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Sex and Estrous Cycle Differences in Analgesia and Brain Oxycodone Levels. Mol Neurobiol 2021; 58:6540-6551. [PMID: 34581987 DOI: 10.1007/s12035-021-02560-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/10/2021] [Indexed: 12/29/2022]
Abstract
Sex differences in opioid analgesia occur in rodents and humans, and could be due to differences in drug and metabolite levels. Thus, we investigated the sex and cycle differences in analgesia (nociception) from oxycodone in rats and related these to sex and cycle differences in brain and plasma oxycodone and metabolite levels. Since numerous opioids are CYP2D enzyme substrates and variation in CYP2D alters opioid drug levels and response, we also initiated studies to see if the sex and cycle differences observed might be due to differences in brain CYP2D activity. Across oxycodone doses, females in diestrus had higher analgesia (using tail flick latency) compared to males and females in estrus; we also demonstrated a direct effect of estrous cycle on analgesia within females. Consistent with the analgesia, females in diestrus had highest brain oxycodone levels (assessed using microdialysis) compared to males and females in estrus. Analgesia correlated with brain oxycodone, but not brain oxymorphone or noroxycodone levels, or plasma drug or metabolite levels. Propranolol (a CYP2D mechanism-based inhibitor), versus vehicle pre-treatments, increased brain oxycodone, and decreased brain oxymorphone/oxycodone drug level ratios (an in vivo CYP2D activity phenotype in the brain) in males and females in estrus, but not in females in diestrus. Brain oxymorphone/oxycodone inversely correlated with analgesia. Together, both sex and estrous cycle impact oxycodone analgesia and brain oxycodone levels, likely through regulation of brain CYP2D oxycodone metabolism. As CYP2D6 is expressed in human brain, perhaps similar sex and cycle influences also occur in humans.
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Lopes-Coelho F, Martins F, Hipólito A, Mendes C, Sequeira CO, Pires RF, Almeida AM, Bonifácio VDB, Pereira SA, Serpa J. The Activation of Endothelial Cells Relies on a Ferroptosis-Like Mechanism: Novel Perspectives in Management of Angiogenesis and Cancer Therapy. Front Oncol 2021; 11:656229. [PMID: 34041026 PMCID: PMC8141735 DOI: 10.3389/fonc.2021.656229] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/21/2021] [Indexed: 12/12/2022] Open
Abstract
The activation of endothelial cells (ECs) is a crucial step on the road map of tumor angiogenesis and expanding evidence indicates that a pro-oxidant tumor microenvironment, conditioned by cancer metabolic rewiring, is a relevant controller of this process. Herein, we investigated the contribution of oxidative stress-induced ferroptosis to ECs activation. Moreover, we also addressed the anti-angiogenic effect of Propranolol. We observed that a ferroptosis-like mechanism, induced by xCT inhibition with Erastin, at a non-lethal level, promoted features of ECs activation, such as proliferation, migration and vessel-like structures formation, concomitantly with the depletion of reduced glutathione (GSH) and increased levels of oxidative stress and lipid peroxides. Additionally, this ferroptosis-like mechanism promoted vascular endothelial cadherin (VE-cadherin) junctional gaps and potentiated cancer cell adhesion to ECs and transendothelial migration. Propranolol was able to revert Erastin-dependent activation of ECs and increased levels of hydrogen sulfide (H2S) underlie the mechanism of action of Propranolol. Furthermore, we tested a dual-effect therapy by promoting ECs stability with Propranolol and boosting oxidative stress to induce cancer cell death with a nanoformulation comprising selenium-containing chrysin (SeChry) encapsulated in a fourth generation polyurea dendrimer (SeChry@PUREG4). Our data showed that novel developments in cancer treatment may rely on multi-targeting strategies focusing on nanoformulations for a safer induction of cancer cell death, taking advantage of tumor vasculature stabilization.
