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Sample records for hepatic drug-metabolizing enzymes

  1. Gene Expression Variability in Human Hepatic Drug Metabolizing Enzymes and Transporters

    PubMed Central

    Yang, Lun; Price, Elvin T.; Chang, Ching-Wei; Li, Yan; Huang, Ying; Guo, Li-Wu; Guo, Yongli; Kaput, Jim; Shi, Leming; Ning, Baitang

    2013-01-01

    Interindividual variability in the expression of drug-metabolizing enzymes and transporters (DMETs) in human liver may contribute to interindividual differences in drug efficacy and adverse reactions. Published studies that analyzed variability in the expression of DMET genes were limited by sample sizes and the number of genes profiled. We systematically analyzed the expression of 374 DMETs from a microarray data set consisting of gene expression profiles derived from 427 human liver samples. The standard deviation of interindividual expression for DMET genes was much higher than that for non-DMET genes. The 20 DMET genes with the largest variability in the expression provided examples of the interindividual variation. Gene expression data were also analyzed using network analysis methods, which delineates the similarities of biological functionalities and regulation mechanisms for these highly variable DMET genes. Expression variability of human hepatic DMET genes may affect drug-gene interactions and disease susceptibility, with concomitant clinical implications. PMID:23637747

  2. Effects of naturally occurring coumarins on hepatic drug-metabolizing enzymes inmice

    SciTech Connect

    Kleiner, Heather E. Xia, Xiaojun; Sonoda, Junichiro; Zhang, Jun; Pontius, Elizabeth; Abey, Jane; Evans, Ronald M.; Moore, David D.; DiGiovanni, John

    2008-10-15

    Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was to compare a broader range of naturally occurring coumarins (simple coumarins, and furanocoumarins of the linear and angular type) for their abilities to modulate hepatic drug-metabolizing enzymes when administered orally to mice. We now report that all of the different coumarins tested (coumarin, limettin, auraptene, angelicin, bergamottin, imperatorin and isopimpinellin) induced hepatic GST activities, whereas the linear furanocoumarins possessed the greatest abilities to induce hepatic P450 activities, in particular P450 2B and 3A. In both cases, this corresponded to an increase in protein expression of the enzymes. Induction of P4502B10, 3A11, and 2C9 by xenobiotics often is a result of activation of the pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Using a pregnane X receptor reporter system, our results demonstrated that isopimpinellin activated both PXR and its human ortholog SXR by recruiting coactivator SRC-1 in transfected cells. In CAR transfection assays, isopimpinellin counteracted the inhibitory effect of androstanol on full-length mCAR, a Gal4-mCAR ligand-binding domain fusion, and restored coactivator binding. Orally administered isopimpinellin induced hepatic mRNA expression of Cyp2b10, Cyp3a11, and GSTa in CAR(+/+) wild-type mice. In contrast, the induction of Cyp2b10 mRNA by isopimpinellin was attenuated in the CAR(-/-) mice, suggesting that isopimpinellin induces Cyp2b10 via the CAR receptor. Overall, the current data indicate that naturally occurring coumarins have

  3. Induction of hepatic drug metabolizing enzymes by coal fly ash in rats

    SciTech Connect

    Srivastava, P.K.; Singh, Y.; Tyagi, S.R.; Misra, U.K.

    1987-12-01

    The effect of intratracheal administration of fly ash, its benzene-extracted residue and the benzene extract has been studied on the activities of hepatic mixed-function oxidases in the rat. Fly ash and its fractions significantly increased the levels of cytochrome P-450, cytochrome b/sub 5/, cytochrome b/sub 5/ reductase, NADPH-cytochrome c reductase, aminopyrine N-demethylase, aniline hydroxylase, and glutathione S-transferase in a dose-dependent manner. Phenobarbital or 3-methylcholanthrene treatment along with the administration of fly ash or its fractions showed an additive effect on the activities of the mixed-function oxidases. The observed effects were due to chemical component, i.e., organic and inorganic fractions of fly ash, and not due to its particulate nature. This was shown by the administration of glass beads, which did not cause any alteration in the activities of hepatic mixed-function oxidases.

  4. Similarities and Differences in the Expression of Drug-Metabolizing Enzymes between Human Hepatic Cell Lines and Primary Human HepatocytesS⃞

    PubMed Central

    Guo, Lei; Dial, Stacey; Shi, Leming; Branham, William; Liu, Jie; Fang, Jia-Long; Green, Bridgett; Deng, Helen; Kaput, Jim

    2011-01-01

    In addition to primary human hepatocytes, hepatoma cell lines, and transfected nonhepatoma, hepatic cell lines have been used for pharmacological and toxicological studies. However, a systematic evaluation and a general report of the gene expression spectra of drug-metabolizing enzymes and transporters (DMETs) in these in vitro systems are not currently available. To fill this information gap and to provide references for future studies, we systematically characterized the basal gene expression profiles of 251 drug-metabolizing enzymes in untreated primary human hepatocytes from six donors, four commonly used hepatoma cell lines (HepG2, Huh7, SK-Hep-1, and Hep3B), and one transfected human liver epithelial cell line. A large variation in DMET expression spectra was observed between hepatic cell lines and primary hepatocytes, with the complete absence or much lower abundance of certain DMETs in hepatic cell lines. Furthermore, the basal DMET expression spectra of five hepatic cell lines are summarized, providing references for researchers to choose carefully appropriate in vitro models for their studies of drug metabolism and toxicity, especially for studies with drugs in which toxicities are mediated through the formation of reactive metabolites. PMID:21149542

  5. Modulation of hepatic drug metabolizing enzymes by dietary doses of thymoquinone in female New Zealand White rabbits.

    PubMed

    Elbarbry, Fawzy; Ragheb, Ahmed; Marfleet, Travis; Shoker, Ahmed

    2012-11-01

    Herbal medicines can affect drug metabolizing enzymes. Therefore the effect of thymoquinone (TQ), the active ingredient of black seeds, was examined on rabbit liver drug metabolizing enzymes. Two groups of New Zealand female rabbits received TQ at 10 and 20 mg/kg/day orally and a control group of six animals each were killed after 8 weeks. Blood and livers were harvested and the activity of cytochrome P450 (CYP) and phase II enzymes in the microsomal and cytosolic preparations were measured by HPLC and ELISA methods. The liver enzymes ALT/AST and albumin were similar in the three groups. CYP1A2, CYP3A4, but not CYP2E1, were significantly diminished by TQ treatment. Of the phase II enzymes, glutathione-S-transferase (GST) and glutathione peroxidase (GPx) were significantly induced by the high TQ dose, while the total glutathione levels were unaffected. Glutathione reductase (GR), on the other hand, was significantly induced in the two experimental groups. Thymoquinone has differential effects on CYP and phase II enzymes. Inhibition of some CYP enzyme activities may lead to a hazardous herb-drug interaction. Induction of GR activity may explain the salutatory effect of the black seeds in inhibiting the generation of bioactive metabolites known to promote carcinogenesis and oxidative cell damage. PMID:22422469

  6. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  7. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  8. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  9. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  10. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  11. Hepatic drug metabolism and adverse hepatic drug reactions.

    PubMed

    Schaffner, F

    1975-01-01

    Drugs and other chemicals are usually metabolized in the liver in the drug-metabolizing enzyme system. The metabolites sometimes bind with cellular macromolecules and injure the cell directly or serve as new antigens to create immunologic injury in a delayed fashion. The immediate or toxic injury is dose-dependent, predictable and zonal in the liver lobule, usually in the central region. Carbon tetrachloride intoxication and acetaminophen overdose are examples of injury resulting from microsomal metabolism. Other injuries related to microsomal metabolism are those produced by vinyl chloride in polymerization plant workers and by methotrexate in psoriatics or leukemic children. Most adverse drug reactions affecting the liver and producing jaundice are unpredictable, delayed in onset, and only hypothetically related to microsomal metabolism in some instances. The two main types are cholestasis and viral-hepatitis-like. The former may be in a pure form, in which case it may be partly dose-dependent, or in a form mixed with hepatitis. Many drugs produce cholestasis in a small percentage of persons, and because the reaction is benign, albeit prolonged at times, such drugs continue to be used. The viral-hepatitis-like reaction involves few drugs and affects few persons, but can be fatal. The recognition that chronic hepatitis can be caused by drugs such as oxyphenisatin, alpha-methyldopa, and isoniazid has added a new dimension to the clinical problem of adverse drug reactions, which may extend to widely used and commonly available agents like aspirin. PMID:171822

  12. Induction of drug metabolizing enzymes by sulfinpyrazone.

    PubMed

    Walter, E; Staiger, C; de Vries, J; Zimmermann, R; Weber, E

    1981-01-01

    A previous interaction study of sulfinpyrazone (Anturano) suggested that it induced microsomal drug metabolizing enzymes in the liver. To verify this finding the effect of sulfinpyrazone 800 mg per day for four weeks was investigated in ten healthy volunteers. Both the therapeutic actions of sulfinpyrazone, the uricosuric and the antiaggregating effects, were demonstrated (p less than 0.05). The influence on the microsomal drug metabolizing system in the liver was demonstrated by an increase in serum-gamma-glutamyl transpeptidase from 15.1 to 23.3 U/l (p greater than 0.05), a significant increase in the urinary excretion of d-glucaric acid (29.6 to 77.9 microMol/24 h, p less than 0.05) and an increase in antipyrine clearance from 50.3 ml/min to 83.9 ml/min (p less than 0.05). The possibility of enhancement of drug metabolism during treatment with sulfinpyrazone in combination with other drugs should be kept in mind. PMID:6113147

  13. Chemoprotective activity of boldine: modulation of drug-metabolizing enzymes.

    PubMed

    Kubínová, R; Machala, M; Minksová, K; Neca, J; Suchý, V

    2001-03-01

    Possible chemoprotective effects of the naturally occurring alkaloid boldine, a major alkaloid of boldo (Peumus boldus Mol.) leaves and bark, including in vitro modulations of drug-metabolizing enzymes in mouse hepatoma Hepa-1 cell line and mouse hepatic microsomes, were investigated. Boldine manifested inhibition activity on hepatic microsomal CYP1A-dependent 7-ethoxyresorufin O-deethylase and CYP3A-dependent testosterone 6 beta-hydroxylase activities and stimulated glutathione S-transferase activity in Hepa-1 cells. In addition to the known antioxidant activity, boldine could decrease the metabolic activation of other xenobiotics including chemical mutagens. PMID:11265593

  14. Mechanism-based inhibitory and peroxisome proliferator-activated receptor α-dependent modulating effects of silybin on principal hepatic drug-metabolizing enzymes.

    PubMed

    Wang, Hong; Yan, Tingting; Xie, Yuan; Zhao, Min; Che, Yuan; Zhang, Jun; Liu, Huiying; Cao, Lijuan; Cheng, Xuefang; Xie, Yang; Li, Feiyan; Qi, Qu; Wang, Guangji; Hao, Haiping

    2015-04-01

    Silybin, a major pharmacologically active compound in silymarin, has been widely used in combination with other prescriptions in the clinic to treat hepatitis and a host of other diseases. Previous studies suggested that silybin is a potential inhibitor of multiple drug-metabolizing enzymes (DMEs); however, the in vitro to in vivo translation and the mechanisms involved remain established. The aim of this study was to provide a mechanistic understanding of the regulatory effects of silybin on principal DMEs. Silybin (50 or 150 mg/kg/d) was administered to mice for a consecutive 14 days. The plasma and hepatic exposure of silybin were detected; the mRNA, protein levels, and enzyme activities of principal DMEs were determined. The results demonstrated that the enzyme activities of CYP1A2, CYP2C, CYP3A11, and UGT1A1 were significantly repressed, whereas little alteration of the mRNA and protein levels was observed. Silybin inhibits these DMEs in a mechanism-based and/or substrate-competitive manner. More importantly, silybin was found to be a weak agonist of peroxisome proliferator-activated receptor (PPAR)α, as evidenced from the molecular docking, reporter gene assay, and the targeting gene expression analysis. However, silybin could significantly compromise the activation of PPARα by fenofibrate, characterized with significantly repressed expression of PPARα targeting genes, including L-FABP, ACOX1, and UGT1A6. This study suggests that silybin, despite its low bioavailability, may inhibit enzyme activities of multiple DMEs in a mechanism-based mode, and more importantly, may confer significant drug-drug interaction with PPARα agonists via the repression of PPARα activation in a competitive mode. PMID:25587127

  15. Alteration of drug metabolizing enzymes in sulphite oxidase deficiency

    PubMed Central

    Tutuncu, Begum; Kuçukatay, Vural; Arslan, Sevki; Sahin, Barbaros; Semiz, Asli; Sen, Alaattin

    2012-01-01

    The aim of this study was to investigate the possible effects of sulphite oxidase (SOX, E.C. 1.8.3.1) deficiency on xenobiotic metabolism. For this purpose, SOX deficiency was produced in rats by the administration of a low molybdenum diet with concurrent addition of 200 ppm tungsten to their drinking water. First, hepatic SOX activity in deficient groups was measured to confirm SOX deficiency. Then, aminopyrine N-demethylase, aniline 4-hydroxylase, aromatase, caffeine N-demethylase, cytochrome b5 reductase, erythromycin N-demethylase, ethoxyresorufin O-deethylase, glutathione S-transferase, N-nitrosodimethylamine N-demethylase and penthoxyresorufin O-deethylase activities were determined to follow changes in the activity of drug metabolizing enzymes in SOX-deficient rats. Our results clearly demonstrated that SOX deficiency significantly elevated A4H, caffeine N-demethylase, erythromycin N-demethylase and N-nitrosodimethylamine N-demethylase activities while decreasing ethoxyresorufin O-deethylase and aromatase activities. These alterations in drug metabolizing enzymes can contribute to the varying susceptibility and response of sulphite-sensitive individuals to different drugs and/or therapeutics used for treatments. PMID:22798713

  16. Role of constitutive androstane receptor in Toll-like receptor-mediated regulation of gene expression of hepatic drug-metabolizing enzymes and transporters.

    PubMed

    Shah, Pranav; Guo, Tao; Moore, David D; Ghose, Romi

    2014-01-01

    Impairment of drug disposition in the liver during inflammation has been attributed to downregulation of gene expression of drug-metabolizing enzymes (DMEs) and drug transporters. Inflammatory responses in the liver are primarily mediated by Toll-like receptors (TLRs). We have recently shown that activation of TLR2 or TLR4 by lipoteichoic acid (LTA) and lipopolysaccharide (LPS), respectively, leads to the downregulation of gene expression of DMEs/transporters. However, the molecular mechanism underlying this downregulation is not fully understood. The xenobiotic nuclear receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR), regulate the expression of DMEs/transporter genes. Downregulation of DMEs/transporters by LTA or LPS was associated with reduced expression of PXR and CAR genes. To determine the role of CAR, we injected CAR(+/+) and CAR(-/-) mice with LTA or LPS, which significantly downregulated (~40%-60%) RNA levels of the DMEs, cytochrome P450 (Cyp)3a11, Cyp2a4, Cyp2b10, uridine diphosphate glucuronosyltransferase 1a1, amine N-sulfotransferase, and the transporter, multidrug resistance-associated protein 2, in CAR(+/+) mice. Suppression of most of these genes was attenuated in LTA-treated CAR(-/-) mice. In contrast, LPS-mediated downregulation of these genes was not attenuated in CAR(-/-) mice. Induction of these genes by mouse CAR activator 1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene was sustained in LTA- but not in LPS-treated mice. Similar observations were obtained in humanized CAR mice. We have replicated these results in primary hepatocytes as well. Thus, LPS can downregulate DME/transporter genes in the absence of CAR, whereas the effect of LTA on these genes is attenuated in the absence of CAR, indicating the potential involvement of CAR in LTA-mediated downregulation of DME/transporter genes. PMID:24194512

  17. A Comparative Study for the Evaluation of Two Doses of Ellagic Acid on Hepatic Drug Metabolizing and Antioxidant Enzymes in the Rat

    PubMed Central

    Celik, Gurbet; Semiz, Aslı; Karakurt, Serdar; Arslan, Sevki; Adali, Orhan; Sen, Alaattin

    2013-01-01

    The present study was designed to evaluate different doses of ellagic acid (EA) in vivo in rats for its potential to modulate hepatic phases I, II, and antioxidant enzymes. EA (10 or 30 mg/kg/day, intragastrically) was administered for 14 consecutive days, and activity, protein, and mRNA levels were determined. Although the cytochrome P450 (CYP) 2B and CYP2E enzyme activities were decreased significantly, the activities of all other enzymes were unchanged with the 10 mg/kg/day EA. In addition, western-blot and qRT-PCR results clearly corroborated the above enzyme expressions. On the other hand, while the NAD(P)H:quinone oxidoreductase 1 (NQO1), catalase (CAT), glutathione peroxidase (GPX), and glutathione S-transferase (GST) activities were increased significantly, CYP1A, 2B, 2C, 2E, and 19 enzyme activities were reduced significantly with 30 mg/kg/day EA. In addition, CYP2B, 2C6, 2E1, and 19 protein and mRNA levels were substantially decreased by the 30 mg/kg/day dose of EA, but the CYP1A protein, and mRNA levels were not changed. CYP3A enzyme activity, protein and mRNA levels were not altered by neither 10 nor 30 mg/kg/day ellagic acid. These results indicate that EA exerts a dose-dependent impact on the metabolism of chemical carcinogens and drugs by affecting the enzymes involved in xenobiotics activation/detoxification and antioxidant pathways. PMID:23971029

  18. Use of immobilized enzymes in drug metabolism studies.

    PubMed

    Dulik, D M; Fenselau, C

    1988-04-01

    The immobilization of drug-metabolizing enzymes onto polymeric supports offers several advantages over use of conventional microsomal or soluble enzyme preparations. These include increased storage stability, facilitated separation of products from the incubation mixture, the ability to recover and reuse the enzyme catalyst, and in many cases, stabilization of the tertiary structure of membrane-bound enzymes. Attachment of the protein to the solid support may be accomplished by adsorption, covalent bonding, or entrapment techniques. This methodology has been successfully utilized for studies with such enzymes as cytochrome P-450, UDP-glucuronyltransferases, glutathione S-transferases, S-methyltransferases, and N-acetyltransferases. Although often employed for the synthesis of xenobiotic metabolites, immobilized enzymes have been used for mechanistic and relative reactivity studies, limited kinetic studies, and extracorporeal detoxification. Co-immobilization of multiple drug-metabolizing enzyme systems has made possible the sequential formation of metabolites arising from oxidation followed by conjugation. Immobilized enzymes may also be used in the prediction of species-dependent metabolic pathways. The potential for large-scale synthesis of drug metabolites using this methodology has been explored. PMID:3127263

  19. Inhibitory action of Epilobium hirsutum extract and its constituent ellagic acid on drug-metabolizing enzymes.

    PubMed

    Celik, Gurbet; Semiz, Aslı; Karakurt, Serdar; Gencler-Ozkan, Ayse Mine; Arslan, Sevki; Adali, Orhan; Sen, Alaattin

    2016-04-01

    Epilobium hirsutum (EH) is a medicinal plant for treating various diseases. Despite its wide usage, there is no available information about its potential influences on drug metabolism. The present study was undertaken to determine the in vivo effects of EH on hepatic CYP2B, CYP2C, CYP2D, and CYP3A enzymes that are primarily involved in drug metabolism. Male Wistar rats were injected intraperitoneally with EH water extract (EHWE) and ellagic acid (EA) at a daily dose of 37.5 and 20 mg/kg, respectively, for 9 days and hepatic drug-metabolizing enzymes were assessed at activity, protein and mRNA levels. Erythromycin N-demethylase activity was inhibited by 53 and 21 % in EHWE- and EA-treated rats, respectively. Benzphetamine N-demethylase and 7-benzyloxyresorufin-O-debenzylase activities were decreased by 53 and 43 %, and 57 and 57 % in EHWE-and EA-treated rats, respectively. Moreover, protein levels of CYP2B1, CYP2C6, CYP2D2, and CYP3A1 also decreased by 55, 15, 33, and 82 % as a result of EHWE treatment of rats, respectively. Similarly, CYP2B1, CYP2C6, CYP2D2, and CYP3A1 protein levels decreased by 62, 63, 49, and 37 % with EA treatment, respectively. qRT-PCR analyses also showed that mRNA levels of these enzymes were significantly inhibited with bothEHWE and EA treatments. In conclusion, inhibition of drug clearances leading to drug toxicity because of the lowered activity and expression of drug-metabolizing enzymes might be observed in the people who used EH as complementary herbal remedy that might be contributed by its EA content. PMID:25425117

  20. Regulation of drug-metabolizing enzymes by local and systemic liver injuries

    PubMed Central

    Guo, Yan; Hu, Bingfang; Xie, Yang; Billiar, Timothy R.; Sperry, Jason L.; Huang, Min; Xie, Wen

    2016-01-01

    Introduction Drug metabolism and disposition are critical in maintaining the chemical and functional homeostasis of xenobiotics/drugs and endobiotics. The liver plays an essential role in drug metabolism and disposition due to its abundant expression of drug-metabolizing enzymes (DMEs) and transporters. There is growing evidence to suggest that many hepatic and systemic diseases can affect drug metabolism and disposition by regulating the expression and/or activity of DMEs and transporters in the liver. Areas covered This review focuses on the recent progress on the regulation of DMEs by local and systemic liver injuries. Liver ischemia and reperfusion (I/R) and sepsis are used as examples of local and systemic injury, respectively. The reciprocal effect of the expression and activity of DMEs on animals' sensitivity to local and systemic liver injuries is also discussed. Expert opinion Local and systemic liver injuries have a major effect on the expression and activity of DMEs in the liver. Understanding the disease effect on DMEs is clinically important due to the concern of disease-drug interactions. Future studies are necessary to understand the mechanism by which liver injury regulates DMEs. Human studies are also urgently needed in order to determine whether the results in animals can be replicated in human patients. PMID:26751558

  1. Targeting drug-metabolizing enzymes for effective chemoprevention and chemotherapy.

    PubMed

    Swanson, Hollie I; Njar, Vincent C O; Yu, Zhen; Castro, David J; Gonzalez, Frank J; Williams, David E; Huang, Ying; Kong, Ah-Ng T; Doloff, Joshua C; Ma, Jie; Waxman, David J; Scott, Emily E

    2010-04-01

    The primary focus of chemoprevention research is the prevention of cancer using pharmacological, biological, and nutritional interventions. Chemotherapeutic approaches that have been used successfully for both the prevention and treatment of a number of human malignancies have arisen from the identification of specific agents and appropriate molecular targets. Although drug-metabolizing enzymes have historically been targeted in attempts to block the initial, genotoxic events associated with the carcinogenic process, emerging evidence supports the idea that manipulating drug-metabolizing enzymes may also be an effective strategy to be used for treating tumor progression, invasion, and, perhaps, metastasis. This report summarizes a symposium that presents some recent progress in this area. One area of emphasis is the development of a CYP17 inhibitor for treatment of prostate cancer that may also have androgen-independent anticancer activity at higher concentrations. A second focus is the use of a mouse model to investigate the effects of aryl hydrocarbon receptor and Cyp1b1 status and chemopreventative agents on transplacental cancer. A third area of focus is the phytochemical manipulation of not only cytochrome P450 (P450) enzymes but also phase II inflammatory and antioxidant enzymes via the nuclear factor-erythroid 2-related factor 2 pathway to block tumor progression. A final highlight is the use of prodrugs activated by P450 enzymes to halt tumor growth and considerations of dosing schedule and targeted delivery of the P450 transgene to tumor tissue. In addition to highlighting recent successes in these areas, limitations and areas that should be targeted for further investigation are discussed. PMID:20233842

  2. Targeting Drug-Metabolizing Enzymes for Effective Chemoprevention and Chemotherapy

    PubMed Central

    Swanson, Hollie I.; Njar, Vincent C. O.; Yu, Zhen; Castro, David J.; Gonzalez, Frank J.; Williams, David E.; Huang, Ying; Kong, Ah-Ng T.; Doloff, Joshua C.; Ma, Jie; Waxman, David J.

    2010-01-01

    The primary focus of chemoprevention research is the prevention of cancer using pharmacological, biological, and nutritional interventions. Chemotherapeutic approaches that have been used successfully for both the prevention and treatment of a number of human malignancies have arisen from the identification of specific agents and appropriate molecular targets. Although drug-metabolizing enzymes have historically been targeted in attempts to block the initial, genotoxic events associated with the carcinogenic process, emerging evidence supports the idea that manipulating drug-metabolizing enzymes may also be an effective strategy to be used for treating tumor progression, invasion, and, perhaps, metastasis. This report summarizes a symposium that presents some recent progress in this area. One area of emphasis is the development of a CYP17 inhibitor for treatment of prostate cancer that may also have androgen-independent anticancer activity at higher concentrations. A second focus is the use of a mouse model to investigate the effects of aryl hydrocarbon receptor and Cyp1b1 status and chemopreventative agents on transplacental cancer. A third area of focus is the phytochemical manipulation of not only cytochrome P450 (P450) enzymes but also phase II inflammatory and antioxidant enzymes via the nuclear factor-erythroid 2-related factor 2 pathway to block tumor progression. A final highlight is the use of prodrugs activated by P450 enzymes to halt tumor growth and considerations of dosing schedule and targeted delivery of the P450 transgene to tumor tissue. In addition to highlighting recent successes in these areas, limitations and areas that should be targeted for further investigation are discussed. PMID:20233842

  3. Cadmium effect on microsomal drug-metabolizing enzyme activity in rat livers with respect to differences in age and sex

    SciTech Connect

    Ando, M.

    1982-04-01

    The effect of cadmium on the hepatic microsomal drug-metabolizing enzyme system was investigated. Cadmium chloride caused the conversion of cytochrome P-450 to P-420 in rat liver microsomes. The destruction of cytochrome P-450 by cadmium caused the reduction of microsomal drug-metabolizing enzyme activity and prolonged the pentobarbital sleeping time. There is a sex-related difference in the ability of cadmium to inhibit the hepatic drug metabolism in rats: male rats are more sensitive to cadmium than females. The effective period when cadmium prolonged their sleep depended upon the age of rats; older rats were more sensitive to cadmium than younger ones. The maximum increase of sleeping time depended upon the dose level of cadium, and the rate constant of the equations seems to depend upon the age of the animals.

  4. EFFECTS OF PENTACHLOROPHENOL ON HEPATIC DRUG-METABOLIZING ENZYMES AND PORPHYRIA RELATED TO CONTAMINATION WITH CHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS

    EPA Science Inventory

    The hepatic effects of technical and pure grade pentachlorophenol were investigated in female rats fed 20, 100 and 500 ppm of each for 8 months. Technical pentachlorophenol was contaminated with 8 ppm hexa-, 520 ppm hepta-, and 1380 ppm octachlorodibenzodioxins; pure pentachlorop...

  5. Hepatic drug metabolizing profile of Flinders Sensitive Line rat model of depression.

    PubMed

    Kotsovolou, Olga; Ingelman-Sundberg, Magnus; Lang, Matti A; Marselos, Marios; Overstreet, David H; Papadopoulou-Daifoti, Zoi; Johanson, Inger; Fotopoulos, Andrew; Konstandi, Maria

    2010-08-16

    The Flinders Sensitive Line (FSL) rat model of depression exhibits some behavioral, neurochemical, and pharmacological features that have been reported in depressed patients and has been very effective in screening antidepressants. Major factor that determines the effectiveness and toxicity of a drug is the drug metabolizing capacity of the liver. Therefore, in order to discriminate possible differentiation in the hepatic drug metabolism between FSL rats and Sprague-Dawley (SD) controls, their hepatic metabolic profile was investigated in this study. The data showed decreased glutathione (GSH) content and glutathione S-transferase (GST) activity and lower expression of certain major CYP enzymes, including the CYP2B1, CYP2C11 and CYP2D1 in FSL rats compared to SD controls. In contrast, p-nitrophenol hydroxylase (PNP), 7-ethoxyresorufin-O-dealkylase (EROD) and 16alpha-testosterone hydroxylase activities were higher in FSL rats. Interestingly, the wide spread environmental pollutant benzo(alpha)pyrene (B(alpha)P) induced CYP1A1, CYP1A2, CYP2B1/2 and ALDH3c at a lesser extend in FSL than in SD rats, whereas the antidepressant mirtazapine (MIRT) up-regulated CYP1A1/2, CYP2C11, CYP2D1, CYP2E1 and CYP3A1/2, mainly, in FSL rats. The drug also further increased ALDH3c whereas suppressed GSH content in B(alpha)P-exposed FSL rats. In conclusion, several key enzymes of the hepatic biotransformation machinery are differentially expressed in FSL than in SD rats, a condition that may influence the outcome of drug therapy. The MIRT-induced up-regulation of several drug-metabolizing enzymes indicates the critical role of antidepressant treatment that should be always taken into account in the designing of treatment and interpretation of insufficient pharmacotherapy or drug toxicity. PMID:20595028

  6. In vitro effects of the citrus flavonoids diosmin, naringenin and naringin on the hepatic drug-metabolizing CYP3A enzyme in human, pig, mouse and fish.

    PubMed

    Burkina, Viktoriia; Zlabek, Vladimir; Halsne, Ruth; Ropstad, Erik; Zamaratskaia, Galia

    2016-06-15

    Flavonoids are known to have effects on cytochrome P450 enzymatic activity. However, little effort has been made to examine species differences and the relevance of studies on mammalian and fish microsomes so that extrapolations can be made to humans. Therefore, the effects of several naturally occurring flavonoids on the activity of CYP3A-dependent 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylase (BFCOD) were evaluated in human, pig, mouse, and juvenile rainbow trout sources of hepatic microsomes. Each was exposed to three concentrations (1, 10, and 100μM) of diosmin, naringin, and naringenin. Naringenin competitively inhibited BFCOD activity (Ki values were 24.6μM in human, 15.6μM in pig, and 19.6μM in mouse microsomes). In fish, BFCOD activity was inhibited in a noncompetitive manner (Ki=7μM). Neither diosmin nor naringenin affected BFCOD activity in hepatic microsomes from the studied model organisms. These results suggest that dietary flavonoids potentially inhibit the metabolism of clinical drugs. PMID:27107807

  7. Hepatic drug metabolism and lipid peroxidation in thiamine deficient rats.

    PubMed

    Galdhar, N R; Pawar, S S

    1976-01-01

    In vitro metabolism of aminopyrene, ethylmorphine (Type I substrates), N-methylaniline and acetanilide (Type II substrates) in liver microsomal fraction from thiamine deficient male and female rats was studied. No significant change in microsomal protein content was noticed during the period of thiamine deficiency. However, a significant increase in the in vitro oxidation of aminopyrene, ethylmorphine, N-methylaniline and hydroxylation of acetanilide was observed. The NADPH linked and ascorbate induced lipid peroxidation was also increased during thiamine deficiency. The levels of NADPH cytochrome c-reductase, cytochrome b5 and heme were noticeably increased in thiamine deficient animals as compared to normal rats. Phenobarbital treatment induced the activities of all drug enzymes and inhibited the lipid peroxidation in either sex during the period of thiamine deficiency. It appears that thiamine intake is an important determination in drug metabolism and lipid peroxidation. PMID:816749

  8. Pharmacological basis for hepatic drug metabolism in sheep.

    PubMed

    Galtier, P; Alvinerie, M

    1996-01-01

    Age-related changes in hepatic drug metabolizing activities of Lacaune ewes were determined in foetal, neonatal, growing, pregnant and adult animals. The ontogenic evolution of cytochrome P450 was compared to those of microsomal monooxygenases and some microsomal and cytosolic transferases. The involvement of two purified izoenzymes P4502B and P4503A was determined in the N-demethylation of various substrates and the hydroxylations of progesterone. An experimental fascioliasis, provoked by the oral administration of 150 metacercariae of Fasciola hepatica to sheep, was proposed as a pathological model. Its effect was measured on the pharmacokinetics of various hepatic tracers and veterinary drugs. The mean residence times of antipyrine, pentobarbital, albendazole and mebendazole were increased in infected lambs with consequences on the urinary excretion of 4-hydroxyantipyrine, prolongation of pentobarbital-induced sleeping time, elimination of albendazole sulfone and reduced mebendazole. The characteristic decrease in liver cytochrome P450 could be responsible for most of the pharmacokinetic and pharmacodynamic changes observed in fluke-infected ruminants. PMID:8822607

  9. Pharmacogenetics of drug-metabolizing enzymes in US Hispanics

    PubMed Central

    Duconge, Jorge; Cadilla, Carmen L.; Ruaño, Gualberto

    2015-01-01

    Although the Hispanic population is continuously growing in the United States, they are underrepresented in pharmacogenetic studies. This review addresses the need for compiling available pharmacogenetic data in US Hispanics, discussing the prevalence of clinically relevant polymorphisms in pharmacogenes encoding for drug-metabolizing enzymes. CYP3A5*3 (0.245–0.867) showed the largest frequency in a US Hispanic population. A higher prevalence of CYP2C9*3, CYP2C19*4, and UGT2B7 IVS1+985 A>Gwas observed in US Hispanic vs. non-Hispanic populations. We found interethnic and intraethnic variability in frequencies of genetic polymorphisms for metabolizing enzymes, which highlights the need to define the ancestries of participants in pharmacogenetic studies. New approaches should be integrated in experimental designs to gain knowledge about the clinical relevance of the unique combination of genetic variants occurring in this admixed population. Ethnic subgroups in the US Hispanic population may harbor variants that might be part of multiple causative loci or in linkage-disequilibrium with functional variants. Pharmacogenetic studies in Hispanics should not be limited to ascertain commonly studied polymorphisms that were originally identified in their parental populations. The success of the Personalized Medicine paradigm will depend on recognizing genetic diversity between and within US Hispanics and the uniqueness of their genetic backgrounds. PMID:25431893

  10. Role of Adaptor Protein Toll-Like Interleukin Domain Containing Adaptor Inducing Interferon β in Toll-Like Receptor 3- and 4-Mediated Regulation of Hepatic Drug Metabolizing Enzyme and Transporter Genes.

    PubMed

    Shah, Pranav; Omoluabi, Ozozoma; Moorthy, Bhagavatula; Ghose, Romi

    2016-01-01

    The expressions and activities of hepatic drug-metabolizing enzymes and transporters (DMETs) are altered during infection and inflammation. Inflammatory responses in the liver are mediated primarily by Toll-like receptor (TLR)-signaling, which involves recruitment of Toll/interleukin (IL)-1 receptor (TIR) domain containing adaptor protein (TIRAP) and TIR domain containing adaptor inducing interferon (IFN)-β (TRIF) that eventually leads to induction of proinflammatory cytokines and mitogen-activated protein kinases (MAPKs). Lipopolysaccharide (LPS) activates the Gram-negative bacterial receptor TLR4 and polyinosinic:polycytidylic acid (polyI:C) activates the viral receptor TLR3. TLR4 signaling involves TIRAP and TRIF, whereas TRIF is the only adaptor protein involved in the TLR3 pathway. We have shown previously that LPS-mediated downregulation of DMETs is independent of TIRAP. To determine the role of TRIF, we treated TRIF(+/+) and TRIF(-/-) mice with LPS or polyI:C. LPS downregulated (∼40%-60%) Cyp3a11, Cyp2a4, Ugt1a1, Mrp2 mRNA levels, whereas polyI:C downregulated (∼30%-60%) Cyp3a11, Cyp2a4, Cyp1a2, Cyp2b10, Ugt1a1, Mrp2, and Mrp3 mRNA levels in TRIF(+/+) mice. This downregulation was not attenuated in TRIF(-/-) mice. Induction of cytokines by LPS was observed in both TRIF(+/+) and TRIF(-/-) mice. Cytokine induction was delayed in polyI:C-treated TRIF(-/-) mice, indicating that multiple mechanisms mediating polyI:C signaling exist. To assess the role of MAPKs, primary hepatocytes were pretreated with specific inhibitors before treatment with LPS/polyI:C. We found that only the c-jun-N-terminal kinase (JNK) inhibitor attenuated the down-regulation of DMETs. These results show that TRIF-independent pathways can be involved in the downregulation of DMETs through TLR4 and 3. JNK-dependent mechanisms likely mediate this downregulation. PMID:26470915

  11. Effects of formula composition on hepatic and intestinal drug metabolism during enteral nutrition.

    PubMed

    Knodell, R G

    1990-01-01

    Significant compositional differences in protein and lipid content are present in currently available enteral nutrition preparations. Since variations in dietary protein and/or lipid have previously been shown to produce alterations in liver and gut drug metabolism, effects of five commonly used enteral nutrition regimens on several drug metabolic parameters were assessed in rats. Study formulations included: 1) Vivonex: low protein -no lipid; 2) High Protein Vivonex: normal protein -no lipid; 3) Vital: normal protein -normal lipid; 4) Sustacal: high protein -high lipid; 5) Isocal: normal protein -high lipid. Hepatic and intestinal microsomes were prepared after a continuous 7-day intragastric infusion of one of the formulations, and measurements of cytochrome P-450 content and assays of drug metabolizing activity were performed. No differences in intestinal microsomal cytochrome P-450 content or meperidine demethylase activity were seen among the various alimentation groups. However, significantly decreased amounts of cytochrome P-450 and reduced meperidine demethylase and pentobarbital hydroxylase activity were present in hepatic microsomes of animals receiving the lipid-poor Vivonex and High Nitrogen Vivonex preparations compared to the other alimentation groups. These data suggest that the composition of enteral nutrition formulations may significantly impact on hepatic function and specifically that the presence of lipid in such preparations may be important for maintaining normal levels of hepatic drug metabolism. PMID:2109111

  12. Proliferation of smooth endoplasmic reticulum and induction of microsomal drug-metabolizing enzymes after ether or halothane.

    PubMed

    Ross, W T; Cardell, R R

    1978-05-01

    Hepatic drug-metabolizing enzymes and hepatic ultrastructure were studied in rats after two hours of anesthesia with 1 MAC halothane or diethyl ether. Twelve hours after cessation of either anesthetic smooth endoplasmic reticulum was increased in centrilobular but not in periportal hepatocytes. This change persisted at 24- and 36-hour sampling times. Microsomal cytochrome P450 and cytochrome b5 decreased after halothane anesthesia (by 7 to 20 per cent of control). Diethyl ether caused increased cytochrome P450 and cytochrome b5 (27 and 18 per cent, respectively) at the 36-hour sampling time. NADPH cytochrome c reductase did not change significantly after either agent. The authors interpret these results to mean that both agents promote conversion of rough endoplasmic reticulum to smooth endoplasmic reticulum or, alternatively, that the anesthetics decrease degradation of smooth endoplasmic membranes. Since only ether caused an increase in the microsomal content of enzymes of the drug-metabolizing enzyme system, it is concluded that these two anesthetics act on hepatic cells by dissimilar mechanisms. PMID:646150

  13. Pharmacogenomics of drug metabolizing enzymes and transporters: implications for cancer therapy

    PubMed Central

    Li, Jing; Bluth, Martin H

    2011-01-01

    The new era of personalized medicine, which integrates the uniqueness of an individual with respect to the pharmacokinetics and pharmacodynamics of a drug, holds promise as a means to provide greater safety and efficacy in drug design and development. Personalized medicine is particularly important in oncology, whereby most clinically used anticancer drugs have a narrow therapeutic window and exhibit a large interindividual pharmacokinetic and pharmacodynamic variability. This variability can be explained, at least in part, by genetic variations in the genes encoding drug metabolizing enzymes, transporters, or drug targets. Understanding of how genetic variations influence drug disposition and action could help in tailoring cancer therapy based on individual’s genetic makeup. This review focuses on the pharmacogenomics of drug metabolizing enzymes and drug transporters, with a particular highlight of examples whereby genetic variations in the metabolizing enzymes and transporters influence the pharmacokinetics and/or response of chemotherapeutic agents. PMID:23226051

  14. Fasting-Induced Changes in Hepatic P450 Mediated Drug Metabolism Are Largely Independent of the Constitutive Androstane Receptor CAR

    PubMed Central

    de Vries, E. M.; Lammers, L. A.; Achterbergh, R.; Klümpen, H-J; Mathot, R. A. A.; Boelen, A.; Romijn, J. A.

    2016-01-01

    Introduction Hepatic drug metabolism by cytochrome P450 enzymes is altered by the nutritional status of patients. The expression of P450 enzymes is partly regulated by the constitutive androstane receptor (CAR). Fasting regulates the expression of both P450 enzymes and CAR and affects hepatic drug clearance. We hypothesized that the fasting-induced alterations in P450 mediated drug clearance are mediated by CAR. Methods To investigate this we used a drug cocktail validated in humans consisting of five widely prescribed drugs as probes for specific P450 enzymes: caffeine (CYP1A2), metoprolol (CYP2D6), omeprazole (CYP2C19), midazolam (CYP3A4) and s-warfarin (CYP2C9). This cocktail was administered to wild type (WT, C57Bl/6) mice or mice deficient for CAR (CAR-/-) that were either fed ad libitum or fasted for 24 hours. Blood was sampled at predefined intervals and drug concentrations were measured as well as hepatic mRNA expression of homologous/orthologous P450 enzymes (Cyp1a2, Cyp2d22, Cyp3a11, Cyp2c37, Cyp2c38 and Cyp2c65). Results Fasting decreased Cyp1a2 and Cyp2d22 expression and increased Cyp3a11 and Cyp2c38 expression in both WT and CAR-/- mice. The decrease in Cyp1a2 was diminished in CAR-/- in comparison with WT mice. Basal Cyp2c37 expression was lower in CAR-/- compared to WT mice. Fasting decreased the clearance of all drugs tested in both WT and CAR-/- mice. The absence of CAR was associated with an decrease in the clearance of omeprazole, metoprolol and midazolam in fed mice. The fasting-induced reduction in clearance of s-warfarin was greater in WT than in CAR-/-. The changes in drug clearance correlated with the expression pattern of the specific P450 enzymes in case of Cyp1a2-caffeine and Cyp2c37-omeprazole. Conclusion We conclude that CAR is important for hepatic clearance of several widely prescribed drugs metabolized by P450 enzymes. However the fasting-induced alterations in P450 mediated drug clearance are largely independent of CAR. PMID

  15. Biotransformation of anthelmintics and the activity of drug-metabolizing enzymes in the tapeworm Moniezia expansa.

    PubMed

    Prchal, Lukáš; Bártíková, Hana; Bečanová, Aneta; Jirásko, Robert; Vokřál, Ivan; Stuchlíková, Lucie; Skálová, Lenka; Kubíček, Vladimír; Lamka, Jiří; Trejtnar, František; Szotáková, Barbora

    2015-04-01

    The sheep tapeworm Moniezia expansa is very common parasite, which affects ruminants such as sheep, goats as well as other species. The benzimidazole anthelmintics albendazole (ABZ), flubendazole (FLU) and mebendazole (MBZ) are often used to treat the infection. The drug-metabolizing enzymes of helminths may alter the potency of anthelmintic treatment. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (ABZ, MBZ and FLU) in M. expansa. Activities of biotransformation enzymes were determined in subcellular fractions. Metabolites of the anthelmintics were detected and identified using high performance liquid chromatography/ultra-violet/VIS/fluorescence or ultra-high performance liquid chromatography/mass spectrometry. Reduction of MBZ, FLU and oxidation of ABZ were proved as well as activities of various metabolizing enzymes. Despite the fact that the conjugation enzymes glutathione S-transferase, UDP-glucuronosyl transferase and UDP-glucosyl transferase were active in vitro, no conjugated metabolites of anthelmintics were identified either ex vivo or in vitro. The obtained results indicate that sheep tapeworm is able to deactivate the administered anthelmintics, and thus protects itself against their action. PMID:25373326

  16. Nerve agent hydrolysis activity designed into a human drug metabolism enzyme.

    PubMed

    Hemmert, Andrew C; Otto, Tamara C; Chica, Roberto A; Wierdl, Monika; Edwards, Jonathan S; Lewis, Steven M; Lewis, Steven L; Edwards, Carol C; Tsurkan, Lyudmila; Cadieux, C Linn; Kasten, Shane A; Cashman, John R; Mayo, Stephen L; Potter, Philip M; Cerasoli, Douglas M; Redinbo, Matthew R

    2011-01-01

    Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning. PMID:21445272

  17. Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme

    PubMed Central

    Hemmert, Andrew C.; Otto, Tamara C.; Chica, Roberto A.; Wierdl, Monika; Edwards, Jonathan S.; Lewis, Steven L.; Edwards, Carol C.; Tsurkan, Lyudmila; Cadieux, C. Linn; Kasten, Shane A.; Cashman, John R.; Mayo, Stephen L.; Potter, Philip M.; Cerasoli, Douglas M.; Redinbo, Matthew R.

    2011-01-01

    Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning. PMID:21445272

  18. Gene expression analysis of membrane transporters and drug-metabolizing enzymes in the lung of healthy and COPD subjects

    PubMed Central

    Berg, Tove; Hegelund Myrbäck, Tove; Olsson, Marita; Seidegård, Janeric; Werkström, Viktoria; Zhou, Xiao-Hong; Grunewald, Johan; Gustavsson, Lena; Nord, Magnus

    2014-01-01

    This study describes for the first time the expression levels of genes encoding membrane transporters and drug-metabolizing enzymes in the lungs of ex-smoking patients with chronic obstructive pulmonary disease (COPD). Membrane transporters and drug-metabolizing enzymes are key determinants of drug uptake, metabolism, and elimination for systemically administered as well as inhaled drugs, with consequent influence on clinical efficacy and patient safety. In this study, while no difference in gene expression was found between healthy and COPD subjects, we identified a significant regional difference in mRNA expression of both membrane transporters and drug-metabolizing enzymes between central and peripheral tissue in both healthy and COPD subjects. The majority of the differentially expressed genes were higher expressed in the central airways such as the transporters SLC2A1 (GLUT1), SLC28A3 (CNT3), and SLC22A4 (OCTN1) and the drug-metabolizing enzymes GSTZ1, GSTO2, and CYP2F1. Together, this increased knowledge of local pharmacokinetics in diseased and normal lung may improve modeling of clinical outcomes of new chemical entities intended for inhalation therapy delivered to COPD patients. In addition, based on the similarities between COPD and healthy subjects regarding gene expression of membrane transporters and drug-metabolizing enzymes, our results suggest that clinical pharmacological studies in healthy volunteers could be a valid model of COPD patients regarding drug disposition of inhaled drugs in terms of drug metabolism and drug transporters. PMID:25505599

  19. Effects of chronic kidney disease and uremia on hepatic drug metabolism and transport.

    PubMed

    Yeung, Catherine K; Shen, Danny D; Thummel, Kenneth E; Himmelfarb, Jonathan

    2014-03-01

    The pharmacokinetics of non-renally cleared drugs in patients with chronic kidney disease is often unpredictable. Some of this variability may be due to alterations in the expression and activity of extra renal drug-metabolizing enzymes and transporters, primarily localized in the liver and intestine. Studies conducted in rodent models of renal failure have shown decreased mRNA and protein expression of many members of the cytochrome P450 enzyme (CYP) gene family and the ATP-binding cassette (ABC) and solute carrier (SLC) gene families of drug transporters. Uremic toxins interfere with transcriptional activation, cause downregulation of gene expression mediated by proinflammatory cytokines, and directly inhibit the activity of the cytochrome P450s and drug transporters. While much has been learned about the effects of kidney disease on non-renal drug disposition, important questions remain regarding the mechanisms of these effects, as well as the interplay between drug-metabolizing enzymes and drug transporters in the uremic milieu. In this review, we have highlighted the existing gaps in our knowledge and understanding of the impact of chronic kidney disease on non-renal drug clearance, and identified areas of opportunity for future research. PMID:24132209

  20. Effect of commercially available green and black tea beverages on drug-metabolizing enzymes and oxidative stress in Wistar rats.

    PubMed

    Yao, Hsien-Tsung; Hsu, Ya-Ru; Lii, Chong-Kuei; Lin, Ai-Hsuan; Chang, Keng-Hao; Yang, Hui-Ting

    2014-08-01

    The effect of commercially available green tea (GT) and black tea (BT) drinks on drug metabolizing enzymes (DME) and oxidative stress in rats was investigated. Male Wistar rats were fed a laboratory chow diet and GT or BT drink for 5 weeks. Control rats received de-ionized water instead of the tea drinks. Rats received the GT and BT drinks treatment for 5 weeks showed a significant increase in hepatic microsomal cytochrome P450 (CYP) 1A1 and CYP1A2, and a significant decrease in CYP2C, CYP2E1 and CYP3A enzyme activities. Results of immunoblot analyses of enzyme protein contents showed the same trend with enzyme activity. Significant increase in UDP-glucuronosyltransferase activity and reduced glutathione content in liver and lungs were observed in rats treated with both tea drinks. A lower lipid peroxide level in lungs was observed in rats treated with GT drink. Electrophoretic mobility shift assay revealed that both tea drinks decreased pregnane X receptor binding to DNA and increased nuclear factor-erythroid 2 p45-related factor 2 binding to DNA. These results suggest that feeding of both tea drinks to rats modulated DME activities and reduced oxidative stress in liver and lungs. GT drink is more effective on reducing oxidative stress than BT drink. PMID:24815822

  1. Relevance of induction of human drug-metabolizing enzymes: pharmacological and toxicological implications

    PubMed Central

    PARK, B. K.; KITTERINGHAM, N. R.; PIRMOHAMED, M.; TUCKER, G. T.

    1996-01-01

    1Human drug-metabolizing systems can be induced, or activated, by a large number of exogenous agents including drugs, alcohol, components in the diet and cigarette smoke, as well as by endogenous factors. 2Such perturbation of enzyme activity undoubtedly contributes to both intra- and inter-individual variation both with respect to the rate and route of metabolism for a particular drug. Induction may, in theory, either attenuate the pharmacological response or exacerbate the toxicity of a particular drug, or both. 3The clinical impact of enzyme induction will depend upon the number of different enzyme isoforms affected and the magnitude of the inductive response within an individual, and also on the therapeutic indices of the affected substrates. 4The toxicological implications will be determined either by any change in the route of metabolism, or by a disturbance of the balance between activation and detoxication processes, which may be isozyme selective. PMID:8799511

  2. Drug Metabolism Enzyme Expression and Activity in Primary Cultures of Human Proximal Tubular Cells

    PubMed Central

    Lash, Lawrence H.; Putt, David A.; Cai, Hongliang

    2008-01-01

    We previously catalogued expression and activity of organic anion and cation, amino acid, and peptide transporters in primary cultures of human proximal tubular (hPT) cells to establish them as a cellular model to study drug transport in the human kidney [Toxicology 228, 200–218 (2006)]. Here, we extend our analysis to drug metabolism enzymes. Expression of 11 cytochrome P450 (CYP) enzymes was determined with specific antibodies. CYP1B1, CYP3A4, and CYP4A11 were the only CYP enzymes readily detected in total cell extracts. These same CYP enzymes, as well as CYP3A5 and possibly CYP2D6, were detected in microsomes from confluent hPT cells, although expression levels varied among kidney samples. In agreement with Western blot data, only activity of CYP3A4/5 was detected among the enzyme activities measured. Expression of all three glutathione S-transferases (GSTs) known to be found in hPT cells, GSTA, GSTP, and GSTT, was readily detected. Variable expression of three sulfotransferases (SULTs), SULT1A3, SULT1E, and SULT2A1, and three UDP-glucuronosyltransferases (UGTs), UGT1A1, UGT1A6, and UGT2B7, was also detected. When examined over the course of cell growth to confluence, expression of all enzymes was generally maintained at readily measurable levels, although they were often lower than in fresh tissue. These results indicate that primary cultures of hPT cells possess significant capacity to metabolize many classes of drugs, and can be used as an effective model to study drug metabolism. PMID:18055091

  3. Drug-metabolizing and antioxidant enzymes in monosodium L-glutamate obese mice.

    PubMed

    Matoušková, Petra; Bártíková, Hana; Boušová, Iva; Levorová, Lucie; Szotáková, Barbora; Skálová, Lenka

    2015-02-01

    The prevalence of obesity is rapidly increasing across the world. Physiologic alterations associated with obesity are known to alter enzyme expression and/or activities. As drug-metabolizing and antioxidant enzymes serve as defense system against potentially toxic compounds, their modulation might have serious consequences. In this work, we studied selected antioxidant and drug-metabolizing enzymes (DME) in monosodium glutamate-mouse model of obesity. Specific activities, protein, and mRNA expressions of these enzymes in liver as well as in small intestine were compared in obese male mice and in their lean counterparts. Furthermore, expression of the NF-E2-related factor 2 (Nrf2) and its relation to obesity were tested. Obtained results showed that obesity affects expression and/or activities of some DME and antioxidant enzymes. In obese mice, upregulation of UDP-glucuronosyltransferases 1A (UGT1A), NAD(P)H:quinone oxidoreductase 1 (NQO1), nuclear transcription factor Nrf2, and downregulation of some isoforms of glutathione S-transferases (GST) were observed. Most of these changes were tissue and/or isoform specific. NQO1 seems to be regulated transcriptionally via Nrf2, but other enzymes might be regulated post-transcriptionally and/or post-translationally. Enhanced expression of Nrf2 in livers of obese mice is expected to play a role in protective adaptation. In contrast, elevated activities of NQO1 and UGT1A may cause alterations in drug pharmacokinetics in obese individuals. Moreover, decreased capacity of GST in obese animals indicates potentially reduced antioxidant defense and weaker chemoprotection. PMID:25473020

  4. In vivo cytochrome P450 drug metabolizing enzyme characterization using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Yanfang; Bachmann, Kenneth A.; Cameron, Brent D.

    2003-07-01

    The development of a rapid, inexpensive, and accurate in vivo phenotyping methodology for characterizing drug-metabolizing phenotypes with reference to the cytochrome P450 (CYP450) enzymes would be very beneficial. In terms of application, in the wake of the human genome project, considerable interest is focused on the development of new drugs whose uses will be tailored to specific genetic polymorphisms, and on the individualization of dosing regimens that are also tailored to meet individual patient needs depending upon genotype. In this investigation, chemical probes for CYP450 enzymes were characterized and identified with Raman spectroscopy. Furthermore, gold-based metal colloid clusters were utilized to generate surface enhanced Raman spectra for each of the chemical probes. Results will be presented demonstrating the ability of SERS to identify minute quantities of these probes on the order needed for in vivo application.

  5. Dietary Isoflavones as Modulators of Drug Metabolizing Enzymes and Transporters: Effect on Prescription Medicines.

    PubMed

    Taneja, Isha; Raju, Kanumuri Siva Rama; Wahajuddin, Muhammad

    2016-07-29

    Isoflavones are the most widely consumed phytoestrogens. Besides being a dietary constituent, their consumption has been increasing in the form of herbal supplements and as promising alternatives to hormonal replacement therapy, in conjunction with prescription medicines. Isoflavones are extensively metabolized by phase I and II enzymes and are substrates of drug transporters. At high concentrations isoflavones may interact with drug metabolizing enzymes and drug transporters and modulate their activity, thus, altering the absorption, metabolism, distribution, excretion and toxicity profile of the co-administered drugs. This review summarizes the up-to-date literature of isoflavone-drug interactions giving insight into the possible mechanisms of interactions, in vitro-in vivo correlation and their implications on clinical outcomes. PMID:26561312

  6. A multiscale approach to modelling drug metabolism by membrane-bound cytochrome P450 enzymes.

    PubMed

    Lonsdale, Richard; Rouse, Sarah L; Sansom, Mark S P; Mulholland, Adrian J

    2014-07-01

    Cytochrome P450 enzymes are found in all life forms. P450s play an important role in drug metabolism, and have potential uses as biocatalysts. Human P450s are membrane-bound proteins. However, the interactions between P450s and their membrane environment are not well-understood. To date, all P450 crystal structures have been obtained from engineered proteins, from which the transmembrane helix was absent. A significant number of computational studies have been performed on P450s, but the majority of these have been performed on the solubilised forms of P450s. Here we present a multiscale approach for modelling P450s, spanning from coarse-grained and atomistic molecular dynamics simulations to reaction modelling using hybrid quantum mechanics/molecular mechanics (QM/MM) methods. To our knowledge, this is the first application of such an integrated multiscale approach to modelling of a membrane-bound enzyme. We have applied this protocol to a key human P450 involved in drug metabolism: CYP3A4. A biologically realistic model of CYP3A4, complete with its transmembrane helix and a membrane, has been constructed and characterised. The dynamics of this complex have been studied, and the oxidation of the anticoagulant R-warfarin has been modelled in the active site. Calculations have also been performed on the soluble form of the enzyme in aqueous solution. Important differences are observed between the membrane and solution systems, most notably for the gating residues and channels that control access to the active site. The protocol that we describe here is applicable to other membrane-bound enzymes. PMID:25033460

  7. A Multiscale Approach to Modelling Drug Metabolism by Membrane-Bound Cytochrome P450 Enzymes

    PubMed Central

    Sansom, Mark S. P.; Mulholland, Adrian J.

    2014-01-01

    Cytochrome P450 enzymes are found in all life forms. P450s play an important role in drug metabolism, and have potential uses as biocatalysts. Human P450s are membrane-bound proteins. However, the interactions between P450s and their membrane environment are not well-understood. To date, all P450 crystal structures have been obtained from engineered proteins, from which the transmembrane helix was absent. A significant number of computational studies have been performed on P450s, but the majority of these have been performed on the solubilised forms of P450s. Here we present a multiscale approach for modelling P450s, spanning from coarse-grained and atomistic molecular dynamics simulations to reaction modelling using hybrid quantum mechanics/molecular mechanics (QM/MM) methods. To our knowledge, this is the first application of such an integrated multiscale approach to modelling of a membrane-bound enzyme. We have applied this protocol to a key human P450 involved in drug metabolism: CYP3A4. A biologically realistic model of CYP3A4, complete with its transmembrane helix and a membrane, has been constructed and characterised. The dynamics of this complex have been studied, and the oxidation of the anticoagulant R-warfarin has been modelled in the active site. Calculations have also been performed on the soluble form of the enzyme in aqueous solution. Important differences are observed between the membrane and solution systems, most notably for the gating residues and channels that control access to the active site. The protocol that we describe here is applicable to other membrane-bound enzymes. PMID:25033460

  8. Correlating Structure and Function of Drug-Metabolizing Enzymes: Progress and Ongoing Challenges

    PubMed Central

    Johnson, Eric F.; Connick, J. Patrick; Reed, James R.; Backes, Wayne L.; Desai, Manoj C.; Xu, Lianhong; Estrada, D. Fernando; Laurence, Jennifer S.

    2014-01-01

    This report summarizes a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics at Experimental Biology held April 20-24 in Boston, MA. Presentations discussed the status of cytochrome P450 (P450) knowledge, emphasizing advances and challenges in relating structure with function and in applying this information to drug design. First, at least one structure of most major human drug-metabolizing P450 enzymes is known. However, the flexibility of these active sites can limit the predictive value of one structure for other ligands. A second limitation is our coarse-grain understanding of P450 interactions with membranes, other P450 enzymes, NADPH–cytochrome P450 reductase, and cytochrome b5. Recent work has examined differential P450 interactions with reductase in mixed P450 systems and P450:P450 complexes in reconstituted systems and cells, suggesting another level of functional control. In addition, protein nuclear magnetic resonance is a new approach to probe these protein/protein interactions, identifying interacting b5 and P450 surfaces, showing that b5 and reductase binding are mutually exclusive, and demonstrating ligand modulation of CYP17A1/b5 interactions. One desired outcome is the application of such information to control drug metabolism and/or design selective P450 inhibitors. A final presentation highlighted development of a CYP3A4 inhibitor that slows clearance of human immunodeficiency virus drugs otherwise rapidly metabolized by CYP3A4. Although understanding P450 structure/function relationships is an ongoing challenge, translational advances will benefit from continued integration of existing and new biophysical approaches. PMID:24130370

  9. Regulation of drug-metabolizing enzymes by xenobiotic receptors: PXR and CAR☆

    PubMed Central

    Tolson, Antonia H.; Wang, Hongbing

    2010-01-01

    Drug-metabolizing enzymes (DMEs) and transporters play pivotal roles in the disposition and detoxification of numerous foreign and endogenous chemicals. To accommodate chemical challenges, the expression of many DMEs and transporters is up-regulated by a group of ligand-activated transcription factors namely nuclear receptors (NRs). The importance of NRs in xenobiotic metabolism and clearance is best exemplified by the most promiscuous xenobiotic receptors: pregnane X receptor (PXR, NR1I2) and constitutive androstane/activated receptor (CAR, NR1I3). Together, these two receptors govern the inductive expression of a largely overlapping array of target genes encoding phase I and II DMEs, and drug transporters. Moreover, PXR and CAR also represent two distinctive mechanisms of NR activation, whereby CAR demonstrates both constitutive and ligand-independent activation. In this review, recent advances in our understanding of PXR and CAR as xenosensors are discussed with emphasis placed on the differences rather than similarities of these two xenobiotic receptors in ligand recognition and target gene regulation. PMID:20727377

  10. Effect of hexavalent chromium on drug-metabolizing enzymes in male domesticated rabbits.

    PubMed

    Anjum, F; Shakoori, A R; Gorrod, J W

    1996-01-01

    We studied the effect of chromium on the drug-metabolizing enzymes (DME) in male New Zealand white rabbits, Oryctolagus cuniculus, with and without pretreatment with phenobarbitone (PB) and promethazine (PM). The activities of cytochrome P-450 (183%), aniline hydroxylase (ANH, 265%), acetanilide hydroxylase (ACH, 160%), benzphetamine demethylase (BD, 112%), aminopyrine demethylase (AD, 97%), N,N,-dimethyl aniline demethylase (DAD, 72%), and cytochrome-c-reductase (100%) were increased after PB treatment. The activities of cytochrome b5 and N,N,-dimethyl aniline N-oxide (DAO) were, however, decreased 79% and 47%, respectively. Most of the DME remained unaffected after PM treatment except for the increase in ANH (55%), ACH (56%), and BD (16%). Potassium dichromate administered to rabbits at a dose of 8 mg/kg body weight/day for 5 days resulted in an increase in the activities of ANH (108%), BD (76%), AD (25%), and DAD (49%), while that of cytochrome b5 and DAO were inhibited 81 and 77%, respectively. There was no effect on the activities of cytochrome P-450, ACH, and cytochrome-c-reductase. Chromium, administered to PB-pretreated animals decreased the activities of ANH (41%), ACH (35%), BD (34%), AD (30%), DAD (51%), cytochrome-c-reductase (72%), and DAO (62%). Other enzymes remained unaffected. When administered to PM-pretreated animals, the activities of ANH, BD, AD, and DAD increased 34, 69, 24 and 54%, respectively, whereas activities of cytochrome b5 and DAO were decreased 96 and 68%, respectively. All other DME remained unaffected. PMID:9037263

  11. Microarray Analysis of Differentially-Expressed Genes Encoding CYP450 and Phase II Drug Metabolizing Enzymes in Psoriasis and Melanoma

    PubMed Central

    Sumantran, Venil N.; Mishra, Pratik; Bera, Rakesh; Sudhakar, Natarajan

    2016-01-01

    Cytochrome P450 drug metabolizing enzymes are implicated in personalized medicine for two main reasons. First, inter-individual variability in CYP3A4 expression is a confounding factor during cancer treatment. Second, inhibition or induction of CYP3A4 can trigger adverse drug–drug interactions. However, inflammation can downregulate CYP3A4 and other drug metabolizing enzymes and lead to altered metabolism of drugs and essential vitamins and lipids. Little is known about effects of inflammation on expression of CYP450 genes controlling drug metabolism in the skin. Therefore, we analyzed seven published microarray datasets, and identified differentially-expressed genes in two inflammatory skin diseases (melanoma and psoriasis). We observed opposite patterns of expression of genes regulating metabolism of specific vitamins and lipids in psoriasis and melanoma samples. Thus, genes controlling the turnover of vitamin D (CYP27B1, CYP24A1), vitamin A (ALDH1A3, AKR1B10), and cholesterol (CYP7B1), were up-regulated in psoriasis, whereas melanomas showed downregulation of genes regulating turnover of vitamin A (AKR1C3), and cholesterol (CYP39A1). Genes controlling abnormal keratinocyte differentiation and epidermal barrier function (CYP4F22, SULT2B1) were up-regulated in psoriasis. The up-regulated CYP24A1, CYP4F22, SULT2B1, and CYP7B1 genes are potential drug targets in psoriatic skin. Both disease samples showed diminished drug metabolizing capacity due to downregulation of the CYP1B1 and CYP3A5 genes. However, melanomas showed greater loss of drug metabolizing capacity due to downregulation of the CYP3A4 gene. PMID:26901218

  12. Drug Metabolizing Enzyme and Transporter Gene Variation, Nicotine Metabolism, Prospective Abstinence, and Cigarette Consumption.

    PubMed

    Bergen, Andrew W; Michel, Martha; Nishita, Denise; Krasnow, Ruth; Javitz, Harold S; Conneely, Karen N; Lessov-Schlaggar, Christina N; Hops, Hyman; Zhu, Andy Z X; Baurley, James W; McClure, Jennifer B; Hall, Sharon M; Baker, Timothy B; Conti, David V; Benowitz, Neal L; Lerman, Caryn; Tyndale, Rachel F; Swan, Gary E

    2015-01-01

    The Nicotine Metabolite Ratio (NMR, ratio of trans-3'-hydroxycotinine and cotinine), has previously been associated with CYP2A6 activity, response to smoking cessation treatments, and cigarette consumption. We searched for drug metabolizing enzyme and transporter (DMET) gene variation associated with the NMR and prospective abstinence in 2,946 participants of laboratory studies of nicotine metabolism and of clinical trials of smoking cessation therapies. Stage I was a meta-analysis of the association of 507 common single nucleotide polymorphisms (SNPs) at 173 DMET genes with the NMR in 449 participants of two laboratory studies. Nominally significant associations were identified in ten genes after adjustment for intragenic SNPs; CYP2A6 and two CYP2A6 SNPs attained experiment-wide significance adjusted for correlated SNPs (CYP2A6 PACT=4.1E-7, rs4803381 PACT=4.5E-5, rs1137115, PACT=1.2E-3). Stage II was mega-regression analyses of 10 DMET SNPs with pretreatment NMR and prospective abstinence in up to 2,497 participants from eight trials. rs4803381 and rs1137115 SNPs were associated with pretreatment NMR at genome-wide significance. In post-hoc analyses of CYP2A6 SNPs, we observed nominally significant association with: abstinence in one pharmacotherapy arm; cigarette consumption among all trial participants; and lung cancer in four case:control studies. CYP2A6 minor alleles were associated with reduced NMR, CPD, and lung cancer risk. We confirmed the major role that CYP2A6 plays in nicotine metabolism, and made novel findings with respect to genome-wide significance and associations with CPD, abstinence and lung cancer risk. Additional multivariate analyses with patient variables and genetic modeling will improve prediction of nicotine metabolism, disease risk and smoking cessation treatment prognosis. PMID:26132489

  13. Drug Metabolizing Enzyme and Transporter Gene Variation, Nicotine Metabolism, Prospective Abstinence, and Cigarette Consumption

    PubMed Central

    Bergen, Andrew W.; Michel, Martha; Nishita, Denise; Krasnow, Ruth; Javitz, Harold S.; Conneely, Karen N.; Lessov-Schlaggar, Christina N.; Hops, Hyman; Zhu, Andy Z. X.; Baurley, James W.; McClure, Jennifer B.; Hall, Sharon M.; Baker, Timothy B.; Conti, David V.; Benowitz, Neal L.; Lerman, Caryn; Tyndale, Rachel F.; Swan, Gary E.

    2015-01-01

    The Nicotine Metabolite Ratio (NMR, ratio of trans-3’-hydroxycotinine and cotinine), has previously been associated with CYP2A6 activity, response to smoking cessation treatments, and cigarette consumption. We searched for drug metabolizing enzyme and transporter (DMET) gene variation associated with the NMR and prospective abstinence in 2,946 participants of laboratory studies of nicotine metabolism and of clinical trials of smoking cessation therapies. Stage I was a meta-analysis of the association of 507 common single nucleotide polymorphisms (SNPs) at 173 DMET genes with the NMR in 449 participants of two laboratory studies. Nominally significant associations were identified in ten genes after adjustment for intragenic SNPs; CYP2A6 and two CYP2A6 SNPs attained experiment-wide significance adjusted for correlated SNPs (CYP2A6 PACT=4.1E-7, rs4803381 PACT=4.5E-5, rs1137115, PACT=1.2E-3). Stage II was mega-regression analyses of 10 DMET SNPs with pretreatment NMR and prospective abstinence in up to 2,497 participants from eight trials. rs4803381 and rs1137115 SNPs were associated with pretreatment NMR at genome-wide significance. In post-hoc analyses of CYP2A6 SNPs, we observed nominally significant association with: abstinence in one pharmacotherapy arm; cigarette consumption among all trial participants; and lung cancer in four case:control studies. CYP2A6 minor alleles were associated with reduced NMR, CPD, and lung cancer risk. We confirmed the major role that CYP2A6 plays in nicotine metabolism, and made novel findings with respect to genome-wide significance and associations with CPD, abstinence and lung cancer risk. Additional multivariate analyses with patient variables and genetic modeling will improve prediction of nicotine metabolism, disease risk and smoking cessation treatment prognosis. PMID:26132489

  14. Andrographis paniculata Extract and Andrographolide Modulate the Hepatic Drug Metabolism System and Plasma Tolbutamide Concentrations in Rats

    PubMed Central

    Chen, Haw-Wen; Huang, Chin-Shiu; Liu, Pei-Fen; Li, Chien-Chun; Liu, Cheng-Tzu; Chiang, Jia-Rong; Yao, Hsien-Tsung; Lii, Chong-Kuei

    2013-01-01

    Andrographolide is the most abundant terpenoid of A. paniculata which is used in the treatment of diabetes. In this study, we investigated the effects of A. paniculata extract (APE) and andrographolide on the expression of drug-metabolizing enzymes in rat liver and determined whether modulation of these enzymes changed the pharmacokinetics of tolbutamide. Rats were intragastrically dosed with 2 g/kg/day APE or 50 mg/kg/day andrographolide for 5 days before a dose of 20 mg/kg tolbutamide was given. APE and andrographolide reduced the AUC0–12 h of tolbutamide by 37% and 18%, respectively, compared with that in controls. The protein and mRNA levels and enzyme activities of CYP2C6/11, CYP1A1/2, and CYP3A1/2 were increased by APE and andrographolide. To evaluate whether APE or andrographolide affected the hypoglycemic action of tolbutamide, high-fat diet-induced obese mice were used and treated in the same manner as the rats. APE and andrographolide increased CYP2C6/11 expression and decreased plasma tolbutamide levels. In a glucose tolerance test, however, the hypoglycemic effect of tolbutamide was not changed by APE or andrographolide. These results suggest that APE and andrographolide accelerate the metabolism rate of tolbutamide through increased expression and activity of drug-metabolizing enzymes. APE and andrographolide, however, do not impair the hypoglycemic effect of tolbutamide. PMID:23997806

  15. Drug Metabolizing Enzymes in Type II Diabetes and their Pharmacogenetics During Therapy of Anti-Diabetes Drugs.

    PubMed

    Chakraborty, Chiranjib; Hsu, Minna J; Agoramoorthy, Govindasamy

    2015-01-01

    The type 2 diabetes or T2D mellitus has turn into an epidemic throughout the globe in recent years. Various forms of treatment modalities have been available for patients with T2D with some major classes of approved drugs that include Sulfonylureas, Meglitinides, Biguanides, Thiazolidinedione, Alpha-glucosidase inhibitors, GLP-1 analogs, DPP-4 Inhibitors, and SGLT2 inhibitors. This review focuses on the drug metabolizing enzymes (DME), gene polymorphisms, and inter-individual variability in therapeutics including adverse reaction effects involving Phase-I DME and Phase-II in general. This review also covers some key anti-diabetic drugs with respect to their pharcogenomics. PMID:26652255

  16. Coordinated Regulation of Hepatic Phase I and II Drug-Metabolizing Genes and Transporters using AhR-, CAR-, PXR-, PPARα-, and Nrf2-Null Mice

    PubMed Central

    Aleksunes, Lauren M.

    2012-01-01

    The transcription factors aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor α (PPARα), and nuclear factor erythroid 2-related factor 2 (Nrf2) regulate genes encoding drug-metabolizing enzymes and transporters in livers of mice after chemical activation. However, the specificity of their transcriptional regulation has not been determined systematically in vivo. The purpose of this study was to identify genes encoding drug-metabolizing enzymes and transporters altered by chemical activators in a transcription factor-dependent manner using wild-type and transcription factor-null mice. Chemical activators were administered intraperitoneally to mice once daily for 4 days. Livers were collected 24 h after the final dose, and total RNA was isolated for mRNA quantification of cytochromes P450, NAD(P)H quinone oxidoreductase 1 (Nqo1), aldehyde dehydrogenases (Aldhs), glutathione transferases (Gsts), sulfotransferases (Sults), UDP-glucuronosyltransferases (Ugts), organic anion-transporting polypeptides (Oatps), and multidrug resistance-associated proteins (Mrps). Pharmacological activation of each transcription factor leads to mRNA induction of drug metabolic and transport genes in livers of male and female wild-type mice, but no change in null mice: AhR (Cyp1a2, Nqo1, Aldh7a1, Ugt1a1, Ugt1a6, Ugt1a9, Ugt2b35, Sult5a1, Gstm3, and Mrp4), CAR (Cyp2b10, Aldh1a1, Aldh1a7, Ugt1a1, Ugt2b34, Sult1e1, Sult3a1, Sult5a1, Papps2, Gstt1, Gsta1, Gsta4, Gstm1–4, and Mrp2–4), PXR (Cyp3a11, Ugt1a1, Ugt1a5, Ugt1a9, Gsta1, Gstm1–m3, Oatp1a4, and Mrp3), PPARα (Cyp4a14, Aldh1a1, mGst3, Gstm4, and Mrp4), and Nrf2 (Nqo1, Aldh1a1, Gsta1, Gsta4, Gstm1–m4, mGst3, and Mrp3–4). Taken together, these data reveal transcription factor specificity and overlap in regulating hepatic drug disposition genes by chemical activators. Coordinated regulation of phase I, phase II, and transport genes by

  17. Assessment of drug metabolism enzyme and transporter pharmacogenetics in drug discovery and early development: perspectives of the I-PWG.

    PubMed

    Brian, William; Tremaine, Larry M; Arefayene, Million; de Kanter, Ruben; Evers, Raymond; Guo, Yingying; Kalabus, James; Lin, Wen; Loi, Cho-Ming; Xiao, Guangqing

    2016-04-01

    Genetic variants of drug metabolism enzymes and transporters can result in high pharmacokinetic and pharmacodynamic variability, unwanted characteristics of efficacious and safe drugs. Ideally, the contributions of these enzymes and transporters to drug disposition can be predicted from in vitro experiments and in silico modeling in discovery or early development, and then be utilized during clinical development. Recently, regulatory agencies have provided guidance on the preclinical investigation of pharmacogenetics, for application to clinical drug development. This white paper summarizes the results of an industry survey conducted by the Industry Pharmacogenomics Working Group on current practice and challenges with using in vitro systems and in silico models to understand pharmacogenetic causes of variability in drug disposition. PMID:27045656

  18. Induction of drug-metabolizing enzymes by tricyclic antidepressants in human liver: characterization and partial resolution of cytochromes P-450.

    PubMed Central

    Cresteil, T; Célier, C; Kremers, P; Flinois, J P; Beaune, P; Leroux, J P

    1983-01-01

    Drug-metabolizing enzyme activities were determined in liver microsomes from six kidney-transplant donors, one tricyclic antidepressant-treated and five untreated donors. The tricyclic antidepressant treatment modifies neither the overall cytochrome P-450 content of the liver, nor enzymatic activities of 4-nitroanisole demethylase, aniline hydroxylase, epoxide hydrolase and glutathione S-transferase. Only benzphetamine and ketotifen demethylation and conjugation of bilirubin with UDP-glucuronic acid are markedly augmented (more than two-fold). Separation of the different cytochrome P-450 fractions on a DEAE cellulose column indicates a modification of the elution pattern: the fraction increased by tricyclic antidepressants is responsible for the enhanced monooxygenase activity towards benzopyrene and benzphetamine. PMID:6661349

  19. Predicting Drug Extraction in the Human Gut Wall: Assessing Contributions from Drug Metabolizing Enzymes and Transporter Proteins using Preclinical Models.

    PubMed

    Peters, Sheila Annie; Jones, Christopher R; Ungell, Anna-Lena; Hatley, Oliver J D

    2016-06-01

    Intestinal metabolism can limit oral bioavailability of drugs and increase the risk of drug interactions. It is therefore important to be able to predict and quantify it in drug discovery and early development. In recent years, a plethora of models-in vivo, in situ and in vitro-have been discussed in the literature. The primary objective of this review is to summarize the current knowledge in the quantitative prediction of gut-wall metabolism. As well as discussing the successes of current models for intestinal metabolism, the challenges in the establishment of good preclinical models are highlighted, including species differences in the isoforms; regional abundances and activities of drug metabolizing enzymes; the interplay of enzyme-transporter proteins; and lack of knowledge on enzyme abundances and availability of empirical scaling factors. Due to its broad specificity and high abundance in the intestine, CYP3A is the enzyme that is frequently implicated in human gut metabolism and is therefore the major focus of this review. A strategy to assess the impact of gut wall metabolism on oral bioavailability during drug discovery and early development phases is presented. Current gaps in the mechanistic understanding and the prediction of gut metabolism are highlighted, with suggestions on how they can be overcome in the future. PMID:26895020

  20. The influence of starvation upon hepatic drug metabolism in rats, mice, and guinea pigs.

    NASA Technical Reports Server (NTRS)

    Furner, R. L.; Feller, D. D.

    1971-01-01

    Male rats, mice, and guinea pigs were starved for 1, 2, or 3 days, and the metabolism of ethylmorphine, p-nitroanisole, and aniline was studied. Results suggest that the oxidative enzyme systems studied are not interdependent, and the pathways studied appear to be species dependent.

