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Bhardwaj JK, Siwach A, Sachdeva SN. Nicotine as a female reproductive toxicant-A review. J Appl Toxicol 2024. [PMID: 39323358 DOI: 10.1002/jat.4702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 08/28/2024] [Accepted: 09/11/2024] [Indexed: 09/27/2024]
Abstract
The preceding decades have seen an extensive emergence of the harmful effects of tobacco smoke on systemic health. Among the various compounds of tobacco, nicotine is one of the principal, potentially hazardous, and toxic components which is an oxidant agent that can affect both men's and women's fertility. Nicotine exerts its effect by modulating the expression of transmembrane ligand-gated ion channels called nicotinic acetylcholine receptors. The activities of female reproduction might be disrupted by exposure to nicotine at various sites, such as the ovary or reproductive tract. It's been demonstrated that nicotine might cause oxidative stress, apoptosis, hormonal imbalance, abnormalities in chromosomal segregation, impact oocyte development, and disruption in ovarian morphology and functions. This review paper summarizes the findings and provides an updated overview of the evidence on the harmful effects of nicotine use on women's reproductive health and the resulting detrimental impacts on the body. Additionally, it provides the detailed possible mechanisms involved in impairing reproductive processes like folliculogenesis, oocyte maturation, steroidogenesis, and pregnancy in different animal species.
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Affiliation(s)
- Jitender Kumar Bhardwaj
- Reproductive Physiology Laboratory, Department of Zoology, Kurukshetra University, Kurukshetra, Haryana, India
| | - Anshu Siwach
- Reproductive Physiology Laboratory, Department of Zoology, Kurukshetra University, Kurukshetra, Haryana, India
| | - Som Nath Sachdeva
- Department of Civil Engineering, National Institute of Technology, Kurukshetra and Kurukshetra University, Kurukshetra, Haryana, India
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Effects of Genetic Variants in the Nicotine Metabolism Pathway on Smoking Cessation. Genet Res (Camb) 2022; 2022:2917881. [PMID: 36245555 PMCID: PMC9534651 DOI: 10.1155/2022/2917881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/02/2022] [Indexed: 11/21/2022] Open
Abstract
Background We aimed to investigate the associations of various genetic variants in the nicotine metabolism pathway with smoking cessation (SC) in the Chinese Han population. Method A case-control study was conducted where 363 successful smoking quitters were referred to as cases, and 345 failed smoking quitters were referred to as controls. A total of 42 genetic variants in 10 genes were selectedand genotyped. The weighted gene score was applied to analyze the whole gene effect. Logistic regression was used to explore associations of each genetic variant and gene score with smoking cessation. Results Our study found that the variants CYP2A6∗4, rs11726322, rs12233719, and rs3100 were associated with a higher probability of quitting smoking, while rs3760657 was associated with a lower probability of quitting smoking. Moreover, the gene scores of CYP2D6, FMO3, UGT2B10, UGT1A9, UGT2B7, and UGT2B15 were shown to exert a positive effect, while the gene score of CYP2B6 was detected to exert a negative effect on successful smoking cessation. Conclusion This study revealed that genetic variants in the nicotine metabolic pathway were associated with smoking cessation in the Chinese Han population.
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Murphy SE. Biochemistry of nicotine metabolism and its relevance to lung cancer. J Biol Chem 2021; 296:100722. [PMID: 33932402 PMCID: PMC8167289 DOI: 10.1016/j.jbc.2021.100722] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/27/2022] Open
Abstract
Nicotine is the key addictive constituent of tobacco. It is not a carcinogen, but it drives smoking and the continued exposure to the many carcinogens present in tobacco. The investigation into nicotine biotransformation has been ongoing for more than 60 years. The dominant pathway of nicotine metabolism in humans is the formation of cotinine, which occurs in two steps. The first step is cytochrome P450 (P450, CYP) 2A6–catalyzed 5′-oxidation to an iminium ion, and the second step is oxidation of the iminium ion to cotinine. The half-life of nicotine is longer in individuals with low P450 2A6 activity, and smokers with low activity often decrease either the intensity of their smoking or the number of cigarettes they use compared with those with “normal” activity. The effect of P450 2A6 activity on smoking may influence one's tobacco-related disease risk. This review provides an overview of nicotine metabolism and a summary of the use of nicotine metabolite biomarkers to define smoking dose. Some more recent findings, for example, the identification of uridine 5′-diphosphoglucuronosyltransferase 2B10 as the catalyst of nicotine N-glucuronidation, are discussed. We also describe epidemiology studies that establish the contribution of nicotine metabolism and CYP2A6 genotype to lung cancer risk, particularly with respect to specific racial/ethnic groups, such as those with Japanese, African, or European ancestry. We conclude that a model of nicotine metabolism and smoking dose could be combined with other lung cancer risk variables to more accurately identify former smokers at the highest risk of lung cancer and to intervene accordingly.
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Affiliation(s)
- Sharon E Murphy
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, USA.
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Perez-Paramo YX, Lazarus P. Pharmacogenetics factors influencing smoking cessation success; the importance of nicotine metabolism. Expert Opin Drug Metab Toxicol 2021; 17:333-349. [PMID: 33322962 PMCID: PMC8049967 DOI: 10.1080/17425255.2021.1863948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/10/2020] [Indexed: 01/12/2023]
Abstract
Introduction: Smoking remains a worldwide epidemic, and despite an increase in public acceptance of the harms of tobacco use, it remains the leading cause of preventable death. It is estimated that up to 70% of all smokers express a desire to quit, but only 3-5% of them are successful.Areas covered: The goal of this review was to evaluate the current status of smoking cessation treatments and the feasibility of implementing personalized-medicine approaches to these pharmacotherapies. We evaluated the genetics associated with higher levels of nicotine addiction and follow with an analysis of the genetic variants that affect the nicotine metabolic ratio (NMR) and the FDA approved treatments for smoking cessation. We also highlighted the gaps in the process of translating current laboratory understanding into clinical practice, and the benefits of personalized treatment approaches for a successful smoking cessation strategy.Expert opinion: Evidence supports the use of tailored therapies to ensure that the most efficient treatments are utilized in an individual's smoking cessation efforts. An understanding of the genetic effects on the efficacy of individualized smoking cessation pharmacotherapies is key to smoking cessation, ideally utilizing a polygenetic risk score that considers all genetic variation.
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Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
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Borrego-Soto G, Perez-Paramo YX, Chen G, Santuario-Facio SK, Santos-Guzman J, Posadas-Valay R, Alvarado-Monroy FM, Balderas-Renteria I, Medina-Gonzalez R, Ortiz-Lopez R, Lazarus P, Rojas-Martinez A. Genetic variants in CYP2A6 and UGT1A9 genes associated with urinary nicotine metabolites in young Mexican smokers. THE PHARMACOGENOMICS JOURNAL 2020; 20:586-594. [PMID: 31959879 PMCID: PMC7375952 DOI: 10.1038/s41397-020-0147-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 12/19/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
Nicotine is the major pharmacologically active substance in tobacco. Several studies have examined genotypes related to nicotine metabolism, but few studies have been performed in the Mexican population. The objective was to identify associations between gene variants in metabolizing enzymes and the urinary levels of nicotine metabolites among Mexican smokers. The levels of nicotine and its metabolites were determined in the urine of 88 young smokers from Mexico, and 167 variants in 24 genes associated with nicotine metabolism were genotyped by next-generation sequencing (NGS). Trans-3'-hydroxy-cotinine (3HC) and 4-hydroxy-4-(3-pyridyl)-butanoic acid were the most abundant metabolites (35 and 17%, respectively). CYP2A6*12 was associated with 3HC (p = 0.014). The rs145014075 was associated with creatinine-adjusted levels of nicotine (p = 0.035), while the rs12471326 (UGT1A9) was associated to cotinine-N-glucuronide (p = 0.030). CYP2A6 and UGT1A9 variants are associated to nicotine metabolism. 4HPBA metabolite was an abundant urinary metabolite in young Mexican smokers.
