMID:17302413

  12. Regulation of Breast Carcinoma Growth and Neovacularization by Novel Peptide Sequences In Thromospondin

    DTIC Science & Technology

    1996-10-01

    of DNA fragmentation or using a DNA fragment ELISA (Boehringer Mannheim) after labelling the cells with bromodeoxyuridine and exposure to the peptides...stimulated DNA fragmentation . The basic residues and the WSXW motif were both required for optimal activity of these peptide conjugates, based on the...the cells to 1 pg/ml TSP1 did not result in detectable DNA fragmentation by this method (lane h). An ELISA assay for detecting DNA fragmentation was

  13. TUP1 disruption in Cryptococcus neoformans uncovers a peptide-mediated density-dependent growth phenomenon that mimics quorum sensing.

    PubMed

    Lee, Hyeseung; Chang, Yun C; Nardone, Glenn; Kwon-Chung, Kyung J

    2007-05-01

    Cryptococcus neoformans is a pathogenic yeast that causes life-threatening meningoencephalitis and grows well on mycological media regardless of inoculum size. Interestingly, a deletion of the global repressor TUP1 in C. neoformans uncovered a density-dependent growth phenotype reminiscent of the quorum-sensing phenomenon. An inoculum size of lower than 10(3) cells of the tup1Delta strain failed to form colonies on agar media while inocula of 10(5)-10(6) cells per plate formed a lawn. This phenotype, expressed as the inability to grow at low cell densities, was rescued by the culture filtrate from a high cell density tup1Delta culture and the active molecule in this culture filtrate was identified to be an oligopeptide composed of 11 amino acids. Activity assays, using a synthetic version of the peptide with strains harbouring a deletion of the corresponding gene, proved that the oligopeptide functioned as an autoregulatory molecule responsible for the density-dependent phenotype. Although a density-dependent growth phenotype has been reported in several species of Ascomycetes, no peptide has been reported to function as an autoregulator in the Kingdom Fungi. The identification of an 11-mer peptide as an autoregulatory molecule in C. neoformans suggests that a diverse mechanism of cell-to-cell communication exists in the Kingdom Fungi.

  14. The Growth Hormone Secretagogue Hexarelin Protects Rat Cardiomyocytes From in vivo Ischemia/Reperfusion Injury Through Interleukin-1 Signaling Pathway.

    PubMed

    Huang, Jiannan; Li, Yi; Zhang, Juan; Liu, Yusheng; Lu, Qinghua

    2017-04-06

    Hexarelin, a synthetic growth hormone-releasing peptide, has been proven to possess cardioprotective actions through its binding to the growth hormone secretagogue receptor (GHSR) 1a and the non-GHSR receptor CD36. However, its effect on myocardial ischemia/reperfusion (I/R) injury has not been fully clarified in vivo. We aimed to determine whether hexarelin treatment could protect cardiomyocytes from I/R injury and to examine the underlying mechanisms. In vivo hearts of male SD rats underwent 30 minutes of ischemia by left coronary artery ligation followed by reperfusion. The rats were then treated subcutaneously twice daily with hexarelin [100 μg/kg·day], ghrelin [400 μg/ kg·day], or saline for 7 days. Echocardiography, malondialdehyde detection, and histochemical staining were performed after treatment. In addition, Western blot was used to examine the expression levels of IL-1β, IL-1Ra, and IL-1RI. Our study showed that hexarelin treatment improved cardiac systolic function, decreased malondialdehyde production, and increased the number of surviving cardiomyocytes. The beneficial effects of hexarelin treatment were slightly superior to those of equimolar ghrelin treatment. We meanwhile confirmed that hexarelin induced down-regulation of IL-1β expression and up-regulation of IL-1Ra expression in I/R myocardium, which could be neutralized by the GHSR antagonist [D-Lys3]-growth hormone releasing peptide-6 ([D-Lys3]-GHRP-6). These findings suggest that hexarelin protects in vivo cardiomyocytes from I/R injury partly by modification of the IL-1 signaling pathway through the activation of cardiac GHSR1a receptors.

  15. In vitro effect of. Delta. sup 9 -tetrahydrocannabinol to stimulate somatostatin release and block that of luteinizing hormone-releasing hormone by suppression of the release of prostaglandin E sub 2

    SciTech Connect

    Rettori, V.; Aguila, M.C.; McCann, S.M. ); Gimeno, M.F.; Franchi, A.M. )

    1990-12-01

    Previous in vivo studies have shown that {Delta}{sup 9}-tetrahydrocannabinol (THC), the principal active ingredient in marijuana, can suppress both luteinizing hormone (LH) and growth hormone (GH) secretion after its injection into the third ventricle of conscious male rats. The present studies were deigned to determine the mechanism of these effects. Various doses of THC were incubated with either stalk median eminence fragments (MEs) or mediobasal hypothalamic (MBH) fragments in vitro. Although THC (10 nM) did not alter basal release of LH-releasing hormone (LHRH) from MEs in vitro, it completely blocked the stimulatory action of dopamine or nonrepinephrine on LHRH release. The effective doses to block LHRH release were associated with a blockade of synthesis and release of prostaglandin E{sub 2} (PGE{sub 2}) from MBH in vitro. In contrast to the suppressive effect of THC on LHRH release, somatostatin release from MEs was enhanced in a dose-related manner with a minimal effective dose of 1 nM. Since PGE{sub 2} suppresses somatostatin release, this enhancement may also be related to the suppressive effect of THC on PGE{sub 2} synthesis and release. The authors speculate that these actions are mediated by the recently discovered THC receptors in the tissue. The results indicate that the suppressive effect of THC on LH release is mediated by a blockade of LHRH release, whereas the suppressive effect of the compound on growth hormone release is mediated, at least in part, by a stimulation of somatostatin release.

  16. Effects of a luteinizing hormone-releasing hormone agonist on cognitive, sexual, and hormonal functions in patients with prostate cancer: relationship with testicular and adrenal androgen levels.

    PubMed

    Okamoto, Kohei; Sekine, Yositaka; Nomura, Masashi; Koike, Hidekazu; Matsui, Hiroshi; Shibata, Yasuhiro; Ito, Kazuto; Suzuki, Kazuhiro

    2015-01-01

    To assess the cognitive and sexual/hormonal functioning of prostate cancer patients treated with a luteinizing hormone-releasing hormone (LH-RH) agonist, and the relationships thereof with adrenal and residual testicular androgen levels. Previously, we reported the effect of a luteinizing hormone-releasing hormone (LH-RH) agonist on testicular and adrenal androgen production in patients with prostate cancer. A 6-month treatment with an LH-RH agonist significantly reduced testicular androgens by 90-95% and adrenal androgens by 26-40%. This study evaluated the changes in cognitive and sexual/hormonal functions in the same cohort using the Mini-Mental State Evaluation (MMSE) and Expanded Prostate Cancer Index Composite (EPIC) questionnaire, respectively. In addition, the associations of each function with the serum testosterone (T), dihydrotestosterone (DHT), estradiol (E2), dehydroepiandrosterone-sulfate (DHEA-S), dehydroepiandrosterone (DHEA), androstenedione (A-dione), and cortisol levels were studied. Cognitive functions did not change significantly during the treatment. Sexual functions were relatively low before treatment and worsened significantly after 6 and 12 months of treatment. Interestingly, sexual bothers were improved with the treatment. The treatment significantly worsened hormonal functions and bothers. Regarding specific items in the hormonal domains, hot flashes and body weight changes were the main effects of worsened hormonal function. Low levels of T and E2 and high levels of A-dione were associated with low MMSE scores at 6 months. Regarding sexual and hormonal functions, A-dione, E2, T, cortisol, and DHEA-S were associated with poorer functioning and bother. Especially, low T levels and high E2 levels were the most significant factors associated with worse sexual and hormonal bothers. The LH-RH agonist monotherapy worsened sexual and hormonal functions and hormonal bothers, but not sexual bothers or cognitive functions. The changes in these

  17. Effects of varying combinations of intraduodenal lipid and carbohydrate on antropyloroduodenal motility, hormone release, and appetite in healthy males.

    PubMed

    Seimon, Radhika V; Feltrin, Kate L; Meyer, James H; Brennan, Ixchel M; Wishart, Judith M; Horowitz, Michael; Feinle-Bisset, Christine

    2009-04-01

    Intraduodenal infusions of both lipid and glucose modulate antropyloroduodenal motility and stimulate plasma CCK, with lipid being more potent than glucose. Both stimulate glucagon-like peptide-1, but only lipid stimulates peptide YY (PYY), while only glucose raises blood glucose and stimulates insulin. When administered in combination, lipid and carbohydrate may, thus, have additive effects on energy intake. However, elevated blood glucose levels do not suppress energy intake, and the effect of insulin is controversial. We hypothesized that increasing the ratio of maltodextrin, a complex carbohydrate, relative to lipid would be associated with a reduction in effects on antropyloroduodenal pressures, gut hormones, appetite, and energy intake, when compared with lipid alone. Ten healthy males were studied on three occasions in double-blind, randomized order. Antropyloroduodenal pressures, plasma CCK, PYY and insulin, blood glucose, and appetite were measured during 90-min intraduodenal infusions of 1) 3 kcal/min lipid (L3), 2) 2 kcal/min lipid and 1 kcal/min maltodextrin (L2/CHO1), or 3) 1 kcal/min lipid and 2 kcal/min maltodextrin (L1/CHO2). Energy intake at a buffet lunch consumed immediately after the infusion was quantified. Reducing the lipid (thus, increasing the carbohydrate) content of the infusion was associated with reduced stimulation of basal pyloric pressures (r = 0.76, P < 0.01), plasma CCK (r = 0.66, P < 0.01), and PYY (r = 0.98, P < 0.001), and reduced suppression of antral (r = -0.64, P < 0.05) and duodenal (r = -0.69, P < 0.05) pressure waves, desire-to-eat (r = -0.8, P < 0.001), and energy intake (r = 0.74, P < 0.01), with no differences in phasic (isolated) pyloric pressures. In conclusion, in healthy males, intraduodenal lipid is a more potent modulator of gut function, associated with greater suppression of energy intake, when compared with isocaloric combinations of lipid and maltodextrin.