  1. Urinary metabolites to assess in vivo ontogeny of hepatic drug metabolism in early neonatal life.

    PubMed

    Allegaert, K; Verbesselt, R; Rayyan, M; Debeer, A; de Hoon, J

    2007-05-01

    In addition to size-dependent allometric metabolic activity, most isoenzymes display age-dependent isoenzyme-specific ontogeny. We therefore need probe drugs to describe isoenzyme-specific ontogeny to develop more sophisticated, physiologically based models. We illustrate the feasibility and the relevance of in vivo assessment of hepatic metabolism, based on observations on urinary elimination of paracetamol and tramadol metabolites in neonates. On the basis of the observations on tramadol disposition, we were able to document that O-demethylation phenotypic activity developed sooner when compared with N-demethylation. During repeated administration of intravenous paracetamol, it was documented that, in addition to postmenstrual and postnatal age (PNA), repeated administration also contributed to the urinary excretion of glucuronidated paracetamol. In both probe drugs evaluated, age only in part explained the interindividual variability observed. Urine metabolites to assess in vivo metabolism of drugs routinely administered in neonates likely increase both the feasibility and clinical relevance of studies on in vivo isoenzyme-specific ontogeny in neonates. PMID:17609736

  2. Gallic acid and gallic acid derivatives: effects on drug metabolizing enzymes.

    PubMed

    Ow, Yin-Yin; Stupans, Ieva

    2003-06-01

    Gallic acid and its structurally related compounds are found widely distributed in fruits and plants. Gallic acid, and its catechin derivatives are also present as one of the main phenolic components of both black and green tea. Esters of gallic acid have a diverse range of industrial uses, as antioxidants in food, in cosmetics and in the pharmaceutical industry. In addition, gallic acid is employed as a source material for inks, paints and colour developers. Studies utilising these compounds have found them to possess many potential therapeutic properties including anti-cancer and antimicrobial properties. In this review, studies of the effects of gallic acid, its esters, and gallic acid catechin derivatives on Phase I and Phase II enzymes are examined. Many published reports of the effects of the in vitro effects of gallic acid and its derivatives on drug metabolising enzymes concern effects directly on substrate (generally drug or mutagen) metabolism or indirectly through observed effects in Ames tests. In the case of the Ames test an antimutagenic effect may be observed through inhibition of CYP activation of indirectly acting mutagens and/or by scavenging of metabolically generated mutagenic electrophiles. There has been considerable interest in the in vivo effects of the gallate esters because of their incorporation into foodstuffs as antioxidants and in the catechin gallates with their potential role as chemoprotective agents. Principally an induction of Phase II enzymes has been observed however more recent studies using HepG2 cells and primary cultures of human hepatocytes provide evidence for the overall complexity of actions of individual components versus complex mixtures, such as those in food. Further systematic studies of mechanisms of induction and inhibition of drug metabolising enzymes by this group of compounds are warranted in the light of their distribution and consequent ingestion, current uses and suggested therapeutic potential. However, it

  3. Metabolism of chamaechromone in vitro with human liver microsomes and recombinant human drug-metabolizing enzymes.

    PubMed

    Lou, Yan; Hu, Haihong; Qiu, Yunqing; Zheng, Jinqi; Wang, Linrun; Zhang, Xingguo; Zeng, Su

    2014-04-01

    Chamaechromone is a major component in the dried roots of Stellera chamaejasme with antihepatitis B virus and insecticidal activity. In this study, metabolic profiles of chamaechromone were investigated in human liver microsomes. One monohydroxide and two monoglucuronides of chamaechromone were identified. The enzyme kinetics for both hydroxylation and glucuronidation were fitted to the Michaelis-Menten equation. The hydroxylation of chamaechromone was inhibited by α-naphthoflavone, and predominantly catalyzed by recombinant human cytochrome P450 1A2, whereas the glucuronidation was inhibited by quercetin, 1-naphthol, and fluconazole, and mainly catalyzed by recombinant human UDP-glucuronosyltransferase 1A3, 1A7, 1A9, and 2B7. PMID:24687737

  4. Nuclear receptors in the multidrug resistance through the regulation of drug-metabolizing enzymes and drug transporters

    PubMed Central

    CHEN, Yakun; TANG, Yong; GUO, Changxiong; WANG, Jiuhui; BORAL, Debasish; NIE, Daotai

    2012-01-01

    Chemotherapy is one of the three most common treatment modalities for cancer. However, its efficacy is limited by multidrug resistant cancer cells. Drug metabolizing enzymes (DMEs) and efflux transporters promote the metabolism, elimination, and detoxification of chemotherapeutic agents. Consequently, elevated levels of DMEs and efflux transporters reduce the therapeutic effectiveness of chemotheraputics and, often, lead to treatment failure. Nuclear receptors, especially pregnane X receptor (PXR, NR1I2) and constitutive androstane activated receptor (CAR, NR1I3), are increasingly recognized for their role in xenobiotic metabolism and clearance as well as their role in the development of multidrug resistance (MDR) during chemotherapy. Promiscuous xenobiotic receptors, including PXR and CAR, govern the inducible expressions of a broad spectrum of target genes that encode phase I DMEs, phase II DMEs, and efflux transporters. Recent studies conducted by a number of groups, including ours, have revealed that PXR and CAR play pivotal roles in the development of MDR in various human carcinomas, including prostate, colon, ovarian, and esophageal squamous cell carcinomas. Accordingly, PXR/CAR expression levels and/or activation statuses may predict prognosis and identify the risk of drug resistance in patients subjected to chemotherapy. Further, PXR/CAR antagonists, when used in combination with existing chemotherapeutics that activate PXR/CAR, are feasible and promising options that could be utilized to overcome or, at least, attenuate MDR in cancer cells. PMID:22326308

  5. Distribution of genetic polymorphisms of genes encoding drug metabolizing enzymes & drug transporters - a review with Indian perspective

    PubMed Central

    Umamaheswaran, Gurusamy; Kumar, Dhakchinamoorthi Krishna; Adithan, Chandrasekaran

    2014-01-01

    Phase I and II drug metabolizing enzymes (DME) and drug transporters are involved in the absorption, distribution, metabolism as well as elimination of many therapeutic agents, toxins and various pollutants. Presence of genetic polymorphisms in genes encoding these proteins has been associated with marked inter-individual variability in their activity that could result in variation in drug response, toxicity as well as in disease predisposition. The emergent field pharmacogenetics and pharmacogenomics (PGx) is a promising discipline, as it predicts disease risk, selection of proper medication with regard to response and toxicity, and appropriate drug dosage guidance based on an individual's genetic make-up. Consequently, genetic variations are essential to understand the ethnic differences in disease occurrence, development, prognosis, therapeutic response and toxicity. For that reason, it is necessary to establish the normative frequency of these genes in a particular population before unraveling the genotype-phenotype associations. Although a fair amount of allele frequency data are available in Indian populations, the existing pharmacogenetic data have not been compiled into a database. This review was intended to compile the normative frequency distribution of the variants of genes encoding DMEs (CYP450s, TPMT, GSTs, COMT, SULT1A1, NAT2 and UGTs) and transporter proteins (MDR1, OCT1 and SLCO1B1) with Indian perspective. PMID:24604039

  6. Decrease in the activity of the drug-metabolizing enzymes of rat liver following the administration of tilorone hydrochloride.

    PubMed

    Leeson, G A; Biedenbach, S A; Chan, K Y; Gibson, J P; Wright, G J

    1976-01-01

    Tilorone hydrochloride, 2,7-bias(2-(diethylamino)ethoxy(fluoren-9-one dihydrochloride, has been studied to determine its effect on the drug-metabolizing enzymes of the liver of male Charles River CD strain rats. Single and multiple doses of tilorone-HCl, 100 mg/kg/day po, were used. Most experiments were performed 24 hr after the last dose, except for a study 5 hr after dosing, and those in which the duration of effects of tilorone hydrochloride were determined. The hexobarbital sleeping time was prolonged after both single doses and four doses of tilorone hydrochloride. The 4-dose regimen prolonged the zoxazolamine paralysis time but the single dose did not. A decrease in microsomal protein was observed after the single- and 4-dose regimens but not after 21 daily doses of tilorone-HCl. Cytochrome P-450 content of microsomes was decreased by the single doses, 100 and 250 mg/kg po, and by 4 and 21 doses of 100 mg/kg/day po. Activities of aminopyrine demethylase and hexobarbital oxidase also were decreased by the above regimens, but the activity of hexobarbital oxidase was affected more markedly. Electron micrographs of rat liver, after treatment with tilorone-HCl, 100 mg/kg/day for 21 days, revealed many membranous structures in the form of whorls. PMID:6227

  7. Potential risks resulting from fruit/vegetable-drug interactions: effects on drug-metabolizing enzymes and drug transporters.

    PubMed

    Rodríguez-Fragoso, Lourdes; Martínez-Arismendi, José Luis; Orozco-Bustos, Danae; Reyes-Esparza, Jorge; Torres, Eliseo; Burchiel, Scott W

    2011-05-01

    It has been well established that complex mixtures of phytochemicals in fruits and vegetables can be beneficial for human health. Moreover, it is becoming increasingly apparent that phytochemicals can influence the pharmacological activity of drugs by modifying their absorption characteristics through interactions with drug transporters as well as drug-metabolizing enzyme systems. Such effects are more likely to occur in the intestine and liver, where high concentrations of phytochemicals may occur. Alterations in cytochrome P450 and other enzyme activities may influence the fate of drugs subject to extensive first-pass metabolism. Although numerous studies of nutrient-drug interactions have been published and systematic reviews and meta-analyses of these studies are available, no generalizations on the effect of nutrient-drug interactions on drug bioavailability are currently available. Several publications have highlighted the unintended consequences of the combined use of nutrients and drugs. Many phytochemicals have been shown to have pharmacokinetic interactions with drugs. The present review is limited to commonly consumed fruits and vegetables with significant beneficial effects as nutrients and components in folk medicine. Here, we discuss the phytochemistry and pharmacokinetic interactions of the following fruit and vegetables: grapefruit, orange, tangerine, grapes, cranberry, pomegranate, mango, guava, black raspberry, black mulberry, apple, broccoli, cauliflower, watercress, spinach, tomato, carrot, and avocado. We conclude that our knowledge of the potential risk of nutrient-drug interactions is still limited. Therefore, efforts to elucidate potential risks resulting from food-drug interactions should be intensified in order to prevent undesired and harmful clinical consequences. PMID:22417366

  8. A pilot study of leukocyte expression patterns for drug metabolizing enzyme and transporter transcripts in autoimmune glomerulonephritis

    PubMed Central

    Joy, Melanie S.; Roberts, Brittney V.; Wang, Jinzhao; Hu, Yichun; Hogan, Susan L.; Falk, Ronald J.

    2014-01-01

    Objective: Leukocyte mRNA expression patterns of drug metabolizing enzyme genes and transporter genes that are relevant for the disposition of cyclophosphamide and mycophenolate were studied. The relationships between expression and patient-level data and pharmacokinetics were evaluated. Methods: The study included patients with glomerulonephritis secondary to lupus nephritis (SLE, n = 36), small vessel vasculitis (SVV, n = 35), healthy controls (HC, n = 10), and disease controls (VC, n = 5; LC, n = 5). Transcript assays targeted metabolizing enzymes (UGT1A7, UGT1A9, UGT2B7, CYP3A4, CYP2C9, CYP2B6) and transporters (ABCB1, ABCC2, ABCG2, SLCO1A2). Genotyping for specific variants was conducted. Group transcript fold-changes were evaluated. Patient level data was evaluated for transcript fold-change and disease, treatment, gender, race, and genotype. Results: Significant differences were noted in expression of UGT1A7, ABCB1, and ABCC2; for UGT1A7, SVV (0.17 ± 0.42; p < 0.05) and SLE (0.03 ± 0.1; p < 0.05) groups had lower expression than HC (0.79 ± 2.02). For ABCB1, SLE had a lower expression (0.33 ± 0.21; p < 0.05) than HCs (1 ± 0.82). For ABCG2, SVV group had a lower expression (0.17 ± 0.14; p < 0.05) than HCs (1 ± 1.82). Differences in expression of ABCC2 approached statistical significance with VC patients (2.02 ± 1.13) exhibiting higher expression than SVV patients (1.06 ± 1.11; p = 0.05). The relationships between transcript expression and patient-level data demonstrated; ABCC2 expression was different by race (1.26 ± 1.82 Caucasian versus 1.37 ± 0.86 non-Caucasian; p = 0.049) and CYP2B6 expression was different by treatment (2.07 ± 2.94 cyclophosphamide versus 0.45 ± 0.5 mycophenolate; p = 0.01). Conclusions: The current study showed differential expression of drug metabolizing enzyme and transporter transcripts and contributes to the literature on transcript expression of drug transporters in

  9. The impact of genetic polymorphisms of drug metabolizing enzymes on the pharmacodynamics of clopidogrel under steady state conditions.

    PubMed

    Nakkam, Nontaya; Tiamkao, Somsak; Kanjanawart, Sirimas; Tiamkao, Siriporn; Vannaprasaht, Suda; Tassaneeyakul, Wongwiwat; Tassaneeyakul, Wichittra

    2015-08-01

    Clopidogrel is an antiplatelet drug that requires biotransformation steps to its active metabolite via cytochromes P450 (CYP), particularly CYP2C19 and CYP3A5 as well as paraoxonase-1 (PON1). The impact of CYP3A5 and PON1 genetic polymorphisms on the response of this drug is unclear. This study aimed to elucidate the degree of genetic polymorphisms of key drug metabolizing enzymes on the antiplatelet effect of clopidogrel. Thirty-five healthy subjects were treated with 75 mg/day clopidogrel for 7 days and serial blood samples were collected for measurement of antiplatelet effect using whole blood impedance aggregometry and VerifyNow(®) P2Y12 methods. The areas under the antiplatelet effect-time curves, maximal and minimal antiplatelet effects of clopidogrel obtained from both methods were significantly different among subjects with different CYP2C19 genotypes. In contrast, these pharmacodymamic parameters measured by both methods of subjects with different PON1 or CYP3A5 genotypes were not significantly different. Among the heterozygous CYP2C19*2 subjects, all pharmacodynamic parameters measured by whole blood impedance aggregometry were significantly different between subjects with different CYP3A5*3 genotypes. Our data suggests that CYP2C19 genetic polymorphism play a major role in the clopidogrel response, however, the impact of CYP3A5 genetic polymorphism, may be pronounced in the subjects who carried the loss-functional allele of CYP2C19. PMID:26099919

  10. An Enhanced In Vivo Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) Model for Quantification of Drug Metabolism Enzymes*

    PubMed Central

    MacLeod, A. Kenneth; Fallon, Padraic G.; Sharp, Sheila; Henderson, Colin J.; Wolf, C. Roland; Huang, Jeffrey T.-J.

    2015-01-01

    Many of the enzymes involved in xenobiotic metabolism are maintained at a low basal level and are only synthesized in response to activation of upstream sensor/effector proteins. This induction can have implications in a variety of contexts, particularly during the study of the pharmacokinetics, pharmacodynamics, and drug–drug interaction profile of a candidate therapeutic compound. Previously, we combined in vivo SILAC material with a targeted high resolution single ion monitoring (tHR/SIM) LC-MS/MS approach for quantification of 197 peptide pairs, representing 51 drug metabolism enzymes (DME), in mouse liver. However, as important enzymes (for example, cytochromes P450 (Cyp) of the 1a and 2b subfamilies) are maintained at low or undetectable levels in the liver of unstimulated metabolically labeled mice, quantification of these proteins was unreliable. In the present study, we induced DME expression in labeled mice through synchronous ligand-mediated activation of multiple upstream nuclear receptors, thereby enhancing signals for proteins including Cyps 1a, 2a, 2b, 2c, and 3a. With this enhancement, 115 unique, lysine-containing, Cyp-derived peptides were detected in the liver of a single animal, as opposed to 56 in a pooled sample from three uninduced animals. A total of 386 peptide pairs were quantified by tHR/SIM, representing 68 Phase I, 30 Phase II, and eight control proteins. This method was employed to quantify changes in DME expression in the hepatic cytochrome P450 reductase null (HRN) mouse. We observed compensatory induction of several enzymes, including Cyps 2b10, 2c29, 2c37, 2c54, 2c55, 2e1, 3a11, and 3a13, carboxylesterase (Ces) 2a, and glutathione S-transferases (Gst) m2 and m3, along with down-regulation of hydroxysteroid dehydrogenases (Hsd) 11b1 and 17b6. Using DME-enhanced in vivo SILAC material with tHR/SIM, therefore, permits the robust analysis of multiple DME of importance to xenobiotic metabolism, with improved utility for the study of

  11. Pharmacokinetics and pharmacodynamics of phase II drug metabolizing/antioxidant enzymes gene response by anticancer agent sulforaphane in rat lymphocytes.

    PubMed

    Wang, Hu; Khor, Tin Oo; Yang, Qian; Huang, Ying; Wu, Tien-Yuan; Saw, Constance Lay-Lay; Lin, Wen; Androulakis, Ioannis P; Kong, Ah-Ng Tony

    2012-10-01

    This study assesses the pharmacokinetics (PK) and pharmacodynamics (PD) of Nrf2-mediated increased expression of phase II drug metabolizing enzymes (DME) and antioxidant enzymes which represents an important component of cancer chemoprevention in rat lymphocytes following intravenous (iv) administration of an anticancer phytochemical sulforaphane (SFN). SFN was administered intravenously to four groups of male Sprague-Dawley JVC rats each group comprising four animals. Blood samples were drawn at selected time points. Plasma were obtained from half of each of the blood samples and analyzed using a validated LC-MS/MS method. Lymphocytes were collected from the remaining blood samples using Ficoll-Paque Plus centrifuge medium. Lymphocyte RNAs were extracted and converted to cDNA, quantitative real-time PCR analyses were performed, and fold changes were calculated against those at time zero for the relative expression of Nrf2-target genes of phase II DME/antioxidant enzymes. PK-PD modeling was conducted based on Jusko's indirect response model (IDR) using GastroPlus and bootstrap method. SFN plasma concentration declined biexponentially and the pharmacokinetic parameters were generated. Rat lymphocyte mRNA expression levels showed no change for GSTM1, SOD, NF-κB, UGT1A1, or UGT1A6. Moderate increases (2-5-fold) over the time zero were seen for HO-1, Nrf2, and NQO1, and significant increases (>5-fold) for GSTT1, GPx1, and Maf. PK-PD analyses using GastroPlus and the bootstrap method provided reasonable fitting for the PK and PD profiles and parameter estimates. Our present study shows that SFN could induce Nrf2-mediated phase II DME/antioxidant mRNA expression for NQO1, GSTT1, Nrf2, GPx, Maf, and HO-1 in rat lymphocytes after iv administration, suggesting that Nrf2-mediated mRNA expression in lymphocytes may serve as surrogate biomarkers. The PK-PD IDR model simultaneously linking the plasma concentrations of SFN and the PD response of lymphocyte mRNA expression is

  12. Hepatic cytochrome P450 3A drug metabolism is reduced in cancer patients who have an acute-phase response

    PubMed Central

    Rivory, L P; Slaviero, K A; Clarke, S J

    2002-01-01

    Inflammatory disease states (infection, arthritis) are associated with reduced drug oxidation by the cytochrome P450 3A system. Many chemotherapy agents are metabolised through this pathway, and disease may therefore influence inter-individual differences in drug pharmacokinetics. The purpose of this study was to assess cytochrome P450 3A function in patients with advanced cancer, and its relation to the acute-phase response. We evaluated hepatic cytochrome P450 3A function in 40 patients with advanced cancer using the erythromycin breath test. Both the traditional C20min measure and the recently proposed 1/TMAX values were estimated. The marker of acute-phase response, C-reactive protein and the pro-inflammatory cytokines IL-6, IL-1β, TNFα and IL-8 were measured in serum or plasma at baseline. Cancer patients with an acute phase response (C-reactive protein >10 mg l−1, n=26) had reduced metabolism as measured with the erythromycin breath test 1/TMAX (Kruskal–Wallis Anova, P=0.0062) as compared to controls (C-reactive protein ⩽10 mg l−1, n=14). Indeed, metabolism was significantly associated with C-reactive protein over the whole concentration range of this acute-phase marker (r=−0.64, Spearman Rank Correlation, P<0.00001). C-reactive protein serum levels were significantly correlated with those of IL-6 (Spearman coefficient=0.58, P<0.0003). The reduction in cytochrome P450 3A function with acute-phase reaction was independent of the tumour type and C-reactive protein elevation was associated with poor performance status. This indicates that the sub-group of cancer patients with significant acute-phase response have compromised drug metabolism, which may have implications for the safety of chemotherapy in this population. British Journal of Cancer (2002) 87, 277–280. doi:10.1038/sj.bjc.6600448 www.bjcancer.com © 2002 Cancer Research UK PMID:12177794

  13. Effect of Intestinal Flora on Protein Expression of Drug-Metabolizing Enzymes and Transporters in the Liver and Kidney of Germ-Free and Antibiotics-Treated Mice.

    PubMed

    Kuno, Takuya; Hirayama-Kurogi, Mio; Ito, Shingo; Ohtsuki, Sumio

    2016-08-01

    Dysbiosis (alteration of intestinal flora) is associated with various host physiologies, including diseases. The purpose of this study was to clarify the effect of dysbiosis on protein expression levels in mouse liver and kidney by quantitative proteomic analysis, focusing in particular on drug-metabolizing enzymes and transporters in order to investigate the potential impact of dysbiosis on drug pharmacokinetics. Germ-free (GF) mice and antibiotics-treated mice were used as dysbiosis models. Expression levels of 825 and 357 proteins were significantly changed in the liver and kidney, respectively, of GF mice (vs specific-pathogen-free mice), while 306 and 178 proteins, respectively, were changed in antibiotics-treated mice (vs vehicle controls). Among them, 52 and 16 drug-metabolizing enzyme and transporter proteins were significantly changed in the liver and kidney, respectively, of GF mice, while 25 and 8, respectively were changed in antibiotics-treated mice. Expression of mitochondrial proteins was also changed in the liver and kidney of both model mice. In GF mice, Oatp1a1 was decreased in both the liver and kidney, while Sult1a1 and two Cyp enzymes were increased and Gstp1, four Cyp enzymes, three Ces enzymes, Bcrp1, and Oct1 were decreased in the liver. In antibiotics-treated mice, Cyp51a1 was increased and three Cyp enzymes, Bcrp1, and Bsep were decreased in the liver. Notably, the expression of Cyp2b10 and Cyp3a11 was greatly decreased in the liver of both models. Cyp2b activity in the liver microsomal fraction was also decreased. Our results indicate that dysbiosis changes the protein expression of multiple drug-metabolizing enzymes and transporters in the liver and kidney and may alter pharmacokinetics in the host. PMID:27376980

  14. Xenobiotic Metabolism: The Effect of Acute Kidney Injury on Non-Renal Drug Clearance and Hepatic Drug Metabolism

    PubMed Central

    Dixon, John; Lane, Katie; MacPhee, Iain; Philips, Barbara

    2014-01-01

    Acute kidney injury (AKI) is a common complication of critical illness, and evidence is emerging that suggests AKI disrupts the function of other organs. It is a recognized phenomenon that patients with chronic kidney disease (CKD) have reduced hepatic metabolism of drugs, via the cytochrome P450 (CYP) enzyme group, and drug dosing guidelines in AKI are often extrapolated from data obtained from patients with CKD. This approach, however, is flawed because several confounding factors exist in AKI. The data from animal studies investigating the effects of AKI on CYP activity are conflicting, although the results of the majority do suggest that AKI impairs hepatic CYP activity. More recently, human study data have also demonstrated decreased CYP activity associated with AKI, in particular the CYP3A subtypes. Furthermore, preliminary data suggest that patients expressing the functional allele variant CYP3A5*1 may be protected from the deleterious effects of AKI when compared with patients homozygous for the variant CYP3A5*3, which codes for a non-functional protein. In conclusion, there is a need to individualize drug prescribing, particularly for the more sick and vulnerable patients, but this needs to be explored in greater depth. PMID:24531139

  15. Stability of drug metabolizing enzymes during the incubation conditions of the liver microsomal assay with non-induced and induced mouse liver S-9 fractions.

    PubMed

    Paolini, M; Tonelli, F; Bauer, C; Corsi, C; Bronzetti, G

    1987-09-01

    The purpose of this work was to study the relative activities and stabilities of phase-I and phase-II drug metabolizing enzymes in incubation mixtures used in vitro genotoxicity testing in order to optimize the conditions of the assay, increase sensitivity and eliminate false negative results. Cytochrome P-450, NADPH-cytochrome P-450 (cytochrome c) reductase activity and various phase-I and phase-II enzyme activities of the drug-metabolizing system were determined in incubation mixtures used in liver microsomal assays. The behaviour of aminopyrine N-demethylase and p-nitroanisole O-demethylase activities as phase-I markers have been reported previously. Other activities measured were glutathione S-transferase, glutathione S-epoxide transferase and epoxide hydrase, and lipid peroxidation (LP) was determined. The experiments were carried out on liver S9 fractions derived from non-induced mice or mice induced with sodium phenobarbital (PB), and/or beta-naphthoflavone (beta-NF). The phase-II enzymes were much more stable (70-90% residual activity) than phase-I enzyme activities (35-60%) in all conditions tested. The residual cytochrome P-450 was approximately 70% stable and the remaining activity of NADPH-cytochrome c-reductase about 80%, indicating that this latter enzyme does not limit the rate of the monoxygenase system in these conditions. Phase-II enzymes were induced to a smaller extent (about 2 times) than in phase-I enzymes (5-6 times) by beta-NF + PB. NADPH-cytochrome c-reductase behaved as phase-II enzymes in this respect as well as for stability. LP was appreciably higher in non-induced than in induced animals. Treatment with the beta-NF + PB mixture, however, showed that induced enzymes were more stable than those obtained by simple induction with either beta-NF or PB alone. These results lead to the conclusion that prolonged incubation times in mutagenicity assays are unnecessary when considering the relative stabilities of the various phase-I and phase

  16. Drug metabolism and chemosensitization. Nitroimidazoles as inhibitors of drug metabolism.

    PubMed

    Workman, P; Twentyman, P R; Lee, F Y; Walton, M I

    1983-03-01

    The nitroimidazole misonidazole (MISO) and related compounds have been shown to enhance the response of tumours to cytotoxic agents, and often to improve their therapeutic indices. Previous experiments suggested inhibition of cytotoxic drug metabolism as a mechanism. We have now investigated the effects of MISO and related compounds on drug metabolism in mice, and the results can be summarised as follows. (1) MISO and related compounds inhibit drug-metabolising enzymes, as measured by pentobarbitone sleep-time and zoxazolamine paralysis-time. (2) Enzyme inhibition is primarily dependent on lipophilicity, with maximum inhibition exhibited by the most active chemosensitizers. (3) MISO significantly slowed the clearance of pentobarbitone, aminopyrine and the cytotoxic agent chlorambucil, but had no effect on renal function or protein binding. These data support the view that inhibition of cytotoxic drug metabolism may be an important factor in chemosensitization. PMID:6838633

  17. Drug metabolism alterations in nonalcoholic fatty liver disease

    PubMed Central

    Merrell, Matthew D.; Cherrington, Nathan J.

    2013-01-01

    Drug-metabolizing enzymes play a vital role in the elimination of the majority of therapeutic drugs. The major organ involved in drug metabolism is the liver. Chronic liver diseases have been identified as a potential source of significant interindividual variation in metabolism. Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the United States, affecting between 60 and 90 million Americans, yet the vast majority of NAFLD patients are undiagnosed. NAFLD encompasses a spectrum of pathologies, ranging from steatosis to nonalcoholic steatohepatitis and fibrosis. Numerous animal studies have investigated the effects of NAFLD on hepatic gene expression, observing significant alterations in mRNA, protein, and activity levels. Information on the effects of NAFLD in human patients is limited, though several significant investigations have recently been published. Significant alterations in the activity of drug-metabolizing enzymes may affect the clearance of therapeutic drugs, with the potential to result in adverse drug reactions. With the enormous prevalence of NAFLD, it is conceivable that every drug currently on the market is being given to patients with NAFLD. The current review is intended to present the results from both animal models and human patients, summarizing the observed alterations in the expression and activity of the phase I and II drug-metabolizing enzymes. PMID:21612324

  18. Going Beyond Common Drug Metabolizing Enzymes: Case Studies of Biotransformation Involving Aldehyde Oxidase, γ-Glutamyl Transpeptidase, Cathepsin B, Flavin-Containing Monooxygenase, and ADP-Ribosyltransferase.

    PubMed

    Fan, Peter W; Zhang, Donglu; Halladay, Jason S; Driscoll, James P; Khojasteh, S Cyrus

    2016-08-01

    The significant roles that cytochrome P450 (P450) and UDP-glucuronosyl transferase (UGT) enzymes play in drug discovery cannot be ignored, and these enzyme systems are commonly examined during drug optimization using liver microsomes or hepatocytes. At the same time, other drug-metabolizing enzymes have a role in the metabolism of drugs and can lead to challenges in drug optimization that could be mitigated if the contributions of these enzymes were better understood. We present examples (mostly from Genentech) of five different non-P450 and non-UGT enzymes that contribute to the metabolic clearance or bioactivation of drugs and drug candidates. Aldehyde oxidase mediates a unique amide hydrolysis of GDC-0834 (N-[3-[6-[4-[(2R)-1,4-dimethyl-3-oxopiperazin-2-yl]anilino]-4-methyl-5-oxopyrazin-2-yl]-2-methylphenyl]-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxamide), leading to high clearance of the drug. Likewise, the rodent-specific ribose conjugation by ADP-ribosyltransferase leads to high clearance of an interleukin-2-inducible T-cell kinase inhibitor. Metabolic reactions by flavin-containing monooxygenases (FMO) are easily mistaken for P450-mediated metabolism such as oxidative defluorination of 4-fluoro-N-methylaniline by FMO. Gamma-glutamyl transpeptidase is involved in the initial hydrolysis of glutathione metabolites, leading to formation of proximate toxins and nephrotoxicity, as is observed with cisplatin in the clinic, or renal toxicity, as is observed with efavirenz in rodents. Finally, cathepsin B is a lysosomal enzyme that is highly expressed in human tumors and has been targeted to release potent cytotoxins, as in the case of brentuximab vedotin. These examples of non-P450- and non-UGT-mediated metabolism show that a more complete understanding of drug metabolizing enzymes allows for better insight into the fate of drugs and improved design strategies of molecules in drug discovery. PMID:27117704

  19. Differences in the drug-metabolizing enzyme activities among fish and bivalves living in waters near industrial and non-industrial areas

    SciTech Connect

    Oshima, Y.; Kobayashi, K.; Hidaka, C.; Izu, S.; Imada, N. )

    1994-07-01

    Fish and shellfishes, living in coastal areas receiving agricultural, industrial and domestic wastewaters, have been exposed to various chemicals. Identifing the various harmful chemicals in the environments and accumulated in aquatic organisms is difficult. Even if concentrations of pollutants are low so that no mortality of fish and shellfishes occurs, the pollutants may affect the biochemistry and physiology of aquatic organisms. Activities of some drug-metabolizing enzymes, especially the cytochrome P-450 dependent monooxygenase (MO) in fish livers, increase when fish are exposed to environmental pollutants such as polycyclic aromatic hydrocarbons, halogenated organic chemicals. However, most studies have been done on the field evaluation only by MO induction in fish as a monitor for marine pollution with crude-oil and halogenated organic compounds, without regard for other chemicals. In a previous paper, the activity of benzo(a)pyrene hydroxylase (AHH) was induced by 22 times at 2-wk, although the cytochrome P-450 content increased only twice. Activity of phenol-sulfate transferase in the mid-gut gland of short-necked clam was induced by exposure to some phenolic compounds, especially pentachlorophenol (PCP), resulting in the increase of the enzyme activity by approximately 7 times the control after 5 wk exposure. Induced activity was maintained at least for 3 wk, even after the clam had been transferred to running clean sea water, although PCP accumulated in its body is rapidly excreted. Although the activity of this enzyme in the clam is easily induced by exposure to phenols, the induction of this enzyme activity in fish is very low as compared with that of clam. This paper examines the activities of drug-metabolizing enzymes of fish and bivalves living in waters near industrial and non-industrial areas to elucidate the applicability of the sulfate transferase activity in bivalves as a monitor for marine pollution, as well as the MO activity in fish.

  20. The Effect of Yokukansan, a Traditional Herbal Preparation Used for the Behavioral and Psychological Symptoms of Dementia, on the Drug-Metabolizing Enzyme Activities in Healthy Male Volunteers.

    PubMed

    Soraoka, Hiromi; Oniki, Kentaro; Matsuda, Kazuki; Ono, Tatsumasa; Taharazako, Kosuke; Uchiyashiki, Yoshihiro; Kamihashi, Ryoko; Kita, Ayana; Takashima, Ayaka; Nakagawa, Kazuko; Yasui-Furukori, Norio; Kadowaki, Daisuke; Miyata, Keishi; Saruwatari, Junji

    2016-01-01

    The concomitant use of herb and prescription medications is increasing globally. Herb-drug interactions are therefore a clinically important problem. Yokukansan (YKS), a Japanese traditional herbal medicine, is one of the most frequently used herbal medicines. It is effective for treating the behavioral and psychological symptoms of dementia. We investigated the potential effects of YKS on drug-metabolizing enzyme activities in humans. An open-label repeat-dose study was conducted in 26 healthy Japanese male volunteers (age: 22.7±2.3 years) with no history of smoking. An 8-h urine sample was collected after a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan before and after the administration of YKS (2.5 g, twice a day for 1 week). The activities of cytochrome P450 (CYP) 1A2, CYP2D6, CYP3A, xanthine oxidase (XO) and N-acetyltransferase 2 (NAT2) were assessed based on the urinary metabolic indices of caffeine and dextromethorphan, and the urinary excretion ratio of 6β-hydroxycortisol to cortisol. There were no statistically significant differences in the activities of the examined enzymes before or after the 7-d administration of YKS. Although further studies assessing the influence of YKS on the pharmacokinetics and pharmacodynamics of the substrates of the drug-metabolizing enzymes are needed to verify the present results, YKS is unlikely that a pharmacokinetic interaction will occur with concomitantly administered medications that are predominantly metabolized by the CYP1A2, CYP2D6, CYP3A, XO and NAT2. PMID:27582327

  1. Up-regulation of drug-metabolizing enzyme genes in layered co-culture of a human liver cell line and endothelial cells.

    PubMed

    Ohno, Maki; Motojima, Kiyoto; Okano, Teruo; Taniguchi, Akiyoshi

    2008-11-01

    Primary human hepatocytes are used extensively to study drug-metabolizing enzymes such as the cytochrome P450 (CYP) enzymes. However, the activities of these enzymes decrease rapidly during culture. In the present study, using a thermo-responsive culture dish, layered co-culture was achieved by placing a bovine pulmonary artery endothelial cell (BPAEC) sheet onto the human hepatoma cell line HepG2. In the BPAEC/HepG2 layered co-culture system, real-time polymerase chain reaction analysis showed that the expression levels of various CYP enzymes were more than 10 times greater 21 days after layering than with a HepG2 monolayer. The expression levels of CYP1B1, CYP2C9, CYP2E1, and CYP3A4 were up-regulated in a time-dependent manner, gradually increasing from day 10 after layering, and continuing to increase until at least day 21. The gene expression levels of the various CYP enzymes were almost identical to that of human liver. These results suggest that our layered co-culture system enhances the function of HepG2 cells and that our BPAEC/HepG2 layered co-culture system can serve as a useful model for the in vitro evaluation of CYP regulation. PMID:18847370

  2. Pharmacogenetics of drug metabolizing enzymes in the United Kingdom population: review of current knowledge and comparison with selected European populations.

    PubMed

    Daly, Ann K

    2015-09-01

    Data on frequency of pharmacogenetic polymorphisms in the UK population are limited. However, availability of whole genome sequencing data on 94 UK controls of European ethnicity from the 1000 genomes project together with similar data on other populations provides a valuable new source of data in this area and allows direct comparison of allele frequencies with those for other European populations. The ethnic diversity of the UK population also needs to be considered, and 1000 genomes includes data on South Asians, the most common ethnic group in the UK after White Europeans. Allele frequencies for polymorphisms in genes relevant to phase I and phase II drug metabolism for UK, Finnish, Spanish and South Asian populations were obtained from the literature and 1000 genomes. Generally there was good agreement between the literature and 1000 genomes reports. CYP2D6*4, the most common CYP2D6 poor metabolizer allele among Europeans, appears more common in the UK than in Spain and Finland, whereas, as suggested previously, CYP2C19*2 and CYP2C9*2 appear more common in Finland and Spain, respectively, than in the UK. South Asians show low frequencies of CYP2C9*2 and CYP2C19*17 but higher frequencies of CYP2C19*2 compared with UK residents of European ethnicity. Though personalizing drug treatment on the basis of individual genotype rather than ethnicity may be more appropriate, differences in allele frequencies across continents should be considered when designing clinical trials of new drugs. PMID:25803091

  3. Summary of Information on the Effects of Ionizing and Non-ionizing Radiation on Cytochrome P450 and Other Drug Metabolizing Enzymes and Transporters

    PubMed Central

    Rendic, Slobodan; Guengerich, F. Peter

    2014-01-01

    The present paper is an update of data on the effects of ionizing radiation (γ-rays, X-rays, high energy UV, fast neutron) caused by environmental pollution or clinical treatments and the effects of non-ionizing radiation (low energy UV) on the expression and/or activity of drug metabolism (e.g., cytochrome P450,, glutathione transferase), enzymes involved in oxidative stress (e.g., peroxidases, catalase,, aconitase, superoxide dismutase), and transporters. The data are presented in tabular form (Tables 1–3) and are a continuation of previously published summaries on the effects of drugs and other chemicals on cytochrome P450 enzymes (Rendic, S.; Di Carlo, F. Drug Metab. Rev., 1997, 29 (1–2), 413–580, Rendic, S. Drug Metab. Rev., 2002, 34 (1–2), 83–448) and of the data on the effects of diseases and environmental factors on the expression and/or activity of human cytochrome P450 enzymes and transporters (Guengerich, F.P.; Rendic, S. Curr. Drug Metab., 2010, 11(1), 1–3, Rendic, S.; Guengerich, F.P. Curr. Drug Metab., 2010, 11 (1), 4–84). The collective information is as presented by the cited author(s) in cases where several references are cited the latest published information is included. Remarks and conclusions suggesting clinically important impacts are highlighted, followed by discussion of the major findings. The searchable database is available as an Excel file (for information about file availability contact the corresponding author). PMID:22571481

  4. COMPARISON OF IN VITRO METHODS AND THE IN VIVO METABOLISM OF LINDANE FOR ASSESSING THE EFFECTS OF REPEATED ADMINISTRATION OF ETHANOL ON HEPATIC DRUG METABOLISM

    EPA Science Inventory

    In vitro methods of assessing alterations in drug metabolism and the measurement of lindane metabolites in urine were compared for their ability to determine the influence of ethanol on drug metabolism. Ethanol was administered to young adult female rats daily for seven days at d...

  5. Structure-Activity Relationship and Substrate-Dependent Phenomena in Effects of Ginsenosides on Activities of Drug-Metabolizing P450 Enzymes

    PubMed Central

    Hao, Miao; Zhao, Yuqing; Chen, Peizhan; Huang, He; Liu, Hong; Jiang, Hualiang; Zhang, Ruiwen; Wang, Hui

    2008-01-01

    Ginseng, a traditional herbal medicine, may interact with several co-administered drugs in clinical settings, and ginsenosides, the major active components of ginseng, may be responsible for these ginseng-drug interactions (GDIs). Results from previous studies on ginsenosides' effects on human drug-metabolizing P450 enzymes are inconsistent and confusing. Herein, we first evaluated the inhibitory effects of fifteen ginsenosides and sapogenins on human CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 enzymes by using commercially available fluorescent probes. The structure-activity relationship of their effects on the P450s was also explored and a pharmacophore model was established for CYP3A4. Moreover, substrate-dependent phenomena were found in ginsenosides' effects on CYP3A4 when another fluorescent probe was used, and were further confirmed in tests with conventional drug probes and human liver microsomes. These substrate-dependent effects of the ginsenosides may provide an explanation for the inconsistent results obtained in previous GDI reports. PMID:18628990

  6. Emerging roles for brain drug-metabolizing cytochrome P450 enzymes in neuropsychiatric conditions and responses to drugs.

    PubMed

    Toselli, Francesca; Dodd, Peter R; Gillam, Elizabeth M J

    2016-08-01

    P450s in the human brain were originally considered unlikely to contribute significantly to the clearance of drugs and other xenobiotic chemicals, since their overall expression was a small fraction of that found in the liver. However, it is now recognized that P450s play substantial roles in the metabolism of both exogenous and endogenous chemicals in the brain, but in a highly cell type- and region-specific manner, in line with the greater functional heterogeneity of the brain compared to the liver. Studies of brain P450 expression and the characterization of the catalytic activity of specific forms expressed as recombinant enzymes have suggested possible roles for xenobiotic-metabolizing P450s in the brain. It is now possible to confirm these roles through the use of intracerebroventricular administration of selective P450 inhibitors in animal models, coupled with brain sampling techniques to measure drug concentrations in vivo, and modern neuroimaging techniques. The purpose of this review is to discuss the evidence behind the functional importance of P450s from the "xenobiotic-metabolizing" families, CYP1, CYP2 and CYP3 in the brain. Approaches used to define the quantitative and qualitative significance of these P450s in determining tissue-specific levels of xenobiotics in brain will be considered. Finally, the possible roles of these enzymes in brain biochemistry will be examined in light of the demonstrated activity of these enzymes in vitro and the association of particular P450 forms with disease states. PMID:27498925

  7. Evolution of a Major Drug Metabolizing Enzyme Defect in the Domestic Cat and Other Felidae: Phylogenetic Timing and the Role of Hypercarnivory

    PubMed Central

    Shrestha, Binu; Reed, J. Michael; Starks, Philip T.; Kaufman, Gretchen E.; Goldstone, Jared V.; Roelke, Melody E.; O'Brien, Stephen J.; Koepfli, Klaus-Peter; Frank, Laurence G.; Court, Michael H.

    2011-01-01

    The domestic cat (Felis catus) shows remarkable sensitivity to the adverse effects of phenolic drugs, including acetaminophen and aspirin, as well as structurally-related toxicants found in the diet and environment. This idiosyncrasy results from pseudogenization of the gene encoding UDP-glucuronosyltransferase (UGT) 1A6, the major species-conserved phenol detoxification enzyme. Here, we established the phylogenetic timing of disruptive UGT1A6 mutations and explored the hypothesis that gene inactivation in cats was enabled by minimal exposure to plant-derived toxicants. Fixation of the UGT1A6 pseudogene was estimated to have occurred between 35 and 11 million years ago with all extant Felidae having dysfunctional UGT1A6. Out of 22 additional taxa sampled, representative of most Carnivora families, only brown hyena (Parahyaena brunnea) and northern elephant seal (Mirounga angustirostris) showed inactivating UGT1A6 mutations. A comprehensive literature review of the natural diet of the sampled taxa indicated that all species with defective UGT1A6 were hypercarnivores (>70% dietary animal matter). Furthermore those species with UGT1A6 defects showed evidence for reduced amino acid constraint (increased dN/dS ratios approaching the neutral selection value of 1.0) as compared with species with intact UGT1A6. In contrast, there was no evidence for reduced amino acid constraint for these same species within UGT1A1, the gene encoding the enzyme responsible for detoxification of endogenously generated bilirubin. Our results provide the first evidence suggesting that diet may have played a permissive role in the devolution of a mammalian drug metabolizing enzyme. Further work is needed to establish whether these preliminary findings can be generalized to all Carnivora. PMID:21464924

  8. Evolution of a major drug metabolizing enzyme defect in the domestic cat and other felidae: phylogenetic timing and the role of hypercarnivory.

    PubMed

    Shrestha, Binu; Reed, J Michael; Starks, Philip T; Kaufman, Gretchen E; Goldstone, Jared V; Roelke, Melody E; O'Brien, Stephen J; Koepfli, Klaus-Peter; Frank, Laurence G; Court, Michael H

    2011-01-01

    The domestic cat (Felis catus) shows remarkable sensitivity to the adverse effects of phenolic drugs, including acetaminophen and aspirin, as well as structurally-related toxicants found in the diet and environment. This idiosyncrasy results from pseudogenization of the gene encoding UDP-glucuronosyltransferase (UGT) 1A6, the major species-conserved phenol detoxification enzyme. Here, we established the phylogenetic timing of disruptive UGT1A6 mutations and explored the hypothesis that gene inactivation in cats was enabled by minimal exposure to plant-derived toxicants. Fixation of the UGT1A6 pseudogene was estimated to have occurred between 35 and 11 million years ago with all extant Felidae having dysfunctional UGT1A6. Out of 22 additional taxa sampled, representative of most Carnivora families, only brown hyena (Parahyaena brunnea) and northern elephant seal (Mirounga angustirostris) showed inactivating UGT1A6 mutations. A comprehensive literature review of the natural diet of the sampled taxa indicated that all species with defective UGT1A6 were hypercarnivores (>70% dietary animal matter). Furthermore those species with UGT1A6 defects showed evidence for reduced amino acid constraint (increased dN/dS ratios approaching the neutral selection value of 1.0) as compared with species with intact UGT1A6. In contrast, there was no evidence for reduced amino acid constraint for these same species within UGT1A1, the gene encoding the enzyme responsible for detoxification of endogenously generated bilirubin. Our results provide the first evidence suggesting that diet may have played a permissive role in the devolution of a mammalian drug metabolizing enzyme. Further work is needed to establish whether these preliminary findings can be generalized to all Carnivora. PMID:21464924

  9. Genotype and allele frequencies of drug-metabolizing enzymes and drug transporter genes affecting immunosuppressants in the Spanish white population.

    PubMed

    Bosó, Virginia; Herrero, María J; Buso, Enrique; Galán, Juan; Almenar, Luis; Sánchez-Lázaro, Ignacio; Sánchez-Plumed, Jaime; Bea, Sergio; Prieto, Martín; García, María; Pastor, Amparo; Sole, Amparo; Poveda, José Luis; Aliño, Salvador F

    2014-04-01

    Interpatient variability in drug response can be widely explained by genetically determined differences in metabolizing enzymes, drug transporters, and drug targets, leading to different pharmacokinetic and/or pharmacodynamic behaviors of drugs. Genetic variations affect or do not affect drug responses depending on their influence on protein activity and the relevance of such proteins in the pathway of the drug. Also, the frequency of such genetic variations differs among populations, so the clinical relevance of a specific variation is not the same in all of them. In this study, a panel of 33 single nucleotide polymorphisms in 14 different genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP2C19, CYP2C9, CYP3A4, CYP3A5, MTHFR, NOD2/CARD15, SLCO1A2, SLCO1B1, TPMT, and UGT1A9), encoding for the most relevant metabolizing enzymes and drug transporters relating to immunosuppressant agents, was analyzed to determine the genotype profile and allele frequencies in comparison with HapMap data. A total of 570 Spanish white recipients and donors of solid organ transplants were included. In 24 single nucleotide polymorphisms, statistically significant differences in allele frequency were observed. The largest differences (>100%) occurred in ABCB1 rs2229109, ABCG2 rs2231137, CYP3A5 rs776746, NOD2/CARD15 rs2066844, TPMT rs1800462, and UGT1A9 rs72551330. In conclusion, differences were recorded between the Spanish and other white populations in terms of allele frequency and genotypic distribution. Such differences may have implications in relation to dose requirements and drug-induced toxicity. These data are important for further research to help explain interindividual pharmacokinetic and pharmacodynamic variability in response to drug therapy. PMID:24232128

  10. Clinically relevant genetic variants of drug-metabolizing enzyme and transporter genes detected in Thai children and adolescents with autism spectrum disorder

    PubMed Central

    Medhasi, Sadeep; Pasomsub, Ekawat; Vanwong, Natchaya; Ngamsamut, Nattawat; Puangpetch, Apichaya; Chamnanphon, Montri; Hongkaew, Yaowaluck; Limsila, Penkhae; Pinthong, Darawan; Sukasem, Chonlaphat

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) among drug-metabolizing enzymes and transporters (DMETs) influence the pharmacokinetic profile of drugs and exhibit intra- and interethnic variations in drug response in terms of efficacy and safety profile. The main objective of this study was to assess the frequency of allelic variants of drug absorption, distribution, metabolism, and elimination-related genes in Thai children and adolescents with autism spectrum disorder. Blood samples were drawn from 119 patients, and DNA was extracted. Genotyping was performed using the DMET Plus microarray platform. The allele frequencies of the DMET markers were generated using the DMET Console software. Thereafter, the genetic variations of significant DMET genes were assessed. The frequencies of SNPs across the genes coding for DMETs were determined. After filtering the SNPs, 489 of the 1,931 SNPs passed quality control. Many clinically relevant SNPs, including CYP2C19*2, CYP2D6*10, CYP3A5*3, and SLCO1B1*5, were found to have frequencies similar to those in the Chinese population. These data are important for further research to investigate the interpatient variability in pharmacokinetics and pharmacodynamics of drugs in clinical practice. PMID:27110117

  11. Pharmacogenetic aspects of drug metabolizing enzymes in busulfan based conditioning prior to allogenic hematopoietic stem cell transplantation in children.

    PubMed

    Huezo-Diaz, Patricia; Uppugunduri, Chakradhara Rao S; Tyagi, Anuj Kumar; Krajinovic, Maja; Ansari, Marc

    2014-03-01

    Allogenic hematopoietic stem cell transplantation (HSCT) is a well established but complex treatment option for malignant and non-malignant disorders in pediatric patients. Most commonly used myeloablative and non-myeloablative conditioning regimens in children comprise alkylating agents, such as busulfan (BU) and cyclophosphamide. Inter-individual variability in the pharmacokinetics of BU can result in altered conditioning of the patient and therefore lead to relapse or rejection due to under exposures, or occurrence of toxicities due to over exposures. With the introduction of the intravenous formulation of BU, this variability has been reduced but still cannot be fully predicted. Inter and intra-individual variability of BU kinetics is more common in children compared to adults and toxicity of BU based regimens is still a concern. It has been hypothesized that some of this variability in BU pharmacokinetics and treatment outcomes, especially the toxicity, might be predicted by genetic variants of enzymes involved in the metabolism of BU. This review intends to summarize the studies performed to date on the pharmacokinetics and pharmacogenetics of BU based conditioning, specifically in relation to children. PMID:24524663

  12. Phosphorylation of cytochromes P450: First discovery of a posttranslational modification of a drug-metabolizing enzyme

    SciTech Connect

    Oesch-Bartlomowicz, B. . E-mail: oeschb@uni-mainz.de; Oesch, F.

    2005-12-09

    Cytochromes P450 (CYP) are important components of xenobiotic-metabolizing monooxygenases (CYP-dependent monooxygenases). Their regulation by induction, most commonly by transcriptional activation, mediated by xenobiotics, normally substrates of the corresponding CYP, is well known and has been widely studied. Our team has discovered an additional important regulation of xenobiotic-metabolizing CYPs pertaining to posttranslational modification by phosphorylation. Individual CYPs are phosphorylated by different protein kinases, leading to CYP isoenzyme-selective changes in the metabolism of individual substrates and consequent drastic changes in the control of genotoxic metabolites. Best studied are the CYP phosphorylations by the cAMP-dependent protein kinase A. Most recently, we discovered that cAMP not only leads to drastic changes in the activity of individual CYPs, but also to drastic changes in the nuclear localization of the CYP-related transcription factor Ah receptor (AHR). The consequences are very different from those of AHR nuclear translocation mediated by the classical ligands (enzyme inducers such as dioxin) and are likely to represent the long-sought physiological function of the AHR, its persistent disturbance by long-lived ligands such as dioxin may well be the reason for its high toxicity.

  13. Age-Related Changes in Hepatic Activity and Expression of Detoxification Enzymes in Male Rats

    PubMed Central

    Vyskočilová, Erika; Szotáková, Barbora; Skálová, Lenka; Bártíková, Hana; Hlaváčová, Jitka

    2013-01-01

    Process of aging is accompanied by changes in the biotransformation of xenobiotics and impairment of normal cellular functions by free radicals. Therefore, this study was designed to determine age-related differences in the activities and/or expressions of selected drug-metabolizing and antioxidant enzymes in young and old rats. Specific activities of 8 drug-metabolizing enzymes and 4 antioxidant enzymes were assessed in hepatic subcellular fractions of 6-week-old and 21-month-old male Wistar rats. Protein expressions of carbonyl reductase 1 (CBR1) and glutathione S-transferase (GST) were determined using immunoblotting. Remarkable age-related decrease in specific activities of CYP2B, CYP3A, and UDP-glucuronosyl transferase was observed, whereas no changes in activities of CYP1A2, flavine monooxygenase, aldo-keto reductase 1C, and antioxidant enzymes with advancing age were found. On the other hand, specific activity of CBR1 and GST was 2.4 folds and 5.6 folds higher in the senescent rats compared with the young ones, respectively. Interindividual variability in CBR1 activity increased significantly with rising age. We suppose that elevated activities of GST and CBR1 may protect senescent rats against xenobiotic as well as eobiotic electrophiles and reactive carbonyls, but they may alter metabolism of drugs, which are CBR1 and especially GSTs substrates. PMID:23971034

  14. Establishing population distribution of drug-metabolizing enzyme activities for the use of salivary caffeine as a dynamic liver function marker in a Singaporean Chinese population.

    PubMed

    Chia, Hazel Yiting; Yau, Wai-Ping; Ho, Han Kiat

    2016-04-01

    The salivary paraxanthine/caffeine molar ratio has been proposed as a novel dynamic liver function test to guide dose adjustments of drugs hepatically cleared by CYP1A2. Its usability requires an established population norm as well as the factors influencing the ratio and actual concentrations. To address this knowledge gap, salivary caffeine and paraxanthine concentrations were measured at 4 h post caffeine dose in healthy Chinese individuals who had undergone 24 h of caffeine abstinence. The metabolic ratio was calculated and statistical analysis was performed. From the 52 participants (26 males; 30 regular caffeine consumers) recruited, the salivary paraxanthine/caffeine molar ratio was normally distributed with a mean and SD of 0.5 ± 0.2. No statistically significant factors (BMI, body weight, gender and regularity of caffeine intake) affecting the metabolic ratio were found. The caffeine concentration and total caffeine plus paraxanthine concentrations were lower in males than in females, and lower in regular caffeine consumers than in non-regular caffeine consumers. The 4 h salivary metabolic ratio (mean: 0.5) was generally not significantly different from the literature reported salivary, serum and plasma ratios measured at 4-9 h in healthy individuals (mean range 0.4-0.7) but was significantly higher than the literature reported 6 h plasma ratio and salivary ratios measured at 1-6 h in patients with liver disease or mild abnormal liver function tests (mean range 0.03-0.2). Overall, the population norm of the salivary metabolic ratio in a Singaporean Chinese population established in this study is distinct from individuals with liver disease or mild abnormal liver function tests and provides the benchmark for dosage adjustments of drugs metabolized by CYP1A2. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26862045

  15. Genetic polymorphisms of the drug-metabolizing enzyme cytochrome P450 3A5 in a Uyghur Chinese population.

    PubMed

    Chen, Zhengshuai; Li, Jingjie; Chen, Peng; Wang, Fengjiao; Zhang, Ning; Yang, Min; Jin, Tianbo; Chen, Chao

    2016-09-01

    1.  Detection of CYP3A5 variant alleles, and knowledge about their allelic frequency in Uyghur ethnic groups, is important to establish the clinical relevance of screening for these polymorphisms to optimize pharmacotherapy. 2. We used DNA sequencing to investigate the promoter, exons and surrounding introns, and 3'-untranslated region of the CYP3A5 gene in 96 unrelated healthy Uyghur individuals. We also used SIFT and PolyPhen-2 to predict the protein function of the novel non-synonymous mutation in CYP3A5 coding regions. 3. We found 24 different CYP3A5 polymorphisms in the Uyghur population, three of which were novel: the synonymous mutation 43C > T in exon 1, two mutations 32120C > G and 32245T > C in 3'-untranslated region, and we detected the allele frequencies of CYP3A5*1 and *3 as 64.58% and 35.42%, respectively. While no subjects with CYP3A5*6 were identified. Other identified genotypes included the heterozygous genotype 1A/3A (59.38%) and 1A/3E (11.46%), which lead to decreased enzyme activity. In addition, the frequency of haplotype "TTAGGT" was the most prevalent with 0.781. 4. Our data provide new information regarding CYP3A5 genetic polymorphisms in Uyghur individuals, which may help to improve individualization of drug therapy and offer a preliminary basis for more rational use of drugs. PMID:26739429

  16. Drug-induced liver injury: the role of drug metabolism and transport.

    PubMed

    Corsini, Alberto; Bortolini, Michele

    2013-05-01

    Many studies have pinpointed the significant contribution of liver-mediated drug metabolism and transport to the complexity of drug-induced liver injury (DILI). Phase I cytochrome P450 (CYP450) enzymes can lead to altered drug metabolism and formation of toxic metabolites, whilst Phase II enzymes are also associated with DILI. The emerging role of hepatic transporters in regulating the movement of endogenous and exogenous chemicals (e.g., bile acids and drugs) across cellular and tissue membranes is critical in determining the pathophysiology of liver disease as well as drug toxicity and efficacy. Genetic and environmental factors can have a significant impact on drug metabolism and transporter proteins, consequently increasing the risk of DILI in susceptible individuals. The assessment of these factors therefore represents an important approach for predicting and preventing DILI, by better understanding the pharmacological profile of a specific drug. This review focuses on the mechanisms of DILI associated with drug metabolism and hepatic transport, and how they can be influenced by underlying factors. PMID:23436293

  17. Transporter-Enzyme Interplay: Deconvoluting Effects of Hepatic Transporters and Enzymes on Drug Disposition Using Static and Dynamic Mechanistic Models.

    PubMed

    Varma, Manthena V; El-Kattan, Ayman F

    2016-07-01

    A large body of evidence suggests hepatic uptake transporters, organic anion-transporting polypeptides (OATPs), are of high clinical relevance in determining the pharmacokinetics of substrate drugs, based on which recent regulatory guidances to industry recommend appropriate assessment of investigational drugs for the potential drug interactions. We recently proposed an extended clearance classification system (ECCS) framework in which the systemic clearance of class 1B and 3B drugs is likely determined by hepatic uptake. The ECCS framework therefore predicts the possibility of drug-drug interactions (DDIs) involving OATPs and the effects of genetic variants of SLCO1B1 early in the discovery and facilitates decision making in the candidate selection and progression. Although OATP-mediated uptake is often the rate-determining process in the hepatic clearance of substrate drugs, metabolic and/or biliary components also contribute to the overall hepatic disposition and, more importantly, to liver exposure. Clinical evidence suggests that alteration in biliary efflux transport or metabolic enzymes associated with genetic polymorphism leads to change in the pharmacodynamic response of statins, for which the pharmacological target resides in the liver. Perpetrator drugs may show inhibitory and/or induction effects on transporters and enzymes simultaneously. It is therefore important to adopt models that frame these multiple processes in a mechanistic sense for quantitative DDI predictions and to deconvolute the effects of individual processes on the plasma and hepatic exposure. In vitro data-informed mechanistic static and physiologically based pharmacokinetic models are proven useful in rationalizing and predicting transporter-mediated DDIs and the complex DDIs involving transporter-enzyme interplay. PMID:27385183

  18. Effects of methapyrilene on rat hepatic xenobiotic metabolizing enzymes and liver morphology.

    PubMed

    Graichen, M E; Neptun, D A; Dent, J G; Popp, J A; Leonard, T B

    1985-02-01

    Short-term treatment of rats with hepatocarcinogens elicits a consistent pattern of phenotypic changes in hepatic drug metabolizing enzymes, the most striking of which is a marked increase in microsomal epoxide hydrolase (EH) activity. The antihistaminic drug methapyrilene induces a high incidence of hepatocellular carcinoma in F-344 rats. The studies reported here were designed to assess the effects of methapyrilene on hepatic EH activity, cytochrome P-450-dependent mixed-function oxidase activities, liver morphology, and liver-derived serum enzymes. Male F-344 rats were treated with three daily oral doses of methapyrilene-HCl, up to 300 mg/kg/day, and were sacrificed 48 hr after the last dose. Hepatic microsomal EH and cytosolic DT-diaphorase activities were increased in a dose-related fashion, to 420 and 230% of control, respectively. Cytochrome P-450 content and benzphetamine-N-demethylase and ethoxycoumarin-O-deethylase activities were concomitantly decreased to 35-50% of control. Serum gamma-glutamyl transpeptidase and alanine aminotransferase activities were elevated 22- to 27-fold, and serum bile acids to 36-fold by treatment with methapyrilene. Periportal lesions, characterized by inflammation, nuclear and nucleolar enlargement, bile duct hyperplasia, and hepatocellular necrosis, were observed following methapyrilene administration. The severity of the periportal lesion correlated with elevations in the serum chemistry parameters. The increases noted in microsomal EH activity supports the suggestion that this enzyme may be a useful biochemical marker for exposure to hepatocarcinogens. PMID:2859228

  19. Human hepatocarcinoma functional liver cell-4 cell line exhibits high expression of drug-metabolizing enzymes in three-dimensional culture.

    PubMed

    Kato, Ryuji; Shigemoto, Kota; Akiyama, Hiromasa; Ieda, Asaka; Ijiri, Yoshio; Hayashi, Tetsuya

    2014-01-01

    The expression levels of CYP and uridine diphosphate-glucuronosyl transferase (UGT) are lower in hepatocellular carcinoma cell lines than in human primary hepatocytes. However, a functional liver cell (FLC)-4 cell line that has a greater capacity to secrete liver-specific proteins than other hepatocellular carcinoma cells has recently been established. A three-dimensional culture using Engelbreth-Holm-Swan (EHS) gel induces the secretion of liver-specific proteins via the induction of hepatocyte nuclear factor-4α (HNF-4α). The aim of this study was to evaluate the mRNA expression of the enzymes CYP and UGT in FLC-4 and HepG2 cells in monolayer and three-dimensional cultures using EHS gel. The mRNA levels of HNF-4α, albumin, pregnane X receptor (PXR), constitutive androstane receptor (CAR), CYPs (1A2, 2E1, 2C8, 2C9, 2C19, 2D6, and 3A4) and UGTs (1A1, 1A6, 1A9, and 2B7) were determined using real-time reverse transcription (RT) PCR. In a monolayer culture, the mRNA expression levels of HNF-4α, albumin, PXR, CAR, CYPs (2E1, 2C9, 2C19, 2D6, and 3A4) and UGTs (1A1, 1A6, and 1A9) were higher in FLC-4 cells than in HepG2 cells. In FLC-4 cells, the mRNA expression levels of HNF-4α, albumin, PXR, CAR, CYPs (2E1, 2C8, 2C19, and 3A4) and UGTs (1A1, 1A6, 1A9, and 2B7) significantly increased in three-dimensional culture. FLC-4 cells cultured in EHS gel showed significantly increased expression levels of CYPs and UGTs. The results of this study suggest that human hepatocellular carcinoma FLC-4 cells cultured in EHS gel show potential for use in studying in vitro drug metabolism. PMID:25366484

  20. Automated method for study of drug metabolism

    NASA Technical Reports Server (NTRS)

    Furner, R. L.; Feller, D. D.

    1973-01-01

    Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.

  1. SRC-3 is required for CAR-regulated hepatocyte proliferation and drug metabolism

    PubMed Central

    Chen, Tenghui; Chen, Qiang; Xu, Yixiang; Zhou, Qiling; Zhu, Jingwei; Zhang, Hao; Wu, Qiao; Xu, Jianming; Yu, Chundong

    2011-01-01

    Background & Aims Nuclear receptors such as pregnane X receptor and constitutive androstane receptor (CAR) are important regulators of drug-metabolizing systems such as P450s enzymes and modulate xenobiotic metabolism as well as hepatocellular proliferation. Binding of CAR to NR response elements alone is not sufficient to activate gene expression. Here we investigate the role of steroid receptor coactivator (SRC) family members in CAR-mediated hepatocyte proliferation and drug metabolism. Methods The role of SRCs in CAR activation was assessed in cell-based transfection assays and protein-protein interaction assays. The in vivo role of SRCs in CAR-mediated hepatocyte proliferation and drug metabolism was examined by using mice deficient in SRCs. Results SRC-3 displayed the highest coactivating activity to CAR compared with SRC-1 and SRC-2 in a cell-based reporter assay. Knockout of SRC-3 in mice attenuated hepatic hyperplasia induced by a CAR agonist 1,4-bis-[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP), which was associated with a reduced expression of c-Myc and Foxm-1. In contrast, knockout of SRC-1 or SRC-2 in mice did not affect TCPOBOP-induced hepatic hyperplasia. SRC-3-deficient mice were hypersensitive to zoxazolamine-induced paralysis, but were resistant to acetaminophen hepatotoxicity induced by TCPOBOP, whereas mutant mice deficient in SRC-1 or SRC-2 exhibited severe acetaminophen hepatotoxicity similar to wild-type controls. Accordingly, deficiency in SRC-3, but not SRC-1 or SRC-2, resulted in a reduced CAR-mediated expression of drug metabolism-related genes in the liver. Conclusions Our study demonstrates that SRC-3 is the predominant transcriptional coactivator among the three SRC family members for CAR activation to promote hepatocyte proliferation and drug metabolism. PMID:21827731

  2. A QUANTITATIVE MODEL FOR XENOBIOTIC METABOLIZING ENZYME (XME) INDUCTION REGULATED BY THE PREGNANE X RECEPTOR (PXR)

    EPA Science Inventory

    The nuclear receptor, PXR, is an integral part of the regulation of hepatic metabolism. It has been shown to regulate specific CYPs (phase I drug-metabolizing enzymes) as well as certain phase II drug metabolism activities, including UDP-glucuronosyl transferase (UGT), sulfotran...

  3. Effect of tetrahydrocurcumin on the profiles of drug-metabolizing enzymes induced by a high fat and high fructose diet in mice.

    PubMed

    Jearapong, Nattharat; Chatuphonprasert, Waranya; Jarukamjorn, Kanokwan

    2015-09-01

    Cytochrome P450 (CYP), a superfamily of hepatic monooxygenase enzymes, catalyzes biotransformation of endogenous compounds and xenobiotics. Modification of CYPs associated with metabolic diseases and continuous consumption of diet with excessive energy levels. Tetrahydrocurcumin (THC) exhibited beneficial effects in metabolic syndromes such as diabetic mellitus and dyslipidemia. The present study aimed to investigate the effects of THC and vitamin E (vitE) on the expression profiles of CYPs in the livers of mice fed with the high fat and high fructose diet. In addition to ad libitum access to commercial regular diet, the high fat and high fructose diet (HFD) group of adult male ICR mice was administered a HFD, which consisted of intragastric administration of hydrogenated soybean oil (1mL/day) and the addition of 20% fructose to the drinking water for 8weeks. During the induction period, subgroups of mice (n=5) were daily intragastrically administered with THC (100 or 200mg/kg/day) or vitE (100mg/kg/day). The expressions of CYP mRNA and protein were quantified using real-time PCR and the levels of these proteins were quantified using immunoblotting. Continuous consuming of high fat and high fructose for 8weeks significantly increased the expressions of Cyp1a1, Cyp1a2, Cyp1b1, Cyp2c29, and Cyp3a11 while THC ultimately normalized these CYPs profiles. In the control mice, most of the investigated CYPs was unchanged by THC, with the exception that the Cyp1a1, Cyp2b9, and Cyp3a11 proteins were elevated. These findings provided additional important information on the effects of THC on diet induced-metabolic dysfunctions. However, drug interactions due to the use of THC as an alternative supplement are of concern, particularly in the combinations that include a drug that is a substrate of Cyp1a1, Cyp2b9, and Cyp3a11. PMID:26102010

  4. Ergovaline in tall fescue and its effect on health, milk quality, biochemical parameters, oxidative status, and drug metabolizing enzymes of lactating ewes.

    PubMed

    Zbib, N; Repussard, C; Tardieu, D; Priymenko, N; Domange, C; Guerre, P

    2014-11-01

    Ergovaline (EV) produced by symbiotic association of Epichloë coenophiala with tall fescue (Lolium arundinaceum) causes toxicoses in livestock. In this study, 16 lactating ewes (BW 76.0 ± 0.6 kg) were used to determine the effects of feeding endophyte-infected (FE+) or endophyte free (FE-) tall fescue hay on animal health and performances and to investigate the putative mechanisms of action of EV. The mean EV concentrations in FE+ and FE- diets were 497 ± 52 and <5 µg/kg DM, respectively. Decreased hay consumption and BW were observed in the FE+ group. Prolactin (PRL) concentrations decreased (P < 0.02) in the FE+ group from d 3 to 28 of the study compared to the FE- group, but no consequences were observed on milk quantity or quality. Skin temperature and the thermocirculation index were lower (P < 0.05) in the FE+ than in the FE- group from d 3 to 7, but this effect disappeared from d 14 to 28. Hematocrit, mineral and biochemical, and enzymatic analyses of plasma revealed no differences between the 2 groups. Measurement of oxidative damage and antioxidant enzyme activities revealed a decrease in the activities of plasma catalase (P < 0.05), kidney glutathione reductase and peroxidase and in kidney total glutathione and malondialdehyde contents (P < 0.02) in ewes fed FE+. Hepatic flavin monooxygenase enzyme activities decreased (P < 0.01) in ewes fed FE+, except for a marked increase in the demethylation of erythromycin. This activity is linked to cytochrome P4503A content and is known to be involved in ergot alkaloid metabolism. Glutathione S-transferase activity in the kidneys decreased (P < 0.02) in the FE+ group, whereas no difference was observed in uridine diphosphate-glucuronosyltransferase activity in the liver or kidneys. The reversibility of the effect of FE+ hay on skin temperature and the increase in erythromycin N-demethylase activity may contribute to the relative resistance of ewes to EV toxicity. PMID:25253811

  5. RNA-Sequencing Quantification of Hepatic Ontogeny and Tissue Distribution of mRNAs of Phase II Enzymes in Mice

    PubMed Central

    Gunewardena, Sumedha; Cui, Julia Y.; Yoo, Byunggil; Zhong, Xiao-bo; Klaassen, Curtis D.

    2013-01-01

    Phase II conjugating enzymes play key roles in the metabolism of xenobiotics. In the present study, RNA sequencing was used to elucidate hepatic ontogeny and tissue distribution of mRNA expression of all major known Phase II enzymes, including enzymes involved in glucuronidation, sulfation, glutathione conjugation, acetylation, methylation, and amino acid conjugation, as well as enzymes for the synthesis of Phase II cosubstrates, in male C57BL/6J mice. Livers from male C57BL/6J mice were collected at 12 ages from prenatal to adulthood. Many of these Phase II enzymes were expressed at much higher levels in adult livers than in perinatal livers, such as Ugt1a6b, -2a3, -2b1, -2b5, -2b36, -3a1, and -3a2; Gsta1, -m1, -p1, -p2, and -z1; mGst1; Nat8; Comt; Nnmt; Baat; Ugdh; and Gclc. In contrast, hepatic mRNA expression of a few Phase II enzymes decreased during postnatal liver development, such as mGst2, mGst3, Gclm, and Mat2a. Hepatic expression of certain Phase II enzymes peaked during the adolescent stage, such as Ugt1a1, Sult1a1, Sult1c2, Sult1d1, Sult2as, Sult5a1, Tpmt, Glyat, Ugp2, and Mat1a. In adult mice, the total transcripts for Phase II enzymes were comparable in liver, kidney, and small intestine; however, individual Phase II enzymes displayed marked tissue specificity among the three organs. In conclusion, this study unveils for the first time developmental changes in mRNA abundance of all major known Phase II enzymes in mouse liver, as well as their tissue-specific expression in key drug-metabolizing organs. The age- and tissue-specific expression of Phase II enzymes indicate that the detoxification of xenobiotics is highly regulated by age and cell type. PMID:23382457

  6. Short-term fasting alters cytochrome P450-mediated drug metabolism in humans.

    PubMed

    Lammers, Laureen A; Achterbergh, Roos; de Vries, Emmely M; van Nierop, F Samuel; Klümpen, Heinz-Josef; Soeters, Maarten R; Boelen, Anita; Romijn, Johannes A; Mathôt, Ron A A

    2015-06-01

    Experimental studies indicate that short-term fasting alters drug metabolism. However, the effects of short-term fasting on drug metabolism in humans need further investigation. Therefore, the aim of this study was to evaluate the effects of short-term fasting (36 h) on P450-mediated drug metabolism. In a randomized crossover study design, nine healthy subjects ingested a cocktail consisting of five P450-specific probe drugs [caffeine (CYP1A2), S-warfarin (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4)] on two occasions (control study after an overnight fast and after 36 h of fasting). Blood samples were drawn for pharmacokinetic analysis using nonlinear mixed effects modeling. In addition, we studied in Wistar rats the effects of short-term fasting on hepatic mRNA expression of P450 isoforms corresponding with the five studied P450 enzymes in humans. In the healthy subjects, short-term fasting increased oral caffeine clearance by 20% (P = 0.03) and decreased oral S-warfarin clearance by 25% (P < 0.001). In rats, short-term fasting increased mRNA expression of the orthologs of human CYP1A2, CYP2C19, CYP2D6, and CYP3A4 (P < 0.05), and decreased the mRNA expression of the ortholog of CYP2C9 (P < 0.001) compared with the postabsorptive state. These results demonstrate that short-term fasting alters cytochrome P450-mediated drug metabolism in a nonuniform pattern. Therefore, short-term fasting is another factor affecting cytochrome P450-mediated drug metabolism in humans. PMID:25795462

  7. "Target-Site" Drug Metabolism and Transport.

    PubMed

    Foti, Robert S; Tyndale, Rachel F; Garcia, Kristine L P; Sweet, Douglas H; Nagar, Swati; Sharan, Satish; Rock, Dan A

    2015-08-01

    The recent symposium on "Target-Site" Drug Metabolism and Transport that was sponsored by the American Society for Pharmacology and Experimental Therapeutics at the 2014 Experimental Biology meeting in San Diego is summarized in this report. Emerging evidence has demonstrated that drug-metabolizing enzyme and transporter activity at the site of therapeutic action can affect the efficacy, safety, and metabolic properties of a given drug, with potential outcomes including altered dosing regimens, stricter exclusion criteria, or even the failure of a new chemical entity in clinical trials. Drug metabolism within the brain, for example, can contribute to metabolic activation of therapeutic drugs such as codeine as well as the elimination of potential neurotoxins in the brain. Similarly, the activity of oxidative and conjugative drug-metabolizing enzymes in the lung can have an effect on the efficacy of compounds such as resveratrol. In addition to metabolism, the active transport of compounds into or away from the site of action can also influence the outcome of a given therapeutic regimen or disease progression. For example, organic anion transporter 3 is involved in the initiation of pancreatic β-cell dysfunction and may have a role in how uremic toxins enter pancreatic β-cells and ultimately contribute to the pathogenesis of gestational diabetes. Finally, it is likely that a combination of target-specific metabolism and cellular internalization may have a significant role in determining the pharmacokinetics and efficacy of antibody-drug conjugates, a finding which has resulted in the development of a host of new analytical methods that are now used for characterizing the metabolism and disposition of antibody-drug conjugates. Taken together, the research summarized herein can provide for an increased understanding of potential barriers to drug efficacy and allow for a more rational approach for developing safe and effective therapeutics. PMID:25986849

  8. Reduction in hepatic drug metabolizing CYP3A4 activities caused by P450 oxidoreductase mutations identified in patients with disordered steroid metabolism

    SciTech Connect

    Flueck, Christa E.; Mullis, Primus E.; Pandey, Amit V.

    2010-10-08

    Research highlights: {yields} Cytochrome P450 3A4 (CYP3A4), metabolizes 50% of drugs in clinical use and requires NADPH-P450 reductase (POR). {yields} Mutations in human POR cause congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. {yields} We are reporting that mutations in POR may reduce CYP3A4 activity. {yields} POR mutants Y181D, A457H, Y459H, V492E and R616X lost 99%, while A287P, C569Y and V608F lost 60-85% CYP3A4 activity. {yields} Reduction of CYP3A4 activity may cause increased risk of drug toxicities/adverse drug reactions in patients with POR mutations. -- Abstract: Cytochrome P450 3A4 (CYP3A4), the major P450 present in human liver metabolizes approximately half the drugs in clinical use and requires electrons supplied from NADPH through NADPH-P450 reductase (POR, CPR). Mutations in human POR cause a rare form of congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. In this study we examined the effect of mutations in POR on CYP3A4 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified CYP3A4 to perform kinetic studies. We are reporting that mutations in POR identified in patients with disordered steroidogenesis/Antley-Bixler syndrome (ABS) may reduce CYP3A4 activity, potentially affecting drug metabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had more than 99% loss of CYP3A4 activity, while POR mutations A287P, C569Y and V608F lost 60-85% activity. Loss of CYP3A4 activity may result in increased risk of drug toxicities and adverse drug reactions in patients with POR mutations.

  9. Validation of in vitro cell models used in drug metabolism and transport studies; genotyping of cytochrome P450, phase II enzymes and drug transporter polymorphisms in the human hepatoma (HepG2), ovarian carcinoma (IGROV-1) and colon carcinoma (CaCo-2, LS180) cell lines

    SciTech Connect

    Brandon, Esther F.A.; Bosch, Tessa M.; Deenen, Maarten J.; Levink, Rianne; Wal, Everdina van der; Meerveld, Joyce B.M. van; Bijl, Monique; Beijnen, Jos H. |; Schellens, Jan H.M. |; Meijerman, Irma . E-mail: I.Meijerman@pharm.uu.nl

    2006-02-15

    Human cell lines are often used for in vitro biotransformation and transport studies of drugs. In vivo, genetic polymorphisms have been identified in drug-metabolizing enzymes and ABC-drug transporters leading to altered enzyme activity, or a change in the inducibility of these enzymes. These genetic polymorphisms could also influence the outcome of studies using human cell lines. Therefore, the aim of our study was to pharmacogenotype four cell lines frequently used in drug metabolism and transport studies, HepG2, IGROV-1, CaCo-2 and LS180, for genetic polymorphisms in biotransformation enzymes and drug transporters. The results indicate that, despite the presence of some genetic polymorphisms, no real effects influencing the activity of metabolizing enzymes or drug transporters in the investigated cell lines are expected. However, this characterization will be an aid in the interpretation of the results of biotransformation and transport studies using these in vitro cell models.

  10. Significant inhibitory impact of dibenzyl trisulfide and extracts of Petiveria alliacea on the activities of major drug-metabolizing enzymes in vitro: An assessment of the potential for medicinal plant-drug interactions.

    PubMed

    Murray, J; Picking, D; Lamm, A; McKenzie, J; Hartley, S; Watson, C; Williams, L; Lowe, H; Delgoda, R

    2016-06-01

    Dibenzyl trisulfide (DTS) is the major active ingredient expressed in Petiveria alliacea L., a shrub widely used for a range of conditions, such as, arthritis, asthma and cancer. Given its use alone and concomitantly with prescription medicines, we undertook to investigate its impact on the activities of important drug metabolizing enzymes, the cytochromes P450 (CYP), a key family of enzymes involved in many adverse drug reactions. DTS and seven standardized extracts from the plant were assessed for their impact on the activities of CYPs 1A2, 2C19, 2C9, 2D6 and 3A4 on a fluorometric assay. DTS revealed significant impact against the activities of CYPs 1A2, 2C19 and 3A4 with IC50 values of 1.9, 4.0 and 3.2μM, respectively, which are equivalent to known standard inhibitors of these enzymes (furafylline, and tranylcypromine), and the most potent interaction with CYP1A2 displayed irreversible enzyme kinetics. The root extract, drawn with 96% ethanol (containing 2.4% DTS), displayed IC50 values of 5.6, 3.9 and 4.2μg/mL respectively, against the same isoforms, CYPs 1A2, 2C19 and 3A4. These investigations identify DTS as a valuable CYP inhibitor and P. alliacea as a candidate plant worthy of clinical trials to confirm the conclusions that extracts yielding high DTS may lead to clinically relevant drug interactions, whilst extracts yielding low levels of DTS, such as aqueous extracts, are unlikely to cause adverse herb-drug interactions. PMID:27105957

  11. Short-term Calorie Restriction Feminizes the mRNA Profiles of Drug Metabolizing Enzymes and Transporters in Livers of Mice

    PubMed Central

    Fu, Zidong Donna; Klaassen, Curtis D.

    2015-01-01

    Calorie restriction (CR) is one of the most effective anti-aging interventions in mammals. A modern theory suggests that aging results from a decline in detoxification capabilities and thus accumulation of damaged macromolecules. The present study aimed to determine how short-term CR alters mRNA profiles of genes that encode metabolism and detoxification machinery in liver. Male C57BL/6 mice were fed CR (0, 15, 30, or 40%) diets for one month, followed by mRNA quantification of 98 xenobiotic processing genes (XPGs) in liver, including 7 uptake transporters, 39 phase-I enzymes, 37 phase-II enzymes, 10 efflux transporters, and 5 transcription factors. In general, 15% CR did not alter mRNAs of most XPGs, whereas 30 and 40% CR altered over half of the XPGs (32 increased and 29 decreased). CR up-regulated some phase-I enzymes (fold increase), such as Cyp4a14 (12), Por (2.3), Nqo1 (1.4), Fmo2 (5.4), and Fmo3 (346), and numerous number of phase-II enzymes, such as Sult1a1 (1.2), Sult1d1 (2.0), Sult1e1 (33), Sult3a1 (2.2), Gsta4 (1.3), Gstm2 (1.3), Gstm3 (1.7), and Mgst3 (2.2). CR feminized the mRNA profiles of 32 XPGs in livers of male mice. For instance, CR decreased the male-predominantly expressed Oatp1a1 (97%) and increased the female-predominantly expressed Oatp1a4 (11). In conclusion, short-term CR alters the mRNA levels of over half of the 98 XPGs quantified in livers of male mice, and over half of these alterations appear to be due to feminization of the liver. PMID:24240088

  12. Short-term calorie restriction feminizes the mRNA profiles of drug metabolizing enzymes and transporters in livers of mice.

    PubMed

    Fu, Zidong Donna; Klaassen, Curtis D

    2014-01-01

    Calorie restriction (CR) is one of the most effective anti-aging interventions in mammals. A modern theory suggests that aging results from a decline in detoxification capabilities and thus accumulation of damaged macromolecules. The present study aimed to determine how short-term CR alters mRNA profiles of genes that encode metabolism and detoxification machinery in the liver. Male C57BL/6 mice were fed CR (0, 15, 30, or 40%) diets for one month, followed by mRNA quantification of 98 xenobiotic processing genes (XPGs) in the liver, including 7 uptake transporters, 39 phase-I enzymes, 37 phase-II enzymes, 10 efflux transporters, and 5 transcription factors. In general, 15% CR did not alter mRNAs of most XPGs, whereas 30 and 40% CR altered over half of the XPGs (32 increased and 29 decreased). CR up-regulated some phase-I enzymes (fold increase), such as Cyp4a14 (12), Por (2.3), Nqo1 (1.4), Fmo2 (5.4), and Fmo3 (346), and numerous number of phase-II enzymes, such as Sult1a1 (1.2), Sult1d1 (2.0), Sult1e1 (33), Sult3a1 (2.2), Gsta4 (1.3), Gstm2 (1.3), Gstm3 (1.7), and Mgst3 (2.2). CR feminized the mRNA profiles of 32 XPGs in livers of male mice. For instance, CR decreased the male-predominantly expressed Oatp1a1 (97%) and increased the female-predominantly expressed Oatp1a4 (11). In conclusion, short-term CR alters the mRNA levels of over half of the 98 XPGs quantified in livers of male mice, and over half of these alterations appear to be due to feminization of the liver. PMID:24240088

  13. Drug metabolism and transport during pregnancy: how does drug disposition change during pregnancy and what are the mechanisms that cause such changes?

    PubMed

    Isoherranen, Nina; Thummel, Kenneth E

    2013-02-01

    There is increasing evidence that pregnancy alters the function of drug-metabolizing enzymes and drug transporters in a gestational-stage and tissue-specific manner. In vivo probe studies have shown that the activity of several hepatic cytochrome P450 enzymes, such as CYP2D6 and CYP3A4, is increased during pregnancy, whereas the activity of others, such as CYP1A2, is decreased. The activity of some renal transporters, including organic cation transporter and P-glycoprotein, also appears to be increased during pregnancy. Although much has been learned, significant gaps still exist in our understanding of the spectrum of drug metabolism and transport genes affected, gestational age-dependent changes in the activity of encoded drug metabolizing and transporting processes, and the mechanisms of pregnancy-induced alterations. In this issue of Drug Metabolism and Disposition, a series of articles is presented that address the predictability, mechanisms, and magnitude of changes in drug metabolism and transport processes during pregnancy. The articles highlight state-of-the-art approaches to studying mechanisms of changes in drug disposition during pregnancy, and illustrate the use and integration of data from in vitro models, animal studies, and human clinical studies. The findings presented show the complex inter-relationships between multiple regulators of drug metabolism and transport genes, such as estrogens, progesterone, and growth hormone, and their effects on enzyme and transporter expression in different tissues. The studies provide the impetus for a mechanism- and evidence-based approach to optimally managing drug therapies during pregnancy and improving treatment outcomes. PMID:23328895

  14. Short-term calorie restriction feminizes the mRNA profiles of drug metabolizing enzymes and transporters in livers of mice

    SciTech Connect

    Fu, Zidong Donna; Klaassen, Curtis D.