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Affiliation(s)
- Gissela Borrego-Soto
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Yadira X Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | | | - Jesus Santos-Guzman
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Rodolfo Posadas-Valay
- Facultad de Medicina, Centro Universitario de Salud, Universidad Autonoma de Nuevo Leon, Monterrey, Mexico
| | | | | | - Ramses Medina-Gonzalez
- Centro de Investigación y Desarrollo en Ciencias de la Salud, Universidad Autonoma de Nuevo Leon, Monterrey, Mexico
| | - Rocio Ortiz-Lopez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Augusto Rojas-Martinez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico.
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Taghavi T, Arger CA, Heil SH, Higgins ST, Tyndale RF. Longitudinal Influence of Pregnancy on Nicotine Metabolic Pathways. J Pharmacol Exp Ther 2018; 364:238-245. [PMID: 29158210 PMCID: PMC5774213 DOI: 10.1124/jpet.117.245126] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/15/2017] [Indexed: 11/22/2022] Open
Abstract
Nicotine metabolism increases in pregnancy, which may contribute to the difficulties that pregnant women have in quitting smoking. We aimed to determine the extent and timing of changes in nicotine metabolic pathways, including C-oxidation, N-glucuronidation, and the pregnancy-induced influences on the activity of enzymes mediating these pathways (CYP2A6 and UGT2B10, respectively). Current smoking pregnant women (n = 47) provided a urine sample during early pregnancy (12.5 weeks), late pregnancy (28.9 weeks), and 6 months postpartum. Concentrations of urinary nicotine and metabolites were analyzed using liquid chromatography tandem mass spectrometry and compared using general linear repeated measures analyses. Nicotine C-oxidation was 1.07-fold (P = 0.12) and 1.11-fold (P < 0.001) higher at early and late pregnancy, respectively, compared with postpartum. Nicotine N-glucuronidation was 1.33-fold (P = 0.06) and 1.67-fold (P = 0.003) higher at early and late pregnancy, respectively, compared with postpartum. The CYP2A6 phenotype ratio (total 3'-hydroxycotinine/cotinine) was significantly higher at early and late pregnancy compared with postpartum (all P < 0.05) and correlated with nicotine C-oxidation (all P < 0.001), suggesting CYP2A6 activity is induced during pregnancy. The UGT2B10 phenotype ratio (nicotine glucuronide/nicotine) was higher at early and late pregnancy compared with postpartum (P = 0.07 and P < 0.05, respectively) and correlated with a second UGT2B10 phenotype ratio (cotinine glucuronide/cotinine) (all P < 0.001), suggesting UGT2B10 activity is induced during pregnancy. In conclusion, pregnancy-induced increases in nicotine metabolism start by 12 weeks gestation and continue as pregnancy progresses most likely due to induction of CYP2A6 and UGT2B10, resulting in potential reductions in the effectiveness of nicotine replacement therapies and an increase in metabolism of other CYP2A6 and UGT2B10 substrates during pregnancy.
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Affiliation(s)
- Taraneh Taghavi
- Departments of Pharmacology and Toxicology (T.T., R.F.T.) and Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; University of Vermont Center on Tobacco Regulatory Science, Burlington, Vermont (C.A.A., S.H.H., S.T.H.); Departments of Psychiatry (C.A.A., S.H.H., S.T.H.) and Psychological Science (S.H.H., S.T.H.), University of Vermont, Burlington, Vermont; and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (R.F.T.)
| | - Christopher A Arger
- Departments of Pharmacology and Toxicology (T.T., R.F.T.) and Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; University of Vermont Center on Tobacco Regulatory Science, Burlington, Vermont (C.A.A., S.H.H., S.T.H.); Departments of Psychiatry (C.A.A., S.H.H., S.T.H.) and Psychological Science (S.H.H., S.T.H.), University of Vermont, Burlington, Vermont; and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (R.F.T.)
| | - Sarah H Heil
- Departments of Pharmacology and Toxicology (T.T., R.F.T.) and Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; University of Vermont Center on Tobacco Regulatory Science, Burlington, Vermont (C.A.A., S.H.H., S.T.H.); Departments of Psychiatry (C.A.A., S.H.H., S.T.H.) and Psychological Science (S.H.H., S.T.H.), University of Vermont, Burlington, Vermont; and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (R.F.T.)
| | - Stephen T Higgins
- Departments of Pharmacology and Toxicology (T.T., R.F.T.) and Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; University of Vermont Center on Tobacco Regulatory Science, Burlington, Vermont (C.A.A., S.H.H., S.T.H.); Departments of Psychiatry (C.A.A., S.H.H., S.T.H.) and Psychological Science (S.H.H., S.T.H.), University of Vermont, Burlington, Vermont; and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (R.F.T.)
| | - Rachel F Tyndale
- Departments of Pharmacology and Toxicology (T.T., R.F.T.) and Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; University of Vermont Center on Tobacco Regulatory Science, Burlington, Vermont (C.A.A., S.H.H., S.T.H.); Departments of Psychiatry (C.A.A., S.H.H., S.T.H.) and Psychological Science (S.H.H., S.T.H.), University of Vermont, Burlington, Vermont; and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (R.F.T.)
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7
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Tanner JA, Tyndale RF. Variation in CYP2A6 Activity and Personalized Medicine. J Pers Med 2017; 7:jpm7040018. [PMID: 29194389 PMCID: PMC5748630 DOI: 10.3390/jpm7040018] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022] Open
Abstract
The cytochrome P450 2A6 (CYP2A6) enzyme metabolizes several clinically relevant substrates, including nicotine-the primary psychoactive component in cigarette smoke. The gene that encodes the CYP2A6 enzyme is highly polymorphic, resulting in extensive interindividual variation in CYP2A6 enzyme activity and the rate of metabolism of nicotine and other CYP2A6 substrates including cotinine, tegafur, letrozole, efavirenz, valproic acid, pilocarpine, artemisinin, artesunate, SM-12502, caffeine, and tyrosol. CYP2A6 expression and activity are also impacted by non-genetic factors, including induction or inhibition by pharmacological, endogenous, and dietary substances, as well as age-related changes, or interactions with other hepatic enzymes, co-enzymes, and co-factors. As variation in CYP2A6 activity is associated with smoking behavior, smoking cessation, tobacco-related lung cancer risk, and with altered metabolism and resulting clinical responses for several therapeutics, CYP2A6 expression and enzyme activity is an important clinical consideration. This review will discuss sources of variation in CYP2A6 enzyme activity, with a focus on the impact of CYP2A6 genetic variation on metabolism of the CYP2A6 substrates.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada.
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Abstract
Nicotine is the primary addictive agent in tobacco, and P450 2A6 (gene name: CYP2A6) is the primary catalyst of nicotine metabolism. It was proposed more than 20 years ago that individuals who metabolize nicotine poorly would smoke less, either fewer cigarettes per day or less intensely per cigarette, compared to smokers who metabolize nicotine more efficiently. These poor metabolizers would then be less likely to develop lung cancer due to their lower exposure to the many carcinogens delivered with nicotine in each puff of smoke. Numerous studies have reported that smokers who carry reduced activity or null CYP2A6 alleles do smoke less. Yet only in Asian populations, both Japanese and Chinese, which have a high prevalence of genetic variants, has a link between CYP2A6, smoking dose, and lung cancer been established. In other ethnic groups, it has been challenging to confirm a direct link between P450 2A6-mediated nicotine metabolism and the risk of lung cancer. This challenge is due in part to the difficulty in accurately quantifying smoking dose and accurately predicting or measuring P450 2A6-mediated nicotine metabolism. Biomarkers of nicotine metabolism and smoking exposure, including the ratio of trans-3-hydroxycotine to cotinine, a measure of P450 2A6 activity and plasma cotinine, or urinary total nicotine equivalents (the sum of nicotine and six metabolites) as measures of exposure are useful for addressing this challenge. However, to take full advantage of these biomarkers in the study of ethnic/racial differences in the risk of lung cancer requires the complete characterization of nicotine metabolism across ethnic/racial groups. Variation in metabolism pathways, other than those catalyzed by P450 2A6, can impact biomarkers of both nicotine metabolism and dose. This is clearly important for smokers with low levels of UGT2B10-catalyzed nicotine and cotinine glucuronidation because the UGT2B10 genotype influences plasma cotinine levels. Cotinine is not glucuronidated in 15% of African American smokers (compared to 1% of Whites) due to the prevalence of a UGT2B10 splice variant. This variant contributes significantly to the higher plasma cotinine levels per cigarette in this group and may also influence the accuracy of the 3HCOT to cotinine ratio as a measure of P450 2A6 activity.
