1
|
Rasekh P, Kameli A, Khoradmehr A, Baghban N, Mohebbi G, Barmak A, Nabipour I, Azari H, Heidari Y, Daneshi A, Bargahi A, Khodabandeh Z, Zare S, Afshar A, Shirazi R, Almasi-Turk S, Tamadon A. Proliferative Effect of Aqueous Extract of Sea Cucumber ( Holothuria parva) Body Wall on Human Umbilical Cord Mesenchymal Stromal/Stem Cells. Mar Drugs 2023; 21:md21050267. [PMID: 37233461 DOI: 10.3390/md21050267] [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: 11/13/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 05/27/2023] Open
Abstract
Sea cucumber extracts and their bioactive compounds have the potential for stem cell proliferation induction and for their beneficial therapeutic properties. In this study, human umbilical cord mesenchymal stromal/stem cells (hUC-MSCs) were exposed to an aqueous extract of Holothuria parva body walls. Proliferative molecules were detected using gas chromatography-mass spectrometry (GC-MS) analysis in an aqueous extract of H. parva. The aqueous extract concentrations of 5, 10, 20, 40, and 80 µg/mL and 10 and 20 ng/mL of human epidermal growth factor (EGF) as positive controls were treated on hUC-MSCs. MTT, cell count, viability, and cell cycle assays were performed. Using Western blot analysis, the effects of extracts of H. parva and EGF on cell proliferation markers were detected. Computational modeling was done to detect effective proliferative compounds in the aqueous extract of H. parva. A MTT assay showed that the 10, 20, and 40 µg/mL aqueous extract of H. parva had a proliferative effect on hUC-MSCs. The cell count, which was treated with a 20 µg/mL concentration, increased faster and higher than the control group (p < 0.05). This concentration of the extract did not have a significant effect on hUC-MSCs' viability. The cell cycle assay of hUC-MSCs showed that the percentage of cells in the G2 stage of the extract was biologically higher than the control group. Expression of cyclin D1, cyclin D3, cyclin E, HIF-1α, and TERT was increased compared with the control group. Moreover, expression of p21 and PCNA decreased after treating hUC-MSCs with the extract. However, CDC-2/cdk-1 and ERK1/2 had almost the same expression as the control group. The expression of CDK-4 and CDK-6 decreased after treatment. Between the detected compounds, 1-methyl-4-(1-methyl phenyl)-benzene showed better affinity to CDK-4 and p21 than tetradecanoic acid. The H. parva aqueous extract showed proliferative potential on hUC-MSCs.
Collapse
Affiliation(s)
- Poorya Rasekh
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Ali Kameli
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Arezoo Khoradmehr
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Neda Baghban
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Gholamhossein Mohebbi
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Alireza Barmak
- Food Lab, Bushehr University of Medical Sciences, Bushehr 7518759577, Iran
| | - Iraj Nabipour
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Hossein Azari
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Yaser Heidari
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Adel Daneshi
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Afshar Bargahi
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Zahra Khodabandeh
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz 71348-14336, Iran
| | - Shahrokh Zare
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz 71348-14336, Iran
| | - Alireza Afshar
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Reza Shirazi
- Department of Anatomy, School of Medical Sciences, Medicine, UNSW Sydney, Sydney 3052, Australia
| | - Sahar Almasi-Turk
- Department of Anatomical Sciences, School of Medicine, Bushehr University of Medical Sciences, Bushehr 7514633196, Iran
| | - Amin Tamadon
- PerciaVista R&D Co., Shiraz 7167683745, Iran
- Department for Scientific Work, West Kazakhstan Marat Ospanov Medical University, Aktobe 030012, Kazakhstan
| |
Collapse
|
2
|
Cheng J, Zhen Y, Miksys S, Beyoğlu D, Krausz KW, Tyndale RF, Yu A, Idle JR, Gonzalez FJ. Potential role of CYP2D6 in the central nervous system. Xenobiotica 2013; 43:973-84. [PMID: 23614566 DOI: 10.3109/00498254.2013.791410] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