    2014-01-01

    Calorie restriction (CR) is one of the most effective anti-aging interventions in mammals. A modern theory suggests that aging results from a decline in detoxification capabilities and thus accumulation of damaged macromolecules. The present study aimed to determine how short-term CR alters mRNA profiles of genes that encode metabolism and detoxification machinery in the liver. Male C57BL/6 mice were fed CR (0, 15, 30, or 40%) diets for one month, followed by mRNA quantification of 98 xenobiotic processing genes (XPGs) in the liver, including 7 uptake transporters, 39 phase-I enzymes, 37 phase-II enzymes, 10 efflux transporters, and 5 transcription factors. In general, 15% CR did not alter mRNAs of most XPGs, whereas 30 and 40% CR altered over half of the XPGs (32 increased and 29 decreased). CR up-regulated some phase-I enzymes (fold increase), such as Cyp4a14 (12), Por (2.3), Nqo1 (1.4), Fmo2 (5.4), and Fmo3 (346), and numerous number of phase-II enzymes, such as Sult1a1 (1.2), Sult1d1 (2.0), Sult1e1 (33), Sult3a1 (2.2), Gsta4 (1.3), Gstm2 (1.3), Gstm3 (1.7), and Mgst3 (2.2). CR feminized the mRNA profiles of 32 XPGs in livers of male mice. For instance, CR decreased the male-predominantly expressed Oatp1a1 (97%) and increased the female-predominantly expressed Oatp1a4 (11). In conclusion, short-term CR alters the mRNA levels of over half of the 98 XPGs quantified in livers of male mice, and over half of these alterations appear to be due to feminization of the liver. - Highlights: • Utilized a graded CR model in male mice • The mRNA profiles of xenobiotic processing genes (XPGs) in liver were investigated. • CR up-regulates many phase-II enzymes. • CR tends to feminize the mRNA profiles of XPGs.

  15. POLYCHLORINATED BIPHENYLS AS INDUCERS OF HEPATIC MICROSOMAL ENZYMES: STRUCTURE-ACTIVITY RULES

    EPA Science Inventory

    A number of highly purified polychlorinated biphenyl (PCB) isomers and congeners were synthesized and administered to male Wistar rats at dosage levels of 30 and 150 micromol/kg. The effects of this in vivo treatment on the drug-metabolizing enzymes were determined by measuring t...

  16. N-vinylpyrrolidone dimer, a novel formulation excipient, causes hepatic and thyroid hypertrophy through the induction of hepatic microsomal enzymes in rats.

    PubMed

    Yang, Yi; Ciurlionis, Rita; Kowalkowski, Kenneth; Marsh, Kennan C; Bracken, William M; Blomme, Eric A G

    2012-01-01

    N-vinylpyrrolidone dimer (VPD) is a novel experimental formulation excipient intended for preclinical toxicology studies. In a previous 4-week toxicity study, VPD induced dose-dependent hepatocellular and thyroid gland hypertrophy in Sprague-Dawley (SD) rats. The objectives of the current investigation were to define the underlying molecular mechanisms of these changes. Two separate studies were conducted using male SD rats, daily doses of 300, 1000 or 3,000 mg/kg of VPD, and a positive control (phenobarbital at 75 mg/kg/day): (1) a 28-day study to monitor thyroid hormone levels after 7 and 28 days of dosing; (2) a 5-day study to evaluate hepatic and thyroid gland transcriptomic changes, as well as hepatic UGT activity levels. At VPD dosages of 300 mg/kg/day and higher, 2-fold increases of serum thyroid stimulating hormone (TSH) levels were observed in male SD rats after 28 days of dosing, while serum thyroxine (T4) and triiodothyronine (T3) levels were unchanged. Liver UGT enzyme activity levels were increased in VPD-treated rats after 5 days. In addition, in the 5-day study, VPD caused increased hepatic mRNA levels of a panel of drug metabolizing enzymes (DMEs) and transporters, including Cyp3a1, Cyp2b1, Ugt 2b1, and Abcc3. Similar patterns of induction were observed in primary rat hepatocytes exposed to VPD. Transcriptomic changes in the thyroid gland were identified for genes involved in thyroid hormone biosynthesis and in the FAK, PTEN, and Wnt/β-catenin signaling pathways. Collectively, these data indicate that VPD acts as an inducer of hepatic DMEs in SD rats and that this likely leads to enhanced peripheral metabolism of T3/T4, resulting in a feedback response characterized by increased serum TSH levels, and thyroid gland hypertrophy and hyperplasia. PMID:22037397

  17. Screening of Drug Metabolizing Enzymes for the Ginsenoside Compound K In Vitro: An Efficient Anti-Cancer Substance Originating from Panax Ginseng

    PubMed Central

    Lin, Xiu-Xian; Peng, Shi-Fang; Xiao, Mei-Fang; Huang, Wei-Hua; Wang, Yi-Cheng; Peng, Jing-Bo; Zhang, Wei; Ouyang, Dong-Sheng; Chen, Yao

    2016-01-01

    Ginsenoside compound K (CK), a rare ginsenoside originating from Panax Ginseng, has been found to possess unique pharmacological activities specifically as anti-cancers. However, the role of cytochrome P450s (CYPs) in the metabolism of CK is unclear. In this study, we screened the CYPs for the metabolism of CK in vitro using human liver microsomes (HLMs) or human recombinant CYPs. The results showed that CK inhibited the enzyme activities of CYP2C9 and CYP3A4 in the HLMs. The Km and Vmax values of CK were 84.20±21.92 μM and 0.28±0.04 nmol/mg protein/min, respectively, for the HLMs; 34.63±10.48 μM and 0.45±0.05 nmol/nmol P450/min, respectively, for CYP2C9; and 27.03±5.04 μM and 0.68±0.04 nmol/nmol P450/min, respectively, for CYP3A4. The IC50 values were 16.00 μM and 9.83 μM, and Ki values were 14.92 μM and 11.42μM for CYP2C9 and CYP3A4, respectively. Other human CYP isoforms, including CYP1A2, CYP2A6, CYP2D6, CYP2E1, and CYP2C19, showed minimal or no effect on CK metabolism. The results suggested that CK was a substrate and also inhibitors for both CYP2C9 and CYP3A4. Patients using CK in combination with therapeutic drugs that are substrates of CYP2C9 and CYP3A4 for different reasons should be careful, although the inhibiting potency of CK is much poorer than that of enzyme-specific inhibitors. PMID:26845774

  18. Effects of Aging on mRNA Profiles for Drug-Metabolizing Enzymes and Transporters in Livers of Male and Female Mice

    PubMed Central

    Fu, Zidong Donna; Csanaky, Iván L.

    2012-01-01

    Aging is a physiological process characterized by progressive functional decline in various organs over time. To reveal possible molecular mechanisms of altered xenobiotic disposition and toxicity in elderly individuals, age-dependent mRNA profiles for 101 xenobiotic-processing genes (XPGs), including seven uptake transporters, 41 phase I enzymes, 36 phase II enzymes, 10 efflux transporters, and seven transcription factors, were characterized in livers of male and female mice from 3 to 27 months of age. Gender differences across the lifespan (significant at five ages or more) were observed for 52 XPGs, including 15 male-predominant genes (e.g., Oatp1a1, Cyp3a11, Ugt1a6a, Comt, and Bcrp) and 37 female-predominant genes (e.g., Oatp1a4, Cyp2b10, Sult1a1, Ugt1a1, and Mrp3). During aging, the mRNA levels for 44% of the 101 XPGs changed in male mice and 63% changed in female mice. In male mice, mRNA levels for 40 XPGs (e.g., Oatp1a1, Ces2c, Gstm4, Gstp1, and Ces1e) were lower in aged mice (more than 21 months of age), whereas mRNA levels for four XPGs (e.g., Oat2 and Gstm2) were higher in aged mice. In female mice, mRNA levels for 43 XPGs (e.g., Oatp1a1, Cyp1a2, Ces1f, Sult3a1, Gstt2, Comt, Ent1, Fmo3, and Mrp6) were lower in aged mice, whereas mRNA levels for 21 XPGs (e.g., Oatp1a4, Nqo1, Adh7, Sult2a1/2, Gsta1, and Mrp4) were higher in aged mice. In conclusion, 51% of the 101 XPGs exhibited gender differences in liver mRNA levels across the lifespan of mice; the mRNA levels for 40% of the XPGs were lower in aged male mice and 43% were lower in aged female mice. PMID:22446518

  19. Genetic polymorphism analysis of the drug-metabolizing enzyme CYP1A2 in a Uyghur Chinese population: a pilot study.

    PubMed

    Geng, Tingting; Zhang, Xi Yang; Wang, Li; Wang, Huijuan; Shi, Xugang; Kang, Longli; Hou, Peng; Jin, Tianbo

    2016-06-01

    1. CYP1A2 is a highly polymorphic gene and CYP1A2 enzyme results in broad inter-individual variability in response to certain pharmacotherapies, while little is known about the genetic variation of CYP1A2 in Uyghur Chinese population. The aim of the present study was to screen Uyghur volunteers for CYP1A2 genetic polymorphisms. 2. We used DNA sequencing to investigate promoter, exons, introns, and 3' UTR of the CYP1A2 gene in 96 unrelated healthy Uyghur individuals. We also used SIFT (Sorting Intolerant From Tolerant) and PolyPhen-2 (Polymorphism Phenotyping v2) to predict the protein function of the novel non-synonymous mutation in CYP1A2 coding regions. 3. We identified 20 different CYP1A2 polymorphisms in the Uyghur Chinese population, including two novel variants (119A > G and 2410G > A). Variant 119A > G was predicted to be probably damaging on protein function by PolyPhen-2, by contrast, 2410G > A was identified as benign. The allele frequencies of CYP1A2*1A, *1B, *1F, *1G, *1J, *1M, *4, and *9 were 23.4%, 53.1%, 3.7%, 2.6%, 2.6%, 13.5%, 0.5%, and 0.5%, respectively. The frequency of *1F, a putative high inducibility allele, was higher in our sample population compared with that in the Caucasian population (p < 0.05). The most common genotype combinations were *1A/*1B (46.9%) and *1B/*1M (27.1%). 4. Our results provide basic information on CYP1A2 polymorphisms in Uyghur individuals and suggest that the enzymatic activities of CYP1A2 may differ among the diverse ethnic populations of the world. PMID:26383175

  20. Low-Turnover Drug Molecules: A Current Challenge for Drug Metabolism Scientists.

    PubMed

    Hutzler, J Matthew; Ring, Barbara J; Anderson, Shelby R

    2015-12-01

    In vitro assays using liver subcellular fractions or suspended hepatocytes for characterizing the metabolism of drug candidates play an integral role in the optimization strategy employed by medicinal chemists. However, conventional in vitro assays have limitations in their ability to predict clearance and generate metabolites for low-turnover (slowly metabolized) drug molecules. Due to a rapid loss in the activity of the drug-metabolizing enzymes, in vitro incubations are typically performed for a maximum of 1 hour with liver microsomes to 4 hours with suspended hepatocytes. Such incubations are insufficient to generate a robust metabolic response for compounds that are slowly metabolized. Thus, the challenge of accurately estimating low human clearance with confidence has emerged to be among the top challenges that drug metabolism scientists are confronted with today. In response, investigators have evaluated novel methodologies to extend incubation times and more sufficiently measure metabolism of low-turnover drugs. These methods include plated human hepatocytes in monoculture, and a novel in vitro methodology using a relay of sequential incubations with suspended cryopreserved hepatocytes. In addition, more complex in vitro cellular models, such as HepatoPac (Hepregen, Medford, MA), a micropatterned hepatocyte-fibroblast coculture system, and the HµREL (Beverley Hills, CA) hepatic coculture system, have been developed and characterized that demonstrate prolonged enzyme activity. In this review, the advantages and disadvantages of each of these in vitro methodologies as it relates to the prediction of clearance and metabolite identification will be described in an effort to provide drug metabolism scientists with the most up-to-date experimental options for dealing with the complex issue of low-turnover drug candidates. PMID:26363026

  1. Induction of microsomal drug metabolism in man and in the rat by exposure to petroleum.

    PubMed Central

    Harman, A W; Frewin, D B; Priestly, B G

    1981-01-01

    To determine the effect of petroleum exposure on the activity of hepatic mixed function oxidase enzymes, salivary elimination kinetics of antipyrine were determined in 19 petrol station attendants and compared with 19 controls. Antipyrine half life in petrol station attendants was shorter than in controls. Microsomal preparations (10 000 x g supernatants) were prepared from six male Porton rats exposed to petrol vapour (5 ppm at an air flow rate of 41/min for eight hours a day for three weeks) and six control rats maintained under the same conditions without exposure to petrol vapour. The rates of oxidative metabolism of antipyrine, aminopyrine, ethylmorphine, aniline, and benzo(a)pyrene were all increased by more than 45% in the petrol-exposed rats. The results indicate that petrol vapour is a moderately potent inducer of mixed function oxidase activity in rats, and that occupational exposure to petroleum may result in enhanced microsomal drug metabolism. PMID:7470408

  2. Interaction of cadmium with hepatic and testicular microsomal enzymes

    SciTech Connect

    Wetzel, L.T.

    1982-01-01

    Cadmium, a ubiquitous environmental pollutant, inhibits or activates a number of microsomal enzymes. Among the enzymes affected by cadmium are cytochrome P-450 containing mixed-function oxidases (MFO) which are present in both the liver and testis. Cadmium affects MFO activity, and as a result, cadmium-induced alterations in BP metabolism might alter BP toxicity in the liver or testis. In addition, MFO essential for testosterone production are located in the testis and cadmium-MFO interactions in the testis might alter androgen production. Therefore studies were carried out to evaluate the interaction of cadmium with heptic and testicular MFO. The results indicated that cadmium affected the activities of hepatic and testicular MFO and in so doing may influence the toxicity of BP and other chemicals in liver and testes. In addition, exposure to metals may also compromise testicular androgen biosynthesis.

  3. Drug metabolism by cultured human hepatocytes: how far are we from the in vivo reality?

    PubMed

    Ponsoda, Xavier; Donato, M Teresa; Perez-Cataldo, Gabriela; Gómez-Lechón, Maria José; Castell, José V

    2004-06-01

    The investigation of metabolism is an important milestone in the course of drug development. Drug metabolism is a determinant of drug pharmacokinetics variability in human beings. Fundamental to this are phenotypic differences, as well as genotypic differences, in the expression of the enzymes involved in drug metabolism. Genotypic variability is easy to identify by means of polymerase chain reaction-based or DNA chip-based methods, whereas phenotypic variability requires direct measurement of enzyme activities in liver, or, indirectly, measurement of the rate of metabolism of a given compound in vivo. There is a great deal of phenotypic variability in human beings, only a minor part being attributable to gene polymorphisms. Thus, enzyme activity measurements in a series of human livers, as well as in vivo studies with human volunteers, show that phenotypic variability is, by far, much greater than genotypic variability. In vitro models are currently used to investigate the hepatic metabolism of new compounds. Cultured human hepatocytes are considered to be the closest model to the human liver. However, the fact that hepatocytes are placed in a microenvironment that differs from that of the cells in the liver raises the question of to what extent drug metabolism variability observed in vitro actually reflects that in the liver in vivo. This issue has been examined by investigating the metabolism of the model compound, aceclofenac (an approved analgesic/anti-inflammatory drug), both in vitro and in vivo. Hepatocytes isolated from programmed liver biopsies were incubated with aceclofenac, and the metabolites formed were investigated by HPLC. The patients were given the drug during the course of clinical recovery, and the metabolites, largely present in urine, were analysed. In vitro and in vivo data from the same individual were compared. There was a good correlation between the in vitro and in vivo relative abundance of oxidised metabolites (4'-OH-aceclofenac + 4

  4. Interindividual Variability in Cytochrome P450-Mediated Drug Metabolism.

    PubMed

    Tracy, Timothy S; Chaudhry, Amarjit S; Prasad, Bhagwat; Thummel, Kenneth E; Schuetz, Erin G; Zhong, Xiao-Bo; Tien, Yun-Chen; Jeong, Hyunyoung; Pan, Xian; Shireman, Laura M; Tay-Sontheimer, Jessica; Lin, Yvonne S

    2016-03-01

    The cytochrome P450 (P450) enzymes are the predominant enzyme system involved in human drug metabolism. Alterations in the expression and/or activity of these enzymes result in changes in pharmacokinetics (and consequently the pharmacodynamics) of drugs that are metabolized by this set of enzymes. Apart from changes in activity as a result of drug-drug interactions (by P450 induction or inhibition), the P450 enzymes can exhibit substantial interindividual variation in basal expression and/or activity, leading to differences in the rates of drug elimination and response. This interindividual variation can result from a myriad of factors, including genetic variation in the promoter or coding regions, variation in transcriptional regulators, alterations in microRNA that affect P450 expression, and ontogenic changes due to exposure to xenobiotics during the developmental and early postnatal periods. Other than administering a probe drug or cocktail of drugs to obtain the phenotype or conducting a genetic analysis to determine genotype, methods to determine interindividual variation are limited. Phenotyping via a probe drug requires exposure to a xenobiotic, and genotyping is not always well correlated with phenotype, making both methodologies less than ideal. This article describes recent work evaluating the effect of some of these factors on interindividual variation in human P450-mediated metabolism and the potential utility of endogenous probe compounds to assess rates of drug metabolism among individuals. PMID:26681736

  5. Evaluation of human hepatocytes cultured by three-dimensional spheroid systems for drug metabolism.

    PubMed

    Ohkura, Takako; Ohta, Kunihiro; Nagao, Takuya; Kusumoto, Kumiko; Koeda, Akiko; Ueda, Tadayoshi; Jomura, Tomoko; Ikeya, Takeshi; Ozeki, Emiko; Wada, Kazuki; Naitoh, Kazushi; Inoue, Yukiko; Takahashi, Naoki; Iwai, Hisakazu; Arakawa, Hiroshi; Ogihara, Takuo

    2014-01-01

    We investigated the utility of three-dimensional (3D) spheroid cultures of human hepatocytes in discovering drug metabolites. Metabolites of acetaminophen, diclofenac, lamotrigine, midazolam, propranolol and salbutamol were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) to measure enzyme activities in this system cultured for 2 and 7 days. Sequential metabolic reactions by Phase I and then Phase II enzymes were found in diclofenac [CYP2C9 and UDP-glucuronyltransferases (UGTs)], midazolam (CYP3A4 and UGTs) and propranolol (CYP1A2/2D6 and UGTs). Moreover, lamotrigine and salbutamol were metabolized to lamotrigine-N-glucuronide and salbutamol 4-O-sulfate, respectively. These metabolites, which are human specific, could be observed in clinical studies, but not in conventional hepatic culture systems as in previous reports. Acetaminophen was metabolized to glucuronide and sulfate conjugates, and N-acetyl-p-benzo-quinoneimine (NAPQI) and its metabolites were not observed. In addition, mRNA of drug-metabolism enzymes [CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, UGT1A1, UGT2B7, sulfotransferase 1A1 (SULT1A1) and glutathione S-transferase pi 1 (GSTP1)], which were measured by qRT-PCR, were expressed in the human hepatocyte spheroids. In conclusion, these results suggest that human hepatocyte spheroids are useful in discovering drug metabolites. PMID:24695277

  6. Drug Metabolism within the Brain Changes Drug Response: Selective Manipulation of Brain CYP2B Alters Propofol Effects

    PubMed Central

    Khokhar, Jibran Y; Tyndale, Rachel F

    2011-01-01

    Drug-metabolizing cytochrome P450 (CYPs) enzymes are expressed in the liver, as well as in extrahepatic tissues such as the brain. Here we show for the first time that drug metabolism by a CYP within the brain, illustrated using CYP2B and the anesthetic propofol (2, 6-diisopropylphenol, Diprivan), can meaningfully alter the pharmacological response to a CNS acting drug. CYP2B is expressed in the brains of animals and humans, and this CYP isoform is able to metabolize centrally acting substrates such as propofol, ecstasy, and serotonin. Rats were given intracerebroventricularly (i.c.v.) injections of vehicle, C8-xanthate, or 8-methoxypsoralen (CYP2B mechanism-based inhibitors) and then tested for sleep time following propofol (80 mg/kg intraperitoneally). Both inhibitors significantly increased sleep-time (1.8- to 2-fold) and brain propofol levels, while having no effect on plasma propofol levels. Seven days of nicotine treatment can induce the expression of brain, but not hepatic, CYP2B, and this induction reduced propofol sleep times by 2.5-fold. This reduction was reversed in a dose-dependent manner by i.c.v. injections of inhibitor. Sleep times correlated with brain (r=0.76, P=0.0009), but not plasma (r=0.24, P=0.39) propofol concentrations. Inhibitor treatments increased brain, but not plasma, propofol levels, and had no effect on hepatic enzyme activity. These data indicate that brain CYP2B can metabolize neuroactive substrates (eg, propofol) and can alter their pharmacological response. This has wider implications for localized CYP-mediated metabolism of drugs, neurotransmitters, and neurotoxins within the brain by this highly variable enzyme family and other CYP subfamilies expressed in the brain. PMID:21107310

  7. Discussion-Based Instruction in Drug Metabolism.

    ERIC Educational Resources Information Center

    Ruenitz, Peter C.

    1995-01-01

    A flexible strategy for large-group pharmacy instruction in drug metabolism has students prepare and discuss answers to fact-oriented study questions, addressing fundamentals covered in a textbook, with regular evaluation of in-class student responses to higher-order review questions. This discussion-based approach has brought sustained…

  8. Hepatic drug-oxidizing enzyme systems and urinary D-glucaric acid excretion in patients with congestive heart failure.

    PubMed Central

    Tokola, O; Pelkonen, O; Karki, N T; Luoma, P

    1975-01-01

    Drug-oxidizing enzyme systems in liver biopsy samples and the urinary excretion of D-glucaric acid were studied in two different groups of patients with cardiac insufficiency. 2. In one group of six patients, the activities of drug-metabolizing enzymes had decreased considerably as compared with the control values, but in four liver samples from patients treated with oral hypoglycaemic agents for their diabetes, activities were higher than in control samples from ten patients. 3. In the other group of seven patients, the urinary excretion of D-glucaric acid (isolated by ion-exchange chromatography) was 60% lower than in the control group of nine humans, whereas in four patients taking antiepileptic agents excretion rate was higher than control values. 4. Because the age distribution was markedly different between cardiac insufficiency and control groups, it is difficult to conclude, if the impairment of drug metabolism was a consequence of the old age or of the disease process. However, drug-oxidizing enzyme systems seem to be inducible also in old age. 5. The results support further the opinion that the urinary excretion of D-glucaric acid may be one useful index in assessing an individual's capacity to metabolize foreign compounds especially in the patients with lowered drug metabolizing capacity. PMID:786355

  9. A Pharmacogenetic Screening Experiment Demonstrating Principles of Genetic Constitution on Drug Metabolism.

    ERIC Educational Resources Information Center

    Robbins, Doris K.; Wedlund, Peter J.

    1990-01-01

    A laboratory experiment designed to provide rapid, inexpensive student exposure to pharmacogenetics in drug elimination and patient therapy is described. The test, performed on students, determines expression of a drug metabolism enzyme following ingestion of a probe drug. (Author/MSE)

  10. Clinical review: Drug metabolism and nonrenal clearance in acute kidney injury

    PubMed Central

    Vilay, A Mary; Churchwell, Mariann D; Mueller, Bruce A

    2008-01-01

    Decreased renal drug clearance is an obvious consequence of acute kidney injury (AKI). However, there is growing evidence to suggest that nonrenal drug clearance is also affected. Data derived from human and animal studies suggest that hepatic drug metabolism and transporter function are components of nonrenal clearance affected by AKI. Acute kidney injury may also impair the clearance of formed metabolites. The fact that AKI does not solely influence kidney function may have important implications for drug dosing, not only of renally eliminated drugs but also of those that are hepatically cleared. A review of the literature addressing the topic of drug metabolism and clearance alterations in AKI reveals that changes in nonrenal clearance are highly complicated and poorly studied, but they may be quite common. At present, our understanding of how AKI affects drug metabolism and nonrenal clearance is limited. However, based on the available evidence, clinicians should be cognizant that even hepatically eliminated drugs and formed drug metabolites may accumulate during AKI, and renal replacement therapy may affect nonrenal clearance as well as drug metabolite clearance. PMID:19040780

  11. Nuclear Receptors in Drug Metabolism, Drug Response and Drug Interactions

    PubMed Central

    Prakash, Chandra; Zuniga, Baltazar; Song, Chung Seog; Jiang, Shoulei; Cropper, Jodie; Park, Sulgi; Chatterjee, Bandana

    2016-01-01

    Orally delivered small-molecule therapeutics are metabolized in the liver and intestine by phase I and phase II drug-metabolizing enzymes (DMEs), and transport proteins coordinate drug influx (phase 0) and drug/drug-metabolite efflux (phase III). Genes involved in drug metabolism and disposition are induced by xenobiotic-activated nuclear receptors (NRs), i.e. PXR (pregnane X receptor) and CAR (constitutive androstane receptor), and by the 1α, 25-dihydroxy vitamin D3-activated vitamin D receptor (VDR), due to transactivation of xenobiotic-response elements (XREs) present in phase 0-III genes. Additional NRs, like HNF4-α, FXR, LXR-α play important roles in drug metabolism in certain settings, such as in relation to cholesterol and bile acid metabolism. The phase I enzymes CYP3A4/A5, CYP2D6, CYP2B6, CYP2C9, CYP2C19, CYP1A2, CYP2C8, CYP2A6, CYP2J2, and CYP2E1 metabolize >90% of all prescription drugs, and phase II conjugation of hydrophilic functional groups (with/without phase I modification) facilitates drug clearance. The conjugation step is mediated by broad-specificity transferases like UGTs, SULTs, GSTs. This review delves into our current understanding of PXR/CAR/VDR-mediated regulation of DME and transporter expression, as well as effects of single nucleotide polymorphism (SNP) and epigenome (specified by promoter methylation, histone modification, microRNAs, long non coding RNAs) on the expression of PXR/CAR/VDR and phase 0-III mediators, and their impacts on variable drug response. Therapeutic agents that target epigenetic regulation and the molecular basis and consequences (overdosing, underdosing, or beneficial outcome) of drug-drug/drug-food/drug-herb interactions are also discussed. Precision medicine requires understanding of a drug’s impact on DME and transporter activity and their NR-regulated expression in order to achieve optimal drug efficacy without adverse drug reactions. In future drug screening, new tools such as humanized mouse models and

  12. The ameliorating effects of vitamin E on hepatic antioxidant system and xenobiotic-metabolizing enzymes in fenvalerate-exposed iodine-deficient rats.

    PubMed

    Kocer-Gumusel, Belma; Erkekoglu, Pinar; Caglayan, Aydan; Hincal, Filiz

    2016-07-01

    This study investigated the effects of vitamin E (VE) on hepatic antioxidant system and drug-metabolizing enzymes in fenvalerate (FEN)-exposed iodine-deficient (ID) Wistar rats. ID was produced by perchlorate containing drinking water. VE was introduced by a loading dose of 100 mg/kg/d, i.g. for the first three days in the last week of feeding period; then with a single maintenance dose of 40 mg/kg on the 4th day. During last week, FEN groups (F) received 100 mg/kg/d, i.p. FEN. VE alone did not significantly affect thyroid hormones and antioxidant parameters; however, significantly increased total cytochrome P450 (38%) and cytochrome b5 levels (36%). In all ID groups, plasma thyroid-stimulating hormone (TSH) levels increased markedly, but remained at control level in vitamin E plus FEN receiving iodine-deficient group (IDVF) group. Glutathione peroxidase activity showed marked increases in F (19%) and FEN-exposed iodine-deficient group (IDF, 48%) groups. FEN treatment significantly increased total cytochrome P450 (28%) and thiobarbituric acid reactive substance levels (36%), as well as 7-ethoxyresorufin O-deethylase (120%), 7-penthoxyresorufin O-deethylase (139%) and glutathione S-transferase (15%) activities and decreased total glutathione concentrations (28%) versus control. Overall results suggest that vitamin E has ameliorating effects on the measured parameters in ID and/or FEN exposure. PMID:26446907

  13. Influence of diet and nutritional status on drug metabolism.

    PubMed

    Walter-Sack, I; Klotz, U

    1996-07-01

    Genetic and environmental factors contribute to a wide inter- and intraindividual variability in drug metabolism. Among the environmental factors that may influence drug metabolism, the diet and nutritional status of the individuals are important determinants. As altered drug-metabolising enzyme activities can influence the intensity and duration of drug action, such factors should be considered in pharmacotherapy. For this reason the effects of dietary energy, protein deficiency, nutritional ingredients, special diet forms and nutrition regimens and malnutritional states must be differentiated. In various pharmacokinetic studies different model drugs metabolised either by oxidative phase I pathways [e.g. phenazone (antipyrine), aminopyrine, phenacetin, theophylline, propranolol, nifedipine] or phase II conjugation reactions [e.g. paracetamol (acetaminophen), oxazepam] were used and from the calculated pharmacokinetic data some information on the involved and affected drug-metabolising enzymes [e.g. cytochrome P450 (CYP) subspecies, glucuronosyltransferases] can be generated. It is well known that smoking, charcoal broiled food or cruciferous vegetables induce the metabolism of many xenobiotics, whereas grapefruit juice increases the oral bioavailability of the high clearance drugs nifedipine, nitrendipine or felodipine by inhibiting their presystemic (intestinal) elimination. Energy deficiency, and especially a low intake of protein, will cause a decrease of about 20 to 40% in phenazone and theophylline clearance and elimination of those drugs can be accelerated by a protein-rich diet. In the same way, protein deficiency induced by either vegetarian food or undernourishment will have the opposite pharmacokinetic consequences. On the basis of some more examples from the literature it is emphasised that the variable influence of the above factors should be taken into account in study participant selection and study design when the pharmacokinetics of a drug must be

  14. POLYCHLORINATED BIPHENYLS AS INDUCERS OF HEPATIC MICROSOMAL ENZYMES: EFFECTS OF DI-ORTHO SUBSTITUTION

    EPA Science Inventory

    All of the 13 possible polychlorinated biphenyl (PCB) isomers and congeners substituted at both para positions, at least two meta positions (but not necessarily on the same ring) and at two ortho positions have been synthesized and tested as rat hepatic microsomal enzyme inducers...

  15. Vanadium chemoprevention of 7,12-dimethylbenz(a)anthracene-induced rat mammary carcinogenesis: probable involvement of representative hepatic phase I and II xenobiotic metabolizing enzymes.

    PubMed

    Bishayee, A; Oinam, S; Basu, M; Chatterjee, M

    2000-09-01

    Vanadium, a non-platinum group metal and dietary micronutrient, is now proving to act as a promising antitumor agent. The present study was conducted to ascertain its antineoplastic potential against an experimental mammary carcinogenesis. Female Sprague-Dawley rats, at 50 days of age, were treated with 7,12-dimethylbenz(a)anthracene (DMBA) (0.5 mg/100 g body weight) by a single tail vein injection in an oil emulsion. Vanadium (ammonium monovanadate) at the concentration of 0.5 ppm was supplemented in drinking water and given ad libitum to the experimental group immediately after the carcinogen treatment and it continued until the termination of the study (24 weeks for histological and biochemical observations and 35 weeks for morphological findings). It was found that vanadium treatment brought about a substantial protection against DMBA-induced mammary carcinogenesis. This was evident from histological findings that showed no sign of hyperplasia or abnormality after vanadium treatment. There was a significant reduction in incidence (P < 0.05), total number, multiplicity (P < 0.01) and size of palpable mammary tumors and delay in mean latency period of tumor appearance (P < 0.001) following vanadium supplementation compared to DMBA control. From the cumulative results of various hepatic biochemical indices namely, lipid peroxidation, reduced glutathione level, superoxide dismutase activity, cytochrome P450 content and glutathione S-transferase activity, the anticarcinogenic potential of vanadium was well reflected through stabilization of these parameters. Results of the study indicate that the anticarcinogenic activity of vanadium during DMBA-initiated mammary carcinogenesis is mediated through alteration of hepatic antioxidant status as well as modulation of phase I and II drug metabolizing enzymes. On the basis of the observed results, vanadium can be considered as a readily available, promising and novel cancer chemopreventive agent. PMID:11097089

  16. Potential Role of Epigenetic Mechanisms in the Regulation of Drug Metabolism and Transport

    PubMed Central

    Ingelman-Sundberg, Magnus; Zhong, Xiao-Bo; Hankinson, Oliver; Beedanagari, Sudheer; Yu, Ai-Ming; Peng, Lai

    2013-01-01

    This is a report of a symposium on the potential role of epigenetic mechanisms in the control of drug disposition sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the Experimental Biology 2013 meeting in Boston, MA, April 21, 2013. Epigenetics is a rapidly evolving area, and recent studies have revealed that expression of drug-metabolizing enzymes and transporters is regulated by epigenetic factors, including histone modification, DNA methylation, and noncoding RNAs. The symposium speakers provided an overview of genetic and epigenetic mechanisms underlying variable drug metabolism and drug response, as well as the implications for personalized medicine. Considerable insight into the epigenetic mechanisms in differential regulation of the dioxin-inducible drug and carcinogen-metabolizing enzymes CYP1A1 and 1B1 was provided. The role of noncoding microRNAs in the control of drug metabolism and disposition through targeting of cytochrome P450 (P450) enzymes and ATP-binding cassette membrane transporters was discussed. In addition, potential effects of xenobiotics on chromatin interactions and epigenomics, as well as the possible role of long noncoding RNAs in regulation of P450s during liver maturation were presented. PMID:23918665

  17. Leflunomide Induces Pulmonary and Hepatic CYP1A Enzymes via Aryl Hydrocarbon Receptor.

    PubMed

    Patel, Ananddeep; Zhang, Shaojie; Paramahamsa, Maturu; Jiang, Weiwu; Wang, Lihua; Moorthy, Bhagavatula; Shivanna, Binoy

    2015-12-01

    Emerging evidence indicates that the aryl hydrocarbon receptor (AhR) plays a crucial role in normal physiologic homeostasis. Additionally, aberrant AhR signaling leads to several pathologic states in the lung and liver. Activation of AhR transcriptionally induces phase I (CYP1A) detoxifying enzymes. Although the effects of the classic AhR ligands such as 3-methylcholanthrene and dioxins on phase 1 enzymes are well studied in rodent lung, liver, and other organs, the toxicity profiles limit their use as therapeutic agents in humans. Hence, there is a need to identify and investigate nontoxic AhR ligands not only to understand the AhR biology but also to develop the AhR as a clinically relevant therapeutic target. Leflunomide is a Food and Drug Administration-approved drug in humans that is known to have AhR agonist activity in vitro. Whether it activates AhR and induces phase 1 enzymes in vivo is unknown. Therefore, we tested the hypothesis that leflunomide will induce pulmonary and hepatic CYP1A enzymes in C57BL/6J wild-type mice, but not in AhR-null mice. We performed real-time reverse-transcription polymerase chain reaction analyses for CYP1A1/2 mRNA expression, western blot assays for CYP1A1/2 protein expression, and ethoxyresorufinO-deethylase assay for CYP1A1 catalytic activity. Leflunomide increased CYP1A1/A2 mRNA, protein, and enzymatic activities in wild-type mice. In contrast, leflunomide failed to increase pulmonary and hepatic CYP1A enzymes in AhR-null mice. In conclusion, we provide evidence that leflunomide induces pulmonary and hepatic CYP1A enzymes via the AhR. PMID:26417045

  18. Cimetidine as an inhibitor of drug metabolism: therapeutic implications and review of the literature.

    PubMed

    Bauman, J H; Kimelblatt, B J

    1982-05-01

    Cimetidine has been reported to decrease the biotransformation of drugs metabolized by the MFOE system. Additionally, cimetidine decreases liver blood flow and increases the bioavailability of drugs with high hepatic extraction ratios. Patients receiving cimetidine in conjunction with drugs known to interact with cimetidine in conjunction with drugs known to interact with cimetidine are at risk of experiencing toxicity. When appropriate, reducing the dosage of these agents or switching to an alternative drug will minimize the incidence of side effects. Clinicians should be suspicious if patients experience exaggerated drug effects when cimetidine therapy is begun. PMID:6123423

  19. Efficient drug metabolism strategy based on microsome-mesoporous organosilica nanoreactors.

    PubMed

    Fang, Xiaoni; Zhang, Peng; Qiao, Liang; Feng, Xiaoyan; Zhang, Xiangmin; Girault, Hubert H; Liu, Baohong

    2014-11-01

    A rapid and accurate in vitro drug metabolism strategy has been proposed based on the design of a biomimetic nanoreactor composed of amino-functionalized periodic mesoporous organosilica (NH2-PMO) and microsomes. The amphiphilic nature and positive charge of NH2-PMO make it highly suited for the immobilization of hydrophobic and negatively charged microsomes to form nanoreactors, which can in turn extract substrates from solutions. Such nanoreactors provide a suitable environment to confine multiple enzymes and substrates with high local concentrations, as well as to maintain their catalytic activities for rapid and highly effective drug metabolic reactions. Coupled with high-performance liquid chromatography-mass spectrometry analysis, the metabolites of nifedipine and testosterone were quantitatively characterized, and the reaction kinetics was evaluated. Both the metabolism conversion and reaction rate were significantly improved with the NH2-PMO nanoreactors compared to bulk reactions. This strategy is simple and cost-effective for promising advances in biomimetic metabolism study. PMID:25313798

  20. Proteomic analysis for the impact of hypercholesterolemia on expressions of hepatic drug transporters and metabolizing enzymes.

    PubMed

    Liu, Yan; Pu, Qiang-Hong; Wu, Ming-Jun; Yu, Chao

    2016-10-01

    1. Our objective is to investigate the alterations of hepatic drug transporters and metabolizing enzymes in hypercholesterolemia. Male Sprague-Dawley rats were fed high-cholesterol chows for 8 weeks to induce hypercholesterolemia. Protein levels of hepatic drug transporters and metabolizing enzymes were analyzed by iTRAQ labeling coupled with LC TRIPLE-TOF. 2. Total 239 differentially expressed proteins were identified using proteomic analysis. Among those, protein levels of hepatic drug transporters (MRP2, ABCD3, OAT2, SLC25A12, SCL38A3, SLC2A2 and SLC25A5) and metabolizing enzymes (CYP2B3, CYP2C7, CYP2C11, CYP2C13, CYP4A2 and UGT2B) were markedly reduced, but the levels of CYP2C6 and CYP2E1 were increased in hypercholesterolemia group compared to control. Decreased expressions of drug transporters MRP2 and OAT2 were further confirmed by real time quantitative PCR (RT-qPCR) and western blot. 3. Ingenuity pathway analysis revealed that these differentially expressed proteins were regulated by various signaling pathways including nuclear receptors and inflammatory cytokines. One of the nuclear receptor candidates, liver X receptor alpha (LXRα), was further validated by RT-qPCR and western blot. Additionally, LXRα agonist T0901317 rescued the reduced expressions of MRP2 and OAT2 in HepG2 cells in hypercholesterolemic serum treatment. 4. Our present results indicated that hypercholesterolemia affected the expressions of various drug transporters and metabolizing enzymes in liver via nuclear receptors pathway. Especially, decreased function of LXRα contributes to the reduced expressions of MRP2 and OAT2. PMID:26887802

  1. Acute effects of oral and intravenous ethanol on rat hepatic enzyme activities.

    PubMed

    Stifel, F B; Greene, H L; Lufkin, E G; Wrensch, M R; Hagler, L; Herman, R H

    1976-05-28

    1. Oral administration of ethanol (3 ml) of 95% in 12 ml total volume over a two day period) significantly decrease plasma glucose and insulin levels and the activities of two key gluconeogenic enzymes, pyruvate carboxylase (pyruvate: CO2 ligase (ADP), EC 6.4.1.1) and fructose diphosphatase, (D-Fru-1,6-P2 1-phosphohydrolase, EC 3.1.3.11), and one glycolytic enzyme, fructose-1,6-P2 aldolase (Fru-1,6-P2 D-glyceraldehyde-3-P lyase, EC 4.1.2.13). In each instance, the administration of 2400 mug daily of oral folate in conjuction with the ethanol prevented these alterations in carbohydrate metabolism. 2. Intravenous injection of ethanol produced a rapid decrease (within 10--15 min) in the activities of hepatic phosphofructokinase, (ATP:D-fructose-6-phosphate 6-phosphotransferase, EC 2.7.1.11), pyruvate kinase, (ATP:pyruvate phosphotransferase, EC 2.7.1.40), fructose diphosphatase and fructose-1,6-P2 aldolase. 3. Intravenous ethanol significantly increased hepatic cyclic AMP concentration approximately 60% within 10 min, while oral ethanol did not alter hepatic cyclic AMP concentrations. 4. These data confirm the known antagonism ethanol and folate and suggest that oral folate might offer a protective effect against hypoglycemia in rats receiving ethanol. PMID:179581

  2. Role of Biotransformation in Drug-Induced Toxicity: Influence of Intra- and Inter-Species Differences in Drug Metabolism

    PubMed Central

    Baillie, Thomas A.; Rettie, Allan E.

    2015-01-01

    It is now widely appreciated that drug metabolites, in addition to the parent drugs themselves, can mediate the serious adverse effects of new therapeutic agents, as a result of which there has been heightened interest in the field of drug metabolism from researchers in academia, the pharmaceutical industry, and regulatory agencies. Much progress has been made in recent years in understanding mechanisms of toxicities caused by drug metabolites, and the numerous factors that influence individual exposure to products of drug biotransformation. This review addresses some of these factors, including the role of drug-drug interactions, reactive metabolite formation, individual susceptibility, and species differences in drug disposition caused by genetic polymorphisms in drug metabolizing enzymes. Examples are provided of adverse reactions that are linked to drug metabolism, and the mechanisms underlying variability in toxic response are discussed. Finally, some future directions for research in this field are highlighted in the context of the discovery and development of new therapeutic agents. PMID:20978360

  3. Hepatic Enzyme Alterations in HIV Patients on Antiretroviral Therapy: A Case-Control Study in a Hospital Setting in Ghana

    PubMed Central

    Osakunor, Derick Nii Mensah; Obirikorang, Christian; Fianu, Vincent; Asare, Isaac; Dakorah, Mavis

    2015-01-01

    Background Diagnosing hepatic injury in HIV infection can be a herculean task for clinicians as several factors may be involved. In this study, we sought to determine the effects of antiretroviral therapy (ART) and disease progression on hepatic enzymes in HIV patients. Methods A case-control study conducted from January to May 2014 at the Akwatia Government Hospital, Eastern region, Ghana, The study included 209 HIV patients on ART (designated HIV-ART) and 132 ART-naive HIV patients (designated HIV-Controls). Data gathered included demography, clinical history and results of blood tests for hepatic enzymes. We employed the Fisher’s, Chi-square, unpaired t-test and Pearson’s correlation in analysis, using GraphPad Prism and SPSS. A P value < 0.05 was considered significant. Results Median CD4 lymphocyte count of HIV-ART participants (604.00 cells/mm3) was higher than that of HIV-Controls (491.50 cells/mm3; P = 0.0005). Mean values of ALP, ALT, AST and GGT did not differ between the two groups compared (P > 0.05). There was a significant positive correlation between hepatic enzymes (ALP, ALT, AST and GGT) for both groups (p < 0.01 each). Duration of ART correlated positively with ALT (p < 0.05). The effect size of disease progression on hepatic enzymes for both groups was small. Conclusion Antiretroviral therapy amongst this population has minimal effects on hepatic enzymes and does not suggest modifications in therapy. Hepatic injury may occur in HIV, even in the absence of ART and other traditional factors. Monitoring of hepatic enzymes is still important in HIV patients. PMID:26247879

  4. Hepatic biotransformation and antioxidant enzyme activities in Mediterranean fish from different habitat depths.

    PubMed

    Ribalta, C; Sanchez-Hernandez, J C; Sole, M

    2015-11-01

    Marine fish are threatened by anthropogenic chemical discharges. However, knowledge on adverse effects on deep-sea fish or their detoxification capabilities is limited. Herein, we compared the basal activities of selected hepatic detoxification enzymes in several species (Solea solea, Dicentrarchus labrax, Trachyrhynchus scabrus, Mora moro, Cataetix laticeps and Alepocehalus rostratus) collected from the coast, middle and lower slopes of the Blanes Canyon region (Catalan continental margin, NW Mediterranean Sea). The xenobiotic-detoxifying enzymes analysed were the phase-I carboxylesterases (CbEs), and the phase-II conjugation activities uridine diphosphate glucuronyltransferase (UDPGT) and glutathione S-transferase (GST). Moreover, some antioxidant enzyme activities, i.e., catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR), were also included in this comparative study. Because CbE activity is represented by multiple isoforms, the substrates α-naphthyl acetate (αNA) and ρ-nitrophenyl acetate (ρNPA) were used in the enzyme assays, and in vitro inhibition kinetics with dichlorvos were performed to compare interspecific CbE sensitivity. Activity of xenobiotic detoxification enzymes varied among the species, following a trend with habitat depth and body size. Thus, UDPGT and some antioxidant enzyme activities decreased in fish inhabiting lower slopes of deep-sea, whereas UDPGT and αNA-CbE activities were negatively related to fish size. A trend between CbE activities and the IC50 values for dichlorvos suggested S. solea and M. moro as potentially more sensitive to anticholinesterasic pesticides, and T. scabrus as the most resistant one. A principal component analysis considering all enzyme activities clearly identified the species but this grouping was not related to habitat depth or phylogeny. Although these results can be taken as baseline levels of the main xenobiotic detoxification enzymes in Mediterranean fish, further research is

  5. Hepatitis

    MedlinePlus

    ... Got Homework? Here's Help White House Lunch Recipes Hepatitis KidsHealth > For Kids > Hepatitis Print A A A ... an important digestive liquid called bile . What Is Hepatitis? Hepatitis is an inflammation (say: in-fluh-MAY- ...

  6. Acute Liver Injury Induces Nucleocytoplasmic Redistribution of Hepatic Methionine Metabolism Enzymes

    PubMed Central

    Delgado, Miguel; Garrido, Francisco; Pérez-Miguelsanz, Juliana; Pacheco, María; Partearroyo, Teresa; Pérez-Sala, Dolores

    2014-01-01

    Abstract Aims: The discovery of methionine metabolism enzymes in the cell nucleus, together with their association with key nuclear processes, suggested a putative relationship between alterations in their subcellular distribution and disease. Results: Using the rat model of d-galactosamine intoxication, severe changes in hepatic steady-state mRNA levels were found; the largest decreases corresponded to enzymes exhibiting the highest expression in normal tissue. Cytoplasmic protein levels, activities, and metabolite concentrations suffered more moderate changes following a similar trend. Interestingly, galactosamine treatment induced hepatic nuclear accumulation of methionine adenosyltransferase (MAT) α1 and S-adenosylhomocysteine hydrolase tetramers, their active assemblies. In fact, galactosamine-treated livers showed enhanced nuclear MAT activity. Acetaminophen (APAP) intoxication mimicked most galactosamine effects on hepatic MATα1, including accumulation of nuclear tetramers. H35 cells that overexpress tagged-MATα1 reproduced the subcellular distribution observed in liver, and the changes induced by galactosamine and APAP that were also observed upon glutathione depletion by buthionine sulfoximine. The H35 nuclear accumulation of tagged-MATα1 induced by these agents correlated with decreased glutathione reduced form/glutathione oxidized form ratios and was prevented by N-acetylcysteine (NAC) and glutathione ethyl ester. However, the changes in epigenetic modifications associated with tagged-MATα1 nuclear accumulation were only prevented by NAC in galactosamine-treated cells. Innovation: Cytoplasmic and nuclear changes in proteins that regulate the methylation index follow opposite trends in acute liver injury, their nuclear accumulation showing potential as disease marker. Conclusion: Altogether these results demonstrate galactosamine- and APAP-induced nuclear accumulation of methionine metabolism enzymes as active oligomers and unveil the implication of

  7. Comparison of Enzyme Immunoassays for Detection of Antibodies to Hepatitis D Virus in Serum.

    PubMed

    Chow, Siu-Kei; Atienza, Ederlyn E; Cook, Linda; Prince, Harry; Slev, Patricia; Lapé-Nixon, Mary; Jerome, Keith R

    2016-08-01

    Serology remains critical for diagnosing hepatitis D virus (HDV) infection, which affects 15 to 20 million people worldwide, but the literature on characterizing commercial enzyme immunoassays (EIAs) dates back to 15 years ago. We evaluated 2 commercial EIAs currently available for detecting anti-HDV antibodies. The DiaSorin assay demonstrated 100% sensitivity and specificity. Using a modified cutoff value, the Cusabio assay demonstrated a sensitivity of 81.3% and specificity of 90.9%. Our data show that recently developed EIAs are reliable for anti-HDV antibody detection. PMID:27280621

  8. Drug metabolism and clearance system in tumor cells of patients with multiple myeloma

    PubMed Central

    Hassen, Wafa; Kassambara, Alboukadel; Reme, Thierry; Sahota, Surinder; Seckinger, Anja; Vincent, Laure; Cartron, Guillaume; Moreaux, Jérôme; Hose, Dirk; Klein, Bernard

    2015-01-01

    Resistance to chemotherapy is a major limitation of cancer treatments with several molecular mechanisms involved, in particular altered local drug metabolism and detoxification process. The role of drug metabolism and clearance system has not been satisfactorily investigated in Multiple Myeloma (MM), a malignant plasma cell cancer for which a majority of patients escapes treatment. The expression of 350 genes encoding for uptake carriers, xenobiotic receptors, phase I and II Drug Metabolizing Enzymes (DMEs) and efflux transporters was interrogated in MM cells (MMCs) of newly-diagnosed patients in relation to their event free survival. MMCs of patients with a favourable outcome have an increased expression of genes coding for xenobiotic receptors (RXRα, LXR, CAR and FXR) and accordingly of their gene targets, influx transporters and phase I/II DMEs. On the contrary, MMCs of patients with unfavourable outcome displayed a global down regulation of genes coding for xenobiotic receptors and the downstream detoxification genes but had a high expression of genes coding for ARNT and Nrf2 pathways and ABC transporters. Altogether, these data suggests ARNT and Nrf2 pathways could be involved in MM primary resistance and that targeting RXRα, PXR, LXR and FXR through agonists could open new perspectives to alleviate or reverse MM drug resistance. PMID:25669983

  9. Xenobiotic-sensing nuclear receptors involved in drug metabolism: a structural perspective

    PubMed Central

    Wallace, Bret D.; Redinbo, Matthew R.

    2016-01-01

    Xenobiotic compounds undergo a critical range of biotransformations performed by the phase I, II, and III drug-metabolizing enzymes. The oxidation, conjugation, and transportation of potentially harmful xenobiotic and endobiotic compounds achieved by these catalytic systems are significantly regulated, at the gene expression level, by members of the nuclear receptor (NR) family of ligand-modulated transcription factors. Activation of NRs by a variety of endo- and exogenous chemicals are elemental to induction and repression of drug-metabolism pathways. The master xenobiotic sensing NRs, the promiscuous pregnane X receptor and less-promiscuous constitutive androstane receptor are crucial to initial ligand recognition, jump-starting the metabolic process. Other receptors, including farnesoid X receptor, vitamin D receptor, hepatocyte nuclear factor 4 alpha, peroxisome proliferator activated receptor, glucocorticoid receptor, liver X receptor, and RAR-related orphan receptor, are not directly linked to promiscuous xenobiotic binding, but clearly play important roles in the modulation of metabolic gene expression. Crystallographic studies of the ligand-binding domains of nine NRs involved in drug metabolism provide key insights into ligand-based and constitutive activity, coregulator recruitment, and gene regulation. Structures of other, noncanonical transcription factors also shed light on secondary, but important, pathways of control. Pharmacological targeting of some of these nuclear and atypical receptors has been instituted as a means to treat metabolic and developmental disorders and provides a future avenue to be explored for other members of the xenobiotic-sensing NRs. PMID:23210723

  10. Altered mRNA expression of hepatic lipogenic enzyme and PPARalpha in rats fed dietary levan from Zymomonas mobilis.

    PubMed

    Kang, Soon Ah; Hong, Kyunghee; Jang, Ki-Hyo; Kim, Yun-Young; Choue, Ryowon; Lim, Yoongho

    2006-06-01

    Levan or high molecular beta-2,6-linked fructose polymer is produced extracellularly from sucrose-based substrates by bacterial levansucrase. In the present study, to investigate the effect of levan feeding on serum leptin, hepatic lipogenic enzyme and peroxisome proliferation-activated receptor (PPAR) alpha expression in high-fat diet-induced obese rats, 4-week-old Sprague-Dawley male rats were fed high-fat diet (beef tallow, 40% of calories as fat), and, 6 weeks later, the rats were fed 0%, 1%, 5% or 10% levan-supplemented diets for 4 weeks. Serum leptin and insulin level were dose dependently reduced in levan-supplemented diet-fed rats. The mRNA expressions of hepatic fatty acid synthase and acetyl CoA carboxylase, which are the key enzymes in fatty acid synthesis, were down-regulated by dietary levan. However, dietary levan did not affect the gene expression of hepatic malic enzyme, phosphatidate phosphohydrolase and HMG CoA reductase. Also, the lipogenic enzyme gene expression in the white adipose tissue (WAT) was not affected by the diet treatments. However, hepatic PPARalpha mRNA expression was dose dependently up-regulated by dietary levan, whereas PPARgamma in the WAT was not changed. The results suggest that the in vivo hypolipidemic effect of dietary levan, including anti-obesity and lipid-lowering, may result from the inhibition of lipogenesis and stimulation of lipolysis, accompanied with regulation of hepatic lipogenic enzyme and PPARalpha gene expression. PMID:16214330

  11. Intestinal detoxification limits the activation of hepatic pregnane X receptor by lithocholic acid.

    PubMed

    Owen, Bryn M; Milona, Alexandra; van Mil, Saskia; Clements, Peter; Holder, Julie; Boudjelal, Mohamed; Cairns, William; Parker, Malcolm; White, Roger; Williamson, Catherine

    2010-01-01

    The intestinal-derived secondary bile acid (BA) lithocholic acid (LCA) is hepatotoxic and is implicated in the pathogenesis of cholestatic diseases. LCA is an endogenous ligand of the xenobiotic nuclear receptor pregnane X receptor (PXR), but there is currently no consensus on the respective roles of hepatic and intestinal PXR in mediating protection against LCA in vivo. Under the conditions reported here, we show that mice lacking Pxr are resistant to LCA-mediated hepatotoxicity. This unexpected phenotype is found in association with enhanced urinary BA excretion and elevated basal expression of drug metabolism enzymes and the hepatic sulfate donor synthesis enzyme Papss2 in Pxr(-/-) mice. By subsequently comparing molecular responses to dietary and intraperitoneal administration of LCA, we made two other significant observations: 1) LCA feeding induces intestinal, but not hepatic, drug-metabolizing enzymes in a largely Pxr-independent manner; and 2) in contrast to LCA feeding, bypassing first-pass gut transit by intraperitoneal administration of LCA did induce hepatic detoxification machinery and in a Pxr-dependent manner. These data reconcile important discrepancies in the reported molecular responses to this BA and suggest that Pxr plays only a limited role in mediating responses to gut-derived LCA. Furthermore, the route of administration must be considered in the future planning and interpretation of experiments designed to assess hepatic responses to BAs, orally administered pharmaceuticals, and dietary toxins. PMID:19797606

  12. Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6.

    PubMed

    Kretzschmar, Michael; Krüger, Antie; Schirrmeister, Wulf

    2003-06-01

    The hepatic ischemia-reperfusion syndrome was investigated in 28 patients undergoing elective partial liver resection with intraoperative occlusion of hepatic inflow (Pringle maneuver) using the technique of liver vein catheterization. Hepatic venous oxygen saturation (ShvO2) was monitored continuously up to 24 hours after surgery. Aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase, pseudocholinesterase, alpha-glutathione S-transferase, reduced and oxidized glutathione, procalcitonine, and interleukin-6 were serially measured both before and after Pringle maneuver during the resection and postoperatively in arterial and/or hepatic venous blood. ShvO2 measurement demonstrated that peri- and postoperative management was suitable to maintain an optimal hepatic oxygen supply. As expected, we were able to demonstrate a typical enzyme pattern of postischemic liver injury. There was a distinct decrease of reduced glutathione levels both in arterial and hepatic venous plasma after LR accompanied by a strong increase in oxidized glutathione concentration during the phase of reperfusion. We observed increases in procalcitonin and interleukin-6 levels both in arterial and hepatic venous blood after declamping. Our data support the view that liver resection in man under conditions of inflow occlusion resulted in ischemic lesion of the liver (loss of glutathione synthesizing capacity with disturbance of protection against oxidative stress) and an additional impairment during reperfusion (liberation of reactive oxygen species, local and systemic inflammation reaction with cytokine production). Additionally, we found some evidence for the assumption that the liver has an export function for reduced glutathione into plasma in man. PMID:12877355

  13. Hepatic Expression of Detoxification Enzymes Is Decreased in Human Obstructive Cholestasis Due to Gallstone Biliary Obstruction

    PubMed Central

    Chai, Jin; Feng, Xinchan; Zhang, Liangjun; Chen, Sheng; Cheng, Ying; He, Xiaochong; Yang, Yingxue; He, Yu; Wang, Huaizhi; Wang, Rongquan; Chen, Wensheng

    2015-01-01

    Background & Aims Levels of bile acid metabolic enzymes and membrane transporters have been reported to change in cholestasis. These alterations (e.g. CYP7A1 repression and MRP4 induction) are thought to be adaptive responses that attenuate cholestatic liver injury. However, the molecular mechanisms of these adaptive responses in human obstructive cholestasis due to gallstone biliary obstruction remain unclear. Methods We collected liver samples from cholestatic patients with biliary obstruction due to gallstones and from control patients without liver disease (n = 22 per group). The expression levels of bile acid synthetic and detoxification enzymes, membrane transporters, and the related nuclear receptors and transcriptional factors were measured. Results The levels of bile acid synthetic enzymes, CYP7B1 and CYP8B1, and the detoxification enzyme CYP2B6 were increased in cholestatic livers by 2.4-fold, 2.8-fold, and 1.9-fold, respectively (p<0.05). Conversely, the expression levels of liver detoxification enzymes, UGT2B4/7, SULT2A1, GSTA1-4, and GSTM1-4, were reduced by approximately 50% (p<0.05) in human obstructive cholestasis. The levels of membrane transporters, OSTβ and OCT1, were increased 10.4-fold and 1.8-fold, respectively, (p<0.05), whereas those of OSTα, ABCG2 and ABCG8 were all decreased by approximately 40%, (p<0.05) in human cholestatic livers. Hepatic nuclear receptors, VDR, HNF4α, RXRα and RARα, were induced (approximately 2.0-fold, (p<0.05) whereas FXR levels were markedly reduced to 44% of control, (p<0.05) in human obstructive cholestasis. There was a significantly positive correlation between the reduction in FXR mRNA and UGT2B4/7, SULT2A1, GSTA1, ABCG2/8 mRNA levels in livers of obstructive cholestatic patients (p<0.05). Conclusions The levels of hepatic detoxification enzymes were significantly decreased in human obstructive cholestasis, and these decreases were positively associated with a marked reduction of FXR levels. These findings

  14. Hepatic microsomal drug oxidation and electron transport in newborn infants.

    PubMed

    Aranda, J V; MacLeod, S M; Renton, K W; Eade, N R

    1974-10-01

    Many drugs require oxidative metabolism for termination of action and/or for elimination from the body. Many oxidative reactions are catalyzed by hepatic microsomal enzymes. The activities of various drug-metabolizing enzymes, namely, NADPH cytochrome c reductase, NADPH oxidase, aminopyrine-N-demethylase, and analine P-hydroxylase, and the content of cytochrome P-450, were measured in hepatic microsomes obtained from seven newborn infants and four adult patients. The results in the newborn infant show increasing activities of these enzymes (except aminopyrine-N-demethylase) related to advancing age. Good correlation between three components of the hepatic microsomal mixed function oxidase system and aniline p-hydroxylase was established, whereas only NADPH oxidation correlated with aminopyrine N-demethylation. The rate of substrate or drug oxidation and the activities of the components of the microsomal electron transport pathway were lower than comparable values in the adult. The data demonstrate a possible biochemical basis for the transient deficiency in drug metabolism seen in newborn infants. PMID:4155438

  15. Hepatic cell lines for drug hepatotoxicity testing: limitations and strategies to upgrade their metabolic competence by gene engineering.

    PubMed

    Donato, M Teresa; Jover, Ramiro; Gómez-Lechón, M José

    2013-11-01

    One key issue in the pharmaceutical development of new compounds is knowledge on metabolism, the enzymes involved and the potential hepatotoxicity of a drug. Primary cultured hepatocytes are a valuable in vitro model for drug metabolism studies. However, human hepatocytes show phenotypic instability and have restricted accessibility and high batch-to-batch functional variability, which seriously complicates their use in routine testing. Therefore, several liver-derived cell models have been developed for drug metabolism and hepatotoxicity screening to circumvent these drawbacks. Hepatoma cell lines offer important advantages, availability, an unlimited life span and a stable phenotype, thus rendering them suitable models for such studies. However, currently available human hepatoma cell lines are not a good alternative to cultured hepatocytes as they show very limited expression for most drug-metabolising enzymes. Other approaches have been developed to generate immortalised hepatic cells with metabolic competence (use of plasmids encoding immortalising genes to transform human hepatocytes, cell lines obtained from transgenic animals, hepatocytomes or hydrid cells). Recombinant models heterologously expressing cytochrome P450 enzymes in hepatoma cells have also been generated, and are widely used in drug metabolism and toxicity evaluations. In recent years, new approaches to up-regulate the expression of drug-biotransformation enzymes in human cell lines (i.e., transfection with the expression vectors encoding key hepatic transcription factors) have also been investigated. This paper reviews the features of liver-derived cell lines, their suitability for drug metabolism and hepatotoxicity studies, and the state-of-the-art strategies pursued to generate metabolically competent hepatic cell lines. PMID:24160292

  16. Liver Enzymes in Children with beta-Thalassemia Major: Correlation with Iron Overload and Viral Hepatitis

    PubMed Central

    Salama, Khaled M.; Ibrahim, Ola M.; Kaddah, Ahmed M.; Boseila, Samia; Ismail, Leila Abu; Hamid, May M. Abdel

    2015-01-01

    BACKGROUND: Beta Thalassemia is the most common chronic hemolytic anemia in Egypt (85.1%) with an estimated carrier rate of 9-10.2%. Injury to the liver, whether acute or chronic, eventually results in an increase in serum concentrations of Alanine transaminase (ALT) and Aspartate transaminase (AST). AIM: Evaluating the potentiating effect of iron overload & viral hepatitis infection on the liver enzymes. PATIENTS AND METHODS: Eighty (80) thalassemia major patients were studied with respect to liver enzymes, ferritin, transferrin saturation, HBsAg, anti-HCV antibody and HCV-PCR for anti-HCV positive patients. RESULTS: Fifty % of the patients were anti-HCV positive and 55% of them were HCV-PCR positive. Patients with elevated ALT and AST levels had significantly higher mean serum ferritin than those with normal levels. Anti-HCV positive patients had higher mean serum ferritin, serum ALT, AST and GGT levels and higher age and duration of blood transfusion than the negative group. HCV-PCR positive patients had higher mean serum ferritin and serum ALT and also higher age and duration of blood transfusion than the negative group. CONCLUSION: Iron overload is a main leading cause of elevated liver enzymes, and presence of HCV infection is significantly related to the increased iron overload. PMID:27275237

  17. Pathogenesis of Lactobacillus casei-induced polyarthritis in Lewis rats: 2. Time related changes in organ weights and liver enzymes.

    PubMed

    Wilson, D; O'Byrne, E M; Blancuzzi, V; Schlosser, M; Borman, C H; DiPasquale, G

    1993-01-01

    Hepatic enzymes and organ weights were measured in LEW/N female rats during the acute and the chronic phases of L. casei-induced arthritis on day 3 and days 30 and 59, respectively. In the acute phase, day 3, adrenal and spleen weights were increased and thymus weights were decreased in L. casei arthritic rats as compared to normal control rats. Adrenal, liver, kidney, spleen and thymus weights of arthritic rats were in the normal range on days 30 and 59. Liver cytochrome P450, aminopyrine N-demethylase and analine hydroxylase were reduced in livers of L. casei-treated rats on day 3 as compared to normal controls. On days 30 and 59 hepatic enzymes in L. casei-arthritic rats were in the normal range. Unlike adjuvant arthritis in which changes in liver enzymes alter drug metabolism; after the acute onset of L. casei-induced arthritis, hepatic enzymes return to the normal range. PMID:8273567

  18. DrugBank 4.0: shedding new light on drug metabolism.

    PubMed

    Law, Vivian; Knox, Craig; Djoumbou, Yannick; Jewison, Tim; Guo, An Chi; Liu, Yifeng; Maciejewski, Adam; Arndt, David; Wilson, Michael; Neveu, Vanessa; Tang, Alexandra; Gabriel, Geraldine; Ly, Carol; Adamjee, Sakina; Dame, Zerihun T; Han, Beomsoo; Zhou, You; Wishart, David S

    2014-01-01

    DrugBank (http://www.drugbank.ca) is a comprehensive online database containing extensive biochemical and pharmacological information about drugs, their mechanisms and their targets. Since it was first described in 2006, DrugBank has rapidly evolved, both in response to user requests and in response to changing trends in drug research and development. Previous versions of DrugBank have been widely used to facilitate drug and in silico drug target discovery. The latest update, DrugBank 4.0, has been further expanded to contain data on drug metabolism, absorption, distribution, metabolism, excretion and toxicity (ADMET) and other kinds of quantitative structure activity relationships (QSAR) information. These enhancements are intended to facilitate research in xenobiotic metabolism (both prediction and characterization), pharmacokinetics, pharmacodynamics and drug design/discovery. For this release, >1200 drug metabolites (including their structures, names, activity, abundance and other detailed data) have been added along with >1300 drug metabolism reactions (including metabolizing enzymes and reaction types) and dozens of drug metabolism pathways. Another 30 predicted or measured ADMET parameters have been added to each DrugCard, bringing the average number of quantitative ADMET values for Food and Drug Administration-approved drugs close to 40. Referential nuclear magnetic resonance and MS spectra have been added for almost 400 drugs as well as spectral and mass matching tools to facilitate compound identification. This expanded collection of drug information is complemented by a number of new or improved search tools, including one that provides a simple analyses of drug-target, -enzyme and -transporter associations to provide insight on drug-drug interactions. PMID:24203711

  19. Differential regulation of hepatic enzymes by polycyclic aromatic hydrocarbons and glucocorticoids

    SciTech Connect

    Smith, J.A.; Linder, M.W.; Fernandez, D.; Prough, R.A. )

    1991-03-15

    A putative glucocorticoid (GC) response element has been identified within the first intron of the P450IA1 gene and is apparently necessary for GC-dependent potentiation of polycyclic aromatic hydrocarbon (PAH) induction of P450IA1. In cultured rat hepatocytes, the synthetic GC, dexamethasone (DEX), potentiated PAH induction of both P450IA1 and glutathione S-transferase protein and mRNA. However, DEX caused a small decrease in PAH-dependent induction of NAD(P)H:quinone oxidoreductase (QOR) subunit protein and mRNA in culture. The potentiation of 3-methylcholanthrene (MC) dependent induction of hepatic P450IA1, GST and QOR by low doses of DEX was evaluated in neonatal and adult rats. In neonates, MC induction was potentiated 2-, 1.5-, and 1.4-fold for P450IA1, GST, and QOR activities, respectively, by DEX. However, in adult rats, DEX potentiated MC induction of P450IA1 activity, but repressed MC induction of GST and QOR. Western immunoanalysis and Northern analysis indicated that the changes in these activities were associated with parallel changes in the levels of immunoreactive proteins and mRNA. Glucocorticoids may have an age-dependent influence on the induction of hepatic enzymes by PAH possibly involving other regulatory factors, in addition to Ah and GC receptors.

  20. Role of Cytochrome P450 Monooxygenase in Carcinogen and Chemotherapeutic Drug Metabolism.

    PubMed

    Wahlang, B; Falkner, K Cameron; Cave, Matt C; Prough, Russell A

    2015-01-01

    The purpose of this chapter is to provide insight into which human cytochromes P450 (CYPs) may be involved in metabolism of chemical carcinogens and anticancer drugs. A historical overview of this field and the development of literature using relevant animal models and expressed human CYPs have provided information about which specific CYPs may be involved in carcinogen metabolism. Definition of the biochemical properties of CYP activity came from several groups who studied the reaction stoichiometry of butter yellow and benzo[α]pyrene, including their role in induction of these enzyme systems. This chapter will list as much as is known about the human CYPs involved in carcinogen and anticancer drug metabolism, as well as summarize studies with rodent CYPs. A review of three major classes of anticancer drugs and their metabolism in humans is covered for cyclophosphamide, procarbazine, and anthracycline antibiotics, cancer chemotherapeutic compounds extensively metabolized by CYPs. The emerging information about human CYP gene polymorphisms as well as other enzymes involved in foreign compound metabolism provides considerable information about how these genetic variants affect carcinogen and anticancer drug metabolism. With information available from individual's genomic sequences, consideration of populations who may be at risk due to environmental exposure to carcinogens or how to optimize their cancer therapy regimens to enhance efficacy of the anticancer drugs appears to be an important field of study to benefit individuals in the future. PMID:26233902

  1. Alterations in the activities of hepatic plasma-membrane and microsomal enzymes during liver regeneration.

    PubMed Central

    Deliconstantinos, G; Ramantanis, G

    1983-01-01

    A marked increase in the activities of rat liver plasma-membrane (Na+ + K+)-stimulated ATPase and microsomal Ca2+-stimulated ATPase was observed 18h after partial hepatectomy. Lipid analyses for both membrane preparations reveal that in partially hepatectomized rats the cholesterol and sphingomyelin content are decreased with a subsequent decrease in the cholesterol/phospholipid molar ratio compared with those of sham-operated animals. Changes in the allosteric properties of plasma-membrane (Na+ + K+)-stimulated ATPase by F- (as reflected by changes in the Hill coefficient) indicated a fluidization of the lipid bilayer of both membrane preparations in 18 h-regenerating liver. The amphipathic dodecyl glucoside incorporated into the hepatic plasma membranes evoked a marked increase in the (Na+ + K+)-stimulated ATPase and 5'-nucleotidase activities. The lack of effect of the glucoside on the Lubrol-PX-solubilized 5'-nucleotidase indicates that changes in the activities of the membrane-bound enzymes caused by the glucoside are due to modulation of the membrane fluidity. Dodecyl glucoside appears to increase the membrane fluidity, evaluated through changes in the Hill coefficient for plasma-membrane (Na+ + K+)-stimulated ATPase. The biological significance of these data is discussed in terms of the differences and changes in the interaction of membrane-bound enzymes with membrane lipids during liver regeneration. PMID:6309144

  2. Virus-specific mRNA capping enzyme encoded by hepatitis E virus.

    PubMed

    Magden, J; Takeda, N; Li, T; Auvinen, P; Ahola, T; Miyamura, T; Merits, A; Kääriäinen, L

    2001-07-01

    Hepatitis E virus (HEV), a positive-strand RNA virus, is an important causative agent of waterborne hepatitis. Expression of cDNA (encoding amino acids 1 to 979 of HEV nonstructural open reading frame 1) in insect cells resulted in synthesis of a 110-kDa protein (P110), a fraction of which was proteolytically processed to an 80-kDa protein. P110 was tightly bound to cytoplasmic membranes, from which it could be released by detergents. Immunopurified P110 catalyzed transfer of a methyl group from S-adenosylmethionine (AdoMet) to GTP and GDP to yield m(7)GTP or m(7)GDP. GMP, GpppG, and GpppA were poor substrates for the P110 methyltransferase. There was no evidence for further methylation of m(7)GTP when it was used as a substrate for the methyltransferase. P110 was also a guanylyltransferase, which formed a covalent complex, P110-m(7)GMP, in the presence of AdoMet and GTP, because radioactivity from both [alpha-(32)P]GTP and [(3)H-methyl]AdoMet was found in the covalent guanylate complex. Since both methyltransferase and guanylyltransferase reactions are strictly virus specific, they should offer optimal targets for development of antiviral drugs. Cap analogs such as m(7)GTP, m(7)GDP, et(2)m(7)GMP, and m(2)et(7)GMP inhibited the methyltransferase reaction. HEV P110 capping enzyme has similar properties to the methyltransferase and guanylyltransferase of alphavirus nsP1, tobacco mosaic virus P126, brome mosaic virus replicase protein 1a, and bamboo mosaic virus (a potexvirus) nonstructural protein, indicating there is a common evolutionary origin of these distantly related plant and animal virus families. PMID:11413290

  3. Hepatitis

    MedlinePlus

    ... has been associated with drinking contaminated water. Hepatitis Viruses Type Transmission Prognosis A Fecal-oral (stool to ... risk for severe disease. Others A variety of viruses can affect the liver Signs and Symptoms Hepatitis ...

  4. Evaluation of a novel chemiluminescent microplate enzyme immunoassay for hepatitis B surface antigen detection.

    PubMed

    Yang, Lin; Song, Liu-Wei; Fang, Lin-Lin; Wu, Yong; Ge, Sheng-Xiang; Li, Hui; Yuan, Quan; Zhang, Jun; Xia, Ning-Shao

    2016-02-01

    Hepatitis B virus surface antigen (HBsAg) is an important biomarker used in the diagnosis of hepatitis B virus (HBV) infection, but false-negative results are still reported in the detection of HBsAg using commercial assays. In this study, we evaluated the qualitative properties of a novel HBsAg chemiluminescence enzyme immunoassay (CLEIA) assay--WTultra. WHO standard sample dilution series and samples from low-level HBsAg carriers (<1 ng/mL) were used to evaluate the sensitivity of the WTultra assay. Boston Biomedica, Inc. (BBI) hepatitis B seroconversion panels were used to assess the ability of the WTultra assay to detect the window period. In addition, dilution series of 22 serum samples with different genotypes, serotypes and HBsAg mutations were used to assess the WTultra assay, and these were compared with other commercial assays. The lower detection limit of the WTultra assay was 0.012 IU/mL, and it showed a high sensitivity (97.52%, 95% CI, 94.95-99.00) in the detection of 282 low-level HBsAg carriers (<1 ng/mL). In samples with various HBV genotypes, serotypes and HBsAg mutations, the WTultra assay yielded 117 positive results in 132 samples, which was significantly higher than the results with the other four commercial assays (89, 83, 65 and 45, respectively, p<0.01). In the assays of mutant strains, the WTultra assay detected 82 positive results in 90 samples, which was significantly better than the results for the Hepanostika HBsAg Ultra (58 positive) and Architect (55 positive) (p<0.01) assays, which in turn were significantly better than the Murex V.3 (41 positive, p=0.026) and AxSYM V2 (29 positive, p<0.01) assays. However, in the detection of 42 samples of wild-type strains with various genotypes and serotypes, no significant differences were observed among the WTultra (35 positive), Architect (28 positive) and Hepanostika HBsAg Ultra (31 positive) assays. However, the WTultra assay detected significantly more samples than the Murex V.3 (24

  5. Enzyme immunoassay for the detection of antibody to hepatitis E virus based on synthetic peptides.

    PubMed

    Favorov, M O; Khudyakov, Y E; Fields, H A; Khudyakova, N S; Padhye, N; Alter, M J; Mast, E; Polish, L; Yashina, T L; Yarasheva, D M

    1994-02-01

    Five synthetic peptides were prepared based on the nucleotide sequence of open reading frames 2 and 3 encoded in the hepatitis E virus (HEV) genome and were used to develop an enzyme immunoassay (EIA) for the detection of anti-HEV activity in sera. Three different approaches were employed to ascertain the optimal preparation of these peptides as an immunodiagnostic reagent, including (1) a mixture of unconjugated peptides, (2) conjugating individual peptides to bovine serum albumin (BSA) followed by mixing each conjugate at various concentrations, and (3) mixing the peptides before conjugation with BSA to create an artificial antigen complex. The third method was superior in discriminating anti-HEV activity in sera previously tested by Western blot (WB). A frequency distribution of optical density values demonstrated that the peptide-based EIA was able to readily discriminate anti-HEV positive sera from sera devoid of anti-HEV activity. To confirm anti-HEV activity a neutralization test was developed using a mixture of 5 unconjugated peptides. With the exception of sera containing high levels of anti-HEV activity, all sera were neutralized greater than 50%. Strong sera required a higher dilution before a 50% neutralization was achieved. The sensitivity of the WB compared to EIA was 89.5% with and overall concordance of 94.8%. The peptide-EIA was used to determine anti-HEV activity in sera collected from various populations worldwide. In six outbreaks of ET-NANB hepatitis in various geographic regions, anti-HEV activity was demonstrated in 78-100% of cases. The peptide-EIA also detected anti-HEV activity in 14 out of 14 follow-up sera obtained 4-6 months after onset of disease and in 2 of 2 of these patients 5 yr after the acute episode. Anti-HEV activity was found in 8.5% of sera obtain from a healthy population residing in an HEV endemic region and 0.5% in two non-endemic regions (P < 0.001). These data demonstrate that a synthetic peptide-based EIA is sensitive

  6. Expression of hepatic cytochrome P450s and UDP-glucuronosyltransferases in PXR and CAR double humanized mice treated with rifampicin.

    PubMed

    Lee, Sang Yoon; Lee, Ji-Yoon; Kim, Young-Mi; Kim, Sang Kyum; Oh, Soo Jin

    2015-06-01

    Nuclear receptor humanized mice models have been developed to predict regulation of drug metabolizing enzyme by xenobiotics. However, limited information is available concerning xenobiotic-induced regulation of drug metabolizing enzymes in multiple nuclear receptor humanized mice. The present study investigated the hepatic regulation of cytochrome P450s (CYPs) and UDP-glucuronosyltransferases (UGTs) in the pregnane X receptor (PXR) and the constitutive androstane receptor double humanized mice treated with rifampicin (RIF; 10mg/kg) for 4 days. RIF increased hepatic microsomal protein and total CYP contents, and CYP reductase activity in the humanized mice, but not in normal mice. Moreover, hepatic induction of Cyp2b10, Cyp2c, and Cyp3a11 were observed only in the RIF-treated humanized mice, suggesting that the humanized mice are sensitive to RIF with respect to the regulation of the hepatic CYP system. Hepatic UGT activities using estradiol, serotonin, and mefenamic acid, but not chenodeoxycholic acid as substrates, increased in the RIF-treated humanized mice, and the glucuronidation activities of estradiol and chenodeoxycholic acid increased in RIF-treated normal mice. These results raise the possibility that a PXR-independent mechanism may be involved in hepatic regulation of UGTs by RIF. PMID:25835148

  7. Drug Metabolism by the Host and Gut Microbiota: A Partnership or Rivalry?

    PubMed

    Swanson, Hollie I

    2015-10-01

    The importance of the gut microbiome in determining not only overall health, but also in the metabolism of drugs and xenobiotics, is rapidly emerging. It is becoming increasingly clear that the gut microbiota can act in concert with the host cells to maintain intestinal homeostasis, cometabolize drugs and xenobiotics, and alter the expression levels of drug-metabolizing enzymes and transporters and the expression and activity levels of nuclear receptors. In this myriad of activities, the impact of the microbiota may be beneficial or detrimental to the host. Given that the interplay between the gut microbiota and host cells is likely subject to high interindividual variability, this work has tremendous implications for our ability to predict accurately a particular drug's pharmacokinetics and a given patient population's response to drugs. In this issue of Drug Metabolism and Disposition, a series of articles is presented that illustrate the progress and challenges that lie ahead as we unravel the intricacies associated with drug and xenobiotic metabolism by the gut microbiota. These articles highlight the underlying mechanisms that are involved and the use of in vivo and in vitro approaches that are currently available for elucidating the role of the gut microbiota in drug and xenobiotic metabolism. These articles also shed light on exciting new avenues of research that may be pursued as we consider the role of the gut microbiota as an endocrine organ, a component of the brain-gut axis, and whether the gut microbiota is an appropriate and amenable target for new drugs. PMID:26261284

  8. Drug metabolism and pharmacogenetics: the British contribution to fields of international significance

    PubMed Central

    Caldwell, John

    2006-01-01

    The branch of pharmacology we now call ‘drug metabolism', the consideration of the enzymes and procesess determining the disposition of drugs in the body, emerged in the 1840s on the continent of Europe, but British science made little or no contribution until the 1920s. From this point on, the development of the field through the 20th century was shaped to a very significant extent by a series of influential British workers, whose contributions were of global significance and who can now be seen as fathers of the subject. Since the 1950s, and gaining pace inexorably from the 1970s, the significance of drug metabolism to human therapeutics has been greatly added to by the emergence of pharmacogenetics, clinically important hereditary variation in response to drugs, which underpins the current emphasis on personalised medicine. This review examines the British contributions to both these fields through the lives of seven key contributors and attempts to place their work both in the context of its time and its lasting influence. PMID:16402125

  9. Hepatic Enzyme Decline after Pediatric Blunt Trauma: A Tool for Timing Child Abuse?

    ERIC Educational Resources Information Center

    Baxter, Amy L.; Lindberg, Daniel M.; Burke, Bonnie L.; Shults, Justine; Holmes, James F.