  18. Effect of the antimicrobial peptide D-Nal-Pac-525 on the growth of Streptococcus mutans and its biofilm formation.

    PubMed

    Li, Huajun; Cheng, Jya-Wei; Yu, Hui-Yuan; Xin, Yi; Tang, Li; Ma, Yufang

    2013-08-01

    Streptococcus mutans is the primary etiological agent of dental caries. The antimicrobial peptide D-Nal-Pac-525 was designed by replacing the tryptophans of the Trp-rich peptide Pac-525 with D-β-naphthyalanines. To assess the effect of D-Nal-Pac-525 on cariogenic bacteria, the activity of D-Nal-Pac-525 on the growth of S. mutans and its biofilm formation were examined. D-Nal- Pac-525 showed robust antimicrobial activity against S. mutans (minimum inhibitory concentration of 4 μg/ml). Using scanning electron microscopy and transmission electron microscopy, it was shown that D-Nal-Pac-525 caused morphological changes and damaged the cell membrane of S. mutans. D-Nal-Pac-525 inhibited biofilm formation of S. mutans at 2 μg/ml. The results of this study suggest that D-Nal-Pac-525 has great potential for clinical application as a dental caries-preventing agent.

  19. Effects of growth hormone-releasing factor (GRF), somatostatin (SRIF) and glucose on growth hormone (GH) secretion in lactating dairy cows

    SciTech Connect

    Sartin, J.L.; Kemppainen, R.J.; Cummins, K.A.

    1986-03-01

    Lactation in dairy cows is associated with increased GH concentrations and high milk production. This study was begun to examine hypothalamic and pituitary sensitivity to GH secretory stimuli. In experiment 1, cows (nonlactating, NL; days 30 and 90 postpartum, pp) fitted with jugular cannulas were administered GRF (n = 10; .08 or .4 ug/kg BW) on successive days or were administered a loading dose of glucose and infused with the same .56 mmol/kg dose for 20 min. In experiment 2, cows (n = 5; days 5 and 30 pp) were infused with saline or SRIF (.2 or .8 mg/kg). After 15 min of infusion, cows were injected with GRF (.1 ug/kg). Plasma was collected and assayed for GH by radioimmunoassay. Data were analyzed by analysis of variance. In experiment 1, glucose had no effect on GH in NL or day 90 cows but increased GH in day 30 cows (p < .05). GRF stimulated GH in all groups but no dose effect was seen at day 30. There was a greater GRF effect at day 90 than in NL cows (p < .05). In experiment 2, GRF had a greater effect at day 30 than day 5 (p < .05). SRIF at both doses slightly blocked GRF actions at day 30 but only the .8 dose blocked GRF actions at day 5 (p < .05). Greater pulses of SRIF with greater sensitivity to suppression by glucose in early lactation could explain the glucose and GRF data. Increased pituitary sensitivity to SRIF but lower SRIF levels may be present in late lactation.

  20. Metabolic Effects of a Growth Hormone-Releasing Factor in Obese Subjects with Reduced Growth Hormone Secretion: A Randomized Controlled Trial

    PubMed Central

    Makimura, Hideo; Feldpausch, Meghan N.; Rope, Alison M.; Hemphill, Linda C.; Torriani, Martin; Lee, Hang

    2012-01-01

    Context: Obesity is associated with reduced GH secretion and increased cardiovascular disease risk. Objective: We performed this study to determine the effects of augmenting endogenous GH secretion on body composition and cardiovascular disease risk indices in obese subjects with reduced GH secretion. Design, Patients and Methods: A randomized, double-blind, placebo-controlled study was performed involving 60 abdominally obese subjects with reduced GH secretion. Subjects received tesamorelin, a GHRH1–44 analog, 2 mg once daily, or placebo for 12 months. Abdominal visceral adipose tissue (VAT) was assessed by abdominal computed tomography scan, and carotid intima-media thickness (cIMT) was assessed by ultrasound. Treatment effect was determined by longitudinal linear mixed-effects modeling. Results: VAT [−16 ± 9 vs.19 ± 9 cm2, tesamorelin vs. placebo; treatment effect (95% confidence interval): −35 (−58, −12) cm2; P = 0.003], cIMT (−0.03 ± 0.01 vs. 0.01 ± 0.01 mm; −0.04 (−0.07, −0.01) mm; P = 0.02), log C-reactive protein (−0.17 ± 0.04 vs. −0.03 ± 0.05 mg/liter; −0.15 (−0.30, −0.01) mg/liter, P = 0.04), and triglycerides (−26 ± 16 vs. 12 ± 8 mg/dl; −37 (−67, −7) mg/dl; P = 0.02) improved significantly in the tesamorelin group vs. placebo. No significant effects on abdominal sc adipose tissue (−6 ± 6 vs. 3 ± 11 cm2; −10 (−32, +13) cm2; P = 0.40) were seen. IGF-I increased (86 ± 21 vs. −6 ± 8 μg/liter; 92 (+52, +132) μg/liter; P < 0.0001). No changes in fasting, 2-h glucose, or glycated hemoglobin were seen. There were no serious adverse events or differences in adverse events between the groups. Conclusion: Among obese subjects with relative reductions in GH, tesamorelin selectively reduces VAT without significant effects on sc adipose tissue and improves triglycerides, C-reactive protein, and cIMT, without aggravating glucose. PMID:23015655

  1. Mass spectrometric identification, sequence evolution, and intraspecific variability of dimeric peptides encoded by cockroach akh genes.

    PubMed

    Sturm, Sebastian; Predel, Reinhard

    2015-02-01

    Neuropeptides are structurally the most diverse group of messenger molecules of the nervous system. Regarding neuropeptide identification, distribution, function, and evolution, insects are among the best studied invertebrates. Indeed, more than 100 neuropeptides are known from single species. Most of these peptides can easily be identified by direct tissue or cell profiling using MALDI-TOF MS. In these experiments, protein hormones with extensive post-translational modifications such as inter- and intramolecular disulfides are usually missed. It is evident that an exclusion of these bioactive molecules hinders the utilization of direct profiling methods in comprehensive peptidomic analyses. In the current study, we focus on the detection and structural elucidation of homo- and heterodimeric adipokinetic hormone precursor-related peptides (APRPs) of cockroaches. The physiological relevance of these molecules with highly conserved sequences in insects is still uncertain. Sequence similarities with vertebrate growth hormone-releasing factors have been reported, but remarkably, few data regarding APRP processing exist and these data are restricted to locusts. Here, we elucidated sequences of carbamidomethylated APRP monomers of different cockroaches by means of MALDI-TOF MS(2), and we were able to identify a surprisingly large number of APRP sequences, resulting either from intraspecific amino acid substitutions within the APRP sequences or C-terminal truncated APRPs.

  2. Sequences of pituitary and placental lactogenic and growth hormones: evolution from a primordial peptide by gene reduplication.

    PubMed

    Niall, H D; Hogan, M L; Sauer, R; Rosenblum, I Y; Greenwood, F C

    1971-04-01

    Human placental lactogen has been found to resemble human pituitary growth hormone very closely in amino acid sequence, about 80% of the residues examined being identical in the two molecules when a revised sequence for growth hormone is used as the basis for comparison. The structural features responsible for the differing biological potency of the two hormones may therefore reside in rather limited regions of primary structure. The observation of internal sequence homologies within the pituitary growth hormone and prolactin and the placental lactogen molecules suggests that these polypeptide hormones may have evolved by genetic reduplication from a smaller common ancestral peptide. This finding directs further attention to subfragments of these molecules as possible possessors of intrinsic somatotrophic and lactogenic activity.

  3. The POLARIS Gene of Arabidopsis Encodes a Predicted Peptide Required for Correct Root Growth and Leaf Vascular Patterning

    PubMed Central

    Casson, Stuart A.; Chilley, Paul M.; Topping, Jennifer F.; Evans, I. Marta; Souter, Martin A.; Lindsey, Keith

    2002-01-01

    The POLARIS (PLS) gene of Arabidopsis was identified as a promoter trap transgenic line, showing β-glucuronidase fusion gene expression predominantly in the embryonic and seedling root, with low expression in aerial parts. Cloning of the PLS locus revealed that the promoter trap T-DNA had inserted into a short open reading frame (ORF). Rapid amplification of cDNA ends PCR, RNA gel blot analysis, and RNase protection assays showed that the PLS ORF is located within a short (∼500 nucleotides) auxin-inducible transcript and encodes a predicted polypeptide of 36 amino acid residues. pls mutants exhibit a short-root phenotype and reduced vascularization of leaves. pls roots are hyperresponsive to exogenous cytokinins and show increased expression of the cytokinin-inducible gene ARR5/IBC6 compared with the wild type. pls seedlings also are less responsive to the growth-inhibitory effects of exogenous auxin and show reduced expression of the auxin-inducible gene IAA1 compared with the wild type. The PLS peptide-encoding region of the cDNA partially complements the pls mutation and requires the PLS ORF ATG for activity, demonstrating the functionality of the peptide-encoding ORF. Ectopic expression of the PLS ORF reduces root growth inhibition by exogenous cytokinins and increases leaf vascularization. We propose that PLS is required for correct auxin-cytokinin homeostasis to modulate root growth and leaf vascular patterning. PMID:12172017

  4. Forced Trefoil Factor Family Peptide 3 (TFF3) Expression Reduces Growth, Viability, and Tumorigenicity of Human Retinoblastoma Cell Lines

    PubMed Central

    Winter, Claudia; Pikos, Stefanie; Stephan, Harald; Dünker, Nicole

    2016-01-01

    Trefoil factor family (TFF) peptides have been shown to effect cell proliferation, apoptosis, migration and invasion of normal cells and various cancer cell lines. In the literature TFF peptides are controversially discussed as tumor suppressors and potential tumor progression factors. In the study presented, we investigated the effect of TFF3 overexpression on growth, viability, migration and tumorigenicity of the human retinoblastoma cell lines Y-79, WERI-Rb1, RBL-13 and RBL-15. As revealed by WST-1 and TUNEL assays as well as DAPI and BrdU cell counts, recombinant human TFF3 significantly lowers retinoblastoma cell viability and increases apoptosis levels. Transient TFF3 overexpression likewise significantly increases RB cell apoptosis. Stable, lentiviral TFF3 overexpression lowers retinoblastoma cell viability, proliferation and growth and significantly increases cell death in retinoblastoma cells. Blockage experiments using a broad-spectrum caspase inhibitor and capase-3 immunocytochemistry revealed the involvement of caspases in general and of caspase-3 in particular in TFF3 induced apoptosis in retinoblastoma cell lines. Soft agarose and in ovo chicken chorioallantoic membrane (CAM) assays revealed that TFF3 overexpression influences anchorage independent growth and significantly decreases the size of tumors forming from retinoblastoma cells. Our study demonstrates that forced TFF3 expression exerts a significant pro-apoptotic, anti-proliferative, and tumor suppressive effect in retinoblastoma cells, setting a starting point for new additive chemotherapeutic approaches in the treatment of retinoblastoma. PMID:27626280

  5. The enhancement of osteoblast growth and differentiation in vitro on a peptide hydrogel-polyHIPE polymer hybrid material.