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Affiliation(s)
- Filipa Lopes-Coelho
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Filipa Martins
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Ana Hipólito
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Cindy Mendes
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Catarina O Sequeira
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Rita F Pires
- iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - António M Almeida
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,Hematology, Hospital da Luz, Lisboa, Portugal
| | - Vasco D B Bonifácio
- iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Sofia A Pereira
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Jacinta Serpa
- Unidade de Investigação em Patobiologia Molecular (UIPM), Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisboa, Portugal.,CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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Ozawa S, Miura T, Terashima J, Habano W, Ishida S. Recent Progress in Prediction Systems for Drug-induced Liver Injury Using in vitro Cell Culture. Drug Metab Lett 2020; 14:25-40. [PMID: 33267768 DOI: 10.2174/1872312814666201202112610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/26/2020] [Accepted: 11/03/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND In order to avoid drug-induced liver injury (DILI), in vitro assays, which enable the assessment of both metabolic activation and immune reaction processes that ultimately result in DILI, are needed. OBJECTIVE In this study, the recent progress in the application of in vitro assays using cell culture systems is reviewed for potential DILI-causing drugs/xenobiotics and a mechanistic study on DILI, as well as for the limitations of in vitro cell culture systems for DILI research. METHODS Information related to DILI was collected through a literature search of the PubMed database. RESULTS The initial biological event for the onset of DILI is the formation of cellular protein adducts after drugs have been metabolically activated by drug metabolizing enzymes. The damaged peptides derived from protein adducts lead to the activation of CD4+ helper T lymphocytes and recognition by CD8+ cytotoxic T lymphocytes, which destroy hepatocytes through immunological reactions. Because DILI is a major cause of drug attrition and drug withdrawal, numerous in vitro systems consisting of hepatocytes and immune/inflammatory cells, or spheroids of human primary hepatocytes containing non-parenchymal cells have been developed. These cellular-based systems have identified DILIinducing drugs with approximately 50% sensitivity and 90% specificity. CONCLUSION Different co-culture systems consisting of human hepatocyte-derived cells and other immune/inflammatory cells have enabled the identification of DILI-causing drugs and of the actual mechanisms of action.
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Affiliation(s)
- Shogo Ozawa
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Toshitaka Miura
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Jun Terashima
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Wataru Habano
- Department of Clinical Pharmaceutical Sciences, Division of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Yahaba. Japan
| | - Seiichi Ishida
- Department of Pharmacology, National Institute of Health Sciences, Kawasaki. Japan
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Tolledo C, Stocco MR, Miksys S, Gonzalez FJ, Tyndale RF. Human CYP2D6 Is Functional in Brain In Vivo: Evidence from Humanized CYP2D6 Transgenic Mice. Mol Neurobiol 2020; 57:2509-2520. [PMID: 32189192 DOI: 10.1007/s12035-020-01896-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/02/2020] [Indexed: 01/08/2023]
Abstract
CYP2D metabolizes many drugs that act within the brain, and variable expression of CYP2D in the brain may alter local drug and metabolite levels sufficiently to affect behavioral responses. Transgenic mice that express human CYP2D6 (TG) were compared to wild type mice (WT). Following selective inhibition of human CYP2D6 in TG brain, we demonstrated in vivo that human CYP2D6 in the brain was sufficient to alter a drug-induced behavioral response. After a 4-h pre-treatment with intracerebroventricular (i.c.v.) propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo, but not in vitro, was reduced in WT brain. After a 24-h pre-treatment with i.c.v. propranolol, CYP2D activity in vivo and in vitro was reduced in TG brain, whereas CYP2D activity in vivo and in vitro was not changed in WT brain. These results indicate that i.c.v. propranolol irreversibly inhibited human CYP2D6 in TG brain but not mouse CYP2D in TG and WT brain. Pre-treatments with propranolol did not change liver CYP2D activity in vivo or in vitro. Furthermore, 24-h pre-treatment with i.c.v. propranolol resulted in a significant decrease of the haloperidol-induced catalepsy response in TG, but not in WT, without changing serum haloperidol levels in either mouse line. These studies reveal a new tool to selectively and irreversibly inhibit human CYP2D6 in TG brain and indicate that human CYP2D6 has a functional role within the brain sufficient to impact the central nervous system response from peripherally administered drugs.
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Affiliation(s)
- Cole Tolledo
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Marlaina R Stocco
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Sharon Miksys
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada. .,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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Tolledo EC, Miksys S, Gonzalez FJ, Tyndale RF. Propranolol is a mechanism-based inhibitor of CYP2D and CYP2D6 in humanized CYP2D6-transgenic mice: Effects on activity and drug responses. Br J Pharmacol 2020; 177:701-712. [PMID: 31648367 PMCID: PMC7012948 DOI: 10.1111/bph.14884] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/16/2019] [Accepted: 09/13/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Genetics and drug interactions contribute to large interindividual variation in human CYP2D6 activity. Here, we have characterized propranolol inhibition of human and mouse CYP2D using transgenic (TG) mice, which express both mouse CYP2D and human CYP2D6, and wild-type (WT) mice. Our purpose was to develop a method for in vivo manipulation of CYP2D6 enzyme activity which could be used to investigate the role of CYP2D6 in drug-induced behaviours. EXPERIMENTAL APPROACH Dextromethorphan metabolism to dextrorphan was used to measure CYP2D activity and to characterize propranolol inhibition in vitro and in vivo. Effects of propranolol pretreatment (24 hr) on serum levels of the CYP2D6 substrate haloperidol and haloperidol-induced catalepsy were also studied. KEY RESULTS Dextrorphan formation velocity in vitro was threefold higher in liver microsomes of TG compared to WT mice. Propranolol acted as a mechanism-based inhibitor (MBI), inactivating CYP2D in liver microsomes from TG and WT mice, and humans. Pretreatment (24 hr) of TG and WT mice with 20 mg·kg-1 intraperitoneal propranolol reduced dextrorphan formation in vivo and by liver microsomes in vitro. Serum haloperidol levels and catalepsy were increased. CONCLUSIONS AND IMPLICATIONS Propranolol was a potent MBI of dextrorphan formation in liver microsomes from TG and WT mice, and humans. The inhibition parameters in TG overlapped with those in WT mice and in humans. Inhibition of CYP2D with propranolol in vivo in TG and WT mice altered drug responses, allowing further investigation of variations in CYP2D6 on drug interactions and drug responses.