    2008-01-01

    Objectives: Previous research in adult patients with blunt hepatic injuries has suggested a pattern of serum hepatic transaminase concentration decline. Evaluating this decline after pediatric blunt hepatic trauma could establish parameters for estimating the time of inflicted injuries. Deviation from a consistent transaminase resolution pattern…

  10. Proteomic characterization of hepatitis C eradication: enzyme switch in the healing liver.

    PubMed

    Babudieri, S; Soddu, A; Nieddu, P; Tanca, A; Madeddu, G; Addis, M F; Pagnozzi, D; Cossu-Rocca, P; Massarelli, G; Dore, M P; Uzzau, S; Mura, M S

    2013-07-01

    Lipid pathway impairment, decrease in the antioxidant pool and downregulation in amino-acid metabolism are just some of the metabolic variations attributed to chronic HCV infection. All of them have been studied separately, mainly in animal models. Thanks to proteomic analysis we managed to describe (for the fist time to the best of our knowledge), in vivo and in humans, the metabolic alterations caused by HCV, and the recovery of the same alterations during HCV treatment. We performed proteomic analysis on liver specimens of a 28-year-old woman affected by hepatitis C genotype 1a, alcoholism and diabetes mellitus type 1, before and after antiviral treatment with pegylated interferon alpha 2b and ribavirin. The subject, thanks to a patient-tailored therapy, reached Sustained Virological Response. Throughout the treatment period the patient was monitored with subsequent biochemical, clinical and psychological examinations. The data obtained by the patient's close monitoring suggest a direct interaction between insulin resistance and an active HCV genotype 1 infection, with a leading role played by the infection, and not by insulin resistance, as demonstrated by the sharp fall of the insulin units needed per day during treatment. The proteomic analysis showed that after therapy, a downregulation of enzymes involved in amino acid metabolism, glycolysis/gluconeogenesis and alcohol catabolism takes place, the latter probably due to cessation of alcohol abuse. On the contrary, the metabolic pathways linked to metabolism of the reactive oxygen species were upregulated after therapy. Finally, a significant alteration in the pathway regulated by peroxisome proliferator-activated receptor alpha (PPARA), a major regulator of lipid metabolism in the liver, was reported. These "real time" data confirm in vivo, in humans, that during HCV infection, the pathways related to fatty acids, glucose metabolism and free radical scavenging are inhibited. The same enzyme deficit is

  11. Single-antibody in situ enzyme immunoassay for infectivity titration of hepatitis A virus.

    PubMed

    Borovec, S; Uren, E

    1997-10-01

    Hepatitis A virus (HAV) establishes a persistent infection in cultured cells, with minimal effect on host cell metabolism. As a result, the virus produces very little, if any, cytopathic effect (CPE), even with cell culture-adapted strains. This feature precludes the use of a plaque or standard endpoint assay (using CPE as an indicator of infection) for the titration of infectious virus. The radioimmunofocus assay (RIFA) is the standard method for HAV titration, though this method is labour intensive and requires the use of radioisotopes. To this end, a single-antibody in situ enzyme immunoassay (EIA) has been developed, using binding of a perioxidase-labelled monoclonal antibody to fixed cell monolayers as an indicator of infection. This novel assay is highly reproducible, can be read by eye, and is suitable for high throughput situations. Furthermore, the assay has been validated against the RIFA making it suitable for use in studies validating the safety of therapeutic biologicals for human use. PMID:9395142

  12. Defective Cytochrome P450-Catalysed Drug Metabolism in Niemann-Pick Type C Disease.

    PubMed

    Nicoli, Elena-Raluca; Al Eisa, Nada; Cluzeau, Celine V M; Wassif, Christopher A; Gray, James; Burkert, Kathryn R; Smith, David A; Morris, Lauren; Cologna, Stephanie M; Peer, Cody J; Sissung, Tristan M; Uscatu, Constantin-Daniel; Figg, William D; Pavan, William J; Vite, Charles H; Porter, Forbes D; Platt, Frances M

    2016-01-01

    Niemann-Pick type C (NPC) disease is a neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 gene. NPC is characterised by storage of multiple lipids in the late endosomal/lysosomal compartment, resulting in cellular and organ system dysfunction. The underlying molecular mechanisms that lead to the range of clinical presentations in NPC are not fully understood. While evaluating potential small molecule therapies in Npc1-/- mice, we observed a consistent pattern of toxicity associated with drugs metabolised by the cytochrome P450 system, suggesting a potential drug metabolism defect in NPC1 disease. Investigation of the P450 system in the context of NPC1 dysfunction revealed significant changes in the gene expression of many P450 associated genes across the full lifespan of Npc1-/- mice, decreased activity of cytochrome P450 reductase, and a global decrease of multiple cytochrome P450 catalysed dealkylation reactions. In vivo drug metabolism studies using a prototypic P450 metabolised drug, midazolam, confirmed dysfunction in drug clearance in the Npc1-/- mouse. Expression of the Phase II enzyme uridinediphosphate-glucuronosyltransferase (UGT) was also significantly reduced in Npc1-/- mice. Interestingly, reduced activity within the P450 system was also observed in heterozygous Npc1+/- mice. The reduced activity of P450 enzymes may be the result of bile acid deficiency/imbalance in Npc1-/- mice, as bile acid treatment significantly rescued P450 enzyme activity in Npc1-/- mice and has the potential to be an adjunctive therapy for NPC disease patients. The dysfunction in the cytochrome P450 system were recapitulated in the NPC1 feline model. Additionally, we present the first evidence that there are alterations in the P450 system in NPC1 patients. PMID:27019000

  13. Defective Cytochrome P450-Catalysed Drug Metabolism in Niemann-Pick Type C Disease

    PubMed Central

    Wassif, Christopher A.; Gray, James; Burkert, Kathryn R.; Smith, David A.; Morris, Lauren; Cologna, Stephanie M.; Peer, Cody J.; Sissung, Tristan M.; Uscatu, Constantin-Daniel; Figg, William D.; Pavan, William J.; Vite, Charles H.; Porter, Forbes D.; Platt, Frances M.

    2016-01-01

    Niemann-Pick type C (NPC) disease is a neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 gene. NPC is characterised by storage of multiple lipids in the late endosomal/lysosomal compartment, resulting in cellular and organ system dysfunction. The underlying molecular mechanisms that lead to the range of clinical presentations in NPC are not fully understood. While evaluating potential small molecule therapies in Npc1-/- mice, we observed a consistent pattern of toxicity associated with drugs metabolised by the cytochrome P450 system, suggesting a potential drug metabolism defect in NPC1 disease. Investigation of the P450 system in the context of NPC1 dysfunction revealed significant changes in the gene expression of many P450 associated genes across the full lifespan of Npc1-/- mice, decreased activity of cytochrome P450 reductase, and a global decrease of multiple cytochrome P450 catalysed dealkylation reactions. In vivo drug metabolism studies using a prototypic P450 metabolised drug, midazolam, confirmed dysfunction in drug clearance in the Npc1-/- mouse. Expression of the Phase II enzyme uridinediphosphate-glucuronosyltransferase (UGT) was also significantly reduced in Npc1-/- mice. Interestingly, reduced activity within the P450 system was also observed in heterozygous Npc1+/- mice. The reduced activity of P450 enzymes may be the result of bile acid deficiency/imbalance in Npc1-/- mice, as bile acid treatment significantly rescued P450 enzyme activity in Npc1-/- mice and has the potential to be an adjunctive therapy for NPC disease patients. The dysfunction in the cytochrome P450 system were recapitulated in the NPC1 feline model. Additionally, we present the first evidence that there are alterations in the P450 system in NPC1 patients. PMID:27019000

  14. Expression Profile of Genes Related to Drug Metabolism in Human Brain Tumors

    PubMed Central

    Stavrinou, Pantelis; Mavrogiorgou, Maria-Christina; Polyzoidis, Konstantinos; Kreft-Kerekes, Vincenzo; Timmer, Marco; Marselos, Marios; Pappas, Periklis

    2015-01-01

    Background Endogenous and exogenous compounds as well as carcinogens are metabolized and detoxified by phase I and II enzymes, the activity of which could be crucial to the inactivation and hence susceptibility to carcinogenic factors. The expression of these enzymes in human brain tumor tissue has not been investigated sufficiently. We studied the association between tumor pathology and the expression profile of seven phase I and II drug metabolizing genes (CYP1A1, CYP1B1, ALDH3A1, AOX1, GSTP1, GSTT1 and GSTM3) and some of their proteins. Methods Using qRT-PCR and western blotting analysis the gene and protein expression in a cohort of 77 tumors were investigated. The major tumor subtypes were meningioma, astrocytoma and brain metastases, -the later all adenocarcinomas from a lung primary. Results Meningeal tumors showed higher expression levels for AOX1, CYP1B1, GSTM3 and GSTP1. For AOX1, GSTM and GSTP1 this could be verified on a protein level as well. A negative correlation between the WHO degree of malignancy and the strength of expression was identified on both transcriptional and translational level for AOX1, GSTM3 and GSTP1, although the results could have been biased by the prevalence of meningiomas and glioblastomas in the inevitably bipolar distribution of the WHO grades. A correlation between the gene expression and the protein product was observed for AOX1, GSTP1 and GSTM3 in astrocytomas. Conclusions The various CNS tumors show different patterns of drug metabolizing gene expression. Our results suggest that the most important factor governing the expression of these enzymes is the histological subtype and to a far lesser extent the degree of malignancy itself. PMID:26580399

  15. Evaluation of enzyme immunoassay for anti-HBc IgM in the diagnosis of acute hepatitis B virus infection.

    PubMed

    Govindarajan, S; Ashcavai, M; Chau, K H; Nevalainen, D E; Peters, R L

    1984-09-01

    Corzyme-MTM (Abbott Laboratories, North Chicago, IL), a newly introduced kit for the measurement of serum IgM antihepatitis B core antigen by enzyme immunoassay, was evaluated for the diagnosis of acute B-viral hepatitis (AVH-B). The study included 175 acute viral hepatitis patients with transient hepatitis B surface antigen (HBsAg). Sera from 160 were tested on multiple occasions until their HBsAg cleared. IgM anti-HBc was found in 171 of 175 patients (98.4%) during the acute phase. The serum samples from 42 patients with liver biopsy-proven chronic active hepatitis, type B (CAH-B), and 18 patients with persistent hepatitis, type B (PH-B), were analyzed for the presence of IgM anti-HBc, using the same technic. None of the sera from 42 patients with CAH-B and only 2 of the 18 patients with PHB had IgM anti-HBc. Thus, the measuring IgM anti-HBc using Corzyme-M kit is helpful in the diagnosis of AVH-B and in the discrimination of acute from chronic HBV infections. PMID:6380271

  16. Liver Enzymes Are Associated With Hepatic Insulin Resistance, Insulin Secretion, and Glucagon Concentration in Healthy Men and Women

    PubMed Central

    Bonnet, Fabrice; Ducluzeau, Pierre-Henri; Gastaldelli, Amalia; Laville, Martine; Anderwald, Christian H.; Konrad, Thomas; Mari, Andrea; Balkau, Beverley

    2011-01-01

    OBJECTIVE The pathophysiological mechanisms to explain the association between risk of type 2 diabetes and elevated concentrations of γ-glutamyltransferase (GGT) and alanineaminotransferase (ALT) remain poorly characterized. We explored the association of liver enzymes with peripheral and hepatic insulin resistance, insulin secretion, insulin clearance, and glucagon concentration. RESEARCH DESIGN AND METHODS We studied 1,309 nondiabetic individuals from the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) study; all had a euglycemic-hyperinsulinemic clamp and an oral glucose tolerance test (OGTT) with assessment of insulin secretion and hepatic insulin extraction. The hepatic insulin resistance index was calculated in 393 individuals. RESULTS In both men and women, plasma concentrations of GGT and ALT were inversely related with insulin sensitivity (M/I) (all P < 0.01). Likewise, the hepatic insulin resistance index was positively correlated with both GGT (r = 0.37, P < 0.0001, men; r = 0.36, P < 0.0001, women) and ALT (r = 0.25, P = 0.0005, men; r = 0.18, P = 0.01, women). These associations persisted in multivariable models. Increased GGT and ALT were significantly associated with higher insulin secretion rates and with both reduced endogenous clearance of insulin and hepatic insulin extraction during the OGTT (P = 0.0005 in men; P = 0.003 in women). Plasma fasting glucagon levels increased over ALT quartiles (men, quartile 4 vs. quartile 1 11.2 ± 5.1 vs. 9.3 ± 3.8 pmol/L, respectively, P = 0.0002; women, 9.0 ± 4.3 vs. 7.6 ± 3.1, P = 0.001). CONCLUSIONS In healthy individuals, increased GGT and ALT were biomarkers of both systemic and hepatic insulin resistance with concomitant increased insulin secretion and decreased hepatic insulin clearance. The novel finding of a positive correlation between ALT and fasting glucagon level concentrations warrants confirmation in type 2 diabetes. PMID:21521874

  17. Effects of Radiation and Dietary Iron on Expression of Genes and Proteins Involved in Drug Metabolism

    NASA Technical Reports Server (NTRS)

    Faust, K. M.; Wotring, V. E.

    2014-01-01

    Liver function, especially the rate of metabolic enzyme activities, determines the concentration of circulating drugs and the duration of their efficacy. Most pharmaceuticals are metabolized by the liver, and clinically-used medication doses are given with normal liver function in mind. A drug overdose can result in the case of a liver that is damaged and removing pharmaceuticals from the circulation at a rate slower than normal. Alternatively, if liver function is elevated and removing drugs from the system more quickly than usual, it would be as if too little drug had been given for effective treatment. Because of the importance of the liver in drug metabolism, we want to understand any effects of spaceflight on the enzymes of the liver. Dietary factors and exposure to radiation are aspects of spaceflight that are potential oxidative stressors and both can be modeled in ground experiments. In this experiment, we examined the effects of high dietary iron and low dose gamma radiation (individually and combined) on the gene expression of enzymes involved in drug metabolism, redox homeostasis, and DNA repair. METHODS All procedures were approved by the JSC Animal Care and Use Committee. Male Sprague-Dawley rats were divided into 4 groups (n=8); control, high Fe diet (650 mg iron/kg), radiation (fractionated 3 Gy exposure from a Cs- 137 source) and combined high Fe diet + radiation exposure. Animals were euthanized 24h after the last treatment of radiation; livers were removed immediately and flash -frozen in liquid nitrogen. Expression of genes thought to be involved in redox homeostasis, drug metabolism and DNA damage repair was measured by RT-qPCR. Where possible, protein expression of the same genes was measured by western blotting. All data are expressed as % change in expression normalized to reference gene expression; comparisons were then made of each treatment group to the sham exposed/ normal diet control group. Data was considered significant at p< 0

  18. Functional Integrity of the Chimeric (Humanized) Mouse Liver: Enzyme Zonation, Physiologic Spaces, and Hepatic Enzymes and Transporters.

    PubMed

    Chow, Edwin C Y; Wang, Jason Z Ya; Quach, Holly P; Tang, Hui; Evans, David C; Li, Albert P; Silva, Jose; Pang, K Sandy

    2016-09-01

    Chimeric mouse liver models are useful in vivo tools for human drug metabolism studies; however, liver integrity and the microcirculation remain largely uninvestigated. Hence, we conducted liver perfusion studies to examine these attributes in FRGN [Fah(-/-), Rag2(-/-), and Il2rg(-/-), NOD strain] livers (control) and chimeric livers repopulated with mouse (mFRGN) or human (hFRGN) hepatocytes. In single-pass perfusion studies (2.5 ml/min), outflow dilution profiles of noneliminated reference indicators ((51)Cr-RBC, (125)I-albumin, (14)C-sucrose, and (3)H-water) revealed preservation of flow-limited distribution and reduced water and albumin spaces in hFRGN livers compared with FRGN livers, a view supported microscopically by tightly packed sinusoids. With prograde and retrograde perfusion of harmol (50 µM) in FRGN livers, an anterior sulfation (Sult1a1) over the posterior distribution of glucuronidation (Ugt1a1) activity was preserved, evidenced by the 42% lower sulfation-to-glucuronidation ratio (HS/HG) and 14% higher harmol extraction ratio (E) upon switching from prograde to retrograde flow. By contrast, zonation was lost in mFRGN and hFRGN livers, with HS/HG and E for both flows remaining unchanged. Remnant mouse genes persisted in hFRGN livers (10%-300% those of FRGN). When hFRGN livers were compared with human liver tissue, higher UGT1A1 and MRP2, lower MRP3, and unchanged SULT1A1 and MRP4 mRNA expression were observed. Total Sult1a1/SULT1A1 protein expression in hFRGN livers was higher than that of FRGN livers, consistent with higher harmol sulfate formation. The composite data on humanized livers suggest a loss of zonation, lack of complete liver humanization, and persistence of murine hepatocyte activities leading to higher sulfation. PMID:27342868

  19. Hepatic steroid inactivating enzymes, hepatic portal blood flow, and corpus luteum blood perfusion in lactating dairy cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In ruminants, a decrease in pregnancy rates may be due to decreased concentrations of progesterone (P4). It is important to note that both production from the corpus luteum and/or hepatic steroid inactivation impacts peripheral concentrations of P4. Cattle with an elevated dry matter intake have inc...

  20. Oxidative Modification of Rat Sulfotransferase 1A1 Activity in Hepatic Tissue Slices Correlates with Effects on the Purified Enzyme

    PubMed Central

    Dammanahalli, Jagadeesha K.

    2012-01-01

    Mammalian cytosolic sulfotransferases (SULTs) catalyze the sulfation of xenobiotics as well as numerous endogenous molecules. The major aryl (phenol) SULT in rat liver, rSULT1A1, has been used extensively as a model enzyme for understanding the catalytic function of SULTs. Previous studies showed that purified rSULT1A1 displays significant catalytic changes in the presence of GSSG and other oxidants. In the present study, the effects of diamide [1,1′-azobis(N,N-dimethylformamide)] and tert-butyl hydroperoxide (TBHP) on the activity of rSULT1A1 in rat hepatic slices were compared with the effects of these oxidants on a homogeneous preparation of the enzyme. Precision-cut hepatic slices were incubated with 10 μM 7-hydroxycoumarin (7-HC) in the presence of varied concentrations of either diamide or TBHP. Analysis of the 7-hydroxycoumarin sulfate released into the incubation medium indicated that both oxidants significantly increased the sulfation of 7-HC, and this occurred at optimal concentrations of 5 and 10 μM, respectively. Cellular GSH and GSSG levels in the hepatic slices were not significantly altered from control values at these concentrations of diamide and TBHP. Exposure of homogeneous rSULT1A1 to diamide or TBHP also increased the rate of sulfation of 7-HC, although the optimal concentrations of diamide and TBHP were lower (50- and 100-fold, respectively) than those required for effects with the hepatic slices. These results indicate that both diamide and TBHP may modify the rSULT1A1 in intact cells in a manner similar to that observed with the homogeneous purified enzyme. PMID:22041107

  1. Effects of tin-protoporphyrin administration on hepatic xenobiotic metabolizing enzymes in the juvenile rat

    SciTech Connect

    Stout, D.L.; Becker, F.F.

    1988-01-01

    The heme analogue tin-protoporphyrin IX (SnP) is a potent inhibitor of microsomal heme oxygenase. Administration of SnP to neonatal rats can prevent hyperbilirubinemia by blocking the postnatal increase of heme oxygenase activity. Apparently innocuous at therapeutic doses, it is of potential clinical value for chemoprevention of neonatal jaundice. We found that when 50-g male Sprague-Dawley rats were treated daily with 50 mumol of SnP/kg sc for 6 days, hepatic microsomal cytochromes b5 and P-450 were significantly diminished. Cytochrome P-450 reductase, two P-450-dependent monooxygenases, aminopyrine demethylase and benzo(a)pyrene hydroxylase, and catalase, a peroxisomal hemoprotein, were also significantly diminished. These results suggested that SnP might significantly affect the metabolism of other xenobiotics. This possibility was confirmed by the finding that hexobarbital-induced sleep lasted 4 times longer in SnP-treated rats than in controls. Inhibition of protein synthesis by SnP was ruled out as the cause of hemoprotein loss when administration of (/sup 3/H)leucine to SnP-treated and control rats demonstrated that proteins of the microsomal, cytosolic, and plasma membrane fractions of the livers from both groups incorporated similar levels of leucine. When /sup 55/FeCl/sub 3/ and (2-/sup 14/C)glycine were administered to measure heme synthesis, heme extract from the livers of SnP-treated rats contained 4 times more label from iron and glycine than did heme from control livers. Despite the apparent increased rate of heme synthesis in SnP-treated rats, each of the three cell fractions demonstrated a significant loss of heme but contained sizable amounts of SnP. These findings suggest that SnP causes a decrease of functional hemoprotein and partial loss of enzymic activity by displacing intracellular heme.

  2. Human variation and CYP enzyme contribution in benfuracarb metabolism in human in vitro hepatic models.

    PubMed

    Abass, Khaled; Reponen, Petri; Mattila, Sampo; Rautio, Arja; Pelkonen, Olavi

    2014-01-13

    Human responses to the toxicological effects of chemicals are often complicated by a substantial interindividual variability in toxicokinetics, of which metabolism is often the most important factor. Therefore, we investigated human variation and the contributions of human-CYP isoforms to in vitro metabolism of benfuracarb. The primary metabolic pathways were the initial sulfur oxidation to benfuracarb-sulfoxide and the nitrogen-sulfur bond cleavage to carbofuran (activation). The Km, Vmax, and CL(int) values of carbofuran production in ten individual hepatic samples varied 7.3-, 3.4-, and 5.4-fold, respectively. CYP2C9 and CYP2C19 catalyzed benfuracarb sulphur oxidation. Carbofuran formation, representing from 79% to 98% of the total metabolism, was catalyzed predominantly by CYP3A4. The calculated relative contribution of CYP3A4 to carbofuran formation was 93%, while it was 4.4% for CYP2C9. The major contribution of CYP3A4 in benfuracarb metabolism was further substantiated by showing a strong correlation with CYP3A4-selective markers midazolam-1'-hydroxylation and omeprazole-sulfoxidation (r=0.885 and 0.772, respectively). Carbofuran formation was highly inhibited by the CYP3A inhibitor ketoconazole. Moreover, CYP3A4 marker activities were relatively inhibited by benfuracarb. These results confirm that human CYP3A4 is the major enzyme involved in the in vitro activation of benfuracarb and that CYP3A4-catalyzed metabolism is the primary source of interindividual differences. PMID:24016712

  3. Hepatitis

    MedlinePlus

    ... be serious. Some can lead to scarring, called cirrhosis, or to liver cancer. Sometimes hepatitis goes away by itself. If it does not, it can be treated with drugs. Sometimes hepatitis lasts a lifetime. Vaccines can help prevent some viral forms.

  4. A Human Hepatocyte-Bearing Mouse: An Animal Model to Predict Drug Metabolism and Effectiveness in Humans

    PubMed Central

    Yoshizato, Katsutoshi; Tateno, Chise

    2009-01-01

    Preclinical studies to predict the efficacy and safety of drugs have conventionally been conducted almost exclusively in mice and rats as rodents, despite the differences in drug metabolism between humans and rodents. Furthermore, human (h) viruses such as hepatitis viruses do not infect the rodent liver. A mouse bearing a liver in which the hepatocytes have been largely repopulated with h-hepatocytes would overcome some of these disadvantages. We have established a practical, efficient, and large-scale production system for such mice. Accumulated evidence has demonstrated that these hepatocyte-humanized mice are a useful and reliable animal model, exhibiting h-type responses in a series of in vivo drug processing (adsorption, distribution, metabolism, excretion) experiments and in the infection and propagation of hepatic viruses. In this review, we present the current status of studies on chimeric mice and describe their usefulness in the study of peroxisome proliferator-activated receptors. PMID:19884982

  5. Enzyme

    MedlinePlus

    Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

  6. Effect of the combined probiotics with aflatoxin B₁-degrading enzyme on aflatoxin detoxification, broiler production performance and hepatic enzyme gene expression.

    PubMed

    Zuo, Rui-yu; Chang, Juan; Yin, Qing-qiang; Wang, Ping; Yang, Yu-rong; Wang, Xiao; Wang, Guo-qiang; Zheng, Qiu-hong

    2013-09-01

    In order to degrade aflatoxin B₁ (AFB₁), AFB₁-degrading microbes (probiotics) such as Lactobacillus casei, Bacillus subtilis and Pichia anomala, and the AFB₁-degrading enzyme from Aspergillus oryzae were selected and combined to make feed additive. Seventy-five 43-day-old male Arbor Acres broilers were randomly divided into 5 groups, 15 broilers for each group. The broilers were given with 5 kinds of diets such as the basal diet, 400 μg/kg AFB₁ supplement without feed additive, and 200, 400, 800 μg/kg AFB₁ supplement with 0.15% feed additive. The feeding experimental period was 30 d, which was used to determine production performance of broilers. In addition, serum, liver and chest muscle were selected for measuring AFB₁ residues, gene expressions, microscopic and antioxidant analyses. The results showed that adding 0.15% feed additive in broiler diets could significantly relieve the negative effect of AFB₁ on chicken's production performance and nutrient metabolic rates (P<0.05). It could also improve AFB₁ metabolism, hepatic cell structure, antioxidant activity, and many hepatic enzyme gene expressions involved in oxidoreductase, apoptosis, cell growth, immune system and metabolic process (P<0.05). It could be concluded that the feed additive was able to degrade AFB₁ and improve animal production. PMID:23831311

  7. Predictors of Hepatitis B Cure Using Gene Therapy to Deliver DNA Cleavage Enzymes: A Mathematical Modeling Approach

    PubMed Central

    Schiffer, Joshua T.; Swan, Dave A.; Stone, Daniel; Jerome, Keith R.

    2013-01-01

    Most chronic viral infections are managed with small molecule therapies that inhibit replication but are not curative because non-replicating viral forms can persist despite decades of suppressive treatment. There are therefore numerous strategies in development to eradicate all non-replicating viruses from the body. We are currently engineering DNA cleavage enzymes that specifically target hepatitis B virus covalently closed circular DNA (HBV cccDNA), the episomal form of the virus that persists despite potent antiviral therapies. DNA cleavage enzymes, including homing endonucleases or meganucleases, zinc-finger nucleases (ZFNs), TAL effector nucleases (TALENs), and CRISPR-associated system 9 (Cas9) proteins, can disrupt specific regions of viral DNA. Because DNA repair is error prone, the virus can be neutralized after repeated cleavage events when a target sequence becomes mutated. DNA cleavage enzymes will be delivered as genes within viral vectors that enter hepatocytes. Here we develop mathematical models that describe the delivery and intracellular activity of DNA cleavage enzymes. Model simulations predict that high vector to target cell ratio, limited removal of delivery vectors by humoral immunity, and avid binding between enzyme and its DNA target will promote the highest level of cccDNA disruption. Development of de novo resistance to cleavage enzymes may occur if DNA cleavage and error prone repair does not render the viral episome replication incompetent: our model predicts that concurrent delivery of multiple enzymes which target different vital cccDNA regions, or sequential delivery of different enzymes, are both potentially useful strategies for avoiding multi-enzyme resistance. The underlying dynamics of cccDNA persistence are unlikely to impact the probability of cure provided that antiviral therapy is given concurrently during eradication trials. We conclude by describing experiments that can be used to validate the model, which will in turn

  8. Effects of PCBs on plasma enzymes, testosterone level, and hepatic xenobiotic metabolism in the grey partridge, perdix perdlx

    SciTech Connect

    Abiola, F. ); Lorgue, G.; Riviere, J.L. ); Benoit, E. ); Soyez, D. )

    1989-09-01

    The hepatic cytochrome P-450-dependent monooxygenase (MO) system functions in oxidative biotransformation of a wide variety of both endogenous and exogenous (xenobiotic) compounds in many animal species. However, most of the previous studies were carried out with a narrow range of species and investigations on wild species are lacking. In this report, the authors describe the effects of a commercial mixture of PCBs (DP5) on the hepatic MO activities of the grey partridge (Perdix perdix). To more thoroughly investigate the inducing effects of DP5, they used two series of homologous substrates, alkylresorufins and alkoxycoumarins, and an endogenous compound, testosterone, which were shown in mammals to differentiate between different forms of cytochrome P-450. Furthermore, to more carefully assess the effects of DP5, they also measured the activity of two plasma marker enzymes, alanine transpeptidase (ALAT) and gamma-glutamyl transferase (gamma-GT), and the plasmatic concentration of testosterone.

  9. Angiotensin-converting enzyme 2/angiotensin-(1–7)/Mas axis activates Akt signaling to ameliorate hepatic steatosis

    PubMed Central

    Cao, Xi; Yang, Fangyuan; Shi, Tingting; Yuan, Mingxia; Xin, Zhong; Xie, Rongrong; Li, Sen; Li, Hongbing; Yang, Jin-Kui

    2016-01-01

    The classical axis of renin-angiotensin system (RAS), angiotensin (Ang)-converting enzyme (ACE)/Ang II/AT1, contributes to the development of non-alcoholic fatty liver disease (NAFLD). However, the role of bypass axis of RAS (Angiotensin-converting enzyme 2 (ACE2)/Ang-(1–7)/Mas) in hepatic steatosis is still unclear. Here we showed that deletion of ACE2 aggravates liver steatosis, which is correlated with the increased expression of hepatic lipogenic genes and the decreased expression of fatty acid oxidation-related genes in the liver of ACE2 knockout (ACE2−/y) mice. Meanwhile, oxidative stress and inflammation were also aggravated in ACE2−/y mice. On the contrary, overexpression of ACE2 improved fatty liver in db/db mice, and the mRNA levels of fatty acid oxidation-related genes were up-regulated. In vitro, Ang-(1–7)/ACE2 ameliorated hepatic steatosis, oxidative stress and inflammation in free fatty acid (FFA)-induced HepG2 cells, and what’s more, Akt inhibitors reduced ACE2-mediated lipid metabolism. Furthermore, ACE2-mediated Akt activation could be attenuated by blockade of ATP/P2 receptor/Calmodulin (CaM) pathway. These results indicated that Ang-(1–7)/ACE2/Mas axis may reduce liver lipid accumulation partly by regulating lipid-metabolizing genes through ATP/P2 receptor/CaM signaling pathway. Our findings support the potential role of ACE2/Ang-(1–7)/Mas axis in prevention and treatment of hepatic lipid metabolism. PMID:26883384

  10. Angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas axis activates Akt signaling to ameliorate hepatic steatosis.

    PubMed

    Cao, Xi; Yang, Fangyuan; Shi, Tingting; Yuan, Mingxia; Xin, Zhong; Xie, Rongrong; Li, Sen; Li, Hongbing; Yang, Jin-Kui

    2016-01-01

    The classical axis of renin-angiotensin system (RAS), angiotensin (Ang)-converting enzyme (ACE)/Ang II/AT1, contributes to the development of non-alcoholic fatty liver disease (NAFLD). However, the role of bypass axis of RAS (Angiotensin-converting enzyme 2 (ACE2)/Ang-(1-7)/Mas) in hepatic steatosis is still unclear. Here we showed that deletion of ACE2 aggravates liver steatosis, which is correlated with the increased expression of hepatic lipogenic genes and the decreased expression of fatty acid oxidation-related genes in the liver of ACE2 knockout (ACE2(-/y)) mice. Meanwhile, oxidative stress and inflammation were also aggravated in ACE2(-/y) mice. On the contrary, overexpression of ACE2 improved fatty liver in db/db mice, and the mRNA levels of fatty acid oxidation-related genes were up-regulated. In vitro, Ang-(1-7)/ACE2 ameliorated hepatic steatosis, oxidative stress and inflammation in free fatty acid (FFA)-induced HepG2 cells, and what's more, Akt inhibitors reduced ACE2-mediated lipid metabolism. Furthermore, ACE2-mediated Akt activation could be attenuated by blockade of ATP/P2 receptor/Calmodulin (CaM) pathway. These results indicated that Ang-(1-7)/ACE2/Mas axis may reduce liver lipid accumulation partly by regulating lipid-metabolizing genes through ATP/P2 receptor/CaM signaling pathway. Our findings support the potential role of ACE2/Ang-(1-7)/Mas axis in prevention and treatment of hepatic lipid metabolism. PMID:26883384

  11. Role of Cytochrome P450 2C8 in Drug Metabolism and Interactions.

    PubMed

    Backman, Janne T; Filppula, Anne M; Niemi, Mikko; Neuvonen, Pertti J

    2016-01-01

    During the last 10-15 years, cytochrome P450 (CYP) 2C8 has emerged as an important drug-metabolizing enzyme. CYP2C8 is highly expressed in human liver and is known to metabolize more than 100 drugs. CYP2C8 substrate drugs include amodiaquine, cerivastatin, dasabuvir, enzalutamide, imatinib, loperamide, montelukast, paclitaxel, pioglitazone, repaglinide, and rosiglitazone, and the number is increasing. Similarly, many drugs have been identified as CYP2C8 inhibitors or inducers. In vivo, already a small dose of gemfibrozil, i.e., 10% of its therapeutic dose, is a strong, irreversible inhibitor of CYP2C8. Interestingly, recent findings indicate that the acyl-β-glucuronides of gemfibrozil and clopidogrel cause metabolism-dependent inactivation of CYP2C8, leading to a strong potential for drug interactions. Also several other glucuronide metabolites interact with CYP2C8 as substrates or inhibitors, suggesting that an interplay between CYP2C8 and glucuronides is common. Lack of fully selective and safe probe substrates, inhibitors, and inducers challenges execution and interpretation of drug-drug interaction studies in humans. Apart from drug-drug interactions, some CYP2C8 genetic variants are associated with altered CYP2C8 activity and exhibit significant interethnic frequency differences. Herein, we review the current knowledge on substrates, inhibitors, inducers, and pharmacogenetics of CYP2C8, as well as its role in clinically relevant drug interactions. In addition, implications for selection of CYP2C8 marker and perpetrator drugs to investigate CYP2C8-mediated drug metabolism and interactions in preclinical and clinical studies are discussed. PMID:26721703

  12. Drug metabolism and pharmacokinetic diversity of ranunculaceae medicinal compounds.

    PubMed

    Hao, Da-Cheng; Ge, Guang-Bo; Xiao, Pei-Gen; Wang, Ping; Yang, Ling

    2015-01-01

    The wide-reaching distributed angiosperm family Ranunculaceae has approximately 2200 species in around 60 genera. Chemical components of this family include several representative groups: benzylisoquinoline alkaloid (BIA), ranunculin, triterpenoid saponin and diterpene alkaloid, etc. Their extensive clinical utility has been validated by traditional uses of thousands of years and current evidence-based medicine studies. Drug metabolism and pharmacokinetic (DMPK) studies of plant-based natural products are an indispensable part of comprehensive medicinal plant exploration, which could facilitate conservation and sustainable utilization of Ranunculaceae pharmaceutical resources, as well as new chemical entity development with improved DMPK parameters. However, DMPK characteristics of Ranunculaceaederived medicinal compounds have not been summarized. Black cohosh (Cimicifuga) and goldenseal (Hydrastis) raise concerns of herbdrug interaction. DMPK studies of other Ranunculaceae genera, e.g., Nigella, Delphinium, Aconitum, Trollius, and Coptis, are also rapidly increasing and becoming more and more clinically relevant. In this contribution, we highlight the up-to-date awareness, as well as the challenges around the DMPK-related issues in optimization of drug development and clinical practice of Ranunculaceae compounds. Herb-herb interaction of Ranunculaceae herb-containing traditional Chinese medicine (TCM) formula could significantly influence the in vivo pharmacokinetic behavior of compounds thereof, which may partially explain the complicated therapeutic mechanism of TCM formula. Although progress has been made on revealing the absorption, distribution, metabolism, excretion and toxicity (ADME/T) of Ranunculaceae compounds, there is a lack of DMPK studies of traditional medicinal genera Aquilegia, Thalictrum and Clematis. Fluorescent probe compounds could be promising substrate, inhibitor and/or inducer in future DMPK studies of Ranunculaceae compounds. A better

  13. Microprinting of liver micro-organ for drug metabolism study.

    PubMed

    Chang, Robert C; Emami, Kamal; Jeevarajan, Antony; Wu, Honglu; Sun, Wei

    2011-01-01

    their collective drug metabolic function and suitability as a drug metabolism model. PMID:20967633

  14. Shedding light on minipig drug metabolism - elevated amide hydrolysis in vitro.

    PubMed

    Jones, Russell; Marschmann, Michaela; Keller, Michael; Qiu, Na Hong; Fowler, Stephen; Singer, Thomas; Schuler, Franz; Funk, Christoph; Schadt, Simone

    2016-06-01

    1. In recent years, the minipig is increasingly used as a test species in non-clinical assessment of drug candidates. While there is good scientific evidence available concerning cytochrome P450-mediated metabolism in minipig, the knowledge of other metabolic pathways is more limited. 2. The aim of this study was to provide an understanding of when, why, and how drug metabolism in minipig differs from other species commonly used in non-clinical studies. In-house cross-species metabolite profile comparisons in hepatocytes and microsomes of 38 Roche development compounds were retrospectively analyzed to compare the metabolism among minipig, human, rat, dog, monkey, rabbit and mouse. 3. A significant contributor to the elevated metabolism observed for certain compounds in minipig was identified as amide hydrolysis. The hepatic amide hydrolysis activity in minipig was further investigated in subcellular liver fractions and a structure-activity relationship was established. When structural motifs according to the established SAR are excluded, coverage of major human metabolic pathways was shown to be higher in minipig than in dog, and only slightly lower than in cynomolgus monkey. 4. A strategy is presented for early identification of drug compounds which might not be suited to further investigation in minipig due to excessive hydrolytic metabolism. PMID:26405846

  15. DEHP reduces thyroid hormones via interacting with hormone synthesis-related proteins, deiodinases, transthyretin, receptors, and hepatic enzymes in rats.

    PubMed

    Liu, Changjiang; Zhao, Letian; Wei, Li; Li, Lianbing

    2015-08-01

    Di-(2-ethylhexyl) phthalate (DEHP) is used extensively in many personal care and consumer products, resulting in widespread nonoccupational human exposure through multiple routes and media. Limited studies suggest that exposure to DEHP may be associated with altered thyroid function, but detailed mechanisms are unclear. In order to elucidate potential mechanisms by which DEHP disturbs thyroid hormone homeostasis, Sprague-Dawley (SD) rats were dosed with DEHP by gavage at 0, 250, 500, and 750 mg/kg/day for 30 days and sacrificed within 24 h after the last dose. Gene expressions of thyroid hormone receptors, deiodinases, transthyretin, and hepatic enzymes were measured by RT-PCR; protein levels of transthyretin were also analyzed by Western blot. Results showed that DEHP caused histological changes in the thyroid and follicular epithelial cell hypertrophy and hyperplasia were observed. DEHP significantly reduced thyroid hormones (T3, T4) and thyrotropin releasing hormone (TRH) levels, whereas thyroid stimulating hormone (TSH) was not affected. After exposure to DEHP, biosynthesis of thyroid hormones was suppressed, and sodium iodide symporter (NIS) and thyroid peroxidase (TPO) levels were significantly reduced. Additionally, levels of deiodinases and transthyretin were also affected. TSH receptor (TSHr) level was downregulated, while TRH receptor (TRHr) level was upregulated. Metabolism of thyroid hormones was accelerated due to elevated gene expression of hepatic enzymes (UDPGTs and CYP2B1) by DEHP. Taken together, observed findings indicate that DEHP could reduce thyroid hormones through influencing biosynthesis, biotransformation, biotransport, receptor levels, and metabolism of thyroid hormones. PMID:25913319

  16. PCB153 and p,p'-DDE disorder thyroid hormones via thyroglobulin, deiodinase 2, transthyretin, hepatic enzymes and receptors.

    PubMed

    Liu, Changjiang; Ha, Mei; Li, Lianbing; Yang, Kedi

    2014-10-01

    Polychlorinated biphenyls (PCBs) and DDT are widespread environmental persistent organic pollutants that have various adverse effects on reproduction, development and endocrine function. In order to elucidate effects of PCBs and DDT on thyroid hormone homeostasis, Sprague-Dawley rats were dosed with PCB153 and p,p'-DDE intraperitoneally (ip) for five consecutive days and sacrificed within 24 h after the last dose. Results indicated that after combined exposure to PCB153 and p,p'-DDE, total thyroxine , free thyroxine, total triiodothyronine, and thyroid-stimulating hormone in serum were decreased, whereas free triiodothyronine and thyrotropin-releasing hormone were not affected. Thyroglobulin and transthyretin levels in serum were significantly reduced. mRNA expression of deiodinases 2 (D2) was also suppressed, while D1 and D3 levels were not significantly influenced after combined exposure. PCB153 and p,p'-DDE induced hepatic enzymes, UDPGTs, CYP1A1, CYP2B1, and CYP3A1 mRNA expressions being significantly elevated. Moreover, TRα1, TRβ1, and TRHr expressions in the hypothalamus displayed increasing trends after combined exposure to PCB153 and p,p'-DDE. Taken together, observed results indicate that PCB153 and p,p'-DDE could disorder thyroid hormone homeostasis via thyroglobulin, deiodinase 2, transthyretin, hepatic enzymes, and hormone receptors. PMID:24878560

  17. Effect of Nigella sativa fixed and essential oils on antioxidant status, hepatic enzymes, and immunity in streptozotocin induced diabetes mellitus

    PubMed Central

    2014-01-01

    Background Nigella sativa fixed (NSFO) and essential (NSEO) oils have been used to treat diabetes mellitus and its complications. Present study was undertaken to explore and validate these folkloric uses. Methods Sprague dawley rats having streptozotocin (STZ) induced diabetes mellitus were used to assess the role of NSFO and NSEO in the management of diabetes complications. Parameters investigated were antioxidant potential, oxidative stress, and the immunity by in vivo experiments. Results The results indicated that STZ decreased the glutathione contents (25.72%), while NSFO and NSEO increased the trait significantly (P < 0.05). Experimental diets increased the tocopherol contents (P < 0.01) and enhanced the expression of hepatic enzymes (P < 0.01). Correlation matrix further indicated that antioxidant potential is positively associated (P < 0.05) responsible for the modulation of hepatic enzymes and the decrease of the nitric oxide production thus controlling the diabetes complications. Conclusions Overall, results of present study supported the traditional use of N. sativa and its derived products as a treatment for hyperglycemia and allied abnormalities. Moreover, N. sativa fixed and essential oils significantly ameliorate free radicals and improve antioxidant capacity thus reducing the risk of diabetic complications. PMID:24939518

  18. Activity of hepatic but not skeletal muscle carnitine palmitoyltransferase enzyme is depressed by intravenous glucose infusions in lactating dairy cows.

    PubMed

    Al-Trad, B; Wittek, T; Gäbel, G; Fürll, M; Reisberg, K; Aschenbach, J R

    2010-12-01

    A positive energy balance in dairy cows pre-partum may decrease hepatic carnitine palmitoyltransferase (CPT) enzyme activity, which might contribute to disturbances of lipid metabolism post-partum. The purpose of this study was to investigate whether skeletal muscle CPT activity can also be downregulated during positive energy balance. Mid-lactating dairy cows were maintained on intravenous infusion of either saline (control) or glucose solutions that increased linearly over 24 days, remained at the 24-day level until day 28 and were suspended thereafter. Liver and skeletal muscle biopsies, as well as four diurnal blood samples, were taken on days 0, 8, 16, 24, and 32, representing infusion levels equivalent to 0%, 10%, 20%, 30% and 0% of the net energy for lactation (NE(L)) requirement respectively. Glucose infusion increased serum insulin concentrations on day 16 and 24 while plasma glucose levels were increased at only a single time point on day 24. Serum beta-hydroxybutyric acid concentrations decreased between day 8 and 24; whereas changes in non-esterified fatty acids were mostly insignificant. Total lipid contents of liver and skeletal muscle were not affected by treatment. Hepatic CPT activity decreased with glucose infusion (by 35% on day 24) and remained decreased on day 32. Hepatic expression levels of CPT-1A and CPT-2 mRNA were not significantly altered but tended to reflect the changes in enzyme activity. In contrast to the liver, no effect of glucose infusion was observed on skeletal muscle CPT activity. We conclude that suppression of CPT activity by positive energy balance appears to be specific for the liver in mid-lactating dairy cows. PMID:20546068

  19. Stereochemical aspects of vinylcyclohexene bioactivation in rodent hepatic microsomes and purified human cytochrome P450 enzyme systems.

    PubMed

    Fontaine, S M; Mash, E A; Hoyer, P B; Sipes, I G

    2001-02-01

    The racemic mixture of 4-vinylcyclohexene (VCH) forms ovotoxic epoxides [VCH-1,2-epoxide, VCH-7,8-epoxide, and vinylcyclohexene diepoxide (VCD)] by cytochrome P450 (CYP) in B6C3F(1) female mice. These epoxides deplete primordial and primary follicles. The current studies compared in vitro epoxidation of (R)-VCH with that of (S)-VCH in hepatic microsomes prepared from adult female B6C3F(1) mice and Fischer 344 rats. Bioactivation of VCH in the rat was significantly less compared with that in the mouse. (R)-VCH formed significantly more VCH-1,2-epoxide as compared with (S)-VCH in both species, and less VCH-7,8-epoxide in the mouse. Neither of the enantiomers formed detectable amounts of VCD in the mouse or rat. Hepatic microsomes prepared from mice and rats pretreated with CYP-inducing agents (phenobarbital and acetone) were also incubated with (R)-VCH or (S)-VCH. Although monoepoxide formation was not increased enantioselectively in the mouse, VCD was formed preferentially from (R)-VCH as compared with (S)-VCH. Pretreatment with VCH resulted in nonstereoselective increases in both monoepoxide and diepoxide formation. In the rat, these pretreatments resulted in nonstereoselective increases in monoepoxide formation, but VCD formation was not detectable. Incubations with human CYP2E1 enzyme revealed that (R)-VCH formed significantly more VCH-1,2-epoxide and less VCH-7,8-epoxide than (S)-VCH. Human CYP2A6 was limited in its ability to form epoxides from either enantiomer of VCH. Human CYP2B6 preferentially formed VCH-7,8-epoxide compared with VCH-1,2-epoxide, and to a greater extent from (R)-VCH than from (S)-VCH. These results demonstrate regioselectivity and enantioselectivity in the bioactivation of VCH in rodent hepatic microsomes as well as in expressed human CYP enzymes. PMID:11159809

  20. Using chimeric mice with humanized livers to predict human drug metabolism and a drug-drug interaction.

    PubMed

    Nishimura, Toshihiko; Nishimura, Toshiko; Hu, Yajing; Wu, Manhong; Pham, Edward; Suemizu, Hiroshi; Elazar, Menashe; Liu, Michael; Idilman, Ramazan; Yurdaydin, Cihan; Angus, Peter; Stedman, Catherine; Murphy, Brian; Glenn, Jeffrey; Nakamura, Masato; Nomura, Tatsuji; Chen, Yuan; Zheng, Ming; Fitch, William L; Peltz, Gary

    2013-02-01

    Interspecies differences in drug metabolism have made it difficult to use preclinical animal testing data to predict the drug metabolites or potential drug-drug interactions (DDIs) that will occur in humans. Although chimeric mice with humanized livers can produce known human metabolites for test substrates, we do not know whether chimeric mice can be used to prospectively predict human drug metabolism or a possible DDI. Therefore, we investigated whether they could provide a more predictive assessment for clemizole, a drug in clinical development for the treatment of hepatitis C virus (HCV) infection. Our results demonstrate, for the first time, that analyses performed in chimeric mice can correctly identify the predominant human drug metabolite before human testing. The differences in the rodent and human pathways for clemizole metabolism were of importance, because the predominant human metabolite was found to have synergistic anti-HCV activity. Moreover, studies in chimeric mice also correctly predicted that a DDI would occur in humans when clemizole was coadministered with a CYP3A4 inhibitor. These results demonstrate that using chimeric mice can improve the quality of preclinical drug assessment. PMID:23143674

  1. Interactions of the hepatitis C virus protease inhibitor faldaprevir with cytochrome P450 enzymes: in vitro and in vivo correlation.

    PubMed

    Sabo, John P; Kort, Jens; Ballow, Charles; Kashuba, Angela D M; Haschke, Manuel; Battegay, Manuel; Girlich, Birgit; Ting, Naitee; Lang, Benjamin; Zhang, Wei; Cooper, Curtis; O'Brien, Drané; Seibert, Eleanore; Chan, Tom S; Tweedie, Donald; Li, Yongmei

    2015-04-01

    The potential inhibition of the major human cytochrome P450 (CYP) enzymes by faldaprevir was evaluated both in vitro and in clinical studies (healthy volunteers and hepatitis C virus [HCV] genotype 1-infected patients). In vitro studies indicated that faldaprevir inhibited CYP2B6, CYP2C9, and CYP3A, and was a weak-to-moderate inactivator of CYP3A4. Faldaprevir 240 mg twice daily in healthy volunteers demonstrated moderate inhibition of hepatic and intestinal CYP3A (oral midazolam: 2.96-fold increase in AUC(0-24 h)), weak inhibition of hepatic CYP3A (intravenous midazolam: 1.56-fold increase in AUC(0-24 h)), weak inhibition of CYP2C9 ([S]-warfarin: 1.29-fold increase in AUC(0-120 h)), and had no relevant effects on CYP1A2, CYP2B6, or CYP2D6. Faldaprevir 120 mg once daily in HCV-infected patients demonstrated weak inhibition of hepatic and intestinal CYP3A (oral midazolam: 1.52-fold increase in AUC(0-∞)), and had no relevant effects on CYP2C9 or CYP1A2. In vitro drug-drug interaction predictions based on inhibitor concentration ([I])/inhibition constant (Ki) ratios tended to overestimate clinical effects and a net-effect model provided a more accurate approach. These studies suggest that faldaprevir shows a dose-dependent inhibition of CYP3A and CYP2C9, and does not induce CYP isoforms. PMID:25449227

  2. Antihypertensive Drugs Metabolism: An Update to Pharmacokinetic Profiles and Computational Approaches

    PubMed Central

    Zisaki, Aikaterini; Miskovic, Ljubisa; Hatzimanikatis, Vassily

    2015-01-01

    Drug discovery and development is a high-risk enterprise that requires significant investments in capital, time and scientific expertise. The studies of xenobiotic metabolism remain as one of the main topics in the research and development of drugs, cosmetics and nutritional supplements. Antihypertensive drugs are used for the treatment of high blood pressure, which is one the most frequent symptoms of the patients that undergo cardiovascular diseases such as myocardial infraction and strokes. In current cardiovascular disease pharmacology, four drug clusters - Angiotensin Converting Enzyme Inhibitors, Beta-Blockers, Calcium Channel Blockers and Diuretics - cover the major therapeutic characteristics of the most antihypertensive drugs. The pharmacokinetic and specifically the metabolic profile of the antihypertensive agents are intensively studied because of the broad inter-individual variability on plasma concentrations and the diversity on the efficacy response especially due to the P450 dependent metabolic status they present. Several computational methods have been developed with the aim to: (i) model and better understand the human drug metabolism; and (ii) enhance the experimental investigation of the metabolism of small xenobiotic molecules. The main predictive tools these methods employ are rule-based approaches, quantitative structure metabolism/activity relationships and docking approaches. This review paper provides detailed metabolic profiles of the major clusters of antihypertensive agents, including their metabolites and their metabolizing enzymes, and it also provides specific information concerning the computational approaches that have been used to predict the metabolic profile of several antihypertensive drugs. PMID:25341854

  3. The role of human carboxylesterases in drug metabolism: have we overlooked their importance?

    PubMed Central

    Laizure, S. Casey; Herring, Vanessa; Hu, Zheyi; Witbrodt, Kevin; Parker, Robert B.

    2012-01-01

    Carboxylesterases are a multi-gene family of enzymes widely distributed throughout the body of mammals that catalyze the hydrolysis of esters, amides, thioesters, and carbamates. In humans, two carboxylesterases, hCE1 and hCE2, are important pathways of drug metabolism. Both are expressed in the liver, but levels of hCE1 greatly exceed those of hCE2. In the intestine only high levels of hCE2 are expressed. The most common drug substrates are ester prodrugs specifically designed to enhance oral bioavailability that must be hydrolyzed to their active carboxylic acid by hydrolysis after absorption from the gastrointestinal tract. However, carboxylesterases also play an important role in the hydrolysis of some drugs to inactive metabolites. It has been widely accepted that drugs undergoing hydrolysis by hCE1 and hCE2 are not subject to clinically significant alterations in their disposition, but there is now a significant and growing body of evidence that genetic polymorphisms, drug-drug interactions, drug-disease interactions and other factors are important determinants of the variability in the therapeutic response to carboxylesterase-substrate drugs. The implications for the safe and effective use of drug therapy is far-reaching, as the patient exposure to substrate drugs includes numerous agents from widely prescribed therapeutic classes such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, antiplatelets, HMG-CoA inhibitors, antivirals, and central nervous system agents. PMID:23386599

  4. Chemomodulatory effect of Moringa oleifera, Lam, on hepatic carcinogen metabolising enzymes, antioxidant parameters and skin papillomagenesis in mice.

    PubMed

    Bharali, Rupjyoti; Tabassum, Jawahira; Azad, Mohammed Rekibul Haque

    2003-01-01

    The modulatory effects of a hydro-alcoholic extract of drumsticks of Moringa oliefera Lam at doses of 125 mg/kg bodyweight and 250 mg/ kg body weight for 7 and 14 days, respectively, were investigated with reference to drug metabolising Phase I (Cytochrome b(5) and Cytochrome p(450) ) and Phase II (Glutathione-S- transferase) enzymes, anti-oxidant enzymes, glutathione content and lipid peroxidation in the liver of 6-8 week old female Swiss albino mice. Further, the chemopreventive efficacy of the extract was evaluated in a two stage model of 7,12 - dimethylbenz(a)anthracene induced skin papillomagenesis. Significant increase (p<0.05 to p<0.01) in the activities of hepatic cytochrome b(5), cytochrome p(450), catalase, glutathione peroxidase ( GPx ), glutathione reductase (GR), acid soluble sulfhydryl content (-SH ) and a significant decrease ( p<0.01 ) in the hepatic MDA level were observed at both dose levels of treatment when compared with the control values. Glutathione-S- transferase ( GST )activity was found to be significantly increased (p<0.01 ) only at the higher dose level. Butylated hydroxyanisol (BHA ) fed at a dose of 0.75% in the diet for 7 and 14 days (positive control ) caused a significant increase (p<0.05 to p<0.01) in the levels of hepatic phase I and phase II enzymes, anti- oxidant enzymes, glutathione content and a decrease in lipid peroxidation. The skin papillomagenesis studies demonstrated a significant decrease (p<0.05 ) in the percentage of mice with papillomas, average number of papillomas per mouse and papillomas per papilloma bearing mouse when the animals received a topical application of the extract at a dose of 5mg/ kg body weight in the peri-initiation phase 7 days before and 7 days after DMBA application, Group II ), promotional phase (from the day of croton oil application and continued till the end of the experiment, Group III ) and both peri and post initiation stages (from 7 days prior to DMBA application and continued till the

  5. Effects of hepatic enzyme inducers on thyroxine (T4) catabolism in primary rat hepatocytes

    EPA Science Inventory

    Nuclear receptor agonists such as phenobarbital (PB), 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153), and 3-methylcholantrene (3-MC) decrease circulating thyroxine (T4) concentrations in rats. It is suspected that this decrease occurs through the induction of hepatic metabolizing en...

  6. Evaluation of the Novel HISCL Chemiluminescence Enzyme Immunoassay for Laboratory Screening of Hepatitis C Virus.

    PubMed

    Feng, Shu; Wei, Bin; Liu, Qianqian; Wang, Tingting; Li, Dongdong; Rao, Chenli; Tao, Chuanmin; Wang, Lanlan

    2016-07-01

    The hepatitis C virus (HCV) antibody assay remains the first-line screening test to identify HCV infection. The newly arrived HISCL Anti-HCV assay had a satisfactory seroconversion sensitivity. Its sensitivity and specificity were 98.97 and 100% for clinical samples. In general, the HISCL Anti-HCV assay may be a novel choice for clinical HCV screening. PMID:27170643

  7. INFLUENCE OF OZONE AND NITROGEN DIOXIDE ON HEPATIC MICROSOMAL ENZYMES IN MICE

    EPA Science Inventory

    Since ambient concentrations of ozone and nitrogen dioxide increase drug-induced sleeping time in female mice, potential mechanisms were sought by investigating the effects of these gases on hepatic microsomal mixed-function oxidases in female CD-1 mice. Exposure to ozone did not...

  8. A novel method for visualizing nuclear hormone receptor networks relevant to drug metabolism.

    PubMed

    Ekins, Sean; Kirillov, Eugene; Rakhmatulin, Eugene A; Nikolskaya, Tatiana

    2005-03-01

    The increasing generation of biological data represents a challenge to understanding the complexity of systems, resulting in scientists increasingly focused on a relatively narrow area of study, thereby limiting insight that can be gained from a broader perspective. In the field of drug metabolism and toxicology we are witnessing the characterization of many proteins. Most of the key enzymes and transporters are recognized as transcriptionally regulated by the nuclear hormone receptors such as pregnane X receptor, constitutive androstane receptor, vitamin D receptor, glucocorticoid receptor, and others. There is apparent cross talk in regulation, since multiple receptors may modulate expression of a single enzyme or transporter, representing one of many areas of active research interest. We have used published data on nuclear hormone receptors, enzymes, ligands, and other biological information to manually annotate an Oracle database, forming the basis of a platform for querying (MetaDrug). Using algorithms, we have demonstrated how nuclear hormone receptors alone can form a network of direct interactions, and when expanded, this network increases in complexity to describe the interactions with target genes as well as small molecules known to bind a receptor, enzyme, or transporter. We have also described how the database can be used for visualizing high-throughput microarray data derived from a published study of MCF-7 cells treated with 4-hydroxytamoxifen, to highlight potential downstream effects of molecule treatment. The database represents a novel knowledge mining and analytical tool that, to be relevant, requires continual updating to evolve alongside other key storage systems and sources of biological knowledge. PMID:15608136

  9. Targeting Cellular Squalene Synthase, an Enzyme Essential for Cholesterol Biosynthesis, Is a Potential Antiviral Strategy against Hepatitis C Virus

    PubMed Central

    Saito, Kyoko; Shirasago, Yoshitaka; Suzuki, Tetsuro; Aizaki, Hideki; Hanada, Kentaro; Wakita, Takaji; Nishijima, Masahiro

    2014-01-01

    ABSTRACT Hepatitis C virus (HCV) exploits host membrane cholesterol and its metabolism for progeny virus production. Here, we examined the impact of targeting cellular squalene synthase (SQS), the first committed enzyme for cholesterol biosynthesis, on HCV production. By using the HCV JFH-1 strain and human hepatoma Huh-7.5.1-derived cells, we found that the SQS inhibitors YM-53601 and zaragozic acid A decreased viral RNA, protein, and progeny production in HCV-infected cells without affecting cell viability. Similarly, small interfering RNA (siRNA)-mediated knockdown of SQS led to significantly reduced HCV production, confirming the enzyme as an antiviral target. A metabolic labeling study demonstrated that YM-53601 suppressed the biosynthesis of cholesterol and cholesteryl esters at antiviral concentrations. Unlike YM-53601, the cholesterol esterification inhibitor Sandoz 58-035 did not exhibit an antiviral effect, suggesting that biosynthesis of cholesterol is more important than that of cholesteryl esters for HCV production. YM-53601 inhibited transient replication of a JFH-1 subgenomic replicon and entry of JFH-1 pseudoparticles, suggesting that at least suppression of viral RNA replication and entry contributes to the antiviral effect of the drug. Collectively, our findings highlight the importance of the cholesterol biosynthetic pathway in HCV production and implicate SQS as a potential target for antiviral strategies against HCV. IMPORTANCE Hepatitis C virus (HCV) is known to be closely associated with host cholesterol and its metabolism throughout the viral life cycle. However, the impact of targeting cholesterol biosynthetic enzymes on HCV production is not fully understood. We found that squalene synthase, the first committed enzyme for cholesterol biosynthesis, is important for HCV production, and we propose this enzyme as a potential anti-HCV target. We provide evidence that synthesis of free cholesterol is more important than that of esterified

  10. Hepatic effects of phthalate esters.

    PubMed Central

    Seth, P K

    1982-01-01

    Di(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer and microchemical environmental pollutant, produces subtle changes in hepatic function as judged by increase in liver weight and morphological and biochemical alterations. It can modify the biological response of drugs and other xenobiotics. Such interactions appear to occur at the pharmacokinetic phase, as DEHP was found to alter the activity of microsomal drug-metabolizing enzymes and ethanol metabolism. DEHP produced a time- and route-dependent effect on the hepatic cytochrome P-450 contents and activity of aminopyrine N-demethylase, aniline hydroxylase, alcohol dehydrogenase and high and low Km aldehyde dehydrogenases when given orally or intraperitoneally. Under in vitro conditions, DEHP produced no effect on the activity of aminopyrine N-demethylase or aniline hydroxylase, while mono(2-ethylhexyl) phthalate (MEHP) and 2-ethylhexanol (2-EH) significantly inhibited their activity at concentrations ranging from 2.5 to 15.0 mM. Activity of aminopyrine N-demethylase and aniline hydroxylase was also inhibited by dimethyl phthalate (DMP) and dibutyl phthalate (DBP) after a single oral administration. In view of the possibility of the human exposure to phthalates and other xenobiotics simultaneously, these observations are of great significance. PMID:6754361

  11. Activity-based protein profiling identifies a host enzyme, carboxylesterase 1, which is differentially active during hepatitis C virus replication.

    PubMed

    Blais, David R; Lyn, Rodney K; Joyce, Michael A; Rouleau, Yanouchka; Steenbergen, Rineke; Barsby, Nicola; Zhu, Lin-Fu; Pegoraro, Adrian F; Stolow, Albert; Tyrrell, David L; Pezacki, John Paul

    2010-08-13

    Hepatitis C virus (HCV) relies on many interactions with host cell proteins for propagation. Successful HCV infection also requires enzymatic activity of host cell enzymes for key post-translational modifications. To identify such enzymes, we have applied activity-based protein profiling to examine the activity of serine hydrolases during HCV replication. Profiling of hydrolases in Huh7 cells replicating HCV identified CES1 (carboxylesterase 1) as a differentially active enzyme. CES1 is an endogenous liver protein involved in processing of triglycerides and cholesterol. We observe that CES1 expression and activity were altered in the presence of HCV. The knockdown of CES1 with siRNA resulted in lower levels of HCV replication, and up-regulation of CES1 was observed to favor HCV propagation, implying an important role for this host cell protein. Experiments in HCV JFH1-infected cells suggest that CES1 facilitates HCV release because less intracellular HCV core protein was observed, whereas HCV titers remained high. CES1 activity was observed to increase the size and density of lipid droplets, which are necessary for the maturation of very low density lipoproteins, one of the likely vehicles for HCV release. In transgenic mice containing human-mouse chimeric livers, HCV infection also correlates with higher levels of endogenous CES1, providing further evidence that CES1 has an important role in HCV propagation. PMID:20530478

  12. Effects of dietary pantethine levels on drug-metabolizing system in the liver of rats orally administered varying amounts of autoxidized linoleate.

    PubMed

    Hiramatsu, N; Kishida, T; Natake, M

    1989-08-01

    The effects of dietary pantethine levels on the drug-metabolizing system were investigated under administration of varying amounts of autoxidized linoleate (AL) with rat liver microsomes and S-9 fractions. AL having 800 meq/kg of peroxide value and 1,700 meq/kg of carbonyl value was dosed to the rats of each group given drinking water containing 0 mg% (deficient), 6.25 mg% (normal), and 125 mg% pantethine (sufficient). The contents and activities of the enzymes in the drug-metabolizing system in the rat liver of each pantethine-level group changed essentially in a similar manner, that is, they were induced at an AL daily dose of 0.2 ml/100 g body weight (i.e., small dose) for 5 successive days and lowered at a daily dose of 0.4 ml/100 g body weight (i.e., large dose) by the same administration period, compared with respective non-AL groups in each of the three pantethine levels. In both non-AL and the small-dose AL, enzyme activities of the electron transfer system in rat liver microsomes, aminopyrine-N-demethylase activity, and metabolic activation of 2-acetylaminofluorene in S-9 fractions were significantly higher in the pantethine-deficient group than in the pantethine-normal and -sufficient groups. In the large-dose AL, the enzyme activities in the drug-metabolizing system decreased significantly in any pantethine levels, though the survival rate of the rats was higher in the pantethine-sufficient group than in the pantethine-normal groups. The results suggest that the pantethine relieves the effect of dosed AL on the drug-metabolizing system in rat liver. PMID:2585150

  13. Alteration of human hepatic drug transporter activity and expression by cigarette smoke condensate.

    PubMed

    Sayyed, Katia; Vee, Marc Le; Abdel-Razzak, Ziad; Jouan, Elodie; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Fardel, Olivier

    2016-07-01

    Smoking is well-known to impair pharmacokinetics, through inducing expression of drug metabolizing enzymes. In the present study, we demonstrated that cigarette smoke condensate (CSC) also alters activity and expression of hepatic drug transporters, which are now recognized as major actors of hepatobiliary elimination of drugs. CSC thus directly inhibited activities of sinusoidal transporters such as OATP1B1, OATP1B3, OCT1 and NTCP as well as those of canalicular transporters like P-glycoprotein, MRP2, BCRP and MATE1, in hepatic transporters-overexpressing cells. CSC similarly counteracted constitutive OATP, NTCP and OCT1 activities in human highly-differentiated hepatic HepaRG cells. In parallel, CSC induced expression of BCRP at both mRNA and protein level in HepaRG cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B1, OATP2B1, OAT2, NTCP, OCT1 and BSEP, and enhanced that of MRP4. Such changes in transporter gene expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin, a reference activator of the aryl hydrocarbon receptor (AhR) pathway, and were counteracted, for some of them, by siRNA-mediated AhR silencing. This suggests that CSC alters hepatic drug transporter levels via activation of the AhR cascade. Importantly, drug transporter expression regulations as well as some transporter activity inhibitions occurred for a range of CSC concentrations similar to those required for inducing drug metabolizing enzymes and may therefore be hypothesized to be relevant for smokers. Taken together, these data established human hepatic transporters as targets of cigarette smoke, which could contribute to known alteration of pharmacokinetics and some liver adverse effects caused by smoking. PMID:27450509

  14. Effect of Antiviral Therapy on Serum Activity of Angiotensin Converting Enzyme in Patients with Chronic Hepatitis C

    PubMed Central

    Husic-Selimovic, Azra; Sofic, Amela; Huskic, Jasminko; Bulja, Deniz

    2016-01-01

    Introduction: Renin-angiotenzin system (RAS) is frequently activated in patients with chronic liver disease. Angiotenzin - II (AT-II), produced by angiotenzin converting enzyme (ACE), has many physiological effects, including an important role in liver fibrogenesis. Combined antiviral therapy with PEG-IFN and ribavirin besides its antiviral effect also leads to a reduction in liver parenchyma fibrosis. Aim of the study: Determining the value of ACE in serum of patients with chronic hepatitis C before and after combined antiviral therapy, as well as the value of ACE activities in sera of the control group. Materials and methods: We studied 50 patients treated at Gastroenterohepatology Department, in the time-period of four years. Value of ACE in serum was determined by Olympus AU 400 device, with application of kit “Infinity TN ACE Liquid Stable Reagent”. HCV RNA levels in sera were measured by real time PCR. HCV RNA test was performed with modular analysis of AMPLICOR and COBAS AMPLICOR HCV MONITOR test v2.0, which has proved infection and was used for quantification of the viruses and monitoring of the patients’ response to therapy. Liver histology was evaluated in accordance with the level of necroinflammation activity and stage of fibrosis. Results: Serum activities of ACE in chronic hepatitis C patients is statistically higher than the values in the control group (p=0.02). Antiviral therapy in chronic hepatitis C patients statistically decreases serum activities of ACE (p= 0.02) and indirectly affects fibrogenesis of the liver parenchyma. Correlation between ACE and ALT activity after the therapy was proved (0.3934). Conclusion: Our findings suggest that the activity of ACE in serum is a good indirect parameter of the liver damage, and could be used as an indirect prognostic factor of the level of liver parenchyma damage. Serum activity of ACE can be used as a parameter for non-invasive assessment of intensity of liver damage. PMID:27147779

  15. The Action of Antidiabetic Plants of the Canadian James Bay Cree Traditional Pharmacopeia on Key Enzymes of Hepatic Glucose Homeostasis

    PubMed Central

    Nachar, Abir; Vallerand, Diane; Musallam, Lina; Lavoie, Louis; Arnason, John; Haddad, Pierre S.

    2013-01-01

    We determined the capacity of putative antidiabetic plants used by the Eastern James Bay Cree (Canada) to modulate key enzymes of gluconeogenesis and glycogen synthesis and key regulating kinases. Glucose-6-phosphatase (G6Pase) and glycogen synthase (GS) activities were assessed in cultured hepatocytes treated with crude extracts of seventeen plant species. Phosphorylation of AMP-dependent protein kinase (AMPK), Akt, and Glycogen synthase kinase-3 (GSK-3) were probed by Western blot. Seven of the seventeen plant extracts significantly decreased G6Pase activity, Abies balsamea and Picea glauca, exerting an effect similar to insulin. This action involved both Akt and AMPK phosphorylation. On the other hand, several plant extracts activated GS, Larix laricina and A. balsamea, far exceeding the action of insulin. We also found a significant correlation between GS stimulation and GSK-3 phosphorylation induced by plant extract treatments. In summary, three Cree plants stand out for marked effects on hepatic glucose homeostasis. P. glauca affects glucose production whereas L. laricina rather acts on glucose storage. However, A. balsamea has the most promising profile, simultaneously and powerfully reducing G6Pase and stimulating GS. Our studies thus confirm that the reduction of hepatic glucose production likely contributes to the therapeutic potential of several antidiabetic Cree traditional medicines. PMID:23864882

  16. Incorporation of in vitro drug metabolism data into physiologically-based pharmacokinetic models.

    PubMed

    Houston, J B; Carlile, D J

    1997-10-01

    The liver poses particular problems in constructing physiologically-based pharmacokinetic models since this organ is not only a distribution site for drugs/chemicals but frequently the major site of metabolism. The impact of hepatic drug metabolism in modelling is substantial and it is crucial to the success of the model that in vitro data on biotransformation be incorporated in a judicious manner. The value of in vitro/in vivo extrapolation is clearly demonstrated by considering kinetic data from incubations with freshly isolated hepatocytes. The determination of easily measurable in vitro parameters, such as V(max) and K(m), from initial rate studies and scaling to the in vivo situation by accounting for hepatocellularity provides intrinsic clearance estimates. A scaling factor of 1200 x 10(6) cells per 250 g rat has proved to be a robust parameter independent of laboratory technique and insensitive to animal pretreatment. Similar procedures can also be adopted for other in vitro systems such as hepatic microsomes and liver slices. An appropriate scaling factor for microsomal studies is the microsomal recovery index which allows for the incomplete recovery of cytochrome P-450 with standard differential centrifugation of liver homogenates. The hepatocellularity of a liver slice has been unsatisfactory in scaling kinetic parameters from liver slices. The level of success varies from drug to drug and substrate diffusion is a competing process to metabolism within the slice incubation system; hence, low clearance drugs are better predicted than high clearance drugs. The use of three liver models (venous-equilibration, undistributed sinusoidal and dispersion models) have been compared to predict hepatic clearance from in vitro intrinsic clearance values. As no consistent advantage of one model over the others could be demonstrated, the simplest, the venous-equilibration model, is adequate for the currently available data in hepatocytes. While these successes are

  17. Effect of squalene synthase inhibition on the expression of hepatic cholesterol biosynthetic enzymes, LDL receptor, and cholesterol 7 alpha hydroxylase.

    PubMed

    Ness, G C; Zhao, Z; Keller, R K

    1994-06-01

    Squalene synthase catalyzes the committed step in the biosynthesis of sterols. Treating rats with zaragozic acid A, a potent inhibitor of squalene synthase, caused marked increases in hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, squalene synthase, and LDL receptor mRNA levels. The increase in HMG-CoA reductase mRNA fully accounted for the increases seen in enzyme protein and activity. Farnesyl pyrophosphate synthase mRNA and activity were only slightly increased by zaragozic acid A, while cholesterol 7 alpha hydroxylase mRNA levels were decreased substantially. When rats were pretreated with zaragozic acid A, there was no change in mRNA levels for the cholesterol biosynthetic enzymes or cholesterol 7 alpha hydroxylase upon subsequent treatment with mevalonolactone. Under these same conditions, the enzymatic activity of HMG-CoA reductase was also unaffected. Mevalonolactone treatment reduced the zaragozic acid A-mediated increase in hepatic LDL receptor mRNA levels. Feeding cholesterol eliminated the zaragozic acid A-induced increase in HMG-CoA reductase mRNA levels. These results suggest that inhibition of squalene synthase decreases the level of a squalene-derived regulatory product, resulting in altered amounts of several mRNAs and coordinate increases in HMG-CoA reductase mRNA, protein, and activity. The increase in HMG-CoA reductase gene expression was closely related to the degree of inhibition of cholesterol synthesis caused by zaragozic acid A. PMID:7911291

  18. Exercise training down-regulates hepatic lipogenic enzymes in meal-fed rats: fructose versus complex-carbohydrate diets.

    PubMed

    Fiebig, R; Griffiths, M A; Gore, M T; Baker, D H; Oscai, L; Ney, D M; Ji, L L

    1998-05-01

    The maximal activity and mRNA abundance of hepatic fatty acid synthase (FAS) and other lipogenic enzymes were investigated in rats meal-fed either a high fructose (F) or a high cornstarch (C) diet. The diet contained 50% F or C (g/100 g), casein (20%), cornstarch (16.13%), corn oil (5%), minerals (5.37%), vitamins (1%) and Solka-floc (2%). Female Sprague-Dawley rats (n = 44) were randomly divided into C or F groups that were meal-fed for 3 h/d; each group was subdivided into exercise-trained (T) and untrained (U) groups. Treadmill training was performed 4 h after the initiation of the meal at 25 m/min, 10% grade for 2 h/d, 5 d/wk, for 10 wk. Rats were killed 9 h after the meal and 27 h after the last training session. F-fed rats had significantly higher activities of all lipogenic enzymes assayed and mRNA abundance of FAS and acetyl-coenzyme A carboxylase (ACC) than C rats (P < 0.05). Concentrations of plasma insulin and glucose and liver pyruvate were not altered by F feeding. Proportions of the fatty acids 18:2 and 20:4 were lower, whereas those of 16:0 and 16:1 were higher, in livers of F than of C rats (P < 0.05). Training decreased FAS activity by 50% (P < 0.05), without affecting FAS mRNA level in C rats; this down-regulation was absent in the F rats. ACC mRNA abundance tended to be lower in CT than in CU rats (P < 0.075). L-Type pyruvate kinase activity was lower in FT than in FU rats (P < 0.05), whereas other lipogenic enzyme activities did not differ between T and U rats of each diet group. We conclude that hepatic lipogenic enzyme induction by high carbohydrate meal feeding may be inhibited by exercise training and that a fructose-rich diet may attenuate this training-induced down-regulation. PMID:9566986

  19. Antidiabetic efficacy of citronellol, a citrus monoterpene by ameliorating the hepatic key enzymes of carbohydrate metabolism in streptozotocin-induced diabetic rats.

    PubMed

    Srinivasan, Subramani; Muruganathan, Udaiyar

    2016-04-25

    Diabetes mellitus is a clinically complex disease characterized by chronic hyperglycemia with metabolic disturbances. During diabetes, endogenous hepatic glucose production is increased as a result of impaired activities of the key enzymes of carbohydrate metabolism. The purpose of the present study was to evaluate the antidiabetic efficacy of citronellol, a citrus monoterpene in streptozotocin (STZ)-induced diabetic rats. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (40 mg/kg b.w). STZ induced diabetic rats received citronellol orally at the doses of 25, 50, and 100 mg/kg b.w for 30 days. In this study the levels of plasma glucose, insulin, hemoglobin (Hb), glycated hemoglobin (HbA1C), glycogen, and the activities of carbohydrate metabolic enzymes, liver and kidney markers were evaluated. Oral administration of citronellol (50 mg/kg) for 30 days dose dependently improved the levels of insulin, Hb and hepatic glycogen with significant decrease in glucose and HbA1C levels. The altered activities of carbohydrate metabolic enzymes, hepatic and kidney markers were restored to near normal. Citronellol supplement was found to be effective in preserving the normal histological appearance of hepatic cells and insulin-positive β-cells in STZ-rats. Our results suggest that administration of citronellol attenuates the hyperglycemia in the STZ-induced diabetic rats by ameliorating the key carbohydrate metabolic enzymes and could be developed as a functional and nutraceutical ingredient in combating diabetes mellitus. PMID:26944432

  20. A Novel Mathematical Model Describing Adaptive Cellular Drug Metabolism and Toxicity in the Chemoimmune System

    PubMed Central

    Tóth, Attila; Brózik, Anna; Szakács, Gergely; Sarkadi, Balázs; Hegedüs, Tamás

    2015-01-01

    Cells cope with the threat of xenobiotic stress by activating a complex molecular network that recognizes and eliminates chemically diverse toxic compounds. This “chemoimmune system” consists of cellular Phase I and Phase II metabolic enzymes, Phase 0 and Phase III ATP Binding Cassette (ABC) membrane transporters, and nuclear receptors regulating these components. In order to provide a systems biology characterization of the chemoimmune network, we designed a reaction kinetic model based on differential equations describing Phase 0–III participants and regulatory elements, and characterized cellular fitness to evaluate toxicity. In spite of the simplifications, the model recapitulates changes associated with acquired drug resistance and allows toxicity predictions under variable protein expression and xenobiotic exposure conditions. Our simulations suggest that multidrug ABC transporters at Phase 0 significantly facilitate the defense function of successive network members by lowering intracellular drug concentrations. The model was extended with a novel toxicity framework which opened the possibility of performing in silico cytotoxicity assays. The alterations of the in silico cytotoxicity curves show good agreement with in vitro cell killing experiments. The behavior of the simplified kinetic model suggests that it can serve as a basis for more complex models to efficiently predict xenobiotic and drug metabolism for human medical applications. PMID:25699998

  1. Mammalian flavin-containing monooxygenases: structure/function, genetic polymorphisms and role in drug metabolism

    PubMed Central

    Krueger, Sharon K.; Williams, David E.

    2005-01-01

    Flavin-containing monooxygenase (FMO) oxygenates drugs and xenobiotics containing a “soft-nucleophile”, usually nitrogen or sulfur. FMO, like cytochrome P450 (CYP), is a monooxygenase, utilizing the reducing equivalents of NADPH to reduce 1 atom of molecular oxygen to water, while the other atom is used to oxidize the substrate. FMO and CYP also exhibit similar tissue and cellular location, molecular weight, substrate specificity, and exist as multiple enzymes under developmental control. The human FMO functional gene family is much smaller (5 families each with a single member) than CYP. FMO does not require a reductase to transfer electrons from NADPH and the catalytic cycle of the 2 monooxygenases is strikingly different. Another distinction is the lack of induction of FMOs by xenobiotics. In general, CYP is the major contributor to oxidative xenobiotic metabolism. However, FMO activity may be of significance in a number of cases and should not be overlooked. FMO and CYP have overlapping substrate specificities, but often yield distinct metabolites with potentially significant toxicological/pharmacological consequences. The physiological function(s) of FMO are poorly understood. Three of the 5 expressed human FMO genes, FMO1, FMO2 and FMO3, exhibit genetic polymorphisms. The most studied of these is FMO3 (adult human liver) in which mutant alleles contribute to the disease known as trimethylaminuria. The consequences of these FMO genetic polymorphisms in drug metabolism and human health are areas of research requiring further exploration. PMID:15922018

  2. Hepatic Enzyme's Reference Intervals and Their Modulating Factors in Western Indian Population.

    PubMed

    Maksane, Shalini N; Dandekar, Sucheta P; Shukla, Akash; Bhatia, Shobna

    2016-03-01

    The reference intervals (RIs) of serum aminotransferases and Gamma-glutamyl transferase (GGT) have been established many years ago. Recent RIs are not available. The prospective study was conducted to re-evaluate the RIs of liver enzymes and the effect of demographic and anthropometric variables on them in western Indian population. A total of 1059 blood donors comprised the study population. Anthropometry and serum liver enzymes levels were measured. Subjects were categorized into normal weight and overweight by using body mass index (BMI) and waist circumference (WC). For RI determination, non-parametric methodology recommended by IFCC/CLSI was adopted. Mann-Whitney test and Spearman's rank correlation were used for statistical analysis. Upper limit of normal reference value of liver enzymes were lower in female compared to male. (ALT-23.55 F vs 36.00 M, GGT-34.58 F vs 36.20 M) When RI of liver enzymes were calculated according to body mass index, the upper limit of normal of ALT and GGT were higher in overweight group compared to normal weight group. (ALT-38.00 vs 27.00 IU/L and GGT-37.59 vs 35.26 IU/L). In both male and female, liver enzymes correlated significantly with age. WC and BMI were positively correlated with AST, ALT and GGT in both subgroups and the correlation was stronger in male. Demographic factors should be considered for making liver enzyme tests more clinically relevant. Gender based partitioning should be adopted for serum alanine aminotransferase (ALT) and GGT reference values for Western Indian population. PMID:26855497

  3. Hepatic Xenobiotic Metabolizing Enzyme Gene Expression Through the Life Stages of the Mouse

    EPA Science Inventory

    BACKGROUND: Differences in responses to environmental chemicals and drugs between life stages are likely due in part to differences in the expression of xenobiotic metabolizing enzymes and transporters (XMETs). No comprehensive analysis of the mRNA expression of XMETs has been ca...