1. Cytochrome P450 2D6 (CYP2D6) is a pivotal enzyme responsible for a major drug oxidation polymorphism in human populations. Distribution of CYP2D6 in brain and its role in serotonin metabolism suggest that CYP2D6 may have a function in the central nervous system. 2. To establish an efficient and accurate platform for the study of CYP2D6 in vivo, a human CYP2D6 (Tg-2D6) model was generated by transgenesis in wild-type (WT) C57BL/6 mice using a P1 phage artificial chromosome clone containing the complete human CYP2D locus, including the CYP2D6 gene and 5'- and 3'-flanking sequences. 3. Human CYP2D6 was expressed not only in the liver but also in the brain. The abundance of serotonin and 5-hydroxyindoleacetic acid in brain of Tg-2D6 is higher than in WT mice, either basal levels or after harmaline induction. Metabolomics of brain homogenate and cerebrospinal fluid revealed a significant up-regulation of L-carnitine, acetyl-L-carnitine, pantothenic acid, 2'-deoxycytidine diphosphate (dCDP), anandamide, N-acetylglucosaminylamine and a down-regulation of stearoyl-L-carnitine in Tg-2D6 mice compared with WT mice. Anxiety tests indicate Tg-2D6 mice have a higher capability to adapt to anxiety. 4. Overall, these findings indicate that the Tg-2D6 mouse model may serve as a valuable in vivo tool to determine CYP2D6-involved neurophysiological metabolism and function.
Collapse
Affiliation(s)
- Jie Cheng
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda, MD , USA
| | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Cooke BR, Bligh SWA, Cybulski ZR, Ioannides C, Hall M. Debrisoquine metabolism and CYP2D expression in marmoset liver microsomes. Drug Metab Dispos 2011; 40:70-5. [PMID: 21976620 DOI: 10.1124/dmd.111.041566] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to define CYP2D enzymes in marmoset (Callithrix jacchus) liver microsomes, both at the activity level using debrisoquine as the model substrate and at the protein level using antibodies raised to human CYP2D6. Marmoset liver microsomes were incubated with [(14)C]debrisoquine, and the structure of the generated metabolites was determined using liquid chromatography-tandem mass spectrometry and NMR. Marmoset liver microsomes were very effective in hydroxylating debrisoquine at various positions. Although 4-hydroxydebrisoquine was formed, in contrast to rat and human it was only a minor metabolite. Debrisoquine was more extensively hydroxylated in the 7, 5, 6, and 8 positions. In addition to the monohydroxylated metabolites, a dihydroxy metabolite, namely 6,7-dihydroxydebrisoquine, was identified. Finally, metabolites that had undergone ring opening were also detected but were not investigated further. Antibodies to CYP2D6 immunoreacted with protein in marmoset and human but not rat hepatic microsomes. In conclusion, we demonstrate that marmoset liver microsomes are effective in hydroxylating debrisoquine at various positions and that they contain a protein that is immunorelated to human CYP2D6.
Collapse
Affiliation(s)
- Brian R Cooke
- Department of In Vitro Metabolism, Huntingdon Life Sciences Ltd., Woolley Road, Alconbury, Huntingdon, Cambridgeshire, PE28 4HS, UK
| | | | | | | | | |
Collapse
|
4
|
Haddad S, Poulin P, Funk C. Extrapolating In vitro Metabolic Interactions to Isolated Perfused Liver: Predictions of Metabolic Interactions between R-Bufuralol, Bunitrolol, and Debrisoquine. J Pharm Sci 2010; 99:4406-26. [DOI: 10.1002/jps.22136] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
5
|
Abstract
Xenobiotic metabolism, a ubiquitous natural response to foreign compounds, elicits initiating signals for many pathophysiological events. Currently, most widely used techniques for identifying xenobiotic metabolites and metabolic pathways are empirical and largely based on in vitro incubation assays and in vivo radiotracing experiments. Recent work in our lab has shown that LC-MS-based metabolomic techniques are useful tools for xenobiotic metabolism research since multivariate data analysis in metabolomics can significantly rationalize the processes of xenobiotic metabolite identification and metabolic pathway analysis. In this review, the technological elements of LC-MS-based metabolomics for constructing high-quality datasets and conducting comprehensive data analysis are examined. Four novel approaches of using LC-MS-based metabolomic techniques in xenobiotic metabolism research are proposed and illustrated by case studies and proof-of-concept experiments, and the perspective on their application is further discussed.
