An evaluation of the cytochrome P450 induction potential of pantoprazole in primary human hepatocytes

Masubuchi, Noriko; Li, Albert P.; Okazaki, Osamu

doi:10.1016/s0009-2797(98)00031-3

Cited by 42 publications

(23 citation statements)

References 19 publications

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“…The known inducers of CYP3A4 in human hepatocytes-rifampin (Li et al, 1995;Roymans et al, 2004;Shou et al, 2008), carbamazepine (Shou et al, 2008), omeprazole (Masubuchi et al, 1998), phenobarbital (Shou et al, 2008), and phenytoin (Luo et al, 2002)-were found to cause concentration-dependent induction of LIPA metabolism. The observation of omeprazole as a less potent inducer of CYP3A4 than rifampin is consistent with historical data in our laboratory (unpublished data) and others (Roymans et al, 2004) using testosterone 6␤-hydroxylation as the activity endpoint.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Luciferin-Isopropyl Acetal as a CYP3A4 Substrate for Human Hepatocytes: Effects of Organic Solvents, Cytochrome P450 (P450) Inhibitors, and P450 Inducers

Li¹

2009

Drug Metab Dispos

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ABSTRACT:This study represents the first report on the characterization of luciferin-isopropyl acetal (LIPA) as a CYP3A4 substrate in human hepatocytes. LIPA metabolism by human hepatocytes was found to be linear with time up to 120 min and followed Michaelis-Menten kinetics, with apparent K m value of 15 M and V max of 41 pmol/ min/million hepatocytes for the hepatocytes used in the study. The nonspecific cytochrome P450 (P450) inhibitor 1-aminobenzotriazole (ABT) and the CYP3A4-selective inhibitor ketoconazole (KTZ) caused concentration-dependent inhibition of LIPA metabolism, with more than 50% inhibition observed at the lowest concentrations evaluated of 7.8 M (ABT) and 0.78 M (KTZ), and near 100% inhibition observed at higher concentrations. Substantially lower inhibitory effects were observed for the non-CYP3A4 inhibitors diethyldithiocarbamate, furafylline, omeprazole, orphenadrine, sulfaphenazole, and quinidine. The commonly used organic solvents-acetonitrile, dimethyl sulfoxide (DMSO), and methanolwere found to inhibit LIPA metabolism, with approximately 50% inhibition at concentrations of 5, 1.25, and 5% (by volume), respectively. The comparatively higher inhibitory effects of DMSO relative to that for acetonitrile and methanol on LIPA metabolism were consistent with its known CYP3A4 inhibitory effects reported by others. LIPA metabolism in human hepatocytes was found to be induced by the treatment of human hepatocytes with the prototypical CYP3A4 inducers rifampin, carbamazepine, omeprazole, phenobarbital, and phenytoin but not by the CYP1A2 inducer 3-methylcholanthrene. Although the selectivity toward CYP3A4 needs to be definitively evaluated using cDNA-expressed P450 isoforms, the results suggest that LIPA is a suitable substrate to be used with human hepatocytes for the evaluation of CYP3A4 activities.Cytochrome P450 (P450) is an important family of enzymes responsible for xenobiotic metabolism. Of the multiple isoforms, P450 isoform 3A4 (CYP3A4) is the most abundant of the isoforms in the human liver. CYP3A4 has been found to be responsible for the metabolism of a large variety of exogenous and endogenous substrates (Guengerich, 2006;Zhou, 2008). In drug development, there is a need to evaluate the inhibitory and inductive potential of drug candidates toward CYP3A4 to estimate their drug-drug interaction potential with the myriad drugs that are substrates of this important P450 isoform (Lin and Lu, 1998;Li, 2001).Quantification of CYP3A4 activity of an enzyme system (e.g., liver microsomes, hepatocytes) is performed by incubation with a CYP3A4-selective substrate, followed by quantification of the metabolites formed. The most commonly used substrates are testosterone and midazolam, with 6␤-hydroxytestosterone (Chauret et al., 1998;Easterbrook et al., 2001) and 1Ј-hydroxymidazolam (Emoto andIwasaki, 2007), respectively, as the CYP3A4-mediated metabolites (Guengerich, 2006). Quantification of these metabolites requires the use of high-performance liquid chromatography (HPLC), often facilitated by ma...

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Section: Discussionmentioning

confidence: 99%

Evaluation of Luciferin-Isopropyl Acetal as a CYP3A4 Substrate for Human Hepatocytes: Effects of Organic Solvents, Cytochrome P450 (P450) Inhibitors, and P450 Inducers