  4. Chemoprotective influence of Zanthoxylum sps. on hepatic carcinogen metabolizing and antioxidant enzymes and skin papillomagenesis in murine model.

    PubMed

    Rajamani, Paulraj; Banerjeet, Sanjeev; Rao, A Ramesha

    2011-11-01

    In the present study, the putative potential of pericarp of dried fruit of Zanthoxylum (Rutaceae Family), a common spice additive in India's west coast cuisines, in protecting against carcinogenesis has been reported. Extract from dried fruit of Zanthoxylum was orally administered to mice at two dose levels: 100 and 200 mg/kg body wt. for 14 days. Results reveal bifunctional nature of Zanthoxylum species as deduced from its potential to induce phase-I and phase-II enzyme activities associated with carcinogen activation and detoxification in the liver of mice. Hepatic glutathione S-transferase and DT-diaphorase were found significantly elevated by the treatment. Zanthoxylum was also effective in augmenting the antioxidant enzyme activities of glutathione peroxidase, superoxide dismutase and catalase albeit significantly by high dose of the extract (P < 0.05; P < 0.01). Reduced glutathione was also significantly elevated in the liver of treated animals (P < 0.05). The present study also investigated peri-initiation application of acetone extract of Zanthoxylum on initiated mouse skin. Results showed a significant reduction in tumor incidence from 68% to 36% (P < 0.05); as well as, a reduction in tumor burden per effective mouse from 3.87 to 0.72 (P < 0.01). Cumulatively, the findings strongly suggest cancer chemopreventive potential of Zanthoxylum sps. PMID:22126017

  5. Contaminants in eggs of colonial waterbirds and hepatic cytochrome P450 enzyme levels in pipped tern embryos, Washington State

    USGS Publications Warehouse

    Blus, L.J.; Melancon, M.J.; Hoffman, D.J.; Henny, C.J.

    1998-01-01

    Eggs of Forster's terns (Sterna forsteri) collected in 1991 from nesting colonies on Crescent Island (Columbia River) and the Potholes Reservoir in south central Washington generally contained low residues of organochlorine pesticides and metabolites, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and polychlorinated biphenyls (PCBs). Hepatic cytochrome P450 enzyme activity in pipped embryos of Forster's terns from the two colonies seemed unaffected by contaminants. At Crescent Island, examination of 23 Forster's tern eggs with large embryos (19 viable [10 pipped] and four dead [two pipped]) revealed developmental abnormalities in two viable pipped embryos (missing maxilla and deformed pelvic girdle) and a viable prepipping embryos (shortened beak). Our limited sample sizes and number of compounds analyzed preclude us from determining whether or not the abnormalities are related to contaminants. No abnormalities were noted in 10 pipped eggs (nine viable and one dead at collection) of Forster's terns collected from the Potholes Reservoir colony. Eggs of Caspian terns (Sterna caspia) collected from Crescent Island in 1991 also contained generally low residues of contaminants, only one developmental abnormality was noted, and limited data indicated that cytochrome P450 enzyme activity apparently was unaffected by contaminants. Organochlorine contaminants were generally low in addled eggs of American white pelicans (Pelecanus erythrorhynchos) collected from Crescent Island in 1994

  6. Contaminants in eggs of colonial waterbirds and hepatic cytochrome P450 enzyme levels in pipped tern embryos, Washington State.

    PubMed

    Blus, L J; Melancon, M J; Hoffman, D J; Henny, C J

    1998-10-01

    Eggs of Forster's terns (Sterna forsteri) collected in 1991 from nesting colonies on Crescent Island (Columbia River) and the Potholes Reservoir in south central Washington generally contained low residues of organochlorine pesticides and metabolites, 2,3,7, 8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and polychlorinated biphenyls (PCBs). Hepatic cytochrome P450 enzyme activity in pipped embryos of Forster's terns from the two colonies seemed unaffected by contaminants. At Crescent Island, examination of 23 Forster's tern eggs with large embryos (19 viable [10 pipped] and four dead [two pipped]) revealed developmental abnormalities in two viable pipped embryos (missing maxilla and deformed pelvic girdle) and a viable prepipping embryo (shortened beak). Our limited sample sizes and number of compounds analyzed preclude us from determining whether or not the abnormalities are related to contaminants. No abnormalities were noted in 10 pipped eggs (nine viable and one dead at collection) of Forster's terns collected from the Potholes Reservoir colony. Eggs of Caspian terns (Sterna caspia) collected from Crescent Island in 1991 also contained generally low residues of contaminants, only one developmental abnormality was noted, and limited data indicated that cytochrome P450 enzyme activity apparently was unaffected by contaminants. Organochlorine contaminants were generally low in addled eggs of American white pelicans (Pelecanus erythrorhynchos) collected from Crescent Island in 1994. PMID:9732482

  7. Feline drug metabolism and disposition: pharmacokinetic evidence for species differences and molecular mechanisms

    PubMed Central

    2013-01-01

    Synopsis Although it is widely appreciated that cats respond differently to certain drugs when compared with other companion animal species, the causes of these differences are poorly understood. This review critically evaluates published evidence for altered drug effects in cats, focusing on pharmacokinetic differences between cats, dogs and humans, and the molecular mechanisms underlying these differences. Pharmacokinetic studies indicate that acetaminophen, propofol, carprofen, and acetylsalicylic acid (aspirin) are cleared significantly more slowly in cats versus dogs and humans. All of these drugs are metabolized by conjugation. Cats lack the major phenol UDP-glucuronosyltransferase (UGT) enzymes, including UGT1A6 and UGT1A9, that glucuronidate acetaminophen and propofol. Deficient glucuronidation may also explain slower carprofen clearance, although there is no direct evidence for this. However, poor aspirin clearance in cats appears to be mainly a consequence of slower glycine conjugation. Cats are also deficient in several other conjugation enzymes, including N-acetyltransferase (NAT) 2 and thiopurine methyltransferase (TMPT). NAT2 deficiency may be the reason cats are more prone to developing methemoglobinemia rather than hepatotoxicity from acetaminophen. TMPT deficiency may predispose cats to azathioprine toxicity. No evidence was found for slower elimination of drugs cleared by oxidation or unchanged into urine or bile. Piroxicam, an oxidized drug, was cleared much more rapidly in cats than humans and dogs, although the mechanism for this difference is unclear. More work is needed to better understand drug metabolism and disposition differences in cats, thereby enabling more rational prescribing of existing medications, and the development of safer drugs for this species. PMID:23890237

  8. Arylamine N-acetyltransferases: from drug metabolism and pharmacogenetics to drug discovery.

    PubMed

    Sim, E; Abuhammad, A; Ryan, A

    2014-06-01

    Arylamine N-acetyltransferases (NATs) are polymorphic drug-metabolizing enzymes, acetylating arylamine carcinogens and drugs including hydralazine and sulphonamides. The slow NAT phenotype increases susceptibility to hydralazine and isoniazid toxicity and to occupational bladder cancer. The two polymorphic human NAT loci show linkage disequilibrium. All mammalian Nat genes have an intronless open reading frame and non-coding exons. The human gene products NAT1 and NAT2 have distinct substrate specificities: NAT2 acetylates hydralazine and human NAT1 acetylates p-aminosalicylate (p-AS) and the folate catabolite para-aminobenzoylglutamate (p-abaglu). Human NAT2 is mainly in liver and gut. Human NAT1 and its murine homologue are in many adult tissues and in early embryos. Human NAT1 is strongly expressed in oestrogen receptor-positive breast cancer and may contribute to folate and acetyl CoA homeostasis. NAT enzymes act through a catalytic triad of Cys, His and Asp with the architecture of the active site-modulating specificity. Polymorphisms may cause unfolded protein. The C-terminus helps bind acetyl CoA and differs among NATs including prokaryotic homologues. NAT in Salmonella typhimurium supports carcinogen activation and NAT in mycobacteria metabolizes isoniazid with polymorphism a minor factor in isoniazid resistance. Importantly, nat is in a gene cluster essential for Mycobacterium tuberculosis survival inside macrophages. NAT inhibitors are a starting point for novel anti-tuberculosis drugs. Human NAT1-specific inhibitors may act in biomarker detection in breast cancer and in cancer therapy. NAT inhibitors for co-administration with 5-aminosalicylate (5-AS) in inflammatory bowel disease has prompted ongoing investigations of azoreductases in gut bacteria which release 5-AS from prodrugs including balsalazide. PMID:24467436

  9. Arylamine N-acetyltransferases: from drug metabolism and pharmacogenetics to drug discovery

    PubMed Central

    Sim, E; Abuhammad, A; Ryan, A

    2014-01-01

    Arylamine N-acetyltransferases (NATs) are polymorphic drug-metabolizing enzymes, acetylating arylamine carcinogens and drugs including hydralazine and sulphonamides. The slow NAT phenotype increases susceptibility to hydralazine and isoniazid toxicity and to occupational bladder cancer. The two polymorphic human NAT loci show linkage disequilibrium. All mammalian Nat genes have an intronless open reading frame and non-coding exons. The human gene products NAT1 and NAT2 have distinct substrate specificities: NAT2 acetylates hydralazine and human NAT1 acetylates p-aminosalicylate (p-AS) and the folate catabolite para-aminobenzoylglutamate (p-abaglu). Human NAT2 is mainly in liver and gut. Human NAT1 and its murine homologue are in many adult tissues and in early embryos. Human NAT1 is strongly expressed in oestrogen receptor-positive breast cancer and may contribute to folate and acetyl CoA homeostasis. NAT enzymes act through a catalytic triad of Cys, His and Asp with the architecture of the active site-modulating specificity. Polymorphisms may cause unfolded protein. The C-terminus helps bind acetyl CoA and differs among NATs including prokaryotic homologues. NAT in Salmonella typhimurium supports carcinogen activation and NAT in mycobacteria metabolizes isoniazid with polymorphism a minor factor in isoniazid resistance. Importantly, nat is in a gene cluster essential for Mycobacterium tuberculosis survival inside macrophages. NAT inhibitors are a starting point for novel anti-tuberculosis drugs. Human NAT1-specific inhibitors may act in biomarker detection in breast cancer and in cancer therapy. NAT inhibitors for co-administration with 5-aminosalicylate (5-AS) in inflammatory bowel disease has prompted ongoing investigations of azoreductases in gut bacteria which release 5-AS from prodrugs including balsalazide. PMID:24467436

  10. Coral calcium hydride prevents hepatic steatosis in high fat diet-induced obese rats: A potent mitochondrial nutrient and phase II enzyme inducer.

    PubMed

    Hou, Chen; Wang, Yongyao; Zhu, Erkang; Yan, Chunhong; Zhao, Lin; Wang, Xiaojie; Qiu, Yingfeng; Shen, Hui; Sun, Xuejun; Feng, Zhihui; Liu, Jiankang; Long, Jiangang

    2016-03-01

    Diet-induced nonalcoholic fatty liver disease (NAFLD) is characterized by profound lipid accumulation and associated with an inflammatory response, oxidative stress and hepatic mitochondrial dysfunction. We previously demonstrated that some mitochondrial nutrients effectively ameliorated high fat diet (HFD)-induced hepatic steatosis and metabolic disorders. Molecular hydrogen in hydrogen-rich liquid or inhaling gas, which has been confirmed in scavenging reactive oxygen species and preventing mitochondrial decay, improved metabolic syndrome in patients and animal models. Coral calcium hydride (CCH) is a new solid molecular hydrogen carrier made of coral calcium. However, whether and how CCH impacts HFD-induced hepatic steatosis remains uninvestigated. In the present study, we applied CCH to a HFD-induced NAFLD rat model for 13 weeks. We found that CCH durably generated hydrogen in vivo and in vitro. CCH treatment significantly reduced body weight gain, improved glucose and lipid metabolism and attenuated hepatic steatosis in HFD-induced obese rats with no influence on food and water intake. Moreover, CCH effectively improved HFD-induced hepatic mitochondrial dysfunction, reduced oxidative stress, and activated phase II enzymes. Our results suggest that CCH is an efficient hydrogen-rich agent, which could prevent HFD-induced NAFLD via activating phase II enzymes and improving mitochondrial function. PMID:26774456

  11. Short-term fasting induces intra-hepatic lipid accumulation and decreases intestinal mass without reduced brush-border enzyme activity in mink (Mustela vison) small intestine.

    PubMed

    Bjornvad, C R; Elnif, J; Sangild, P T

    2004-11-01

    For many mammalian species short-term fasting is associated with intestinal atrophy and decreased digestive capacity. Under natural conditions, strictly carnivorous animals often experience prey scarcity during winter, and they may therefore be particularly well adapted to short-term food deprivation. To examine how the carnivorous gastrointestinal tract is affected by fasting, small-intestinal structure, brush-border enzyme activities and hepatic structure and function were examined in fed mink (controls) and mink that had been fasted for 1-10 days. During the first 1-2 days of fasting, intestinal mass decreased more rapidly than total body mass and villus heights were reduced 25-40%. In contrast, tissue-specific activity of the brush-border enzymes sucrase, maltase, lactase, aminopeptidase A and dipeptidylpeptidase IV increased 0.5- to 1.5-fold at this time, but returned to prefasting levels after 6 days of fasting. After 6-10 days of fasting there was a marked increase in the activity of hepatic enzymes and accumulation of intra-hepatic lipid vacuoles. Thus, mink may be a useful model for studying fasting-induced intestinal atrophy and adaptation as well as mechanisms involved in accumulation of intra-hepatic lipids following food deprivation in strictly carnivorous domestic mammals, such as cats and ferrets. PMID:15503054

  12. Development of a highly sensitive bioluminescent enzyme immunoassay for hepatitis B virus surface antigen capable of detecting divergent mutants.

    PubMed

    Minekawa, Takayuki; Takehara, Shizuka; Takahashi, Masaharu; Okamoto, Hiroaki

    2013-08-01

    Hepatitis B virus (HBV) infections are sometimes overlooked when using commercial kits to measure hepatitis B virus surface antigen (HBsAg) due to their low sensitivities and reactivities to mutant strains of various genotypes. We developed an ultrasensitive bioluminescent enzyme immunoassay (BLEIA) for HBsAg using firefly luciferase, which is adaptable to a variety of HBsAg mutants, by combining four monoclonal antibodies with a polyclonal antibody against HBsAg. The measurement of seroconversion panels showed trace amounts of HBsAg during the early infection phase by the BLEIA because of its high sensitivity of 5 mIU/ml. The BLEIA detected HBsAg as early as did PCR in five of seven series and from 2.1 to 9.4 days earlier than commercial immunoassay methods. During the late infection phase, the BLEIA successfully detected HBsAg even 40 days after the disappearance of HBV DNA and the emergence of antibodies against HBsAg. The HBsAg BLEIA successfully detected all 13 recombinant HBsAg and 45 types of HBsAg mutants with various mutations within amino acids 90 to 164 in the S gene product. Some specimens had higher values determined by the BLEIA than those by a commercial chemiluminescent immunoassay; this suggests that such discrepancies were caused by the dissociation of preS1/preS2 peptides from the particle surface. With its highly sensitive detection of low-titer HBsAg, including various mutants, the HBsAg BLEIA is considered to be useful for the early diagnosis and prevention of HBV infection because of the shorter window of infection prior to detection, which facilitates early prediction of recurrence in HBV-infected individuals. PMID:23761660

  13. Comparative toxicology of tetrachlorobiphenyls in mink and rats. I. Changes in hepatic enzyme activity and smooth endoplasmic reticulum volume

    SciTech Connect

    Gillette, D.M.; Corey, R.D.; Helferich, W.G.; McFarland, J.M.; Lowenstine, L.J.; Moody, D.E.; Hammock, B.D.; Shull, L.R.

    1987-01-01

    Mink have been shown previously to be extraordinarily sensitive to polychlorinated biphenyls (PCBs) and related classes of halogenated hydrocarbons. This study explored several aspects of the acute response of mink to two purified tetrachlorobiphenyl (TCB) congeners and compared their response with that of the rat, a less sensitive and more thoroughly studied species. Young female pastel mink and young female Sprague-Dawley rats received three daily intraperitoneal injections with equimolar doses of either 2,4,2',4'-TCB or 3,4,3',4'-TCB, and were sacrificed after 7 days. Two control groups were used for each species; one was allowed free access to food and the other was pair-fed to the 3,4,3',4'-TCB treatment group. Rats remained clinically normal, while mink treated with 3,4,3',4'-TCB developed severe anorexia, diarrhea, and melena. Both species had significant increases in hepatic cytochrome P-450 content and the characteristic shift in the spectral maxima from 450 to 448 nm in the 3,4,3',4'-TCB- but not in the 2,4,2',4'-TCB-treated animals. Rats but not mink had increased activities of several hepatic monooxygenases in response to both congeners while microsomal epoxide hydrolase was increased in rats after 2,4,2',4'-TCB and in mink after 3,4,3',4'-TCB. Significant increases in the relative volume of smooth endoplasmic reticulum within hepatocytes of 2,4,2',4'-TCB-treated rats but not mink were confirmed by ultrastructural morphometry. Accumulation of both congeners was greater in adipose tissue than in the liver of either species. In both species, concentrations in adipose tissue were much greater for 2,4,2',4'-TCB than for 3,4,3',4'-TCB. PCB toxicosis in mink, as in other species, appeared to be dependent on isomeric arrangement of chlorine substituents. However, unlike other species, the toxicosis was not associated with biochemical or morphological evidence of hepatic enzyme induction.

  14. The pharmacoepigenetics of drug metabolism and transport in breast cancer: review of the literature and in silico analysis.

    PubMed

    Nasr, Rihab; Sleiman, Fatima; Awada, Zeinab; Zgheib, Natalie K

    2016-09-01

    The focus of this manuscript is on DNA methylation and miRNA regulation of drug-metabolizing enzymes and drug transporters involved in the disposition of drugs commonly used in breast cancer. We start with a review of the available scant literature and follow with an in silico analysis of the CpG islands and miRNA binding sites of genes of interest. We make the case that there is room for further research to include more genes and miRNAs despite the extensive sharing of miRNA targets by candidate genes of interest. We also stress on the role of peripheral blood as a source of pharmacoepigenetic biomarkers, and point out the lack of toxicoepigenetic studies in breast cancer. PMID:27561648

  15. Hepatic and extrahepatic distribution of ornithine urea cycle enzymes in holocephalan elephant fish (Callorhinchus milii).

    PubMed

    Takagi, Wataru; Kajimura, Makiko; Bell, Justin D; Toop, Tes; Donald, John A; Hyodo, Susumu

    2012-04-01

    Cartilaginous fish comprise two subclasses, the Holocephali (chimaeras) and Elasmobranchii (sharks, skates and rays). Little is known about osmoregulatory mechanisms in holocephalan fishes except that they conduct urea-based osmoregulation, as in elasmobranchs. In the present study, we examined the ornithine urea cycle (OUC) enzymes that play a role in urea biosynthesis in the holocephalan elephant fish, Callorhinchus milii (cm). We obtained a single mRNA encoding carbamoyl phosphate synthetase III (cmCPSIII) and ornithine transcarbamylase (cmOTC), and two mRNAs encoding glutamine synthetases (cmGSs) and two arginases (cmARGs), respectively. The two cmGSs were structurally and functionally separated into two types: brain/liver/kidney-type cmGS1 and muscle-type cmGS2. Furthermore, two alternatively spliced transcripts with different sizes were found for cmgs1 gene. The longer transcript has a putative mitochondrial targeting signal (MTS) and was predominantly expressed in the liver and kidney. MTS was not found in the short form of cmGS1 and cmGS2. A high mRNA expression and enzyme activities were found in the liver and muscle. Furthermore, in various tissues examined, mRNA levels of all the enzymes except cmCPSIII were significantly increased after hatching. The data show that the liver is the important organ for urea biosynthesis in elephant fish, but, extrahepatic tissues such as the kidney and muscle may also contribute to the urea production. In addition to the role of the extrahepatic tissues and nitrogen metabolism, the molecular and functional characteristics of multiple isoforms of GSs and ARGs are discussed. PMID:22227372

  16. Effect of cadmium, mercury, and zinc on the hepatic microsomal enzymes of Channa punctatus

    SciTech Connect

    Dalal, R.; Bhattacharya, S. )

    1994-06-01

    The increased use of heavy metals like cadmium and mercury in industry and agriculture, and their subsequent intrusion in indeterminate amounts into the environment has caused ecological and biological changes. In vivid contrast, zinc, one of the essential elements, and used in the cosmetic industry, is known to play a pivotal roles in various cellular processes. The seriousness and longevity of these metals in the environment are compounded by the fact that they are non-degradable with significant oxidizing capacity and substantial affinity for electronegative nucleophilic species in proteins and enzymes. Exposure of aquatic animals, especially fish, to these toxic metals for a prolonged period produces an intrinsic toxicity in relation to susceptible organs and/or tissues, although no serious morphological or anatomical changes in the animal or even their feeding behavior may occur. The p-hydroxylation of aniline by aniline hydroxylase (AH) and the N-demethylation of amines to generate formaldehyde (HCHO) by aminopyrine demethylase (APD) are the two oxygen-dependent reactions of microsomal mixed-function oxidase (MFOs) which control the pharmacological and toxicological activities of xenobiotics in mammalian and other species. While both these classical enzymes in fish are reported to demonstrate relatively low specific activity, they are used as criteria for delineating polluted areas. Unlike mammalian species, however, intoxication and interference of MFO enzymes by metal toxicants, especially during prolonged exposure, has not been investigated. The present report describes the results of studies from the concurrent exposure for 28 d to cadmium (CdCl[sub 2]), mercury (HgCl[sub 2]) or zinc (ZnCl[sub 2]) individually, on the AH and APD activities and microsomal protein content in liver of freshwater teleost Channa punctatus.

  17. The NS3 proteinase domain of hepatitis C virus is a zinc-containing enzyme.

    PubMed Central

    Stempniak, M; Hostomska, Z; Nodes, B R; Hostomsky, Z

    1997-01-01

    NS3 proteinase of hepatitis C virus (HCV), contained within the N-terminal domain of the NS3 protein, is a chymotrypsin-like serine proteinase responsible for processing of the nonstructural region of the HCV polyprotein. In this study, we examined the sensitivity of the NS3 proteinase to divalent metal ions, which is unusual behavior for this proteinase class. By using a cell-free coupled transcription-translation system, we found that HCV polyprotein processing can be activated by Zn2+ (and, to a lesser degree, by Cd2+, Pb2+, and Co2+) and inhibited by Cu2+ and Hg2+ ions. Elemental analysis of the purified NS3 proteinase domain revealed the presence of zinc in an equimolar ratio. The zinc content was unchanged in a mutated NS3 proteinase in which active-site residues His-57 and Ser-139 were replaced with Ala, suggesting that the zinc atom is not directly involved in catalysis but rather may have a structural role. Based on data from site-directed mutagenesis combined with zinc content determination, we propose that Cys-97, Cys-99, Cys-145, and His-149 coordinate the structural zinc in the HCV NS3 proteinase. A similar metal binding motif is found in 2A proteinases of enteroviruses and rhinoviruses, suggesting that these 2A proteinases and HCV NS3 proteinase are structurally related. PMID:9060645

  18. Hepatic enzyme changes in bovine hepatogenous photosensitivity caused by water-damaged alfalfa hay.

    PubMed

    Putnam, M R; Qualls, C W; Rice, L E; Dawson, L J; Edwards, W C

    1986-07-01

    In the winter of 1983, practitioners reported extensive photosensitization in 7 herds of cattle. All herds had a history of having been fed water-damaged alfalfa hay. A cow from one herd was referred to the veterinary teaching hospital at Oklahoma State University. In this herd of approximately 40 adult Polled Herefords, all cattle had had some degree of clinical involvement over the past 4 to 6 weeks. Clinical signs included scaling and erythema of sparsely haired skin, muzzle, and teats, as well as icterus, anorexia, and weight loss. One cow died, and the remaining cattle recovered over an 8- to 10-week period after removal of the hay from the ration. In the referred cow, values for total and conjugated bilirubin, BUN, creatinine, sorbitol dehydrogenase, serum alkaline phosphatase, serum aspartate transaminase, and serum gamma-glutamyl transferase were higher than normal. In the herd of origin, extremely high serum gamma-glutamyl transferase values (180 to 1,400 IU/L) persisted (normal, 2 to 35 IU/L). Feeding the same alfalfa hay to 2 clinically normal cows reproduced the syndrome. The characteristic hepatic lesion was bile duct necrosis, with secondary bile duct hyperplasia. PMID:2874123

  19. Piezotronic-effect enhanced drug metabolism and sensing on a single ZnO nanowire surface with the presence of human cytochrome P450.

    PubMed

    Wang, Ning; Gao, Caizhen; Xue, Fei; Han, Yu; Li, Tao; Cao, Xia; Zhang, Xueji; Zhang, Yue; Wang, Zhong Lin

    2015-03-24

    Cytochromes P450 (CYPs) enzymes are involved in catalyzing the metabolism of various endogenous and exogenous compounds. A rapid analysis of drug metabolism reactions by CYPs is required because they can metabolize 95% of current drugs in drug development and effective therapies. Here, we describe a study of piezotronic-effect enhanced drug metabolism and sensing by utilizing a single ZnO nanowire (ZnO NW) device. Owing to the unique hydrophobic feature of a ZnO NW that provides a desirable "microenvironment" for the immobilization of biomolecules, our device can effectively stimulate the tolbutamide metabolism by decorating a ZnO NW with cytochrome P4502C9/CYPs reductase (CYP2C9/CPR) microsomes. By applying an external compressive strain to the ZnO nanowire, the piezotronic effect, which plays a primary role in tuning the transport behavior of a ZnO NW utilizing the created piezoelectric polarization charges at the local interface, can effectively enhance the performance of the device. A theoretical model is proposed using an energy band diagram to explain the experimental data. This study provides a potential approach to study drug metabolism and trace drug detection based on the piezotronic effect. PMID:25758259

  20. Measuring Drug Metabolism Kinetics and Drug-Drug Interactions Using Self-Assembled Monolayers for Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry.

    PubMed

    Anderson, Lyndsey L; Berns, Eric J; Bugga, Pradeep; George, Alfred L; Mrksich, Milan

    2016-09-01

    The competition of two drugs for the same metabolizing enzyme is a common mechanism for drug-drug interactions that can lead to altered kinetics in drug metabolism and altered elimination rates in vivo. With the prevalence of multidrug therapy, there is great potential for serious drug-drug interactions and adverse drug reactions. In an effort to prevent adverse drug reactions, the FDA mandates the evaluation of the potential for metabolic inhibition by every new chemical entity. Conventional methods for assaying drug metabolism (e.g., those based on HPLC) have been established for measuring drug-drug interactions; however, they are low-throughput. Here we describe an approach to measure the catalytic activity of CYP2C9 using the high-throughput technique self-assembled monolayers for matrix-assisted laser desorption-ionization (SAMDI) mass spectrometry. We measured the kinetics of CYP450 metabolism of the substrate, screened a set of drugs for inhibition of CYP2C9 and determined the Ki values for inhibitors. The throughput of this platform may enable drug metabolism and drug-drug interactions to be interrogated at a scale that cannot be achieved with current methods. PMID:27467208

  1. Hepatic enzyme activity after combined administration of methylmercury, lead and cadmium in the pekin duck

    SciTech Connect

    Jordan, S.A.; Bhatnagar, M.K. )

    1990-04-01

    In order to assess adequately the environmental impact of heavy metals it is important to consider that they may occur simultaneously in the environment, where they may interact to alter their individual toxicities on living systems. Metals such as mercury (Hg), lead (Pb) and cadmium (Cd) can be found in all levels of the polluted ecosystem, and in animals inhabiting such areas. In the polluted aquatic environment waterfowl have been noted to accumulate high levels of these metals in their tissues. A major toxic manifestation of heavy metal exposure is the perturbation of a wide range of enzyme systems in virtually all subcellular compartments. With the exception of lead, little data is available on the effects of metals on avian enzyme systems. The present report describes the effects observed in vivo on acid phosphatase (AP), glutathione S-transferase (GST) and cytochrome c oxidase (cyt c ox) in the liver of pekin ducks exposed to combinations of methylmercury (MeHg), lead and cadmium.

  2. Vitamin D Enhances the Efficacy of Irinotecan through miR-627-Mediated Inhibition of Intratumoral Drug Metabolism.

    PubMed

    Sun, Meiyan; Zhang, Qunshu; Yang, Xiaoyu; Qian, Steven Y; Guo, Bin

    2016-09-01

    Cytochrome P450 enzyme CYP3A4 is an important drug-metabolizing enzyme, and high levels of tumoral expression of CYP3A4 are linked to drug resistance. We investigated the function of vitamin D-regulated miR-627 in intratumoral CYP3A4 suppression and its role in enhancing the efficacy of chemotherapy. We found that miR-627 targets CYP3A4 and suppresses CYP3A4 expression in colon cancer cell lines. Furthermore, calcitriol (the active form of vitamin D) suppressed CYP3A4 expression by activating miR-627. As a result, calcitriol inhibited CYP3A4-mediated metabolism of irinotecan (a topoisomerase I inhibitor) in cancer cells. We show that calcitriol enhanced the efficacy of irinotecan in growth inhibition and apoptosis induction. When miR-627 is inhibited, calcitriol fails to enhance the activity of irinotecan. In addition, overexpression of miR-627 or siRNA knockdown of CYP3A4 enhanced the efficacy of irinotecan in growth inhibition and apoptosis induction. In contrast, overexpression of CYP3A4 abolished the effects of calcitriol on the activity of irinotecan. Using a nude mouse xenograft model, we demonstrated that calcitriol inhibited CYP3A4 and enhanced the in vivo antitumor activity of irinotecan without causing side effects. Our study identified a novel target for improving cancer therapy, i.e., modulating the intratumoral CYP3A4-mediated drug metabolism with vitamin D. This strategy could enhance the therapeutic efficacy without eliciting the side effects. Mol Cancer Ther; 15(9); 2086-95. ©2016 AACR. PMID:27458137

  3. Age-Related Changes in Hepatic Function: An Update on Implications for Drug Therapy.

    PubMed

    Tan, Joseph L; Eastment, Jacques G; Poudel, Arjun; Hubbard, Ruth E

    2015-12-01

    The accumulation of deficits with increasing age results in a decline in the functional capacity of multiple organs and systems. These changes can have a significant influence on the pharmacokinetics and pharmacodynamics of prescribed drugs. Although alterations in body composition and worsening renal clearance are important considerations, for most drugs the liver has the greatest effect on metabolism. Age-related change in hepatic function thereby causes much of the variability in older people's responses to medication. In this review, we propose that a decline in the ability of the liver to inactivate toxins may contribute to a proinflammatory state in which frailty can develop. Since inflammation also downregulates drug metabolism, medication prescribed to frail older people in accordance with disease-specific guidelines may undergo reduced systemic clearance, leading to adverse drug reactions, further functional decline and increasing polypharmacy, exacerbating rather than ameliorating frailty status. We also describe how increasing chronological age and frailty status impact liver size, blood flow and protein binding and enzymes of drug metabolism. This is used to contextualise our discussion of appropriate prescribing practices. For example, while the general axiom of 'start low, go slow' should underpin the initiation of medication (titrating to a defined therapeutic goal), it is important to consider whether drug clearance is flow or capacity-limited. By summarising the effect of age-related changes in hepatic function on medications commonly used in older people, we aim to provide a guide that will have high clinical utility for practising geriatricians. PMID:26547855

  4. Development of gold-immobilized P450 platform for exploring the effect of oligomer formation on P450-mediated metabolism for in vitro to in vivo drug metabolism predictions

    NASA Astrophysics Data System (ADS)

    Kabulski, Jarod L.

    The cytochrome P450 (P450) enzyme family is responsible for the biotransformation of a wide range of endogenous and xenobiotic compounds, as well as being the major metabolic enzyme in first pass drug metabolism. In vivo drug metabolism for P450 enzymes is predicted using in vitro data obtained from a reconstituted expressed P450 system, but these systems have not always been proven to accurately represent in vivo enzyme kinetics, due to interactions caused by oligomer formation. These in vitro systems use soluble P450 enzymes prone to oligomer formation and studies have shown that increased states of protein aggregation directly affect the P450 enzyme kinetics. We have developed an immobilized enzyme system that isolates the enzyme and can be used to elucidate the effect of P450 aggregation on metabolism kinetics. The long term goal of my research is to develop a tool that will help improve the assessment of pharmaceuticals by better predicting in vivo kinetics in an in vitro system. The central hypothesis of this research is that P450-mediated kinetics measured in vitro is dependent on oligomer formation and that the accurate prediction of in vivo P450-mediated kinetics requires elucidation of the effect of oligomer formation. The rationale is that the development of a P450 bound to a Au platform can be used to control the aggregation of enzymes and bonding to Au may also permit replacement of the natural redox partners with an electrode capable of supplying a constant flow of electrons. This dissertation explains the details of the enzyme attachment, monitoring substrate binding, and metabolism using physiological and electrochemical methods, determination of enzyme kinetics, and the development of an immobilized-P450 enzyme bioreactor. This work provides alternative approaches to studying P450-mediated kinetics, a platform for controlling enzyme aggregation, electrochemically-driven P450 metabolism, and for investigating the effect of protein

  5. Eletriptan metabolism by human hepatic CYP450 enzymes and transport by human P-glycoprotein.

    PubMed

    Evans, David C; O'Connor, Desmond; Lake, Brian G; Evers, Raymond; Allen, Christopher; Hargreaves, Richard

    2003-07-01

    "Reaction phenotyping" studies were performed with eletriptan (ETT) to determine its propensity to interact with coadministered medications. Its ability to serve as a substrate for human P-glycoprotein (P-gp) was also investigated since a central mechanism of action has been proposed for this "triptan" class of drug. In studies with a characterized bank of human liver microsome preparations, a good correlation (r2 = 0.932) was obtained between formation of N-desmethyl eletriptan (DETT) and CYP3A4-catalyzed testosterone 6 beta-hydroxylation. DETT was selected to be monitored in our studies since it represents a significant ETT metabolite in humans, circulating at concentrations 10 to 20% of those observed for parent drug. ETT was metabolized to DETT by recombinant CYP2D6 (rCYP2D6) and rCYP3A4, and to a lesser extent by rCYP2C9 and rCYP2C19. The metabolism of ETT to DETT in human liver microsomes was markedly inhibited by troleandomycin, erythromycin, miconazole, and an inhibitory antibody to CYP3A4, but not by inhibitors of other major P450 enzymes. ETT had little inhibitory effect on any of the P450 enzymes investigated. ETT was determined to be a good substrate for human P-gp in vitro. In bidirectional transport studies across LLC-MDR1 and LLC-Mdr1a cell monolayers, ETT had a BA/AB transport ratio in the range 9 to 11. This finding had significance in vivo since brain exposure to ETT was reduced 40-fold in Mdr1a+/+ relative to Mdr1a-/- mice. ETT metabolism to DETT is therefore catalyzed primarily by CYP3A4, and plasma concentrations are expected to be increased when coadministered with inhibitors of CYP3A4 and P-gp activity. PMID:12814962

  6. Characterization of hepatic enzyme activity in older adults with dementia: potential impact on personalizing pharmacotherapy

    PubMed Central

    Campbell, Noll L; Skaar, Todd C; Perkins, Anthony J; Gao, Sujuan; Li, Lang; Khan, Babar A; Boustani, Malaz A

    2015-01-01

    Objective To determine the frequency of pharmacogenomic variants and concurrent medications that may alter the efficacy and tolerability of acetylcholinesterase inhibitors (AChEIs). Materials and methods A multisite cross-sectional study was carried out across four memory care practices in the greater Indianapolis area. Participants were adults aged 65 years and older with a diagnosis of probable or possible Alzheimer’s disease (AD) (n=105). Blood samples and self-reported medication data were collected. Since two of the three AChEIs are metabolized by cytochrome P450 (CYP)-2D6, we determined the frequency of functional genetic variants in the CYP2D6 gene and calculated their predicted CYP2D6-activity scores. Concurrent medication data were collected from self-reported medication surveys, and their predicted effect on the pharmacokinetics of AChEIs was determined based on their known effects on CYP2D6 and CYP3A4/5 enzyme activities. Results Among the 105 subjects enrolled, 72% were female and 36% were African American. Subjects had a mean age of 79.6 years. The population used a mean of eight medications per day (prescription and nonprescription). The CYP2D6 activity score frequencies were 0 (3.8%), 0.5 (4.8%), 1.0 (36.2%), 1.5–2.0 (51.4%), and >2.0 (3.8%). Nineteen subjects (18.1%) used a medication considered a strong or moderate inhibitor of CYP2D6, and eight subjects (7.6%) used a medication considered a strong or moderate inhibitor of CYP3A4/5. In total, 28.6% of the study population was predicted to have reduced activity of the CYP2D6 or CYP3A4/5 enzymes due to either genetic variants or concomitant medications. Conclusion Both pharmacogenetic variants and concurrent drug therapies that are predicted to alter the pharmacokinetics of AChEIs should be evaluated in older adults with AD. Pharmacogenetic and drug-interaction data may help personalize AD therapy and increase adherence by improving tolerability. PMID:25609939

  7. Update Information on Drug Metabolism Systems—2009, Part II

    PubMed Central

    Rendic, S.; Guengerich, F.P.

    2014-01-01

    The present paper is an update of the data on the effects of diseases and environmental factors on the expression and/or activity of human cytochrome P450 (CYP) enzymes and transporters. The data are presented in tabular form (Tables 1 and 2) and are a continuation of previously published summaries on the effects of drugs and other chemicals on CYP enzymes. The collected information presented here is as stated by the cited author(s), and in cases when several references are cited the latest published information is included. Inconsistent results and conclusions obtained by different authors are highlighted, followed by discussion of the major findings. The searchable database is available as an Excel file, for information about file availability contact the corresponding author. PMID:20302566

  8. Genetic polymorphisms analysis of drug-metabolizing enzyme CYP2C9 in the Uyghur population.

    PubMed

    Jin, Tianbo; Xun, Xiaojie; Du, Shuli; Geng, Tingting; Wang, Hong; Feng, Tian; Chen, Chen; Yuan, Dongya; Kang, Longli

    2016-08-01

    Genetic variations in cytochrome P450 2C9 are known to contribute to interindividual and interethnic variability in response to clinical drugs, but little is known about the genetic variation of CYP2C9 in the Uyghur population. We directly sequenced the whole CYP2C9 gene in 96 unrelated, healthy Uyghur from Xinjiang Uygur Autonomous Region of China and screened for genetic variants in the promoter, exons, introns and 3'-UTR. Thirty five previously reported alleles and six genotypes were detected in this study. The allele frequencies of CYP2C9*1, *2, *11, *12, *29 and *33 were 89.58, 7.81, 0.52, 0.52, 1.04 and 0.52%, respectively. We detected one non-synonymous novel variant at position 329 from Arg to Cys and this mutation is predicted to be intolerant by SIFT. Our results provide basic information about CYP2C9 alleles in Uyghur, which may help to optimize pharmacotherapy effectiveness by providing personalized medicine to this ethnic group. PMID:26610168

  9. Micropatterned coculture of hepatocytes on electrospun fibers as a potential in vitro model for predictive drug metabolism.

    PubMed

    Liu, Yaowen; Wei, Jiaojun; Lu, Jinfu; Lei, Dongmei; Yan, Shili; Li, Xiaohong

    2016-06-01

    The liver is the major organ of importance to determine drug dispositions in the body, thus the development of hepatocyte culture systems is of great scientific and practical interests to provide reliable and predictable models for in vitro drug screening. In the current study, to address the challenges of a rapid function loss of primary hepatocytes, the coculture of hepatocytes with fibroblasts and endothelial cells (Hep-Fib-EC) was established on micropatterned fibrous scaffolds. Liver-specific functions, such as the albumin secretion and urea synthesis, were well maintained in the coculture system, accompanied by a rapid formation of multicellular hepatocyte spheroids. The activities of phase I (CYP3A11 and CYP2C9) and phase II enzymes indicated a gradual increase for cocultured hepatocytes, and a maximum level was achieved after 5 days and maintained throughout 15 days of culture. The metabolism testing on model drugs indicated that the scaled clearance rates for hepatocytes in the Hep-Fib-EC coculture system were significantly higher than those of other culture methods, and a linear regression analysis indicated good correlations between the observed data of rats and in vitro predicted values during 15 days of culture. In addition, the enzyme activities and drug clearance rates of hepatocytes in the Hep-Fib-EC coculture model experienced sensitive responsiveness to the inducers and inhibitors of metabolizing enzymes. These results demonstrated the feasibility of micropatterned coculture of hepatocytes as a potential in vitro testing model for the prediction of in vivo drug metabolism. PMID:27040241

  10. Effect of Aerobic and Resistance Exercise Training on Liver Enzymes and Hepatic Fat in Iranian Men With Nonalcoholic Fatty Liver Disease

    PubMed Central

    Shamsoddini, Alireza; Sobhani, Vahid; Ghamar Chehreh, Mohammad Ebrahim; Alavian, Seyed Moayed; Zaree, Ali

    2015-01-01

    Background: Nonalcoholic fatty liver disease (NAFLD) has different prevalence rates in various parts of the world and is a risk factor for diabetes and cardiovascular disease that could progress to nonalcoholic steatohepatitis, cirrhosis, and liver failure. Objectives: The current study aimed to investigate the effect of Aerobic Training (AT) and resistance training (RT) on hepatic fat content and liver enzyme levels in Iranian men. Patients and Methods: In a randomized clinical trial study, 30 men with clinically defined NAFLD were allocated into three groups (aerobic, resistance and control). An aerobic group program consisted of 45 minutes of aerobic exercise at 60% - 75% maximum heart rate intensity, a resistance group performed seven resistance exercises at intensity of 50% - 70% of 1 repetition maximum (1RM ) and the control group had no exercise training program during the study. Before and after training, anthropometry, insulin sensitivity, liver enzymes and hepatic fat were elevated. Results: After training, hepatic fat content was markedly reduced, to a similar extent, in both the aerobic and resistance exercise training groups (P ≤ 0.05). In the two exercise training groups, alanine amino transferase and aspartate amino transferase serum levels were significantly decreased compared to the control group (P = 0.002) and (P = 0.02), respectively. Moreover, body fat (%), fat mass (kg), homeostasis model assessment insulin resistance (HOMI-IR) were all improved in the AT and RT. These changes in the AT group were independent of weight loss. Conclusions: This study demonstrated that RT and AT are equally effective in reducing hepatic fat content and liver enzyme levels among patients with NAFLD. However, aerobic exercise specifically improves NAFLD independent of any change in body weight. PMID:26587039

  11. Monitoring and managing hepatic disease in anaesthesia.

    PubMed

    Kiamanesh, D; Rumley, J; Moitra, V K

    2013-12-01

    Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy. PMID:24335399

  12. Fisetin improves glucose homeostasis through the inhibition of gluconeogenic enzymes in hepatic tissues of streptozotocin induced diabetic rats.

    PubMed

    Prasath, Gopalan Sriram; Pillai, Subramanian Iyyam; Subramanian, Sorimuthu Pillai

    2014-10-01

    Liver plays a vital role in blood glucose homeostasis. Recent studies have provided considerable evidence that hepatic glucose production (HGP) plays an important role in the development of fasting hyperglycemia in diabetes. From this perspective, diminution of HGP has certainly been considered for the treatment of diabetes. In the present study, we have analyzed the modulatory effects of fisetin, a flavonoid of strawberries, on the expression of key enzymes of carbohydrate metabolism in STZ induced experimental diabetic rats. The physiological criterions such as food and fluid intake were regularly monitored. The levels of blood glucose, plasma insulin, hemoglobin and glycosylated hemoglobin were analyzed. The mRNA and protein expression levels of gluconeogenic genes such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were determined by immunoblot as well as PCR analysis. Diabetic group of rats showed significant increase in food and water intake when compared with control group of rats. Upon oral administration of fisetin as well as gliclazide to diabetic group of rats, the levels were found to be decreased. Oral administration of fisetin (10 mg/kg body weight) to diabetic rats for 30 days established a significant decline in blood glucose and glycosylated hemoglobin levels and a significant increase in plasma insulin level. The mRNA and protein expression levels of gluconeogenic genes, such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), were decreased in liver tissues upon treatment with fisetin. The results of the present study suggest that fisetin improves glucose homeostasis by direct inhibition of gluconeogenesis in liver. PMID:25064342

  13. Diurnal Variations of Mouse Plasma and Hepatic Bile Acid Concentrations as well as Expression of Biosynthetic Enzymes and Transporters

    PubMed Central

    Zhang, Yu-Kun Jennifer; Guo, Grace L.; Klaassen, Curtis D.

    2011-01-01

    Background Diurnal fluctuation of bile acid (BA) concentrations in the enterohepatic system of mammals has been known for a long time. Recently, BAs have been recognized as signaling molecules beyond their well-established roles in dietary lipid absorption and cholesterol homeostasis. Methods and Results The current study depicted diurnal variations of individual BAs detected by ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) in serum and livers collected from C57BL/6 mice fed a regular chow or a chow containing cholestyramine (resin). Circadian rhythms of mRNA of vital BA-related nuclear receptors, enzymes, and transporters in livers and ilea were determined in control- and resin-fed mice, as well as in farnesoid X receptor (FXR) null mice. The circadian profiles of BAs showed enhanced bacterial dehydroxylation during the fasting phase and efficient hepatic reconjugation of BAs in the fed phase. The resin removed more than 90% of BAs with β-hydroxy groups, such as muricholic acids and ursodeoxycholic acid, from serum and livers, but did not exert as significant influence on CA and CDCA in both compartments. Both resin-fed and FXR-null mouse models indicate that BAs regulate their own biosynthesis through the FXR-regulated ileal fibroblast growth factor 15. BA flux also influences the daily mRNA levels of multiple BA transporters. Conclusion BA concentration and composition exhibit circadian variations in mouse liver and serum, which influences the circadian rhythms of BA metabolizing genes in liver and ileum. The diurnal variations of BAs appear to serve as a signal that coordinates daily nutrient metabolism in mammals. PMID:21346810

  14. Characterization of human liver enzymes involved in the biotransformation of boceprevir, a hepatitis C virus protease inhibitor.

    PubMed

    Ghosal, Anima; Yuan, Yuan; Tong, Wei; Su, Ai-Duen; Gu, Chunyan; Chowdhury, Swapan K; Kishnani, Narendra S; Alton, Kevin B

    2011-03-01

    Boceprevir (SCH 503034), a protease inhibitor, is under clinical development for the treatment of human hepatitis C virus infections. In human liver microsomes, formation of oxidative metabolites after incubations with [(14)C]boceprevir was catalyzed by CYP3A4 and CYP3A5. In addition, the highest turnover was observed in recombinant CYP3A4 and CYP3A5. After a single radiolabeled dose to human, boceprevir was subjected to two distinct pathways, namely cytochrome P450-mediated oxidation and ketone reduction. Therefore, attempts were made to identify the enzymes responsible for the formation of carbonyl-reduced metabolites. Human liver S9 and cytosol converted ∼ 28 and ∼ 68% of boceprevir to M28, respectively, in the presence of an NADPH-generating system. Screening of boceprevir with recombinant human aldo-keto reductases (AKRs) revealed that AKR1C2 and AKR1C3 exhibited catalytic activity with respect to the formation of M+2 metabolites (M28 and M31). The formation of M28 was inhibited by 100 μM flufenamic acid (80.3%), 200 μM mefenamic acid (83.7%), and 100 μM phenolphthalein (86.1%), known inhibitors of AKRs, suggesting its formation through carbonyl reduction pathway. Formation of M28 was also inhibited by 100 μM diazepam (75.1%), 1 mM ibuprofen (70%), and 200 μM diflunisal (89.4%). These data demonstrated that CYP3A4 and CYP3A5 are primarily responsible for the formation of oxidative metabolites and the formation of M28 and M31, the keto-reduced metabolites, are most likely mediated by AKR1C2 and AKR1C3. Because the biotransformation and clearance of boceprevir involves two different enzymatic pathways, boceprevir is less likely to be a victim of significant drug-drug interaction with concomitant medication affecting either of these pathways. PMID:21123164

  15. Effect of Boswellia serrata supplementation on blood lipid, hepatic enzymes and fructosamine levels in type2 diabetic patients

    PubMed Central

    2014-01-01

    Background Type 2 diabetes is an endocrine disorder that affects a large percentage of patients. High blood glucose causes fatty deposits in the liver which is likely to increase in SGOT and SGPT activities. Significant increase in SGOT/SGPT and low HDL levels is observed in patients with diabetes. Serum fructosamine concentration reflects the degree of blood glucose control in diabetic patients. This study was aimed to investigate the antidiabetic, hypolipidemic and hepatoprotective effects of supplementation of Boswellia serrata in type2 diabetic patients. Methods 60 type 2 diabetic patients from both sexes (30 males and 30 females) were dedicated to the control and intervention groups (30 subjects per group). Boswellia serrata gum resin in amount of 900 mg daily for 6 weeks were orally administered (as three 300 mg doses) in intervention group and the control group did not receive anything. Blood samples were taken at the beginning of the study and after 6 weeks. Blood levels of fructosamine, lipid profiles as well as hepatic enzyme in type 2 diabetic patients were measured. Results Treatment of diabetic patient with Boswellia serrata was caused to significant increase in blood HDL levels as well as a remarkable decrease in cholesterol, LDL, fructosamine (p < 0.05) SGPT and SGOT levels after 6 weeks (p < 0.01). In spite of reduction of serum triglyceride, VLDL levels in intervention group, we did not detect a significant difference after 6 weeks. Conclusion This study showed that Boswellia serrata supplementation can be beneficial in controlling blood parameters in patients with type 2 diabetes. Therefore, its use can be useful in patients with medicines. PMID:24495344

  16. Lack of effect of spinal anesthesia on drug metabolism

    SciTech Connect

    Whelan, E.; Wood, A.J.; Shay, S.; Wood, M. )

    1989-09-01

    The effect of spinal anesthesia on drug disposition was determined in six dogs with chronically implanted vascular catheters using propranolol as a model compound. On the first study day, 40 mg of unlabeled propranolol and 200 microCi of (3H)propranolol were injected into the portal and femoral veins respectively. Arterial blood samples were taken for 4 hr for measurement of plasma concentrations of labeled and unlabeled propranolol by high-pressure liquid chromatography (HPLC) and of (3H)propranolol by liquid scintillation counting of the HPLC eluant corresponding to each propranolol peak. Twenty-four hr later, spinal anesthesia was induced with tetracaine (mean dose 20.7 +/- 0.6 mg) with low sacral to midthoracic levels and the propranolol infusions and sampling were then repeated. Spinal anesthesia had no significant effect on either the intrinsic clearance of propranolol (2.01 +/- 0.75 L/min before and 1.9 +/- 0.7 L/min during spinal anesthesia), or on mean hepatic plasma flow (2.01 +/- 0.5 L/min before and 1.93 +/- 0.5 L/min during spinal anesthesia). The systemic clearance and elimination half-life of propranolol were also unchanged by spinal anesthesia (0.9 +/- 0.23 L/min on the first day, 0.7 +/- 0.1 L/min during spinal anesthesia; and 101 +/- 21 min on the first day, 115 +/- 16 min during spinal anesthesia, respectively). The volume of distribution (Vd) of propranolol was similarly unaffected by spinal anesthesia.

  17. Alterations in hepatic mRNA expression of phase II enzymes and xenobiotic transporters after targeted disruption of hepatocyte nuclear factor 4 alpha.

    PubMed

    Lu, Hong; Gonzalez, Frank J; Klaassen, Curtis

    2010-12-01

    Hepatocyte nuclear factor 4 alpha (HNF4a) is a liver-enriched master regulator of liver function. HNF4a is important in regulating hepatic expression of certain cytochrome P450s. The purpose of this study was to use mice lacking HNF4a expression in liver (HNF4a-HNull) to elucidate the role of HNF4a in regulating hepatic expression of phase II enzymes and transporters in mice. Compared with male wild-type mice, HNF4a-HNull male mouse livers had (1) markedly lower messenger RNAs (mRNAs) encoding the uptake transporters sodium taurocholate cotransporting polypeptide, organic anion transporting polypeptide (Oatp) 1a1, Oatp2b1, organic anion transporter 2, sodium phosphate cotransporter type 1, sulfate anion transporter 1, sodium-dependent vitamin C transporter 1, the phase II enzymes Uridine 5'-diphospho (UDP)-glucuronosyltransferase (Ugt) 2a3, Ugt2b1, Ugt3a1, Ugt3a2, sulfotransferase (Sult) 1a1, Sult1b1, Sult5a1, the efflux transporters multidrug resistance-associated protein (Mrp) 6, and multidrug and toxin extrusion 1; (2) moderately lower mRNAs encoding Oatp1b2, organic cation transporter (Oct) 1, Ugt1a5, Ugt1a9, glutathione S-transferase (Gst) m4, Gstm6, and breast cancer resistance protein; but (3) higher mRNAs encoding Oatp1a4, Octn2, Ugt1a1, Sult1e1, Sult2a2, Gsta4, Gstm1-m3, multidrug resistance protein (Mdr) 1a, Mrp3, and Mrp4. Hepatic signaling of nuclear factor E2-related factor 2 and pregnane X receptor appear to be activated in HNF4a-HNull mice. In conclusion, HNF4a deficiency markedly alters hepatic mRNA expression of a large number of phase II enzymes and transporters, probably because of the loss of HNF4a, which is a transactivator and a determinant of gender-specific expression and/or adaptive activation of signaling pathways important in hepatic regulation of these phase II enzymes and transporters. PMID:20935164

  18. Suppression of Hepatic Cyp1a2 by Total Ginsenosides in Lipopolysaccharide-Treated Mice and Primary Mouse Hepatocytes.

    PubMed

    Sun, Haiyan; Yan, Yijing; Xu, Chenshu; Wan, Hongxia; Liu, Dong

    2016-03-23

    The roots of Panax ginseng (ginseng) have been extensively used in traditional Chinese medicine. However, herb-drug interactions between ginseng and other co-administered drugs are not fully understood concerning the effect of ginseng on drug metabolism and clearance. The current study aimed to elucidate the effect of total ginsenosides, a typical ginseng extract, on the regulation of Cyp1a2, a key enzyme to regulate drug metabolism under the normal and inflammatory conditions in mice. Female C57BL/6J mice treated with vehicle and lipopolysaccharide (LPS) were intragastrically administered ginseng extract for 7 days before hepatic P450 expression was analyzed. Primary mouse hepatocytes were also employed to further explore the effects of total ginsenosides on Cyp1a2 expression. The results showed that total ginsenosides in P. ginseng extract exhibited a concentration-dependent suppression on Cyp1a2 mRNA and protein level in both mice and primary mouse hepatocytes. Notably, the inhibitory effects of total ginsenosides on Cyp1a2 mRNA and protein expression were further enhanced following LPS treatment. Therefore, future research is warranted to investigate the role of ginsenosides in the regulation of hepatic CYP450s. Moreover, consumption of ginseng as food or supplement should be monitored for patients on combinational therapy, especially those with inflammatory diseases. PMID:26923348

  19. Applications of mass spectrometry in drug metabolism: 50 years of progress.

    PubMed

    Wen, Bo; Zhu, Mingshe

    2015-02-01

    Mass spectrometry plays a pivotal role in drug metabolism studies, which are an integral part of drug discovery and development nowadays. Metabolite identification has become critical to understanding the metabolic fate of drug candidates and to aid lead optimization with improved metabolic stability, toxicology and efficacy profiles. Ever since the introduction of atmospheric ionization techniques in the early 1990s, liquid chromatography coupled with mass spectrometry (LC/MS) has secured a central role as the predominant analytical platform for metabolite identification as LC and MS technologies continually advanced. In this review, we discuss the evolution of both MS technology and its applications over the past 50 years to meet the increasing demand of drug metabolism studies. These advances include ionization sources, mass analyzers, a wide range of MS acquisition strategies and data mining tools that have substantially accelerated the metabolite identification process and changed the overall drug metabolism landscape. Exemplary applications for characterization and identification of both small-molecule xenobiotics and biological macromolecules are described. In addition, this review discusses novel MS technologies and applications, including xenobiotic metabolomics that hold additional promise for advancing drug metabolism research, and offers thoughts on remaining challenges in studying the metabolism and disposition of drugs and other xenobiotics. PMID:25639893

  20. Bimodal targeting of microsomal cytochrome P450s to mitochondria: implications in drug metabolism and toxicity

    PubMed Central

    Sangar, Michelle C; Bansal, Seema

    2010-01-01

    Importance of the field Microsomal cytochrome P450s are critical for drug metabolism and toxicity. Recent studies show that these CYPs are also present in the mitochondrial compartment of human and rodent tissues. Mitochondrial CYP1A1 and 2E1 show both overlapping and distinct metabolic activities compared to microsomal forms. Mitochondrial CYP2E1 also induces oxidative stress. The mechanisms of mitochondria targeting of CYPs and their role in drug metabolism and toxicity are important factors to consider while determining the drug dose and in drug development. Areas covered in this review This review highlights the mechanisms of bimodal targeting of CYP1A1, 2B1, 2E1 and 2D6 to mitochondria and microsomes. The review also discusses differences in structure and function of mitochondrial CYPs. What the readers will gain A comprehensive review of the literature on drug metabolism in the mitochondrial compartment, and their potential for inducing mitochondrial dysfunction. Take home message Studies on the biochemistry, pharmacology and pharmacogenetic analysis of CYPs are mostly focused on the molecular forms associated with the microsomal membrane. However, the mitochondrial CYPs in some individuals can represent a substantial part of the tissue pool and contribute in a significant way to drug metabolism, clearance and toxicity. PMID:20629582

  1. Regulatory effects of testosterone and 17 beta-oestradiol on the metabolism of dimethylnitrosamine by renal and hepatic microsomal enzymes from BALB/c mice.

    PubMed

    Ampy, F R; Asseffa, A

    1988-01-01

    Previous investigations with BALB/c mice have demonstrated that no sex-related differences exist in the ability of liver microsomal fractions (S-9) to biotransform dimethylnitrosamine (DMN) to its active mutagenic metabolites as evidenced by bacterial screening assays. In contrast, kidney microsomal enzymes from adult male BALB/c mice and not from females, castrates, and immature animals, were capable of activating DMN. The present study was designed to test the effects of testosterone and oestradiol on DMN bioactivation by hepatic or renal microsomal enzymes. Mutagenic assays were performed using liver and kidney microsomal enzymes with the histidine deficient mutant Salmonella typhimurium TA100. Results indicate that testosterone treatment of female BALB/c mice resulted in an increase in the ability of their renal microsomal enzymes to metabolize DMN to its active mutagenic intermediates. Renal microsomal enzymes from female mice treated with 17 beta-oestradiol had no effect on DMN metabolism. However, the ability of the renal microsomal enzymes treated with 17 beta-oestradiol to bioactivate DMN was significantly decreased in males. PMID:3229148

  2. Relative potency based on hepatic enzyme induction predicts immunosuppressive effects of a mixture of PCDDS/PCDFS and PCBS

    SciTech Connect

    Smialowicz, R.J.; DeVito, M.J. Williams, W.C.; Birnbaum, L.S.

    2008-03-15

    The toxic equivalency factor (TEF) approach was employed to compare immunotoxic potency of mixtures containing polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), using the antibody response to sheep erythrocytes (SRBC). Mixture-1 (MIX-1) contained TCDD, 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzofuran (1-PeCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), and 1,2,3,4,6,7,8,9-octachlorodibenzofuran (OCDF). Mixture-2 (MIX-2) contained MIX-1 and the following PCBs, 3,3',4,4'-tetrachlorobiphenyl (IUPAC No. 77), 3,3',4,4',5-pentachlorobiphenyl (126), 3,3',4,4',5,5N-hexachlorobiphenyl (169), 2,3,3',4,4'-pentachlorobiphenyl (105), 2,3',4,4',5-pentachlorobiphenyl (118), and 2,3,3',4,4',5-hexachlorobiphenyl (156). The mixture compositions were based on relative chemical concentrations in food and human tissues. TCDD equivalents (TEQ) of the mixture were estimated using relative potency factors from hepatic enzyme induction in mice [DeVito, M.J., Diliberto, J.J., Ross, D.G., Menache, M.G., Birnbaum, L.S., 1997. Dose-response relationships for polyhalogenated dioxins and dibenzofurans following subchronic treatment in mice. I .CYP1A1 and CYP1A2 enzyme activity in liver, lung and skin. Toxicol. Appl. Pharmacol. 130, 197-208; DeVito, M.J., Menache, G., Diliberto, J.J., Ross, D.G., Birnbaum L.S., 2000. Dose-response relationships for induction of CYP1A1 and CYP1A2 enzyme activity in liver, lung, and skin in female mice following subchronic exposure to polychlorinated biphenyls. Toxicol. Appl. Pharmacol. 167, 157-172] Female mice received 0, 1.5, 15, 150 or 450 ng TCDD/kg/day or approximately 0, 1.5, 15, 150 or 450 ng TEQ/kg/day of MIX-1 or MIX-2 by gavage 5 days per week for 13 weeks. Mice were immunized 3 days after the last exposure and 4 days later, body, spleen, thymus, and liver weights were measured

  3. Influence of dietary substances on intestinal drug metabolism and transport.

    PubMed

    Won, Christina S; Oberlies, Nicholas H; Paine, Mary F

    2010-11-01

    Successful delivery of promising new chemical entities via the oral route is rife with challenges, some of which cannot be explained or foreseen during drug development. Further complicating an already multifaceted problem is the obvious, yet often overlooked, effect of dietary substances on drug disposition and response. Some dietary substances, particularly fruit juices, have been shown to inhibit biochemical processes in the intestine, leading to altered pharmacokinetic (PK), and potentially pharmacodynamic (PD), outcomes. Inhibition of intestinal CYP3Amediated metabolism is the major mechanism by which fruit juices, including grapefruit juice, enhances systemic exposure to new and already marketed drugs. Inhibition of intestinal non-CYP3A enzymes and apically-located transport proteins represent recently identified mechanisms that can alter PK and PD. Several fruit juices have been shown to inhibit these processes in vitro, but some interactions have not translated to the clinic. The lack of in vitroin vivo concordance is due largely to a lack of rigorous methods to elucidate causative ingredients prior to clinical testing. Identification of specific components and underlying mechanisms is challenging, as dietary substances frequently contain multiple, often unknown, bioactive ingredients that vary in composition and bioactivity. A translational research approach, combining expertise from clinical pharmacologists and natural products chemists, is needed to develop robust models describing PK/PD relationships between a given dietary substance and drug of interest. Validation of these models through well-designed clinical trials would facilitate development of common practice guidelines for managing drug-dietary substance interactions appropriately. PMID:21189136

  4. Comparison among Different Gilthead Sea Bream (Sparus aurata) Farming Systems: Activity of Intestinal and Hepatic Enzymes and 13C-NMR Analysis of Lipids

    PubMed Central

    Coco, Laura Del; Papadia, Paride; Pascali, Sandra A. De; Bressani, Giorgia; Storelli, Carlo; Zonno, Vincenzo; Fanizzi, Francesco Paolo

    2009-01-01

    In order to evaluate differences in general health and nutritional values of gilthead sea bream (Sparus aurata), the effects of semi-intensive, land-based tanks and sea-cages intensive rearing systems were investigated, and results compared with captured wild fish. The physiological state was determined by measuring the activity of three different intestinal digestive enzymes: alkaline phosphatase (ALP), leucine aminopeptidase (LAP) and maltase; and the activity of the hepatic ALP. Also, the hepatic content in protein, cholesterol, and lipid were assessed. 13C-NMR analysis for qualitative and quantitative characterization of the lipid fraction extracted from fish muscles for semi-intensive and land based tanks intensive systems was performed. The lipid fraction composition showed small but significant differences in the monounsaturated/saturated fatty acid ratio, with the semi-intensive characterized by higher monounsaturated and lower saturated fatty acid content with respect to land based tanks intensive rearing system. PMID:22253985

  5. The use of isolated enterocytes to study Phase I intestinal drug metabolism: validation with rat and pig intestine.

    PubMed

    Bonnefille, Philippe; Sezgin-Bayindir, Zerrin; Belkhelfa, Haouaria; Arellano, Cécile; Gandia, Peggy; Woodley, John; Houin, Georges

    2011-02-01

    An important step in the development of new drugs is to evaluate the extent of their metabolism during absorption in the small intestine. Reliable in vitro systems to do this can expediate the development process, but the current systems are often unsuitable because they lack the appropriate metabolic enzymes (e.g. Caco-2 cell monolayers) or are not representative of the physiological conditions present in the intact intestinal cells (e.g. isolated microsomes). The aim of this study was to validate the use of isolated intestinal epithelial cells (enterocytes), equivalent to hepatocytes, to evaluate Phase I drug metabolism. A method was developed to prepare enterocytes from rat and pig (as metabolically closer to man) that maintained good viability and activity for up to 90 min as judged by trypan blue exclusion and the release of the cytosolic enzyme lactate dehydrogenase. The Phase I metabolism of the established marker drugs: midazolam, bupropion and dextromethorphan were measured by LC-MS and confirmed the activities of the 3A, 2B and 2D families of CYP isoforms, respectively. The kinetic parameters, K(m) and V(max), were compared between isolated cells and isolated intestinal microsomes from the rat. The use of isolated intestinal cells is a simple and practical method to study the Phase I metabolism of drugs during their absorption and the potential for drug-drug interactions. The method could eventually be modified and usefully applied to human studies. PMID:21121944

  6. INFLUENCE OF DIETARY SUBSTANCES ON INTESTINAL DRUG METABOLISM AND TRANSPORT

    PubMed Central

    Won, Christina S.; Oberlies, Nicholas H.; Paine, Mary F.

    2011-01-01

    Successful delivery of promising new chemical entities via the oral route is rife with challenges, some of which cannot be explained or foreseen during drug development. Further complicating an already multifaceted problem is the obvious, yet often overlooked, effect of dietary substances on drug disposition and response. Some dietary substances, particularly fruit juices, have been shown to inhibit biochemical processes in the intestine, leading to altered pharmacokinetic (PK), and potentially pharmacodynamic (PD), outcomes. Inhibition of intestinal CYP3A-mediated metabolism is the major mechanism by which fruit juices, including grapefruit juice, enhances systemic exposure to new and already marketed drugs. Inhibition of intestinal non-CYP3A enzymes and apically-located transport proteins represent recently identified mechanisms that can alter PK and PD. Several fruit juices have been shown to inhibit these processes in vitro, but some interactions have not translated to the clinic. The lack of in vitro-in vivo concordance is due largely to a lack of rigorous methods to elucidate causative ingredients prior to clinical testing. Identification of specific components and underlying mechanisms is challenging, as dietary substances frequently contain multiple, often unknown, bioactive ingredients that vary in composition and bioactivity. A translational research approach, combining expertise from clinical pharmacologists and natural products chemists, is needed to develop robust models describing PK/PD relationships between a given dietary substance and drug of interest. Validation of these models through well-designed clinical trials would facilitate development of common practice guidelines for managing drug-dietary substance interactions appropriately. PMID:21189136

  7. Effects of alcohol on human carboxylesterase drug metabolism

    PubMed Central

    Parker, Robert B.; Hu, Zhe-Yi; Meibohm, Bernd; Laizure, S. Casey

    2015-01-01

    Background and Objective Human carboxylesterase-1 (CES1) and human carboxylesterase-2 (CES2) play an important role in metabolizing many medications. Alcohol is a known inhibitor of these enzymes but the relative effect on CES1 and CES2 is unknown. The aim of this study is to determine the impact of alcohol on the metabolism of specific probes for CES1 (oseltamivir) and CES2 (aspirin). Methods The effect of alcohol on CES1- and CES2-mediated probe drug hydrolysis was determined in vitro using recombinant human carboxylesterase. To characterize the in vivo effects of alcohol, healthy volunteers received each probe drug alone and in combination with alcohol followed by blood sample collection and determination of oseltamivir, aspirin, and respective metabolite pharmacokinetics. Results Alcohol significantly inhibited oseltamivir hydrolysis by CES1 in vitro but did not affect aspirin metabolism by CES2. Alcohol increased the oseltamivir area under the plasma concentration-time curve (AUC) from 0-6 h by 27% (range 11-46%, p=0.011) and decreased the metabolite/oseltamivir AUC 0-6 h ratio by 34% (range 25-41%, p<0.001). Aspirin pharmacokinetics were not affected by alcohol. Conclusions Alcohol significantly inhibited the hydrolysis of oseltamivir by CES1 both in vitro and in humans, but did not affect the hydrolysis of aspirin to salicylic acid by CES2. These results suggest that alcohol's inhibition of CES1 could potentially result in clinically significant drug interactions with other CES1-substrate drugs, but it is unlikely to significantly affect CES2-substrate drug hydrolysis. PMID:25511794

  8. Modulation of CYP1A1 and CYP1A2 hepatic enzymes after oral administration of Chios mastic gum to male Wistar rats.

    PubMed

    Katsanou, Efrosini S; Kyriakopoulou, Katerina; Emmanouil, Christina; Fokialakis, Nikolas; Skaltsounis, Alexios-Leandros; Machera, Kyriaki

    2014-01-01

    Chios mastic gum (CMG), a resin derived from Pistacia lentiscus var. chia, is known since ancient times for its pharmacological activities. CYP1A1 and CYP1A2 enzymes are among the most involved in the biotransformation of chemicals and the metabolic activation of pro-carcinogens. Previous studies referring to the modulation of these enzymes by CMG have revealed findings of unclear biological and toxicological significance. For this purpose, the modulation of CYP1A1 and CYP1A2 enzymes in the liver of male Wistar rats following oral administration of CMG extract (CMGE), at the levels of mRNA and CYP1A1 enzyme activity, was compared to respective enzyme modulation following oral administration of a well-known bioactive natural product, caffeine, as control compound known to involve hepatic enzymes in its metabolism. mRNA levels of Cyp1a1 and Cyp1a2 were measured by reverse transcription real-time polymerase chain reaction and their relative quantification was calculated. CYP1A1 enzyme induction was measured through the activity of ethoxyresorufin-O-deethylase (EROD). The results indicated that administration of CMGE at the recommended pharmaceutical dose does not induce significant transcriptional modulation of Cyp1a1/2 and subsequent enzyme activity induction of CYP1A1 while effects of the same order of magnitude were observed in the same test system following the administration of caffeine at the mean daily consumed levels. The outcome of this study further confirms the lack of any toxicological or biological significance of the specific findings on liver following the administration of CMGE. PMID:24950217

  9. Possible protective role of pregnenolone-16 alpha-carbonitrile in lithocholic acid-induced hepatotoxicity through enhanced hepatic lipogenesis.

    PubMed

    Miyata, Masaaki; Nomoto, Masahiro; Sotodate, Fumiaki; Mizuki, Tomohiro; Hori, Wataru; Nagayasu, Miho; Yokokawa, Shinya; Ninomiya, Shin-ichi; Yamazoe, Yasushi

    2010-06-25

    Lithocholic acid (LCA) feeding causes both liver parenchymal and cholestatic damages in experimental animals. Although pregnenolone-16 alpha-carbonitrile (PCN)-mediated protection against LCA-induced hepatocyte injury may be explained by induction of drug metabolizing enzymes, the protection from the delayed cholestasis remains incompletely understood. Thus, the PCN-mediated protective mechanism has been studied from the point of modification of lipid metabolism. At an early stage of LCA feeding, an imbalance of biliary bile acid and phospholipid excretion was observed. Co-treatment with PCN reversed the increase in serum alanine aminotransferase (ALT) as well as alkaline phosphatase (ALP) activities and hepatic hydrophobic bile acid levels. LCA feeding decreased hepatic mRNA levels of several fatty acid- and phospholipid-related genes before elevation of serum ALT and ALP activities. On the other hand, PCN co-treatment reversed the decrease in the mRNA levels and hepatic levels of phospholipids, triglycerides and free fatty acids. PCN co-treatment also reversed the decrease in biliary phospholipid output in LCA-fed mice. Treatment with PCN alone increased hepatic phospholipid, triglyceride and free fatty acid concentrations. Hepatic fatty acid and phosphatidylcholine synthetic activities increased in mice treated with PCN alone or PCN and LCA, compared to control mice, whereas these activities decreased in LCA-fed mice. These results suggest the possibility that PCN-mediated stimulation of lipogenesis contributes to the protection from lithocholic acid-induced hepatotoxicity. PMID:20359477

  10. The effect of insulin on plasma glucose concentrations, expression of hepatic glucose transporters and key gluconeogenic enzymes during the perinatal period in broiler chickens.

    PubMed

    Franssens, Lies; Lesuisse, Jens; Wang, Yufeng; Willems, Els; Willemsen, Hilke; Koppenol, Astrid; Guo, Xiaoquan; Buyse, Johan; Decuypere, Eddy; Everaert, Nadia

    2016-06-01

    Chickens have blood glucose concentrations that are twofold higher than those observed in mammals. Moreover, the insulin sensitivity seems to decrease with postnatal age in both broiler and layer chickens. However, little is known about the response of insulin on plasma glucose concentrations and mRNA abundance of hepatic glucose transporters 1, 2, 3, 8, 9 and 12 (GLUT1, 2, 3, 8, 9 and 12) and three regulatory enzymes of the gluconeogenesis, phosphoenolpyruvate carboxykinase 1 and 2 (PCK1 and 2) or fructose-1,6-biphosphatase 1 (FBP1) in chicks during the perinatal period. In the present study, broiler embryos on embryonic day (ED)16, ED18 or newly-hatched broiler chicks were injected intravenously with bovine insulin (1μg/g body weight (BW)) to examine plasma glucose response and changes in hepatic mRNA abundance of the GLUTs, PCK1 and 2 and FBP1. Results were compared with a non-treated control group and a saline-injected sham group. Plasma glucose levels of insulin-treated ED18 embryos recovered faster from their minimum level than those of insulin-treated ED16 embryos or newly-hatched chicks. In addition, at the minimum plasma glucose level seven hours post-injection (PI), hepatic GLUT2, FBP1 and PCK2 mRNA abundance was decreased in insulin-injected embryos, compared to sham and control groups, being most pronounced when insulin injection occurred on ED16. PMID:26723190

  11. Also with a restrictive transfusion policy, screening with second-generation anti-hepatitis C virus enzyme-linked immunosorbent assay would have reduced post-transfusion hepatitis C after open-heart surgery.

    PubMed

    Mathiesen, U L; Karlsson, E; Foberg, U; Frydén, A; Franzén, L; Widell, A; Bodemar, G

    1993-07-01

    The incidence of post-transfusion hepatitis non-A, non-B (PTH-NANB) was prospectively assessed among open-heart surgery patients from the southeast region of Sweden before the introduction of antihepatitis C virus (HCV) blood donor screening. Blood samples for alanine aminotransferase analysis were drawn before and 2, 3, and 4 months after transfusion. Surgery was performed in four centres. Of 190 transfused and followed-up patients 2 (1.1%) contracted PTH-NANB, both operated on at the centre with significantly fewer transfusions than the other centres. One patient had antibodies to HCV detected by first-generation (C100-3) and later by second-generation anti-HCV enzyme-linked immunosorbent assay (ELISA-2) and by positive second-generation recombinant immunoblot assay (4-RIBA). The other patient, although negative by first-generation anti-HCV ELISA, was positive by second-generation ELISA and by 4-RIBA. Both patients were hepatitis C-viremic by polymerase chain reaction (PCR). All the six donors implicated in the two hepatitis cases were first-generation anti-HCV-negative, but two, one for each patient, were positive by second-generation anti-HCV ELISA. This finding was confirmed by positive 4-RIBA in only 1 donor, the other being 'indeterminate'. However, in both donors hepatitis C viremia was found by PCR. This study shows that the second-generation anti-HCV ELISA will further reduce the risk for PTH-NANB/C and draws attention to the problem of evaluation of confirmatory tests. PMID:7689744

  12. HNF4α -- role in drug metabolism and potential drug target?

    PubMed Central

    Hwang-Verslues, Wendy W.; Sladek, Frances M.

    2010-01-01

    Hepatocyte nuclear factor 4α (HNF4α) is a highly conserved member of the nuclear receptor superfamily of ligand-dependent transcription factors. It is best known as a master regulator of liver-specific gene expression, especially those genes involved in lipid transport and glucose metabolism. However, there is also a growing body of work that indicates the importance of HNF4α in the regulation of genes involved in xenobiotic and drug metabolism. A recent study identifying the essential fatty acid linoleic acid (LA, C18:2) as the endogenous, reversible ligand for HNF4α suggests that HNF4α may also be a potential drug target and that its activity may be regulated by diet. This review will discuss the role of HNF4α in drug metabolism, including the genes it regulates, the factors that regulate its activity, and its potential as a drug target. PMID:20833107

  13. Predicting drug metabolism--an evaluation of the expert system METEOR.

    PubMed

    Testa, Bernard; Balmat, Anne-Loyse; Long, Anthony; Judson, Philip

    2005-07-01

    The paper begins with a discussion of the goals of metabolic predictions in early drug research, and some difficulties toward this objective, mainly the various substrate and product selectivities characteristic of drug metabolism. The major in silico approaches to predict drug metabolism are then classified and summarized. A discrimination is, thus, made between 'local' and 'global' systems. In its second part, an evaluation of METEOR, a rule-based expert system used to predict the metabolism of drugs and other xenobiotics, is reported. The published metabolic data of ten substrates were used in this evaluation, the overall results being discussed in terms of correct vs. disputable (i.e., false-positive and false-negative) predictions. The predictions for four representative substrates are presented in detail (Figs. 1-4), illustrating the interest of such an evaluation in identifying where and how predictive rules can be improved. PMID:17193178

  14. Dietary ɛ-Polylysine Decreased Serum and Liver Lipid Contents by Enhancing Fecal Lipid Excretion Irrespective of Increased Hepatic Fatty Acid Biosynthesis-Related Enzymes Activities in Rats

    PubMed Central

    Hosomi, Ryota; Yamamoto, Daiki; Otsuka, Ren; Nishiyama, Toshimasa; Yoshida, Munehiro; Fukunaga, Kenji

    2015-01-01

    ɛ-Polylysine (EPL) is used as a natural preservative in food. However, few studies have been conducted to assess the beneficial functions of dietary EPL. The purpose of this study was to elucidate the mechanism underlying the inhibition of neutral and acidic sterol absorption and hepatic enzyme activity-related fatty acid biosynthesis following EPL intake. EPL digest prepared using an in vitro digestion model had lower lipase activity and micellar lipid solubility and higher bile acid binding capacity than casein digest. Male Wistar rats were fed an AIN-93G diet containing 1% (wt/wt) EPL or l-lysine. After 4 weeks of feeding these diets, the marked decrease in serum and liver triacylglycerol contents by the EPL diet was partly attributed to increased fecal fatty acid excretion. The activities of hepatic acetyl-coenzyme A carboxylase and glucose-6-phosphate dehydrogenase, which are key enzymes of fatty acid biosynthesis, were enhanced in rats fed EPL diet. The increased fatty acid biosynthesis activity due to dietary EPL may be prevented by the enhancement of fecal fatty acid excretion. The hypocholesterolemic effect of EPL was mediated by increased fecal neutral and acidic sterol excretions due to the EPL digest suppressing micellar lipid solubility and high bile acid binding capacity. These results show that dietary EPL has beneficial effects that could help prevent lifestyle-related diseases such as hyperlipidemia and atherosclerosis. PMID:25866749

  15. Experiment K304: Studies of specific hepatic enzymes and liver constituents involved in the conversion of carbohydrates to lipids in rats exposed to prolonged space flight

    NASA Technical Reports Server (NTRS)

    Abraham, S.; Klein, H. P.; Lin, C. Y.; Volkmann, C.; Tigranyan, R. A.; Vetrova, E. G.

    1981-01-01

    The effects of space flight on the activities of 26 enzymes concerned with carbohydrate and lipid metabolism in hepatic tissue taken from male Wistar rats are investigated. These activities were measured in the various hepatic cell compartments, i.e., cytosol, mitochondria and microsomes. In addition, the levels of glycogen, total lipids, phospholipids, triglycerides, cholesterol, cholesterol esters, and the fatty acid composition of the rat livers were also examined and quantified. A similar group of ground-based rats treated in an identical manner served as controls. Both flight and synchronous control rats were sacrificed at three time intervals: R+0, 7-11 hours after recovery; R+6, after 6 days; R+6(S), after 6 days (having undergone 2-5 hour periods of fixed stress in a "backupward" position on days 0, 3, 4, 5 and 6) and R+29, after 29 days post-flight. Although most of the enzyme activities and the amounts of liver constituents studied were unaffected by the period of weightlessness, some significant differences were observed.

  16. Dietary ɛ-Polylysine Decreased Serum and Liver Lipid Contents by Enhancing Fecal Lipid Excretion Irrespective of Increased Hepatic Fatty Acid Biosynthesis-Related Enzymes Activities in Rats.