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Affiliation(s)
- Edgor Cole Tolledo
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Department of Pharmacology & Toxicology, Department of PsychiatryUniversity of TorontoTorontoOntarioCanada
| | - Sharon Miksys
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Department of Pharmacology & Toxicology, Department of PsychiatryUniversity of TorontoTorontoOntarioCanada
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer InstituteNational Institutes of HealthBethesdaMarylandUSA
| | - Rachel F. Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Department of Pharmacology & Toxicology, Department of PsychiatryUniversity of TorontoTorontoOntarioCanada
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Abstract
BACKGROUND Tobacco smoking rates in depressive patients are higher compared with the general population. Smoking was demonstrated to accelerate the metabolism of different drugs metabolized by CYP1A2, but possibly also by CYP2C19 and CYP3A4. The principle aim of the present investigation from 2015 to 2018 was to determine the differences in the pharmacokinetics of escitalopram between smokers and nonsmokers. METHODS A group of nonsmokers (n = 88) was compared with smokers (n = 36), both receiving escitalopram, using the Mann-Whitney U test. Linear regression analysis was used to account for the impact of escitalopram dose, age, and sex in addition to smoking on the steady-state serum concentration of escitalopram. RESULTS Smokers received by mean 17.6% higher doses of escitalopram (P = 0.026) but showed 31.9% lower serum concentrations (P = 0.031). To control for confounders, linear regression analysis showed that dose (P < 0.001), sex (P = 0.03), and smoking tobacco (P = 0.027) did significantly influence serum concentrations of escitalopram with higher levels in women and nonsmokers. CONCLUSIONS Notwithstanding higher daily doses, smokers had significantly lower serum concentrations of escitalopram. In concordance with previous results, besides CYP1A2, a possible induction of CYP2C19 and CYP3A4 by tobacco smoke, resulting in lower serum concentrations of escitalopram in smokers than in nonsmokers, is suggested. Therefore, to provide personalized therapy, clinicians should consider smoking status and inform patients on the interactions of smoking and escitalopram metabolism.
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McMillan DM, Tyndale RF. Inducing rat brain CYP2D with nicotine increases the rate of codeine tolerance; predicting the rate of tolerance from acute analgesic response. Biochem Pharmacol 2017; 145:158-168. [DOI: 10.1016/j.bcp.2017.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 08/18/2017] [Indexed: 01/08/2023]
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Tfelt-Hansen P, Ågesen FN, Pavbro A, Tfelt-Hansen J. Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine. CNS Drugs 2017; 31:389-403. [PMID: 28405886 DOI: 10.1007/s40263-017-0430-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.