Collapse
Affiliation(s)
- Chi Chen
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
6
|
|
7
|
Zhen Y, Slanař O, Krausz KW, Chen C, Slavík J, McPhail KL, Zabriskie TM, Perlík F, Gonzalez FJ, Idle JR. 3,4-Dehydrodebrisoquine, a novel debrisoquine metabolite formed from 4-hydroxydebrisoquine that affects the CYP2D6 metabolic ratio. Drug Metab Dispos 2006; 34:1563-74. [PMID: 16782768 PMCID: PMC1553181 DOI: 10.1124/dmd.105.008920] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Considerable unexplained intersubject variability in the debrisoquine metabolic ratio (urinary debrisoquine/4-hydroxydebrisoquine) exists within individual CYP2D6 genotypes. We speculated that debrisoquine was converted to as yet undisclosed metabolites. Thirteen healthy young volunteers, nine CYP2D6*1 homozygotes [extensive metabolizers (EMs)] and four CYP2D6*4 homozygotes [poor metabolizers (PMs)] took 12.8 mg of debrisoquine hemisulfate by mouth and collected 0- to 8- and 8- to 24-h urines, which were analyzed by gas chromatography-mass spectrometry (GCMS) before and after treatment with beta-glucuronidase. Authentic 3,4-dehydrodebrisoquine was synthesized and characterized by GCMS, liquid chromatography-tandem mass spectrometry, and (1)H NMR. 3,4-Dehydrodebrisoquine is a novel metabolite of debrisoquine excreted variably in 0- to 24-h urine, both in EMs (3.1-27.6% of dose) and PMs (0-2.1% of dose). This metabolite is produced from 4-hydroxydebrisoquine in vitro by human and rat liver microsomes. A previously unstudied CYP2D6*1 homozygote was administered 10.2 mg of 4-hydroxydebrisoquine orally and also excreted 3,4-dehydrodebrisoquine. EMs excreted 6-hydroxydebrisoquine (0-4.8%) and 8-hydroxydebrisoquine (0-1.3%), but these phenolic metabolites were not detected in PM urine. Debrisoquine and 4-hydroxydebrisoquine glucuronides were excreted in a highly genotype-dependent manner. A microsomal activity that probably does not involve cytochrome P450 participates in the further metabolism of 4-hydroxydebrisoquine, which we speculate may also lead to the formation of 1- and 3-hydroxydebrisoquine and their ring-opened products. In conclusion, this study suggests that the traditional metabolic ratio is not a true measure of the debrisoquine 4-hydroxylation capacity of an individual and thus may, in part, explain the wide intragenotype variation in metabolic ratio.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jeffrey R. Idle
- Corresponding author: Professor Jeffrey R. Idle, ; Institute of Pharmacology, 1 Faculty of Medicine, Charles University, Albertov 4, 128 00 Prague 2, Czech Republic. Tel: +420 603 484 583; Fax: +420 220 912 140
| |
Collapse
|
8
|
Yu AM, Idle JR, Gonzalez FJ. Polymorphic cytochrome P450 2D6: humanized mouse model and endogenous substrates. Drug Metab Rev 2004; 36:243-77. [PMID: 15237854 DOI: 10.1081/dmr-120034000] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cytochrome P450 2D6 (CYP2D6) is the first well-characterized polymorphic phase I drug-metabolizing enzyme, and more than 80 allelic variants have been identified for the CYP2D6 gene, located on human chromosome 22q13.1. Human debrisoquine and sparteine metabolism is subdivided into two principal phenotypes--extensive metabolizer and poor metabolizer--that arise from variant CYP2D6 genotypes. It has been estimated that CYP2D6 is involved in the metabolism and disposition of more than 20% of prescribed drugs, and most of them act in the central nervous system or on the heart. These drug substrates are characterized as organic bases containing one nitrogen atom with a distance about 5, 7, or 10 A from the oxidation site. Aspartic acid 301 and glutamic acid 216 were determined as the key acidic residues for substrate-enzyme binding through electrostatic interactions. CYP2D6 transgenic mice, generated using a lambda phage clone containing the complete wild-type CYP2D6 gene, exhibits enhanced metabolism and disposition of debrisoquine. This transgenic mouse line and its wild-type control are models for human extensive metabolizers and poor metabolizers, respectively, and would have broad application in the study of CYP2D6 polymorphism in drug discovery and development, and in clinical practice toward individualized drug therapy. Endogenous 5-methoxyindole- thylamines derived from 5-hydroxytryptamine were identified as high-affinity substrates of CYP2D6 that catalyzes their O-demethylations with high enzymatic capacity and specificity. Thus, polymorphic CYP2D6 may play an important role in the interconversions of these psychoactive tryptamines, including a crucial step in a serotonin-melatonin cycle.