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Affiliation(s)
- Sharon E. Murphy
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
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Pattanawongsa A, Nair PC, Rowland A, Miners JO. Human UDP-Glucuronosyltransferase (UGT) 2B10: Validation of Cotinine as a Selective Probe Substrate, Inhibition by UGT Enzyme-Selective Inhibitors and Antidepressant and Antipsychotic Drugs, and Structural Determinants of Enzyme Inhibition. ACTA ACUST UNITED AC 2015; 44:378-88. [PMID: 26669329 DOI: 10.1124/dmd.115.068213] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/14/2015] [Indexed: 02/05/2023]
Abstract
Although there is evidence for an important role of UGT2B10 in the N-glucuronidation of drugs and other xenobiotics, the inhibitor selectivity of this enzyme is poorly understood. This study sought primarily to characterize the inhibition selectivity of UGT2B10 by UDP-glucuronosyltransferase (UGT) enzyme-selective inhibitors used for reaction phenotyping, and 34 antidepressant and antipsychotic drugs that contain an amine functional group. Initial studies demonstrated that cotinine is a highly selective substrate of human liver microsomal UGT2B10. The kinetics of cotinine N-glucuronidation by recombinant UGT and human liver microsomes (± bovine serum albumin) were consistent with the involvement of a single enzyme. Of the UGT enzyme-selective inhibitors employed for reaction phenotyping, only the UGT2B4/7 inhibitor fluconazole reduced recombinant UGT2B10 activity to an appreciable extent. The majority of antidepressant and antipsychotic drugs screened for effects on UGT2B10 inhibited enzyme activity with IC50 values <100 µM. The most potent inhibition was observed with the tricyclic antidepressants amitriptyline and doxepin and the tetracyclic antidepressant mianserin, and the structurally related compounds desloratadine and loratadine. Molecular modeling using a ligand-based approach indicated that hydrophobic and charge interactions are involved in inhibitor binding, whereas spatial features influence the potency of UGT2B10 inhibition. Respective mean Ki,u (± S.D.) values for amitriptyline, doxepin, and mianserin inhibition of human liver microsomal UGT2B10 were 0.61 ± 0.05, 0.95 ± 0.18, and 0.43 ± 0.01 µM. In vitro-in vivo extrapolation indicates that these drugs may perpetrate inhibitory drug-drug interactions when coadministered with compounds that are cleared predominantly by UGT2B10.
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Affiliation(s)
- Attarat Pattanawongsa
- Department of Clinical Pharmacology (A.P., P.C.N., A.R., J.O.M.) and Flinders Centre for Innovation in Cancer (A.R., P.C.N., J.O.M.), Flinders University School of Medicine, Adelaide, Australia
| | - Pramod C Nair
- Department of Clinical Pharmacology (A.P., P.C.N., A.R., J.O.M.) and Flinders Centre for Innovation in Cancer (A.R., P.C.N., J.O.M.), Flinders University School of Medicine, Adelaide, Australia
| | - Andrew Rowland
- Department of Clinical Pharmacology (A.P., P.C.N., A.R., J.O.M.) and Flinders Centre for Innovation in Cancer (A.R., P.C.N., J.O.M.), Flinders University School of Medicine, Adelaide, Australia
| | - John O Miners
- Department of Clinical Pharmacology (A.P., P.C.N., A.R., J.O.M.) and Flinders Centre for Innovation in Cancer (A.R., P.C.N., J.O.M.), Flinders University School of Medicine, Adelaide, Australia
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Lacombe L, Fradet V, Lévesque É, Pouliot F, Larue H, Bergeron A, Hovington H, Caron A, Nguile-Makao M, Harvey M, Fradet Y, Guillemette C. Phase II Drug-Metabolizing Polymorphisms and Smoking Predict Recurrence of Non–Muscle-Invasive Bladder Cancer: A Gene–Smoking Interaction. Cancer Prev Res (Phila) 2015; 9:189-95. [DOI: 10.1158/1940-6207.capr-15-0069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 11/04/2015] [Indexed: 11/16/2022]
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Mishra A, Chaturvedi P, Datta S, Sinukumar S, Joshi P, Garg A. Harmful effects of nicotine. Indian J Med Paediatr Oncol 2015; 36:24-31. [PMID: 25810571 PMCID: PMC4363846 DOI: 10.4103/0971-5851.151771] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel.
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Affiliation(s)
- Aseem Mishra
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Pankaj Chaturvedi
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Sourav Datta
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Snita Sinukumar
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Poonam Joshi
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Apurva Garg
- Department of Surgical Oncology, Head and Neck Services, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
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Wassenaar CA, Conti DV, Das S, Chen P, Cook EH, Ratain MJ, Benowitz NL, Tyndale RF. UGT1A and UGT2B genetic variation alters nicotine and nitrosamine glucuronidation in european and african american smokers. Cancer Epidemiol Biomarkers Prev 2014; 24:94-104. [PMID: 25277794 DOI: 10.1158/1055-9965.epi-14-0804] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Identifying sources of variation in the nicotine and nitrosamine metabolic inactivation pathways is important to understanding the relationship between smoking and cancer risk. Numerous UGT1A and UGT2B enzymes are implicated in nicotine and nitrosamine metabolism in vitro; however, little is known about their roles in vivo. METHODS Within UGT1A1, UGT1A4, UGT1A9, UGT2B7, UGT2B10, and UGT2B17, 47 variants were genotyped, including UGT2B10*2 and UGT2B17*2. The association between variation in these UGTs and glucuronidation activity within European and African American current smokers (n = 128), quantified as urinary ratios of the glucuronide over unconjugated compound for nicotine, cotinine, trans-3'-hydroxycotinine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), was investigated in regression models assuming a dominant effect of variant alleles. RESULTS Correcting for multiple testing, three UGT2B10 variants were associated with cotinine glucuronidation, rs2331559 and rs11726322 in European Americans and rs835309 in African Americans (P ≤ 0.0002). Additional variants predominantly in UGT2B10 were nominally associated with nicotine (P = 0.008-0.04) and cotinine (P = <0.001-0.02) glucuronidation in both ethnicities in addition to UGT2B10*2 in European Americans (P = 0.01, P < 0.001). UGT2B17*2 (P = 0.03) in European Americans and UGT2B7 variants (P = 0.02-0.04) in African Americans were nominally associated with 3HC glucuronidation. UGT1A (P = 0.007-0.01), UGT2B10 (P = 0.02), and UGT2B7 (P = 0.02-0.03) variants in African Americans were nominally associated with NNAL glucuronidation. CONCLUSIONS Findings from this initial in vivo study support a role for multiple UGTs in the glucuronidation of tobacco-related compounds in vivo, in particular UGT2B10 and cotinine glucuronidation. IMPACT Findings also provide insight into ethnic differences in glucuronidation activity, which could be contributing to ethnic disparities in the risk for smoking-related cancers. Cancer Epidemiol Biomarkers Prev; 24(1); 94-104. ©2014 AACR.