    PubMed

    Bokhari, Maria A; Akay, Galip; Zhang, Shuguang; Birch, Mark A

    2005-09-01

    The objective of this study was to investigate the effect of combining two biomaterials on osteoblast proliferation, differentiation and mineralised matrix formation in vitro. The first biomaterial has a well-defined architecture and is known as PolyHIPE polymer (PHP). The second biomaterial is a biologically inspired self-assembling peptide hydrogel (RAD16-I, also called PuraMatrix) that produces a nanoscale environment similar to native extracellular matrix (ECM). Our work investigates the effect of combining RAD16-I with two types of PHP (HA (Hydroxyapatite)-PHP and H (Hydrophobic)-PHP) and evaluates effects on osteoblast growth and differentiation. Results demonstrated successful incorporation of RAD16-I into both types of PHP. Osteoblasts were observed to form multicellular layers on the combined biomaterial surface and also within the scaffold. Dynamic cell seeding and culturing techniques were compared to static seeding methods and produced a more even distribution of cells throughout the constructs. Cells were found to penetrate the scaffold to a maximum depth of 3 mm after 35 days in culture. There was a significant increase in cell number in H-PHP constructs coated with RAD16-I compared to H-PHP alone. Our results show that RAD16-I enhances osteoblast differentiation and indicates that the incorporation of this peptide provides a more permissive environment for osteoblast growth. We have developed a microcellular polymer containing a nanoscale environment to enhance cell: biomaterial interactions and promote osteoblast growth in vitro.

  6. A nonpeptidyl growth hormone secretagogue.

    PubMed

    Smith, R G; Cheng, K; Schoen, W R; Pong, S S; Hickey, G; Jacks, T; Butler, B; Chan, W W; Chaung, L Y; Judith, F

    1993-06-11

    A nonpeptidyl secretagogue for growth hormone of the structure 3-amino-3-methyl-N-(2,3,4,5-tetrahydro-2-oxo-1-([2'-(1H-tetrazol-5 -yl) (1,1'-biphenyl)-4-yl]methyl)-1H-1-benzazepin-3(R)-yl)-butanamid e (L-692,429) has been identified. L-692,429 synergizes with the natural growth hormone secretagogue growth hormone-releasing hormone and acts through an alternative signal transduction pathway. The mechanism of action of L-692,429 and studies with peptidyl and nonpeptidyl antagonists suggest that this molecule is a mimic of the growth hormone-releasing hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6). L-692,429 is an example of a nonpeptidyl specific secretagogue for growth hormone.

  7. Effect of dietary macronutrients on postprandial incretin hormone release and satiety in obese and normal-weight women.

    PubMed

    Wikarek, Tomasz; Chudek, Jerzy; Owczarek, Aleksander; Olszanecka-Glinianowicz, Magdalena

    2014-01-28

    The aim of the present study was to assess the effect of dietary macronutrients on postprandial incretin responses and satiety and hunger sensation in obese and normal-weight women. A total of eleven obese and nine normal-weight women were recruited for the assessment of plasma concentrations of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and insulin and the sensation of satiety and hunger using a visual analogue scale before and during a 6 h period after administration of three different macronutrient test meals. The AUCtotal GLP-1 and AUCtotal GIP values were decreased in obese women after the consumption of a fatty meal and all the test meals, respectively. However, the AUCtotal insulin value after a carbohydrate meal was greater in the obese group. The AUCtotal satiety value was decreased only after the intake of the protein meal in obese women when compared with normal-weight women. After the consumption of the fatty meal, a significant positive correlation between maximum satiety sensation and the AUCtotal GLP-1 value in the obese group and that between minimum hunger sensation and the AUCtotal GLP-1 value in the normal-weight group were observed. In conclusion, the findings of the present study suggest that: (1) satiety sensation after consumption of carbohydrate and protein meals in the obese group is related to the postprandial insulin response, while after consumption of a fatty meal, it is related to the postprandial GLP-1 release; (2) the postprandial GIP response does not influence the sensation of satiety and hunger; (3) the reduced GLP-1 release after the intake of a fatty meal in obese individuals may explain impaired satiety sensation; (4) the impaired postprandial GIP response is not related to the consumption of macronutrients and may be the early indicator of incretin axis dysfunction in obese women.

  8. Receptors for luteinizing hormone-releasing hormone (GnRH) as therapeutic targets in triple negative breast cancers (TNBC).

    PubMed

    Kwok, C W; Treeck, O; Buchholz, S; Seitz, S; Ortmann, O; Engel, J B

    2015-09-01

    Triple negative breast cancers express receptors for gonadotropin-releasing hormone (GnRH) in more than 50% of the cases, which can be targeted with peptidic analogs of GnRH, such as triptorelin. The current study investigates cytotoxic activity of triptorelin as a monotherapy and in treatment combinations with chemotherapeutic agents and inhibitors of the PI3K and the ERK pathways in in vitro models of triple negative breast cancers (TNBC). GnRH receptor expression of TNBC cell lines MDA-MB-231 and HCC1806 was investigated. Cells were treated with triptorelin, chemotherapeutic agents (cisplatin, docetaxel, AEZS-112), PI3K/AKT inhibitors (perifosine, AEZS-129), an ERK inhibitor (AEZS-134), and dual PI3K/ERK inhibitor AEZS-136 applied as single agent therapies and in combinations. MDA-MB-231 and HCC1806 TNBC cells both expressed receptors for GnRH on messenger (m)RNA and protein level and were found sensitive to triptorelin with a respective median effective concentration (EC50) of 31.21 ± 0.21 and 58.50 ± 19.50. Synergistic effects occurred when triptorelin was combined with cisplatin. In HCC1806 cells, synergy occurred when triptorelin was applied with PI3K/AKT inhibitors perifosine and AEZS-129. In MDA-MB-231 cells, synergy was observed after co-treatment with triptorelin and ERK inhibitor AEZS-134 and dual PI3K/ERK inhibitor AEZS-136. GnRH receptors on TNBC cells can be used for targeted therapy of these cancers with GnRH agonist triptorelin. Treatment combinations based on triptorelin and PI3K and ERK inhibitors and chemotherapeutic agent cisplatin have synergistic effects in in vitro models of TNBC. If confirmed in vivo, clinical trials based on triptorelin and cisplatin could be quickly carried out, as triptorelin is FDA approved for other indications and known to be well tolerated.

  9. Characterization and in vitro biological evaluation of mineral/osteogenic growth peptide nanocomposites synthesized biomimetically on titanium

    NASA Astrophysics Data System (ADS)

    Chen, Cen; Kong, Xiangdong; Zhang, Sheng-Min; Lee, In-Seop

    2015-04-01

    Nanocomposite layers of mineral/osteogenic growth peptide (OGP) were synthesized on calcium phosphate coated titanium substrates by immersing in calcium-phosphate buffer solution containing OGP. Peptide incorporated mineral was characterized by determining quantity loaded, effects on mineral morphology and structure. Also, the biological activity was investigated by cell adhesion, proliferation assay, and measurement of alkaline phosphatase (ALP) activity. X-ray photoelectron spectroscopy (XPS) and micro-bicinchoninic acid (BCA) assay revealed that OGP was successfully incorporated with mineral and the amount was increased with immersion time. Incorporated OGP changed the mineral morphology from sharp plate-like shape to more rounded one, and the octacalcium phosphate structure of the mineral was gradually transformed into apatite. With confocal microscopy to examine the incorporation of fluorescently labeled peptide, OGP was evenly distributed throughout mineral layers. Mineral/OGP nanocomposites promoted cell adhesion and proliferation, and also increased ALP activity of mesenchymal stem cells (MSCs). Results presented here indicated that the mineral/OGP nanocomposites formed on titanium substrates had the potential for applications in dental implants.

  10. A pH-dependent Antibacterial Peptide Release Nano-system Blocks Tumor Growth in vivo without Toxicity.

    PubMed

    Cao, Jing; Zhang, Yan; Shan, Yanke; Wang, Jingui; Liu, Fei; Liu, Hongrui; Xing, Gang; Lei, Jing; Zhou, Jiyong

    2017-09-11

    In this study, we designed a nano-system where a novel antibacterial peptide RGD-hylin a1 with reduced hemolysis than the commonly studied melittin was loaded onto mesoporous silica (HMS). We found out that the designed nano-system, RGD-hylin a1-HMS, released RGD-hylin a1 in a pH-dependent manner. It caused apoptosis of cancer cells at low dosage of the antibacterial peptide at pH = 5.5, but was safe to the cells at pH = 7. The hemolytic activity of RGD-hylin a1 itself was reduced by 50~100% by the nano-system depending on the dosage. When this nano-system was administered to tumor-bearing mice at low dosage via intravenous injection, the growth of the solid tumor was blocked by the RGD-hylin a1-HMS nano-system with a 50-60% inhibition rate relative to the PBS-treated control group in terms of tumor volume and weight. Further, the hemolytic activity of RGD-hylin a1 was completely eliminated within the delivery system with no other side effects observed. This study demonstrates that this smart pH-dependent antibacterial peptide release nano-system has superior potential for solid tumor treatments through intravenous administration. This smart-releasing system has great potential in further clinical applications.