Collapse
Affiliation(s)
- Ai-Ming Yu
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
9
|
Daly AK. Development of analytical technology in pharmacogenetic research. Naunyn Schmiedebergs Arch Pharmacol 2003; 369:133-40. [PMID: 14513205 DOI: 10.1007/s00210-003-0794-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 07/28/2003] [Indexed: 12/15/2022]
Abstract
Methods used to determine phenotype and genotype for pharmacogenetic polymorphisms are discussed. Phenotyping is mainly applicable to polymorphisms affecting drug disposition rather than drug response and can involve either direct measurement of enzyme activity or administration of a probe drug followed by measurement of drug and/or metabolite levels. Genotyping is now more widely used than phenotyping and can be used to determine genotype for polymorphisms affecting either drug disposition (for example those in the cytochromes P450 or N-acetyltransferases) or drug response (for example those in drug receptors). Most genotyping for known polymorphisms involves use of the polymerase chain reaction and the wide variety of methods based on this technique that are now used for routine genotyping are discussed in detail. In addition, a range of methods that can be used to detect novel polymorphisms, thereby further increasing understanding of interindividual variability in drug disposition and response, is described.
Collapse
Affiliation(s)
- Ann K Daly
- Pharmacogenetics Group, School of Clinical and Laboratory Sciences, Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
| |
Collapse
|
10
|
Yu AM, Granvil CP, Haining RL, Krausz KW, Corchero J, Küpfer A, Idle JR, Gonzalez FJ. The relative contribution of monoamine oxidase and cytochrome p450 isozymes to the metabolic deamination of the trace amine tryptamine. J Pharmacol Exp Ther 2003; 304:539-46. [PMID: 12538805 DOI: 10.1124/jpet.102.043786] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tryptamine is a trace amine in mammalian central nervous system that interacts with the trace amine TA(2) receptor and is now thought to function as a neurotransmitter or neuromodulator. It had been reported that deamination of tryptamine to tryptophol was mediated by CYP2D6, a cytochrome P450 that is expressed in human brain, suggesting that tryptamine may be an endogenous substrate for this polymorphic enzyme. We were unable to confirm this report and have reinvestigated tryptamine metabolism in human liver microsomes (HLM) and in microsomes expressing recombinant human cytochrome P450 and monoamine oxidase (MAO) isozymes. Tryptamine was oxidized to indole-3-acetaldehyde by HLM and recombinant human MAO-A in the absence of NADPH, and indole-3-acetaldehyde was further reduced to tryptophol by aldehyde reductase in HLM in the presence of NADPH. Steady-state kinetic parameters were estimated for each reaction step by HLM and MAO-A. The CYP2D6 substrates bufuralol and debrisoquine showed strong inhibition of both tryptophol production from tryptamine in HLM and the formation of indole-3-acetaldehyde from tryptamine catalyzed by recombinant MAO-A. Anti-CYP2D6 monoclonal antibody did not inhibit these reactions. Pargyline, a nonselective MAO inhibitor, did not show cross inhibition to debrisoquine 4-hydroxylation and dextromethorphan O-demethylation by HLM and recombinant CYP2D6 enzyme. This is the first unequivocal report of the selective conversion of tryptamine to tryptophol by MAO-A. CYP2D6 does not contribute to this reaction.