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Affiliation(s)
- Catherine A Wassenaar
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - David V Conti
- Department of Preventive Medicine, University of Southern California, Los Angeles, California
| | - Soma Das
- Department of Human Genetics, University of Chicago, Chicago, Illinois
| | - Peixian Chen
- Department of Human Genetics, University of Chicago, Chicago, Illinois
| | - Edwin H Cook
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Mark J Ratain
- Department of Medicine, Committee on Clinical Pharmacology and Pharmacogenomics, Cancer Research Center, University of Chicago, Chicago, Illinois
| | - Neal L Benowitz
- Division of Clinical Pharmacology and Experimental Therapeutics, Department of Medicine, University of California San Francisco, San Francisco, California. Department of Bioengineering and Therapeutic Science, University of California San Francisco, San Francisco, California
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada. Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada. Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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13
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Fujiwara R, Sumida K, Kutsuno Y, Sakamoto M, Itoh T. UDP-glucuronosyltransferase (UGT) 1A1 mainly contributes to the glucuronidation of trovafloxacin. Drug Metab Pharmacokinet 2014; 30:82-8. [PMID: 25760534 DOI: 10.1016/j.dmpk.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 11/26/2022]
Abstract
Identification of drug-metabolizing enzyme(s) responsible for the metabolism of drugs is an important step to understand not only interindividual variability in pharmacokinetics but also molecular mechanisms of metabolite-related toxicity. While it was reported that the major metabolic pathway of trovafloxacin, which is an antibiotic, was glucuronidation, the UDP-glucuronosyltransferase (UGT) isoform(s) responsible for the trovafloxacin glucuronidation has not been identified yet. In the present study, among the functional human UGT members, UGT1A1, UGT1A3, and UGT1A9 exhibited higher trovafloxacin acyl-glucuronidation activities. While other UGT members such as UGT1A8, UGT2B7, and UGT2B15 showed glucuronidation activity toward trovafloxacin, the metabolic velocity was extremely low. In human liver microsomes, trovafloxacin acyl-glucuronidation followed the Hill equation with S50 value of 95 μM, Vmax value of 243 pmol/min per mg, and a Hill coefficient of 2.0, while the UGT1A1-expressing system displayed Michaelis-Menten kinetics with a substrate inhibition, with Km value of 759 μM and Vmax value of 1160 pmol/min per mg. In human liver microsomes prepared from poor metabolizers (UGT1A1*28/*28), significantly reduced trovafloxacin acyl-glucuronide formation activity was observed, indicating that UGT1A1 mainly, while other UGT members such as UGT1A3 and UGT1A9 partially, contributes to the glucuronidation of trovafloxacin.
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Affiliation(s)
- Ryoichi Fujiwara
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
| | - Kyohei Sumida
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuki Kutsuno
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masaya Sakamoto
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Tomoo Itoh
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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14
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Liquid chromatography–tandem mass spectrometry method for measurement of nicotine N-glucuronide: A marker for human UGT2B10 inhibition. J Pharm Biomed Anal 2011; 55:964-71. [DOI: 10.1016/j.jpba.2011.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 03/15/2011] [Accepted: 03/22/2011] [Indexed: 11/18/2022]
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15
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Seo KA, Bae SK, Choi YK, Choi CS, Liu KH, Shin JG. Metabolism of 1′- and 4-Hydroxymidazolam by Glucuronide Conjugation Is Largely Mediated by UDP-Glucuronosyltransferases 1A4, 2B4, and 2B7. Drug Metab Dispos 2010; 38:2007-13. [DOI: 10.1124/dmd.110.035295] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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16
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Abstract
The molecular genetics of nicotine metabolism involves multiple polymorphic catalytic enzymes. Variation in metabolic pathways results in nicotine disposition kinetics that differ between individuals and ethnic groups. Twin studies indicate that a large part of this variance is genetic in origin, although environmental influences also contribute. The primary aim of this chapter is to review the current knowledge regarding the genetic variability in the enzymes that metabolize nicotine in humans. The focus is on describing the genetic polymorphisms that exist in cytochromes P450 (CYPs), aldehyde oxidase 1 (AOX1), UDP-glucuronosyltransferases (UGTs), and flavin-containing monooxygenase 3 (FMO3). Genetic studies have demonstrated that polymorphisms in CYP2A6, the primary enzyme responsible for nicotine breakdown, make a sizable contribution to the wide range of nicotine metabolic capacity observed in humans. Thus, special attention will be given to CYP2A6, because slower nicotine metabolism requires less frequent self-administration, and accordingly influences smoking behaviors. In addition, the molecular genetics of nicotine metabolism in nonhuman primates, mice, and rats will be reviewed briefly.
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Affiliation(s)
- Jill C Mwenifumbo
- Centre for Addiction & Mental Health and Department of Pharmacology, University of Toronto, Toronto, ON, Canada
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17
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Swan GE, Lessov-Schlaggar CN. Tobacco addiction and pharmacogenetics of nicotine metabolism. J Neurogenet 2009; 23:262-71. [PMID: 19152209 DOI: 10.1080/01677060802572903] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This paper presents a brief overview of several components of tobacco addiction, including: 1) the epidemiology of smoking in the United States and elsewhere around the world; 2) implications of the pharmacogenetic study of nicotine metabolism for understanding tobacco addiction and its treatment; 3) the use of the twin design as an example of one strategy to understand the contribution of genetic and environmental factors to the pharmacokinetics of nicotine metabolism; 4) results from recent genomic studies of tobacco addiction in adults; and 5) a discussion of progress (past and future) toward the development of a comprehensive understanding of the pharmacogenetics of tobacco addiction and its treatment.
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Affiliation(s)
- Gary E Swan
- Center for Health Sciences, SRI International, Menlo Park, California 94025, USA.
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18
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Sharma G, Vijayaraghavan S. Nicotinic receptors containing the alpha7 subunit: a model for rational drug design. Curr Med Chem 2009; 15:2921-32. [PMID: 19075644 DOI: 10.2174/092986708786848703] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neuronal nicotinic receptor has gained considerable recognition as a target, not just for combating drug addiction but also for treating a number of illnesses ranging from neurodegenerative diseases to psychotic disorders like schizophrenia. This recognition has led to a burgeoning field examining the receptor at all levels. A class of nicotinic receptors that contains the alpha7 gene product, apparently as a homomer, illustrates this multidisciplinary approach. Here, we review recent progress in our understanding of this class of receptors based on data from molecular, structural, physiological and patho-physiological studies. These studies have set the stage for rational drug design to combat disorders of the central nervous system. The studies also exemplify the cautious approach needed in developing CNS therapies and the importance of physiology in tempering drug design.
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Affiliation(s)
- G Sharma
- Department of Physiology and Biophysics and Neuroscience Program, University of Colorado, Denver, School of Medicine, Aurora Colorado, USA
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19
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Chen G, Blevins-Primeau AS, Dellinger RW, Muscat JE, Lazarus P. Glucuronidation of Nicotine and Cotinine by UGT2B10: Loss of Function by the UGT2B10 Codon 67 (Asp>Tyr) Polymorphism. Cancer Res 2007; 67:9024-9. [PMID: 17909004 DOI: 10.1158/0008-5472.can-07-2245] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Nicotine, the major addicting agent in tobacco and tobacco smoke, undergoes a complex metabolic pathway, with ∼22% of nicotine urinary metabolites in the form of phase II N-glucuronidated compounds. Recent studies have shown that UGT2B10 is a major enzyme involved in the N-glucuronidation of several tobacco-specific nitrosamines. In the present study, microsomes of UGT2B10-overexpressing HEK293 cells exhibited high N-glucuronidation activity against both nicotine and cotinine with apparent KM's that were 37- and 3-fold lower than that observed for microsomes of UGT1A4-overexpressing cells against nicotine and cotinine, respectively. The KM of microsomes from wild-type (WT) UGT2B10-overexpressing cells for nicotine and cotinine was similar to that observed for human liver microsomes (HLM) against both substrates. The level of glucuronidated nicotine or cotinine in 112 HLM samples was correlated with UGT2B10 genotype; the levels of nicotine- and cotinine-glucuronide were 21% to 30% lower in specimens from subjects with the UGT2B10 (*1/*2) genotype compared with specimens from subjects with the WT UGT2B10 (*1/*1) genotype; a 5- and 16-fold lower level of nicotine- and cotinine-glucuronide formation, respectively, was observed in HLM from subjects with the UGT2B10 (*2/*2) genotype. In contrast to the relatively high activity observed for cells overexpressing WT UGT2B10 in vitro, little or no glucuronidation was observed for microsomes from cells overexpressing the UGT2B10*2 variant against either nicotine or cotinine. These data suggest that UGT2B10 is the major hepatic enzyme involved in nicotine/cotinine glucuronidation and that the UGT2B10*2 variant significantly reduces nicotine- and cotinine-N-glucuronidation formation and plays an important role in nicotine metabolism and elimination. [Cancer Res 2007;67(19):9024–9]
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Affiliation(s)
- Gang Chen
- Cancer Prevention and Control Program, Penn State Cancer Institute, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA
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20
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Kaivosaari S, Toivonen P, Hesse LM, Koskinen M, Court MH, Finel M. Nicotine Glucuronidation and the Human UDP-Glucuronosyltransferase UGT2B10. Mol Pharmacol 2007; 72:761-8. [PMID: 17576790 DOI: 10.1124/mol.107.037093] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Nicotine biotransformation affects the smoking habits of addicted individuals and therefore their health risk. Using an improved analytical method, we have discovered that the human UDP-glucuronosyltransferase (UGT) 2B10, a liver enzyme previously unknown to conjugate nicotine or exhibit considerable activity toward any compound, plays a major role in nicotine inactivation by direct conjugation with glucuronic acid at the aromatic nitrogen atom. The K(m) value of recombinant UGT2B10 for nicotine (0.29 mM) was similar to that determined for human liver microsomes (0.33 mM), whereas the K(m) value of UGT1A4 for nicotine was almost 10-fold greater (2.4 mM). UGT2B10 was also more active than UGT1A4 in N-glucuronidation of cotinine (oxidative nicotine metabolite), whereas UGT2B7 exhibited only low nicotine glucuronidation activity and was essentially inactive toward cotinine. UGT1A9 did not glucuronidate nicotine or cotinine. Quantitative reverse transcription-polymerase chain reaction showed that UGT2B10 mRNA was exclusively expressed in human liver, whereas UGTs 1A4 and 2B7 were expressed at comparable, although somewhat lower, levels in liver and several other extrahepatic tissues, including kidney and intestine. These findings for UGT2B10 (but not for UGT1A4 and UGT2B7) were mirrored by human tissue activities because nicotine and cotinine glucuronidation rates in intestine microsomes were less than 0.1% that of human liver microsomes. These novel findings solve two seemingly separate questions: which UGT is primarily responsible for nicotine glucuronidation in human liver, and what conjugation reactions are catalyzed by UGT2B10.