Li¹

2009

Drug Metab Dispos

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“…5,6) Rifampicin is a potent inducer of CYP3A in primary cultures of human hepatocytes, [7][8][9] and omeprazole is a potent inducer of CYP1A in primary cultures of human hepatocytes. [10][11][12][13] There have been reports on the usefulness of the quantitative real-time reverse-transcription polymerase chain reaction method (RT PCR) for the analysis of human CYP1A1 and CYP3A4 mRNA expression in primary cultures of human hepatocytes 10) and mouse cytochrome P450 mRNA expression in mouse liver. 14) However, methods for the quantitative, high-throughput, real-time RT PCR of human ％ CO 2 and 95％ air at 37°C.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Gene Induction of Drug-Metabolizing Enzymes and Transporters in Primary Culture of Human Hepatocytes Using High-Sensitivity Real-Time Reverse Transcription PCR

et al. 2002

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In the present study, the induction of drug-metabolizing enzymes and transporters was evaluated by analyzing mRNA expression in human hepatocytes after exposure to various compounds. The compounds tested included typical enzyme inducers, rifampicin and omeprazole, and controls. All experiments were performed in the presence of 0.1％ DMSO. Analysis was performed by the real-time reverse-transcription polymerase chain reaction method (RT PCR) in the presence of TaqMan probes using an ABI PRISM 7700 Sequence Detector system. A new analytic method to quantify mRNA levels in small numbers of human hepatocytes has been developed for phase I enzymes, phase II enzymes, and transporters. The levels of CYP1A1, CYP2B6, CYP2C8, CYP3A4, CYP3A5, ADH3, and ABCG1 mRNA in human hepatocytes increased after exposure to rifampicin. The levels of CYP1A1, CYP2B6, CYP3A4, CYP3A5, and ABCG1 mRNA recovered after a change to media without rifampicin. The levels of CYP1A1, CYP1A2, CYP1B1, ALDH3, and ALDH6 mRNA increased after exposure to omeprazole, and recovered after a change to media without omeprazole. On the other hand, the levels of ADH3 and ABCB4 mRNA decreased after exposure to omeprazole, and recovered after a change to media without omeprazole. In conclusion, these results demonstrate the applicability of quantitative real-time RT PCR to the evaluation of the gene induction and recovery of drug-metabolizing enzymes and transporters after exposure to drugs in human hepatocytes.

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“…Both LPZ 22) and BNF 23) are known to be typical inducers of CYP1A enzymes in human hepatocytes. Pretreatment of Hep G2 cells with LPZ (25 and 50 µM) increased ER O-deethylase activity by 4.2-to 4.8-fold that of the control cells pretreated with the vehicle (0.5% DMSO) only.…”

Section: Resultsmentioning

confidence: 99%

Effects of Pretreatment of Hep G2 Cells with .BETA.-Naphthoflavone on Cytotoxicity of Propranolol and its Active Metabolite 4-Hydroxypropranolol

Miyano

Motoyama

Fukuoka

et al. 2003

JOURNAL OF HEALTH SCIENCE

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Cytotoxicities of propranolol (PL) and its active metabolite, 4-hydroxypropranolol (4-OH-PL), were examined in a human hepatoma cell line, Hep G2. Hep G2 cells were cultured in the presence of β-naphthoflavone (BNF, 25 or 50 µM), lansoprazole (LPZ, 25 or 50 µM) or 0.5% dimethylsulfoxide (vehicle) for 48 hr. The cells were harvested, and microsomal and cytosolic fractions were prepared by differential centrifugation methods. Various enzyme activities were determined as follows: microsomal 7-ethoxyresorufin (ER) O-deethylation as a CYP1A1 index, microsomal phenacetin (PN) O-deethylation as a CYP1A2 index, microsomal and cytosolic p-nitrophenyl acetate (NPA) hydrolysis as a carboxylesterase index and cytosolic 4-OH-PL sulfation as a sulfotransferase index. The pretreatment of Hep G2 cells with LPZ or BNF increased microsomal ER O-deethylase activities, and the potency of BNF was much higher than that of LPZ. Cytosolic 4-OH-PL sulfation was also elevated by the pretreatment with BNF but not with LPZ. Microsomal PN O-deethylase activity was not detectable in either the control or BNFpretreated group under the conditions used. Microsomal and cytosolic NPA hydrolase activities were similar between the control and the BNF-pretreated groups. Cytotoxicities of PL and 4-OH-PL were attenuated in BNFpretreated Hep G2 cells compared to non-pretreated Hep G2 cells. These results suggest that increased activities of microsomal CYP1A1 and cytosolic sulfotransferases by pretreatment with BNF may contribute to the attenuating the cytotoxicity of PL and 4-OH-PL in Hep G2 cells, at least in part.

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An evaluation of the cytochrome P450 induction potential of pantoprazole in primary human hepatocytes

Cited by 42 publications

References 19 publications

Evaluation of Luciferin-Isopropyl Acetal as a CYP3A4 Substrate for Human Hepatocytes: Effects of Organic Solvents, Cytochrome P450 (P450) Inhibitors, and P450 Inducers

Evaluation of Luciferin-Isopropyl Acetal as a CYP3A4 Substrate for Human Hepatocytes: Effects of Organic Solvents, Cytochrome P450 (P450) Inhibitors, and P450 Inducers

Evaluation of Gene Induction of Drug-Metabolizing Enzymes and Transporters in Primary Culture of Human Hepatocytes Using High-Sensitivity Real-Time Reverse Transcription PCR

Effects of Pretreatment of Hep G2 Cells with .BETA.-Naphthoflavone on Cytotoxicity of Propranolol and its Active Metabolite 4-Hydroxypropranolol

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