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Affiliation(s)
- Peer Tfelt-Hansen
- Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Frederik Nybye Ågesen
- Department of Cardiology, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
| | - Agniezka Pavbro
- Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Jacob Tfelt-Hansen
- Department of Cardiology, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
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Li J, Xie M, Wang X, Ouyang X, Wan Y, Dong G, Yang Z, Yang J, Yue J. Sex hormones regulate cerebral drug metabolism via brain miRNAs: down-regulation of brain CYP2D by androgens reduces the analgesic effects of tramadol. Br J Pharmacol 2015; 172:4639-54. [PMID: 26031356 DOI: 10.1111/bph.13206] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 05/13/2015] [Accepted: 05/21/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Brain cytochrome P450 2D (CYP2D) metabolises exogenous neurotoxins, endogenous substances and neurotransmitters. Brain CYP2D can be regulated in an organ-specific manner, but the possible regulatory mechanisms are poorly understood. We investigated the involvement of miRNAs in the selective regulation of brain CYP2D by testosterone and the corresponding alteration of the pharmacological profiles of tramadol by testosterone. EXPERIMENTAL APPROACH The regulation of CYP2D and brain-enriched miRNAs by testosterone was investigated using SH-SY5Y cells, U251 cells, and HepG2 cells as well as orchiectomized growth hormone receptor knockout (GHR-KO) mice and rats. Concentration-time curves of tramadol in rat brain were determined using a microdialysis technique. The analgesic action of tramadol was assessed by the tail-flick test in rats. KEY RESULTS miR-101 and miR-128-2 bound the 3'-untranslated region of the CYP2D6 mRNA and decreased its level. Testosterone decreased CYP2D6 catalytic function via the up-regulation of miR-101 and miR-128-2 in SH-SY5Y and U251 cells, but not in HepG2 cells. Orchiectomy decreased the levels of miR-101 and miR-128-2 in the hippocampus of male GHR-KO mice, indicating that androgens regulate miRNAs directly, not via the alteration of growth hormone secretion patterns. Changes in the pharmacokinetic and pharmacodynamic profiles of tramadol by orchiectomy was attenuated by either testosterone supplementation or a specific brain CYP2D inhibitor. CONCLUSIONS AND IMPLICATIONS The selective regulation of brain CYP2D via brain-enriched miRNAs, following changes in androgen levels, such as in testosterone therapy, androgen deprivation therapy and/or ageing may alter the response to centrally active substances.
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Affiliation(s)
- Jie Li
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Mengmeng Xie
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Xiaoshuang Wang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Xiufang Ouyang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Yu Wan
- Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Guicheng Dong
- Baotou Teachers' College, Inner Mongolia University of Science and Technology, Baotou, China
| | - Zheqiong Yang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Jing Yang
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Jiang Yue
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China
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McMillan DM, Tyndale RF. Nicotine Increases Codeine Analgesia Through the Induction of Brain CYP2D and Central Activation of Codeine to Morphine. Neuropsychopharmacology 2015; 40:1804-12. [PMID: 25630571 PMCID: PMC4916647 DOI: 10.1038/npp.2015.32] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 01/22/2023]
Abstract
CYP2D metabolically activates codeine to morphine, which is required for codeine analgesia. Permeability across the blood-brain barrier, and active efflux, suggests that initial morphine in the brain after codeine is due to brain CYP2D metabolism. Human CYP2D is higher in the brains, but not in the livers, of smokers and 7-day nicotine treatment induces rat brain, but not hepatic, CYP2D. The role of nicotine-induced rat brain CYP2D in the central metabolic activation of peripherally administered codeine and resulting analgesia was investigated. Rats received 7-day nicotine (1 mg/kg subcutaneously) and/or a single propranolol (CYP2D mechanism-based inhibitor; 20 μg intracerebroventricularly) pretreatment, and then were tested for analgesia and drug levels following codeine (20 mg/kg intraperitoneally) or morphine (3.5 mg/kg intraperitoneally), matched for peak analgesia. Nicotine increased codeine analgesia (1.59X AUC(0-30 min) vs vehicle; p<0.001), while propranolol decreased analgesia (0.56X; p<0.05); co-pretreatment was similar to vehicle controls (1.23X; p>0.1). Nicotine increased, while propranolol decreased, brain, but not plasma, morphine levels, and analgesia correlated with brain (p<0.02), but not plasma (p>0.4), morphine levels after codeine. Pretreatments did not alter baseline or morphine analgesia. Here we show that brain CYP2D alters drug response despite the presence of substantial first-pass metabolism of codeine and further that nicotine induction of brain CYP2D increases codeine response in vivo. Thus variation in brain CYP2D activity, due to genetics or environment, may contribute to individual differences in response to centrally acting substrates. Exposure to nicotine may increase central drug metabolism, not detected peripherally, contributing to altered drug efficacy, onset time, and/or abuse liability.
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Affiliation(s)
- Douglas M McMillan
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) and Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) and Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada,Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Medical Sciences Building Room 4326, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada, Tel: 416 978 6374, Fax: 416 978 6395, E-mail:
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11
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Lai B, Nagy G, Garate JA, Oostenbrink C. Entropic and enthalpic contributions to stereospecific ligand binding from enhanced sampling methods. J Chem Inf Model 2014; 54:151-8. [PMID: 24372516 PMCID: PMC3904767 DOI: 10.1021/ci4006657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
The
stereoselective binding of R- and S-propranolol to the metabolic enzyme cytochrome P450 2D6
and its mutant F483A was studied using various computational approaches.