  11. Purification and identification of a growth-stimulating peptide for Bifidobacterium bifidum from natural rubber serum powder.

    PubMed

    Etoh, S; Asamura, K; Obu, A; Sonomoto, K; Ishizaki, A

    2000-10-01

    Natural rubber serum powder, which is a by-product obtained in the production of latex rubber, has a strong growth-stimulating activity for Bifidobacterium bifidum JCM 1254. The retained fraction obtained by ultrafiltration (molecular weight cutoff 1000) showed a growth-stimulating activity in a dose-dependent manner on B12 assay medium with ammonium sulfate. One of the growth stimulators was purified from the retained fraction by acetone precipitation, solid-phase extraction with a hydrophobic pretreatment column, and multistage reversed-phase HPLC. An increase of 53-fold in the specific activity, and a recovery of 1.3% were obtained. The amino acid composition and N-terminal sequence analysis of this growth stimulator provided the structure of Ala-Thr-Pro-Glu-Lys-Glu-Glu-Pro-Thr-Ala. The molecular mass was 1075 by MALDI-TOF MS analysis. These results showed that this growth stimulator was a decapeptide with the sequence shown above. This is the first report that clarified the structure of an active peptide for the growth of Bifidobacterium.

  12. Transgenic tobacco expressing a modified spider peptide inhibits the growth of plant pathogens and insect larvae

    USDA-ARS?s Scientific Manuscript database

    The gene encoding lycotoxin I, an amphipathic pore-forming peptide, was modified to increase oral toxicity to insects. One of the most active modified genes was then constitutively expressed in tobacco (Nicotiana tabacum) and transformants were evaluated for insect and disease resistance. Pathogenic...

  13. Growth and differentiation of prechondrogenic cells on bioactive self-assembled peptide nanofibers.

    PubMed

    Ustun, Seher; Tombuloglu, Aysegul; Kilinc, Murat; Guler, Mustafa O; Tekinay, Ayse B

    2013-01-14

    Restoration of cartilage defect remains a challenge, as the current treatments are ineffective to return tissue to its health. Thus, developing therapies for treatment of cartilage tissue damage caused by common joint diseases including osteoarthritis, rheumatoid arthritis, and accidents is crucial. Sulfated glycosaminoglycan molecules are vital constituents of both developing and mature cartilage extracellular matrix. The interplay between regulator proteins and glycosaminoglycan molecules has an essential role in coordinating differentiation, expansion, and patterning during cartilage development. In this study, we exploited the functional role of an extracellular matrix on chondrogenic differentiation by imitating extracellular matrix both chemically by imparting functional groups of native glycosaminoglycans and structurally through peptide nanofiber network. For this purpose, sulfonate, carboxylate, and hydroxyl groups were incorporated on self-assembled peptide nanofibers. We observed that when ATDC5 cells were cultured on functional peptide nanofibers, they rapidly aggregated in insulin-free medium and formed cartilage-like nodules and deposited sulfated glycosaminoglycans shown by Safranin-O staining. Moreover, collagen II and aggrecan gene expressions revealed by qRT-PCR were significantly enhanced, which indicated the remarkable bioactive role of this nanofiber system on chondrogenic differentiation. Overall, these results show that glycosaminoglycan mimetic peptide nanofiber system provides a promising platform for cartilage regeneration.

  14. Identification of a new androgen receptor (AR) co-regulator BUD31 and related peptides to suppress wild-type and mutated AR-mediated prostate cancer growth via peptide screening and X-ray structure analysis.

    PubMed

    Hsu, Cheng-Lung; Liu, Jai-Shin; Wu, Po-Long; Guan, Hong-Hsiang; Chen, Yuh-Ling; Lin, An-Chi; Ting, Huei-Ju; Pang, See-Tong; Yeh, Shauh-Der; Ma, Wen-Lung; Chen, Chung-Jung; Wu, Wen-Guey; Chang, Chawnshang

    2014-12-01

    Treatment with individual anti-androgens is associated with the development of hot-spot mutations in the androgen receptor (AR). Here, we found that anti-androgens-mt-ARs have similar binary structure to the 5α-dihydrotestosterone-wt-AR. Phage display revealed that these ARs bound to similar peptides, including BUD31, containing an Fxx(F/H/L/W/Y)Y motif cluster with Tyr in the +5 position. Structural analyses of the AR-LBD-BUD31 complex revealed formation of an extra hydrogen bond between the Tyr+5 residue of the peptide and the AR. Functional studies showed that BUD31-related peptides suppressed AR transactivation, interrupted AR N-C interaction, and suppressed AR-mediated cell growth. Combination of peptide screening and X-ray structure analysis may serve as a new strategy for developing anti-ARs that simultaneously suppress both wt and mutated AR function.

  15. USE OF MOLECULAR BIOLOGICAL TECHNIQUES TO EVALUATE EFFECT OF ENDOGENOUS HORMONES AND A XENOBIOTIC PESTICIDE ON GROWTH OF SHEEPSHEAD MINNOW

    EPA Science Inventory

    We have developed a teleost model to screen physiological effects of endocrine disrupting chemicals (EDCs) on somatic growth. Growth is largely controlled by the endocrine system via the growth-hormone releasing hormone (GRF) - growth hormone (GH) - insulin-like growth factor (IG...

  16. USE OF MOLECULAR BIOLOGICAL TECHNIQUES TO EVALUATE EFFECT OF ENDOGENOUS HORMONES AND A XENOBIOTIC PESTICIDE ON GROWTH OF SHEEPSHEAD MINNOW

    EPA Science Inventory

    We have developed a teleost model to screen physiological effects of endocrine disrupting chemicals (EDCs) on somatic growth. Growth is largely controlled by the endocrine system via the growth-hormone releasing hormone (GRF) - growth hormone (GH) - insulin-like growth factor (IG...

  17. Growth factor based therapies and intestinal disease: is glucagon-like peptide-2 the new way forward?

    PubMed

    Yazbeck, Roger; Howarth, Gordon S; Abbott, Catherine A

    2009-04-01

    Inflammatory bowel disease (IBD) is a chronic, debilitating disease associated with severe damage to the intestinal mucosa. Glucagon-like peptide-2 (GLP-2) is a potent and specific gastrointestinal growth factor that is demonstrating therapeutic potential for the prevention or treatment of an expanding number of intestinal diseases, including short bowel syndrome (SBS), small bowel enteritis and IBD. The biological activity of GLP-2 is limited due to proteolytic inactivation by the protease dipeptidyl peptidase (DP)IV. Inhibitors of DPIV activity may represent a novel strategy to prolong the growth promoting actions of GLP-2. This review outlines evidence for the clinical application of GLP-2, its degradation resistant analogue, Teduglutide, and novel DPIV inhibitors in efficacy studies utilizing pre-clinical models of intestinal damage, in particular IBD.

  18. Na/K-ATPase Mimetic pNaKtide Peptide Inhibits the Growth of Human Cancer Cells*

    PubMed Central

    Li, Zhichuan; Zhang, Zhongbing; Xie, Joe X.; Li, Xin; Tian, Jiang; Cai, Ting; Cui, Hongjuan; Ding, Hanfei; Shapiro, Joseph I.; Xie, Zijian

    2011-01-01

    Cells contain a large pool of nonpumping Na/K-ATPase that participates in signal transduction. Here, we show that the expression of α1 Na/K-ATPase is significantly reduced in human prostate carcinoma as well as in several human cancer cell lines. This down-regulation impairs the ability of Na/K-ATPase to regulate Src-related signaling processes. A supplement of pNaKtide, a peptide derived from α1 Na/K-ATPase, reduces the activities of Src and Src effectors. Consequently, these treatments stimulate apoptosis and inhibit growth in cultures of human cancer cells. Moreover, administration of pNaKtide inhibits angiogenesis and growth of tumor xenograft. Thus, the new findings demonstrate the in vivo effectiveness of pNaKtide and suggest that the defect in Na/K-ATPase-mediated signal transduction may be targeted for developing new anticancer therapeutics. PMID:21784855

  19. TGF-β1 activation in human hamstring cells through growth factor binding peptides on polycaprolactone surfaces.

    PubMed

    Crispim, J; Fernandes, H A M; Fu, S C; Lee, Y W; Jonkheijm, P; Saris, D B F

    2017-01-26

    The administration of soluble growth factors (GFs) to injured tendons and ligaments (T/L) is known to promote and enhance the healing process. However, the administration of GFs is a complex, expensive and heavily-regulated process and only achieved by employing supraphysiological GF concentrations. In addition, for proper healing, specific and spatial immobilization of the GFs (s) is critical. We hypothesized that biomaterials functionalized with GF-binding peptides can be employed to capture endogenous GFs in a spatially-controlled manner, thus overcoming the need for the exogenous administration of supraphysiological doses of GFs. Here we demonstrate that the modification of films of polycaprolactone (PCL) with transforming growth factor β1 (TGF-β1)-binding peptides allows GFs to be captured and presented to the target cells. Moreover, using a TGF-β reporter cell line and immunocytochemistry, we show that the GFs retained their biological activity. In human primary tendon cells, the immobilized TGF-β1 activated TGF-β target genes ultimately lead to a 2.5-fold increase in total collagen matrix production. In vivo implantation in rats clearly shows an accumulation of TGF-β1 on the polymer films functionalized with the TGF-β1-binding peptide when compared with the native films. This accumulation leads to an increase in the recruitment of inflammatory cells at day 3 and an increase in the fibrogenic response and vascularization around the implant at day 7. The results herein presented will endow current and future medical devices with novel biological properties and by doing so will accelerate T/L healing.

