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Kharasch ED, Lenze EJ. Pharmacogenetic Influence on Stereoselective Steady-State Disposition of Bupropion. Drug Metab Dispos 2024; 52:455-466. [PMID: 38467432 PMCID: PMC11023817 DOI: 10.1124/dmd.124.001697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/02/2024] [Accepted: 03/07/2024] [Indexed: 03/13/2024] Open
Abstract
Bupropion is used for treating depression, obesity, and seasonal affective disorder, and for smoking cessation. Bupropion is commonly prescribed, but has complex pharmacokinetics and interindividual variability in metabolism and bioactivation may influence therapeutic response, tolerability, and safety. Bupropion is extensively and stereoselectively metabolized, the metabolites are pharmacologically active, and allelic variation in cytochrome P450 (CYP) 2B6 affects clinical hydroxylation of single-dose bupropion. Genetic effects on stereoselective disposition of steady-state bupropion are not known. In this preplanned secondary analysis of a prospective, randomized, double-blinded, crossover study which compared brand and generic bupropion XL 300 mg drug products, we measured steady-state enantiomeric plasma and urine parent bupropion and primary and secondary metabolite concentrations. This investigation evaluated the influence of genetic polymorphisms in CYP2B6, CYP2C19, and P450 oxidoreductase on the disposition of Valeant Pharmaceuticals Wellbutrin brand bupropion in 67 participants with major depressive disorder. We found that hydroxylation of both bupropion enantiomers was lower in carriers of the CYP2B6*6 allele and in carriers of the CYP2B6 516G>T variant, with correspondingly greater bupropion and lesser hydroxybupropion plasma concentrations. Hydroxylation was 25-50% lower in CYP2B6*6 carriers and one-third to one-half less in 516T carriers. Hydroxylation of the bupropion enantiomers was comparably affected by CYP2B6 variants. CYP2C19 polymorphisms did not influence bupropion plasma concentrations or hydroxybupropion formation but did influence the minor pathway of 4'-hydroxylation of bupropion and primary metabolites. P450 oxidoreductase variants did not influence bupropion disposition. Results show that CYP2B6 genetic variants affect steady-state metabolism and bioactivation of Valeant brand bupropion, which may influence therapeutic outcomes. SIGNIFICANCE STATEMENT: Bupropion, used for depression, obesity, and smoking cessation, undergoes metabolic bioactivation, with incompletely elucidated interindividual variability. We evaluated cytochrome P450 (CYP) 2B6, CYP2C19 and P450 oxidoreductase genetic variants and steady-state bupropion and metabolite enantiomers disposition. Both enantiomers hydroxylation was lower in CYP2B6*6 and CYP2B6 516G>T carriers, with greater bupropion and lesser hydroxybupropion plasma concentrations. CYP2C19 polymorphisms did not affect bupropion or hydroxybupropion but did influence minor 4'-hydroxylation of bupropion and primary metabolites. CYP2B6 variants affect steady-state bupropion bioactivation, which may influence therapeutic outcomes.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Duke University, Durham, North Carolina (E.D.K.); Bermaride, LLC (E.D.K.); and Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri (E.J.L.)
| | - Eric J Lenze
- Department of Anesthesiology, Duke University, Durham, North Carolina (E.D.K.); Bermaride, LLC (E.D.K.); and Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri (E.J.L.)