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Affiliation(s)
- Sanna Kaivosaari
- Department of Pharmacokinetics and Bioanalytics, Orion Corporation Orion Pharma, Espoo, Finland
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21
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Uesawa Y, Staines AG, Lockley D, Mohri K, Burchell B. Identification of the human liver UDP-glucuronosyltransferase involved in the metabolism of p-ethoxyphenylurea (dulcin). Arch Toxicol 2006; 81:163-8. [PMID: 16897040 DOI: 10.1007/s00204-006-0138-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 07/13/2006] [Indexed: 11/28/2022]
Abstract
Dulcin (DL), now banned, was once a widely used artificial sweetener. DL possesses an ureido group that is metabolized by direct glucuronidation in rabbit liver microsomes. Dulcin N-glucuronide (DNG) is the only type of ureido N-glucuronide known to date; ureido glucuronidation in humans has not been previously reported. Accordingly, the glucuronidation of DL was studied using human liver microsomes (HLM) and expressed human UDP-glucuronosyltransferase (UGT) enzymes. The average K (m) and V (max) values from nine HLM samples were 2.10 mM and 0.156 nmol/mg/min, respectively. Of the six human UGT isoforms screened for their ability to glucuronidate DL, only UGT1A1 and UGT1A9 showed activity. The apparent K (m) values using UGT1A1 and UGT1A9 were 5.06 and 6.99 mM, and the apparent V (max) values were 0.0461 and 0.106 nmol/min/mg, respectively. Phenolphthalein, a substrate for UGT1A9, inhibited DL glucuronidation in HLM competitively (K (i) = 0.356 mM), but bilirubin, a substrate for UGT1A1, did not. These results suggest that UGT1A9 is a key enzyme catalyzing the glucuronidation of DL.
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Affiliation(s)
- Yoshihiro Uesawa
- Department of Pharmaceutics, Clinical Pharmaceutics Laboratory, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo, 204-8588, Japan.
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22
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Abstract
Nicotine replacement therapy (NRT) is an effective treatment for smoking cessation, but as with all such pharmacotherapies, the majority of smokers who use NRT products do not stop smoking or remain abstinent long term. Treatment outcome is affected by a range of individual-specific factors, as well as the pharmacokinetic profile of each NRT formulation. This has led to speculation that abstinence rates could be improved if NRT treatments were individually tailored to best match each individual's needs and preferences. There are also populations for whom special product and dosage considerations are warranted to maximise treatment safety.This paper reviews the rationale for NRT treatment, standard dose recommendations and recommendations for how to best match NRT treatment to the specific needs of individual smokers. We also review emerging evidence that genetic profiling may one day be a useful consideration for tailoring NRT treatment.
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Affiliation(s)
- Jennifer B McClure
- Group Health Cooperative, Center for Health Studies, Seattle, Washington 98101, USA.
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23
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Swan GE, Benowitz NL, Lessov CN, Jacob P, Tyndale RF, Wilhelmsen K. Nicotine metabolism: the impact of CYP2A6 on estimates of additive genetic influence. Pharmacogenet Genomics 2005; 15:115-25. [PMID: 15861035 DOI: 10.1097/01213011-200502000-00007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To conduct a pharmacogenetic investigation of nicotine metabolism in twins. One hundred and thirty nine twin pairs [110 monozygotic (MZ) and 29 dizygotic (DZ)] underwent a 30-min infusion of stable isotope-labelled nicotine and its major metabolite, cotinine, followed by an 8-h in-hospital stay. Blood and urine samples were taken at regular intervals for analysis of nicotine, cotinine and metabolites by gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry and subsequent characterization of pharmacokinetic and metabolism phenotypes. DNA was genotyped to confirm zygosity and for variation in the gene for the primary enzyme involved in nicotine metabolism, CYP2A6 (alleles tested: *1, *1x2, *2, *4, *7, *9 and *12). Univariate biometric analyses quantified genetic and environmental influences on each pharmacokinetic measure in the presence and absence of covariates, including measured CYP2A6 genotype. The best-fitting model identified a substantial amount of variation in the weight-adjusted rate of total clearance of nicotine attributable to additive genetic influences [59.4%, 95% confidence interval (CI)=44.7-70.7]. The majority of variation in the clearance of nicotine via the cotinine pathway was similarly genetically influenced (60.8%, 95% CI=46.9-71.5). Heritability estimates were reduced to 54.2% and 51.8%, respectively, but remained substantial after taking into account the effect of variation in CYP2A6 genotype. These results suggest the involvement of additional genetic factors (e.g. uncharacterized or novel CYP2A6 alleles as well as other genes in the metabolic pathway) that remain to be identified.
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Affiliation(s)
- Gary E Swan
- Center for Health Sciences, SRI International, Menlo Park, California 94025, USA.
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24
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Kuehl GE, Lampe JW, Potter JD, Bigler J. GLUCURONIDATION OF NONSTEROIDAL ANTI-INFLAMMATORY DRUGS: IDENTIFYING THE ENZYMES RESPONSIBLE IN HUMAN LIVER MICROSOMES. Drug Metab Dispos 2005; 33:1027-35. [PMID: 15843492 DOI: 10.1124/dmd.104.002527] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs), used for the treatment of pain and inflammation, are eliminated primarily through conjugation with polar sugar moieties to form glucuronides. Glucuronidation is catalyzed by the UDP-glucuronosyltransferases (UGT) superfamily. An inverse relationship may exist between glucuronidation activity and NSAID efficacy; however, specific UGTs catalyzing conjugation of the structurally diverse NSAIDs have yet to be identified systematically. Therefore, NSAID glucuronidation activity by 12 individually expressed UGTs was investigated by liquid chromatography-tandem mass spectrometry. The relative rates of NSAID glucuronidation varied among UGT enzymes examined, demonstrating specificity of the individual UGTs toward selected NSAIDs. Kinetic parameters were determined for expressed UGT Supersomes and compared with parameters determined in pooled human liver microsomes (HLMs). Comparison of K(m) values suggested roles for UGTs 1A3 and 2B7 in indene glucuronidation and UGTs 1A9, 2B4, and 2B7 in profen glucuronidation. Inhibitory studies in pooled HLMs support the role of UGTs 1A1, 1A3, 1A9, 2B4, and 2B7 in the glucuronidation of ibuprofen, flurbiprofen, and ketoprofen. Bilirubin did not inhibit indomethacin or diclofenac glucuronidation, suggesting that UGT1A1 was not involved in catalysis. Imipramine did not inhibit glucuronidation of sulindac, sulindac sulfone, indomethacin, or naproxen in pooled HLMs, suggesting that UGT1A3 was not a principal hepatic catalyst. Nevertheless, multiple UGT enzymes, most notably UGTs 1A1, 1A9, 2B4, and 2B7, seem to be involved in the hepatic catalysis of NSAID glucuronidation.