  20. Mutations in the Transmembrane Natriuretic Peptide Receptor NPR-B Impair Skeletal Growth and Cause Acromesomelic Dysplasia, Type Maroteaux

    PubMed Central

    Bartels, Cynthia F.; Bükülmez, Hülya; Padayatti, Pius; Rhee, David K.; van Ravenswaaij-Arts, Conny; Pauli, Richard M.; Mundlos, Stefan; Chitayat, David; Shih, Ling-Yu; Al-Gazali, Lihadh I.; Kant, Sarina; Cole, Trevor; Morton, Jenny; Cormier-Daire, Valérie; Faivre, Laurence; Lees, Melissa; Kirk, Jeremy; Mortier, Geert R.; Leroy, Jules; Zabel, Bernhard; Kim, Chong Ae; Crow, Yanick; Braverman, Nancy E.; van den Akker, Focco; Warman, Matthew L.

    2004-01-01

    The homodimeric transmembrane receptor natriuretic peptide receptor B (NPR-B [also known as guanylate cyclase B, GC-B, and GUC2B]; gene name NPR2) produces cytoplasmic cyclic GMP from GTP on binding its extracellular ligand, C-type natriuretic peptide (CNP). CNP has previously been implicated in the regulation of skeletal growth in transgenic and knockout mice. The autosomal recessive skeletal dysplasia known as “acromesomelic dysplasia, type Maroteaux” (AMDM) maps to an interval that contains NPR2. We sequenced DNA from 21 families affected by AMDM and found 4 nonsense mutations, 4 frameshift mutations, 2 splice-site mutations, and 11 missense mutations. Molecular modeling was used to examine the putative protein change brought about by each missense mutation. Three missense mutations were tested in a functional assay and were found to have markedly deficient guanylyl cyclase activity. We also found that obligate carriers of NPR2 mutations have heights that are below the mean for matched controls. We conclude that, although NPR-B is expressed in a number of tissues, its major role is in the regulation of skeletal growth. PMID:15146390

  1. A Randomised Comparison Evaluating Changes in Bone Mineral Density in Advanced Prostate Cancer: Luteinising Hormone-releasing Hormone Agonists Versus Transdermal Oestradiol

    PubMed Central

    Langley, Ruth E.; Kynaston, Howard G.; Alhasso, Abdulla A.; Duong, Trinh; Paez, Edgar M.; Jovic, Gordana; Scrase, Christopher D.; Robertson, Andrew; Cafferty, Fay; Welland, Andrew; Carpenter, Robin; Honeyfield, Lesley; Abel, Richard L.; Stone, Michael; Parmar, Mahesh K.B.; Abel, Paul D.

    2016-01-01

    Background Luteinising hormone-releasing hormone agonists (LHRHa), used as androgen deprivation therapy (ADT) in prostate cancer (PCa) management, reduce serum oestradiol as well as testosterone, causing bone mineral density (BMD) loss. Transdermal oestradiol is a potential alternative to LHRHa. Objective To compare BMD change in men receiving either LHRHa or oestradiol patches (OP). Design, setting, and participants Men with locally advanced or metastatic PCa participating in the randomised UK Prostate Adenocarcinoma TransCutaneous Hormones (PATCH) trial (allocation ratio of 1:2 for LHRHa:OP, 2006–2011; 1:1, thereafter) were recruited into a BMD study (2006–2012). Dual-energy x-ray absorptiometry scans were performed at baseline, 1 yr, and 2 yr. Interventions LHRHa as per local practice, OP (FemSeven 100 μg/24 h patches). Outcome measurements and statistical analysis The primary outcome was 1-yr change in lumbar spine (LS) BMD from baseline compared between randomised arms using analysis of covariance. Results and limitations A total of 74 eligible men (LHRHa 28, OP 46) participated from seven centres. Baseline clinical characteristics and 3-mo castration rates (testosterone ≤1.7 nmol/l, LHRHa 96% [26 of 27], OP 96% [43 of 45]) were similar between arms. Mean 1-yr change in LS BMD was −0.021 g/cm3 for patients randomised to the LHRHa arm (mean percentage change −1.4%) and +0.069 g/cm3 for the OP arm (+6.0%; p < 0.001). Similar patterns were seen in hip and total body measurements. The largest difference between arms was at 2 yr for those remaining on allocated treatment only: LS BMD mean percentage change LHRHa −3.0% and OP +7.9% (p < 0.001). Conclusions Transdermal oestradiol as a single agent produces castration levels of testosterone while mitigating BMD loss. These early data provide further supporting evidence for the ongoing phase 3 trial. Patient summary This study found that prostate cancer patients treated with transdermal oestradiol

  2. Ligand-biased regulation of PtdIns(3,4,5)P3-dependent signal transduction in GPCR control of pituitary hormone release.

    PubMed

    Pemberton, Joshua G; Chang, John P

    2016-12-01

    Biased signaling describes the selective activation of signal transduction cascades by structurally-related ligands downstream of shared G protein-coupled receptors (GPCRs). Although class I phosphoinositide 3-kinases (PI3Ks) are important components of GPCR-controlled transduction networks, little is known regarding the potential for biased regulation of class I PI3K-dependent signaling. The full compliment of class I PI3K catalytic subunits (p110α, p110β, p110δ and p110γ) first appear in bony fishes and, despite being associated with distinct cellular functions, all class I PI3Ks produce the lipid second-messenger phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3). We have previously shown that two endogenous gonadotropin-releasing hormones (GnRH2 and GnRH3), which both signal through shared Gαq/11-coupled receptors, selectively activate different subsets of class I PI3K isoforms in their control of hormone release from goldfish (Carassius auratus) pituitary cells. Here, we tested the hypothesis that the biased activation of class I PI3K isoforms results in the selective recruitment of PtdIns(3,4,5)P3-sensitive effectors downstream of GnRH-stabilized GPCRs using pharmacological mapping. Our results reveal that distinct PtdIns(3,4,5)P3-sensitive effectors are involved in the differential control of GnRH2- and GnRH3-stimulated, as well as basal, hormone release and implicate the participation of non-canonical PtdIns(3,4,5)P3-sensitive transduction elements. Furthermore, observations using a selective inhibitor of the shared Gβγ-effector interaction surface indicate a role for Gβγ-dependent signaling in the integrated control of pituitary hormone exocytosis. These novel findings add to our understanding of functional selectivity in GPCR signal transduction networks, in general, and reveal the complexity of biased signaling downstream of class I PI3K catalytic activity.

  3. Pathophysiological and diagnostic implications of cardiac biomarkers and antidiuretic hormone release in distinguishing immersion pulmonary edema from decompression sickness

    PubMed Central

    Louge, Pierre; Coulange, Mathieu; Beneton, Frederic; Gempp, Emmanuel; Le Pennetier, Olivier; Algoud, Maxime; Dubourg, Lorene; Naibo, Pierre; Marlinge, Marion; Michelet, Pierre; Vairo, Donato; Kipson, Nathalie; Kerbaul, François; Jammes, Yves; Jones, Ian M.; Steinberg, Jean-Guillaume; Ruf, Jean; Guieu, Régis; Boussuges, Alain; Fenouillet, Emmanuel

    2016-01-01

    Abstract Immersion pulmonary edema (IPE) is a misdiagnosed environmental illness caused by water immersion, cold, and exertion. IPE occurs typically during SCUBA diving, snorkeling, and swimming. IPE is sometimes associated with myocardial injury and/or loss of consciousness in water, which may be fatal. IPE is thought to involve hemodynamic and cardiovascular disturbances, but its pathophysiology remains largely unclear, which makes IPE prevention difficult. This observational study aimed to document IPE pathogenesis and improve diagnostic reliability, including distinguishing in some conditions IPE from decompression sickness (DCS), another diving-related disorder. Thirty-one patients (19 IPE, 12 DCS) treated at the Hyperbaric Medicine Department (Ste-Anne hospital, Toulon, France; July 2013–June 2014) were recruited into the study. Ten healthy divers were recruited as controls. We tested: (i) copeptin, a surrogate marker for antidiuretic hormone and a stress marker; (ii) ischemia-modified albumin, an ischemia/hypoxia marker; (iii) brain-natriuretic peptide (BNP), a marker of heart failure, and (iv) ultrasensitive-cardiac troponin-I (cTnI), a marker of myocardial ischemia. We found that copeptin and cardiac biomarkers were higher in IPE versus DCS and controls: (i) copeptin: 68% of IPE patients had a high level versus 25% of DCS patients (P < 0.05) (mean ± standard-deviation: IPE: 53 ± 61 pmol/L; DCS: 15 ± 17; controls: 6 ± 3; IPE versus DCS or controls: P < 0.05); (ii) ischemia-modified albumin: 68% of IPE patients had a high level versus 16% of DCS patients (P < 0.05) (IPE: 123 ± 25 arbitrary-units; DCS: 84 ± 25; controls: 94 ± 7; IPE versus DCS or controls: P < 0.05); (iii) BNP: 53% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 383 ± 394 ng/L; DCS: 37 ± 28; controls: 19 ± 15; IPE versus DCS or controls: P < 0.01); (iv) cTnI: 63% of IPE

  4. Pathophysiological and diagnostic implications of cardiac biomarkers and antidiuretic hormone release in distinguishing immersion pulmonary edema from decompression sickness.