Collapse
Affiliation(s)
- Ai-Ming Yu
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Granvil CP, Krausz KW, Gelboin HV, Idle JR, Gonzalez FJ. 4-Hydroxylation of debrisoquine by human CYP1A1 and its inhibition by quinidine and quinine. J Pharmacol Exp Ther 2002; 301:1025-32. [PMID: 12023534 DOI: 10.1124/jpet.301.3.1025] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A panel of 15 recombinant cytochromes P450 expressed in human B-lymphoblastoid cells was used to study debrisoquine 4-hydroxylation. Both CYP2D6 and CYP1A1 carried out the reaction. The apparent K(m) (micromolar) and V(max) (picomoles per minute per picomole of P450) for CYP2D6 were 12.1 and 18.2 and for CYP1A1 were 23.1 and 15.2, respectively. CYP1A1 debrisoquine 4-hydroxylase was inhibited by the CYP1A1 inhibitor alpha-naphthoflavone and the CYP1A1 substrate 7-ethoxyresorufin. Additionally and surprisingly, this reaction was also inhibited by quinidine and quinine, with respective IC(50) values of 1.38 +/- 0.10 and 3.31 +/- 0.14 microM, compared with those for CYP2D6 debrisoquine 4-hydroxylase of 0.018 +/- 0.05 and 3.75 +/- 2.07 microM, respectively. Anti-CYP1A1 monoclonal antibody (mAb) 1-7-1 abolished CYP1A1 debrisoquine hydroxylase and anti-CYP2D6 mAb 50-1-3 eradicated CYP2D6 debrisoquine 4-hydroxylase. Three further CYP2D6-specific reactions were tested: dextromethorphan O-demethylation, bufuralol 1'-hydroxylation, and sparteine dehydrogenation. The CYP2D6 specificity, judged by the CYP2D6/CYP1A1 activity ratios was 18.5, 7.0, 6.0, and 1.6 for dextromethorphan, bufuralol, sparteine, and debrisoquine, respectively. Thus, debrisoquine is not a specific CYP2D6 substrate and quinidine is not a specific CYP2D6 inhibitor. These findings have significant implications for the conduct of in vitro drug metabolism inhibition studies and underscore the fallacy of "specific chemical inhibitors" of a supergene family of enzymes that have overlapping substrate specificities. The use of highly specific mAbs in such studies is mandated. It is unclear as yet whether these findings have implications for the relationship between CYP2D6 genotype and in vivo debrisoquine 4-hydroxylase activity.
Collapse
Affiliation(s)
- Camille P Granvil
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 3E24, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
12
|
Corchero J, Granvil CP, Akiyama TE, Hayhurst GP, Pimprale S, Feigenbaum L, Idle JR, Gonzalez FJ. The CYP2D6 humanized mouse: effect of the human CYP2D6 transgene and HNF4alpha on the disposition of debrisoquine in the mouse. Mol Pharmacol 2001; 60:1260-7. [PMID: 11723233 DOI: 10.1124/mol.60.6.1260] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2D6 is a highly polymorphic human gene responsible for a large variability in the disposition of more than 100 drugs to which humans may be exposed. Animal models are inadequate for preclinical pharmacological evaluation of CYP2D6 substrates because of marked species differences in CYP2D isoforms. To overcome this issue, a transgenic mouse line expressing the human CYP2D6 gene was generated. The complete wild-type CYP2D6 gene, including its regulatory sequence, was microinjected into a fertilized FVB/N mouse egg, and the resultant offspring were genotyped by both polymerase chain reaction and Southern blotting. CYP2D6-specific protein expression was detected in the liver, intestine, and kidney from only the CYP2D6 humanized mice. Pharmacokinetic analysis revealed that debrisoquine (DEB) clearance was markedly higher (94.1 +/- 22.3 l/h/kg), and its half-life significantly reduced (6.9 +/- 1.6 h), in CYP2D6 humanized mice compared with wild-type animals (15.2 +/- 0.9 l/h/kg and 16.5 +/- 4.5 h, respectively). Mutations in hepatic nuclear factor 4alpha (HNF4alpha), a hepatic transcription factor known to regulate in vitro expression of the CYP2D6 gene, could affect the disposition of CYP2D6 drug substrates. To determine whether the HNF4alpha gene modulates in vivo pharmacokinetics of CYP2D6 substrates, a mouse line carrying both the CYP2D6 gene and the HNF4alpha conditional mutation was generated and phenotyped using DEB. After deletion of HNF4alpha, DEB 4-hydroxylase activity in CYP2D6 humanized mice decreased more than 50%. The data presented in this study show that only CYP2D6 humanized mice but not wild-type mice display significant DEB 4-hydroxylase activity and that HNF4alpha regulates CYP2D6 activity in vivo. The CYP2D6 humanized mice represent an attractive model for future preclinical studies on the pharmacology, toxicology, and physiology of CYP2D6-mediated metabolism.