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2
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Eum S, Sayre F, Lee AM, Stingl JC, Bishop JR. Association of CYP2B6 genetic polymorphisms with bupropion and hydroxybupropion exposure: A systematic review and meta-analysis. Pharmacotherapy 2021; 42:34-44. [PMID: 34752647 DOI: 10.1002/phar.2644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/16/2021] [Accepted: 10/17/2021] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Bupropion is metabolized to its active metabolite, hydroxybupropion (HB), by the genetically polymorphic cytochrome P450 2B6 (CYP2B6) enzyme. Despite its significant role in bupropion metabolism, the magnitude of the impact of CYP2B6 genotype on the exposure of bupropion has not been quantified. OBJECTIVES A systematic review and meta-analysis was conducted to quantify the association of bupropion and HB exposure with CYP2B6 variant alleles and genotype-defined metabolizer phenotypes. METHODS MEDLINE, EMBASE, Web of Science, Scifinder, PsycINFO, and CENTRAL were screened to identify studies that met the following inclusion criteria (search updated on February 2021): (1) area under the plasma drug concentration-time curve (AUC) of bupropion and/or HB in relation to CYP2B6 genotypes was studied, and (2) study participants were genotyped for common CYP2B6 variant alleles including at least CYP2B6*6. The Newcastle Ottawa Scale was used to assess risk of bias in each included study. The ratio of means (RoM) between CYP2B6 genotype or genotype-defined phenotype groups for bupropion exposure was calculated for each study and combined in a meta-analysis. RESULTS Eleven studies met the inclusion criteria for this systematic review, and 10 (including N = 413 participants) were included in the meta-analysis. All 10 studies involved healthy adult volunteers, where other medications were not allowed. The AUCs of HB and the active moiety (bupropion + HB) were significantly reduced in CYP2B6*6 carriers compared with the non-carriers (HB: RoM 0.77, 95% CI 0.71-0.83; active moiety: RoM 0.81, 95% CI 0.75-0.88). Both CYP2B6 poor and intermediate metabolizers had significantly decreased exposures to HB and the active moiety than normal metabolizers. CONCLUSION The CYP2B6*6 allele and genotype-determined CYP2B6 poor and intermediate metabolizer phenotypes are associated with significantly lower exposures to HB and the total active moiety. The findings of this study suggest opportunities to further study precision dosing strategies for bupropion therapy based on CYP2B6 genotype.
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Affiliation(s)
- Seenae Eum
- Department of Pharmacogenomics, School of Pharmacy, Shenandoah University, Fairfax, Virginia, USA
| | - Franklin Sayre
- Librarian Department, Thompson Rivers University, Kamloops, British Columbia, Canada
| | - Adam M Lee
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia C Stingl
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Aachen, Germany
| | - Jeffrey R Bishop
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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3
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Stäuble CK, Lampert ML, Mikoteit T, Hatzinger M, Hersberger KE, Meyer Zu Schwabedissen HE. Nonresponse to high-dose bupropion for depression in a patient carrying CYP2B6*6 and CYP2C19*17 variants: a case report. Pharmacogenomics 2020; 21:1145-1150. [PMID: 33124517 DOI: 10.2217/pgs-2020-0087] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report the case of a patient with major depression treated with high-dose bupropion due to prior detected subtherapeutic blood concentrations at standard dosing. Pharmacogenetic panel testing identified the patient as a carrier of the CYP2B6*6 allele, which has been associated with reduced bupropion metabolism and decreased concentrations of the pharmacologically active metabolite hydroxybupropion. Interestingly, we also found the patient to be homozygous for the CYP2C19*17 allele, predicting an ultra rapid metabolizer phenotype. We propose a combined effect of the detected CYP2C19 and CYP2B6 genetic variants on bupropion metabolism. This case underlines the potential benefit of pre-emptive pharmacogenotyping but also the yet still fragmentary evidence making precise pharmacogenotype guided antidepressant selection and dosing challenging.