Previously reported free-energy differences from Hamiltonian replica
exchange simulations, combined with thermodynamic integration, are
compared to the one-step perturbation approach, combined with local-elevation
enhanced sampling, and an excellent agreement between methods was
obtained. Further, the free-energy differences are interpreted in
terms of enthalpic and entropic contributions where it is shown that
exactly compensating contributions obscure a molecular interpretation
of differences in the affinity while various reduced terms allow a
more detailed analysis, which agree with heuristic observations on
the interactions.
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Affiliation(s)
- Balder Lai
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation at BOKU- University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
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12
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Zhou K, Khokhar JY, Zhao B, Tyndale RF. First demonstration that brain CYP2D-mediated opiate metabolic activation alters analgesia in vivo. Biochem Pharmacol 2013; 85:1848-55. [PMID: 23623752 DOI: 10.1016/j.bcp.2013.04.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 04/13/2013] [Accepted: 04/16/2013] [Indexed: 12/13/2022]
Abstract
The response to centrally acting drugs is highly variable between individuals and does not always correlate with plasma drug levels. Drug-metabolizing CYP enzymes in the brain may contribute to this variability by affecting local drug and metabolite concentrations. CYP2D metabolizes codeine to the active morphine metabolite. We investigated the effect of inhibiting brain, and not liver, CYP2D activity on codeine-induced analgesia. Rats received intracerebroventricular injections of CYP2D inhibitors (20 μg propranolol or 40 μg propafenone) or vehicle controls. Compared to vehicle-pretreated rats, inhibitor-pretreated rats had: (a) lower analgesia in the tail-flick test (p<0.05) and lower areas under the analgesia-time curve (p<0.02) within the first hour after 30 mg/kg subcutaneous codeine, (b) lower morphine concentrations and morphine to codeine ratios in the brain (p<0.02 and p<0.05, respectively), but not in plasma (p>0.6 and p>0.7, respectively), tested at 30 min after 30 mg/kg subcutaneous codeine, and (c) lower morphine formation from codeine ex vivo by brain membranes (p<0.04), but not by liver microsomes (p>0.9). Analgesia trended toward a correlation with brain morphine concentrations (p=0.07) and correlated with brain morphine to codeine ratios (p<0.005), but not with plasma morphine concentrations (p>0.8) or plasma morphine to codeine ratios (p>0.8). Our findings suggest that brain CYP2D affects brain morphine levels after peripheral codeine administration, and may thereby alter codeine's therapeutic efficacy, side-effect profile and abuse liability. Brain CYPs are highly variable due to genetics, environmental factors and age, and may therefore contribute to interindividual variation in the response to centrally acting drugs.
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Affiliation(s)
- Kaidi Zhou
- Departments of Pharmacology & Toxicology and Psychiatry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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13
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Nakayama S, Takakusa H, Watanabe A, Miyaji Y, Suzuki W, Sugiyama D, Shiosakai K, Honda K, Okudaira N, Izumi T, Okazaki O. Combination of GSH Trapping and Time-Dependent Inhibition Assays as a Predictive Method of Drugs Generating Highly Reactive Metabolites. Drug Metab Dispos 2011; 39:1247-54. [DOI: 10.1124/dmd.111.039180] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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14
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Yeung CK, Fujioka Y, Hachad H, Levy RH, Isoherranen N. Are circulating metabolites important in drug-drug interactions?: Quantitative analysis of risk prediction and inhibitory potency. Clin Pharmacol Ther 2010; 89:105-13. [PMID: 21124313 DOI: 10.1038/clpt.2010.252] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The potential of metabolites to contribute to drug-drug interactions (DDIs) is not well defined. The aim of this study was to determine the quantitative role of circulating metabolites in inhibitory DDIs in vivo. The area under the plasma concentration-time curve (AUC) data related to at least one circulating metabolite was available for 71% of the 102 inhibitor drugs identified. Of the 80 metabolites characterized at steady state, 78% had AUCs >10% of that of the parent drug. A comparison of the inhibitor concentration/inhibition constant ([I]/K(i)) ratios of metabolites and the respective parent drugs showed that 17 of the 21 (80%) reversible inhibitors studied had metabolites that were likely to contribute to in vivo DDIs, with some metabolites predicted to have inhibitory effects greater than those of the parent drug. The in vivo drug interaction risks associated with amiodarone, bupropion, and sertraline could be identified from in vitro data only, when data pertaining to metabolites were included in the predictions. In conclusion, cytochrome P450 (CYP) inhibitors often have circulating metabolites that contribute to clinically observed CYP inhibition.