Collapse
Affiliation(s)
- J Corchero
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Lightfoot T, Ellis SW, Mahling J, Ackland MJ, Blaney FE, Bijloo GJ, De Groot MJ, Vermeulen NP, Blackburn GM, Lennard MS, Tucker GT. Regioselective hydroxylation of debrisoquine by cytochrome P4502D6: implications for active site modelling. Xenobiotica 2000; 30:219-33. [PMID: 10752638 DOI: 10.1080/004982500237622] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
1. Debrisoquine, a prototypic probe substrate for human cytochrome P4502D6 (CYP2D6), is hydroxylated at the alicyclic C4-position by this enzyme. Phenolic metabolites of debrisoquine (5-, 6-, 7- and 8-hydroxydebrisoquine) have also been reported as in vivo metabolites, but the role of CYP2D6 in their formation is unclear. 2. As part of studies to develop a predictive model of the active site of CYP2D6 using pharmacophore and homology modelling techniques, it became important to determine the precise regioselective hydroxylation of debrisoquine by CYP2D6. 3. Data from studies with human liver microsomes and yeast microsomes containing cDNA-derived CYP2D6 demonstrated unequivocally that debrisoquine was hydroxylated by CYP2D6 at each aromatic site in the molecule, as well as at the alicyclic 4-position. The four phenolic metabolites amounted to > 60% of the total identified products and the pattern of regioselective hydroxylation (4-HD > 7-HD > 6-HD > 8-HD > 5-HD) was similar in both in vitro systems. 4. A pharmacophore model for CYP2D6 indicated that while the hydroxylation of debrisoquine at alternative positions could arise from the substrate adopting multiple binding orientations, the energy constraints for the aromatic hydroxylations were unfavourable. An alternative proposal involving essentially a single binding orientation and a mechanism of hydroxylation based on benzylic radical spin delocalization could satisfactorily rationalize all the hydroxylations of debrisoquine. 5. This latter proposal demonstrates the need to consider the mechanism of oxidation as well as the spatial orientation of the substrate in the development of a predictive model of the active site of CYP2D6.