    PubMed

    Louge, Pierre; Coulange, Mathieu; Beneton, Frederic; Gempp, Emmanuel; Le Pennetier, Olivier; Algoud, Maxime; Dubourg, Lorene; Naibo, Pierre; Marlinge, Marion; Michelet, Pierre; Vairo, Donato; Kipson, Nathalie; Kerbaul, François; Jammes, Yves; Jones, Ian M; Steinberg, Jean-Guillaume; Ruf, Jean; Guieu, Régis; Boussuges, Alain; Fenouillet, Emmanuel

    2016-06-01

    Immersion pulmonary edema (IPE) is a misdiagnosed environmental illness caused by water immersion, cold, and exertion. IPE occurs typically during SCUBA diving, snorkeling, and swimming. IPE is sometimes associated with myocardial injury and/or loss of consciousness in water, which may be fatal. IPE is thought to involve hemodynamic and cardiovascular disturbances, but its pathophysiology remains largely unclear, which makes IPE prevention difficult. This observational study aimed to document IPE pathogenesis and improve diagnostic reliability, including distinguishing in some conditions IPE from decompression sickness (DCS), another diving-related disorder.Thirty-one patients (19 IPE, 12 DCS) treated at the Hyperbaric Medicine Department (Ste-Anne hospital, Toulon, France; July 2013-June 2014) were recruited into the study. Ten healthy divers were recruited as controls. We tested: (i) copeptin, a surrogate marker for antidiuretic hormone and a stress marker; (ii) ischemia-modified albumin, an ischemia/hypoxia marker; (iii) brain-natriuretic peptide (BNP), a marker of heart failure, and (iv) ultrasensitive-cardiac troponin-I (cTnI), a marker of myocardial ischemia.We found that copeptin and cardiac biomarkers were higher in IPE versus DCS and controls: (i) copeptin: 68% of IPE patients had a high level versus 25% of DCS patients (P < 0.05) (mean ± standard-deviation: IPE: 53 ± 61 pmol/L; DCS: 15 ± 17; controls: 6 ± 3; IPE versus DCS or controls: P < 0.05); (ii) ischemia-modified albumin: 68% of IPE patients had a high level versus 16% of DCS patients (P < 0.05) (IPE: 123 ± 25 arbitrary-units; DCS: 84 ± 25; controls: 94 ± 7; IPE versus DCS or controls: P < 0.05); (iii) BNP: 53% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 383 ± 394 ng/L; DCS: 37 ± 28; controls: 19 ± 15; IPE versus DCS or controls: P < 0.01); (iv) cTnI: 63% of IPE patients had a high

  5. IGF-1R peptide vaccines/mimics inhibit the growth of BxPC3 and JIMT-1 cancer cells and exhibit synergistic antitumor effects with HER-1 and HER-2 peptides.

    PubMed

    Foy, Kevin Chu; Miller, Megan J; Overholser, Jay; Donnelly, Siobhan M; Nahta, Rita; Kaumaya, Pravin Tp

    2014-11-01

    The insulin-like growth factor-1 receptor (IGF-1R) plays a crucial role in cellular growth, proliferation, transformation, and inhibition of apoptosis. A myriad of human cancer types have been shown to overexpress IGF-1R, including breast and pancreatic adenocarcinoma. IGF-1R signaling interferes with numerous receptor pathways, rendering tumor cells resistant to chemotherapy, anti-hormonal therapy, and epidermal growth factor receptor (EGFR, also known as HER-1) and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2, (ERBB2, best known as HER-2) -targeted therapies. Targeting the IGF:IGF-1R axis with innovative peptide inhibitors and vaccine antibodies thus represents a promising therapeutic strategy to overcome drug resistance and to provide new avenues for individualized and combinatorial treatment strategies. In this study, we designed, synthesized, and characterized several B-cell epitopes from the IGF-1:IGF-1R axis. The chimeric peptide epitopes were highly immunogenic in outbred rabbits, eliciting high levels of peptide vaccine antibodies. The IGF-1R peptide antibodies and peptide mimics inhibited cell proliferation and receptor phosphorylation, induced apoptosis and antibody-dependent cellular cytotoxicity (ADCC), and significantly inhibited tumor growth in the transplantable BxPC-3 pancreatic and JIMT-1 breast cancer models. Our results showed that the peptides and antibodies targeting residues 56-81 and 233-251 are potential therapeutic and vaccine candidates for the treatment of IGF-1R-expressing cancers, including those that are resistant to the HER-2-targeted antibody, trastuzumab. Additionally, we found additive antitumor effects for the combination treatment of the IGF-1R 56-81 epitope with HER-1-418 and HER-2-597 epitopes. Treatment with the IGF-1R/HER-1 or IGF-1R/HER-2 combination inhibited proliferation, invasion, and receptor phosphorylation, and induced apoptosis and ADCC, to a greater degree than single agents.

  6. Intestinal growth in parenterally-fed rats induced by the combined effects of glucagon-like peptide 2 and epidermal growth factor.

    PubMed

    Kitchen, Paul A; Goodlad, Robert A; FitzGerald, Anthony J; Mandir, Nikki; Ghatei, Mohammed A; Bloom, Stephen R; Berlanga-Acosta, Jorge; Playford, Raymond J; Forbes, Alastair; Walters, Julian R F

    2005-01-01

    Parenteral nutrition and the absence of luminal feeding result in impaired intestinal growth and differentiation of enterocytes. Glucagon-like peptide 2 (GLP-2) and epidermal growth factor (EGF) have each been shown to have trophic effects on the intestine, and thus have the potential to benefit patients fed parenterally, such as those with intestinal failure from short bowel syndrome. We report studies aimed to determine whether there may be synergistic effects of these 2 peptides. Rats were established on parenteral nutrition (PN) and infused for 6 days with GLP-2 (20 microg/d), EGF (20 microg/d), or GLP-2 + EGF (20 microg/d of each). These groups were compared with untreated PN-fed and orally-fed controls. Tissue was obtained from small intestine and colon to determine growth, proliferation, and representative gene expression. Small intestinal weight was increased by 75%, 43%, and 116% in the GLP-2, EGF, and GLP-2 + EGF groups, respectively, compared with PN controls (all p < .001). Cell proliferation increased with GLP-2, EGF, and GLP-2 + EGF in proximal small intestine by factors of 2.3, 1.7, and 3.4 respectively (p < .001). A synergistic effect on villous and crypt area was observed in the proximal small intestine when GLP-2 and EGF were combined (p < .05). GLP-2 had no effect in the colon, unlike EGF. Further studies showed GLP-2 + EGF significantly increased expression in distal small intestine of transcripts for the bile acid transport protein IBABP (p < .05) and showed a significant correlation between the expression of IBABP and the transcription factor HNF-4. Both GLP-2 and EGF upregulate growth of the small intestine, and this is augmented when GLP-2 and EGF are combined. These findings may lead to improved treatment of patients receiving PN.

  7. Anti-synthetic peptide antibody reacting at the fusion junction of deletion-mutant epidermal growth factor receptors in human glioblastoma

    SciTech Connect

    Humphrey, P.A.; Zalutsky, M.R.; Fuller, G.N.; Archer, G.E.; Friedman, H.S.; Kwatra, M.M.; Bigner, S.H.; Bigner, D.D. ); Wong, A.J. ); Vogelstein, B. )

    1990-06-01

    The authors have investigated human gliomas that amplify and rearrange the epidermal growth factor receptor gene, with generation of an in-frame deletion mutation of 802 nucleotides in the external domain. This in-frame deletion mutation generates a local amino acid sequence at the fusion junction of what normally were distant polypeptide sequences in the intact epidermal growth factor receptor. This 14-amino acid peptide was chemically synthesized, coupled to keyhole limpet hemocyanin, and used as an immunogen in rabbits. The elicited antibody reacted specifically with the fusion peptide in ELISA. The anti-fusion junction peptide antibody was purified by passage of the antiserum over a peptide affinity column with acidic elution. The purified antibody selectively bound the glioma deletion mutant as compared to the intact epidermal growth factor receptor as assessed by immunocytochemistry, immunofluorescence, immunoprecipitation with gel electrophoresis, and binding experiments using radioiodinated antibody. These data indicate that it is feasible to generate site-specific anti-peptide antibodies that are highly selective for mutant proteins in human tumors. The anti-peptide antibody described here, and other mutation site-specific antibodies, should be ideal candidates for tumor immunoimaging and immunotherapy.

  8. The Influence of Peptide Modifications of Bioactive Glass on Human Mesenchymal Stem Cell Growth and Function

    NASA Astrophysics Data System (ADS)

    Ammar, Mohamed

    2011-12-01

    Bioactive glass is known for its potential as a bone scaffold due to its ability to stimulate osteogenesis and induce bone formation. Broadening this potential to include the differentiation of human mesenchymal stem cells (hMSCs) to bone cells will enhance the healing process in bone defects. The surface of bioactive glass made by the sol-gel technique with the composition of 70% SiO2-30% CaO (mol %) was grafted with 3 peptides sequences in different combinations from proteins (fibronectin BMP-2 and BMP-9) that are known to promote the adhesion, differentiation and osteogenesis process. The experiment was done in two forms, a 2D non-porous thin film and a 3D nano-macroporous structure. hMSCs were grown on the materials for a total of five weeks. The 2D materials were tested for the expression of 3 osteogenic markers (osteopontin, osteocalcin and osteonectin) through immunocytochemistry. The 3D forms were monitored for cell's adhesion, morphology, spreading and proliferation by scanning electron microscopy, in addition to proliferation assay and alkaline phosphatase activity measurement. Results showed that hMSCs poorly adhered to the 2D thin films, but the few cells survived showed enhanced expression of the osteogenic markers. On the 3D form, cells showed enhanced proliferation at week one and more survival of the cells on the materials grafted with the adhesion peptide for the successive weeks in comparison to the positive control samples. Enhanced alkaline phosphatase activity was also detected compared to the negative control samples but were still below the positive control samples. In conclusion, the peptide grafting could increase the effect of bioactive glass but more peptide combinations should be examined to improve the effects on the differentiation and osteogenic activity of the hMSCs.