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Affiliation(s)
- C K Yeung
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
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15
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Tonn GR, Wong SG, Wong SC, Johnson MG, Ma J, Cho R, Floren LC, Kersey K, Berry K, Marcus AP, Wang X, Van Lengerich B, Medina JC, Pearson PG, Wong BK. An Inhibitory Metabolite Leads to Dose- and Time-Dependent Pharmacokinetics of (R)-N-{1-[3-(4-Ethoxy-phenyl)-4-oxo-3,4-dihydro-pyrido[2,3-d]pyrimidin-2-yl]-ethyl}-N-pyridin-3-yl-methyl-2-(4-trifluoromethoxy-phenyl)-acetamide (AMG 487) in Human Subjects After Multiple Dosing. Drug Metab Dispos 2008; 37:502-13. [DOI: 10.1124/dmd.108.021931] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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16
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Turpeinen M, Korhonen LE, Tolonen A, Uusitalo J, Juvonen R, Raunio H, Pelkonen O. Cytochrome P450 (CYP) inhibition screening: Comparison of three tests. Eur J Pharm Sci 2006; 29:130-8. [PMID: 16890411 DOI: 10.1016/j.ejps.2006.06.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2006] [Revised: 05/09/2006] [Accepted: 06/20/2006] [Indexed: 11/19/2022]
Abstract
There are several different experimental systems for screening of in vitro inhibitory potency of drugs under development. In this study we compared three different types of cytochrome P450 (CYP) inhibition tests: the traditional single substrate assays, the fluorescent probe method with recombinant human CYPs, and a novel n-in-one technique. All major hepatic drug-metabolizing CYPs were included (1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4). Six compounds (sotalol, propranolol, citalopram, fluoxetine, oxazepam and diazepam) were selected for detailed comparisons. The IC50 values of each of these compounds were measured using the three assay types. The inhibitory potencies of these model drugs were generally within the same order of magnitude and followed similar inhibition profiles in all the assay types. Clinically observed inhibitory interactions, or lack thereof, were predictable with all three assays. Comparison of potencies of 'diagnostic' inhibitors revealed also some notable differences between the assays, especially regarding CYP2E1. The potency of inhibitors towards CYP3A4 was dependent on the substrate and reaction measured. Generally all three assays gave reasonably comparable results, although some unexplained differences were also noted.
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Affiliation(s)
- Miia Turpeinen
- Department of Pharmacology and Toxicology, University of Oulu, P.O. Box 5000, 90014 Oulu, Finland.
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17
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Oselin K, Anier K, Tamm R, Kallassalu K, Mäeorg U. Determination of thiopurine S-methyltransferase (TPMT) activity by comparing various normalization factors: Reference values for Estonian population using HPLC-UV assay. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 834:77-83. [PMID: 16517227 DOI: 10.1016/j.jchromb.2006.02.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 02/10/2006] [Accepted: 02/17/2006] [Indexed: 10/24/2022]
Abstract
Thiopurine S-methyltransferase (TPMT; EC 2.1.1.67) is the key enzyme in the metabolism of thiopurine drugs. Determination of TPMT activity has been used for the individualization of thiopurine dose. We developed HPLC-UV assay for the determination of TPMT activity in human erythrocytes using 6-mercaptopurine as a substrate. Various extraction and chromatographic conditions were compared. In-house developed extraction with acetonitrile provided the lowest limit of quantification. TPMT activity was determined in 99 previously genotyped healthy Estonians. TPMT activity was expressed as the formation of 6-methylmercaptopurine ng/ml/h and normalized either to haemoglobin, haematocrit, erythrocyte count or protein content. The receiver-operating characteristic curve analysis revealed similar accuracy values for TPMT activity in predicting heterozygous and wild type individuals for each method of calculation. In healthy Estonians, TPMT activity varied from 21.5 to 129.6 ng/ml/h. For heterozygous individuals (n = 18), TPMT activity was 48.1 +/- 11.7 ng/ml/h. Wild type individuals (n = 81) revealed significantly higher TPMT activity 79.3 +/- 20.7 ng/ml/h (P < 0.001). This sensitive HPLC assay for quantitative determination of TPMT activity could easily be used in clinical settings. Under constant experimental conditions for haemolysate preparation no normalization is required.
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Affiliation(s)
- Kersti Oselin
- Department of Pharmacology, Tartu University, 51014 Tartu, Estonia.