Collapse
Affiliation(s)
- T Lightfoot
- University of Sheffield, Section of Molecular Pharmacology and Pharmacogenetics, Royal Hallamshire Hospital, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Hamelin BA, Turgeon J, Vallée F, Bélanger PM, Paquet F, LeBel M. The disposition of fluoxetine but not sertraline is altered in poor metabolizers of debrisoquin. Clin Pharmacol Ther 1996; 60:512-21. [PMID: 8941024 DOI: 10.1016/s0009-9236(96)90147-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Substrates and inhibitors of the cytochrome P450 isozyme CYP2D6 have overlapping structural characteristics. Two prototype serotonin uptake inhibitors, sertraline and fluoxetine, share these structural criteria and have been identified as potent inhibitors of CYP2D6 in vitro. The current study was undertaken to investigate whether genetically determined CYP2D6 activity alters the disposition of sertraline or fluoxetine or both. METHODS Single doses of sertraline (50 mg) and fluoxetine (20 mg) were administered successively to 20 young men with high (extensive metabolizers; n = 10) and low (poor metabolizers; n = 10) CYP2D6 activity. Blood and urine samples were collected for 5 to 7 half-lives and sertraline, desmethylsertraline, fluoxetine, and norfluoxetine were determined by GC and HPLC techniques. RESULTS Poor metabolizers had significantly greater fluoxetine peak plasma concentrations (Cmax; increases 57%), area under the concentration versus time curve (AUCzero-->infinity; increases 290%), and terminal elimination half-life (increases 216%) compared with extensive metabolizers. The total amount of fluoxetine excreted in the urine during 8 days was almost three times higher in poor metabolizers than in extensive metabolizers (719 versus 225 micrograms; p < 0.05), whereas the total amount of norfluoxetine excreted in urine of poor metabolizers was about half of that of extensive metabolizers (524 versus 1047 micrograms; p < 0.05). Norfluoxetine Cmax and AUCzero-->t were significantly smaller in poor metabolizers (decreases 55% and decreases 53%, respectively), and the partial metabolic clearance of fluoxetine into norfluoxetine was 10 times smaller in this group (4.3 +/- 1.9 versus 0.4 +/- 0.1 L/hr; p < 0.05). No significant differences between extensive and poor metabolizers were found for sertraline and desmethylsertraline pharmacokinetics. CONCLUSION These data indicate that poor metabolizers accumulate fluoxetine but not sertraline and that CYP2D6 plays an important role in the demethylation of fluoxetine but not of sertraline.
Collapse
Affiliation(s)
- B A Hamelin
- School of Pharmacy, Université Laval, Quebec Heart Institute, Laval Hospital, Sainte-Foy, Canada
| | | | | | | | | | | |
Collapse
|
15
|
Anthony LB, Boeve TJ, Hande KR. Cytochrome P-450IID6 phenotyping in cancer patients: debrisoquin and dextromethorphan as probes. Cancer Chemother Pharmacol 1995; 36:125-8. [PMID: 7767948 DOI: 10.1007/bf00689196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The usefulness of substituting dextromethorphan for debrisoquin as a probe for cytochrome P-450IID6 deficiency was investigated in 20 male cancer patients. Each patient was studied on two occasions. An oral dose of dextromethorphan (60 mg) was administered to 13 patients and are week later an oral dose of debrisoquin (10 mg) was administered to each patient. The order was reversed for the other 7 patients. An 8-h urine sample was collected after administration of each test drug and assayed for parent drug and metabolites. Five poor metabolizers (PMs) and 15 extensive metabolizers (EMs) of debrisoquin were tested. The debrisoquin metabolic ratio (DMR), calculated as [parent drug]/[metabolite], correlated with the metabolic ratio of dextromethorphan (R2 = 0.58, P = 0.0001). All PMs of debrisoquin (metabolic ratio > 12.0) were easily identified as being PMs of dextromethorphan (metabolic ratio > 0.30). Within the EM group, there was a significant correlation between the metabolic ratios of debrisoquin and dextromethorphan (R2 = 0.82, P < 0.0001). There was not as clear a correlation in the PM group (R2 = 0.32, P = 0.32). These findings suggest that dextromethorphan can be substituted for debrisoquin in establishing the debrisoquin phenotype in a patient population with metastatic cancer.
Collapse
Affiliation(s)
- L B Anthony
- Division of Medical Oncology, Vanderbilt Clinic, Nashville, TN 37232-5536, USA
| | | | | |
Collapse
|
16
|
Mitchell SC, Shah RR, Clements DG, Smith RL. Changes in debrisoquine hydroxylation capacity following liver surgery. Hum Exp Toxicol 1994; 13:537-41. [PMID: 7946508 DOI: 10.1177/096032719401300805] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Liver transplantation or the surgical construction of portacaval shunts may radically alter an individual's debrisoquine hydroxylation capacity. Good clinical management should encompass a full awareness of such changing needs and problems in patients who undergo hepatic surgery.