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Affiliation(s)
- Céline K Stäuble
- Biopharmacy, Department of Pharmaceutical Sciences, University of Basel, 4056, Basel, Switzerland.,Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, 4001, Basel, Switzerland
| | - Markus L Lampert
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, 4001, Basel, Switzerland.,Institute of Hospital Pharmacy, Solothurner Spitäler, 4600, Olten, Switzerland
| | - Thorsten Mikoteit
- Psychiatric Services Solothurn, Solothurner Spitäler, 4503, Solothurn, Switzerland
| | - Martin Hatzinger
- Psychiatric Services Solothurn, Solothurner Spitäler, 4503, Solothurn, Switzerland
| | - Kurt E Hersberger
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, 4001, Basel, Switzerland
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4
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Gaebler AJ, Schneider KL, Stingl JC, Paulzen M. Subtherapeutic bupropion and hydroxybupropion serum concentrations in a patient with CYP2C19*1/*17 genotype suggesting a rapid metabolizer status. THE PHARMACOGENOMICS JOURNAL 2020; 20:840-844. [PMID: 32475982 DOI: 10.1038/s41397-020-0169-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 05/09/2020] [Accepted: 05/18/2020] [Indexed: 11/09/2022]
Abstract
Bupropion is hydroxylated to its primary active metabolite hydroxybupropion by cytochrome P450 enzyme CYP2B6. In vitro data suggest the existence of alternative hydroxylation pathways mediated by the highly polymorphic enzyme CYP2C19. However, the impact of its genetic variants on bupropion metabolism in vivo is still under investigation. We report the case of a 28-year-old male Caucasian outpatient suffering from major depressive disorder who did not respond to a treatment with bupropion. Therapeutic drug monitoring revealed very low serum concentrations of both bupropion and hydroxybupropion. Genotyping identified a heterozygous status for the gain-of-function allele with the genotype CYP2C19*1/*17 predicting enhanced enzymatic activity. The present case shows a reduced bupropion efficacy, which may be explained by a reduced active moiety of bupropion and its active metabolite hydroxybupropion, due to alternative hydroxylation pathways mediated by CYP2C19 in an individual with CYP2C19 rapid metabolizer status. The case report thus illustrates the clinical relevance of therapeutic drug monitoring in combination with pharmacogenetics diagnostics for a personalized treatment approach.
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Affiliation(s)
- Arnim Johannes Gaebler
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Germany. .,JARA-Translational Brain Medicine, Aachen, Germany.
| | - Katharina Luise Schneider
- Research Division, Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany.,Centre for Translational Medicine, Medical Faculty of the University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany
| | - Julia Carolin Stingl
- Institute of Clinical Pharmacology, Medical Faculty, RWTH Aachen, Wendlingweg 2, 52074, Aachen, Germany
| | - Michael Paulzen
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Germany.,JARA-Translational Brain Medicine, Aachen, Germany.,Alexianer Hospital Aachen, Alexianergraben 33, 52062, Aachen, Germany
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5
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Wang PF, Neiner A, Kharasch ED. Stereoselective Bupropion Hydroxylation by Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase Genetic Variants. Drug Metab Dispos 2020; 48:438-445. [PMID: 32238417 DOI: 10.1124/dmd.119.090407] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Bioactivation of the antidepressant and smoking cessation drug bupropion is catalyzed predominantly by CYP2B6. The metabolite hydroxybupropion derived from t-butylhydroxylation is considered to contribute to the antidepressant and smoking-cessation effects of the parent drug. Bupropion hydroxylation is the canonical in vitro and in vivo probe for CYP2B6 activity. P450 also requires obligate partnership with P450 oxidoreductase (POR). Human CYP2B6 and POR genes are highly polymorphic. Some CYP2B6 variants affect bupropion disposition. This investigation evaluated the