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Affiliation(s)
- Gwendolyn E Kuehl
- Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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25
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Abstract
Nicotine is of importance as the addictive chemical in tobacco, pharmacotherapy for smoking cessation, a potential medication for several diseases, and a useful probe drug for phenotyping cytochrome P450 2A6 (CYP2A6). We review current knowledge about the metabolism and disposition kinetics of nicotine, some other naturally occurring tobacco alkaloids, and nicotine analogs that are under development as potential therapeutic agents. The focus is on studies in humans, but animal data are mentioned when relevant to the interpretation of human data. The pathways of nicotine metabolism are described in detail. Absorption, distribution, metabolism, and excretion of nicotine and related compounds are reviewed. Enzymes involved in nicotine metabolism including cytochrome P450 enzymes, aldehyde oxidase, flavin-containing monooxygenase 3, amine N-methyltransferase, and UDP-glucuronosyltransferases are represented, as well as factors affecting metabolism, such as genetic variations in metabolic enzymes, effects of diet, age, gender, pregnancy, liver and kidney diseases, and racial and ethnic differences. Also effects of smoking and various inhibitors and inducers, including oral contraceptives, on nicotine metabolism are discussed. Due to the significance of the CYP2A6 enzyme in nicotine clearance, special emphasis is given to the effects and population distributions of CYP2A6 alleles and the regulation of CYP2A6 enzyme.
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Affiliation(s)
- Janne Hukkanen
- Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco Genreral Hospital Medical Center, and the Department of Medicine, University of California, San Francisco, Box 1220, San Francisco, CA 94143-1220, USA
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26
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Girard H, Court MH, Bernard O, Fortier LC, Villeneuve L, Hao Q, Greenblatt DJ, von Moltke LL, Perussed L, Guillemette C. Identification of common polymorphisms in the promoter of the UGT1A9 gene: evidence that UGT1A9 protein and activity levels are strongly genetically controlled in the liver. ACTA ACUST UNITED AC 2005; 14:501-15. [PMID: 15284532 DOI: 10.1097/01.fpc.0000114754.08559.27] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVES Polymorphisms in UDP-glucuronosyltransferases (UGTs) can influence detoxifying capacities and have considerable therapeutic implications in addition to influence various (patho)physiological processes. UGT1A9 plays a central role in the metabolism of various classes of therapeutic drugs in addition to carcinogens and steroids. The great interindividual variability of UGT1A9-mediated glucuronidation remains poorly explained, while evidence for its genetic origin exists. METHODS The proximal UGT1A9 promoter was screened for polymorphisms by sequencing and, the contribution of single nucleotide polymorphisms (SNPs) to the variability of UGT1A9 protein levels and activity was evaluated. RESULTS We confirmed the presence of the -109 to -98 T10 polymorphism and found ten novel SNPs that generated a diversity of haplotypes in two independent populations. In a panel of 48 human liver microsomes, the UGT1A9 expression varied by 17-fold and was significantly correlated with SNPs -275, -331/-440, -665 and -2152. The base insertion T10 reported to increase reporter gene expression in HepG2 cells [] was not linked to -275 and -2152 SNPs and was not associated with changes in UGT1A9 protein levels. Compared to wild-type individuals, there were statistically significant higher glucuronidating activities in livers with the -275 and -2152 using mycophenolic acid and propofol as UGT1A9 substrates, indicating an extensive glucuronidator phenotype associated with these variants. CONCLUSIONS This is the first study to demonstrate that naturally occurring sequence variations in the UGT1A9 promoter are informative in predicting the levels of protein and glucuronidating activity, providing a potential mechanism for interindividual variation in UGT1A9-mediated metabolism.
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Affiliation(s)
- Hugo Girard
- Canada Research Chair in Pharmacogenomics, Laboratory of Pharmacogenomics, Oncology and Molecular Endocrinology Research Center, CHUL Research Center and Faculty of Pharmacy, Laval University, Québec, Canada
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27
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Yamanaka H, Nakajima M, Nishimura K, Yoshida R, Fukami T, Katoh M, Yokoi T. Metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted. Eur J Pharm Sci 2005; 22:419-25. [PMID: 15265511 DOI: 10.1016/j.ejps.2004.04.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 04/15/2004] [Accepted: 04/22/2004] [Indexed: 11/25/2022]
Abstract
Generally, 70-80% of absorbed nicotine is mainly metabolized to cotinine by cytochrome P450 (CYP) 2A6. There is genetic polymorphism in the human CYP2A6 gene. Among several mutated alleles, CYP2A6*4 allele is a whole deleted type. The purpose of the present study was to clarify the metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for nicotine and its nine metabolites. Excretion levels of nicotine and its metabolites in 24 h accumulated urine after the chewing of one piece of nicotine gum were evaluated in five Japanese subjects whose CYP2A6 genotype was determined. In three subjects with CYP2A6*1A/CYP2A6*1A, CYP2A6*1A/CYP2A6*1B, and CYP2A6*1A/CYP2A6*4 (group I), nicotine was mainly excreted as cotinine, trans-3'-hydroxycotinine, and their glucuronide (approximately 60%). In contrast, in two subjects with CYP2A6*4/CYP2A6*4 (group II), trace levels of cotinine, cotinine N-glucuronide, and cotinine 1'-N-oxide were detected. Trans-3'-hydroxycotinine and its O-glucuronide were not detected. The excretion levels of nicotine itself, nicotine N-glucuronide, and nicotine 1'-N-oxide were higher than those in the other three subjects. The total excretion levels of these three compounds were approximately 95% in group II versus 35% in group I. However, the sum of the excretion levels of nicotine and all metabolites was similar among these five subjects. This is the first report of the metabolic profile of nicotine in subjects whose CYP2A6 gene is deleted.
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Affiliation(s)
- Hiroyuki Yamanaka
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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28
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Saeki M, Saito Y, Jinno H, Sai K, Hachisuka A, Kaniwa N, Ozawa S, Kawamoto M, Kamatani N, Shirao K, Minami H, Ohtsu A, Yoshida T, Saijo N, Komamura K, Kotake T, Morishita H, Kamakura S, Kitakaze M, Tomoike H, Sawada JI. Genetic Variations and Haplotypes of UGT1A4 in a Japanese Population. Drug Metab Pharmacokinet 2005; 20:144-51. [PMID: 15855727 DOI: 10.2133/dmpk.20.144] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nineteen genetic variations, including 11 novel ones, were found in exon 1 and its flanking region of the UDP-glucuronosyltransferase (UGT) 1A4 gene from 256 Japanese subjects, consisting of 60 healthy volunteers, 88 cancer patients and 108 arrhythmic patients. These variations include -217T>G and -36G>A in the 5'-flanking region, 30G>A (P10P), 127delA (43fsX22; frame-shift from codon 43 resulting in the termination at the 22nd codon, codon 65), 175delG (59fsX6), 271C>T (R91C), 325A>G (R109G), and 357T>C (N119N) in exon 1, and IVS1+1G>T, IVS1+98A>G and IVS1+101G>T in the following intron. Among them, 127delA and 175delG can confer early termination of translation, resulting in an immature protein that probably lacks enzymatic activity. Variation IVS1+1G>T is located at a splice donor site and thus may lead to aberrant splicing. Since we did not find any significant differences in the frequencies of all the variations among the three subject groups, the data were analyzed as one group. The allele frequencies of the novel variations were 0.006 for IVS1+101G>T, 0.004 for 30G>A (P10P) and 357T>C (N119N), and 0.002 for the 8 other variations. In addition, the two known nonsynonymous single nucleotide polymorphisms (SNPs), 31C>T (R11W) and 142T>G (L48V), were found at 0.012 and 0.129 frequencies, respectively. The SNP 70C>A (P24T), mostly linked with 142T>G (L48V) in German Caucasians, was not detected in this study. Sixteen haplotypes were identified or inferred, and some haplotypes were confirmed by cloning and sequencing. It was shown that most of 142T>G (L48V) was linked with -219C>T, -163G>A, 448T>C (L150L), 804G>A (P268P), and IVS1+43C>T, comprising haplotype *3a; haplotype *4a harbors 31C>T (R11W); 127delA (43fsX22) and 142T>G (L48V) were linked (haplotype *5a); 175delG (59fsX6) was linked with 325A>G (R109G) (*6a haplotype); and -219C>T, -163G>A, 142T>G (L48V), 271C>T (R91C), 448T>C (L150L), 804G>A (P268P), and IVS1+43C>T comprised haplotype *7a. Our results provide fundamental and useful information for genotyping UGT1A4 in the Japanese and probably Asian populations.