  9. Regulation of Breast Carcinoma Growth and Neovascularization by Novel Peptide Sequences in Thrombospondin

    DTIC Science & Technology

    1998-09-01

    B., Mulliken, J. B., and Folkman, J. Interferon alfa -2a therapy for life-threatening hemangiomas of infancy, N. Engl. J. Med. 326: 1456-1463, 1992. 8...angiogenic factors have also been identified, including thrombospondin (5, 6), interferon - alpha (7), platelet factor 4 (8), SPARC (9...inhibited by 60% for MDA-MB-435 cells with a 90% reduction in 31SO 4 incorporation (Fig. 2B ). RGD 8 peptides did not inhibit adhesion of MDA-MB-435 cells on

  10. Optimization of adiponectin-derived peptides for inhibition of cancer cell growth and signaling.

    PubMed

    Otvos, Laszlo; Kovalszky, Ilona; Olah, Julia; Coroniti, Roberta; Knappe, Daniel; Nollmann, Friederike I; Hoffmann, Ralf; Wade, John D; Lovas, Sandor; Surmacz, Eva

    2015-05-01

    Adiponectin, an adipose tissue-excreted adipokine plays protective roles in metabolic and cardiovascular diseases and exerts anti-cancer activities, partially by interfering with leptin-induced signaling. Previously we identified the active site in the adiponectin protein, and generated both a nanomolar monomeric agonist of the adiponectin receptor (10-mer ADP355) and an antagonist (8-mer ADP400) to modulate various adiponectin receptor-mediated cellular functions. As physiologically circulating adiponectin forms multimeric complexes, we also generated an agonist dimer with improved biodistribution and in vitro efficacy. In the current report, we attempted to optimize the monomeric agonist structure. Neither extension of the peptide up to 14-mer analogs nor reinstallation of native residues in permissible positions enhanced significantly the activity profile. The only substitutions that resulted in 5-10-fold improved agonistic activity were the replacement of turn-forming Gly4 and Tyr7 residues with Pro and Hyp, respectively, yielding the more active native β-sheet structure. All peptides retained good stability in human serum exhibiting half-lives >2 h. The cellular efficacy and stability rankings among the peptides followed expected structure-activity relationship trends. To investigate whether simultaneous activation of adiponectin pathways and inhibition of leptin-induced signals can result in cytostatic and anti-oncogenic signal transduction processes, we developed a chimera of the leptin receptor antagonist peptide Allo-aca (placed to the N-terminus) and ADP355 (at the C-terminus). The in vitro anti-tumor activity and intracellular signaling of the chimera were dominated by the more active Allo-aca component. The ADP355 part, however, reversed unfavorable in vivo metabolic effects of the leptin receptor antagonist.

  11. The Antitumor Peptide CIGB-552 Increases COMMD1 and Inhibits Growth of Human Lung Cancer Cells.

    PubMed

    Fernández Massó, Julio R; Oliva Argüelles, Brizaida; Tejeda, Yelaine; Astrada, Soledad; Garay, Hilda; Reyes, Osvaldo; Delgado-Roche, Livan; Bollati-Fogolín, Mariela; Vallespí, Maribel G

    2013-01-01

    We have demonstrated that the peptide L-2 designed from an alanine scanning of the Limulus-derived LALF32-51 region is a potential candidate for the anticancer therapy and its cell-penetrating capacity is an associated useful property. By the modification in the primary structure of L-2, a second-generation peptide (CIGB-552) was developed. However, the molecular mechanism underlying its cytotoxic activity remains partially unknown. In this study, it was shown that CIGB-552 increases the levels of COMMD1, a protein involved in copper homeostasis, sodium transport, and the NF-κB signaling pathway. We found that CIGB-552 induces ubiquitination of RelA and inhibits the antiapoptotic activity regulated by NF-κB, whereas the knockdown of COMMD1 blocks this effect. We also found that CIGB-552 decreases the antioxidant capacity and induces the peroxidation of proteins and lipids in the tumor cells. Altogether, this study provides new insights into the mechanism of action of the peptide CIGB-552, which could be relevant in the design of future anticancer therapies.

  12. The Antitumor Peptide CIGB-552 Increases COMMD1 and Inhibits Growth of Human Lung Cancer Cells

    PubMed Central

    Fernández Massó, Julio R.; Oliva Argüelles, Brizaida; Tejeda, Yelaine; Astrada, Soledad; Garay, Hilda; Reyes, Osvaldo; Delgado-Roche, Livan; Bollati-Fogolín, Mariela; Vallespí, Maribel G.

    2013-01-01

    We have demonstrated that the peptide L-2 designed from an alanine scanning of the Limulus-derived LALF32-51 region is a potential candidate for the anticancer therapy and its cell-penetrating capacity is an associated useful property. By the modification in the primary structure of L-2, a second-generation peptide (CIGB-552) was developed. However, the molecular mechanism underlying its cytotoxic activity remains partially unknown. In this study, it was shown that CIGB-552 increases the levels of COMMD1, a protein involved in copper homeostasis, sodium transport, and the NF-κB signaling pathway. We found that CIGB-552 induces ubiquitination of RelA and inhibits the antiapoptotic activity regulated by NF-κB, whereas the knockdown of COMMD1 blocks this effect. We also found that CIGB-552 decreases the antioxidant capacity and induces the peroxidation of proteins and lipids in the tumor cells. Altogether, this study provides new insights into the mechanism of action of the peptide CIGB-552, which could be relevant in the design of future anticancer therapies. PMID:23401744

  13. Effects of maternal plasmid GHRH treatment on offspring growth

    USDA-ARS?s Scientific Manuscript database

    To differentiate prenatal effects of plasmid growth hormone-releasing hormone (GHRH) treatment from maternal effects mediated by lactation on long-term growth of offspring, a cross-fostering study was designed. Pregnant sows (n = 12) were untreated (n = 6), or received either a Wt-GHRH (n = 2), or H...

  14. Brainstem projections to the medial preoptic region containing the luteinizing hormone-releasing hormone perikarya in the rat. An immunohistochemical and retrograde transport study.

    PubMed

    Castañeyra-Perdomo, A; Pérez-Delgado, M M; Montagnese, C; Coen, C W

    1992-05-11

    The afferent projections to the anterior medial preoptic area (MPA) from the brainstem have been studied, in female Wistar rats, by retrograde tracing with horseradish peroxidase (HRP). The HRP was injected by iontophoresis into the preoptic region containing the luteinizing hormone-releasing hormone (LHRH) perikarya. The brain sections including the MPA were reacted with diaminobenzidine (DAB) to reveal the injection site; the LHRH cells were then immunohistochemically identified using DAB with ammonium nickel sulphate. When the injection site incorporated the LHRH cells, the brainstem sections were reacted with the DAB nickel solution to detect lysosomal HRP and then immunohistochemically processed to locate the adrenaline-synthesizing cells using DAB alone. The results confirm the brainstem projections to the MPA from the central grey matter, ventral tegmental area, subcoeruleus area, the dorsal raphe nucleus, the lateral parabrachial nucleus, the raphe pontis nucleus, the raphe obscurus nucleus, the region of the paragigantocellular nucleus and the nucleus of the solitary tract. Given the considerable evidence implicating the ascending adrenergic systems in the regulation of LHRH, we focused our attention on the afferents from the locus coeruleus, area postrema and the adrenaline-synthesizing cell groups (C1-3). The only cells which were retrogradely labelled and immunopositive for phenylethanolamine N-methyltransferase were found in C3.

  15. Effects of ionizing radiation and pretreatment with (D-Leu6,des-Gly10) luteinizing hormone-releasing hormone ethylamide on developing rat ovarian follicles

    SciTech Connect

    Jarrell, J.; YoungLai, E.V.; McMahon, A.; Barr, R.; O'Connell, G.; Belbeck, L.

    1987-10-01

    To assess the effects of a gonadotropin-releasing hormone agonist, (D-Leu6,des-Gly10) luteinizing hormone-releasing hormone ethylamide, in ameliorating the damage caused by ionizing radiation, gonadotropin-releasing hormone agonist was administered to rats from day 22 to 37 of age in doses of 0.1, 0.4, and 1.0 microgram/day or vehicle and the rats were sacrificed on day 44 of age. There were no effects on estradiol, progesterone, luteinizing, or follicle-stimulating hormone, nor an effect on ovarian follicle numbers or development. In separate experiments, rats treated with gonadotropin-releasing hormone agonist in doses of 0.04, 0.1, 0.4, or 1.0 microgram/day were either irradiated or sham irradiated on day 30 and all groups sacrificed on day 44 of age. Irradiation produced a reduction in ovarian weight and an increase in ovarian follicular atresia. Pretreatment with the agonist prevented the reduction in ovarian weight and numbers of primordial and preantral follicles but not healthy or atretic antral follicles. Such putative radioprotection should be tested on actual reproductive performance.

  16. Aromatase inhibitors with or without luteinizing hormone-releasing hormone agonist for metastatic male breast cancer: report of four cases and review of the literature.

    PubMed

    Kuba, Sayaka; Ishida, Mayumi; Oikawa, Masahiro; Nakamura, Yoshiaki; Yamanouchi, Kosho; Tokunaga, Eriko; Taguchi, Kenichi; Esaki, Taito; Eguchi, Susumu; Ohno, Shinji

    2016-11-01

    The roles of aromatase inhibitors (AIs) and luteinizing hormone-releasing hormone (LH-RH) agonists in the management of male breast cancer remain uncertain, with no reports in Japanese men. We report four Japanese male patients with metastatic breast cancer treated with AIs with or without an LH-RH agonist, and consider the relationship between treatment effect and estradiol (E2) concentration. Three patients were initially treated with AI alone after selective estrogen receptor modulators (SERMs), and one received AIs plus an LH-RH agonist after a SERM. Two patients treated with an AI alone responded, one patient with E2 levels below the lower assay limit and the other with levels above the limit. The other treated with an AI alone experienced progression regardless of the E2 levels below the lower assay limit, however, responded after the addition of an LH-RH agonist. E2 concentrations were related to the efficacy of treatment in one patient. The patient initially treated with an AI plus an LH-RH agonist also responded. No grade 3 or 4 adverse events were observed in any of the patients treated with AIs with or without an LH-RH agonist. AIs with or without an LH-RH agonist offer an effective treatment option for hormone receptor-positive metastatic male breast cancer.

  17. Luteinizing hormone-releasing hormone targeted poly(methyl vinyl ether maleic acid) nanoparticles for doxorubicin delivery to MCF-7 breast cancer cells.