influence of several human CYP2B6 and POR genetic variants on stereoselective bupropion metabolism, using an insect cell coexpression system containing CYP2B6, POR, and cytochrome b 5 Based on intrinsic clearances (Clints), relative activities for S,S-hydroxybupropion formation were in the order CYP2B6.4 > CYP2B6.1 > CYP2B6.17 > CYP2B6.5 > CYP2B6.6 ≈ CYP2B6.26 ≈ CYP2B6.19 > CYP2B6.7 > CYP2B6.9 > > CYP2B6.16 and CYP2B6.18; relative activities for R,R-hydroxybupropion formation were in the order CYP2B6.17 > CYP2B6.4 > CYP2B6.1 > CYP2B6.5 ≈ CYP2B6.19 ≈ CYP2B6.26 > CYP2B6.6 > CYP2B6.7 ≈ CYP2B6.9 > > CYP2B6.16 and CYP2B6.18. Bupropion hydroxylation was not influenced by POR variants. CYP2B6-catalyzed bupropion hydroxylation is stereoselective. Though Vmax and Km varied widely among CYP2B6 variants, stereoselectivity was preserved, reflected by similar Clint(S,S-hydroxybupropion)/Clint(R,R-hydroxybupropion) ratios (1.8-2.9), except CYP2B6.17, which was less enantioselective. Established concordance between human bupropion hydroxylation in vitro and in vivo, together with these new results, suggests additional CYP2B6 variants may influence human bupropion disposition. SIGNIFICANCE STATEMENT: Bupropion pharmacokinetics, metabolism, and clinical effects are affected by the CYP2B6*6 polymorphism. Other expressed CYP2B6 polymorphisms had diminished (*5, *6, *7, *9, *19, *26) or defective (*16, *18) in vitro bupropion hydroxylation. P450 oxidoreductase genetic variants had no effect on metabolism, suggesting no clinical consequence of this polymorphism. These CYP2B6 polymorphisms may portend diminished in vivo bupropion hydroxylation and predict additional clinically important variant alleles.
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Affiliation(s)
- Pan-Fen Wang
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Alicia Neiner
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Evan D Kharasch
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
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6
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Ozdemir F, Oz MD, Suzen HS. A Novel PCR-RFLP Method for Detection of POR*28 Polymorphism and its Genotype/Allele Frequencies in a Turkish Population. Curr Drug Metab 2019; 20:845-851. [PMID: 31518218 DOI: 10.2174/1389200220666190913121052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/15/2019] [Accepted: 09/02/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND The Cytochrome P450 (CYP) enzymes are involved in the metabolism of many endogenous and exogenous substances. They need electrons for their activity. CYP mediated oxidation reactions require cytochrome oxidoreductase (POR) as an electron donor. A common genetic variation identified in the coding region of POR gene (POR*28) leads to an alteration in POR activity by causing amino acid change. The current study aimed to determine the allele and genotype frequencies of POR*28 in a healthy Turkish population by using a novel genotyping assay. METHODS A novel PCR-RFLP assay was developed for the detection of POR*28 (rs1057868) polymorphism and the obtained frequencies were compared with the data established in various ethnic groups. RESULTS Genotypic analysis revealed that of 209 healthy, unrelated individuals tested for POR*28 polymorphism, 55.5% of the studied subjects were homozygous for the CC genotype, 34.9% were heterozygous for the CT genotype and 9.6% were homozygous for the TT genotype. The allele frequencies were 0.73 (C) and 0.27 (T). The present results were in accordance with the Hardy- Weinberg equilibrium. The distribution of POR*28 allele varies between populations. The frequency of the T allele among members of the Turkish population was similar to frequencies in Caucasian populations but was lower than in Japanese and Chinese populations. CONCLUSIONS In this study, a novel method was developed, which could be applied easily in every laboratory for the genotyping of POR *28 polymorphism. The developed genotyping method and documented allele frequencies may have potential in understanding and predicting the variations in drug response/adverse reactions in pharmacotherapy and susceptibility to diseases in POR-mediated metabolism reactions.