    PubMed

    Hosomi, Ryota; Yamamoto, Daiki; Otsuka, Ren; Nishiyama, Toshimasa; Yoshida, Munehiro; Fukunaga, Kenji

    2015-03-01

    ɛ-Polylysine (EPL) is used as a natural preservative in food. However, few studies have been conducted to assess the beneficial functions of dietary EPL. The purpose of this study was to elucidate the mechanism underlying the inhibition of neutral and acidic sterol absorption and hepatic enzyme activity-related fatty acid biosynthesis following EPL intake. EPL digest prepared using an in vitro digestion model had lower lipase activity and micellar lipid solubility and higher bile acid binding capacity than casein digest. Male Wistar rats were fed an AIN-93G diet containing 1% (wt/wt) EPL or l-lysine. After 4 weeks of feeding these diets, the marked decrease in serum and liver triacylglycerol contents by the EPL diet was partly attributed to increased fecal fatty acid excretion. The activities of hepatic acetyl-coenzyme A carboxylase and glucose-6-phosphate dehydrogenase, which are key enzymes of fatty acid biosynthesis, were enhanced in rats fed EPL diet. The increased fatty acid biosynthesis activity due to dietary EPL may be prevented by the enhancement of fecal fatty acid excretion. The hypocholesterolemic effect of EPL was mediated by increased fecal neutral and acidic sterol excretions due to the EPL digest suppressing micellar lipid solubility and high bile acid binding capacity. These results show that dietary EPL has beneficial effects that could help prevent lifestyle-related diseases such as hyperlipidemia and atherosclerosis. PMID:25866749

  17. Effects of Fresh Yellow Onion Consumption on CEA, CA125 and Hepatic Enzymes in Breast Cancer Patients: A Double- Blind Randomized Controlled Clinical Trial.

    PubMed

    Jafarpour-Sadegh, Farnaz; Montazeri, Vahid; Adili, Ali; Esfehani, Ali; Rashidi, Mohammad-Reza; Mesgari, Mehran; Pirouzpanah, Saeed

    2015-01-01

    Onion (Allium cepa) consumption has been remarked in folk medicine which has not been noted to be administered so far as an adjunct to conventional doxorubicin-based chemotherapy in breast cancer patients. To our knowledge, this is the first study aimed to investigate the effects of consuming fresh yellow onions on hepatic enzymes and cancer specific antigens compared with a low-onion containing diet among breast cancer (BC) participants treated with doxorubicin. This parallel design randomized controlled clinical trial was conducted on 56 BC patients whose malignancy was confirmed with histopathological examination. Subjects were assigned in a stratified-random allocation into either group received body mass index dependent 100-160 g/d of onion as high onion group (HO; n=28) or 30-40 g/d small onion in low onion group (LO; n=28) for eight weeks intervention. Participants, care givers and laboratory assessor were blinded to the assignments (IRCT registry no: IRCT2012103111335N1). The compliance of participants in the analysis was appropriate (87.9%). Comparing changes throughout pre- and post-dose treatments indicated significant controls on carcinoembryonic antigen, cancer antigen-125 and alkaline phosphatase levels in the HO group (P<0.05). Our findings for the first time showed that regular onion administration could be effective for hepatic enzyme conveying adjuvant chemotherapy relevant toxicity and reducing the tumor markers in BC during doxorubicin-based chemotherapy. PMID:26625755

  18. Do drug metabolism and pharmacokinetic departments make any contribution to drug discovery?

    PubMed

    Smith, Dennis; Schmid, Esther; Jones, Barry

    2002-01-01

    The alignment of drug metabolism and pharmacokinetic departments with drug discovery has not produced a radical improvement in the pharmacokinetic properties of new chemical entities. The reason for this is complex, reflecting in part the difficulty of combining potency, selectivity, water solubility, metabolic stability and membrane permeability into a single molecule. This combination becomes increasingly problematic as the drug targets become more distant from aminergic seven-transmembrane-spanning receptors (7-TMs). The leads available for aminergic 7-TMs, like the natural agonists, are invariably small molecular weight, water soluble and potent. Even moving to 7-TMs for which the agonist is a peptide invariably produces lead matter that is less drug-like (higher molecular weight and lipophilic). The role of drug metabolism departments, therefore, has been to guide chemistry to obtaining adequate, rather than optimal, pharmacokinetic properties for these 'difficult' drug targets. A consistent belief of many researchers is that a high value is placed on optimal, rather than adequate, pharmacokinetic properties. One measure of value is market sales, and when these are examined no clear pattern emerges. Part of the success of amlodipine in the calcium channel antagonist sector must be due to its excellent pharmacokinetic profile, but the best-selling drugs among the angiotensin antagonists and beta-blockers have a much greater market share than other agents with better pharmacokinetic properties. Clearly, many other factors are important in the successful launch of a medicine, some reflected in the manner the compound is developed and the subsequent structure of the labelling. Overall, therefore the presence of drug metabolism in drug discovery has probably contributed most by allowing 'difficult' drug targets to be prosecuted, rather than by guiding medicinal chemists to optimal pharmacokinetics. These 'difficult' target candidates become successful drugs when

  19. Bioprinting of Micro-Organ Tissue Analog for Drug Metabolism Study

    NASA Astrophysics Data System (ADS)

    Sun, Wei

    An evolving application of tissue engineering is to develop in vitro 3D cell/tissue models for drug screening and pharmacological study. In order to test in space, these in vitro models are mostly manufactured through micro-fabrication techniques and incorporate living cells with MEMS or microfluidic devices. These cell-integrated microfluidic devices, or referred as microorgans, are effective in furnishing reliable and inexpensive drug metabolism and toxicity studies [1-3]. This paper will present an on-going research collaborated between Drexel University and NASA JSC Radiation Physics Laboratory for applying a direct cell printing technique to freeform fabrication of 3D liver tissue analog in drug metabolism study. The paper will discuss modeling, design, and solid freeform fabrication of micro-fluidic flow patterns and bioprinting of 3D micro-liver chamber that biomimics liver physiological microenvironment for enhanced drug metabolization. Technical details to address bioprinting of 3D liver tissue analog, integration with a microfluidic device, and basic drug metabolism study for NASA's interests will presented. 1. Holtorf H. Leslie J. Chang R, Nam J, Culbertson C, Sun W, Gonda S, "Development of a Three-Dimensional Tissue-on-a-Chip Micro-Organ Device for Pharmacokinetic Analysis", the 47th Annual Meeting of the American Society for Cell Biology, Washington, DC, December 1-5, 2007. 2. Chang, R., Nam, J., Culbertson C., Holtorf, H., Jeevarajan, A., Gonda, S. and Sun, W., "Bio-printing and Modeling of Flow Patterns for Cell Encapsulated 3D Liver Chambers For Pharmacokinetic Study", TERMIS North America 2007 Conference and Exposition, Westin Harbour Castle, Toronto, Canada, June 13-16, 2007. 3.Starly, B., Chang, R., Sun, W., Culbertson, C., Holtorf, H. and Gonda, S., "Bioprinted Tissue-on-chip Application for Pharmacokinetic Studies", Proceedings of World Congress on Tissue Engineering and Regenerative Medicine, Pittsburgh, PA, USA, April 24-27, 2006.

  20. Profiles in drug metabolism and toxicology: Richard Tecwyn Williams (1909-1979).

    PubMed

    Jones, Alan Wayne

    2015-01-01

    This article pays homage to the life and work of a veritable pioneer in toxicology and drug metabolism, namely a Welshman, Richard Tecwyn Williams, FRS. Professor Williams, or RT as he was known, made major contributions to knowledge about the metabolism and toxicology of drugs and xenobiotics during a scientific career spanning nearly 50 years. Author or coauthor of close to 400 research articles and reviews, including a classic book, entitled Detoxication Mechanisms, Williams and his research school investigated virtually all aspects of drug metabolism, especially conjugations. In particular, the concepts of phase 1 and phase II metabolic pathways were introduced by Williams; the biliary excretion of drugs was extensively studied as were species differences in drug metabolism and detoxication. Besides investigating the metabolism of many pharmaceutical drugs, such as sulfonamides and thalidomide, Williams and his group investigated the disposition and fate in the body of organic pesticides and recreational drugs of abuse, such as amphetamine, methamphetamine and lysergic acid diethylamide (LSD). PMID:26610047

  1. The 2014 Bernard B. Brodie award lecture-epoxide hydrolases: drug metabolism to therapeutics for chronic pain.

    PubMed

    Kodani, Sean D; Hammock, Bruce D

    2015-05-01

    Dr. Bernard Brodie's legacy is built on fundamental discoveries in pharmacology and drug metabolism that were then translated to the clinic to improve patient care. Similarly, the development of a novel class of therapeutics termed the soluble epoxide hydrolase (sEH) inhibitors was originally spurred by fundamental research exploring the biochemistry and physiology of the sEH. Here, we present an overview of the history and current state of research on epoxide hydrolases, specifically focusing on sEHs. In doing so, we start with the translational project studying the metabolism of the insect juvenile hormone mimic R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene], which led to the identification of the mammalian sEH. Further investigation of this enzyme and its substrates, including the epoxyeicosatrienoic acids, led to insight into mechanisms of inflammation, chronic and neuropathic pain, angiogenesis, and other physiologic processes. This basic knowledge in turn led to the development of potent inhibitors of the sEH that are promising therapeutics for pain, hypertension, chronic obstructive pulmonary disorder, arthritis, and other disorders. PMID:25762541

  2. The 2014 Bernard B. Brodie Award Lecture—Epoxide Hydrolases: Drug Metabolism to Therapeutics for Chronic Pain

    PubMed Central

    Kodani, Sean D.

    2015-01-01

    Dr. Bernard Brodie’s legacy is built on fundamental discoveries in pharmacology and drug metabolism that were then translated to the clinic to improve patient care. Similarly, the development of a novel class of therapeutics termed the soluble epoxide hydrolase (sEH) inhibitors was originally spurred by fundamental research exploring the biochemistry and physiology of the sEH. Here, we present an overview of the history and current state of research on epoxide hydrolases, specifically focusing on sEHs. In doing so, we start with the translational project studying the metabolism of the insect juvenile hormone mimic R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene], which led to the identification of the mammalian sEH. Further investigation of this enzyme and its substrates, including the epoxyeicosatrienoic acids, led to insight into mechanisms of inflammation, chronic and neuropathic pain, angiogenesis, and other physiologic processes. This basic knowledge in turn led to the development of potent inhibitors of the sEH that are promising therapeutics for pain, hypertension, chronic obstructive pulmonary disorder, arthritis, and other disorders. PMID:25762541

  3. Unequal prognostic potentials of p53 gain-of-function mutations in human cancers associate with drug-metabolizing activity.

    PubMed

    Xu, J; Wang, J; Hu, Y; Qian, J; Xu, B; Chen, H; Zou, W; Fang, J-Y

    2014-01-01

    Mutation of p53 is the most common genetic change in human cancer, causing complex effects including not only loss of wild-type function but also gain of novel oncogenic functions (GOF). It is increasingly likely that p53-hotspot mutations may confer different types and magnitudes of GOF, but the evidences are mainly supported by cellular and transgenic animal models. Here we combine large-scale cancer genomic data to characterize the prognostic significance of different p53 mutations in human cancers. Unexpectedly, only mutations on the Arg248 and Arg282 positions displayed significant association with shorter patient survival, but such association was not evident for other hotspot GOF mutations. Gene set enrichment analysis on these mutations revealed higher activity of drug-metabolizing enzymes, including the CYP3A4 cytochrome P450. Ectopic expression of p53 mutant R282W in H1299 and SaOS2 cells significantly upregulated CYP3A4 mRNA and protein levels, and cancer cell lines bearing mortality-associated p53 mutations display higher CYP3A4 expression and resistance to several CYP3A4-metabolized chemotherapeutic drugs. Our results suggest that p53 mutations have unequal GOF activities in human cancers, and future evaluation of p53 as a cancer biomarker should consider which mutation is present in the tumor, rather than having comparison between wild-type and mutant genotypes. PMID:24603336

  4. Understanding the determinants of selectivity in drug metabolism through modeling of dextromethorphan oxidation by cytochrome P450

    PubMed Central

    Oláh, Julianna; Mulholland, Adrian J.; Harvey, Jeremy N.

    2011-01-01

    Cytochrome P450 enzymes play key roles in the metabolism of the majority of drugs. Improved models for prediction of likely metabolites will contribute to drug development. In this work, two possible metabolic routes (aromatic carbon oxidation and O-demethylation) of dextromethorphan are compared using molecular dynamics (MD) simulations and density functional theory (DFT). The DFT results on a small active site model suggest that both reactions might occur competitively. Docking and MD studies of dextromethorphan in the active site of P450 2D6 show that the dextromethorphan is located close to heme oxygen in a geometry apparently consistent with competitive metabolism. In contrast, calculations of the reaction path in a large protein model [using a hybrid quantum mechanical–molecular mechanics (QM/MM) method] show a very strong preference for O-demethylation, in accordance with experimental results. The aromatic carbon oxidation reaction is predicted to have a high activation energy, due to the active site preventing formation of a favorable transition-state structure. Hence, the QM/MM calculations demonstrate a crucial role of many active site residues in determining reactivity of dextromethorphan in P450 2D6. Beyond substrate binding orientation and reactivity of Compound I, successful metabolite predictions must take into account the detailed mechanism of oxidation in the protein. These results demonstrate the potential of QM/MM methods to investigate specificity in drug metabolism. PMID:21444768

  5. Pharmacokinetics, Efficacy, and Safety of Hepatitis C Virus Drugs in Patients with Liver and/or Renal Impairment.

    PubMed

    Smolders, Elise J; de Kanter, Clara T M M; van Hoek, Bart; Arends, Joop E; Drenth, Joost P H; Burger, David M

    2016-07-01

    Hepatitis C virus (HCV)-infected patients often suffer from liver cirrhosis, which can be complicated by renal impairment. Therefore, in this review we describe the treatment possibilities in HCV patients with hepatic and renal impairment. Cirrhosis alters the structure of the liver, which affects drug-metabolizing enzymes and drug transporters. These modifications influence the plasma concentration of substrates of drugs metabolized/transported by these enzymes. The direct-acting antivirals (DAAs) are substrates of, for example, cytochrome P450 enzymes in the liver. Most DAAs are not studied in HCV-infected individuals with decompensated cirrhosis, and therefore awareness is needed when these patients are treated. Most DAAs are contraindicated in cirrhotic patients; however, patients with a Child-Pugh score of B or C can be treated safely with a normal dose sofosbuvir plus ledipasvir or daclatasvir, in combination with ribavirin. Patients with renal impairment (glomerular filtration rate [GFR] <90 mL/min) or who are dependent on dialysis often tolerate ribavirin treatment poorly, even after dose adjustments. However, most DAAs can be used at the normal dose because DAAs are not renally excreted. To date, grazoprevir plus elbasvir is the preferred DAA regimen in patients with renal impairment as data are pending for sofosbuvir patients with GFR <30 mL/min (as for ledipasvir and velpatasvir). However, sofosbuvir has been used in a small number of patients with severe renal impairment and, based on these trials, we recommend sofosbuvir 400 mg every day when no other DAA regimen is available. Ledipasvir and velpatasvir are not recommended in patients with severe renal impairment. PMID:27098247

  6. Chronic alcohol intake up-regulates hepatic expressions of carotenoid cleavage enzymes and peroxisomal proliferator-activated receptors in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive and chronic alcohol intake leads to a lower hepatic vitamin A status by interfering with vitamin A metabolism.Dietary provitamin A carotenoids can be converted into vitamin A mainly by carotenoid 15,15’-monooxygenase 1 (CMO1) and, to a lesser degree, carotenoid 9910’-monooxygenase 2 (CMO2)...

  7. Nonlinear (amplified) relationship between nuclear occupancy by triiodothyronine and the appearance rate of hepatic alpha-glycerophosphate dehydrogenase and malic enzyme in the rat.

    PubMed Central

    Oppenheimer, J H; Coulombe, P; Schwartz, H L; Gutfeld, N W

    1978-01-01

    Three separate approaches were applied to examine the general relationship between R, the rate of induction of specific enzymes (mitochondrial alpha-glycero-phosphate dehydrogenase and cytosolic malic enzyme) and q, the fractional nuclear occupancy by triiodothyronine in male Sprague-Dawley rats. Daily 200-microgram injections of triiodothyronine per 10u g body wt for 7 days resulted in saturation of the hepatic nuclear sites and the achievement of an apparent new steady state of enzyme levels. The increase achieved over base-line hypothyroid levels was then compared with the increment over hypothyroid base line characteristic of intact euthyroid animals with 47% of nuclear sites occupied. The maximal theoretical reate of steady-state enzyme induction could be protected on the basis of the observed maximal increase in enzyme activity observed 1 day after the injection of graded doses of hormone and lambda, the known fractional rate of enzyme dissipation. The 24-h dose-response studies were used to generate R as a continuous function of q, both in hypothyroid as well as in euthyroid animals. This approach involved the numerical solution of an ordinary differential equation describing the rate of change of enzyme as a function of R, which was assumed to be uniquely related to q. Results of these analyses indicated that the ratio of the maximal rate of induction of enzyme at full occupancy to the rate of induction under euthyroid conditions assumes a value between 9.0 and 19.5, depending on the precise analytic and experimental approach applied. This value is far in excess of the theoretical ratio 2.13 which on would anticipate if R were linearly related to q and 47% of the nuclear sites occupied under physiological conditions. Thus, the signal for enzyme induction appears to undergo progressjive amplification with increasing nuclear occupancy. Moreover, the curve describing the relationship between R and q appears highly nonlinear throughout (concave upwards

  8. Effect of chronic ethanol (EtOH) and aging on drug metabolism in F-344 male rats

    SciTech Connect

    Galinsky, R.E.; Johnson, D.H.; Kimura, R.E.; Franklin, M.R. )

    1989-02-09

    The effects of chronic ethanol on in vitro and in vivo drug metabolism were examined in 6 and 25 month old male Fischer 344 rats. Animals were divided into three diet groups: (1) Diet containing EtOH, (2) pair-fed controls and (3) rat chow ad lib. Rats in groups 1 and 2 were fed 3 times daily for six weeks via permanent gastrostomy and received EtOH at doses of 5-8 g/kg/day in the first 3 weeks and 12 g/kg/day for the last 3 weeks. Total caloric intake was 90-120 kcal/kg/day. After 6 weeks, the pharmacokinetics of i.v. acetaminophen (A), 30 mg/kg, were examined to probe in vivo drug conjugation. There was no effects of EtOH on the total CL of A in young or old rats. The fraction of the dose recovered in the urine as A-glucuronide and the partial clearance to A-glucuronide was increased by EtOH. There was no effect on the rate of A-sulfate formation. EtOH increased the renal clearance of A but not of A-sulfate or A-glucuronide. In vitro, EtOH increased hepatic cytochrome P-450 concentration and p-nitroanisole demethylase activity, especially in old rats where values returned to those seen in untreated young males. Erythromycin and ethylmorphine demethylase and p-nitrophenol hydroxylase activities were not increased by the EtOH treatment. EtOH increased UDP-glucuronosyltransferase activity towards 1-naphthol, but not towards morphine, estrone, or testosterone. EtOH had no effect on the cytosolic glutathione S-transferase (1-chloro-2,4-dinitrobenzene) and phenol sulfotransferase (p-nitrophenol) activities.

  9. Effect of Commiphora mukul gum resin on hepatic marker enzymes, lipid peroxidation and antioxidants status in pancreas and heart of streptozotocin induced diabetic rats

    PubMed Central

    Ramesh, B; Karuna, R; Sreenivasa, Reddy S; Haritha, K; Sai, Mangala D; Sasi, Bhusana Rao B; Saralakumari, D

    2012-01-01

    Objective To study the antioxidant efficacy of Commiphora mukul (C. mukul) gum resin ethanolic extract in streptozotocin (STZ) induced diabetic rats. Methods The male Wistar albino rats were randomly divided into four groups of eight animals each: Control group (C), CM-treated control group (C+CMEE), Diabetic control group (D), CM- treated diabetic group (D+CMEE). Diabetes was induced by intraperitoneal injection of STZ (55 mg/kg/ bwt). After being confirmed the diabetic rats were treated with C. mukul gum resin ethanolic extract (CMEE) for 60 days. The biochemical estimations like antioxidant, oxidative stress marker enzymes and hepatic marker enzymes of tissues were performed. Results The diabetic rats showed increased level of enzymatic activities aspartate aminotransaminase (AST), alanine aminotransaminase (ALT) in liver and kidney and oxidative markers like lipid peroxidation (LPO) and protein oxidation (PO) in pancreas and heart. Antioxidant enzyme activities were significantly decreased in the pancreas and heart compared to control group. Administration of CMEE (200 mg/kg bw) to diabetic rats for 60 days significantly reversed the above parameters towards normalcy. Conclusions In conclusion, our data indicate the preventive role of C. mukul against STZ-induced diabetic oxidative stress; hence this plant could be used as an adjuvant therapy for the prevention and/or management of diabetes and aggravated antioxidant status. PMID:23569867

  10. Effects of dietary tannic acid on the growth, hepatic gene expression, and antioxidant enzyme activity in Brandt's voles (Microtus brandti).

    PubMed

    Ye, Man-Hong; Nan, Yan-Lei; Ding, Meng-Meng; Hu, Jun-Bang; Liu, Qian; Wei, Wan-Hong; Yang, Sheng-Mei

    2016-01-01

    This study was designed to investigate the physiological and biochemical responses of Brandt's voles to the persistent presence of dietary tannic acid. The diet for animals in the experimental group was supplemented with 3% dietary tannic acid for 5weeks. The control group received a commercial lab chow. No significant differences were detected in body weight, organ (heart, kidney, and liver) weights, and organ parameters between animals from two groups. However, voles in the experimental group had significantly higher daily food intake, increased contents of proline and histidine in saliva and feces after protein hydrolysis, and elevated hepatic expression of transferrin than the control. Our results suggested the existence of adaptive strategies developed in Brandt's voles to overcome the adverse effects of dietary tannic acid. (1) Food consumption was increased to satisfy their nutritional demands. (2) The secretion of tannic-acid-binding salivary proteins was promoted. (3) The absorption of iron was enhanced. These alterations contributed to neutralize the negative effects of tannic acid and maintain body mass in animals supplemented with tannic acid. As the result of the consumption of tannic acid, hepatic expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly decreased, while the overall potential of the antioxidant system, characterized by increased hepatic enzymatic activities of catalase and glutathione peroxidase, was enhanced. Our results also implied the involvement of tannic acid in the regulation of lipid metabolism and oxidative stress in voles. PMID:26850644

  11. Downregulation of Mouse Hepatic CYP3A Protein by 3-Methylcholanthrene Does Not Require Cytochrome P450-Dependent Metabolism

    PubMed Central

    Lee, Chunja; Ding, Xinxin

    2013-01-01

    The aryl hydrocarbon receptor (AHR)–dependent induction of cytochromes P450 (P450) such as CYP1A1 by 3-methylcholanthrene (MC) and related polycyclic aromatic hydrocarbons is well characterized. We reported previously that MC treatment triggers a pronounced downregulation, particularly at the protein level, of mouse hepatic Cyp3a11, a counterpart of the key human drug-metabolizing enzyme CYP3A4. To determine whether this effect of MC requires hepatic microsomal P450 activity, we studied liver Cpr-null (LCN) mice with hepatocyte-specific conditional deletion of the NADPH-cytochrome P450 oxidoreductase gene. In vehicle-treated animals, basal levels of CYP3A11 mRNA and CYP3A protein immunoreactivity were elevated by approximately 9-fold in LCN mice compared with wild-type (WT) mice, whereas CYP3A catalytic activity was profoundly compromised in LCN mice. MC treatment caused suppression of CYP3A11 mRNA, CYP3A protein immunoreactivity, and CYP3A catalytic activity in WT mice, and the MC effects at the mRNA and protein levels were maintained in LCN mice. Flavin-containing monooxygenase-3 (Fmo3) induction by MC was suggested previously to occur via an AHR-dependent mechanism requiring conversion of the parent compound to DNA-damaging reactive metabolites; however, hepatic FMO3 mRNA levels were dramatically increased by MC in both WT and LCN mice. MC did not function as a mechanism-based inactivator of CYP3A enzymes in hepatic microsomes prepared from untreated WT mice, under conditions in which 1-aminobenzotriazole caused marked NADPH-dependent loss of total P450 content and CYP3A catalytic activity. These results indicate that MC downregulates mouse hepatic CYP3A protein via a pretranslational mechanism that does not require hepatic microsomal P450-dependent activity. PMID:23846873

  12. [Activity of the sphingomyelin cycle enzymes and concentration of products of sphingomyelin degradation in the rat liver in the course of acute toxic hepatitis].

    PubMed

    Serebrov, V Iu; Kuz'menko, D I; Burov, P G; Sapugol'tseva, O B

    2010-01-01

    Activity of key enzymes of a sphingomyelin cycle and the maintenance of its components (sphingomyelin, ceramide and sphingosine-1-phosphate) have been studied in livers of rats in dynamics of the acute toxic hepatitis caused by hypodermic introduction of an oil solution of CCl4. Sphingomyelinase activity significally increased already on early terms and remained increased over the whole period of observation. Activity of ceramidase insignificantly differed from the control level. The levels of sphingomyelin and sphingosine-1-phosphate did not undergo marked changes while ceramide content significally increased. Thus, balance between liver content of ceramide (proapoptotic) and the sphingosine-1-phosphate, being the antiapoptotic factor, was shifted towards ceramide. In sphingomyelin molecules there was a significant decrease in the content of fatty acids C18: and C22:2, while in ceramide molecules and sphingosine-1-phosphate only fatty acid C22:2 changed. In spite of significant decrease in content of some unsaturated fatty acids, calculated unsaturation coefficients of the fatty acid component of the sphingomyelin cycle metabolites. Thus, our results together with literature data suggests involvement of ceramide-mediated apoptosis in the pathogenesis of acute toxic hepatitis. Elimination of damaged hepatocytes facilitates realization of repair processes and optimization of cellular community of a liver. PMID:21341516

  13. A method for the determination of the hepatic enzyme activity catalyzing bile acid acyl glucuronide formation by high-performance liquid chromatography with pulsed amperometric detection.

    PubMed

    Ikegawa, S; Oohashi, J; Murao, N; Goto, J

    2000-05-01

    A method for the determination of the activity of hepatic glucuronyltransferase catalyzing formation of bile acid 24-glucuronides using high-performance liquid chromatography (HPLC) with pulsed amperometric detection (PAD) has been developed. Bile acid 24-glucuronides were simultaneously separated on a semimicrobore column, Capcell Pak C18UG120, using 20 mM ammonium phosphate (pH 6.0)-acetonitrile (27:10 and 16:10) as the mobile phase in the stepwise gradient elution mode. A 1 M potassium hydroxide solution for the hydrolysis of the 24-glucuronides, which liberates the corresponding bile acids and glucuronic acid, was mixed with the mobile phase in a post-column mode, and the resulting eluant was heated at 90 degrees C, the 24-glucuronides being monitored using a pulsed amperometric detector; the limit of detection was 10 ng. The proposed method was applied to the determination of the hepatic enzyme activity catalyzing bile acid 24-glucuronide formation and the result exhibited the efficient 24-glucuronide formation of the monohydroxylated bile acid, lithocholic acid. PMID:10850616

  14. Development of stably transfected human and rat hepatoma cell lines for the species-specific assessment of xenobiotic response enhancer module (XREM)-dependent induction of drug metabolism.

    PubMed

    Fery, Yvonne; Mueller, Stefan O; Schrenk, Dieter

    2010-11-01

    Based on our current knowledge, PXR holds a key position in the induction of a selective battery of enzymes and transporters of drug metabolism. In order to prevent serious adverse drug effects or unpredicted drug-drug interactions (DDI), it is compulsory to investigate the possible inducing potency of drugs under development. Furthermore, analysis of the inducing potency of environmental pollutants and new or manufactured chemicals is part of toxicological risk assessment. In non-transfected human HepG2 and rat H4IIE hepatoma cells, we examined the characteristics of expression of 45 genes involved in drug metabolism. A few gene products such as CYP2B6 or CYP3A4 mRNA were prominent in HepG2 cells while their major rat counterparts were, e.g., CYP2B3 or CYP3A1/3A3. Furthermore, a number of xenobiotic receptors including PXR were expressed in both cell lines. A number of genes were regulated in a cell type and species-specific manner after incubation with the prototypical PXR agonists rifampicin or dexamethasone, respectively. Then, we established cell-based reporter gene assays for screening for PXR-dependent induction of drug metabolism. HepG2 and H4IIE cells were stably transfected with a reporter gene containing PXR responsive elements (XREMs) which mediate the induction of PXR target genes such as CYP3A enzymes. With both stable cell lines the CYP inducers clotrimazole, dexamethasone, omeprazole, phenobarbital, rifampicin, as well as the drug candidate EMD 392949 and the brominated flame retardants hexabromocylododecane (HBCD) and a pentabromodiphenyl ether (pentaBDE) mixture were screened. In the human HepG2-XREM3 and rat H4IIE-XREM3 cells, clotrimazole and HBCD were found as common activators of the human and rat PXR whereas pentaBDE was more effective with the human cell system. Omeprazole and phenobarbital did not induce the rat PXR-dependent reporter gene expression in H4IIE-XREM3 cells, while a moderate increase was found in HepG2-XREM3 cells. EMD 392949

  15. Effects of selenium dietary enhancement on hatchery-reared coho salmon, Oncorhynchus kisutch (Walbaum), when compared with wild coho: hepatic enzymes and seawater adaptation evaluated.

    USGS Publications Warehouse

    Felton, S.P.; Landolt, M.L.; Grace, R.; Palmisano, A.N.

    1996-01-01

    Hatchery-reared coho salmon, Oncorhynchus kisutch (Walbaum), were fed elevated levels of selenium (as Na2SeO3) to raise eviscerated body burdens to the level measured in wild counterparts. The goal was to find a dietary concentration that would achieve the desired effect without causing damage to growth and normal development. To measure some indices of health, the detoxifying enzymes chosen were hepatic glutathione peroxidase (GSH-Px) and hepatic superoxide dismutase (SOD). Eviscerated body selenium (Se) concentration, GSH-Px and SOD levels were measured during and at the end of the 9 month freshwater feeding trial. Selenium retention and enzyme activity were also measured during 6 months’residence in sea water (SW). Selenium supplements were added to a commercial ration to give final concentrations of 1.1, 8.6, 11.1, 13.6 μg g-1 Se in the four respective diets. The results indicated that a dietary concentration of 8.6 μg g-1selenium was capable of inducing eviscerated body burdens similar to those found in wild fish. The elevated selenium levels persisted throughout the freshwater (FW) rearing phase, but declined when the fish were fed an unsupplemented ration upon SW entry. Superoxide dismutase levels did not increase above control levels. Glutathione peroxidase levels increased in fish fed the supplemented diets. GSH-Px activity declined in the higher supplemented dietary groups when all groups were reduced to the control group level of 1.1 μg g-1. Cumulative mortality in SW was 20% in fish fed either the 1.1 or the 8.6 μg g-1 Se diets. The 8.6 μg g-1 Se supplemented diets did produce healthy coho, comparable to their wild counterparts.

  16. PNPLA3 148M Carriers with Inflammatory Bowel Diseases Have Higher Susceptibility to Hepatic Steatosis and Higher Liver Enzymes

    PubMed Central

    Mancina, Rosellina Margherita; Spagnuolo, Rocco; Milano, Marta; Brogneri, Simona; Morrone, Attilio; Cosco, Cristina; Lazzaro, Veronica; Russo, Cristina; Ferro, Yvelise; Pingitore, Piero; Pujia, Arturo; Montalcini, Tiziana; Doldo, Patrizia; Garieri, Pietro; Piodi, Luca; Caprioli, Flavio; Valenti, Luca

    2015-01-01

    Background: Inflammatory bowel diseases (IBD) are characterized by chronic relapsing inflammation of the gastrointestinal tract and encompass Crohn's disease and ulcerative colitis. IBD are often associated with extraintestinal manifestations affecting multiple organs including the liver. Increased levels of serum aminotransferases, possibly related to nonalcoholic fatty liver disease, constitute one of the most frequently described IBD-related liver diseases. The PNPLA3 I148M substitution is a major common genetic determinant of hepatic fat content and progression to chronic liver disease. The aim of this study was to investigate whether carriers of PNPLA3 148M allele with IBD have higher risk of liver steatosis and increase in transaminases levels. Methods: The PNPLA3 I148M (rs738409) genotype was performed by Taqman assays in 158 individuals from Southern Italy (namely, Catanzaro cohort) and in 207 individuals from Northern Italy (namely, Milan cohort) with a definite diagnosis of IBD. Demographic and clinical data and also alanine transaminase levels were collected for both cohorts. The Catanzaro cohort underwent liver evaluation by sonography and liver stiffness and controlled attenuation parameter measurements by transient elastography. Results: Here, we show for the first time that carriers of the PNPLA3 148M allele with IBD have a greater risk of hepatic steatosis (odds ratio, 2.9, and confidence interval, 1.1–7.8), higher controlled attenuation parameter values (P = 0.029), and increased circulating alanine transaminase (P = 0.035) in the Catanzaro cohort. We further confirm the higher alanine transaminase levels in the Milan cohort (P < 0.001). Conclusions: Our results show that PNPLA3 148M carriers with IBD have higher susceptibility to hepatic steatosis and liver damage. PMID:26355465

  17. Inhibition of hepatic cytochrome P450 enzymes and sodium/bile acid cotransporter exacerbates leflunomide-induced hepatotoxicity

    PubMed Central

    Ma, Lei-lei; Wu, Zhi-tao; Wang, Le; Zhang, Xue-feng; Wang, Jing; Chen, Chen; Ni, Xuan; Lin, Yun-fei; Cao, Yi-yi; Luan, Yang; Pan, Guo-yu

    2016-01-01

    Aim: Leflunomide is an immunosuppressive agent marketed as a disease-modifying antirheumatic drug. But it causes severe side effects, including fatal hepatitis and liver failure. In this study we investigated the contributions of hepatic metabolism and transport of leflunomide and its major metabolite teriflunomide to leflunomide induced hepatotoxicity in vitro and in vivo. Methods: The metabolism and toxicity of leflunomide and teriflunomide were evaluated in primary rat hepatocytes in vitro. Hepatic cytochrome P450 reductase null (HRN) mice were used to examine the PK profiling and hepatotoxicity of leflunomide in vivo. The expression and function of sodium/bile acid cotransporter (NTCP) were assessed in rat and human hepatocytes and NTCP-transfected HEK293 cells. After Male Sprague-Dawley (SD) rats were administered teriflunomide (1,6, 12 mg·kg−1·d−1, ig) for 4 weeks, their blood samples were analyzed. Results: A nonspecific CYPs inhibitor aminobenzotriazole (ABT, 1 mmol/L) decreased the IC50 value of leflunomide in rat hepatocytes from 409 to 216 μmol/L, whereas another nonspecific CYPs inhibitor proadifen (SKF, 30 μmol/L) increased the cellular accumulation of leflunomide to 3.68-fold at 4 h. After oral dosing (15 mg/kg), the plasma exposure (AUC0-t) of leflunomide increased to 3-fold in HRN mice compared with wild type mice. Administration of leflunomide (25 mg·kg−1·d−1) for 7 d significantly increased serum ALT and AST levels in HRN mice; when the dose was increased to 50 mg·kg−1·d−1, all HRN mice died on d 6. Teriflunomide significantly decreased the expression of NTCP in human hepatocytes, as well as the function of NTCP in rat hepatocytes and NTCP-transfected HEK293 cells. Four-week administration of teriflunomide significantly increased serum total bilirubin and direct bilirubin levels in female rats, but not in male rats. Conclusion: Hepatic CYPs play a critical role in detoxification process of leflunomide, whereas the major

  18. E2 potentializes benzo(a)pyrene-induced hepatic cytochrome P450 enzyme activities in Nile tilapia at high concentrations.

    PubMed

    Rodrigues, Aline Cristina Ferreira; Moneró, Tatiana de Oliveira; Frighetto, Rosa Toyoko Shiraishi; de Almeida, Eduardo Alves

    2015-11-01

    In the aquatic environment, biotransformation enzymes are established biomarkers for assessing PAH exposure in fish, but little is known about the effect of 17β-estradiol (E2) on these enzymes during exposure to benzo(a)pyrene (BaP). In this study, Nile tilapia (Oreochromis niloticus) were exposed for 3, 5, and 10 days to BaP (300 μg L(-1)) and E2 (5 μg L(-1)). These substances were applied isolated or mixed. In the mixture experiment, fish were analyzed pre- and postexposure in order to better understand whether preexposure to the hormone masks the responses activated by PAH or vice versa. Phase I enzymes ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-depenthylase (PROD), and benzyloxyresorufin-O-debenzylase (BROD) activities as well as the phase II enzyme glutathione S-transferase (GST) were analyzed. Isolated E2 treatment decreased EROD activity after 3 days, but this enzyme activity returned to control values after 5 and 10 days of exposure. Isolated BaP treatment significantly induced EROD activity after 3 and 5 days, and the activity returned to control levels after ten exposure days. Combined treatment (E2 + Bap) significantly increased EROD activity, both in the pre- and postexposure. This increase was even higher than in the isolated BaP treatment, suggesting a synergism between these two compounds. When E2 and BaP were used singly, they did not change BROD and PROD activities. However, combined treatment (E2 + Bap) significantly increased PROD activity. Isolated BaP treatment increased GST activity after 10 days. However, this response was not observed in the mixture treatment, suggesting that E2 suppressed the GST induction modulated by BaP. The results put together indicated that E2 altered the biotransformation pathway regarding enzymes activated by BaP in Nile tilapia. PMID:25280508

  19. Quercetin induces hepatic γ-glutamyl hydrolase expression in rats by suppressing hepatic microRNA rno-miR-125b-3p.

    PubMed

    Wein, Silvia Anette; Laviano, Alessandro; Wolffram, Siegfried

    2015-12-01

    Exogenous factors such as food components including the flavonoid quercetin are suspected to influence micro RNA (miRNA) concentrations and thus possibly target enzymes involved in xenobiotic metabolism. This study therefore investigates the influence of orally administered quercetin on hepatic miRNA and the identification of enzyme target mRNAs relevant in drug metabolism. Male Wistar rats (n=16) were fed either a diet without (C) or with (Q) the addition of 100-ppm quercetin for 7 weeks and subsequently euthanized at the end of the dark phase. To avoid strong effects of food deprivation on hepatic metabolism, food was not removed until 5 h prior to the procedure. Liver was immediately dissected and snap-frozen in liquid nitrogen. Concentrations of 352 hepatic miRNA were measured in pool samples of each dietary group (n=8) using the RT(2) miRNA PCR Array System. Differential expression of miRNAs was assumed with fold changes ≥3. Target genes of differentially expressed miRNAs were identified using the database TargetScan. Because rno-miR-125b-3p showed the most prominent fold-change (-9) we further analyzed the expression of its top predicted target gene gamma-glutamyl hydrolase (GGH) by quantitative real-time PCR using hypoxanthine phosphoribosyltransferase 1 (hprt1) as endogenous control. Compared to controls, 23 miRNAs were differentially expressed in rats fed quercetin. A ninefold reduction in hepatic miRNA rno-miR-125b-3p was paralleled by significant induction of GGH mRNA in liver of quercetin fed rats. Because increased GGH expressions were repeatedly associated with resistance to methotrexate, concomitant intake with quercetin should be monitored carefully. PMID:26432773

  20. Effects of cigarette smoke and dietary vitamin E levels on selected lung and hepatic biotransformation enzymes in mice

    SciTech Connect

    Graziano, M.J.; Gairola, C.; Dorough, H.W.

    1985-01-01

    Young male C57BL mice were exposed nose-only to cigarette smoke 20 min/day for 8 weeks while maintained on diets containing 0, 5, and 100 ppm of vitamin E. Smoking had no effect on hepatic aryl hydrocarbon hydroxylase (AHH), UDP-glucuronyltransferase, glutathione S-transferase, parathion desulfurase, or parathion esterase activity. Lung AHH activity was increased in all smoke-exposed mice, although the increase was significantly less in animals maintained on the vitamin E-free diet. All mice on the vitamin E-free diet showed reduced lung AHH activity and increased hepatic lipid peroxidation. No other biotransformations tested were significantly altered by varying vitamin E concentrations alone or in combination with cigarette smoke. For all vitamin E diets, both the smoke-exposed and sham-treated mice gained significantly less weight than the control animals. This effect was attributed to stress induced by restraint of the animals within the smoking apparatus. The results of these experiments show that both cigarette smoke and vitamin E-deficient diets may affect xenobiotic metabolism but that the combination does not appear to alter markedly their individual effects or to induce ones not previously observed.

  1. Chronic Kidney Disease Alters Vitamin A Homeostasis via Effects on Hepatic RBP4 Protein Expression and Metabolic Enzymes.

    PubMed

    Jing, J; Isoherranen, N; Robinson-Cohen, C; Petrie, I; Kestenbaum, B R; Yeung, C K

    2016-08-01

    Vitamin A, via retinoic acid (RA), is a critical micronutrient. Normally, plasma concentrations are tightly regulated. Concentrations of vitamin A metabolites (13cis-RA, atRA) and relationships between RBP4 and retinoids have never been fully evaluated in adult patients with CKD. We measured retinoid and RBP4 concentrations in plasma and urine from 55 adult patients with CKD and 21 matched healthy subjects. RBP4 and retinol levels were increased approximately twofold in patients with CKD, with a negative correlation between plasma retinol and eGFR (p = 0.006) and plasma RBP4 and eGFR (p = 0.0007). RBP4 renal clearance was higher in patients with CKD than healthy subjects but not associated with eGFR. Circulating concentrations of atRA increased and concentrations of 13cis-RA decreased in subjects with CKD with no change in RA-to-retinol ratio. Increases in circulating retinol, RBP4, and atRA may be due to increased hepatic RBP4 synthesis, retinyl ester hydrolysis, and/or hepatic secretion of RBP4-retinol. PMID:27277845

  2. Chokeberry (Aronia melanocarpa) juice modulates 7,12-dimethylbenz[a]anthracene induced hepatic but not mammary gland phase I and II enzymes in female rats.

    PubMed

    Szaefer, Hanna; Krajka-Kuźniak, Violetta; Ignatowicz, Ewa; Adamska, Teresa; Baer-Dubowska, Wanda

    2011-03-01

    Chokeberry is a rich source of procyanidins known to have several types of biological activity including anticarcinogenic potential in experimental models. In this study we examined the effect of chokeberry juice on the hepatic and mammary gland carcinogen metabolizing enzyme expression altered by the polycyclic aromatic hydrocarbon, 7,12-dimethylbenz[a]anthracene (DMBA). Sprague-Dawley rats were gavaged with chokeberry juice (8 ml/kg b.w.) for 28 consecutive days. DMBA was administered i.p. on the 27th and the 28th days. Pretreatment with chokeberry juice reduced the activity of CYP1A1 and increased that of CYP2B involved in metabolic activation/detoxication of DMBA in rat liver, as well as expression and activity of phase II enzymes. Chokeberry juice had no effect on these parameters in the mammary gland and DMBA induced DNA damage in rat blood cells. These results together with our earlier observations indicate that metabolic alterations induced by chokeberry feeding are tissue specific and depend on the class of carcinogen. PMID:21787703

  3. A competitive enzyme-linked immunosorbent assay specific for murine hepcidin-1: correlation with hepatic mRNA expression in established and novel models of dysregulated iron homeostasis

    PubMed Central

    Gutschow, Patrick; Schmidt, Paul J.; Han, Huiling; Ostland, Vaughn; Bartnikas, Thomas B.; Pettiglio, Michael A.; Herrera, Carolina; Butler, James S.; Nemeth, Elizabeta; Ganz, Tomas; Fleming, Mark D.; Westerman, Mark

    2015-01-01

    Mice have been essential for distinguishing the role of hepcidin in iron homeostasis. Currently, investigators monitor levels of murine hepatic hepcidin-1 mRNA as a surrogate marker for the bioactive hepcidin protein itself. Here, we describe and validate a competitive, enzyme-linked immunosorbent assay that quantifies hepcidin-1 in mouse serum and urine. The assay exhibits a biologically relevant lower limit of detection, high precision, and excellent linearity and recovery. We also demonstrate correlation between serum and urine hepcidin-1 values and validate the competitive enzyme-linked immunosorbent assay by analyzing plasma hepcidin response of mice to physiological challenges, including iron deficiency, iron overload, acute blood loss, and inflammation. Furthermore, we analyze multiple murine genetic models of iron dysregulation, including β-thalassemia intermedia (Hbbth3/+), hereditary hemochromatosis (Hfe−/−, Hjv−/−, and Tfr2Y245X/Y245X), hypotransferrinemia (Trfhpx/hpx), heterozygous transferrin receptor 1 deficiency (Tfrc+/−) and iron refractory iron deficiency anemia (Tmprss6−/− and Tmprss6hem8/hem8). Novel compound iron metabolism mutants were also phenotypically characterized here for the first time. We demonstrate that serum hepcidin concentrations correlate with liver hepcidin mRNA expression, transferrin saturation and non-heme liver iron. In some circumstances, serum hepcidin-1 more accurately predicts iron parameters than hepcidin mRNA, and distinguishes smaller, statistically significant differences between experimental groups. PMID:25425686

  4. Effect of standardized cranberry extract on the activity and expression of selected biotransformation enzymes in rat liver and intestine.

    PubMed

    Bártíková, Hana; Boušová, Iva; Jedličková, Pavla; Lněničková, Kateřina; Skálová, Lenka; Szotáková, Barbora

    2014-01-01

    The use of dietary supplements containing cranberry extract is a common way to prevent urinary tract infections. As consumption of these supplements containing a mixture of concentrated anthocyanins and proanthocyanidins has increased, interest in their possible interactions with drug-metabolizing enzymes has grown. In this in vivo study, rats were treated with a standardized cranberry extract (CystiCran®) obtained from Vaccinium macrocarpon in two dosage schemes (14 days, 0.5 mg of proanthocyanidins/kg/day; 1 day, 1.5 mg of proanthocyanidins/kg/day). The aim of this study was to evaluate the effect of anthocyanins and proanthocyanidins contained in this extract on the activity and expression of intestinal and hepatic biotransformation enzymes: cytochrome P450 (CYP1A1, CYP1A2, CYP2B and CYP3A), carbonyl reductase 1 (CBR1), glutathione-S-transferase (GST) and UDP-glucuronosyl transferase (UGT). Administration of cranberry extract led to moderate increases in the activities of hepatic CYP3A (by 34%), CYP1A1 (by 38%), UGT (by 40%), CBR1 (by 17%) and GST (by 13%), while activities of these enzymes in the small intestine were unchanged. No changes in the relative amounts of these proteins were found. Taken together, the interactions of cranberry extract with simultaneously administered drugs seem not to be serious. PMID:25237750

  5. The changing environment of graduate and postdoctoral training in drug metabolism: viewpoints from academia, industry, and government.

    PubMed

    Stevens, Jeffrey C; Dean, Dennis C; Preusch, Peter C; Correia, Maria Almira

    2003-04-01

    This article is an invited report of a symposium sponsored by the Drug Metabolism Division of the American Society for Pharmacology and Experimental Therapeutics held at Experimental Biology 2002 in New Orleans. The impetus for the symposium was a perceived shortage in the supply of graduate students qualified for drug metabolism research positions in industry, academia, and government. For industry, recent hiring stems largely from the expansion of drug metabolism departments in an effort to keep pace with the demands of drug discovery and new technologies. In turn, regulatory scientists are needed to review and verify the results of the increased number and volume of studies required for drug development and approval. Thus the initial source of training, academia, has been forced to recognize these external hiring pressures while trying to attract and retain the faculty, postdoctoral scientists, and students necessary for active teaching and research programs. The trend of the expansion of the interdisciplinary nature of traditional drug metabolism to include emerging technologies such as pharmacogenetics, transporters, and proteomics and the implications for future needs in training and funding were acknowledged. There was also consensus on the value of partnerships between academia and industry for increasing student interest and providing training in disciplines directly applicable to industrial drug metabolism research. Factors affecting the sources of these trainees, such as federal funding, the number of trainees per institution, and recent issues with immigration restrictions that have limited the flow of scientists were also discussed. PMID:12642460

  6. Insulin regulates enzyme activity, malonyl-CoA sensitivity and mRNA abundance of hepatic carnitine palmitoyltransferase-I.

    PubMed Central

    Park, E A; Mynatt, R L; Cook, G A; Kashfi, K

    1995-01-01

    The regulation of hepatic mitochondrial carnitine palmitoyltransferase-I (CPT-I) was studied in rats during starvation and insulin-dependent diabetes and in rat H4IIE cells. The Vmax. for CPT-I in hepatic mitochondrial outer membranes isolated from starved and diabetic rats increased 2- and 3-fold respectively over fed control values with no change in Km values for substrates. Regulation of malonyl-CoA sensitivity of CPT-I in isolated mitochondrial outer membranes was indicated by an 8-fold increase in Ki during starvation and by a 50-fold increase in Ki in the diabetic state. Peroxisomal and microsomal CPT also had decreased sensitivity to inhibition by malonyl-CoA during starvation. CPT-I mRNA abundance was 7.5 times greater in livers of 48-h-starved rats and 14.6 times greater in livers of insulin-dependent diabetic rats compared with livers of fed rats. In H4IIE cells, insulin increased CPT-I sensitivity to inhibition by malonyl-CoA in 4 h, and sensitivity continued to increase up to 24 h after insulin addition. CPT-I mRNA levels in H4IIE cells were decreased by insulin after 4 h and continued to decrease so that at 24 h there was a 10-fold difference. The half-life of CPT-I mRNA was 4 h in the presence of actinomycin D or with actinomycin D plus insulin. These results suggest that insulin regulates CPT-I by inhibiting transcription of the CPT-I gene. Images Figure 2 Figure 4 PMID:7575418

  7. Atorvastatin-induced acute elevation of hepatic enzymes and the absence of cross-toxicity of pravastatin

    PubMed Central

    Liu, Y.; Cheng, Z.; Ding, L.; Fang, F.; Cheng, K.-A.; Fang, Q.; Shi, G.-P.

    2011-01-01

    Atorvastatin has been associated with liver injury. We reported here two cases of aminotransferases elevation within 12 h of low-dose atorvastatin therapy. Liver functions were fully recovered to the baseline level 11 days after discontinuation of atorvastatin treatment. The possible relative risk factors included advanced age, chronic and systemic diseases, and co-administration of cytochrome P450 3A (CYP3A) enzyme-dependent metabolic drugs or its inhibitors such as clopidogrel and diltiazem. No significant transaminase elevation was observed after switching to pravastatin. Thus, pravastatin might be safer than atorvastain in patients with chronic or systemic diseases, or with co-administration of CYP3A enzyme-dependent drugs. PMID:21084035

  8. Dietary chia seed induced changes in hepatic transcription factors and their target lipogenic and oxidative enzyme activities in dyslipidaemic insulin-resistant rats.

    PubMed

    Rossi, Andrea S; Oliva, Maria E; Ferreira, Maria R; Chicco, Adriana; Lombardo, Yolanda B

    2013-05-01

    The present study analyses the effect of dietary chia seed rich in n-3 α-linolenic acid on the mechanisms underlying dyslipidaemia and liver steatosis developed in rats fed a sucrose-rich diet (SRD) for either 3 weeks or 5 months. The key hepatic enzyme activities such as fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), glucose-6-phosphate dehydrogenase (G-6-PDH), carnitine palmitoyltransferase-1 (CPT-1) and fatty acid oxidase (FAO) involved in lipid metabolism and the protein mass levels of sterol regulatory element-binding protein-1 (SREBP-1) and PPARα were studied. (1) For 3 weeks, Wistar rats were fed either a SRD with 11 % of maize oil (MO) as dietary fat or a SRD in which chia seed replaced MO (SRD+Chia). (2) A second group of rats were fed a SRD for 3 months. Afterwards, half the rats continued with the SRD while for the other half, MO was replaced by chia for 2 months (SRD+Chia). In a control group, maize starch replaced sucrose. Liver TAG and the aforementioned parameters were analysed in all groups. The replacement of MO by chia in the SRD prevented (3 weeks) or improved/normalised (5 months) increases in dyslipidaemia, liver TAG, FAS, ACC and G-6-PDH activities, and increased FAO and CPT-1 activities. Protein levels of PPARα increased, and the increased mature form of SREBP-1 protein levels in the SRD was normalised by chia in both protocols (1 and 2). The present study provides new data regarding some key mechanisms related to the fate of hepatic fatty acid metabolism that seem to be involved in the effect of dietary chia seed in preventing and normalising/improving dyslipidaemia and liver steatosis in an insulin-resistant rat model. PMID:22947172

  9. The Sterolgene v0 cDNA microarray: a systemic approach to studies of cholesterol homeostasis and drug metabolism

    PubMed Central

    Režen, Tadeja; Juvan, Peter; Fon Tacer, Klementina; Kuzman, Drago; Roth, Adrian; Pompon, Denis; Aggerbeck, Lawrence P; Meyer, Urs A; Rozman, Damjana

    2008-01-01

    Background Cholesterol homeostasis and xenobiotic metabolism are complex biological processes, which are difficult to study with traditional methods. Deciphering complex regulation and response of these two processes to different factors is crucial also for understanding of disease development. Systems biology tools as are microarrays can importantly contribute to this knowledge and can also discover novel interactions between the two processes. Results We have developed a low density Sterolgene v0 cDNA microarray dedicated to studies of cholesterol homeostasis and drug metabolism in the mouse. To illustrate its performance, we have analyzed mouse liver samples from studies focused on regulation of cholesterol homeostasis and drug metabolism by diet, drugs and inflammation. We observed down-regulation of cholesterol biosynthesis during fasting and high-cholesterol diet and subsequent up-regulation by inflammation. Drug metabolism was down-regulated by fasting and inflammation, but up-regulated by phenobarbital treatment and high-cholesterol diet. Additionally, the performance of the Sterolgene v0 was compared to the two commercial high density microarray platforms: the Agilent cDNA (G4104A) and the Affymetrix MOE430A GeneChip. We hybridized identical RNA samples to the commercial microarrays and showed that the performance of Sterolgene is comparable to commercial arrays in terms of detection of changes in cholesterol homeostasis and drug metabolism. Conclusion Using the Sterolgene v0 microarray we were able to detect important changes in cholesterol homeostasis and drug metabolism caused by diet, drugs and inflammation. Together with its next generations the Sterolgene microarrays represent original and dedicated tools enabling focused and cost effective studies of cholesterol homeostasis and drug metabolism. These microarrays have the potential of being further developed into screening or diagnostic tools. PMID:18261244

  10. Effects of orally applied butyrate bolus on histone acetylation and cytochrome P450 enzyme activity in the liver of chicken – a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Butyrate is known as histone deacetylase inhibitor, inducing histone hyperacetylation in vitro and playing a predominant role in the epigenetic regulation of gene expression and cell function. We hypothesized that butyrate, endogenously produced by intestinal microbial fermentation or applied as a nutritional supplement, might cause similar in vivo modifications in the chromatin structure of the hepatocytes, influencing the expression of certain genes and therefore modifying the activity of hepatic microsomal drug-metabolizing cytochrome P450 (CYP) enzymes. Methods An animal study was carried out in chicken as a model to investigate the molecular mechanisms of butyrate’s epigenetic actions in the liver. Broiler chicks in the early post-hatch period were treated once daily with orally administered bolus of butyrate following overnight starvation with two different doses (0.25 or 1.25 g/kg body weight per day) for five days. After slaughtering, cell nucleus and microsomal fractions were separated by differential centrifugation from the livers. Histones were isolated from cell nuclei and acetylation of hepatic core histones was screened by western blotting. The activity of CYP2H and CYP3A37, enzymes involved in biotransformation in chicken, was detected by aminopyrine N-demethylation and aniline-hydroxylation assays from the microsomal suspensions. Results Orally added butyrate, applied in bolus, had a remarkable impact on nucleosome structure of hepatocytes: independently of the dose, butyrate caused hyperacetylation of histone H2A, but no changes were monitored in the acetylation state of H2B. Intensive hyperacetylation of H3 was induced by the higher administered dose, while the lower dose tended to increase acetylation ratio of H4. In spite of the observed modification in histone acetylation, no significant changes were observed in the hepatic microsomal CYP2H and CYP3A37 activity. Conclusion Orally added butyrate in bolus could cause in vivo

  11. Nelumbo nucifera leaves protect hydrogen peroxide-induced hepatic damage via antioxidant enzymes and HO-1/Nrf2 activation.

    PubMed

    Je, Jae-Young; Lee, Da-Bin

    2015-06-01

    Naturally occurring phenolic compounds are widely found in plants. Here, the phenolic composition and hepatoprotective effect of the butanolic extract (BE) from Nelumbo nucifera leaves against H2O2-induced hepatic damage in cultured hepatocytes were investigated. BE showed high total phenol and flavonoid contents, and major phenolic compounds are quercetin, catechin, ferulic acid, rutin, and protocatechuic acid by HPLC analysis. BE effectively scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) cation radicals (IC50 values of 5.21 μg mL(-1) for DPPH and 6.22 μg mL(-1) for ABTS(+)) and showed strong reducing power. Pretreatment of BE prior to 650 μM H2O2 exposure markedly increased cell viability and suppressed H2O2-induced intracellular reactive oxygen species generation and AAPH-induced cell membrane lipid peroxidation. In addition, BE up-regulated intracellular glutathione levels under normal and oxidative stress conditions. Notably, the hepatoprotective effect of BE was directly correlated with the increased expression of superoxide dismutase-1 (SOD-1) by 0.62-fold, catalase (CAT) by 0.42-fold, and heme oxygenase-1 (HO-1) by 2.4-fold. Pretreatment of BE also increased the nuclear accumulation of Nrf2 by 8.1-fold indicating that increased SOD-1, CAT, and HO-1 expressions are Nrf2-mediated. PMID:25962859

  12. Etofenamate fatty acid asters. An example of a new route of drug metabolism.

    PubMed

    Dell, H D; Fielder, J; Kamp, R; Gau, W; Kurz, J; Weber, B; Wuensche, C

    1982-01-01

    Etofenamate [2-(2-hydroxyethoxy)ethyl-N-(alpha, alpha, alpha-trifluoro-m-tolyl)-anthranilate] was administered to dogs by the oral route. Minor amounts of etofenamate (Eto) and its glucuronide were found in urine and feces. The main portion of metabolites was eliminated as flufenamic acid (Flu) and hydroxy derivatives of Eto and Flu. Furthermore, a highly lipophilic fraction was isolated (extraction and TLC) and further separated into several compounds (HPLC, GLC). These metabolites were identified as Eto oleate, palmitate, linoleate, stearate, palmitoleate, myristate, and laurate by NMR and MS. The structures were confirmed by comparison with authentic material. The conjugation of etofenamate with fatty acids is an example of a new route of drug metabolism. PMID:6124384

  13. Early adventures in drug metabolism. 1. Role of the Bratton-Marshall reagent

    SciTech Connect

    Glazko, A.J.

    1987-01-01

    The Bratton-Marshall reagent is one of the real land-marks in the development of drug metabolism and pharmacokinetics, coming at a time when highly sensitive and specific analytical procedures were desperately needed for the measurement of drug concentrations in the body. Examples of its applications are taken from early work in the mid-40's and 50's in the Parke-Davis Research Laboratories, extending from primary aromatic amines (e.g., sulfonamides), to p-nitrophenyl compounds that must first be reduced to amines (e.g., chloramphenicol), and to phenyl derivatives that must be nitrated on a microgram scale and then reduced to aryl amines (e.g., phenytoin). The development and use of separation techniques such as liquid/liquid counter-current partition and paper chromatography is described. Emphasis is placed upon continued, progressive improvement in the basic assay procedures over long periods of time.

  14. The influence of triiodothyronine (T3) on the postnatal development of drug metabolism in rat liver.

    PubMed

    Müller, D; Greiling, K; Greiling, H; Klinger, W

    1983-01-01

    The influence of T3 on some cytochrome P-450-dependent biotransformation reactions (ethylmorphine N-demethylation, ethoxycoumarin O-deethylation and ethoxyresorufin O-deethylation) was investigated in rats of different ages. After T3 administrations on 3 consecutive days to rats of different ages, on the 4th day ethylmorphine N-demethylation rate was diminished in all age groups. On the contrary, ethoxyresorufin and ethoxycoumarin O-deethylation rates were considerably enhanced, preferentially in 33-day-old animals. The P-450 concentration was increased to a smaller degree. After T3 treatment on the first 8 days of life long-term effects on ethylmorphine N-demethylation were observed. Low T3 doses accelerated this reaction in 33- and 60-day-old rats. Ethoxycoumarin O-deethylation was not influenced. T3 administrations cannot diminish age-differences in drug metabolism. PMID:6651813

  15. Advances in the integration of drug metabolism into the lead optimization paradigm.

    PubMed

    Korfmacher, Walter A

    2009-06-01

    The lead optimization paradigm includes a team of experts that has a multitude of parameters to consider when moving from an initial lead compound through the lead optimization phase to the development phase. While in the past the team may have had only a medicinal chemist and a pharmacologist, the current team would often include experts in the areas of drug metabolism and pharmacokinetics (DMPK) as well as chemical toxicity. This review provides an overview of the some of the recent advances in the areas of DMPK screening plus a discussion of some of the assays that can be used to begin to screen for toxicity issues. The focus of this review is the major potential problem areas: oral bioavailability, half-life, drug-drug interactions and metabolism and toxicity issues. PMID:19519496

  16. Encapsulation of liver microsomes into a thermosensitive hydrogel for characterization of drug metabolism and toxicity.

    PubMed

    Yang, Huiying; Zheng, Yuanting; Zhao, Bei; Shao, Tengfei; Shi, Qingling; Zhou, Ning; Cai, Weimin

    2013-12-01

    This study reported the encapsulation of liver microsomes into a thermosensitive hydrogel to characterize drug metabolism and predict drug effects. Pluronic(®)F-127 (F127) and acrylamide-bisacrylamide (Acr-Bis) were utilized as the two precursors. After chemical crosslinking catalyzed by ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED), the resulting Pluronic F127-acrylamide-bisacrylamide (FAB) hydrogel could encapsulate microsomes at 4 °C and facilitate metabolic reactions at 37 °C. The gel morphology at different Acr-Bis concentrations was characterized using field emission scanning electron microscopy (FE-SEM). Higher concentrations of Acr-Bis could lead to higher degrees of cross-linking of the gel. A fluorescent staining assay was subsequently used to demonstrate successful encapsulation of microsomes into the gel as well as the free diffusion process of micromolecular substrates. The thermosensitivity of the FAB gel was studied using swelling ratio and protein release assay to verify its ability to encapsulate microsomes. The metabolic activity of microsomes encapsulated in gels was investigated by detecting the metabolites of FDA-approved substrates, including dextromethorphan, chlorzoxazone and testosterone. Compared with the traditional method of microsomal incubation, the FAB gel maintained 60%-70% of microsome activity. Lastly, the classic anticancer prodrug cyclophosphamide (CTX) was chosen as a model drug for the study of drug metabolism and the prediction of drug effects. When the microsomes encapsulated in the FAB gel were used in the cell culture system, CTX induced a higher level of apoptosis in MCF-7 cells compared with traditional microsomes. PMID:24075480

  17. Hepatic uptake and storage of warfarin. The relation with the target enzyme vitamin K 2,3-epoxide reductase

    SciTech Connect

    Thijssen, H.H.; Baars, L.G.

    1987-12-01

    The mechanisms of the reported dose-dependent warfarin pharmacokinetics were investigated using (/sup 14/C)warfarin. When administered in microdoses (9 micrograms i.v.) to rats (male Wistars, 270-300 g), a steep distribution phase (T1/2 = 0.25 hr) was followed by a relatively slow beta-phase (T1/2 = 40 hr). The observed volume of distribution was 390 ml. This pharmacokinetic behavior contrasted highly with the one seen for higher (greater than 0.2 mg/kg) doses (unlabeled) warfarin; volume of distribution = 45 ml, T1/2 = 12.5 hr. If a macrodose (0.2 mg/kg) preceded (16 hr) the microdose, normal pharmacokinetics were observed for the latter, suggesting a saturable deep compartment. The administration of 4-hydroxycoumarins (i.e., acenocoumarol, phenprocoumon and warfarin) after the microdose of (/sup 14/C)warfarin was in its beta-phase caused a rapid rise of plasma (/sup 14/C)warfarin indicating (/sup 14/C)warfarin to be displaced from the deep compartment. The rate of appearance of (/sup 14/C)warfarin was 0.3 hr-1 irrespective the 4-hydroxycoumarin used. The hepatic distribution of (/sup 14/C)warfarin was investigated and the effect of a displacer thereupon. Fifty-three hours after the (/sup 14/C)warfarin administration, the liver contained about 40% of the dose; 45% of it was bound to microsomes. The administration of acenocoumarol (0.2 mg/kg) at 48 hr, halved the liver content. (/sup 14/C)warfarin was redistributed from microsomes (-65%) and from the 10,000 X g pellet (-65%) into the cytosol (+260%) and the plasma (+320%). Microsomal bound (/sup 14/C)warfarin in vitro could not be washed out or be displaced unless dithiothreitol (50 mM) was included in the washing buffers.

  18. The enzymes LSD1 and Set1A cooperate with the viral protein HBx to establish an active hepatitis B viral chromatin state.

    PubMed

    Alarcon, Valentina; Hernández, Sergio; Rubio, Lorena; Alvarez, Francisca; Flores, Yvo; Varas-Godoy, Manuel; De Ferrari, Giancarlo V; Kann, Michael; Villanueva, Rodrigo A; Loyola, Alejandra

    2016-01-01

    With about 350 million people chronically infected around the world hepatitis B is a major health problem. Template for progeny HBV synthesis is the viral genome, organized as a minichromosome (cccDNA) inside the hepatocyte nucleus. How viral cccDNA gene expression is regulated by its chromatin structure; more importantly, how the modulation of this structure impacts on viral gene expression remains elusive. Here, we found that the enzyme SetDB1 contributes to setting up a repressed cccDNA chromatin state. This repressive state is activated by the histone lysine demethylase-1 (LSD1). Consistently, inhibiting or reducing LSD1 levels led to repression of viral gene expression. This correlates with the transcriptionally repressive mark H3K9 methylation and reduction on the activating marks H3 acetylation and H3K4 methylation on viral promoters. Investigating the importance of viral proteins we found that LSD1 recruitment to viral promoters was dependent on the viral transactivator protein HBx. Moreover, the histone methyltransferase Set1A and HBx are simultaneously bound to the core promoter, and Set1A expression correlates with cccDNA H3K4 methylation. Our results shed light on the mechanisms of HBV regulation mediated by the cccDNA chromatin structure, offering new therapeutic targets to develop drugs for the treatment of chronically infected HBV patients. PMID:27174370

  19. The enzymes LSD1 and Set1A cooperate with the viral protein HBx to establish an active hepatitis B viral chromatin state

    PubMed Central

    Alarcon, Valentina; Hernández, Sergio; Rubio, Lorena; Alvarez, Francisca; Flores, Yvo; Varas-Godoy, Manuel; De Ferrari, Giancarlo V.; Kann, Michael; Villanueva, Rodrigo A.; Loyola, Alejandra

    2016-01-01

    With about 350 million people chronically infected around the world hepatitis B is a major health problem. Template for progeny HBV synthesis is the viral genome, organized as a minichromosome (cccDNA) inside the hepatocyte nucleus. How viral cccDNA gene expression is regulated by its chromatin structure; more importantly, how the modulation of this structure impacts on viral gene expression remains elusive. Here, we found that the enzyme SetDB1 contributes to setting up a repressed cccDNA chromatin state. This repressive state is activated by the histone lysine demethylase-1 (LSD1). Consistently, inhibiting or reducing LSD1 levels led to repression of viral gene expression. This correlates with the transcriptionally repressive mark H3K9 methylation and reduction on the activating marks H3 acetylation and H3K4 methylation on viral promoters. Investigating the importance of viral proteins we found that LSD1 recruitment to viral promoters was dependent on the viral transactivator protein HBx. Moreover, the histone methyltransferase Set1A and HBx are simultaneously bound to the core promoter, and Set1A expression correlates with cccDNA H3K4 methylation. Our results shed light on the mechanisms of HBV regulation mediated by the cccDNA chromatin structure, offering new therapeutic targets to develop drugs for the treatment of chronically infected HBV patients. PMID:27174370

  20. Diminution of Hepatic Response to 7, 12-dimethylbenz(α)anthracene by Ethyl Acetate Fraction of Acacia catechu Willd. through Modulation of Xenobiotic and Anti-Oxidative Enzymes in Rats

    PubMed Central

    Kumar, Rakesh; Kaur, Rajbir; Singh, Amrit Pal; Arora, Saroj

    2014-01-01

    Background Liver is the primary metabolizing site of body and is prone to damage by exogenous as well as endogenous intoxicants. Polycyclic aromatic hydrocarbons such as 7, 12- dimethylbenz(α)anthracene (DMBA) is an exogenous hepatotoxin, which is well known for modulating phase I, II and anti-oxidative enzymes of liver. Plants contain plethora of polyphenolic compounds which can reverse the damaging effect of various xenobiotics. The present study investigated protective role of the ethyl acetate fraction of Acacia catechu Willd. (EAF) against DMBA induced alteration in hepatic metabolizing and anti-oxidative enzymes in rats. Methodology and Principal Findings The rats were subjected to hepatic damage by treating with DMBA for 7 weeks on alternative days and treatment schedule was terminated at the end of 14 weeks. The rats were euthanized at the end of protocol and livers were homogenized. The liver homogenates were used to analyse phase I (NADPH-cytochrome P450 reducatse, NADH-cytochrome b5 reductase, cytochrome P420, cytochrome b5), phase II (glutathione-S-transferase, DT diaphorase and γ-Glutamyl transpeptidase) and antioxidative enzymes (catalase, superoxide dismutase, ascorbate peroxidase, glutathione reductase, guiacol peroxidase and lactate dehydrogenase). Furthermore, other oxidative stress parameters (thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes and reduced glutathione) and liver marker enzymes (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and alkaline phosphatase) were also studied. The DMBA induced significant changes in activity of hepatic enzymes that was reversed by treatment with three dose levels of EAF. Conclusion It is concluded that EAF affords hepato-protection against DMBA in rats through modulation of phase I, II and anti-oxidative enzymes. PMID:24587216

  1. Differential regulation of detoxification enzymes in hepatic and mammary tissue by hops (Humulus lupulus) in vitro and in vivo

    PubMed Central

    Dietz, Birgit M.; Hagos, Ghenet K.; Eskra, Jillian N.; Wijewickrama, Gihani T.; Anderson, Jeffrey R.; Nikolic, Dejan; Guo, Jian; Wright, Brian; Chen, Shao-Nong; Pauli, Guido F.; van Breemen, Richard B.; Bolton, Judy L.

    2013-01-01

    Scope Hops contain the phytoestrogen, 8-prenylnaringenin, and the cytoprotective compound, xanthohumol (XH). XH induces the detoxification enzyme, NAD(P)H-quinone oxidoreductase (NQO1) in vitro; however, the tissue distribution of XH and 8-prenylnaringenin and their tissue specific activity have not been analyzed. Methods and results A standardized hop extract (p.o.) and XH (s.c.) were administered to Sprague-Dawley rats over four days. LC-MS-MS analysis of plasma, liver and mammary gland revealed that XH accumulated in liver and mammary glands. Compared with the low level in the original extract, 8-prenylnaringenin was enriched in the tissues. Hops and XH induced NQO1 in the liver, while only hops reduced NQO1 activity in the mammary gland. Mechanistic studies revealed that hops modulated NQO1 through three mechanisms. In liver cells, 1) XH modified Keap1 leading to Nrf2 translocation and antioxidant response element (ARE) activation; 2) hop-mediated ARE induction was partially mediated through phosphorylation of Nrf2 by PKC; 3) in breast cells, 8-prenylnaringenin reduced NQO1 likely through binding to ERα, recruiting Nrf2, and downregulating ARE-regulated genes. Conclusions XH and 8-prenylnaringenin in dietary hops are bioavailable to the target tissues. While hops and XH might be cytoprotective in the liver, 8-prenylnaringenin seems responsible for hop-mediated NQO1 reduction in the mammary gland. PMID:23512484

  2. Multiple mechanisms regulate circadian expression of the gene for cholesterol 7alpha-hydroxylase (Cyp7a), a key enzyme in hepatic bile acid biosynthesis.

    PubMed

    Noshiro, Mitsuhide; Usui, Emiko; Kawamoto, Takeshi; Kubo, Hiroshi; Fujimoto, Katsumi; Furukawa, Masae; Honma, Sato; Makishima, Makoto; Honma, Ken-ichi; Kato, Yukio

    2007-08-01

    Cholesterol 7alpha-hydroxylase (CYP7A) and sterol 12alpha-hydroxylase (CYP8B) in bile acid biosynthesis and 3-hydroxyl-3-methylglutaryl CoA reductase (HMGCR) in cholesterol biosynthesis are the key enzymes in hepatic metabolic pathways, and their transcripts exhibit circadian expression profiles in rodent liver. The authors determined transcript levels of these enzymes and the regulatory factors for Cyp7a--including Dbp, Dec2, E4bp4, Hnf4alpha, Pparalpha, Lxralpha, Rev-erbalpha, and Rev-erbbeta--in the liver of wild-type and homozygous Clock mutant mice (Clock/Clock) and examined the effects of these transcription factors on the transcription activities of Cyp7a. The expression profile of the Cyp7a transcript in wild-type mice showed a strong circadian rhythm in both the 12L:12D light-dark cycle and constant darkness, and that in Clock/Clock also exhibited a circadian rhythm at an enhanced level with a lower amplitude, although its protein level became arrhythmic at a high level. The expression profile of Cyp8b mRNA in wild-type mice showed a shifted circadian rhythm from that of Cyp7a, becoming arrhythmic in Clock/Clock at an expression level comparable to that of wild-type mice. The expression profile of Hmgcr mRNA also lost its strong circadian rhythm in Clock/Clock , showing an expression level comparable to that of wild-type mice. The expressions of Dbp, Dec2, Rev-erbalpha, and Rev-erb beta--potent regulators for Cyp7a expression--were abolished or became arrhythmic in Clock/Clock, while other regulators for Cyp7a-Lxralpha, Hnf4alpha, Pparalpha, and E4bp4--had either less affected or enhanced expression in Clock/Clock. In luciferase reporter assays, REV-ERBalpha/beta, DBP, LXRalpha, and HNF4alpha increased the promoter activity of Cyp7a, whereas DEC2 abolished the transcription from the Cyp7a promoter: E4BP4 and PPARalpha were moderate negative regulators. Furthermore, knockdown of REV-ERBalpha/beta with siRNA suppressed Cyp7a transcript levels, and in the

  3. A novel matrix for the short-term storage of cells: utility in drug metabolism and drug transporter studies with rat, dog and human hepatocytes.

    PubMed

    Palmgren, Anna-Pia; Fihn, Britt-Marie; Bird, James; Courtney, Paul; Grime, Ken

    2013-06-01

    1. The SureTran matrix is a novel method facilitating short-term maintenance of fresh primary hepatocyte cellular function and offers the potential use of primary cells "as fresh" for several days post isolation. In the study presented, the maintenance of several key phase I and II drug metabolizing enzyme and drug transporter activities is demonstrated with rat and dog hepatocytes preserved for up to 7 days after cell isolation. 2. Intrinsic clearance values were determined for 60 new chemical entities using rat hepatocytes freshly isolated at AstraZeneca and rat hepatocytes prepared at the facilities of Abcellute Ltd (SureTran purveyors), stored and incubated 24 hours after isolation. A very good correspondence in the intrinsic clearance values underlines the utility of the cell maintenance matrix. 3. For human hepatocytes many of the enzyme activities assayed were well maintained for 7 days of storage but some declined to below 50% of initial values between day 4 and 7 of storage. Human OATP1B1 activity was only determined with one batch and declined to 51% of the initial test value by day 4 and further down to 35% by day 7. PMID:23137276

  4. Regulation of hepatic energy metabolism by the nuclear receptor PXR.

    PubMed

    Hakkola, Jukka; Rysä, Jaana; Hukkanen, Janne

    2016-09-01

    The pregnane X receptor (PXR) is a nuclear receptor that is traditionally thought to be specialized for sensing xenobiotic exposure. In concurrence with this feature PXR was originally identified to regulate drug-metabolizing enzymes and transporters. During the last ten years it has become clear that PXR harbors broader functions. Evidence obtained both in experimental animals and humans indicate that ligand-activated PXR regulates hepatic glucose and lipid metabolism and affects whole body metabolic homeostasis. Currently, the consequences of PXR activation on overall metabolic health are not yet fully understood and varying results on the effect of PXR activation or knockout on metabolic disorders and weight gain have been published in mouse models. Rifampicin and St. John's wort, the prototypical human PXR agonists, impair glucose tolerance in healthy volunteers. Chronic exposure to PXR agonists could potentially represent a risk factor for diabetes and metabolic syndrome. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie. PMID:27041449

  5. COMPARISON OF IN VITRO AND IN VIVO METHODS FOR EVALUATING ALTERATIONS IN HEPATIC DRUG METABOLISM FOLLOWING MERCURIC CHLORIDE ADMINISTRATION

    EPA Science Inventory

    Mercuric chloride was administered once ip to female Fischer 344 rats at doses of 0, 0.2, 0.6, and 1.8 mg/kg. Although there were no alterations in the urinary excretion of lactate dehydrogenase, significant elevations in the activities of urinary alkaline phosphatase, glutamicpy...

  6. The influence of triiodothyronine (T3) and inducers on hepatic drug metabolism in rats of different ages.

    PubMed

    Müller, D; Greiling, K; Greiling, H; Klinger, W

    1985-01-01

    After a 3-day treatment with T3 the ethylmorphine N-demethylation rate was diminished in 10- to 60-day-old rats, whereas the ethoxycoumarin O-deethylation rate was distinctly enhanced in some age-groups, particularly in 33-day-old rats. P-450 concentration was decreased in young rats and not changed in 60-day-old ones. Phenobarbital administration enhanced the rate of both reactions and P-450 concentration in all age-groups. This treatment significantly attenuated the T3 effects on P-450 concentration and ethylmorphine N-demethylation. beta-Naphthoflavone induced ethoxycoumarin O-deethylation and P-450 concentration in all age-groups. Compared with non-induced animals, the T3 effects on ethoxycoumarin O-deethylation (increase) and ethylmorphine N-demethylation (decrease) were more distinct, whereas P-450 concentration was scarcely influenced by T3. Age-differences in T3 actions were generally diminished by inducers. PMID:4084270

  7. Liver microsomal drug-metabolizing enzyme activity: enhancement by blockade of degradative processes in promethazine-treated rats.

    PubMed Central

    Fernández, G.; Villarruel, M. C.; Bernacchi, A.; de Castro, C. R.; Castro, J. A.

    1981-01-01

    Daily injection of promethazine over 4 days significantly increased the liver cytochrome P-450 content and ethyl morphine N-demethylase activity. These increases were evident after the first dose and were prevented by puromycin or actinomycin D administration. Repeated administration of promethazine does not increase the liver's ability to incorporate [14]C DL-leucine in microsomes but slows down the decay of radioactivity in microsomes previously labelled with ([14C]-guanidino) arginine. Repeated treatment with promethazine leads to a marked proliferation of the rough endoplasmic reticulum (RER) and a slight increase in the smooth endoplasmic reticulum (SER). Our findings suggest that the enhancement of P-450 and EM-ase activity result from the decelerating effect of promethazine on protein degradation. Images Fig. 1 Fig. 2 PMID:7295538

  8. Efficient episomal reprogramming of blood mononuclear cells and differentiation to hepatocytes with functional drug metabolism.

    PubMed

    Liu, Jing; Brzeszczynska, Joanna; Samuel, Kay; Black, Jim; Palakkan, Anwar; Anderson, Richard A; Gallagher, Ronald; Ross, James A

    2015-11-01

    The possibility of converting cells from blood mononuclear cells (MNC) to liver cells provides promising opportunities for the study of diseases and the assessment of new drugs. However, clinical applications have to meet GMP requirements and the methods for generating induced pluripotent cells (iPCs) have to avoid insertional mutagenesis, a possibility when using viral vehicles for the delivery of reprogramming factors. We have developed an efficient non-integration method for reprogramming fresh or frozen blood MNC, maintained in an optimised cytokine cocktail, to generate induced pluripotent cells. Using electroporation for the effective delivery of episomal transcription factors (Oct4, Sox2, Klf4, L-Myc, and Lin28) in a feeder-free system, without any requirement for small molecules, we achieved a reprogramming efficiency of up to 0.033% (65 colonies from 2×10(5) seeded MNC). Applying the same cytokine cocktail and reprogramming methods to cord blood or fetal liver-derived CD34(+) cells, we obtained 148 iPS colonies from 10(5) seeding cells (0.148%). The iPS cell lines we generated maintained typical characteristics of pluripotent cells and could be successfully differentiated into hepatocytes with drug metabolic function. PMID:26256888

  9. Effects of Nonalcoholic Fatty Liver Disease on Hepatic CYP2B1 and in Vivo Bupropion Disposition in Rats Fed a High-Fat or Methionine/Choline-Deficient Diet.