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18
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Isohanni MH, Neuvonen PJ, Olkkola KT. Effect of Itraconazole on the Pharmacokinetics of Inhaled Lidocaine. ACTA ACUST UNITED AC 2004; 95:120-3. [PMID: 15447735 DOI: 10.1111/j.1742-7843.2004.950303.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Lidocaine is metabolized by cytochrome P450 3A4 and 1A2 enzymes (CYP3A4 and CYP1A2) in vitro. However, their relative contribution to the elimination of lidocaine depends on lidocaine concentration. We have studied the effect of a potent CYP3A4 inhibitor, itraconazole, on the pharmacokinetics of inhaled lidocaine in ten healthy volunteers using a randomized, two-phase cross-over study design. The interval between the phases was four weeks. The subjects were given orally itraconazole (200 mg once a day) or placebo for four days. On day 4, each subject inhaled a single dose of 1.5 mg/kg of lidocaine by nebulizer. Plasma samples were collected until 10 hr and the concentrations of lidocaine and its major metabolite monoethylglycinexylidide were measured by gas chromatography. The areas under the lidocaine and monoethylglycinexylidide concentration time curves were similar during both phases. No statistically significant differences were observed in any of the pharmacokinetic parameters; peak concentrations, concentration peak times or elimination half-lives of lidocaine or monoethylglycinexylidide. The clinical implication of this study is that no lidocaine dosage adjustments are necessary if it is used to prepare the airway prior to endoscopic procedures or intubation in patients using itraconazole or other inhibitors of CYP3A4.
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Affiliation(s)
- Mika H Isohanni
- Department of Anaesthesia, Diacor Hospital, Helsinki, Finland.
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19
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Abstract
In the elderly concomitant use of several drugs (polypharmacy) is very common. Thus, the risk for drug interactions might be increased in this population. Since most drugs are hepatically eliminated by various metabolic pathways, liver function has to be considered as an additional factor modifying drug response. This chapter focuses on the hepatic mechanisms of interactions, especially on various inhibitors and inducers of the most important cytochrome P450 isoenzymes involved in drug metabolism. In addition, age-dependent changes in liver function are addressed. Based on pharmacokinetic results with different probe drugs, some inconsistencies in this area are discussed. The most important metabolic drug-drug interactions are independent of the age of the patients. However, since elderly patients consume a greater proportional share of drugs, they represent a population at risk for interactions. Awareness of this clinical problem may help to diminish those risks.
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Affiliation(s)
- C Herrlinger
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Auerbachstrasse 112, D-70376 Stuttgart, Germany
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20
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Isohanni MH, Neuvonen PJ, Olkkola KT. Effect of erythromycin and itraconazole on the pharmacokinetics of oral lignocaine. PHARMACOLOGY & TOXICOLOGY 1999; 84:143-6. [PMID: 10193676 DOI: 10.1111/j.1600-0773.1999.tb00890.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Lignocaine is metabolized by cytochrome P450 3A4 enzyme (CYP3A4), and has a moderate to high extraction ratio resulting in oral bioavailability of 30%. We have studied the possible effect of two inhibitors of CYP3A4, erythromycin and itraconazole, on the pharmacokinetics of oral lignocaine in nine volunteers using a cross-over study design. The subjects were given erythromycin orally (500 mg three times a day), itraconazole (200 mg once a day) or placebo for four days. On day 4, each subject ingested a single dose of 1 mg/kg of oral lignocaine. Plasma samples were collected until 10 hr and concentrations of lignocaine and its major metabolite, monoethylglycinexylidide were measured by gas chromatography. Both erythromycin and itraconazole increased the area under the lignocaine plasma concentration-time curve [AUC(0-infinity)] and lignocaine peak concentrations by 40-70% (P<0.05). Compared to placebo and itraconazole, erythromycin increased monoethylglycinexylidide peak concentrations by approximately 40% (P<0.01) and AUC(0-infinity) by 60% (P<0.01). The clinical implication of this study is that erythromycin and itraconazole may significantly increase the plasma concentrations and toxicity of oral lignocaine. The extent of the interaction of lignocaine with these CYP3A4 inhibitors was, however, less than that of, e.g. midazolam or buspirone, and it did not correlate with the CYP3A4 inhibiting potency of erythromycin and itraconazole.