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Affiliation(s)
- Fezile Ozdemir
- Department of Forensic Toxicology, Institute of Forensic Sciences, Ankara University, Ankara, 06590, Turkey
| | - Merve Demirbugen Oz
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Ankara University, Ankara, 06560, Turkey
| | - Hilat S Suzen
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Ankara University, Ankara, 06560, Turkey
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7
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Stereoselective Ketamine Metabolism by Genetic Variants of Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase. Anesthesiology 2019; 129:756-768. [PMID: 30085944 DOI: 10.1097/aln.0000000000002371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Human ketamine N-demethylation to norketamine in vitro at therapeutic concentrations is catalyzed predominantly by the cytochrome P4502B6 isoform (CYP2B6). The CYP2B6 gene is highly polymorphic. CYP2B6.6, the protein encoded by the common variant allele CYP2B6*6, exhibits diminished ketamine metabolism in vitro compared with wild-type CYP2B6.1. The gene for cytochrome P450 oxidoreductase (POR), an obligatory P450 coenzyme, is also polymorphic. This investigation evaluated ketamine metabolism by genetic variants of human CYP2B6 and POR. METHODS CYP2B6 (and variants), POR (and variants), and cytochrome b5 (wild-type) were coexpressed in a cell system. All CYP2B6 variants were expressed with wild-type POR and b5. All POR variants were expressed with wild-type CYP2B6.1 and b5. Metabolism of R- and S-ketamine enantiomers, and racemic RS-ketamine to norketamine enantiomers, was determined using stereoselective high-pressure liquid chromatography-mass spectrometry. Michaelis-Menten kinetic parameters were determined. RESULTS For ketamine enantiomers and racemate, metabolism (intrinsic clearance) was generally wild-type CYP2B6.1 > CYP2B6.4 > CYP2B6.26, CYP2B6.19, CYP2B6.17, CYP2B6.6 > CYP2B6.5, CYP2B6.7 > CYP2B6.9. CYP2B6.16 and CYP2B6.18 were essentially inactive. Activity of several CYP2B6 variants was less than half that of CYP2B6.1. CYP2B6.9 was 15 to 35% that of CYP2B6.1. The order of metabolism was wild-type POR.1 > POR.28, P228L > POR.5. CYP2B6 variants had more influence than POR variants on ketamine metabolism. Neither CYP2B6 nor POR variants affected the stereoselectivity of ketamine metabolism (S > R). CONCLUSIONS Genetic variants of CYP2B6 and P450 oxidoreductase have diminished ketamine N-demethylation activity, without affecting the stereoselectivity of metabolism. These results suggest candidate genetic polymorphisms of CYP2B6 and P450 oxidoreductase for clinical evaluation to assess consequences for ketamine pharmacokinetics, elimination, bioactivation, and therapeutic effects.
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8
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Bloom AJ, Wang P, Kharasch ED. Nicotine oxidation by genetic variants of CYP2B6 and in human brain microsomes. Pharmacol Res Perspect 2019; 7:e00468. [PMID: 30906561 PMCID: PMC6411694 DOI: 10.1002/prp2.468] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/20/2019] [Indexed: 11/16/2022] Open
Abstract
Common variation in the CYP2B6 gene, encoding the cytochrome P450 2B6 enzyme, is associated with substrate-specific altered clearance of multiple drugs. CYP2B6 is a minor contributor to hepatic nicotine metabolism, but the enzyme has been proposed as relevant to nicotine-related behaviors because of reported CYP2B6 mRNA expression in human brain tissue. Therefore, we hypothesized that CYP2B6 variants would be associated with altered nicotine oxidation, and that nicotine metabolism by CYP2B6 would be detected in human brain microsomes. We generated recombinant enzymes in insect cells corresponding to nine common CYP2B6 haplotypes and demonstrate genetically determined differences in nicotine oxidation to nicotine iminium ion and nornicotine for both (S) and (R)-nicotine. Notably, the CYP2B6.6 and CYP2B6.9 variants demonstrated lower intrinsic clearance relative to the reference enzyme, CYP2B6.1. In the presence of human brain microsomes, along with nicotine-N-oxidation, we also detect nicotine oxidation to nicotine iminium ion. However, unlike N-oxidation, this activity is NADPH independent, does not follow Michaelis-Menten kinetics, and is not inhibited by NADP or carbon monoxide. Furthermore, metabolism of common CYP2B6 probe substrates, methadone and ketamine, is not detected in the presence of brain microsomes. We conclude that CYP2B6 metabolizes nicotine stereoselectively and common CYP2B6 variants differ in nicotine metabolism activity, but did not find evidence of CYP2B6 activity in human brain.