    PubMed

    Cho, Sung-Joon; Kim, Sang-Bum; Cho, Hyun-Jong; Chong, Saeho; Chung, Suk-Jae; Kang, Il-Mo; Lee, Jangik Ike; Yoon, In-Soo; Kim, Dae-Duk

    2016-07-13

    Nonalcoholic fatty liver disease (NAFLD) refers to hepatic pathologies, including simple fatty liver (SFL), nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis, that may progress to hepatocellular carcinoma. These liver disease states may affect the activity and expression levels of drug-metabolizing enzymes, potentially resulting in an alteration in the pharmacokinetics, therapeutic efficacy, and safety of drugs. This study investigated the hepatic cytochrome P450 (CYP) 2B1-modulating effect of a specific NAFLD state in dietary rat models. Sprague-Dawley rats were given a methionine/choline-deficient (MCD) or high-fat (HF) diet to induce NASH and SFL, respectively. The induction of these disease states was confirmed by plasma chemistry and liver histological analysis. Both the protein and mRNA levels of hepatic CYP2B1 were considerably reduced in MCD diet-fed rats; however, they were similar between the HF diet-fed and control rats. Consistently, the enzyme-kinetic and pharmacokinetic parameters for CYP2B1-mediated bupropion metabolism were considerably reduced in MCD diet-fed rats; however, they were also similar between the HF diet-fed and control rats. These results may promote a better understanding of the influence of NAFLD on CYP2B1-mediated metabolism, which could have important implications for the safety and pharmacokinetics of drug substrates for the CYP2B subfamily in patients with NAFLD. PMID:27321734

  10. Chemiluminescence enzyme immunoassay for monitoring hepatitis C virus core protein during interferon-alpha2b and ribavirin therapy in patients with genotype 1 and high viral loads.

    PubMed

    Enomoto, Masaru; Nishiguchi, Shuhei; Tamori, Akihiro; Kohmoto, Modoka; Habu, Daiki; Sakaguchi, Hiroki; Takeda, Tadashi; Kawada, Norifumi; Seki, Shuichi; Shiomi, Susumu

    2005-09-01

    This study evaluated an updated chemiluminescence enzyme immunoassay (CLEIA) for hepatitis C virus (HCV) core protein for monitoring viral kinetics during treatment with interferon (IFN)-alpha and ribavirin. Using the CLEIA, serum levels of HCV core protein were measured in 17 patients with genotype 1 and high baseline viral loads during the first 4 weeks of combination therapy. HCV RNA was measured by the Amplicor Monitor test for comparison. At the start of therapy, the median HCV level (interquartile range) was 700 (540-940) kIU/ml of viral RNA and 11,310 (5,528-14,238) fmol/L of core protein. HCV RNA was above the upper limit of the linear range of the Amplicor Monitor test in 13 of the 17 patients, while the core protein level was within the linear range of the CLEIA in all patients. During therapy, the proportion of patients with HCV levels below the cutoff values at each time point was less with the Amplicor Monitor test than with CLEIA. Serum HCV core protein level decreased rapidly during the first 24 hr of therapy and more slowly thereafter, with median exponential decays of 1.08 and 0.046 log10/day, respectively. In the second phase, between day 1 and 28, the median decrease in HCV core protein level was higher in four patients with sustained virologic response (0.13 log10/day) than in 13 patients with no response (0.028 log10/day, P = 0.042). The wide linear range of the HCV core protein assay is appropriate for measuring viral loads during therapy with IFN-alpha and ribavirin. PMID:16032731

  11. Structure-based rational design of peptide hydroxamic acid inhibitors to target tumor necrosis factor-α converting enzyme as potential therapeutics for hepatitis.

    PubMed

    Wu, Dan; Gu, Qiuhong; Zhao, Ning; Xia, Fei; Li, Zhiwei

    2015-12-01

    The human tumor necrosis factor-α converting enzyme (TACE) has recently been raised as a new and promising therapeutic target of hepatitis and other inflammatory diseases. Here, we reported a successful application of the solved crystal structure of TACE complex with a peptide-like ligand INN for rational design of novel peptide hydroxamic acid inhibitors with high potency and selectivity to target and inhibit TACE. First, the intermolecular interactions between TACE catalytic domain and INN were characterized through an integrated bioinformatics approach, with which the key substructures of INN that dominate ligand binding were identified. Subsequently, the INN molecular structure was simplified to a chemical sketch of peptide hydroxamic acid compound, which can be regarded as a linear tripeptide capped by a N-terminal carboxybenzyl group (chemically protective group) and a C-terminal hydroxamate moiety (coordinated to the Zn(2+) at TACE active site). Based on the sketch, a virtual combinatorial library containing 180 peptide hydroxamic acids was generated, from which seven samples were identified as promising candidates by using a knowledge-based protein-peptide affinity predictor and were then tested in vitro with a standard TACE activity assay protocol. Consequently, three designed peptide hydroxamic acids, i.e. Cbz-Pro-Ile-Gln-hydroxamic acid, Cbz-Leu-Ile-Val-hydroxamic acid and Cbz-Phe-Val-Met-hydroxamic acid, exhibited moderate or high inhibitory activity against TACE, with inhibition constants Ki of 36 ± 5, 510 ± 46 and 320 ± 26 nM, respectively. We also examined the structural basis and non-bonded profile of TACE interaction with a designed peptide hydroxamic acid inhibitor, and found that the inhibitor ligand is tightly buried in the active pocket of TACE, forming a number of hydrogen bonds, hydrophobic forces and van der Waals contacts at the interaction interface, conferring both stability and specificity for TACE-inhibitor complex

  12. The inhibition of major human hepatic cytochrome P450 enzymes by 18 pesticides: comparison of the N-in-one and single substrate approaches.

    PubMed

    Abass, Khaled; Pelkonen, Olavi

    2013-08-01

    In the present study on human hepatic microsomes, the N-in-one assay with ten probe substrates for nine cytochrome-P450 enzymes (CYPs) was compared with the single substrate assays to investigate pesticides-CYP interactions. CYP inhibition was measured by liquid chromatography-tandem mass spectrometry (LC/MS-MS). As illustrated by the initial screening at 100 μM concentration of 18 pesticides, CYPs are more sensitive to organophosphates (OPs) than to other pesticide groups. Chlorpyrifos and fenitrothion were most effective in inhibiting CYP1A1/2, and CYP2B6. Profenofos was also inhibitory towards multiple CYPs. Pyrethroids, e.g. deltamethrin, fenvalerate and lambda-cyhalothrin, potently inhibited CYP2D6. CYP3A4 activity was moderately inhibited by fenvalerate and potently by alpha-cypermethrin. The correlations between IC50 values obtained from the N-in-one and single substrate approaches were highly significant for CYP2Cs (r(2)=0.94), CYP3A4, omeprazole-sulfoxidation, (r(2)=0.89), followed by CYP1A2 and CYP2B6 (r(2)=0.82), and CYP2D6 (r(2)=0.80). In contrast no correlation was observed with CYP2E1 and CYP3A4 (midazolam-1'-hydroxylation). The N-in-one screening assay seems useful and reliable for most CYP activities when a comprehensive and quick evaluation of potential interactions with CYPs is needed. However, at the present moment, it does not enable discrimination on the basis of mechanism of inhibition. A strict comparison between single and N-in-one assays is a prerequisite for more extensive routine use. PMID:22634058

  13. S-adenosyl-L-methionine modifies antioxidant-enzymes, glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells

    PubMed Central

    Lozano-Sepulveda, Sonia Amelia; Bautista-Osorio, Eduardo; Merino-Mascorro, Jose Angel; Varela-Rey, Marta; Muñoz-Espinosa, Linda Elsa; Cordero-Perez, Paula; Martinez-Chantar, María Luz; Rivas-Estilla, Ana Maria

    2016-01-01

    AIM: To elucidate the mechanism(s) by which S-adenosyl-L-methionine (SAM) decreases hepatitis C virus (HCV) expression. METHODS: We examined the effects of SAM on viral expression using an HCV subgenomic replicon cell culture system. Huh7 HCV-replicon cells were treated with 1 mmol/L SAM for different times (24-72 h), then total RNA and proteins were isolated. cDNA was synthesized and real time-PCR was achieved to quantify HCV-RNA, superoxide dismutase 1 and 2 (SOD-1, SOD-2) catalase, thioredoxin 1, methionine adenosyltransferase 1A and 2A (MAT1A, MAT2A) expression, and GAPDH and RPS18 as endogenous genes. Expression of cellular and viral protein was evaluated by western-blot analysis using antibodies vs HCV-NS5A, SOD-1, SOD-2, catalase, thioredoxin-1, MAT1A, MAT2A, GAPDH and actin. Total glutathione levels were measured at different times by Ellman’s recycling method (0-24 h). Reactive oxidative species (ROS) levels were quantified by the dichlorofluorescein assay (0-48 h); Pyrrolidin dithiocarbamate (PDTC) was tested as an antioxidant control and H2O2 as a positive oxidant agent. RESULTS: SAM exposition decreased HCV-RNA levels 50%-70% compared to non-treated controls (24-72 h). SAM induced a synergic antiviral effect with standard IFN treatment but it was independent of IFN signaling. In addition, 1 mmol/L SAM exposition did not modify viral RNA stability, but it needs cellular translation machinery in order to decrease HCV expression. Total glutathione levels increased upon SAM treatment in HCV-replicon cells. Transcriptional antioxidant enzyme expression (SOD-1, SOD-2 and thioredoxin-1) was increased at different times but interestingly, there was no significant change in ROS levels upon SAM treatment, contrary to what was detected with PDTC treatment, where an average 40% reduction was observed in exposed cells. There was a turnover from MAT1A/MAT2A, since MAT1A expression was increased (2.5 fold-times at 48 h) and MAT2A was diminished (from 24 h) upon SAM

  14. Hepatocyte spheroid culture on fibrous scaffolds with grafted functional ligands as an in vitro model for predicting drug metabolism and hepatotoxicity.

    PubMed

    Yan, Shili; Wei, Jiaojun; Liu, Yaowen; Zhang, Hong; Chen, Jianmei; Li, Xiaohong

    2015-12-01

    The identification of a biologic substrate for maintaining hepatocyte functions is essential to provide reliable and predictable models for in vitro drug screening. In the current study, a three-dimensional culture of hepatocytes was established on highly porous fibrous scaffolds with grafted galactose and RGD to afford extensive cell-cell and cell-scaffold interactions spatially. The pore size and ligand densities indicated significant effects on the formation of hepatocyte spheroids in balancing the cell retention, adhesion, and migration on fibrous scaffolds. Fibrous scaffolds with an average pore size of 60 μm and surface grafting densities of galactose at 5.9 nmol/cm(2) and RGD at 6.9 pmol/cm(2) provided optimal microenvironments for hepatocyte infiltration and multicellular spheroid formation. Significant promotions were also demonstrated in the syntheses of albumin and urea and the activities of phase I (CYP 3A11 and CYP 2C9) and phase II enzymes. The in vitro metabolism tests on testosterone and acetaminophen by hepatocytes on the optimal scaffolds indicated the predicated clearance rates of 50.7 and 22.6 ml/min/kg, respectively, which were comparable to the in vivo values of rats. The in vitro hepatotoxicity tests on amiodarone hydrochloride and acetaminophen predicted the half maximal effective concentrations (EC50) to reflect the in vivo toxic plasma concentrations in human. In addition, the enzyme activities, predicted clearance rates and hepatotoxicity values of hepatocytes on the optimal scaffolds experienced sensitive responsiveness to specific inducers or inhibitors of CYP 3A11 and phase II enzymes, exhibiting in vivo-in vitro correlations to a certain extent. These results demonstrate the feasibility of hepatocyte spheroid culture on fibrous scaffolds as an potential in vitro testing model to predict the in vivo drug metabolism, hepatotoxicity, and drug-drug interactions. PMID:26409440

  15. Heteronuclear 19F-1H statistical total correlation spectroscopy as a tool in drug metabolism: study of flucloxacillin biotransformation.

    PubMed

    Keun, Hector C; Athersuch, Toby J; Beckonert, Olaf; Wang, Yulan; Saric, Jasmina; Shockcor, John P; Lindon, John C; Wilson, Ian D; Holmes, Elaine; Nicholson, Jeremy K

    2008-02-15

    We present a novel application of the heteronuclear statistical total correlation spectroscopy (HET-STOCSY) approach utilizing statistical correlation between one-dimensional 19F/1H NMR spectroscopic data sets collected in parallel to study drug metabolism. Parallel one-dimensional (1D) 800 MHz 1H and 753 MHz 19F{1H} spectra (n = 21) were obtained on urine samples collected from volunteers (n = 6) at various intervals up to 24 h after oral dosing with 500 mg of flucloxacillin. A variety of statistical relationships between and within the spectroscopic datasets were explored without significant loss of the typically high 1D spectral resolution, generating 1H-1H STOCSY plots, and novel 19F-1H HET-STOCSY, 19F-19F STOCSY, and 19F-edited 1H-1H STOCSY (X-STOCSY) spectroscopic maps, with a resolution of approximately 0.8 Hz/pt for both nuclei. The efficient statistical editing provided by these methods readily allowed the collection of drug metabolic data and assisted structure elucidation. This approach is of general applicability for studying the metabolism of other fluorine-containing drugs, including important anticancer agents such as 5-fluorouracil and flutamide, and is extendable to any drug metabolism study where there is a spin-active X-nucleus (e.g., 13C, 15N, 31P) label present. PMID:18211034

  16. Application of a Micropatterned Cocultured Hepatocyte System To Predict Preclinical and Human-Specific Drug Metabolism.

    PubMed

    Ballard, T Eric; Wang, Shuai; Cox, Loretta M; Moen, Mark A; Krzyzewski, Stacy; Ukairo, Okechukwu; Obach, R Scott

    2016-02-01

    Laboratory animal models are the industry standard for preclinical risk assessment of drug candidates. Thus, it is important that these species possess profiles of drug metabolites that are similar to those anticipated in human, since metabolites also could be responsible for biologic activities or unanticipated toxicity. Under most circumstances, preclinical species reflect human in vivo metabolites well; however, there have been several notable exceptions, and understanding and predicting these exceptions with an in vitro system would be very useful. Human micropatterned cocultured (MPCC) hepatocytes have been shown to recapitulate human in vivo qualitative metabolic profiles, but the same demonstration has not been performed yet for laboratory animal species. In this study, we investigated several compounds that are known to produce human-unique metabolites through CYP2C9, UGT1A4, aldehyde oxidase (AO), or N-acetyltransferase that were poorly covered or not detected at all in the selected preclinical species. To perform our investigation we used 24-well MPCC hepatocyte plates having three individual human donors and a single donor each of monkey, dog, and rat to study drug metabolism at four time points per species. Through the use of the multispecies MPCC hepatocyte system, the metabolite profiles of the selected compounds in human donors effectively captured the qualitative in vivo metabolite profile with respect to the human metabolite of interest. Human-unique metabolites that were not detected in vivo in certain preclinical species (normally dog and rat) were also not generated in the corresponding species in vitro, confirming that the MPCC hepatocytes can provide an assessment of preclinical species metabolism. From these results, we conclude that multispecies MPCC hepatocyte plates could be used as an effective in vitro tool for preclinical understanding of species metabolism relative to humans and aid in the choice of appropriate preclinical models. PMID

  17. Does an extract of carob (Ceratonia siliqua L.) have chemopreventive potential related to oxidative stress and drug metabolism in human colon cells?

    PubMed

    Klenow, Stefanie; Jahns, Franziska; Pool-Zobel, Beatrice L; Glei, Michael

    2009-04-01

    Phenolic ingredients of an aqueous carob extract are well characterized and consist of mainly gallic acid (GA). In order to assess possible chemopreventive mechanisms of carob, which can be used as a cacao substitute, effects on expression of genes related to stress response and drug metabolism were studied using human colon cell lines of different transformation state (LT97 and HT29). Stress-related genes, namely catalase (CAT) and superoxide dismutase (SOD2), were induced by carob extract and GA in LT97 adenoma, but not in HT29 carcinoma cells. Although corresponding protein products and enzyme activities were not elevated, pretreatment with carob extract and GA for 24 h reduced DNA damage in cells challenged with hydrogen peroxide (H(2)O(2)). In conclusion, carob extract and its major phenolic ingredient GA modulate gene expression and protect colon adenoma cells from genotoxic impact of H(2)O(2). Upregulation of stress-response genes could not be related to functional consequences. PMID:19296575

  18. Effect of High Dietary Carbohydrate on the Growth Performance, Blood Chemistry, Hepatic Enzyme Activities and Growth Hormone Gene Expression of Wuchang Bream (Megalobrama amblycephala) at Two Temperatures

    PubMed Central

    Zhou, Chuanpeng; Ge, Xianping; Liu, Bo; Xie, Jun; Chen, Ruli; Ren, Mingchun

    2015-01-01

    The effects of high carbohydrate diet on growth, serum physiological response, and hepatic heat shock protein 70 expression in Wuchang bream were determined at 25°C and 30°C. At each temperature, the fish fed the control diet (31% CHO) had significantly higher weight gain, specific growth rate, protein efficiency ratio and hepatic glucose-6-phosphatase activities, lower feed conversion ratio and hepatosomatic index (HSI), whole crude lipid, serum glucose, hepatic glucokinase (GK) activity than those fed the high-carbohydrate diet (47% CHO) (p<0.05). The fish reared at 25°C had significantly higher whole body crude protein and ash, serum cholesterol and triglyceride, hepatic G-6-Pase activity, lower glycogen content and relative levels of hepatic growth hormone (GH) gene expression than those reared at 30°C (p<0.05). Significant interaction between temperature and diet was found for HSI, condition factor, hepatic GK activity and the relative levels of hepatic GH gene expression (p<0.05). PMID:25557816

  19. Double-Antigen Enzyme-Linked Immunosorbent Assay for Detection of Hepatitis E Virus-Specific Antibodies in Human or Swine Sera ▿

    PubMed Central

    Hu, Wei Ping; Lu, Yang; Precioso, Nestor Amadeo; Chen, Hsiao Ying; Howard, Teresa; Anderson, David; Guan, Ming

    2008-01-01

    A new double-antigen sandwich-based enzyme-linked immunosorbent assay (ELISA) for the detection of total antibodies (immunoglobulin G [IgG] and IgM) specific for hepatitis E virus (HEV) was developed by utilizing well-characterized recombinant protein ET2.1 and its peroxidase-labeled counterpart. Our study showed that the ELISA detected all the positive patient samples (n = 265) regardless of whether they contained IgM or IgG antibodies, or both, while it maintained an excellent specificity of 98.8% with samples from various patient or healthy control groups (total number of samples, 424). The test had a detection limit for anti-HEV IgG antibodies that was equivalent to 62 mIU/ml of the international reference. Compared with the serological status of the specimens determined on the basis of tests performed at the individual collection sites, the testing outcome generated by the new ELISA had a good agreement of 99.3%, with a kappa value of 0.985. The positive predictive value and the negative predictive value for the new test reached 98.1% and 100%, respectively. This ELISA had a positive delta value of 4.836 and a negative delta value of 3.314 (where delta is a measure of the number of standard deviations by which the cutoff is separated from the mean of the sample groups) (N. Crofts, W. Maskill, and I. D. Gust, J. Virol. Methods 22:51-59, 1988), indicating that it had an excellent ability to differentiate the infected and noninfected cohorts. Furthermore, the new design enables the detection of antibodies not only in human samples but also in pig samples. Our preliminary data showed that the ELISA could detect seroconversion in samples from pigs at as early as 14 days postinoculation. The potential utility of detecting specific antibodies in pigs will be an added advantage for managing the disease, with suggested zoonotic implications. PMID:18495846

  20. SENESCENCE-ASSOCIATED DECLINE IN HEPATIC PEROXISOMAL ENZYME ACTIVITIES CORRESPONDS WITH DIMINISHED LEVELS OF RETINOID X RECEPTOR ALPHA, BUT NOT PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR ALPHA1

    EPA Science Inventory

    Abstract

    Aging is associated with alterations in hepatic peroxisomal metabolism and susceptibility to hepatocarcinogenecity produced by agonists of peroxisome proliferator-activated receptor alpha (PPARa). Mechanisms involved in these effects are not well understood. Howev...

  1. Propiconazole increases reactive oxygen species levels in mouse hepatic cells in culture and in mouse liver by a cytochrome P450 enzyme mediated process

    EPA Science Inventory

    Propiconazole induces hepatocarcinomas and hepatoadenomas in mice and is a rat liver tumor promoter. Transcriptional, proteomic, metabolomic and biochemical studies of hepatic tissues from mice treated with propiconazole under the conditions of the chronic bioassay indicate that ...

  2. Viral Hepatitis

    MedlinePlus

    ... Public Home » For Veterans and the Public Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For ... the Public Veterans and Public Home How is Hepatitis C Treated? Find the facts about the newest ...

  3. Pharmacodynamics of dietary phytochemical indoles I3C and DIM: Induction of Nrf2-mediated Phase II drug metabolizing and antioxidant genes and synergism with isothiocyanates

    PubMed Central

    Saw, Constance Lay-Lay; Cintron, Melvilí; Wu, Tien-Yuan; Guo, Yue; Huang, Ying; Jeong, Woo-Sik; Kong, Ah-Ng Tony

    2012-01-01

    The antioxidant response element (ARE) is a critical regulatory element for the expression of many phase II drug metabolizing enzymes (DME), phase III transporters, and anti-oxidant enzymes, mediated by the transcription factor Nrf2. The aim of this study was to examine the potential activation and synergism of Nrf2-ARE-mediated transcriptional activity between four common phytochemicals present in cruciferous vegetables, the indoles; indole-3-carbinol (I3C), 3,3’-diindolylmethane (DIM), and the isothiocyanates (ITCs); phenethyl isothiocyanate (PEITC) and sulforaphane (SFN). The cytotoxicity of the compounds was determined in human liver hepatoma cell line (HepG2-C8). The combination index was calculated to assess the synergistic effects on the induction of ARE-mediated gene expressions. qPCR was employed to measure the mRNA expressions of Nrf2 and Nrf2-mediated genes. I3C and DIM showed less cytotoxicity than SFN and PEITC. Compared to I3C, DIM was found to be a stronger inducer of ARE. Synergism was observed after combined treatments of I3C 6.25 µM + SFN 1 µM, I3C 6.25 µM + PEITC 1 µM and DIM 6.25 µM + PEITC 1 µM, while additive effect was observed for DIM 6.25 µM + SFN 1 µM. Induction of endogenous Nrf2, phase II genes (GSTm2, UGT1A1, and NQO1) and antioxidant genes (HO-1 and SOD1) was also observed. In summary, the indole I3C or DIM alone could induce or syngergistically induce in combination with the ITCs SFN or PEITC, Nrf2-ARE-mediated gene expression, which could potentially enhance cancer chemopreventive activity. PMID:21656528

  4. Viral Hepatitis

    MedlinePlus

    ... with hepatitis? How does a pregnant woman pass hepatitis B virus to her baby? If I have hepatitis B, what does my baby need so that she ... Can I breastfeed my baby if I have hepatitis B? More information on viral hepatitis What is hepatitis? ...

  5. Mass spectrometric QUAL/QUAN approaches for drug metabolism and metabolomics.

    PubMed

    Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard

    2012-01-01

    A liquid chromatography-high-resolution mass spectrometry platform was used for simultaneous qualitative and quantitative (QUAL/QUAN) acquisition, enabling drug metabolism and metabolomics investi- gations. Plasma study samples were monitored for three different groups of patients at a single time-point (1 h after drug administration): one group received acetaminophen (APAP), one group received both APAP and ketorolac and one group was a control group. The quantification of APAP and two of its metabolites (APAP-glucuronide and APAP-cysteine) was performed on a fast acquisition quadrupole-Time-Of-Flight (50-100 ms duty cycle, resolving power of 30,000) compatible with UHPLC time constraints. High-resolution Selected Reaction Monitoring was used for quantification of APAP and its metabolites from 50-10,000 ng/mL using a 50 μL plasma aliquot. Average measured concentrations were for APAP 6,650 ng/mL vs 6,160 ng/mL, APAP-CYS concentrations were 154.2 ng/mL vs 140.6 ng/mL and APAP-GLU concentrations 8,750 ng/mL vs 8,430 ng/mL between the group that received only APAP (n = 11) and the group that received APAP in combination with ketorolac (n = 11). No major differences were observed between the two groups of patients, as it would be expected due to the differing metabolism pathway for both substances. For the qualitative aspect, a metabolomics data processing platform with biological QC samples was applied to the study samples to search for unanticipated metabolites and biomarkers related to APAP and ketorolac metabolism. Multivariate analysis (i.e. Principle Component Analysis), variables grouping tools (i.e. PCVG) and high-resolution MS(/MS) spectra from the MS(ALL) acquisition strategy enabled the profiling and characterization of circulating metabolites of APAP in plasma such as APAP-sulfate, APAP-mercapturate as well as ketorolac. PMID:22613154

  6. Feed-drug interaction of orally applied butyrate and phenobarbital on hepatic cytochrome P450 activity in chickens.

    PubMed

    Mátis, G; Kulcsár, A; Petrilla, J; Hermándy-Berencz, K; Neogrády, Zs

    2016-08-01

    The expression of hepatic drug-metabolizing cytochrome P450 (CYP) enzymes may be affected by several nutrition-derived compounds, such as by the commonly applied feed additive butyrate, possibly leading to feed-drug interactions. The aim of this study was to provide some evidence if butyrate can alter the activity of hepatic CYPs in chickens exposed to CYP-inducing xenobiotics, monitoring for the first time the possibility of such interaction. Ross 308 chickens in the grower phase were treated with daily intracoelomal phenobarbital (PB) injection (80 mg/kg BW), applied as a non-specific CYP-inducer, simultaneously with two different doses of intra-ingluvial sodium butyrate boluses (0.25 and 1.25 g/kg BW) for 5 days. Activity of CYP2H and CYP3A subfamilies was assessed by specific enzyme assays from isolated liver microsomes. According to our results, the lower dose of orally administered butyrate significantly attenuated the PB-triggered elevation of both hepatic CYP2H and CYP3A activities, which might be in association with the partly common signalling pathways of butyrate and CYP-inducing drugs, such as that of PB. Based on these data, butyrate may take part in pharmacoepigenetic interactions with simultaneously applied drugs or other CYP-inducing xenobiotics, with possible consequences for food safety and pharmacotherapy. Butyrate was found to be capable to maintain physiological CYP activity by attenuating CYP induction, underlining the safety of butyrate application in poultry nutrition. PMID:26614344

  7. Difference in the Pharmacokinetics and Hepatic Metabolism of Antidiabetic Drugs in Zucker Diabetic Fatty and Sprague-Dawley Rats.

    PubMed

    Zhou, Xin; Rougée, Luc R A; Bedwell, David W; Cramer, Jeff W; Mohutsky, Michael A; Calvert, Nathan A; Moulton, Richard D; Cassidy, Kenneth C; Yumibe, Nathan P; Adams, Lisa A; Ruterbories, Kenneth J

    2016-08-01

    The Zucker diabetic fatty (ZDF) rat, an inbred strain of obese Zucker fatty rat, develops early onset of insulin resistance and displays hyperglycemia and hyperlipidemia. The phenotypic changes resemble human type 2 diabetes associated with obesity and therefore the strain is used as a pharmacological model for type 2 diabetes. The aim of the current study was to compare the pharmacokinetics and hepatic metabolism in male ZDF and Sprague-Dawley (SD) rats of five antidiabetic drugs that are known to be cleared via various mechanisms. Among the drugs examined, metformin, cleared through renal excretion, and rosiglitazone, metabolized by hepatic cytochrome P450 2C, did not exhibit differences in the plasma clearance in ZDF and SD rats. In contrast, glibenclamide, metabolized by hepatic CYP3A, canagliflozin, metabolized mainly by UDP-glucuronosyltransferases (UGT), and troglitazone, metabolized by sulfotransferase and UGT, exhibited significantly lower plasma clearance in ZDF than in SD rats after a single intravenous administration. To elucidate the mechanisms for the difference in the drug clearance, studies were performed to characterize the activity of hepatic drug-metabolizing enzymes using liver S9 fractions from the two strains. The results revealed that the activity for CYP3A and UGT was decreased in ZDF rats using the probe substrates, and decreased unbound intrinsic clearance in vitro for glibenclamide, canagliflozin, and troglitazone was consistent with lower plasma clearance in vivo. The difference in pharmacokinetics of these two strains may complicate pharmacokinetic/pharmacodynamic correlations, given that ZDF is used as a pharmacological model, and SD rat as the pharmacokinetics and toxicology strain. PMID:27217490

  8. Organic anion transporting polypeptides in the hepatic uptake of PBDE congeners in mice

    SciTech Connect

    Pacyniak, Erik; Hagenbuch, Bruno; The University of Kansas Cancer Center, Kansas City, KS ; Klaassen, Curtis D.; Lehman-McKeeman, Lois; Guo, Grace L.

    2011-11-15

    BDE47, BDE99 and BDE153 are the predominant polybrominated diphenyl ether (PBDE) congeners detected in humans and can induce drug metabolizing enzymes in the liver. We have previously demonstrated that several human liver organic anion transporting polypeptides (humans: OATPs; rodents: Oatps) can transport PBDE congeners. Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. However, the mechanism of the hepatic PBDE uptake in mice is not known. Therefore, the purpose of the current study was to test the hypothesis that BDE47, BDE99, and BDE153 are substrates of mouse hepatic Oatps (Oatp1a1, Oatp1a4, Oatp1b2, and Oatp2b1). We used Human Embryonic Kidney 293 (HEK293) cells transiently expressing individual Oatps and quantified the uptake of BDE47, BDE99, and BDE153. Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners, whereas Oatp1a1 did transport none. Kinetic studies demonstrated that Oatp1a4 and Oatp1b2 transported BDE47 with the greatest affinity, followed by BDE99 and BDE153. In contrast, Oatp2b1 transported all three PBDE congeners with similar affinities. The importance of hepatic Oatps for the liver accumulation of BDE47 was confirmed using Oatp1a4-, and Oatp1b2-null mice. -- Highlights: Black-Right-Pointing-Pointer PBDE congeners are substrates of OATPs expressed in human hepatocytes. Black-Right-Pointing-Pointer Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. Black-Right-Pointing-Pointer Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners in vitro. Black-Right-Pointing-Pointer In vivo Oatp1a4 plays a minor and Oatp1b2 a major role in BDE47 liver accumulation.

  9. Biofabrication of a three-dimensional liver micro-organ as an in vitro drug metabolism model.

    PubMed

    Chang, Robert; Emami, Kamal; Wu, Honglu; Sun, Wei

    2010-12-01

    In their normal in vivo matrix milieu, tissues assume complex well-organized three-dimensional architectures. Therefore, the primary aim in the tissue engineering design process is to fabricate an optimal analog of the in vivo scenario. This challenge can be addressed by applying emerging layered biofabrication approaches in which the precise configuration and composition of cells and bioactive matrix components can recapitulate the well-defined three-dimensional biomimetic microenvironments that promote cell-cell and cell-matrix interactions. Furthermore, the advent of and refinements in microfabricated systems can present physical and chemical cues to cells in a controllable and reproducible fashion unmatched with conventional cultures, resulting in the precise construction of engineered biomimetic microenvironments on the cellular length scale in geometries that are readily parallelized for high throughput in vitro models. As such, the convergence of layered solid freeform fabrication (SFF) technologies along with microfabrication techniques enables the creation of a three-dimensional micro-organ device to serve as an in vitro platform for cell culture, drug screening or to elicit further biological insights, particularly for NASA's interest in a flight-suitable high-fidelity microscale platform to study drug metabolism in space and planetary environments. The proposed model in this paper involves the combinatorial setup of an automated syringe-based, layered direct cell writing bioprinting process with micro-patterning techniques to fabricate a microscale in vitro device housing a chamber of bioprinted three-dimensional liver cell-encapsulated hydrogel-based tissue constructs in defined design patterns that biomimic the cell's natural microenvironment for enhanced biological functionality. In order to assess the structural formability and biological feasibility of such a micro-organ, reproducibly fabricated tissue constructs were biologically characterized for

  10. Alterations in enzymes in an Indian catfish, Clarias batrachus (Linn.), exposed to vanadium

    SciTech Connect

    Chakraborty, A.; Bhattacharjee, S.; Chatterjee, M.

    1995-02-01

    The increase in air and water borne concentrations of vanadium, a physiologically and pharmacologically active substance, has caused renewed interest in the toxicology of this metal. Toxicity studies of vanadium on fish are comparatively scarce. Cytochrome P-450 monoxygenases and conjugating enzymes are important in fish metabolism and elimination of endogenous as well as foreign lipophilic compounds. These enzymes are also known to participate in activation and inactivation of carcinogenic and environmental chemicals. (In vitro) investigations have shown that fish metabolize xenobiotics by mechanisms very similar to those found in mammals. Impairment of drug-metabolizing enzymes is thus deleterious to the organism. Heavy metals are known to influence this group of enzymes. This prompted us to investigate the effect of vanadate, in a dose-responsive and time-dependent manner, on the relative rates and patterns of hepatic glutathione transferase (GST) activity, UDP-glucuronyl transferase (UDPGT) activity and cytochrome P-450 (Cyt P-450) level in an Indian catfish, Clarias batrachus. We chose an aquatic species for our experiment since the environment where aquatic animals live is the main destination of industrial and agricultural wastes. The variations recorded in the level and activity of cytochrome P-450, glutathione transferase and UDP-glu-curonyl transferase are discussed in relation to carcinogenic risk depending on the environment of the fish. In support of the above, petroleum has been found to induce cytochrome P-450 and subsequently produce high levels of neoplasia in fish. Furthermore, GST, UDPGT and Cyt P-450 have been reported as reliable markers for preneoplastic lesions in liver. 21 refs., 3 tabs.

  11. Pigs fed camelina meal increase hepatic gene expression of cytochrome 8b1, aldehyde dehydrogenase, and thiosulfate transferase

    PubMed Central

    2014-01-01

    Camelina sativa is an oil seed crop which can be grown on marginal lands. Camelina seed oil is rich in omega-3 fatty acids (>35%) and γ-tocopherol but is also high in erucic acid and glucosinolates. Camelina meal, is the by-product after the oil has been extracted. Camelina meal was fed to 28 d old weaned pigs at 3.7% and 7.4% until age 56 d. The camelina meal supplements in the soy based diets, improved feed efficiency but also significantly increased the liver weights. Gene expression analyses of the livers, using intra-species microarrays, identified increased expression of phase 1 and phase 2 drug metabolism enzymes. The porcine versions of the enzymes were confirmed by real time PCR. Cytochrome 8b1 (CYP8B1), aldehyde dehydrogenase 2 (Aldh2), and thiosulfate transferase (TST) were all significantly stimulated. Collectively, these genes implicate the camelina glucosinolate metabolite, methyl-sulfinyldecyl isothiocyanate, as the main xeniobiotic, causing increased hepatic metabolism and increased liver weight. PMID:24383433

  12. Pigs fed camelina meal increase hepatic gene expression of cytochrome 8b1, aldehyde dehydrogenase, and thiosulfate transferase.

    PubMed

    Meadus, William Jon; Duff, Pascale; McDonald, Tanya; Caine, William R

    2014-01-01

    Camelina sativa is an oil seed crop which can be grown on marginal lands. Camelina seed oil is rich in omega-3 fatty acids (>35%) and γ-tocopherol but is also high in erucic acid and glucosinolates. Camelina meal, is the by-product after the oil has been extracted. Camelina meal was fed to 28 d old weaned pigs at 3.7% and 7.4% until age 56 d. The camelina meal supplements in the soy based diets, improved feed efficiency but also significantly increased the liver weights. Gene expression analyses of the livers, using intra-species microarrays, identified increased expression of phase 1 and phase 2 drug metabolism enzymes. The porcine versions of the enzymes were confirmed by real time PCR. Cytochrome 8b1 (CYP8B1), aldehyde dehydrogenase 2 (Aldh2), and thiosulfate transferase (TST) were all significantly stimulated. Collectively, these genes implicate the camelina glucosinolate metabolite, methyl-sulfinyldecyl isothiocyanate, as the main xeniobiotic, causing increased hepatic metabolism and increased liver weight. PMID:24383433

  13. Microsome biocolloids for rapid drug metabolism and inhibition assessment by LC-MS

    PubMed Central

    Bajrami, Besnik; Krishnan, Sadagopan; Rusling, James F.

    2012-01-01

    Rat liver microsomes attached to nanoparticles were used for LC-MS studies of CYP3A and 2E1 enzymes in metabolism of N-nitroso compounds. Using these biocolloids, turnover rates were measured within 2 min. Inhibitor IC50 values for ketoconazole (KET) and 4-methylpyrazole (4-MEP) were estimated. PMID:19356087

  14. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

    PubMed Central

    Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

    2016-01-01

    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations. PMID:27312339

  15. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes.

    PubMed

    Davidson, Matthew D; Ballinger, Kimberly R; Khetani, Salman R

    2016-01-01

    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations. PMID:27312339

  16. Activation of CAR and PXR by Dietary, Environmental and Occupational Chemicals Alters Drug Metabolism, Intermediary Metabolism, and Cell Proliferation

    PubMed Central

    Hernandez, J.P.; Mota, L.C.; Baldwin, W.S.

    2010-01-01

    The constitutive androstane receptor (CAR) and the pregnane × receptor (PXR) are activated by a variety of endogenous and exogenous ligands, such as steroid hormones, bile acids, pharmaceuticals, and environmental, dietary, and occupational chemicals. In turn, they induce phase I–III detoxification enzymes and transporters that help eliminate these chemicals. Because many of the chemicals that activate CAR and PXR are environmentally-relevant (dietary and anthropogenic), studies need to address whether these chemicals or mixtures of these chemicals may increase the susceptibility to adverse drug interactions. In addition, CAR and PXR are involved in hepatic proliferation, intermediary metabolism, and protection from cholestasis. Therefore, activation of CAR and PXR may have a wide variety of implications for personalized medicine through physiological effects on metabolism and cell proliferation; some beneficial and others adverse. Identifying the chemicals that activate these promiscuous nuclear receptors and understanding how these chemicals may act in concert will help us predict adverse drug reactions (ADRs), predict cholestasis and steatosis, and regulate intermediary metabolism. This review summarizes the available data on CAR and PXR, including the environmental chemicals that activate these receptors, the genes they control, and the physiological processes that are perturbed or depend on CAR and PXR action. This knowledge contributes to a foundation that will be necessary to discern interindividual differences in the downstream biological pathways regulated by these key nuclear receptors. PMID:20871735

  17. Neonatal activation of the nuclear receptor CAR results in epigenetic memory and permanent change of drug metabolism in mouse liver

    PubMed Central

    Chen, Wei-Dong; Fu, Xianghui; Dong, Bingning; Wang, Yan-Dong; Shiah, Steven; Moore, David D.; Huang, Wendong

    2012-01-01

    Aberrant epigenetic alterations during development may result in long-term epigenetic memory and have a permanent effect on the health of subjects. Constitutive androstane receptor (CAR; NR1I3) is a central regulator of drug/xenobiotic metabolism. Here, we report that transient neonatal activation of CAR results in epigenetic memory and a permanent change of liver drug metabolism. CAR activation by neonatal exposure to a CAR-specific ligand, 1,4-bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) led to persistently induced expression of the CAR target genes Cyp2B10 and Cyp2C37 throughout the life of exposed mice. These mice showed a permanent reduction in sensitivity to zoxazolamine treatment as adults. Compared with control groups, the induction of Cyp2B10 and Cyp2C37 in hepatocytes isolated from these mice was more sensitive to low concentrations of the CAR agonist TCPOBOP. Accordingly, neonatal activation of CAR led to a permanent increase of histone 3 lysine 4 (H3K4) mono-, di- and trimethylation and decrease of H3K9 trimethylation within the Cyp2B10 locus. Transcriptional coactivator ASC-2 and histone demethylase JMJD2d participated in this CAR-dependent epigenetic switch. Conclusion Neonatal activation of CAR results in epigenetic memory and a permanent change of liver drug metabolism. PMID:22488010

  18. Highly efficient gene transfer into hepatocyte-like HepaRG cells: new means for drug metabolism and toxicity studies.

    PubMed

    Laurent, Veronique; Fraix, Aurore; Montier, Tristan; Cammas-Marion, Sandrine; Ribault, Catherine; Benvegnu, Thierry; Jaffres, Paul-Alain; Loyer, Pascal

    2010-03-01

    HepaRG progenitor cells are capable of differentiating into hepatocyte-like cells that express a large set of liver-specific functions. These cells, however, only express small amounts of an important cytochrome P450, the CYP2E1, which limits their use for toxicological studies of drugs metabolized by this pathway. Our aim was to establish an efficient transfection protocol to increase CYP2E1 expression in HepaRG cells. Transfection protocols of the green fluorescent protein (GFP) reporter gene were evaluated using electroporation and cationic lipids belonging to the lipophosphonates, lipophosphoramidates and lipids derived from glycine betaine. Following optimization of the charge ratios, plasmid DNA and formulations with neutral co-lipids, the lipophosphoramidate compounds KLN47 and BSV10, allowed expression of the GFP in approximately 50% of adherent progenitor HepaRG cells, while electroporation targeted GFP expression in approximately 85% of both progenitor and differentiated cells in suspension. Transient enforced expression of active CYP2E1 was also achieved in progenitors and/or differentiated HepaRG cells using the electroporation and the lipophosphoramidate compound BSV10. Importantly, in electroporated cells, CYP2E1 expression level was correlated with a significant increase in CYP2E1-specific enzymatic activity, which opens new perspectives for this CYP-dependent drug metabolism and toxicity studies using HepaRG cells. PMID:20213646

  19. Development of an on-animal separation-based sensor for monitoring drug metabolism in freely roaming sheep.

    PubMed

    Scott, David E; Willis, Sean D; Gabbert, Seth; Johnson, David; Naylor, Erik; Janle, Elsa M; Krichevsky, Janice E; Lunte, Craig E; Lunte, Susan M

    2015-06-01

    The development of an on-animal separation-based sensor that can be employed for monitoring drug metabolism in a freely roaming sheep is described. The system consists of microdialysis sampling coupled to microchip electrophoresis with electrochemical detection (MD-ME-EC). Separations were accomplished using an all-glass chip with integrated platinum working and reference electrodes. Discrete samples from the microdialysis flow were introduced into the electrophoresis chip using a flow-gated injection approach. Electrochemical detection was accomplished in-channel using a two-electrode isolated potentiostat. Nitrite was separated by microchip electrophoresis using reverse polarity and a run buffer consisting of 50 mM phosphate at pH 7.4. The entire system was under telemetry control. The system was first tested with rats to monitor the production of nitrite following perfusion of nitroglycerin into the subdermal tissue using a linear probe. The data acquired using the on-line MD-ME-EC system were compared to those obtained by off-line analysis using liquid chromatography with electrochemical detection (LC-EC), using a second microdialysis probe implanted parallel to the first probe in the same animal. The MD-ME-EC device was then used on-animal to monitor the subdermal metabolism of nitroglycerin in sheep. The ultimate goal is to use this device to simultaneously monitor drug metabolism and behavior in a freely roaming animal. PMID:25697221

  20. Quantum Mechanics/Molecular Mechanics Modeling of Drug Metabolism: Mexiletine N-Hydroxylation by Cytochrome P450 1A2.

    PubMed

    Lonsdale, Richard; Fort, Rachel M; Rydberg, Patrik; Harvey, Jeremy N; Mulholland, Adrian J

    2016-06-20

    The mechanism of cytochrome P450(CYP)-catalyzed hydroxylation of primary amines is currently unclear and is relevant to drug metabolism; previous small model calculations have suggested two possible mechanisms: direct N-oxidation and H-abstraction/rebound. We have modeled the N-hydroxylation of (R)-mexiletine in CYP1A2 with hybrid quantum mechanics/molecular mechanics (QM/MM) methods, providing a more detailed and realistic model. Multiple reaction barriers have been calculated at the QM(B3LYP-D)/MM(CHARMM27) level for the direct N-oxidation and H-abstraction/rebound mechanisms. Our calculated barriers indicate that the direct N-oxidation mechanism is preferred and proceeds via the doublet spin state of Compound I. Molecular dynamics simulations indicate that the presence of an ordered water molecule in the active site assists in the binding of mexiletine in the active site, but this is not a prerequisite for reaction via either mechanism. Several active site residues play a role in the binding of mexiletine in the active site, including Thr124 and Phe226. This work reveals key details of the N-hydroxylation of mexiletine and further demonstrates that mechanistic studies using QM/MM methods are useful for understanding drug metabolism. PMID:27064685

  1. Rational prescription of drugs within similar therapeutic or structural class for gastrointestinal disease treatment: Drug metabolism and its related interactions

    PubMed Central

    Zhou, Quan; Yan, Xiao-Feng; Zhang, Zhong-Miao; Pan, Wen-Sheng; Zeng, Su

    2007-01-01

    AIM: To review and summarize drug metabolism and its related interactions in prescribing drugs within the similar therapeutic or structural class for gastrointestinal disease treatment so as to promote rational use of medicines in clinical practice. METHODS: Relevant literature was identified by performing MEDLINE/Pubmed searches covering the period from 1988 to 2006. RESULTS: Seven classes of drugs were chosen, including gastric proton pump inhibitors, histamine H2-receptor antagonists, benzamide-type gastroprokinetic agents, selective 5-HT3 receptor antagonists, fluoroquinolones, macrolide antibiotics and azole antifungals. They showed significant differences in metabolic profile (i.e., the fraction of drug metabolized by cytochrome P450 (CYP), CYP reaction phenotype, impact of CYP genotype on interindividual pharmacokinetics variability and CYP-mediated drug-drug interaction potential). Many events of severe adverse drug reactions and treatment failures were closely related to the ignorance of the above issues. CONCLUSION: Clinicians should acquaint themselves with what kind of drug has less interpatient variability in clearance and whether to perform CYP genotyping prior to initiation of therapy. The relevant CYP knowledge helps clinicians to enhance the management of patients with gastrointestinal disease who may require treatment with polytherapeutic regimens. PMID:17948937

  2. Development of an On-animal Separation-based Sensor for Monitoring Drug Metabolism in Freely Roaming Sheep

    PubMed Central

    Scott, David E.; Willis, Sean D.; Gabbert, Seth; Johnson, Dave A.; Naylor, Erik; Janle, Elsa M.; Krichevsky, Janice E.; Lunte, Craig E.; Lunte, Susan M.

    2015-01-01

    The development of an on-animal separation-based sensor that can be employed for monitoring drug metabolism in a freely roaming sheep is described. The system consists of microdialysis sampling coupled directly to microchip electrophoresis with electrochemical detection (MD-ME-EC). Separations were accomplished using an all-glass chip with integrated platinum working and reference electrodes. Discrete samples from the microdialysis flow were introduced into the electrophoresis chip using a flow-gated injection approach. Electrochemical detection was accomplished in-channel using a two-electrode isolated potentiostat. Nitrite was separated by microchip electrophoresis using reverse polarity and a run buffer consisting of 50 mM phosphate at pH 7.4. The entire system was under telemetry control. The system was first tested with rats to monitor the production of nitrite following introduction of nitroglycerin into the subdermal tissue using a linear probe. The data acquired using the on-line MD-ME-EC system was compared to that obtained off-line analysis by liquid chromatography with electrochemical detection (LC-EC), using a second microdialysis probe implanted parallel to the first probe in the same animal. The MD-ME-EC device was then used on-animal to monitor the subdermal metabolism of nitroglycerin in sheep. The ultimate goal is to use this device to simultaneously monitor drug metabolism and behavior in a freely roaming animal. PMID:25697221

  3. Coordinating Role of RXRα in Downregulating Hepatic Detoxification during Inflammation Revealed by Fuzzy-Logic Modeling.

    PubMed

    Keller, Roland; Klein, Marcus; Thomas, Maria; Dräger, Andreas; Metzger, Ute; Templin, Markus F; Joos, Thomas O; Thasler, Wolfgang E; Zell, Andreas; Zanger, Ulrich M

    2016-01-01

    During various inflammatory processes circulating cytokines including IL-6, IL-1β, and TNFα elicit a broad and clinically relevant impairment of hepatic detoxification that is based on the simultaneous downregulation of many drug metabolizing enzymes and transporter genes. To address the question whether a common mechanism is involved we treated human primary hepatocytes with IL-6, the major mediator of the acute phase response in liver, and characterized acute phase and detoxification responses in quantitative gene expression and (phospho-)proteomics data sets. Selective inhibitors were used to disentangle the roles of JAK/STAT, MAPK, and PI3K signaling pathways. A prior knowledge-based fuzzy logic model comprising signal transduction and gene regulation was established and trained with perturbation-derived gene expression data from five hepatocyte donors. Our model suggests a greater role of MAPK/PI3K compared to JAK/STAT with the orphan nuclear receptor RXRα playing a central role in mediating transcriptional downregulation. Validation experiments revealed a striking similarity of RXRα gene silencing versus IL-6 induced negative gene regulation (rs = 0.79; P<0.0001). These results concur with RXRα functioning as obligatory heterodimerization partner for several nuclear receptors that regulate drug and lipid metabolism. PMID:26727233

  4. Coordinating Role of RXRα in Downregulating Hepatic Detoxification during Inflammation Revealed by Fuzzy-Logic Modeling

    PubMed Central

    Thomas, Maria; Dräger, Andreas; Metzger, Ute; Templin, Markus F.; Joos, Thomas O.; Thasler, Wolfgang E.; Zell, Andreas; Zanger, Ulrich M.

    2016-01-01

    During various inflammatory processes circulating cytokines including IL-6, IL-1β, and TNFα elicit a broad and clinically relevant impairment of hepatic detoxification that is based on the simultaneous downregulation of many drug metabolizing enzymes and transporter genes. To address the question whether a common mechanism is involved we treated human primary hepatocytes with IL-6, the major mediator of the acute phase response in liver, and characterized acute phase and detoxification responses in quantitative gene expression and (phospho-)proteomics data sets. Selective inhibitors were used to disentangle the roles of JAK/STAT, MAPK, and PI3K signaling pathways. A prior knowledge-based fuzzy logic model comprising signal transduction and gene regulation was established and trained with perturbation-derived gene expression data from five hepatocyte donors. Our model suggests a greater role of MAPK/PI3K compared to JAK/STAT with the orphan nuclear receptor RXRα playing a central role in mediating transcriptional downregulation. Validation experiments revealed a striking similarity of RXRα gene silencing versus IL-6 induced negative gene regulation (rs = 0.79; P<0.0001). These results concur with RXRα functioning as obligatory heterodimerization partner for several nuclear receptors that regulate drug and lipid metabolism. PMID:26727233

  5. Influence of liver disease and environmental factors on hepatic monooxygenase activity in vitro.

    PubMed

    Brodie, M J; Boobis, A R; Bulpitt, C J; Davies, D S

    1981-01-01

    The effects of liver disease and environmental factors on hepatic microsomal cytochrome P-450 content, NADPH-cytochrome c reductase (reductase) activity and aryl hydrocarbon hydroxylase (AHH) activity have been simultaneously investigated in 70 patients undergoing diagnostic liver biopsy. The activity of reductase was not significantly affected by the presence of liver disease or any of the environmental factors studied. Cytochrome P-450 content decreased with increasing severity of liver disease whereas AHH activity was only significantly reduced in biopsies showing hepatocellular destruction. None of the parameters of monooxygenase activity varied significantly with the age or sex of the patients. Alcohol excess was associated with decreased cytochrome P-450 content and AHH activity and this effect was independent of the histological status of the biopsy. Both high caffeine intake and cigarette smoking increased AHH activity in the absence of any change in cytochrome P-450 content. There was a positive correlation between the number of meat meals eaten per week and cytochrome P-450 content. Chronic treatment with enzyme-inducing anticonvulsants appeared to increase both cytochrome P-450 content and AHH activity. Despite differential effects of liver disease and environmental influences on cytochrome P-450 content and AHH activity there was a highly significant correlation between the two parameters. The results of the present study correlate well with the known effects of disease and environment on drug metabolism in vivo. PMID:7308271

  6. Modulatory potential of smokeless tobacco on the garlic, mace or black mustard-altered hepatic detoxication system enzymes, sulfhydryl content and lipid peroxidation in murine system.

    PubMed

    Singh, A; Singh, S P

    1997-09-16

    The present study evaluates the potential of smokeless tobacco to modify the chemopreventive efficacy of minor dietary constituents, including garlic, mace or black mustard, via modulating the competing pathways of hepatic detoxication system and antioxidant defense mechanism in murine system. Garlic (100 mg/kg b.w. per day) by gavage and mace (1% w/w) or black mustard (1% w/w) in diet induced a significant increase in the levels of glutathione-S-transferase (GST), acid-soluble sulfhydryl (-SH), cytochrome b5 (Cyt.b5) and cytochrome P-450 (Cyt.P-450) in murine liver. The hepatic levels of GST and -SH were significantly depressed whereas microsomal Cyt.b5, Cyt.P-450 and MDA levels were elevated in groups treated with smokeless tobacco (50 or 100 mg/kg b.w. per day). The data revealed the inhibitory potential of smokeless tobacco on garlic-induced hepatic GST/GSH system besides the significant augmentation by smokeless tobacco on garlic or mace or black mustard-induced microsomal cytochromes. The possible implications of modulation in competing bioactivation and detoxication pathways in the process of chemical carcinogenesis are discussed. PMID:9310267

  7. Multiple plasma enzyme activities in liver disease

    PubMed Central

    Hargreaves, T.; Janota, I.; Smith, M. J. H.

    1961-01-01

    The measurement of the plasma activities of glutamic-oxaloacetic and glutamic-pyruvic transaminases, aldolase, cholinesterase, and isocitric, lactic, and phosphogluconic dehydrogenases in random samples of blood was found to be of no value in the differential diagnosis of hepatitis, obstructive jaundice, hepatic cirrhosis, and neoplastic conditions involving the liver. Serial determinations of the enzyme activities provided useful information about the course of certain hepatic disorders, particularly acute viral hepatitis. PMID:13711559

  8. Effect of SPG/indomethacin treatment on sepsis, interleukin-6 production, and expression of hepatic cytochrome P450 isoforms in differing strains of mice.

    PubMed

    Saito, Maki; Nameda, Sachiko; Miura, Noriko N; Adachi, Yoshiyuki; Ohno, Naohito

    2009-03-01

    We previously reported that a combination of beta-glucan and indomethacin (IND), a non-steroidal anti-inflammatory drug, was lethal to mice. This lethality was strongly related to translocation of enterobacterial flora to various organs and the development of a systemic inflammation. In this study, we examined expression of microsomal cytochrome P450 (CYP), a drug-metabolizing enzyme mostly found in the liver. Normal ICR mice and endotoxin-low responder C3H/HeJ mice were employed to assess effects of endotoxin on impairment of CYP. In the ICR mice, CYP3A11 expression was decreased by beta-glucan or IND. In the early stage of beta-glucan + IND-treatment, 3A11 expression decreased more significantly; when shock was induced, CYP was dramatically decreased. 3A11 expression was also decreased in C3H/HeJ mice, but the effect was milder. In contrast, in both strains, CYP2E1 expression did not vary due to beta-glucan or IND, but decreased during sepsis. To clarify the molecular mechanisms of induced sepsis in C3H/HeJ mice, the reactivity of other pathogen-associated molecular patterns (PAMPs) was assessed. Those studies showed cooperative effects between Pam(3)CSK(4) (Pam(3)) and CpG ODN (CpG-oligodeoxynucleotide) on the induction of IL-6 synthesis by C3H/HeJ spleen cells. The findings here suggest that the beta-glucan + IND combination influenced hepatic cytochrome P450 expression, particularly in the late stage of sepsis. The results also indicate that this change may be associated with not only endotoxin but other PAMPs as well, and could be affected by the integrity of a host's drug metabolism function. PMID:19519162

  9. The Aldo-Keto Reductase Superfamily and its Role in Drug Metabolism and Detoxification

    PubMed Central

    Barski, Oleg A.; Tipparaju, Srinivas M.; Bhatnagar, Aruni

    2008-01-01

    The Aldo-Keto Reductase (AKR) superfamily comprises of several enzymes that catalyze redox transformations involved in biosynthesis, intermediary metabolism and detoxification. Substrates of the family include glucose, steroids, glycosylation end products, lipid peroxidation products, and environmental pollutants. These proteins adopt a (β/α)8 barrel structural motif interrupted by a number of extraneous loops and helixes that vary between proteins and bring structural identity to individual families. The human AKR family differs from the rodent families. Due to their broad substrate specificity, AKRs play an important role in the Phase II detoxification of a large number of pharmaceuticals, drugs, and xenobiotics. PMID:18949601

  10. Human hereditary hepatic porphyrias.

    PubMed

    Nordmann, Yves; Puy, Hervé

    2002-11-01

    The human hereditary hepatic porphyrias are diseases due to marked deficiencies of enzymes in the heme biosynthetic pathway. Porphyrias can be classified as either hepatic or erythroid, depending on the major production site of porphyrins or their precursors. The pathogenesis of inherited hepatic porphyrias has now been defined at the molecular level. Some gene carriers are vulnerable to a range of exogenous and endogenous factors, which may trigger neuropsychiatric and/or cutaneous symptoms. Early diagnosis is of prime importance since it makes way for counselling. In this article we present an overview of recent advances on hepatic porphyrias: 5-aminolevulinic acid dehydratase deficiency porphyria, acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT), hereditary coproporphyria (HC), and variegate porphyria (VP). PMID:12367763

  11. Hepatitis virus panel

    MedlinePlus

    Hepatitis A antibody test; Hepatitis B antibody test; Hepatitis C antibody test; Hepatitis D antibody test ... or past infection, or immunity to hepatitis A Hepatitis B tests: Hepatitis B surface antigen (HBsAg), you have ...

  12. Hepatitis C and HIV

    MedlinePlus

    ... Problems : Hepatitis C Subscribe Translate Text Size Print Hepatitis C What is Hepatitis? Hepatitis means inflammation of the liver. This condition ... our related pages, Hepatitis A and Hepatitis B . Hepatitis C and HIV About 25% of people living ...

  13. Hepatitis B and HIV

    MedlinePlus

    ... Problems : Hepatitis B Subscribe Translate Text Size Print Hepatitis B What is Hepatitis? Hepatitis means inflammation of the liver. This condition ... our related pages, Hepatitis A and Hepatitis C . Hepatitis B and HIV About 10% of people living ...

  14. Protective Effect of Free and Bound Polyphenol Extracts from Ginger (Zingiber officinale Roscoe) on the Hepatic Antioxidant and Some Carbohydrate Metabolizing Enzymes of Streptozotocin-Induced Diabetic Rats

    PubMed Central

    Kazeem, Mutiu Idowu; Akanji, Musbau Adewunmi; Yakubu, Musa Toyin; Ashafa, Anofi Omotayo Tom

    2013-01-01

    This study investigated the hepatoprotective effects of polyphenols from Zingiber officinale on streptozotocin-induced diabetic rats by assessing liver antioxidant enzymes, carbohydrate-metabolizing enzymes and liver function indices. Initial oral glucose tolerance test was conducted using 125 mg/kg, 250 mg/kg, and 500 mg/kg body weight of both free and bound polyphenols from Z. officinale. 28 day daily oral administration of 500 mg/kg body weight of free and bound polyphenols from Z. officinale to streptozotocin-induced (50 mg/kg) diabetic rats significantly reduced (P < 0.05) the fasting blood glucose compared to control groups. There was significant increase (P < 0.05) in the antioxidant enzymes activities in the animals treated with both polyphenols. Similarly, the polyphenols normalised the activities of some carbohydrate metabolic enzymes (hexokinase and phosphofructokinase) in the liver of the rats treated with it and significantly reduced (P < 0.05) the activities of liver function enzymes. The results from the present study have shown that both free and bound polyphenols from Z. officinale especially the free polyphenol could ameliorate liver disorders caused by diabetes mellitus in rats. This further validates the use of this species as medicinal herb and spice by the larger population of Nigerians. PMID:24367390

  15. Ephedra water decoction and cough tablets containing ephedra and liquorice induce CYP1A2 but not CYP2E1 hepatic enzymes in rats.

    PubMed

    Tang, Jingling; Ji, Hongyu; Shi, Jing; Wu, Linhua

    2016-01-01

    1. Ephedra water decoction (EWD) and cough tablets containing ephedra and liquorice (maxing cough tablets, MXCT) have been widely used in the treatment of asthma. In the clinic, EWD and MXCT may be prescribed with theophylline, one of the most popular antiasthmatic drugs. CYP1A2 and CYP2E1 are mainly involved in the oxidative metabolism of theophylline in human liver. Drug interactions involving the cytochrome P450 (CYP) isoforms generally are of two types: enzyme induction or enzyme inhibition. Enzyme inhibition reduces metabolism, whereas induction can increase it. 2. To evaluate the pretreatment effect of EWD and MXCT on CYP1A2 and CYP2E1, CYP1A2 and CYP2E1 activity, the protein expression and mRNA expression levels were determined. After pretreatment with EWD or MXCT, the enzyme activity, mRNA expression and protein expression of CYP1A2 were increased significantly (p < 0.05), but enzyme activity of CYP2E1 did not change compared with the control. 3. It was demonstrated that EWD or MXCT pretreatment obviously induced CYP1A2, therefore, in patients taking EWD or MXCT, possible CYP-induced drug interaction should be noted to decrease the risk of therapeutic failure or adverse effects resulting from the use of additional therapeutic agents. PMID:26153439

  16. Development of an enzyme-linked immunosorbent assay analytical platform for refolding yield determination of recombinant hepatitis B virus X (HBx) protein.

    PubMed

    Basu, Anindya; Leong, Susanna Su Jan

    2011-11-01

    We report the development of a novel ELISA platform to quantitate hepatitis B virus X (HBx) protein refolding yields, which is critical for rational design and scaleup of aHBx bioprocess. HBx refolding yields were measured by determining the amount of HBx bound to immobilized GST-p53 on a "reduced glutathione"-functionalized maleimide surface. Refolding yields were distinguished from soluble yields, which were determined by measuring total HBx protein bound to a maleimide surface under reducing conditions. This platform is amenable to scaleup, and will expedite HBx production for structural and clinical studies, leading to the development of HBx-based therapy for liver cancer. PMID:21806960

  17. Hepatitis Testing

    MedlinePlus

    ... caused by viruses. They include hepatitis A, hepatitis B, and hepatitis C. To diagnose hepatitis, your health care provider will ask you about your medical history and symptoms, do a physical exam, and order blood tests. There are blood tests for each type of ...

  18. Meta-analysis of hepatic cytochrome P450 ontogeny to underwrite the prediction of pediatric pharmacokinetics using physiologically based pharmacokinetic modeling.

    PubMed

    Upreti, Vijay V; Wahlstrom, Jan L

    2016-03-01

    The accurate prediction of pharmacokinetics (PK) is fundamental to underwriting safety and efficacy in pediatric clinical trials; age-dependent PK may be observed with pediatrics because of the growth and maturation processes that occur during development. Understanding the ontogeny of drug-metabolizing enzymes is a critical enabler for pediatric PK prediction, as enzyme expression or activity may change with age. Although ontogeny functions for the cytochrome P450s (CYPs) have been developed, disconnects between ontogeny functions for the same CYP may exist, depending on whether the functions were derived from in vitro or in vivo data. This report describes the development of ontogeny functions for all the major hepatic CYPs based on in vitro or in vivo data; these ontogeny functions were subsequently incorporated into a physiologically based pharmacokinetic model and evaluated. Pediatric PK predictions based on in vivo-derived ontogeny functions performed markedly better than those developed from in vitro data for intravenous (100% versus 51% within 2-fold, respectively) and oral (98% versus 67%, respectively) dosing. The verified models were then applied to complex pediatric scenarios involving active metabolites, CYP polymorphisms and physiological changes because of critical illness; the models reasonably explained the observed age-dependent changes in pediatric PK. PMID:26139104

  19. Expression of Enzymes that Metabolize Medications

    NASA Technical Reports Server (NTRS)

    Wotring, Virginia E.; Peters, C. P.

    2012-01-01

    Most pharmaceuticals are metabolized by the liver. Clinically-used medication doses are given with normal liver function in mind. A drug overdose can result if the liver is damaged and removing pharmaceuticals from the circulation at a rate slower than normal. Alternatively, if liver function is elevated and removing drugs from the system more quickly than usual, it would be as if too little drug had been given for effective treatment. Because of the importance of the liver in drug metabolism we want to understand the effects of spaceflight on the enzymes of the liver.

  20. A decision tree approach for the application of drug metabolism and kinetic studies to in vivo and in vitro toxicological and pharmacological testing.

    PubMed

    Bach, P H; Bridges, J W

    1985-01-01

    The integration of toxicological and other biological findings with information on drug metabolism and pharmacokinetics is often very important for rational decision making in safety evaluation programmes. This goal is unlikely to be achieved by conducting a routine package of inflexibly defined drug metabolism and pharmacokinetic test protocols for each new chemical. Rather, an intelligent selection of experiments based on the known properties of a chemical is required. A series of decision trees are proposed which serve as an aide memoire in the choice of appropriate drug metabolism and pharmacokinetic experiments. These decision trees cover the physicochemical properties of a chemical, data on animal and human pharmacology and toxicology, and environmental information relevant to possible contamination. In many cases, drug metabolism and pharmacokinetic factors are an important prerequisite to the design of in vitro tests that are relevant to the in vivo situation. A scheme is provided to assist the identification of appropriate conditions for the in vitro testing of individual chemicals. PMID:3868347

  1. The impact of skin viability on drug metabolism and permeation -- BSA toxicity on primary keratinocytes.

    PubMed

    Haberland, A; Schreiber, S; Maia, C Santos; Rübbelke, M K; Schaller, M; Korting, H C; Kleuser, B; Schimke, I; Schäfer-Korting, M

    2006-04-01

    For testing cutaneous absorption of drugs, ingredients of cosmetics and also for risk assessment of industrial compounds predictable in vitro test protocols are under investigation using excised skin or reconstructed human epidermis. Since the metabolizing enzymes expressed by viable skin can influence the absorption behaviour of substances by changing their structure and thereby their physicochemical characteristics, the metabolic capacity should be considered in the design of the test protocols of compounds susceptible to metabolism. Then data, generated using viable reconstructed epidermis may reflect the in vivo situation. Interestingly, bovine serum albumin (BSA) commonly used in receptor media in permeation studies to facilitate solubility of highly lipophilic substances strongly inhibited the metabolism of topically applied prednicarbate in reconstructed epidermis. Here, we show that 5% BSA is toxic to reconstructed epidermis and keratinocytes which was consistent with the earlier findings. While media toxicity (deficiency media) was at least partly the cause of both apoptotic and necrotic processes in keratinocytes, BSA only slightly increased the rate of necrotic cells. Moreover, caspase inhibitors did not reduce BSA toxicity. Yet, the results show that BSA toxicity on keratinocytes has to be carefully considered if this protein is used in permeation studies with reconstructed epidermis. PMID:16182510

  2. Telmisartan prevents hepatic fibrosis and enzyme-altered lesions in liver cirrhosis rat induced by a choline-deficient L-amino acid-defined diet

    SciTech Connect

    Jin Haiyan; Yamamoto, Naoki; Uchida, Koichi; Terai, Shuji; Sakaida, Isao

    2007-12-28

    Rennin-angiotensin system is involved in liver fibrogenesis through activating hepatic stellate cells (HSCs). Telmisartan (Tel) is an angiotensin II type 1 receptor antagonist, could function as a selective peroxisome proliferator-activated receptor {gamma} activator. Here we studied the effect of Tel on liver fibrosis, pre-neoplastic lesions in vivo and primary HSCs in vitro. In vivo study, we used the choline-deficient L-amino acid-defined (CDAA)-diet induced rat NASH model. The rats were fed the CDAA diet for 8 weeks to induce liver fibrosis and pre-neoplastic lesions, and then co-administrated with Tel for another 10 weeks. Tel prevented liver fibrogenesis and pre-neoplastic lesions by down-regulating TGF{beta}1 and TIMP-1, 2 and increasing MMP-13 expression. Tel inhibited HSCs activation and proliferation. These results suggested that Tel could be a promising drug for NASH related liver fibrosis.

  3. Effects of ursodeoxycholic acid on serum liver enzymes and bile acid metabolism in chronic active hepatitis: a dose-response study.

    PubMed

    Crosignani, A; Battezzati, P M; Setchell, K D; Camisasca, M; Bertolini, E; Roda, A; Zuin, M; Podda, M

    1991-02-01

    The effect of ursodeoxycholic acid administration on liver function tests and on bile acid metabolism was investigated in 18 patients with chronic active hepatitis. Three different doses of ursodeoxycholic acid--250 mg, 500 mg and 750 mg--were administered daily to each patient for consecutive 2-mo periods. The order of doses was randomly assigned according to a replicated Latin-square design. A significant decrease in serum transaminases and gamma-glutamyl transpeptidase occurred with the lowest dose of ursodeoxycholic acid, which corresponded to 4 mg/kg body wt/day, and no further significant decrease with the higher doses was seen. Biliary bile acid composition was determined by high-performance liquid chromatography and gas chromatography-mass spectrometry. At entry the relative proportions of major bile acids were similar to those observed in normal individuals. During treatment the mean percentage of ursodeoxycholic acid in bile (22% with the 250 mg dose, 32% with the 500 mg dose and 34% with the 750 mg dose) was lower than values previously reported for patients with gallstones and normal liver function. The major bile acids were cholic, chenodeoxycholic and deoxycholic acids. A number of unusual bile acids were identified by gas chromatography-mass spectrometry, but these accounted for only 3% to 5% of the total and did not change during ursodeoxycholic acid therapy. No correlation between the improvement in liver function tests and the percentage of ursodeoxycholic acid in bile existed. These data suggest that even a slight enrichment of bile with ursodeoxycholic acid, as is attained with 250 mg/day, is effective in improving biochemical markers of liver function in patients with chronic active hepatitis. PMID:1671665

  4. Absolute protein quantification of clinically relevant cytochrome P450 enzymes and UDP-glucuronosyltransferases by mass spectrometry-based targeted proteomics.

    PubMed

    Gröer, C; Busch, D; Patrzyk, M; Beyer, K; Busemann, A; Heidecke, C D; Drozdzik, M; Siegmund, W; Oswald, S

    2014-11-01

    Cytochrome P450 (CYP) enzymes and UDP-glucuronosyltransferases (UGT) are major determinants in the pharmacokinetics of most drugs on the market. To investigate their impact on intestinal and hepatic drug metabolism, we developed and validated quantification methods for nine CYP (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP3A5) and four UGT enzymes (UGT1A1, UGT1A3, UGT2B7 and UGT2B15) that have been shown to be of clinical relevance in human drug metabolism. Protein quantification was performed by targeted proteomics using liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based determination of enzyme specific peptides after tryptic digestion using in each case stable isotope labelled peptides as internal standard. The chromatography of the respective peptides was performed with gradient elution using a reversed phase (C18) column (Ascentis(®) Express Peptide ES-C18, 100mm×2.1mm, 2.7μm) and 0.1% formic acid (FA) as well as acetonitrile with 0.1% FA as mobile phases at a flow rate of 300μl/min. The MS/MS detection of all peptides was done simultaneously with a scheduled multiple reaction monitoring (MRM) method in the positive mode by monitoring in each case three mass transitions per proteospecific peptide and the internal standard. The assays were validated according to current bioanalytical guidelines with respect to specificity, linearity (0.25-50nM), within-day and between-day accuracy and precision, digestion efficiency as well as stability. Finally, the developed method was successfully applied to determine the CYP and UGT protein amount in human liver and intestinal microsomes. The method was shown to possess sufficient specificity, sensitivity, accuracy, precision and stability to quantify clinically relevant human CYP and UGT enzymes. PMID:25218440

  5. Application of chimeric mice with humanized liver for study of human-specific drug metabolism.

    PubMed

    Bateman, Thomas J; Reddy, Vijay G B; Kakuni, Masakazu; Morikawa, Yoshio; Kumar, Sanjeev

    2014-06-01

    Human-specific or disproportionately abundant human metabolites of drug candidates that are not adequately formed and qualified in preclinical safety assessment species pose an important drug development challenge. Furthermore, the overall metabolic profile of drug candidates in humans is an important determinant of their drug-drug interaction susceptibility. These risks can be effectively assessed and/or mitigated if human metabolic profile of the drug candidate could reliably be determined in early development. However, currently available in vitro human models (e.g., liver microsomes, hepatocytes) are often inadequate in this regard. Furthermore, the conduct of definitive radiolabeled human ADME studies is an expensive and time-consuming endeavor that is more suited for later in development when the risk of failure has been reduced. We evaluated a recently developed chimeric mouse model with humanized liver on uPA/SCID background for its ability to predict human disposition of four model drugs (lamotrigine, diclofenac, MRK-A, and propafenone) that are known to exhibit human-specific metabolism. The results from these studies demonstrate that chimeric mice were able to reproduce the human-specific metabolite profile for lamotrigine, diclofenac, and MRK-A. In the case of propafenone, however, the human-specific metabolism was not detected as a predominant pathway, and the metabolite profiles in native and humanized mice were similar; this was attributed to the presence of residual highly active propafenone-metabolizing mouse enzymes in chimeric mice. Overall, the data indicate that the chimeric mice with humanized liver have the potential to be a useful tool for the prediction of human-specific metabolism of xenobiotics and warrant further investigation. PMID:24700822

  6. Hepatitis B and Hepatitis C in Pregnancy

    MedlinePlus

    ... infected with the hepatitis B virus, can I breastfeed? • If I am infected with the hepatitis B ... infected with the hepatitis C virus, can I breastfeed? • Glossary What are hepatitis B and hepatitis C ...

  7. Contributions of Human Enzymes in Carcinogen Metabolism

    PubMed Central

    Rendic, Slobodan; Guengerich, F. Peter

    2012-01-01

    Considerable support exists for roles of metabolism in modulating the carcinogenic properties of chemicals. In particular, many of these compounds are procarcinogens that require activation to electrophilic forms to exert genotoxic effects. We systematically analyzed the existing literature on metabolism of carcinogens by human enzymes, which has been developed largely in the past 25 years. The metabolism and especially bioactivation of carcinogens are dominated by cytochrome P450 enzymes (66% of bioactivations). Within this group, six P450s—1A1, 1A2, 1B1, 2A6, 2E1, and 3A4—accounted for 77% of the P450 activation reactions. The roles of these P450s can be compared with those estimated for drug metabolism and should be considered in issues involving enzyme induction, chemoprevention, molecular epidemiology, inter-individual variations, and risk assessment. PMID:22531028

  8. Hepatitis virus panel

    MedlinePlus

    Hepatitis A antibody test; Hepatitis B antibody test; Hepatitis C antibody test; Hepatitis D antibody test ... There are different tests for hepatitis A and B. A positive test is ... may mean: You currently have a hepatitis infection. This may ...

  9. Hepatitis C and Incarceration

    MedlinePlus

    HEPATITIS C & INCARCERATION What is hepatitis? “Hepatitis” means inflammation or swelling of the liver. The liver is an important ... viral hepatitis: Hepatitis A, Hepatitis B, and Hepatitis C. They are all different from each other and ...

  10. Hepatitis C: Treatment

    MedlinePlus

    ... Public Home » Hepatitis C » Hepatitis C Treatment Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For ... Enter ZIP code here Enter ZIP code here Hepatitis C Treatment for Veterans and the Public Treatment ...

  11. Transcription Factor-Mediated Regulation of Carboxylesterase Enzymes in Livers of Mice

    PubMed Central

    Zhang, Youcai; Cheng, Xingguo; Aleksunes, Lauren

    2012-01-01

    The induction of drug-metabolizing enzymes by chemicals is one of the major reasons for drug-drug interactions. In the present study, the regulation of mRNA expression of one arylacetamide deacetylase (Aadac) and 11 carboxylesterases (Cess) by 15 microsomal enzyme inducers (MEIs) was examined in livers of male C57BL/6 mice. The data demonstrated that Aadac mRNA expression was suppressed by three aryl hydrocarbon receptor (AhR) ligands, two constitutive androstane receptor (CAR) activators, two pregnane X receptor (PXR) ligands, and one nuclear factor erythroid 2-related factor 2 (Nrf2) activator. Ces1 subfamily mRNA expression was not altered by most of the MEIs, whereas Ces2 subfamily mRNA was readily induced by the activators of CAR, PXR, and Nrf2 but not by peroxisome proliferator-activated receptor α activators. Studies using null mice demonstrated that 1) AhR was required for the 2,3,7,8-tetrachlorodibenzo-p-dioxin–mediated suppression of Aadac and Ces3a; 2) CAR was involved in the 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene–mediated induction of Aadac, Ces2c, Ces2a, and Ces3a; 3) PXR was required for the pregnenolone-16α-carbonitrile–mediated induction of Aadac, Ces2c, and Ces2a; 4) Nrf2 was required for the oltipraz-mediated induction of Ces1g and Ces2c; and 5) PXR was not required for the DEX-mediated suppression of Cess in livers of mice. In conclusion, the present study systematically investigated the regulation of Cess by MEIs in livers of mice and demonstrated that MEIs modulated mRNA expression of mouse hepatic Cess through the activation of AhR, CAR, PXR, and/or Nrf2 transcriptional pathways. PMID:22429928

  12. Hepatic ischemia

    MedlinePlus

    Hepatic ischemia is a condition in which the liver does not get enough blood or oxygen, causing injury to ... pressure from any condition can lead to hepatic ischemia. Such conditions may include: Abnormal heart rhythms Dehydration ...

  13. Hepatic Encephalopathy

    MedlinePlus Videos and Cool Tools

    ... is Hepatic Encephalopathy? Hepatic Encephalopathy, sometimes referred to as portosystemic encephalopathy or PSE, is a condition that ... medical care is an important factor in staying as healthy as possible. The American Liver Foundation is ...

  14. Hepatitis D

    MedlinePlus

    ... if the hepatitis B virus is also present. Transmission Hepatitis D can be found in the blood, ... other body fluids of people who are infected. Transmission happens when infected body fluid enters another person’s ...

  15. Autoimmune hepatitis

    MedlinePlus

    Lupoid hepatitis; Chronic acute liver disease ... This form of hepatitis is an autoimmune disease . The body's immune system cannot tell the difference between healthy body tissue and harmful, outside ...

  16. Hepatitis C

    MedlinePlus

    ... 2014 Select a Language: Fact Sheet 507 Hepatitis C WHAT IS HEPATITIS C? HOW IS IT DIAGNOSED? ... treatment may be less likely to work. Hep C treatment is less effective for coinfected people. Cure ...

  17. Hepatitis A

    MedlinePlus

    ... an inflammation of the liver. One type, hepatitis A, is caused by the hepatitis A virus (HAV). The disease spreads through contact with ... washed in untreated water Putting into your mouth a finger or object that came into contact with ...

  18. Hepatitis B

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/000279.htm Hepatitis B To use the sharing features on this page, please enable JavaScript. Hepatitis B is irritation and swelling (inflammation) of the ...

  19. Modulatory effect of henna leaf (Lawsonia inermis) on drug metabolising phase I and phase II enzymes, antioxidant enzymes, lipid peroxidation and chemically induced skin and forestomach papillomagenesis in mice.

    PubMed

    Dasgupta, Trisha; Rao, A R; Yadava, P K

    2003-03-01

    Henna leaf (Lawsonia inermis), commonly known as Mehndi is cultivated throughout India and is a very popular natural dye to color hand and hair. It is an integral part of indigenous culture, and is also known for its medicinal value. The effect of 200 and 400 mg/kg body weight of 80% ethanolic extract of the fresh leaves of Lawsonia inermis were examined on drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7 weeks old Swiss albino mice. Also anticarcinogenic potential of Henna leaf extract was studied adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA)-initiated and croton oil-promoted skin papillomagenesis. Our primary findings reveal the 'duel-acting' nature of henna leaf as deduced from its potential to induce only the phase-II enzyme activity, associated mainly with carcinogen detoxification in liver of mice and inhibit the phase I enzyme activities. The hepatic glutathione S-transferase and DT-diaphorase specific activities were elevated above basal (p < 0.005) level by Lawsonia inermis extract treatment. With reference to antioxidant enzymes the investigated doses were effective in increasing the hepatic glutathione reductase (GR), superoxide dismutase (SOD) and catalase activities significantly (from p < 0.05 to p < 0.005) at both the dose levels. Reduced glutathione (GSH) measured as non-protein sulphydryl was found to be significantly elevated in liver (p < 0.005) and in all the extrahepatic organs studied (from p < 0.05 to p < 0.005). Among the extrahepatic organs examined (forestomach, kidney and lung) glutathione S-transferase and DT-diaphorase level were increased in a dose independent manner (from p < 0.05 to p < 0.005). Chemopreventive response was measured by the average number of papillomas per mouse (tumor burden) as well as percentage of tumor bearing animals and tumor multiplicity. There was a

  20. Platycodi radix saponin inhibits α-glucosidase in vitro and modulates hepatic glucose-regulating enzyme activities in C57BL/KsJ-db/db mice.