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Affiliation(s)
- Mayumi Saeki
- Project Team for Pharmacogenetics, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Nakajima M, Yokoi T. Interindividual Variability in Nicotine Metabolism: C-Oxidation and Glucuronidation. Drug Metab Pharmacokinet 2005; 20:227-35. [PMID: 16141602 DOI: 10.2133/dmpk.20.227] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nicotine has roles in the addiction to smoking, replacement therapy for smoking cessation, as a potential medication for several diseases such as Parkinson's disease, Alzheimer's disease, and ulcerative colitis. The absorbed nicotine is rapidly and extensively metabolized and eliminated to urine. A major pathway of nicotine metabolism is C-oxidation to cotinine, which is catalyzed by CYP2A6 in human livers. Cotinine is subsequently metabolized to trans-3'-hydroxycotinine by CYP2A6. Nicotine and cotinine are glucuronidated to N-glucuronides mainly by UGT1A4 and partly by UGT1A9. Trans-3'-hydroxycotinine is glucuronidated to O-glucuronide mainly by UGT2B7 and partly by UGT1A9. Approximately 90% of the total nicotine uptake is eliminated as these metabolites and nicotine itself. The nicotine metabolism is an important determinant of the clearance of nicotine. Recently, advances in the understanding of the interindividual variability in nicotine metabolism have been made. There are substantial data suggesting that the large interindividual differences in cotinine formation are associated with genetic polymorphisms of the CYP2A6 gene. Interethnic differences have also been observed in the cotinine formation and the allele frequencies of the CYP2A6 alleles. Since the genetic polymorphisms of the CYP2A6 gene have a major impact on nicotine clearance, its relationships with smoking behavior or the risk of lung cancer have been suggested. The metabolic pathways of the glucuronidation of nicotine, cotinine, and trans-3'-hydroxycotinine in humans would be one of the causal factors for the interindividual differences in nicotine metabolism. This review mainly summarizes recent results from our studies.
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Affiliation(s)
- Miki Nakajima
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
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30
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Yamanaka H, Nakajima M, Katoh M, Kanoh A, Tamura O, Ishibashi H, Yokoi T. TRANS-3′-HYDROXYCOTININE O- AND N-GLUCURONIDATIONS IN HUMAN LIVER MICROSOMES. Drug Metab Dispos 2004; 33:23-30. [PMID: 15470160 DOI: 10.1124/dmd.104.001701] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Trans-3'-hydroxycotinine is a major metabolite of nicotine in humans and is mainly excreted as O-glucuronide in smoker's urine. Incubation of human liver microsomes with UDP-glucuronic acid produces not only trans-3'-hydroxycotinine O-glucuronide but also N-glucuronide. The formation of N-glucuronide exceeds the formation of O-glucuronide in most human liver microsomes, although N-glucuronide has never been detected in human urine. Trans-3'-hydroxycotinine N-glucuronidation in human liver microsomes was significantly correlated with nicotine and cotinine N-glucuronidations, which are catalyzed mainly by UDP-glucuronosyltransferase (UGT)1A4 and was inhibited by imipramine and nicotine, which are substrates of UGT1A4. Recombinant UGT1A4 exhibited substantial trans-3'-hydroxycotinine N-glucuronosyltransferase activity. These results suggest that trans-3'-hydroxycotinine N-glucuronidation in human liver microsomes would be mainly catalyzed by UGT1A4. In the present study, trans-3'-hydroxycotinine O-glucuronidation in human liver microsomes was thoroughly characterized, since trans-3'-hydroxycotinine O-glucuronide is one of the major metabolites of nicotine. The kinetics were fitted to the Michaelis-Menten equation with a K(m) of 10.0 +/- 0.8 mM and a V(max) of 85.8 +/- 3.8 pmol/min/mg. Among 11 recombinant human UGT isoforms expressed in baculovirus-infected insect cells, UGT2B7 exhibited the highest trans-3'-hydroxycotinine O-glucuronosyltransferase activity (1.1 pmol/min/mg) followed by UGT1A9 (0.3 pmol/min/mg), UGT2B15 (0.2 pmol/min/mg), and UGT2B4 (0.2 pmol/min/mg) at a substrate concentration of 1 mM. Trans-3'-hydroxycotinine O-glucuronosyltransferase activity by recombinant UGT2B7 increased with an increase in the substrate concentration up to 16 mM (10.5 pmol/min/mg). The kinetics by recombinant UGT1A9 were fitted to the Michaelis-Menten equation with K(m) = 1.6 +/- 0.1 mM and V(max) = 0.69 +/- 0.02 pmol/min/mg of protein. Trans-3'-hydroxycotinine O-glucuronosyltransferase activities in 13 human liver microsomes ranged from 2.4 to 12.6 pmol/min/mg and were significantly correlated with valproic acid glucuronidation (r = 0.716, p < 0.01), which is catalyzed by UGT2B7, UGT1A6, and UGT1A9. Trans-3'-hydroxycotinine O-glucuronosyltransferase activity in human liver microsomes was inhibited by imipramine (a substrate of UGT1A4, IC(50) = 55 microM), androstanediol (a substrate of UGT2B15, IC(50) = 169 microM), and propofol (a substrate of UGT1A9, IC(50) = 296 microM). Interestingly, imipramine (IC(50) = 45 microM), androstanediol (IC(50) = 21 microM), and propofol (IC(50) = 41 microM) also inhibited trans-3'-hydroxycotinine O-glucuronosyltransferase activity by recombinant UGT2B7. These findings suggested that trans-3'-hydroxycotinine O-glucuronidation in human liver microsomes is catalyzed by mainly UGT2B7 and, to a minor extent, by UGT1A9.
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Affiliation(s)
- Hiroyuki Yamanaka
- Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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31
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Staines AG, Coughtrie MWH, Burchell B. N-Glucuronidation of Carbamazepine in Human Tissues Is Mediated by UGT2B7. J Pharmacol Exp Ther 2004; 311:1131-7. [PMID: 15292462 DOI: 10.1124/jpet.104.073114] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carbamazepine (CBZ) is one of the most widely prescribed anticonvulsants despite a high incidence of idiosyncratic side effects. Metabolism of CBZ is complex, and of the more than 30 metabolites identified, one of the most abundant is CBZ N-glucuronide. To date the uridine diphosphate glucuronosyltransferase (UGT) isoform responsible for the N-glucuronidation of CBZ has not been identified. We have developed a sensitive liquid chromatography/mass spectrometry assay to quantify CBZ glucuronidation, and we report that CBZ is specifically glucuronidated by human UGT2B7. Kinetics of CBZ glucuronidation in human liver, kidney, and intestine microsomes were consistent with those of recombinant UGT2B7, which displayed a Km value of 214 microM and Vmax value of 0.79 pmol/mg/min. In addition to revealing the isoform responsible for CBZ glucuronidation, this is the first example of primary amine glucuronidation by UGT2B7.