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Affiliation(s)
- Adam Joseph Bloom
- Department of Psychiatry and AnesthesiologyWashington UniversitySt. LouisMissouri
| | - Pan‐Fen Wang
- Department of AnesthesiologyDuke University School of MedicineDurhamNorth Carolina
| | - Evan D. Kharasch
- Department of AnesthesiologyDuke University School of MedicineDurhamNorth Carolina
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9
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Kharasch ED, Crafford A. Common Polymorphisms of CYP2B6 Influence Stereoselective Bupropion Disposition. Clin Pharmacol Ther 2018; 105:142-152. [PMID: 29756345 DOI: 10.1002/cpt.1116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022]
Abstract
Bupropion hydroxylation is a bioactivation and metabolic pathway, and the standard clinical CYP2B6 probe. This investigation determined the influence of CYP2B6 allelic variants on clinical concentrations and metabolism of bupropion enantiomers. Secondary objectives evaluated the influence of CYP2C19 and P450 oxidoreductase variants. Healthy volunteers in specific cohorts (CYP2B6*1/*1, CYP2B6*1/*6, CYP2B6*6/*6, and also CYP2B6*4 carriers) received single-dose oral bupropion. Plasma and urine bupropion and hydroxybupropion was quantified. Subjects were also genotyped for CYP2C19 and P450 oxidoreductase variants. Hydroxylation of both bupropion enantiomers, assessed by plasma hydroxybupropion/bupropion AUC ratios and urine hydroxybupropion formation clearances, was lower in CYP2B6*6/*6 but not CYP2B6*1/*6 compared with CYP2B6*1/*1 genotypes, and numerically greater in CYP2B6*4 carriers. CYP2C19 and P450 oxidoreductase variants did not influence bupropion enantiomers hydroxylation or plasma concentrations. The results show that clinical hydroxylation of both bupropion enantiomers was equivalently influenced by CYP2B6 allelic variation. CYP2B6 polymorphisms affect S-bupropion bioactivation, which may affect therapeutic outcomes.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, Missouri, USA.,Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University in St. Louis, St. Louis, Missouri, USA
| | - Amanda Crafford
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
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10
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Miller WL. Steroidogenesis: Unanswered Questions. Trends Endocrinol Metab 2017; 28:771-793. [PMID: 29031608 DOI: 10.1016/j.tem.2017.09.002] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 01/06/2023]
Abstract
Until the mid-1980s studies of steroidogenesis largely depended on identifying steroid structures and measuring steroid concentrations in body fluids. The molecular biology revolution radically revolutionized studies of steroidogenesis with the cloning of known steroidogenic enzymes, by identifying novel factors, and delineating the genetic basis of known and newly discovered diseases. Unfortunately, this dramatic success has led many young research-oriented endocrinologists to regard steroidogenesis as a 'solved area'. However, many important and exciting questions remain, especially concerning the mechanisms of cholesterol delivery to the steroidogenic machinery, the biochemistry of androgen synthesis, the regulation and biological role of adrenarche, fetal adrenal development and involution, the roles of steroids made in 'extraglandular' cells, and the search for genetic disorders. This review outlines some of these questions, but this list is necessarily incomplete.
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Affiliation(s)
- Walter L Miller
- Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA 94143-0556, USA.