    PubMed

    Varshosaz, Jaleh; Jahanian-Najafabadi, Ali; Ghazzavi, Jila

    2016-08-01

    The purpose of this study was to design a targeted anti-cancer drug delivery system for breast cancer. Therefore, doxorubicin (DOX) loaded poly(methyl vinyl ether maleic acid) nanoparticles (NPs) were prepared by ionic cross-linking method using Zn(2+) ions. To optimise the effect of DOX/polymer ratio, Zn/polymer ratio, and stirrer rate a full factorial design was used and their effects on particle size, zeta potential, loading efficiency (LE, %), and release efficiency in 72 h (RE72, %) were studied. Targeted NPs were prepared by chemical coating of tiptorelin/polyallylamin conjugate on the surface of NPs by using 1-ethyl-3-(3-dimethylaminopropyl) carboiimid HCl as cross-linking agent. Conjugation efficiency was measured by Bradford assay. Conjugated triptorelin and targeted NPs were studied by Fourier-transform infrared spectroscopy (FTIR). The cytotoxicity of DOX loaded in targeted NPs and non-targeted ones were studied on MCF-7 cells which overexpress luteinizing hormone-releasing hormone (LHRH) receptors and SKOV3 cells as negative LHRH receptors using Thiazolyl blue tetrazolium bromide assay. The best results obtained from NPs prepared by DOX/polymer ratio of 5%, Zn/polymer ratio of 50%, and stirrer rate of 960 rpm. FTIR spectrum confirmed successful conjugation of triptorelin to NPs. The conjugation efficiency was about 70%. The targeted NPs showed significantly less IC50 for MCF-7 cells compared to free DOX and non-targeted NPs.

  18. Influence of gonadotropic hormone-releasing hormone analog (GnRH-A) on plasma sex steroid profiles and milt production in male winter flounder, Pseudopleuronectes americanus (Walbaum).

    PubMed

    Harmin, S A; Crim, L W

    1993-03-01

    The effects of gonadotropic hormone-releasing hormone analog (GnRH-A) treatment on the onset and duration of increases in plasma sex steroids and milt production (milt volume and number of spermatozoa) were investigated in prespawning male winter flounder. After treatment of maturing males during the winter with a single injection of either 20 or 200 μg/kg [D-Ala(6), Pro(9)-NHEt]LHRH (GnRH-A), plasma levels of testosterone and 11-ketotestosterone were increased within 12h and the steroid hormone levels remained elevated for long periods lasting several days. The androgenic steroid response of males was delayed after the administration of a lower dose of GnRH-A (2 μg/kg). Although a single GnRH-A injection in December or January advanced the onset of spermiation in some males, only small amounts (<50 μl) of milt could be collected. By March, all males were in spermiating condition following GnRH-A treatment; however, significant increases in sperm production, particularly increases in milt volume, occurred in fish twice treated with GnRH-A.

  19. Luteininzing hormone releasing hormones analogs in combination with tamoxifen for the adjuvant treatment of premenopausal women with hormone receptor positive breast cancer.

    PubMed

    Conte, Benedetta; Poggio, Francesca; Del Mastro, Lucia

    2017-09-01

    The role of ovarian function suppression (OFS) through luteinizing hormone-releasing hormone agonists (LHRHa) in addition to tamoxifen has been questioned until recently. In 2015, two large clinical trials led to a paradigm shift in the adjuvant endocrine treatment of premenopausal women, introducing the use of LHRHa plus tamoxifen (or aromatase inhibitor, AI) into current clinical practice. Areas covered: The present review aims to provide an in-depth overview of the role of LHRHa+tamoxifen for the adjuvant treatment of premenopausal women with hormone receptor positive breast cancer (HR+BC). Expert opinion: The addition of LHRHa to endocrine treatment (either tamoxifen or AI) is effective in premenopausal women who are at high risk of relapse. To date, no clear recommendations are available for the choice between LHRHa+tamoxifen and LHRH+AI. Although recent data showed better DFS with LHRHa+AI, other issues should be considered: 1) approximately 20 out of 100 women do not reach complete OFS with LHRHa+AI; 2) there is no extended endocrine therapy option that can be applied to women who received 5 years of LHRHa+AI and remained premenopausal at the end of the fifth year. Long-term results of the SOFT-TEXT study are needed to establish if LHRHa+AI is superior to LHRHa+tamoxifen.

  20. The Association between Newborn Regional Body Composition and Cord Blood Concentrations of C-Peptide and Insulin-Like Growth Factor I.

    PubMed

    Carlsen, Emma M; Renault, Kristina M; Jensen, Rikke B; Nørgaard, Kirsten; Jensen, Jens-Erik B; Nilas, Lisbeth; Cortes, Dina; Michaelsen, Kim F; Pryds, Ole

    2015-01-01

    Third trimester fetal growth is partially regulated by C-peptide and insulin-like growth factor I (IGF-I). Prenatal exposures including maternal obesity and high gestational weight gain as well as high birth weight have been linked to subsequent metabolic disease. We evaluated the associations between newborn regional body composition and cord blood levels of C-peptide and IGF-I. We prospectively included obese and normal-weight mothers and their newborns; cord blood was collected and frozen. Analyses of C-peptide and IGF-I were performed simultaneously, after recruitment was completed. Newborn regional body composition was assessed with dual-energy X-ray absorptiometry scanning (DXA) within 48 hours of birth. Three hundred thirty-six term infants were eligible to participate in the study; of whom 174 (52%) infants had cord blood taken. Total, abdominal and arm and leg fat mass were positively associated with C-peptide (p < 0.001). Arm and leg fat mass was associated with IGF-I concentration: 28 g [95% confidence interval: 4, 53] per doubling of IGF-I. There was no association between total or abdominal fat mass and IGF-I. Fat-free mass was positively associated with both C-peptide (p < 0.001) and IGF-I (p = 0.004). Peripheral fat tissue accumulation was associated with cord blood C-peptide and IGF-I. Total and abdominal fat masses were related to C-peptide but not to IGF-I. Thus, newborn adiposity is partially mediated through C-peptide and early linear growth is associated with IGF-I.

  1. Zfp521 Is a Target Gene and Key Effector of Parathyroid Hormone-Related Peptide Signaling in Growth Plate Chondrocytes

    PubMed Central

    Correa, Diego; Hesse, Eric; Seriwatanachai, Dutmanee; Kiviranta, Riku; Saito, Hiroaki; Yamana, Kei; Neff, Lynn; Atfi, Azeddine; Coillard, Lucie; Sitara, Despina; Maeda, Yukiko; Warming, Soren; Jenkins, Nancy A.; Copeland, Neal G.; Horne, William C.; Lanske, Beate; Baron, Roland

    2010-01-01

    Summary In the growth plate, the interplay between Parathyroid Hormone-Related Peptide (PTHrP) and Indian Hedgehog (Ihh) signaling tightly regulates chondrocyte proliferation and differentiation during longitudinal bone growth. We found that PTHrP increases the expression of Zfp521, a zinc finger transcriptional co-regulator, in pre-hypertrophic chondrocytes. Mice with chondrocyte-targeted deletion of Zfp521 resembled PTHrP-/- and chondrocyte-specific PTHR1-/- mice, with decreased chondrocyte proliferation, early hypertrophic transition and reduced growth plate thickness. Deleting Zfp521 increased expression of Runx2 and Runx2 target genes, and decreased cyclin D1 and Bcl-2 expression while increasing caspase-3 activation and apoptosis. Zfp521 associated with Runx2 in chondrocytes, antagonizing its activity via an HDAC4-dependent mechanism. PTHrP failed to up-regulate cyclin D1 and to antagonize Runx2, Ihh and Collagen X expression when Zfp521 was absent. Thus, Zfp521 is an important PTHrP target gene that regulates growth plate chondrocyte proliferation and differentiation. PMID:20951345

  2. Pituitary adenylate cyclase activating peptide (PACAP) immunoreactivity and mRNA expression in the duck gastrointestinal tract.

    PubMed

    Mirabella, N; Squillacioti, C; Colitti, M; Germano, G; Pelagalli, A; Paino, G

    2002-06-01

    The presence and distribution of pituitary adenylate cyclase activating peptide (PACAP) immunoreactivity were studied in the duck gastrointestinal tract using immunohistochemistry and radioimmunoassays. Expression and distribution of PACAP mRNA were also studied using reverse transcriptase polymerase chain reaction (RT-PCR) and hybridization techniques. In addition, a partial coding sequence (cds) of the duck growth hormone-releasing hormone (GRF)/PACAP gene was identified. The presence of both PACAP-38 and PACAP-27 was demonstrated, the former being the predominant form. PACAP immunoreactivity was found in neurons and fibers of the enteric nervous system (ENS), in endocrine cells and in the gut associated lymphoid tissue (GALT). Double immunostaining showed that PACAP is almost completely colocalized with vasoactive intestinal peptide (VIP) in the ENS. Moreover, PACAP was also found in nitric oxide synthase (NOS)-containing neurons and nerve fibers. Radioimmunoassay (RIA) performed on denervated gut showed that more than one-half of the duodenal PACAP is extrinsic in origin. RT-PCR, Northern blot analysis and in situ hybridization confirmed the immunohistochemical data. The findings of the present study suggest that, in birds, PACAP may have multiple roles in regulating gastrointestinal functions.

  3. Alternative splicing of pre-mRNA in cancer: focus on G protein-coupled peptide hormone receptors.

    PubMed

    Körner, Meike; Miller, Laurence J

    2009-08-01

    Through alternative splicing, multiple different transcripts can be generated from a single gene. Alternative splicing represents an important molecular mechanism of gene regulation in physiological processes such as developmental programming as well as in disease. In cancer, splicing is significantly altered. Tumors express a different collection of alternative spliceoforms than normal tissues. Many tumor-associated splice variants arise from genes with an established role in carcinogenesis or tumor progression, and their functions can be oncogenic. This raises the possibility that products of alternative splicing play a pathogenic role in cancer. Moreover, cancer-associated spliceoforms represent potential diagnostic biomarkers and therapeutic targets. G protein-coupled peptide hormone receptors provide a good illustration of alternative splicing in cancer. The wild-type forms of these receptors have long been known to be expressed in cancer and to modulate tumor cell functions. They are also recognized as attractive clinical targets. Recently, splice variants of these receptors have been increasingly identified in various types of cancer. In particular, alternative cholecystokinin type 2, secretin, and growth hormone-releasing hormone receptor spliceoforms are expressed in tumors. Peptide hormone receptor splice variants can fundamentally differ from their wild-type receptor counterparts in pharmacological and functional characteristics, in their distribution in normal and malignant tissues, and in their potential use for clinical applications.

  4. Regulatory Peptides i