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Affiliation(s)
- M H Isohanni
- Department of Anaesthesia, University of Helsinki, Finland
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Tran A, Rey E, Pons G, Rousseau M, d'Athis P, Olive G, Mather GG, Bishop FE, Wurden CJ, Labroo R, Trager WF, Kunze KL, Thummel KE, Vincent JC, Gillardin JM, Lepage F, Levy RH. Influence of stiripentol on cytochrome P450-mediated metabolic pathways in humans: in vitro and in vivo comparison and calculation of in vivo inhibition constants. Clin Pharmacol Ther 1997; 62:490-504. [PMID: 9390105 DOI: 10.1016/s0009-9236(97)90044-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The spectrum of cytochrome P450 inhibition of stiripentol, a new anticonvulsant, was characterized in vitro and in vivo. METHODS Stiripentol was incubated in vitro with (R)-warfarin, coumarin, (S)-warfarin, (S)-mephenytoin, bufuralol, p-nitrophenol, and carbamazepine as probes for CYPs 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4, respectively. Caffeine demethylation and the 6 beta-hydroxycortisol/cortisol ratio were monitored in vivo before and after 14 days of treatment with stiripentol as measures of CYP1A2 and CYP3A4 activity, and dextromethorphan O- and N-demethylation were used to measure CYP2D6 and CYP3A4 activity, respectively. In vivo inhibition constants for CYP3A4 were calculated with use of data that previously documented the interaction between stripentol and carbamazepine. RESULTS In vitro, stiripentol inhibited CYPs 1A2, 2C9, 2C19, 2D6, and 3A4, with inhibition constant values at or slightly higher than therapeutic (total) concentrations of stiripentol, but it did not inhibit CYPs 2A6 and 2E1 even at tenfold therapeutic concentrations. In vivo inhibition of caffeine demethylation and dextromethorphan N-demethylation were consistent with inhibition of CYP1A2 and CYP3A4, respectively. The 6 beta-hydroxycortisol/cortisol ratio did not provide a reliable index of CYP3A4 inhibition. Inhibition of CYP2D6-mediated O-demethylation was not observed in vivo. With use of carbamazepine, in vivo inhibition constants for CYP3A4 ranged between 12 and 35 mumol/L, whereas the corresponding in vitro value was 80 mumol/L. CONCLUSIONS Stiripentol appears to inhibit several CYP450 enzymes in vitro and in vivo. In vivo inhibition constants show that stiripentol inhibition of CYP3A4 is linearly related to plasma concentration in patients with epilepsy.
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Affiliation(s)
- A Tran
- Département de Pharmacologie Périnatale et Pédiatrique, Hôpital Saint Vincent de Paul-Université René Descartes Paris V
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Yoshimoto K, Echizen H, Chiba K, Tani M, Ishizaki T. Identification of human CYP isoforms involved in the metabolism of propranolol enantiomers--N-desisopropylation is mediated mainly by CYP1A2. Br J Clin Pharmacol 1995; 39:421-31. [PMID: 7640150 PMCID: PMC1365131 DOI: 10.1111/j.1365-2125.1995.tb04472.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. Studies using human liver microsomes and six recombinant human CYP isoforms (i.e. CYP1A2, 2A6, 2B6, 2D6, 2E1 and 3A4) were performed to identify the cytochrome P450 (CYP) isoform(s) involved in the ring 4-hydroxylation and side-chain N-desisopropylation of propranolol enantiomers in humans. 2. alpha-Naphthoflavone and 7-ethoxyresorufin (selective inhibitors of CYP1A1/2) inhibited the N-desisopropylation of R- and S-propranolol by human liver microsomes by 20 and 40%, respectively, while quinidine (a selective inhibitor of CYP2D6) abolished the 4-hydroxylation of both propranolol enantiomers almost completely. In contrast, sulphaphenazole (CYP2C8/9 inhibitor), S-mephenytoin (CYP2C19 inhibitor), troleandomycin (CYP3A3/4 inhibitor) and diethyldithiocarbamate (CYP2E1 inhibitor) elicited only weak inhibitory effects on propranolol metabolism via the two measured metabolic pathways. 3. Significant (P < 0.01) correlations were observed between the microsomal N-desisopropylation of both propranolol enantiomers and that for the O-deethylation of phenacetin among the 11 different human liver microsome samples (r = 0.98 and 0.77 for R- and S-propranolol, respectively). A marginally significant (r = 0.60, P congruent to 0.05) correlation was also observed between N-desisopropylation of S-, but not of R-propranolol and the 4'-hydroxylation of S-mephenytoin. No significant correlations were observed between the N-desisopropylation of propranolol enantiomers and the 2-hydroxylation of desipramine, the hydroxylation of tolbutamide or the 6 beta-hydroxylation of testosterone. 4. Significant (P < 0.01) correlations were observed between the microsomal 4-hydroxylation of R- and S-propranolol and the 2-hydroxylation of desipramine (r = 0.85 and 0.98, respectively). A weak (r = 0.66), albeit significant (P < 0.05) correlation was observed between the 4-hydroxylation of R-, but not of S-propranolol and the hydroxylation of tolbutamide. No significant correlations were observed between the 4-hydroxylation of propranolol enantiomers and the oxidation of other substrates for CYP1A2, 2C19, and 3A3/4. 5. Recombinant human CYP1A2 and CYP2D6 exhibited comparable catalytic activity with respect to the N-desisopropylation of both propranolol enantiomers; only expressed CYP2D6 exhibited a marked catalytic activity with respect to the 4-hydroxylation of both propranolol enantiomers.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K Yoshimoto
- Department of Clinical Pharmacology, International Medical Center of Japan, Tokyo
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