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11
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Polymorphisms in cytochrome P450 oxidoreductase and its effect on drug metabolism and efficacy. Pharmacogenet Genomics 2017; 27:337-346. [DOI: 10.1097/fpc.0000000000000297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Gao J, Tian X, Zhou J, Cui MZ, Zhang HF, Gao N, Wen Q, Qiao HL. From Genotype to Phenotype: Cytochrome P450 2D6-Mediated Drug Clearance in Humans. Mol Pharm 2017; 14:649-657. [DOI: 10.1021/acs.molpharmaceut.6b00920] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jie Gao
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Xin Tian
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Jun Zhou
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Ming-Zhu Cui
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Hai-Feng Zhang
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Na Gao
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Qiang Wen
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Hai-Ling Qiao
- Institute
of Clinical Pharmacology, Zhengzhou University, Zhengzhou, Henan 450052, China
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13
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Tanner JA, Prasad B, Claw KG, Stapleton P, Chaudhry A, Schuetz EG, Thummel KE, Tyndale RF. Predictors of Variation in CYP2A6 mRNA, Protein, and Enzyme Activity in a Human Liver Bank: Influence of Genetic and Nongenetic Factors. J Pharmacol Exp Ther 2017; 360:129-139. [PMID: 27815364 PMCID: PMC5193072 DOI: 10.1124/jpet.116.237594] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/02/2016] [Indexed: 12/19/2022] Open
Abstract
Cytochrome P450 2A6 CYP2A6: metabolizes several clinically relevant substrates, including nicotine, the primary psychoactive component in cigarette smoke. Smokers vary widely in their rate of inactivation and clearance of nicotine, altering numerous smoking phenotypes. We aimed to characterize independent and shared impact of genetic and nongenetic sources of variation in CYP2A6 mRNA, protein, and enzyme activity in a human liver bank (n = 360). For the assessment of genetic factors, we quantified levels of CYP2A6, cytochrome P450 oxidoreductase (POR), and aldo-keto reductase 1D1 (AKR1D1) mRNA, and CYP2A6 and POR proteins. CYP2A6 enzyme activity was determined through measurement of cotinine formation from nicotine and 7-hydroxycoumarin formation from coumarin. Donor DNA was genotyped for CYP2A6, POR, and AKR1D1 genetic variants. Nongenetic factors assessed included gender, age, and liver disease. CYP2A6 phenotype measures were positively correlated to each other (r values ranging from 0.47-0.88, P < 0.001). Female donors exhibited higher CYP2A6 mRNA expression relative to males (P < 0.05). Donor age was weakly positively correlated with CYP2A6 protein (r = 0.12, P < 0.05) and activity (r = 0.20, P < 0.001). CYP2A6 reduced-function genotypes, but not POR or AKR1D1 genotypes, were associated with lower CYP2A6 protein (P < 0.001) and activity (P < 0.01). AKR1D1 mRNA was correlated with CYP2A6 mRNA (r = 0.57, P < 0.001), protein (r = 0.30, P < 0.001), and activity (r = 0.34, P < 0.001). POR protein was correlated with CYP2A6 activity (r = 0.45, P < 0.001). Through regression analyses, we accounted for 17% (P < 0.001), 37% (P < 0.001), and 77% (P < 0.001) of the variation in CYP2A6 mRNA, protein, and activity, respectively. Overall, several independent and shared sources of variation in CYP2A6 activity in vitro have been identified, which could translate to variable hepatic clearance of nicotine.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Bhagwat Prasad
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Katrina G Claw
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Patricia Stapleton
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Amarjit Chaudhry
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Erin G Schuetz
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Kenneth E Thummel
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
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Associations of cytochrome P450 oxidoreductase genetic polymorphisms with smoking cessation in a Chinese population. Hum Genet 2016; 135:1389-1397. [DOI: 10.1007/s00439-016-1728-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 09/11/2016] [Indexed: 12/28/2022]
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15
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The P450 oxidoreductase (POR) rs2868177 and cytochrome P450 (CYP) 2B6*6 polymorphisms contribute to the interindividual variability in human CYP2B6 activity. Eur J Clin Pharmacol 2016; 72:1205-1213. [DOI: 10.1007/s00228-016-2095-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/06/2016] [Indexed: 01/11/2023]
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