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Affiliation(s)
- Adam G Staines
- Division of Pathology and Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
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32
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Yildiz D. Nicotine, its metabolism and an overview of its biological effects. Toxicon 2004; 43:619-32. [PMID: 15109883 DOI: 10.1016/j.toxicon.2004.01.017] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Accepted: 01/05/2004] [Indexed: 10/26/2022]
Abstract
Nicotine is a naturally occurring alkaloid found in many plants. The principal sources of nicotine exposure is through the use of tobacco, nicotine containing gum and nicotine replacement therapies. Nicotine is an amine composed of pyridine and pyrrolidine rings. It has been shown that nicotine crosses biological membranes and the blood brain barrier easily. The absorbed nicotine is extensively metabolized in the liver to form a wide variety of metabolites including nicotine N'-oxide and cotinine N'-oxide. These are the products of mixed function oxidase system. Nicotine is also converted to some biologically important compounds during harvesting. Among these are the nitrosamines specific to tobacco. Nicotine has been shown to affect a wide variety of biological functions ranging from gene expression, regulation of hormone secretion and enzyme activities. The objective of this study was to overview the biological effects and metabolism of nicotine.
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Affiliation(s)
- Deniz Yildiz
- Department of Biology, Mustafa Kemal University, Antakya, Turkey.
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33
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Kuehl GE, Murphy SE. N-glucuronidation of nicotine and cotinine by human liver microsomes and heterologously expressed UDP-glucuronosyltransferases. Drug Metab Dispos 2004; 31:1361-8. [PMID: 14570768 DOI: 10.1124/dmd.31.11.1361] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Nicotine is considered the major addictive agent in tobacco. Tobacco users extensively metabolize nicotine to cotinine. Both nicotine and cotinine undergo N-glucuronidation. Human liver microsomes have been shown to catalyze the formation of these N-glucuronides. However, which UDP-glucuronosyltransferases contribute to this catalysis has not been identified. To identify these enzymes, we initially measured the rates of glucuronidation by 15 human liver microsome samples. Fourteen of the samples glucuronidated both nicotine and cotinine at rates ranging from 146 to 673 pmol/min/mg protein and 140 to 908 pmol/min/mg protein, respectively. The rates of nicotine glucuronidation and cotinine glucuronidation by these 14 samples were correlated, r = 0.97 (p < 0.0001). The glucuronidation of nicotine and cotinine by heterologously expressed UGT1A3, UGT1A4, and UGT1A9 was also determined. All three enzymes catalyzed the glucuronidation of nicotine. However, the rate of catalysis by UGT1A4 Supersomes was more than 30-fold greater than that by either UGT1A3 Supersomes or UGT1A9 Supersomes. Interestingly, when expressed per UGT1A protein, measured by a UGT1A specific antibody, cell lysate from V79-expressed UGT1A9 catalyzed nicotine glucuronidation at a rate 17-fold greater than did UGT1A9 Supersomes. UGT1A4 Supersomes also catalyzed cotinine N-glucuronidation, but at one-tenth the rate of nicotine glucuronidation. Cotinine glucuronidation by either UGT1A3 or UGT1A9 was not detected. Both propofol, a UGT1A9 substrate, and imipramine, a UGT1A4 substrate, inhibited the glucuronidation of nicotine and cotinine by human liver microsomes. Taken together, these data support a role for both UGT1A9 and UGT1A4 in the catalysis of nicotine and cotinine N-glucuronidation.
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Affiliation(s)
- Gwendolyn E Kuehl
- University of Minnesota Cancer Center, Department of Biochemistry, Molecular Biology & Biophysics, Minneapolis, Minnesota 55455, USA
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Kuuranne T, Kurkela M, Thevis M, Schänzer W, Finel M, Kostiainen R. Glucuronidation of anabolic androgenic steroids by recombinant human UDP-glucuronosyltransferases. Drug Metab Dispos 2003; 31:1117-24. [PMID: 12920167 DOI: 10.1124/dmd.31.9.1117] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A multidimensional study on the glucuronidation of anabolic androgenic steroids and their phase I metabolites by 11 recombinant human UDP-glucuronosyltransferases (UGTs) was carried out using liquid chromatographic-tandem mass spectrometric analyses. Large differences between the enzymes with respect to the conjugation profiles of the 11 tested aglycones were detected. Two UGTs, 1A6 and 1A7, did not exhibit measurable activity toward any of the aglycones that were examined in this study. Regioselectivity was demonstrated by UGTs 1A8, 1A9, and 2B15 that preferentially catalyzed hydroxyl glucuronidation at the 17beta-position. Most of the other enzymes glucuronidated hydroxyl groups at both the 3alpha- and the 17beta-positions. Clear stereoselectivity was observed in glucuronidation of diastereomeric nandrolone metabolites (5alpha-estran-3alpha-ol-17-one and 5beta-estran-3alpha-ol-17-one), whereas such specificity was not seen when analogous methyltestosterone metabolites were assayed. UGTs 1A1, 1A3, 1A4, 1A8, 1A9, 1A10, 2B4, 2B7, and 2B15 readily glucuronidated 5alpha-androstane-3alpha,17beta-diol, but none of them exhibited methyltestosterone glucuronidation activity. In agreement with the latter observations, we found that the methyltestosterone glucuronidation activity of human liver microsomes is extremely low, whereas in induced rat liver microsomes it was significantly higher. The homology among UGTs 1A7 to 1A10 at the level of amino acid sequence is very high, and it was thus surprising to find large differences in their activity toward this set of aglycones. Furthermore, the high activity of UGT1A8 and 1A10 toward some of the substrates indicates that extrahepatic enzymes might play a role in the metabolism of anabolic androgenic steroids.
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Affiliation(s)
- Tiia Kuuranne
- Division of Pharmaceutical Chemistry, University of Helsinki, Finland
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35
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Nakajima M, Sakata N, Ohashi N, Kume T, Yokoi T. Involvement of multiple UDP-glucuronosyltransferase 1A isoforms in glucuronidation of 5-(4'-hydroxyphenyl)-5-phenylhydantoin in human liver microsomes. Drug Metab Dispos 2002; 30:1250-6. [PMID: 12386132 DOI: 10.1124/dmd.30.11.1250] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In humans, orally administered phenytoin, 5,5-diphenylhydantoin, is mainly excreted as 5-(4'-hydroxyphenyl)-5-phenylhydantoin (4'-HPPH) O-glucuronide. Phenytoin is oxidized to 4'-HPPH by CYP2C9 and to a minor extent by CYP2C19, and then 4'-HPPH is metabolized to 4'-HPPH O-glucuronide by UDP-glucuronosyltransferase (UGT). In the present study, 4'-HPPH O-glucuronidation in human liver microsomes was investigated. The metabolite formed by incubation with human liver microsomes, 4'-HPPH, and UDP-glucuronic acid was identified as 4'-HPPH O-glucuronide by liquid chromatography-tandem mass spectrometry analysis. The 4'-HPPH O-glucuronosyltransferase activity in human liver microsomes was not saturated at concentrations up to 500 microM of 4'-HPPH. Any commercially available recombinant human UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT2B7, and UGT2B15) expressed in baculovirus-infected insect cells did not show detectable 4'-HPPH O-glucuronide. The 4'-HPPH O-glucuronidation in pooled human liver microsomes was inhibited by beta-estradiol as a typical substrate for UGT1A1 (IC(50) = 21.1 microM) and imipramine as a typical substrate for UGT1A4 (IC(50) = 57.7 microM). The inhibitory effects of propofol as a specific substrate for UGT1A9 (IC(50) = 167.1 microM) and emodin as a substrate for UGT1A8 and UGT1A10 (IC(50) = 287.6 microM) were not prominent. The interindividual difference in the 4'-HPPH O-glucuronidation in 14 human liver microsomes was 28.5-fold (0.023-0.656 nmol/min/mg of protein). The 4'-HPPH O-glucuronosyltransferase activity in 11 human liver microsomes was significantly (r = 0.609, P < 0.05) correlated with the 4-nitrophenol glucuronosyltransferase activity, which is catalyzed by UGT1A6 and UGT1A9. These results suggest that multiple UGT1As such as UGT1A1, UGT1A4, UGT1A6, and UGT1A9 are involved in 4'-HPPH O-glucuronidation in human liver microsomes, although the percentage contribution of each UGT1A could not be estimated. Large interindividual differences in the glucuronidation of 4'-HPPH might be responsible for the nonlinearity of the phenytoin plasma concentration or adverse reactions in humans.
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Affiliation(s)
- Miki Nakajima
- Division of Drug Metabolism, Faculty of Pharmaceutical Sciences, Kanazawa University, Kanazawa, Japan
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