    PubMed

    Lee, Jeom-Sook; Choi, Myung-Sook; Seo, Kown-Il; Lee, Jin; Lee, Hae-In; Lee, Ju-Hye; Kim, Myung-Joo; Lee, Mi-Kyung

    2014-06-01

    This study investigated anti-diabetic activity of a concentrated saponin fraction from Platycodi radix (SK1) in C57BL/KsJ-db/db mice and its underlying mechanism. Mice were fed diet with 0.5 % SK1 (w/w) for 6 weeks. SK1 significantly lowered the blood glucose and glycosylated hemoglobin levels and improved glucose and insulin tolerance. The plasma and pancreatic insulin and C-peptide levels and fecal cholesterol content were increased, whereas plasma urea nitrogen, free fatty acid and triglyceride levels were decreased by SK1 supplementation. Glucokinase (GK) activity in the liver was significantly higher in the SK1 group than the control group, whereas the glucose-6-phosphatase (G6Pase) activity was lower. SK1 significantly down-regulated GK mRNA expression compared to the control group but did not affect G6Pase and glucose transporter 2 mRNA. Phosphoenolpyruvate carboxykinase activity and mRNA levels did not differ between groups. SK1 also markedly inhibited the small intestinal disaccharidases activities compared to those of control db/db mice. Furthermore, SK1 was a more effective α-glucosidase inhibitor than acarbose in vitro. Overall, these findings suggest that SK1 is a potential glucose-lowering agent that functions via inhibition of carbohydrate digestive enzyme activities and modulation of glucose-regulating enzyme activities in db/db mice. PMID:24105419

  1. Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity.

    PubMed

    Ogino, Yoshiyuki; Asahi, Toru

    2015-05-21

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies. PMID:25791284

  2. Hepatitis A

    MedlinePlus

    ... is an inflammation of the liver. One type, hepatitis A, is caused by the hepatitis A virus (HAV). The disease spreads through contact with ... suggest medicines to help relieve your symptoms. The hepatitis A vaccine can prevent HAV. Good hygiene can also ...

  3. Hepatitis C

    MedlinePlus

    ... an inflammation of the liver. One type, hepatitis C, is caused by the hepatitis C virus (HCV). It usually spreads through contact with ... childbirth. Most people who are infected with hepatitis C don't have any symptoms for years. If ...

  4. Hepatitis A

    MedlinePlus

    ... Organizations ​​ (PDF, 341 KB)​​​​​ Alternate Language URL Español Hepatitis A Page Content On this page: What is ... Nutrition Points to Remember Clinical Trials What is hepatitis A? Hepatitis * A is a virus , or infection, ...

  5. Autoimmune Hepatitis

    MedlinePlus

    ... Organizations ​​ (PDF, 341 KB)​​​​​ Alternate Language URL Autoimmune Hepatitis Page Content On this page: What is autoimmune ... Points to Remember Clinical Trials What is autoimmune hepatitis? Autoimmune hepatitis is a chronic—or long lasting— ...

  6. Reversible mechanisms of enzyme inhibition and resulting clinical significance.

    PubMed

    Ring, Barbara; Wrighton, Steven A; Mohutsky, Michael

    2014-01-01

    Inhibition of a drug-metabolizing enzyme by the reversible interaction of a drug with the enzyme, thus decreasing the metabolism of another drug, is a major cause of clinically significant drug-drug interactions. This chapter defines the four reversible mechanisms of inhibition exhibited by drugs: competitive, noncompetitive, uncompetitive, and mixed competitive/noncompetitive. An in vitro procedure to determine the potential of a drug to be a reversible inhibitor is also provided. Finally, a number of examples of clinically significant drug-drug interactions resulting from reversible inhibition are described. PMID:24523108

  7. Diagnostic value of anti-smooth muscle antibodies and liver enzymes in differentiation of extrahepatic biliary atresia and idiopathic neonatal hepatitis

    PubMed Central

    Rafeey, Mandana; Saboktakin, Lida; Hasani, Jamshid Shoa; Naghashi, Shahnaz

    2016-01-01

    Background: We aimed to evaluate the diagnostic value of anti-smooth muscle antibodies (ASMA) and two liver markers (gamma-glutamyl transpeptidase [GGT] and alkaline phosphatase [ALP]) for differentiating between patients with extrahepatic biliary atresia (EHBA) and idiopathic neonatal hepatitis (INH). Materials and Methods: During April 2010–2011, all infants at 2 weeks of age who were diagnosed with cholestasis and admitted to Children's Hospital of Tabriz were enrolled. Based on the results of physical examination, laboratory, imaging and pathological studies, neonates were divided into two groups (EHBA and INH). Receiver operating characteristics analysis was used to define sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for ASMA, GGT and ALP. Results: Thirty neonates with cholestasis (18 with EHBA and 12 with INH) and mean age of 54.66 ± 25.86 days were enrolled. Total and direct bilirubin, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase and ASMA titres were highly not significant (P > 0.05) in patients with INH. GGT (P = 0.008) and ALP (P = 0.01) had statistically significant differences that were higher in patients with EHBA. The sensitivity, specificity, PPV and NPV, accuracy, LR+ and LR− of SMA in differentiating cases with BA were 66.7%, 75%, 80% 60%, 70%, 2.68 and 0.44, respectively. For GGT, the values were 88.9%, 66.7%, 80%, 80%, 79.1%, 3.08 and 0.31, respectively. Finally, for ALP, the values were 77.8%, 75%, 82.4%, 69.2%, 80%, 2.66 and 0.24, respectively. Conclusion: Our study showed that ASMA may be a useful biomarker for differentiation of EHBA from INH. Further studies with larger samples are recommended for confirming the results of this study. PMID:27251654

  8. Isolation and structural characterization of 2R, 3R taxifolin 3-O-rhamnoside from ethyl acetate extract of Hydnocarpus alpina and its hypoglycemic effect by attenuating hepatic key enzymes of glucose metabolism in streptozotocin-induced diabetic rats.

    PubMed

    Balamurugan, Rangachari; Vendan, Subramanian Ezhil; Aravinthan, Adithan; Kim, Jong-Hoon

    2015-04-01

    Hydnocarpus alpina Wt. (Flacourtiaceae) (H. alpina) is a large tree traditionally used to treat leprosy; it also posses antidiabetic property. The present study was undertaken to isolate, characterize and to evaluate the antidiabetic effect of 2R, 3R taxifolin 3-O-rhamnoside. (rhamnoside) and its impact on carbohydrate metabolic key enzymes in control and streptozotocin (STZ)-induced diabetic rats. Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (STZ) (40 mg/kg). Oral administration of rhamnoside for 21 days significantly reduced food intake, calorie intake, blood glucose and glycosylated hemoglobin levels, and improved plasma insulin levels. Administration of rhamnoside showed significant increase in the body weight, body composition (Lean body weight (LBW) and retro body fat), glycolytic hexokinase, glucose-6-phophate dehydrogenase and pyruvate kinase levels where as significant decrease was observed in the levels of glucose-6-phosphatase fructose-1, 6-bisphosphatase and lactate dehydrogenase in diabetic treated rats. Further, administration of rhamnoside significantly improved the glycogen content, glycogen synthase and glycogen phosphorylase, suggesting the antihyperglycemic potential of rhamnoside in diabetic rats. The results obtained were compared with glibenclamide a standard hypoglycaemic drug. Immunohistopathological study of pancreas revealed increased number of β-cells and insulin granules in diabetes-induced rats after treatment with rhamnoside for 21 days. Furthermore, Co-administration of rhamnoside (50 mg/kg) with nifedipine (13.6 mg/kg), a Ca(2+)ion channel blocker, or nicorandil (6.8 mg/kg), an ATP-sensitive K(+) ion channel opener, reveals the insulin secretion property of rhamnoside via a K(+)-ATP channels dependent pathway in diabetic rats. In conclusion, rhamnoside normalized blood glucose, glycosylated hemoglobin, key hepatic enzymes and glycogen content by increasing insulin secretion via K

  9. Discovery of pyrazinone based compounds that potently inhibit the drug-resistant enzyme variant R155K of the hepatitis C virus NS3 protease.

    PubMed

    Belfrage, Anna Karin; Abdurakhmanov, Eldar; Kerblom, Eva; Brandt, Peter; Oshalim, Anna; Gising, Johan; Skogh, Anna; Neyts, Johan; Danielson, U Helena; Sandström, Anja

    2016-06-15

    Herein, we present the design and synthesis of 2(1H)-pyrazinone based HCV NS3 protease inhibitors with variations in the C-terminus. Biochemical evaluation was performed using genotype 1a, both the wild-type and the drug resistant enzyme variant, R155K. Surprisingly, compounds without an acidic sulfonamide retained good inhibition, challenging our previous molecular docking model. Moreover, selected compounds in this series showed nanomolar potency against R155K NS3 protease; which generally confer resistance to all HCV NS3 protease inhibitors approved or in clinical trials. These results further strengthen the potential of this novel substance class, being very different to the approved drugs and clinical candidates, in the development of inhibitors less sensitive to drug resistance. PMID:27160057

  10. Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves

    PubMed Central

    Chang, S. S.; Lohakare, J. D.; Singh, N. K.; Kwon, E. G.; Nejad, J. G.; Sung, K. I.; Hong, S. K.

    2013-01-01

    This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age) divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay) was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW) were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061) only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (p<0.01). As planned, the calves in the control group had higher concentrate and lower forage intake than the restricted group. The plasma variables like total protein and urea were higher (p<0.05) in control than restricted group. The mRNA expressions for the gluconeogenic enzymes such as cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1), and visfatin measured

  11. The impact of recent innovations in the use of liquid chromatography-mass spectrometry in support of drug metabolism studies: are we all the way there yet?

    PubMed

    Nassar, Alaa-Eldin F; Talaat, Rasmy E; Kamel, Amin M

    2006-01-01

    Absorption, distribution, metabolism, excretion and toxicology (ADMET) studies are widely used in drug discovery and development to help obtain the optimal balance of properties necessary to convert lead compounds into drugs that are safe and effective for human use. Drug discovery efforts have been aimed at identifying and addressing metabolism issues at the earliest possible stage, by developing and applying innovative liquid chromatography-mass spectrometry (LC-MS)-based techniques and instrumentation, which are both faster and more accurate than prior techniques. Such new approaches are demonstrating considerable potential to improve the overall safety profile of drug candidates throughout the drug discovery and development process. These emerging techniques streamline and accelerate the process by eliminating potentially harmful candidates earlier and improving the safety of new drugs. In the area of drug metabolism, for example, revolutionary changes have been achieved by the combination of LC-MS with innovative instrumentation such as triple quadrupoles, ion traps and time-of-flight mass spectrometry. In turn, most ADMET studies have come to rely on LC-MS for the analysis of an ever-increasing workload of potential candidates. This article provides a discussion on the importance of LC-MS in supporting drug metabolism studies, and highlights the relative merits of current applications for LC-MS in drug metabolism testing and analysis. These applications include in vitro and in vivo testing, pharmacokinetic profiling, chiral separations, stable isotope labeling, metabolic activation testing, metabolite characterization and radiolabeled-drug testing. PMID:16445118

  12. Hepatitis Vaccines

    PubMed Central

    Ogholikhan, Sina; Schwarz, Kathleen B.

    2016-01-01

    Viral hepatitis is a serious health problem all over the world. However, the reduction of the morbidity and mortality due to vaccinations against hepatitis A and hepatitis B has been a major component in the overall reduction in vaccine preventable diseases. We will discuss the epidemiology, vaccine development, and post-vaccination effects of the hepatitis A and B virus. In addition, we discuss attempts to provide hepatitis D vaccine for the 350 million individuals infected with hepatitis B globally. Given the lack of a hepatitis C vaccine, the many challenges facing the production of a hepatitis C vaccine will be shown, along with current and former vaccination trials. As there is no current FDA-approved hepatitis E vaccine, we will present vaccination data that is available in the rest of the world. Finally, we will discuss the existing challenges and questions facing future endeavors for each of the hepatitis viruses, with efforts continuing to focus on dramatically reducing the morbidity and mortality associated with these serious infections of the liver. PMID:26978406

  13. Hepatitis Vaccines.

    PubMed

    Ogholikhan, Sina; Schwarz, Kathleen B

    2016-01-01

    Viral hepatitis is a serious health problem all over the world. However, the reduction of the morbidity and mortality due to vaccinations against hepatitis A and hepatitis B has been a major component in the overall reduction in vaccine preventable diseases. We will discuss the epidemiology, vaccine development, and post-vaccination effects of the hepatitis A and B virus. In addition, we discuss attempts to provide hepatitis D vaccine for the 350 million individuals infected with hepatitis B globally. Given the lack of a hepatitis C vaccine, the many challenges facing the production of a hepatitis C vaccine will be shown, along with current and former vaccination trials. As there is no current FDA-approved hepatitis E vaccine, we will present vaccination data that is available in the rest of the world. Finally, we will discuss the existing challenges and questions facing future endeavors for each of the hepatitis viruses, with efforts continuing to focus on dramatically reducing the morbidity and mortality associated with these serious infections of the liver. PMID:26978406

  14. [Liver and drug metabolism].

    PubMed

    Mikheeva, O M

    2011-01-01

    Liver metabolism aims to change the biological activity of drugs to make them water-soluble to be excreted with bile and urine. The degree of metabolism depends on fermentative capacity for each drag (P450 fermentative system is localized in microsomal fraction of hepatocyte). Metabolism ability also changes under the influence of other substances. Liver diseases lead up to decrease of drug clirens and to increase the semi-excretion time because of reduction of liver metabolism. Therefore the drags usually undergoing intensive liver metabolism necessitate a high risk of overdose when liver diseases present. On the other hand no risk of overdose exist when drags with low liver metabolism are used. PMID:21560652

  15. Hepatitis B Vaccine

    MedlinePlus

    ... as a combination product containing Hepatitis A Vaccine, Hepatitis B Vaccine) ... What is hepatitis B?Hepatitis B is a serious infection that affects the liver. It is caused by the hepatitis B virus. ...

  16. Hepatitis A Vaccine

    MedlinePlus

    Twinrix® (as a combination product containing Hepatitis A Vaccine, Hepatitis B Vaccine) ... What is hepatitis A?Hepatitis A is a serious liver disease caused by the hepatitis A virus (HAV). HAV is found in ...

  17. Hepatitis C: Clinical Trials

    MedlinePlus

    ... and Public Home » Hepatitis C » Treatment Decisions Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For ... can I find out about participating in a hepatitis C clinical trial? Many trials are being conducted ...

  18. Autoimmune hepatitis

    MedlinePlus

    ... diseases. These include: Graves disease Inflammatory bowel disease Rheumatoid arthritis Scleroderma Sjogren syndrome Systemic lupus erythematosus Thyroiditis Type 1 diabetes Ulcerative colitis Autoimmune hepatitis may occur in family ...

  19. Hepatitis B

    MedlinePlus

    ... A Hepatitis B HPV (Human Papillomavirus) Influenza (Flu) Measles Meningococcal Disease Mumps Pertussis (Whooping Cough) Pneumococcal Disease Rubella (German Measles) Shingles (Herpes Zoster) Tetanus (Lockjaw) Professional Resources Adult ...

  20. Pharmacogenetics of ribavirin-induced anemia in hepatitis C.

    PubMed

    Ampuero, Javier; Romero-Gómez, Manuel

    2016-09-01

    Pharmacogenetics assesses inherited genetic differences in drug metabolic pathways and its role in medicine is growing. Ribavirin (RBV) and peginterferon were the standard of care therapy in hepatitis C virus infection during 15 years, with the addition of first-generation protease inhibitors at the beginning of 2010s. New direct-acting agents are the new standard of care, but RBV remains important in some scenarios. The main adverse effect of RBV is anemia, which requires dose reduction and even stopping treatment in some patients. Pharmacogenetics has identified ITPA and SLC28/29 genes to be closely related to RBV-induced anemia. The routine evaluation of these genes could help to identify those patients at risk of developing anemia during the hepatitis C virus treatment. PMID:27547881

  1. In vitro and in vivo effects of three different Mitragyna speciosa korth leaf extracts on phase II drug metabolizing enzymes--glutathione transferases (GSTs).

    PubMed

    Azizi, Juzaili; Ismail, Sabariah; Mordi, Mohd Nizam; Ramanathan, Surash; Said, Mohd Ikram Mohd; Mansor, Sharif Mahsufi

    2010-01-01

    In the present study, we investigate the effects of three different Mitragyna speciosa extracts, namely methanolic, aqueous and total alkaloid extracts, on glutathione transferase-specific activity in male Sprague Dawley rat liver cytosol in vitro and in vivo. In the in vitro study, the effect of Mitragyna speciosa extracts (0.01 to 750 microg/mL) against the specific activity of glutathione transferases was examined in rat liver cytosolic fraction from untreated rats. Our data show concentration dependent inhibition of cytosolic GSTs when Mitragyna speciosa extract was added into the reaction mixture. At the highest concentration used, the methanolic extract showed the highest GSTs specific activity inhibition (61%), followed by aqueous (50%) and total alkaloid extract (43%), respectively. In in vivo study, three different dosages; 50, 100 and 200 mg/kg for methanolic and aqueous extracts and 5, 10 and 20 mg/kg for total alkaloid extract were given orally for 14 days. An increase in GST specific activity was generally observed. However, only Mitragyna speciosa aqueous extract with a dosage of 100 mg/kg showed significant results: 129% compared to control. PMID:20110902

  2. Application of Osmotic Pumps for Sustained Release of 1-Aminobenzotriazole and Inhibition of Cytochrome P450 Enzymes in Mice: Model Comparison with the Hepatic P450 Reductase Null Mouse.

    PubMed

    Stringer, Rowan A; Ferreira, Suzie; Rose, Jonathan; Ronseaux, Sebastien

    2016-08-01

    The effectiveness of controlled release 1-aminobenzotriazole (ABT) administration to inhibit cytochrome P450 (P450) enzymes has been evaluated in mice. To maximize the duration of P450 inhibition in vivo, ABT was administered via an osmotic pump. The degree of P450 inhibition was compared with that achieved with a single bolus dose of ABT. Two-hour prior subcutaneous treatment of mice with ABT (50 mg/kg) inhibited antipyrine clearance by 88%. A less pronounced inhibitory effect (29% reduction in clearance) was observed when ABT was administered 24-hours before antipyrine administration, indicating partial restoration of P450 activity during this longer pretreatment time. The duration of ABT in mice was very short (mean residence time = 1.7 hours) after subcutaneous bolus administration. When the inhibitor was delivered by an osmotic pump, maximum blood concentrations of the inhibitor were observed 24 hours after device implantation and were maintained at steady state for 6 days. Inhibition of P450 activity, as measured by antipyrine clearance, was confirmed at 24 hours and 120 hours after pump implantation, highlighting the utility of this method as a longer-term model for P450 inhibition in mice. The magnitude of P450 inhibition in ABT-treated mice was compared with that in hepatic P450 reductase null mice and both models were comparable. In vivo ABT administration by an osmotic pump offers an effective approach for longer-term P450 inhibition in mice and avoids the necessity for multiple dosing of the inhibitor. PMID:27271368

  3. Possible drug–drug interaction in dogs and cats resulted from alteration in drug metabolism: A mini review

    PubMed Central

    Sasaki, Kazuaki; Shimoda, Minoru

    2015-01-01

    Pharmacokinetic drug–drug interactions (in particular at metabolism) may result in fatal adverse effects in some cases. This basic information, therefore, is needed for drug therapy even in veterinary medicine, as multidrug therapy is not rare in canines and felines. The aim of this review was focused on possible drug–drug interactions in dogs and cats. The interaction includes enzyme induction by phenobarbital, enzyme inhibition by ketoconazole and fluoroquinolones, and down-regulation of enzymes by dexamethasone. A final conclusion based upon the available literatures and author’s experience is given at the end of the review. PMID:26257936

  4. Enzyme markers

    MedlinePlus

    ... or defects passed down through families (inherited) can affect how enzymes work. Some enzymes are affected by several genes. Test results are usually reported as a percentage of normal enzyme activity.

  5. Modulatory Effect of Taurine on 7,12-Dimethylbenz(a)Anthracene-Induced Alterations in Detoxification Enzyme System, Membrane Bound Enzymes, Glycoprotein Profile and Proliferative Cell Nuclear Antigen in Rat Breast Tissue.

    PubMed

    Vanitha, Manickam Kalappan; Baskaran, Kuppusamy; Periyasamy, Kuppusamy; Selvaraj, Sundaramoorthy; Ilakkia, Aruldoss; Saravanan, Dhiravidamani; Venkateswari, Ramachandran; Revathi Mani, Balasundaram; Anandakumar, Pandi; Sakthisekaran, Dhanapal

    2016-08-01

    The modulatory effect of taurine on 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer in rats was studied. DMBA (25 mg/kg body weight) was administered to induce breast cancer in rats. Protein carbonyl levels, activities of membrane bound enzymes (Na(+) /K(+) ATPase, Ca(2+) ATPase, and Mg(2+) ATPase), phase I drug metabolizing enzymes (cytochrome P450, cytochrome b5, NADPH cytochrome c reductase), phase II drug metabolizing enzymes (glutathione-S-transferase and UDP-glucuronyl transferase), glycoprotein levels, and proliferative cell nuclear antigen (PCNA) were studied. DMBA-induced breast tumor bearing rats showed abnormal alterations in the levels of protein carbonyls, activities of membrane bound enzymes, drug metabolizing enzymes, glycoprotein levels, and PCNA protein expression levels. Taurine treatment (100 mg/kg body weight) appreciably counteracted all the above changes induced by DMBA. Histological examination of breast tissue further supported our biochemical findings. The results of the present study clearly demonstrated the chemotherapeutic effect of taurine in DMBA-induced breast cancer. PMID:27091720

  6. Part I---Evaluating Effects of Oligomer Formation on Cytochrome P450 2C9 Electron Transfer and Drug Metabolism, Part II---Utilizing Molecular Modeling Techniques to Study the Src-Interacting Proteins Actin Filament Associated Protein of 110 kDa (AFAP-110) and Cortactin

    NASA Astrophysics Data System (ADS)

    Jett, John Edward, Jr.

    The dissertation has been divided into two parts to accurately reflect the two distinct areas of interest pursued during my matriculation in the School of Pharmacy at West Virginia University. In Part I, I discuss research probing the nature of electron transfer in the Cytochrome P450 family of proteins, a group of proteins well-known for their role in drug metabolism. In Part II, I focus on in silico and in vitro work developed in concert to probe protein structure and protein-protein interactions involved in actin filament reorganization and cellular motility. Part I. Cytochrome P450s (P450s) are an important class of enzymes known to metabolize a variety of endogenous and xenobiotic compounds. P450s are most commonly found in liver and intestinal endothelial cells and are responsible for the metabolism of approximately 75% of pharmaceutical drugs on the market. CYP2C9---one of the six major P450 isoforms---is responsible for ˜20% of drug metabolism. Elucidation of the factors that affect in vitro drug metabolism is crucial to the accurate prediction of in vivo drug metabolism kinetics. Currently, the two major techniques for studying in vitro drug metabolism are solution-based. However, it is known that the results of solution-based studies can vary from in vivo drug metabolism. One reason suggested to account for this variation is the state of P450 oligomer formation in solution compared to the in vivo environment, where P450s are membrane-bound. To understand the details of how oligomer formation affects in vitro drug metabolism, it is imperative that techniques be developed which will allow for the unequivocal control of oligomer formation without altering other experimental parameters. Our long term goal of this research is to develop methods to more accurately predict in vivo drug metabolism from in vitro data. This section of the dissertation will discuss the development of a platform consisting of a doped silicon surface containing a large array of gold

  7. Pharmacokinetic and pharmacodynamic alterations of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors: drug-drug interactions and interindividual differences in transporter and metabolic enzyme functions.

    PubMed

    Shitara, Yoshihisa; Sugiyama, Yuichi

    2006-10-01

    3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used for the treatment of hypercholesterolemia. Their efficacy in preventing cardiovascular events has been shown by a large number of clinical trials. However, myotoxic side effects, sometimes severe, including myopathy or rhabdomyolysis, are associated with the use of statins. In some cases, such toxicity is associated with pharmacokinetic alterations. In this review, the pharmacokinetic aspects and physicochemical properties of statins are reviewed in order to understand the mechanism governing their pharmacokinetic alterations. Among the statins, simvastatin, lovastatin and atorvastatin are metabolized by cytochrome P450 3A4 (CYP3A4) while fluvastatin is metabolized by CYP2C9. Cerivastatin is subjected to 2 metabolic pathways mediated by CYP2C8 and 3A4. Pravastatin, rosuvastatin and pitavastatin undergo little metabolism. Their plasma clearances are governed by the transporters involved in the hepatic uptake and biliary excretion. Also for other statins, which are orally administered as open acid forms (i.e. fluvastatin, cerivastatin and atorvastatin), hepatic uptake transporter(s) play important roles in their clearances. Based on such information, pharmacokinetic alterations of statins can be predicted following coadministration of other drugs or in patients with lowered activities in drug metabolism and/or transport. We also present a quantitative analysis of the effect of some factors on the pharmacokinetics of statins based on a physiologically based pharmacokinetic model. To avoid a pharmacokinetic alteration, we need to have information about the metabolizing enzyme(s) and transporter(s) involved in the pharmacokinetics of statins and, along with such information, model-based prediction is also useful. PMID:16714062

  8. Eugenol-rich Fraction of Syzygium aromaticum (Clove) Reverses Biochemical and Histopathological Changes in Liver Cirrhosis and Inhibits Hepatic Cell Proliferation

    PubMed Central

    Ali, Shakir; Prasad, Ram; Mahmood, Amena; Routray, Indusmita; Shinkafi, Tijjani Salihu; Sahin, Kazim; Kucuk, Omer

    2014-01-01

    Background: Dried flower bud of Syzygium aromaticum (clove) is rich in eugenol, an antioxidant and antiinflammatory compound that can protect liver against injury. Clove, besides eugenol, also contains other pharmacologically active phytochemicals such as β-sitosterol and ascorbic acid. This study reports the effect of eugenol-rich fraction (ERF) of clove on liver cirrhosis induced by thioacetamide. Methods: Cirrhosis of the liver, which predisposes to hepatocellular carcinoma, was induced by administering thioacetamide (0.03%) in drinking water for 16 weeks. Cirrhotic animals were divided into two groups; the treated group was administered ERF for 9 weeks, one week after discontinuation of thioacetamide, while the other group received normal saline for a similar duration of time. Results: The treatment with ERF, as determined by histopathology and through a battery of biochemical markers of hepatic injury, oxidative stress and drug metabolizing enzymes, significantly ameliorated the signs of liver cirrhosis. It lowered the elevated levels of alkaline phosphatase, γ-glutamyl transferase and other biochemical changes in liver cirrhosis. Histopathology of the liver corroborated the effect of ERF with biochemical findings. ERF treatment further inhibited cell proliferation, as demonstrated by reduced [3H]-thymidine uptake. Conclusions: Data provide evidence supporting the protective action of ERF on liver cirrhosis. The study assumes significance because cirrhosis predisposes the liver to cancer, which is characterized by abnormal cell proliferation. ERF in this study is reported to inhibit hepatic cell proliferation and at the same time decrease oxidative stress, which might be the mechanism of protection against liver cirrhosis. PMID:25574464

  9. Suppression of the Nrf2-Dependent Antioxidant Response by Glucocorticoids and 11β-HSD1-Mediated Glucocorticoid Activation in Hepatic Cells

    PubMed Central

    Kratschmar, Denise V.; Calabrese, Diego; Walsh, Jo; Lister, Adam; Birk, Julia; Appenzeller-Herzog, Christian; Moulin, Pierre; Goldring, Chris E.; Odermatt, Alex

    2012-01-01

    Background Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a key transcription factor regulating a plethora of detoxifying enzymes and antioxidant genes involved in drug metabolism and defence against oxidative stress. The glucocorticoid receptor (GR) is a ligand-induced transcription factor involved in the regulation of energy supply for metabolic needs to cope with various stressors. GR activity is controlled by glucocorticoids, which are synthesized in the adrenal glands and regenerated mainly in the liver from inactive cortisone by 11β-hydroxysteroid dehydrogenase-1 (11β-HSD1). Methods and Principal Findings Using transfected HEK-293 cells and hepatic H4IIE cells we show that glucocorticoids, activated by 11β-HSD1 and acting through GR, suppress the Nrf2-dependent antioxidant response. The expression of the marker genes NQO1, HMOX1 and GST2A was suppressed upon treatment of 11β-HSD1 expressing cells with cortisone, an effect that was reversed by 11β-HSD1 inhibitors. Furthermore, our results demonstrate that elevated glucocorticoids lowered the ability of cells to detoxify H2O2. Moreover, a comparison of gene expression in male and female rats revealed an opposite sexual dimorphism with an inverse relationship between 11β-HSD1 and Nrf2 target gene expression. Conclusions The results demonstrate a suppression of the cellular antioxidant defence capacity by glucocorticoids and suggest that elevated 11β-HSD1 activity may lead to impaired Nrf2-dependent antioxidant response. The gender-specific differences in hepatic expression levels of 11β-HSD1 and Nrf2 target genes and the impact of pharmacological inhibition of 11β-HSD1 on improving cellular capacity to cope with oxidative stress warrants further studies in vivo. PMID:22606287

  10. Hepatic Encephalopathy

    PubMed Central

    Bleibel, Wissam; Al-Osaimi, Abdullah M. S.

    2012-01-01

    Chronic liver disease and cirrhosis affect hundreds of millions of patients all over the world. The majority of patients with cirrhosis will eventually develop complications related to portal hypertension. One of these recurrent and difficult to treat complications is hepatic encephalopathy. Studies have indicated that overt hepatic encephalopathy affects 30 to 45% of patients with cirrhosis and a higher percentage may be affected by minimal degree of encephalopathy. All of these factors add to the impact of hepatic encephalopathy on the healthcare system and presents a major challenge to the gastroenterologist, hospitalist and primary care physician. PMID:23006457

  11. Hepatitis B

    MedlinePlus

    ... and Change Plan Wallet card for patients to record their alcohol use over a 4-week period as a way to monitor and reduce their drinking behavior. Glossary Definitions of terms commonly used with viral hepatitis and ...

  12. Hepatitis B

    MedlinePlus

    ... U.S. Preventive Services Task Force recommendation statement. Ann Intern Med . 2014;161(1):58-66. PMID 24863637 ... Development Conference Statement: Management of hepatitis B. Ann Intern Med . 2009;150:104-10. PMID: 19124811 www. ...

  13. Role of signal-to-cut-off ratios of anti-hepatitis C virus antibody by enzyme immunoassays along with ID-NAT for screening of whole blood donors in India

    PubMed Central

    Arora, Satyam; Doda, Veena

    2016-01-01

    Background: The use of elevated signal-to-cut off ratios (S/CO) as an alternate to further supplemental testing (i.e., RIBA) has been included in the guidelines provided by the Centres for Disease Control and Prevention for HCV diagnostic purposes since 2003. With availability of screening by NAT and non availability of RIBA, further confirmation of HCV infection has been possible at the molecular level (RNA). Aims: To study the role of S/CO ratios of anti hepatitis C virus antibody detection by enzyme immunoassays (EIA) along with ID-NAT for screening of whole blood donors. Methods: In this study we reviewed the donor screening status for anti HCV from January 2013 to May 2014. All the donations were screened for anti HCV with fourth generation ELISA (BioRad Monolisa Ag-Ab Ultra) as well as with ID NAT (Procleix Ultrio). The S/CO ratio of all the anti-HCV reactive samples were analysed for their presence of HCV RNA. Results: On screening 21,115 donors for HCV, 83 donors (0.39%) were found reactive on pilot tube and repeat plasma bag testing (S/Co ratio ≥1) by ELISA. 41 donors were HCV RNA reactive with ID-NAT. 4 samples out of 41 were NAT yields and 37 were concordant reactive with ELISA. The S/Co ratio of anti-HCV reactive samples ranged from 0.9-11.1 [mean = 5.1; SD ± 2.9] whereas S/Co ratio of anti HCV and NAT reactive samples (concordant positives) ranged from 4.1-11.1 [mean 7.3]. In our analysis we found that S/CO ratio of 4 showed positive predictive value (PPV) and sensitivity of 100%. Summary/Conclusions: Our study showed that S/CO of 4 for anti HCV on ELISA would have maximum positive predictive value of having donor with HCV RNA. S/CO ratio of 4 is very close to 3.8 which was the CDC guideline. The presence of anti-HCV does not distinguish between current or past infections but a confirmed anti-HCV-positive result indicates the need for counseling and medical evaluation for HCV infection. PMID:27011676

  14. Utility of spatially-resolved atmospheric pressure surface sampling and ionization techniques as alternatives to mass spectrometric imaging (MSI) in drug metabolism

    SciTech Connect

    Blatherwick, Eleanor Q.; Van Berkel, Gary J; Pickup, Kathryn; Johansson, Maria K.; Beaudoin, Marie-Eve; Cole, Roderic; Day, Jennifer M.; Iverson, Suzanne; Wilson, Ian D.; Scrivens, James H.; Weston, Daniel J.

    2011-01-01

    1. Tissue distribution studies of drug molecules play an essential role in the pharmaceutical industry and are commonly undertaken using quantitative whole body autoradiography (QWBA) methods. 2. The growing need for complementary methods to address some scientific gaps around radiography methods has led to increased use of mass spectrometric imaging (MSI) technology over the last 5 to 10 years. More recently, the development of novel mass spectrometric techniques for ambient surface sampling has redefined what can be regarded as fit-for-purpose for MSI in a drug metabolism and disposition arena. 3. Together with a review of these novel alternatives, this paper details the use of two liquid microjunction (LMJ)- based mass spectrometric surface sampling technologies. These approaches are used to provide qualitative determination of parent drug in rat liver tissue slices using liquid extraction surface analysis (LESA) and to assess the performance of a LMJ surface sampling probe (LMJ-SSP) interface for quantitative assessment of parent drug in brain, liver and muscle tissue slices. 4. An assessment of the utility of these spatially-resolved sampling methods is given, showing interdependence between mass spectrometric and QWBA methods, in particular there emerges a reason to question typical MSI workflows for drug metabolism; suggesting the expedient use of profile or region analysis may be more appropriate, rather than generating time-intensive molecular images of the entire tissue section.

  15. Hepatitis B Foundation

    MedlinePlus

    ... worldwide 2 Billion People have been infected with Hepatitis B Worldwide The Hepatitis B Foundation is working ... of people living with hepatitis B. Learn About Hepatitis B in 10 Other Languages . Resource Video See ...

  16. Hepatitis C - children

    MedlinePlus

    ... virus (HCV). Other common hepatitis virus infections include hepatitis A and hepatitis B . ... Elisofon SA, Jonas MMF. Viral hepatitis in children. In: Boyer TD, Manns MP, Sanyal AJ, eds. Zakim & Boyer's Hepatology: A Textbook of Liver Disease. 6th ed. ...

  17. Hepatitis A FAQs

    MedlinePlus

    ... of Viral Hepatitis Contact Us Quick Links to Hepatitis ... A | B | C | D | E Viral Hepatitis Home ... Outbreaks State and Local Partners & Grantees Resource Center Hepatitis A FAQs for the Public Recommend on Facebook ...

  18. Delta agent (Hepatitis D)

    MedlinePlus

    Hepatitis D virus ... Hepatitis D virus (HDV) is found only in people who carry the hepatitis B virus. HDV may make liver ... B virus but who never had symptoms. Hepatitis D infects about 15 million people worldwide. It occurs ...

  19. Hepatitis C FAQs

    MedlinePlus

    ... of Viral Hepatitis Contact Us Quick Links to Hepatitis ... A | B | C | D | E Viral Hepatitis Home ... Outbreaks State and Local Partners & Grantees Resource Center Hepatitis C FAQs for the Public Recommend on Facebook ...

  20. Hepatitis B FAQs

    MedlinePlus

    ... of Viral Hepatitis Contact Us Quick Links to Hepatitis ... A | B | C | D | E Viral Hepatitis Home ... Outbreaks State and Local Partners & Grantees Resource Center Hepatitis B FAQs for the Public Recommend on Facebook ...

  1. Hepatitis A Test

    MedlinePlus

    ... be limited. Home Visit Global Sites Search Help? Hepatitis A Testing Share this page: Was this page ... HAV-Ab total; Anti-HAV Formal name: Viral Hepatitis A Antibody Related tests: Hepatitis B Testing ; Hepatitis ...

  2. Feature Hepatitis: Hepatitis Symptoms, Diagnosis, Treatment & Prevention

    MedlinePlus

    ... Current Issue Past Issues Feature Hepatitis Hepatitis: Symptoms, Diagnosis, Treatment & Prevention Past Issues / Spring 2009 Table of ... Stomach ache Nausea Diarrhea No appetite Fever Headaches Diagnosis To check for hepatitis viruses, your doctor will ...

  3. Radiation Exposure Alters Expression of Metabolic Enzyme Genes In Mice

    NASA Technical Reports Server (NTRS)

    Wotring, Virginia E.; Mangala, L. S.; Zhang, Y.; Wu, H.

    2010-01-01

    Most pharmaceuticals are metabolized by the liver. The health of the liver, especially the rate of its metabolic enzymes, determines the concentration of circulating drugs as well as the duration of their efficacy. Because of the importance of the liver in drug metabolism it is important to understand the effects of spaceflight on the enzymes of the liver. Exposure to cosmic radiation is one aspect of spaceflight that can be modeled in ground experiments. This study is an effort to examine the effects of adaptive mechanisms that may be triggered by early exposure to low radiation doses. Using procedures approved by the JSC Animal Care & Use Committee, C57 male mice were exposed to Cs-137 in groups: controls, low dose (50 mGy), high dose (6Gy) and a fourth group that received both radiation doses separated by 24 hours. Animals were anesthetized and sacrificed 4 hours after their last radiation exposure. Livers were removed immediately and flash-frozen in liquid nitrogen. Tissue was homogenized, RNA extracted and purified (Absolutely RNA, Agilent). Quality of RNA samples was evaluated (Agilent Bioanalyzer 2100). Complementary DNA was prepared from high-quality RNA samples, and used to run RT-qPCR screening arrays for DNA Repair and Drug Metabolism (SuperArray, SABiosciences/Qiagen; BioRad Cfx96 qPCR System). Of 91 drug metabolism genes examined, expression of 7 was altered by at least one treatment condition. Genes that had elevated expression include those that metabolize promethazine and steroids (4-8-fold), many that reduce oxidation products, and one that reduces heavy metal exposure (greater than 200-fold). Of the 91 DNA repair and general metabolism genes examined, expression of 14 was altered by at least one treatment condition. These gene expression changes are likely homeostatic and could lead to development of new radioprotective countermeasures.

  4. The wild Egyptian artichoke as a promising functional food for the treatment of hepatitis C virus as revealed via UPLC-MS and clinical trials.

    PubMed

    Elsebai, Mahmoud Fahmi; Abass, Khaled; Hakkola, Jukka; Atawia, Ahmed Rezk; Farag, Mohamed A

    2016-07-13

    Infection by hepatitis C virus (HCV) and its subsequent complications are a major cause of mortality worldwide. The water extract of the wild Egyptian artichoke (WEA) (Cynara cardunculus L. var. sylvestris (Lam.) Fiori) leaves is a freely available herbal product that is used for treatment of HCV-infection complications such as jaundice and ascites. The purpose of this study was to evaluate whether WEA exhibits activity against HCV, identify bioactive chemicals in its extract and to tentatively examine the potential inhibitory interactions of WEA with human drug-metabolizing enzymes. The current pilot clinical trial revealed that the water extract of a WEA plant decreased the HCV viral load below the detection level in 12 out of 15 patients. Furthermore, the liver enzymes ALT and AST, as well as the level of bilirubin were normalized. The total WEA extract inhibited CYP2B6 (OH-BUP) and CYP2C19 (5-OH-OME) with high affinity, IC50 ∼ 20 μg ml(-1), while moderate inhibitory interactions were observed for CYP1A2, CYP2D6, CYP2E1 and CYP3A4. Results presented herein suggest that the WEA exhibits strong antiviral activity against HCV and may be useful for its treatment. Compared to the artichoke product "Hepar SL Forte(®)", WEA was found to be more enriched in sesquiterpenes versus the abundance of phenolic compounds, especially flavonoids in Hepar SL Forte(®) as revealed via UPLC-MS analysis coupled to chemometrics. PMID:27296047

  5. Hepatitis C: Sex and Sexuality

    MedlinePlus

    ... with Hepatitis » Sex and Sexuality: Entire Lesson Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For ... hepatitis C virus through sex. Can you pass hepatitis C to a sex partner? Yes, but it ...

  6. Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Moe, Owen; Cornelius, Richard

    1988-01-01

    Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

  7. Hepatitis C

    PubMed Central

    Mehta, Bharti; Kumar Dharma, Vijay; Chawla, Sumit; Jindal, Harashish; Bhatt, Bhumika

    2014-01-01

    Hepatitis C Virus (HCV) infection is a major cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Following acute infection, 20% of people eliminate the virus over weeks or months and are often asymptomatic. The remaining 80% of people will develop chronic disease, of which approximately 20% will eventually develop liver cirrhosis and 1–5% will develop liver cancer. About 150 million people are chronically infected with HCV, and more than 350 000 people die every year from hepatitis C related liver diseases. The economic cost of hepatitis C is significant both to the individual and to the society. In the United States the average lifetime cost of the disease was estimated at $33 407 USD with the cost of a liver transplant approximately $200 000 USD. PEG-IFN and ribavirin treatment is also expensive and, at an average cost of approximately GB £7000 in the UK for a treatment course, is unaffordable in developing countries. Hepatitis C, not only brings down the quality of the life of individuals but also affect progress of the nation by adding financial burden. If we prevent the disease from occurring or find a perfect cure of the disease, in form of a prophylactic or therapeutic vaccine, it will be a boon to not only to the individual but to the nation as a whole. PMID:24165512

  8. Hepatic encephalopathy.

    PubMed

    Córdoba, Juan; Mínguez, Beatriz

    2008-02-01

    Hepatic encephalopathy is a severe complication of cirrhosis that is related to the effects of ammonia. Analysis of interorgan ammonia trafficking has identified an important role of skeletal muscle in ammonia removal and has highlighted the importance of the nutritional status. Ammonia causes neurotransmitter abnormalities and induces injury to astrocytes that is partially mediated by oxidative stress. These disturbances lead to astrocyte swelling and brain edema, which appear to be involved in the pathogenesis of neurological manifestations. Inflammatory mediators worsen brain disturbances. New methods for assessing hepatic encephalopathy include clinical scales, neuropsychological tests, imaging of portal-systemic circulation, and magnetic resonance of the brain. Reappraisal of current therapy indicates the need for performing placebo-controlled trials and the lack of evidence for administering diets with restricted protein content. Liver transplant should be considered in selected patients with hepatic encephalopathy. Future prospects include new drugs that decrease plasma ammonia, measures to reduce brain edema, and liver-support devices. PMID:18293278

  9. [Hepatic encephalopathy].

    PubMed

    Córdoba, Juan; Mur, Rafael Esteban

    2014-07-01

    Hepatic encephalopathy (EH) is a severe complication of hepatic cirrhosis that is characterized by multiple neuropsychiatric manifestations. EH is usually triggered by a precipitating factor and occurs in patients with severely impaired hepatic function. Minimal EH is characterized by minor cognitive impairments that are difficult to specify but represent a risk for the patients. The primary pathophysiological mechanism of EH is considered to be an increase in blood ammonia with an impairment in the patency of the blood-brainbarrier and its metabolism to glutamine in astrocytes. The diagnosis is clinical and neuroimaging techniques can be complementary. The diagnosis of minimal EH requires specific neurocognitive tests. The clinical evaluation should be directed towards identifying the trigger. Nonabsorbable disaccharides and rifaximin constitute the treatment of choice, along with prophylaxis for new episodes. PMID:25087716

  10. Evaluation of possible inhibition of human liver drug metabolizing cytochromes P450 by two new acetylcholinesterase oxime-type reactivators.

    PubMed

    Spicakova, Alena; Anzenbacher, Pavel; Liskova, Barbora; Kuca, Kamil; Fusek, Josef; Anzenbacherova, Eva

    2016-02-01

    Two non-symmetric bispyridine oxime - based reactivators of acetylcholinesterase enzyme (AChE), labeled as K027 (1-(4-carbamoylpyridinium)-3-(4-hydroxyiminomethylpyridinium)-propane dibromide) and K203 ((E)-1-(4- carbamoylpyridinium)-4-(4-hydroxyiminomethylpyridinium)-but-2-ene dibromide) were tested for their potential to inhibit activities of human liver microsomal cytochromes P450 (CYP). Both oximes are very potent reactivators of organophosphate-inhibited AChE. An interaction of both compounds with CYP in human liver microsomal preparation was detected using difference spectroscopy. The compounds were shown to bind to CYP enzymes with spectral binding constants of 5.04 ± 1.79 nM (K027) and 5.2 ± 2.6 nM (K203). Enzymology studies were subsequently performed aimed at determining which of the nine most important CYP involved in drug is affected by this interaction. The results have shown no prominent inhibition of individual CYP activities with either compounds except in the case of CYP2E1 and K203. Diagnostic Dixon plot revealed that K203 acted as an uncompetitive inhibitor of CYP2E1. Inhibition of this activity however is not as prominent as to make a potent drug interaction likely. Hence, the interaction of K027 and K203 oxime-type AChE reactivators with human liver microsomal CYP enzymes does not seem to be of prominent clinical importance and both compounds could be safely used in this respect as antidotes with low risk of drug interactions. PMID:26747974

  11. Radiation Exposure Alters Expression of Metabolic Enzyme Genes in Mice

    NASA Technical Reports Server (NTRS)

    Wotring, V. E.; Mangala, L. S.; Zhang, Y.; Wu, H.

    2011-01-01

    Most administered pharmaceuticals are metabolized by the liver. The health of the liver, especially the rate of its metabolic enzymes, determines the concentration of circulating drugs as well as the duration of their efficacy. Most pharmaceuticals are metabolized by the liver, and clinically-used medication doses are given with normal liver function in mind. A drug overdose can result in the case of a liver that is damaged and removing pharmaceuticals from the circulation at a rate slower than normal. Alternatively, if liver function is elevated and removing drugs from the system more quickly than usual, it would be as if too little drug had been given for effective treatment. Because of the importance of the liver in drug metabolism, we want to understand the effects of spaceflight on the enzymes of the liver and exposure to cosmic radiation is one aspect of spaceflight that can be modeled in ground experiments. Additionally, it has been previous noted that pre-exposure to small radiation doses seems to confer protection against later and larger radiation doses. This protective power of pre-exposure has been called a priming effect or radioadaptation. This study is an effort to examine the drug metabolizing effects of radioadaptation mechanisms that may be triggered by early exposure to low radiation doses.

  12. The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication

    PubMed Central

    Ouzzine, Mohamed; Gulberti, Sandrine; Ramalanjaona, Nick; Magdalou, Jacques; Fournel-Gigleux, Sylvie

    2014-01-01

    UDP-glucuronosyltransferases (UGTs) form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the formation of β-D-glucuronides from structurally unrelated substances (drugs, other xenobiotics, as well as endogenous compounds) by the linkage of glucuronic acid from the high energy donor, UDP-α-D-glucuronic acid. In brain, UGTs actively participate to the overall protection of the tissue against the intrusion of potentially harmful lipophilic substances that are metabolized as hydrophilic glucuronides. These metabolites are generally inactive, except for important pharmacologically glucuronides such as morphine-6-glucuronide. UGTs are mainly expressed in endothelial cells and astrocytes of the blood brain barrier (BBB). They are also associated to brain interfaces devoid of BBB, such as circumventricular organ, pineal gland, pituitary gland and neuro-olfactory tissues. Beside their key-role as a detoxication barrier, UGTs play a role in the steady-state of endogenous compounds, like steroids or dopamine (DA) that participate to the function of the brain. UGT isoforms of family 1A, 2A, 2B and 3A are expressed in brain tissues to various levels and are known to present distinct but overlapping substrate specificity. The importance of these enzyme species with regard to the formation of toxic, pharmacologically or physiologically relevant glucuronides in the brain will be discussed. PMID:25389387

  13. Evidence of drug metabolism by macrophages: possible role of macrophages in the pathogenesis of drug-induced tissue damage and in the activation of environmental procarcinogens.

    PubMed

    Wickramasinghe, S N

    1987-01-01

    After interaction with human macrophages derived from blood, bone marrow or spleen, solutions of sodium phenobarbitone, phenytoin sodium and chlorpromazine hydrochloride showed reduced cytotoxicity towards K562 cells. The reduction in cytotoxicity was partially suppressed in the presence of tetrahydrofurane, an inhibitor of cytochrome P450. These data suggest that macrophages are capable of metabolizing certain drugs, probably via a cytochrome P450-dependent mechanism. The present findings raise the possibility that some drug-induced blood dyscrasias are caused by metabolism of the drug by bone marrow macrophages and the consequent release of relatively short-lived molecules which are toxic to adjacent haemopoietic cells. The generation of cytotoxic molecules during drug metabolism by macrophages may also be responsible for drug-induced damage to other macrophage-rich tissues. In addition, since cytochrome P450-dependent reactions seem to occur within macrophages, these cells may activate environmental procarcinogens and thus plays a role in carcinogenesis and leukaemogenesis. PMID:3652639

  14. Enzyme Informatics

    PubMed Central

    Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

    2012-01-01

    Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

  15. Conference Report: Drug Metabolism Discussion Group Short Meeting: microsampling--the next big thing. Alderley Park, Macclesfield, UK, 14 March 2012.

    PubMed

    Jackson-Addie, Kirsty; Woods, Karen; Muir, Allan; Smith, Christopher; Higton, David

    2012-12-01

    On behalf of the Drug Metabolism Discussion Group, Regulatory Bioanalysis AstraZeneca (UK) recently organized and hosted an extremely successful Drug Metabolism Discussion Group Short Meeting on 'microsampling--the next big thing'. This attracted over 140 delegates and a strong line up of presenters of respected scientists within the field. This meeting focused on the impact of taking a reduced sample (5-20 µl) from an animal, or later in the clinic, particularly neonates. The agenda covered the spectrum of microsampling, from capillary plasma microsampling, as championed by Ove Jonsson and Kristian Königsson, through to dried blood spots. The day was split up in to three sections, the morning concentrating on the sampling aspects from animals. A highlight of the first section was the 'poster blitz' where four poster presenters gave a quick overview of their work. This introduced the poster session and created a good atmosphere for general debate between the delegates. The mid-session saw the bioanalytical challenges discussed from the discovery to the preclinical stage. To encourage interaction between the presenters and the audience, a panel discussion was used that led to interesting insights into study design from toxicological and bioanalytical viewpoints. The final session was left to clinical aspects of microsampling and a particularly interesting presentation from Hitesh Pandya from the Pediatric Respiratory Medicine Department (University of Leicester, Leicester, UK). An eloquent and hard-hitting presentation put into perspective the importance of advancements in this field that enables sample to be taken in a noninvasive manner. The meeting was well received with excellent feedback from all concerned. PMID:23216118

  16. Hepatitis A

    MedlinePlus

    ... Low-grade fever Nausea and vomiting Pale or clay-colored stools Yellow skin (jaundice) ... The virus does not remain in the body after the infection is gone. Most people with hepatitis A recover within 3 months. Nearly all people get better within 6 months. There ...

  17. Autoimmune Hepatitis

    MedlinePlus

    ... provider will closely monitor and manage any side effects that may occur, as high doses of prednisone are often prescribed to treat autoimmune hepatitis. Immune system suppressors. Medications that suppress the immune system prevent the body from making autoantibodies and block the immune reaction ...

  18. Hepatitis A

    MedlinePlus

    ... Advisory Board Sponsors Sponsorship Opporunities Spread the Word Shop AAP Find a Pediatrician ... Body Hepatitis means “inflammation of the liver.” This inflammation can be caused by a wide variety of toxins, drugs, and metabolic diseases, as well as infection. There ...

  19. INDUCIBILITY OF HEPATIC CYP1A ENZYMES BY 3-METHYLCHOLANTHRENE AND ISOSAFROLE DIFFERS IN MALE RATS FED DIETS CONTAINING CASEIN, SOY PROTEIN ISOLATE OR WHEY FROM CONCEPTION TO ADULTHOOD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One possible mechanism by which diet may reduce cancer risk is through enhancement of metabolic systems that prevent activation of carcinogens or accelerate carcinogen inactivation. We studied the effects of diet and 7,12-dimethylbenz-(a)anthracene (DMBA) on hepatic and mammary gland CYP1A1, CYP1A2...

  20. Enzymes, Industrial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymes serve key roles in numerous biotechnology processes and products that are commonly encountered in the forms of food and beverages, cleaning supplies, clothing, paper products, transportation fuels, pharmaceuticals, and monitoring devices. Enzymes can display regio- and stereo-specificity, p...

  1. Understanding Enzymes.

    ERIC Educational Resources Information Center

    Sinnott, M. L.

    1979-01-01

    Describes the way enzymes operate through reaction energetics, and explains that most of the catalytic power of enzymes lies in the strong noncovalent forces responsible for initial binding of substrate, which are only manifested at the transition state of the reaction. (Author/GA)

  2. Soil Enzymes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The functionality and resilience of natural and managed ecosystems mainly rely on the metabolic abilities of microbial communities, the main source of enzymes in soils. Enzyme mediated reactions are critical in the decomposition of organic matter, cycling of nutrients, and in the breakdown of herbic...

  3. Detoxifying Enzymes at the Cross-Roads of Inflammation, Oxidative Stress, and Drug Hypersensitivity: Role of Glutathione Transferase P1-1 and Aldose Reductase

    PubMed Central

    Sánchez-Gómez, Francisco J.; Díez-Dacal, Beatriz; García-Martín, Elena; Agúndez, José A. G.; Pajares, María A.; Pérez-Sala, Dolores

    2016-01-01

    Phase I and II enzymes are involved in the metabolism of endogenous reactive compounds as well as xenobiotics, including toxicants and drugs. Genotyping studies have established several drug metabolizing enzymes as markers for risk of drug hypersensitivity. However, other candidates are emerging that are involved in drug metabolism but also in the generation of danger or costimulatory signals. Enzymes such as aldo-keto reductases (AKR) and glutathione transferases (GST) metabolize prostaglandins and reactive aldehydes with proinflammatory activity, as well as drugs and/or their reactive metabolites. In addition, their metabolic activity can have important consequences for the cellular redox status, and impacts the inflammatory response as well as the balance of inflammatory mediators, which can modulate epigenetic factors and cooperate or interfere with drug-adduct formation. These enzymes are, in turn, targets for covalent modification and regulation by oxidative stress, inflammatory mediators, and drugs. Therefore, they constitute a platform for a complex set of interactions involving drug metabolism, protein haptenation, modulation of the inflammatory response, and/or generation of danger signals with implications in drug hypersensitivity reactions. Moreover, increasing evidence supports their involvement in allergic processes. Here, we will focus on GSTP1-1 and aldose reductase (AKR1B1) and provide a perspective for their involvement in drug hypersensitivity. PMID:27540362

  4. Detoxifying Enzymes at the Cross-Roads of Inflammation, Oxidative Stress, and Drug Hypersensitivity: Role of Glutathione Transferase P1-1 and Aldose Reductase.

    PubMed

    Sánchez-Gómez, Francisco J; Díez-Dacal, Beatriz; García-Martín, Elena; Agúndez, José A G; Pajares, María A; Pérez-Sala, Dolores

    2016-01-01

    Phase I and II enzymes are involved in the metabolism of endogenous reactive compounds as well as xenobiotics, including toxicants and drugs. Genotyping studies have established several drug metabolizing enzymes as markers for risk of drug hypersensitivity. However, other candidates are emerging that are involved in drug metabolism but also in the generation of danger or costimulatory signals. Enzymes such as aldo-keto reductases (AKR) and glutathione transferases (GST) metabolize prostaglandins and reactive aldehydes with proinflammatory activity, as well as drugs and/or their reactive metabolites. In addition, their metabolic activity can have important consequences for the cellular redox status, and impacts the inflammatory response as well as the balance of inflammatory mediators, which can modulate epigenetic factors and cooperate or interfere with drug-adduct formation. These enzymes are, in turn, targets for covalent modification and regulation by oxidative stress, inflammatory mediators, and drugs. Therefore, they constitute a platform for a complex set of interactions involving drug metabolism, protein haptenation, modulation of the inflammatory response, and/or generation of danger signals with implications in drug hypersensitivity reactions. Moreover, increasing evidence supports their involvement in allergic processes. Here, we will focus on GSTP1-1 and aldose reductase (AKR1B1) and provide a perspective for their involvement in drug hypersensitivity. PMID:27540362

  5. Unravelling the transcriptomic landscape of the major phase II UDP-glucuronosyltransferase drug metabolizing pathway using targeted RNA sequencing.

    PubMed

    Tourancheau, A; Margaillan, G; Rouleau, M; Gilbert, I; Villeneuve, L; Lévesque, E; Droit, A; Guillemette, C

    2016-02-01

    A comprehensive view of the human UDP-glucuronosyltransferase (UGT) transcriptome is a prerequisite to the establishment of an individual's UGT metabolic glucuronidation signature. Here, we uncover the transcriptome landscape of the 10 human UGT gene loci in normal and tumoral metabolic tissues by targeted RNA next-generation sequencing. Alignment on the human hg19 reference genome identifies 234 novel exon-exon junctions. We recover all previously known UGT1 and UGT2 enzyme-coding transcripts and identify over 130 structurally and functionally diverse novel UGT variants. We further expose a revised genomic structure of UGT loci and provide a comprehensive repertoire of transcripts for each UGT gene. Data also uncover a remodelling of the UGT transcriptome occurring in a tissue- and tumor-specific manner. The complex alternative splicing program regulating UGT expression and protein functions is likely critical in determining detoxification capacity of an organ and stress-related responses, with significant impact on drug responses and diseases. PMID:25869014

  6. Variation in Human Cytochrome P-450 Drug-Metabolism Genes: A Gateway to the Understanding of Plasmodium vivax Relapses

    PubMed Central

    Silvino, Ana Carolina Rios; Costa, Gabriel Luiz; de Araújo, Flávia Carolina Faustino; Ascher, David Benjamin; Pires, Douglas Eduardo Valente; Fontes, Cor Jesus Fernandes; Carvalho, Luzia Helena; de Brito, Cristiana Ferreira Alves; Sousa, Tais Nobrega

    2016-01-01

    Although Plasmodium vivax relapses are classically associated with hypnozoite activation, it has been proposed that a proportion of these cases are due to primaquine (PQ) treatment failure caused by polymorphisms in cytochrome P-450 2D6 (CYP2D6). Here, we present evidence that CYP2D6 polymorphisms are implicated in PQ failure, which was reinforced by findings in genetically similar parasites, and may explain a number of vivax relapses. Using a computational approach, these polymorphisms were predicted to affect the activity of CYP2D6 through changes in the structural stability that could lead to disruption of the PQ-enzyme interactions. Furthermore, because PQ is co-administered with chloroquine (CQ), we investigated whether CQ-impaired metabolism by cytochrome P-450 2C8 (CYP2C8) could also contribute to vivax recurrences. Our results show that CYP2C8-mutated patients frequently relapsed early (<42 days) and had a higher proportion of genetically similar parasites, suggesting the possibility of recrudescence due to CQ therapeutic failure. These results highlight the importance of pharmacogenetic studies as a tool to monitor the efficacy of antimalarial therapy. PMID:27467145

  7. Prediction of interindividual differences in hepatic functions and drug sensitivity by using human iPS-derived hepatocytes

    PubMed Central

    Takayama, Kazuo; Morisaki, Yuta; Kuno, Shuichi; Nagamoto, Yasuhito; Harada, Kazuo; Furukawa, Norihisa; Ohtaka, Manami; Nishimura, Ken; Imagawa, Kazuo; Sakurai, Fuminori; Tachibana, Masashi; Sumazaki, Ryo; Noguchi, Emiko; Nakanishi, Mahito; Hirata, Kazumasa; Kawabata, Kenji; Mizuguchi, Hiroyuki

    2014-01-01

    Interindividual differences in hepatic metabolism, which are mainly due to genetic polymorphism in its gene, have a large influence on individual drug efficacy and adverse reaction. Hepatocyte-like cells (HLCs) differentiated from human induced pluripotent stem (iPS) cells have the potential to predict interindividual differences in drug metabolism capacity and drug response. However, it remains uncertain whether human iPSC-derived HLCs can reproduce the interindividual difference in hepatic metabolism and drug response. We found that cytochrome P450 (CYP) metabolism capacity and drug responsiveness of the primary human hepatocytes (PHH)-iPS-HLCs were highly correlated with those of PHHs, suggesting that the PHH-iPS-HLCs retained donor-specific CYP metabolism capacity and drug responsiveness. We also demonstrated that the interindividual differences, which are due to the diversity of individual SNPs in the CYP gene, could also be reproduced in PHH-iPS-HLCs. We succeeded in establishing, to our knowledge, the first PHH-iPS-HLC panel that reflects the interindividual differences of hepatic drug-metabolizing capacity and drug responsiveness. PMID:25385620

  8. [Hepatic encephalopathy].

    PubMed

    Jacques, Jérémie; Carrier, Paul; Debette-Gratien, Marilyne; Sobesky, Rodolphe; Loustaud-Ratti, Véronique

    2016-01-01

    Hepatic encephalopathy is a severe complication of liver cirrhosis and is an important therapeutic challenge, with a social and economic issue. If, now, the pathophysiology is not totally understood (main role of ammonia, but a better understanding of cerebral mechanisms), the clinical presentation is well-known. Some treatments are useful (disaccharides, treatment of the trigger) but their efficiency is limited. Nevertheless, the emergence of new treatments, such as non-absorbable antibiotics (rifaximin essentially), is an interesting therapeutic tool. PMID:26597584

  9. Drug-induced hepatitis

    MedlinePlus

    Toxic hepatitis ... to get liver damage. Some drugs can cause hepatitis with small doses, even if the liver breakdown ... liver. Many different drugs can cause drug-induced hepatitis. Painkillers and fever reducers that contain acetaminophen are ...

  10. Hepatitis A - children

    MedlinePlus

    ... have the virus and do not practice good hygiene. Other common hepatitis virus infections include hepatitis B ... where diapers are changed to ensure that proper hygiene is followed. If your child gets hepatitis A, ...

  11. Hepatitis B virus (image)

    MedlinePlus

    Hepatitis B is also known as serum hepatitis and is spread through blood and sexual contact. It is ... population. This photograph is an electronmicroscopic image of hepatitis B virus particles. (Image courtesy of the Centers for ...

  12. Preventing hepatitis A

    MedlinePlus

    Hepatitis A is inflammation (irritation and swelling) of the liver caused by the hepatitis A virus. You can take several steps to ... reduce your risk of spreading or catching the hepatitis A virus: Always wash your hands thoroughly after ...

  13. What Is Hepatitis?

    MedlinePlus

    ... Twitter Facebook Google + iTunes Play Store What is hepatitis? Online Q&A Reviewed July 2016 Q: What ... Question and answer archives Submit a question World Hepatitis Day Know hepatitis - Act now Event notice Key ...

  14. Drug-Metabolizing Activity, Protein and Gene Expression of UDP-Glucuronosyltransferases Are Significantly Altered in Hepatocellular Carcinoma Patients

    PubMed Central

    Lu, Linlin; Zhou, Juan; Shi, Jian; Peng, Xiao-juan; Qi, Xiao-xiao; Wang, Ying; Li, Fang-yuan; Zhou, Fu-Yuan; Liu, Liang; Liu, Zhong-Qiu

    2015-01-01

    UDP-glucuronosyltransferases (UGTs), the most important enzymes in body detoxification and homeostasis maintaining, govern the glucuronidation reaction of various endogenous and environmental carcinogens. The metabolic function of UGTs can be severely influenced by hepatocellular carcinoma (HCC), the fifth prevalent and third malignant cancer worldwide. Particularly in China, HBV-positive HCC account for approximately 80% of HCC patients. But rare papers addressed the alteration on the metabolism of UGTs specific substrates, translational and transcriptional activity of UGTs in HBV-positive HCC patients. In present study, we choose the main UGT isoforms, UGT1As, UGT1A1, UGT1A9, UGT1A4 and UGT2B7, to determine the alterations of metabolic activity, protein and gene expression of UGTs in HBV-positive HCC. The corresponding specific substrates such as genistein, SN-38, tamoxifen, propofol and zidovudine were utilized respectively in UGTs metabolic activity determination. Furthermore, the plausible mechanism responsible for UGTs alterations was addressed by analyzing the protein and gene expressions in tumor and the adjacent normal tissues in HBV-positive HCC. The results revealed that in the tumor human liver microsomes (HLMs), either Vmax (maximum reaction rate, Rmax for UGT1A1) or the clearance rates (Vmax/Km, Clint) of UGT1A, UGT1A1, UGT1A4, UGT1A9 and UGT2B7 were significant lower than those of in the adjacent normal HLMs. Subsequently, the relative protein and gene expressions of these isoforms were notably decreased in most of tumor tissues comparing with the adjacent normal tissues. More interestingly, in tumor tissues, the metabolic activity reduction ratio of each UGT isoform was closely related to its protein reduction ratio, indicating that decreasing protein level would contribute to the reduced metabolic function of UGTs in HBV-positive HCC. In summary, our study firstly determined the alteration of UGT function in HBV-positive HCC patients, which would

  15. Drug-Metabolizing Activity, Protein and Gene Expression of UDP-Glucuronosyltransferases Are Significantly Altered in Hepatocellular Carcinoma Patients.

    PubMed

    Lu, Linlin; Zhou, Juan; Shi, Jian; Peng, Xiao-juan; Qi, Xiao-xiao; Wang, Ying; Li, Fang-Yuan; Zhou, Fu-Yuan; Liu, Liang; Liu, Zhong-Qiu

    2015-01-01

    UDP-glucuronosyltransferases (UGTs), the most important enzymes in body detoxification and homeostasis maintaining, govern the glucuronidation reaction of various endogenous and environmental carcinogens. The metabolic function of UGTs can be severely influenced by hepatocellular carcinoma (HCC), the fifth prevalent and third malignant cancer worldwide. Particularly in China, HBV-positive HCC account for approximately 80% of HCC patients. But rare papers addressed the alteration on the metabolism of UGTs specific substrates, translational and transcriptional activity of UGTs in HBV-positive HCC patients. In present study, we choose the main UGT isoforms, UGT1As, UGT1A1, UGT1A9, UGT1A4 and UGT2B7, to determine the alterations of metabolic activity, protein and gene expression of UGTs in HBV-positive HCC. The corresponding specific substrates such as genistein, SN-38, tamoxifen, propofol and zidovudine were utilized respectively in UGTs metabolic activity determination. Furthermore, the plausible mechanism responsible for UGTs alterations was addressed by analyzing the protein and gene expressions in tumor and the adjacent normal tissues in HBV-positive HCC. The results revealed that in the tumor human liver microsomes (HLMs), either V(max) (maximum reaction rate, R(max) for UGT1A1) or the clearance rates (V(max)/K(m), Clint) of UGT1A, UGT1A1, UGT1A4, UGT1A9 and UGT2B7 were significant lower than those of in the adjacent normal HLMs. Subsequently, the relative protein and gene expressions of these isoforms were notably decreased in most of tumor tissues comparing with the adjacent normal tissues. More interestingly, in tumor tissues, the metabolic activity reduction ratio of each UGT isoform was closely related to its protein reduction ratio, indicating that decreasing protein level would contribute to the reduced metabolic function of UGTs in HBV-positive HCC. In summary, our study firstly determined the alteration of UGT function in HBV-positive HCC patients, which

  16. Effects of ciprofibrate and 2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA) on the distribution of carnitine and CoA and their acyl-esters and on enzyme activities in rats. Relation between hepatic carnitine concentration and carnitine acetyltransferase activity.

    PubMed Central

    Bhuiyan, A K; Bartlett, K; Sherratt, H S; Agius, L

    1988-01-01

    The effects of feeding the peroxisome proliferators ciprofibrate (a hypolipidaemic analogue of clofibrate) or POCA (2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate) (an inhibitor of CPT I) to rats for 5 days on the distribution of carnitine and acylcarnitine esters between liver, plasma and muscle and on hepatic CoA concentrations (free and acylated) and activities of carnitine acetyltransferase and acyl-CoA hydrolases were determined. Ciprofibrate and POCA increased hepatic [total CoA] by 2 and 2.5 times respectively, and [total carnitine] by 4.4 and 1.9 times respectively, but decreased plasma [carnitine] by 36-46%. POCA had no effect on either urinary excretion of acylcarnitine esters or [acylcarnitine] in skeletal muscle. By contrast, ciprofibrate decreased [acylcarnitine] and [total carnitine] in muscle. In liver, ciprofibrate increased the [carnitine]/[CoA] ratio and caused a larger increase in [acylcarnitine] (7-fold) than in [carnitine] (4-fold), thereby increasing the [short-chain acylcarnitine]/[carnitine] ratio. POCA did not affect the [carnitine]/[CoA] and the [short-chain acylcarnitine]/[carnitine] ratios, but it decreased the [long-chain acylcarnitine]/[carnitine] ratio. Ciprofibrate and POCA increased the activities of acyl-CoA hydrolases, and carnitine acetyltransferase activity was increased 28-fold and 6-fold by ciprofibrate and POCA respectively. In cultures of hepatocytes, ciprofibrate caused similar changes in enzyme activity to those observed in vivo, although [carnitine] decreased with time. The results suggest that: (1) the reactions catalysed by the short-chain carnitine acyltransferases, but not by the carnitine palmitoyltransferases, are near equilibrium in liver both before and after modification of metabolism by administration of ciprofibrate or POCA; (2) the increase in hepatic [carnitine] after ciprofibrate or POCA feeding can be explained by redistribution of carnitine between tissues; (3) the activity of carnitine

  17. Feature Hepatitis: Hepatitis Symptoms, Diagnosis, Treatment & Prevention

    MedlinePlus

    ... of chronic liver disease, cirrhosis, viral hepatitis, and liver cancer make liver disease one of the 10 leading ... disease are decreasing, those for viral hepatitis and liver cancer are on the rise, both in the U.S. ...

  18. Generating an in vitro-in vivo correlation for metabolism and liver enrichment of a hepatitis C virus drug, faldaprevir, using a rat hepatocyte model (HepatoPac).

    PubMed

    Ramsden, Diane; Tweedie, Donald J; St George, Roger; Chen, Lin-Zhi; Li, Yongmei

    2014-03-01

    Hepatocytes provide an integrated model to study drug metabolism and disposition. As a result of a loss of polarity or a significant decrease in the expression of enzymes and transporters, suspended and sandwich-cultured hepatocytes have limitations in determining hepatocellular drug concentrations. Underprediction of the extent of glucuronidation is also a concern for these hepatocyte models. Faldaprevir is a hepatitis C virus protease inhibitor in late-stage development that has demonstrated significant liver enrichment in in vivo rat models based on quantitative whole-body autoradiography (QWBA) and liver-to-plasma area under-the-curve ratio. In bile duct cannulated rats, the primary biliary metabolite was a glucuronide. Owing to ethical concerns, it is difficult to assess liver enrichment in humans, and a lack of in vitro and in vivo correlation of glucuronidation has been reported. The current study was conducted to verify whether a hepatocyte model, rat HepatoPac, could overcome some of these limitations and provide validity for follow-up studies with human HepatoPac. With rat HepatoPac, liver enrichment values averaged 34-fold and were consistent with rat QWBA (26.8-fold) and in vivo data (42-fold). In contrast, liver enrichment in suspended hepatocytes was only 2.8-fold. Furthermore, the extent of faldaprevir glucuronidation in HepatoPac studies was in agreement with in vivo results, with glucuronidation as the major pathway (96%). Suspended rat hepatocytes did not generate the glucuronide or two key hydroxylated metabolites that were observed in vivo. Overall, our studies suggest that HepatoPac is a promising in vitro model to predict in vivo liver enrichment and metabolism, especially for glucuronidation, and has demonstrated superiority over suspended hepatocytes. PMID:24366905

  19. Enzyme-transporter interplay in the formation and clearance of abundant metabolites of faldaprevir found in excreta but not in circulation.

    PubMed

    Li, Yongmei; Zhou, Jin; Ramsden, Diane; Taub, Mitchell E; O'Brien, Drané; Xu, Jun; Busacca, Carl A; Gonnella, Nina; Tweedie, Donald J

    2014-03-01

    Faldaprevir is a hepatitis C virus protease inhibitor that effectively reduces viral load in patients. Since faldaprevir exhibits slow metabolism in vitro and low clearance in vivo, metabolism was expected to be a minor clearance pathway. The human [(14)C] absorption, distribution, metabolism, and excretion study revealed that two monohydroxylated metabolites (M2a and M2b) were the most abundant excretory metabolites in feces, constituting 41% of the total administered dose. To deconvolute the formation and disposition of M2a and M2b in humans and determine why the minor change in structure [the addition of 16 atomic mass units (amu)] produced chemical entities that were excreted and were not present in the circulation, multiple in vitro test systems were used. The results from these in vitro studies clarified the formation and clearance of M2a and M2b. Faldaprevir is metabolized primarily in the liver by CYP3A4/5 to form M2a and M2b, which are also substrates of efflux transporters (P-glycoprotein and breast cancer resistance protein). The role of transporters is considered important for M2a and M2b as they demonstrate low permeability. It is proposed that both metabolites are efficiently excreted via bile into feces and do not enter the systemic circulation to an appreciable extent. If these metabolites permeate to blood, they can be readily taken up into hepatocytes from the circulation by uptake transporters (likely organic anion transporting polypeptides). These results highlight the critical role of drug-metabolizing enzymes and multiple transporters in the process of the formation and clearance of faldaprevir metabolites. Faldaprevir metabolism also provides an interesting case study for metabolites that are exclusively excreted in feces but are of clinical relevance. PMID:24346834

  20. METABOLISM Wnt Signaling Regulates Hepatic Metabolism

    PubMed Central

    Liu, Hongjun; Fergusson, Maria M.; Wu, J. Julie; Rovira, Ilsa I.; Liu, Jie; Gavrilova, Oksana; Lu, Teng; Bao, Jianjun; Han, Donghe; Sack, Michael N.; Finkel, Toren

    2011-01-01

    The contribution of the Wnt pathway has been extensively characterized in embryogenesis, differentiation, and stem cell biology but not in mammalian metabolism. Here, using in vivo gain- and loss-of-function models, we demonstrate an important role for Wnt signaling in hepatic metabolism. In particular, β-Catenin, the downstream mediator of canonical Wnt signaling, altered serum glucose concentrations and regulated hepatic glucose production. β-catenin also modulated hepatic insulin signaling. Furthermore, β-catenin interacted with the transcription factor FoxO1 in livers from mice under starved conditions. The interaction of FoxO1 with β-catenin regulated the transcriptional activation of the genes encoding glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), the two rate-limiting enzymes in hepatic gluconeogenesis. Moreover, starvation induced the hepatic expression of mRNAs encoding different Wnt isoforms. In addition, nutrient deprivation appeared to favor the association of β-catenin with FoxO family members, rather than with members of the T cell factor of transcriptional activators. Notably, in a model of diet-induced obesity, hepatic deletion of β-catenin improved overall metabolic homeostasis. These observations implicate Wnt signaling in the modulation of hepatic metabolism and raise the possibility that Wnt signaling may play a similar role in the metabolic regulation of other tissues. PMID:21285411

  1. Quantifying rare, deleterious variation in 12 human cytochrome P450 drug-metabolism genes in a large-scale exome dataset

    PubMed Central

    Gordon, Adam S.; Tabor, Holly K.; Johnson, Andrew D.; Snively, Beverly M.; Assimes, Themistocles L.; Auer, Paul L.; Ioannidis, John P.A.; Peters, Ulrike; Robinson, Jennifer G.; Sucheston, Lara E.; Wang, Danxin; Sotoodehnia, Nona; Rotter, Jerome I.; Psaty, Bruce M.; Jackson, Rebecca D.; Herrington, David M.; O'Donnell, Christopher J.; Reiner, Alexander P.; Rich, Stephen S.; Rieder, Mark J.; Bamshad, Michael J.; Nickerson, Deborah A.

    2014-01-01

    The study of genetic influences on drug response and efficacy (‘pharmacogenetics’) has existed for over 50 years. Yet, we still lack a complete picture of how genetic variation, both common and rare, affects each individual's responses to medications. Exome sequencing is a promising alternative method for pharmacogenetic discovery as it provides information on both common and rare variation in large numbers of individuals. Using exome data from 2203 AA and 4300 Caucasian individuals through the NHLBI Exome Sequencing Project, we conducted a survey of coding variation within 12 Cytochrome P450 (CYP) genes that are collectively responsible for catalyzing nearly 75% of all known Phase I drug oxidation reactions. In addition to identifying many polymorphisms with known pharmacogenetic effects, we discovered over 730 novel nonsynonymous alleles across the 12 CYP genes of interest. These alleles include many with diverse functional effects such as premature stop codons, aberrant splicesites and mutations at conserved active site residues. Our analysis considering both novel, predicted functional alleles as well as known, actionable CYP alleles reveals that rare, deleterious variation contributes markedly to the overall burden of pharmacogenetic alleles within the populations considered, and that the contribution of rare variation to this burden is over three times greater in AA individuals as compared with Caucasians. While most of these impactful alleles are individually rare, 7.6–11.7% of individuals interrogated in the study carry at least one newly described potentially deleterious alleles in a major drug-metabolizing CYP. PMID:24282029

  2. Gene expression profiles of hepatic cell-type specific marker genes in progression of liver fibrosis

    PubMed Central

    Takahara, Yoshiyuki; Takahashi, Mitsuo; Wagatsuma, Hiroki; Yokoya, Fumihiko; Zhang, Qing-Wei; Yamaguchi, Mutsuyo; Aburatani, Hiroyuki; Kawada, Norifumi

    2006-01-01

    AIM: To determine the gene expression profile data for the whole liver during development of dimethylni-trosamine (DMN)-induced hepatic fibrosis. METHODS: Marker genes were identified for different types of hepatic cells, including hepatic stellate cells (HSCs), Kupffer cells (including other inflammatory cells), and hepatocytes, using independent temporal DNA microarray data obtained from isolated hepatic cells. RESULTS: The cell-type analysis of gene expression gave several key results and led to formation of three hypotheses: (1) changes in the expression of HSC-specific marker genes during fibrosis were similar to gene expression data in in vitro cultured HSCs, suggesting a major role of the self-activating characteristics of HSCs in formation of fibrosis; (2) expression of mast cell-specific marker genes reached a peak during liver fibrosis, suggesting a possible role of mast cells in formation of fibrosis; and (3) abnormal expression of hepatocyte-specific marker genes was found across several metabolic pathways during fibrosis, including sulfur-containing amino acid metabolism, fatty acid metabolism, and drug metabolism, suggesting a mechanistic relationship between these abnormalities and symptoms of liver fibrosis. CONCLUSION: Analysis of marker genes for specific hepatic cell types can identify the key aspects of fibrogenesis. Sequential activation of inflammatory cells and the self-supporting properties of HSCs play an important role in development of fibrosis. PMID:17072980

  3. Protect Yourself from Hepatitis

    MedlinePlus

    ... develop yellowish eyes and skin. All the hepatitis viruses can cause acute, or short-term, hepatitis. Some can also cause chronic hepatitis, in which the infection lasts a long time, sometimes for your whole life. Chronic hepatitis can eventually lead to scarring of ...

  4. Hepatic osteodystrophy.

    PubMed

    Gatta, Angelo; Verardo, Alberto; Di Pascoli, Marco; Giannini, Sandro; Bolognesi, Massimo

    2014-09-01

    Metabolic disturbances of bone are frequent in patients with chronic liver disease. The prevalence of osteoporosis among patients with advanced chronic liver disease is reported between 12% and 55%; it is higher in primary biliary cirrhosis. All patients with advanced liver disease should be screened for osteoporosis with a densitometry, especially if the etiology is cholestatic and in the presence of other risk factors. Clinical relevance of hepatic osteodystrophy increases after liver transplantation. After liver transplant, a rapid loss of bone mineral density can be detected in the first 6 months, followed by stabilization and slight improvement of the values. At the time of transplantation, bone density values are very important prognostic factors. Therapy of hepatic osteodystrophy is based primarily on the control of risk factors: cessation of tobacco and alcohol assumption, reduction of caffeine ingestion, exercise, supplementation of calcium and vitamin D, limitation of drugs such as loop diuretics, corticosteroids, cholestyramine. Bisphosphonates have been proposed for the therapy of osteoporosis in patients with liver disease, particularly after liver transplantation. The possible side effects of oral administration of bisphosphonates, such as the occurrence of esophageal ulcerations, are of particular concern in patients with liver cirrhosis and portal hypertension, due to the risk of gastrointestinal hemorrhage from ruptured esophageal varices, although this risk is probably overestimated. PMID:25568651

  5. [Hepatic encephalopathy].

    PubMed

    Festi, Davide; Marasco, Giovanni; Ravaioli, Federico; Colecchia, Antonio

    2016-07-01

    Hepatic encephalopathy (HE) is a common complication of liver cirrhosis and it can manifest with a broad spectrum of neuropsychiatric abnormalities of varying severity, acuity and time course with important clinical implications. According to recent guidelines, HE has been classified into different types, depending on the severity of hepatic dysfunction, the presence of porto-systemic shunts and the number of previous episodes or persistent manifestations. From a clinical point of view, HE can be recognized as unimpaired, covert (that deals with minimal and grade 1 according to the grading of mental state), and overt (that is categorized from grade 2 to grade 4). Different and only partially known pathogenic mechanisms have been identified, comprising ammonia, inflammatory cytokines, benzodiazepine-like compounds and manganese deposition. Different therapeutic strategies are available for treating HE, in particular the overt HE, since covert HE needs to be managed case by case. Recognition and treatment of precipitating factors represent fundamental part of the management. The more effective treatments, which can be performed separately or combined, are represented by non-absorbable disaccharides (lactulose and lactitol) and the topic antibiotic rifaximin; other possible therapies, mainly used in patients non responders to previous treatments, are represented by branched chain amino acids and metabolic ammonia scavengers. PMID:27571468