Collapse
Affiliation(s)
- S C Mitchell
- Department of Pharmacology and Toxicology, St. Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, London, UK
| | | | | | | |
Collapse
|
17
|
Ponz de Leon M. Genetic factors in lung cancer. Recent Results Cancer Res 1994; 136:146-61. [PMID: 7863093 DOI: 10.1007/978-3-642-85076-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M Ponz de Leon
- Università degli Studi di Modena, Istituto di Patologia Medica, Italy
| |
Collapse
|
18
|
Kiivet RA, Svensson JO, Bertilsson L, Sjöqvist F. Polymorphism of debrisoquine and mephenytoin hydroxylation among Estonians. PHARMACOLOGY & TOXICOLOGY 1993; 72:113-5. [PMID: 8474964 DOI: 10.1111/j.1600-0773.1993.tb00300.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Debrisoquine and S-mephenytoin hydroxylation polymorphisms were studied in 156 unrelated native Estonians. The hydroxylation phenotypes were assessed by coadministration of mephenytoin with debrisoquine or dextromethorphan. The frequency of the poor metaboliser phenotype of debrisoquine/dextromethorphan was 4.5% (95% confidence interval 1.2-7.8%), and that of mephenytoin was 3.9% (95% confidence interval 0.9-6.9%) among Estonians, which is very similar to what has been reported in other Caucasian populations.
Collapse
Affiliation(s)
- R A Kiivet
- Department of Pharmacology, Tartu University, Estonia
| | | | | | | |
Collapse
|
19
|
Ho JW, Moody DE. Gas chromatography/mass spectrometry assays for the determination of debrisoquine and sparteine metabolites in microsomal fractions of rat liver. Anal Biochem 1992; 203:348-51. [PMID: 1416032 DOI: 10.1016/0003-2697(92)90323-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Debrisoquine and sparteine are prototype substrates of a genetic deficiency in cytochrome P450-dependent drug metabolism. Sensitive assays of in vitro oxidation of sparteine and debrisoquine are required for evaluation of this polymorphism. The activities were measured by quantitative analysis of 2-dehydrosparteine and 4-hydroxydebrisoquine production, respectively, using capillary column gas chromatography coupled with mass selective ion detection. With a single extraction, separation of parent drug, metabolite, and a suitable internal standard was readily achievable. Time-dependent production of both metabolites could be detected from as little as 40 micrograms of microsomal protein. Both activities showed a maximal activity with a 240-min incubation period. The ability to simultaneously quantify the parent drug and its metabolite suggests it would also be useful for evaluation of in vivo metabolism.
Collapse
Affiliation(s)
- J W Ho
- Department of Pharmacology and Toxicology, University of Utah College of Pharmacy, Salt Lake City 84108
| | | |
Collapse
|
20
|
Daumas L, Sabot JF, Vermeulen E, Clapot P, Allegre F, Pinatel H, Boucherat M, Francois B. Determination of debrisoquine and metabolites in human urine by gas chromatography-mass spectrometry. JOURNAL OF CHROMATOGRAPHY 1991; 570:89-97. [PMID: 1797839 DOI: 10.1016/0378-4347(91)80203-o] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A gas chromatographic-mass spectrometric analysis has been developed for the determination of debrisoquine and its metabolites in the urine of healthy individuals (controls) and patients with chronic renal failure. The sensitive and specific assay comprises selected-ion monitoring of the drug and the metabolites 4-hydroxydebrisoquine and 8-hydroxydebrisoquine using guanoxan as the internal standard. The limit of detection is ca. 0.2 microgram/ml. The clinical study shows that the healthy individuals and patients with chronic renal failure can be divided in two groups of extensive metabolizers and poor metabolizers, respectively. The extensive metabolizers excreted large amounts of 4-hydroxydebrisoquine and minor amounts of 8-hydroxydebrisoquine. The poor metabolizers excreted small amounts of 4-hydroxy metabolite, and no 8-hydroxydebrisoquine was detected in the urine.
Collapse
Affiliation(s)
- L Daumas
- Laboratoire de Chimie Analytique II, Faculté de Pharmacie, Lyon, France
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Veronese ME, McLean S. Debrisoquine oxidation polymorphism in a Tasmanian population. Eur J Clin Pharmacol 1991; 40:529-32. [PMID: 1884730 DOI: 10.1007/bf00315235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The debrisoquine hydroxylation phenotype was studied in 152 unselected healthy Tasmanian subjects, who were mostly Caucasians of British ancestry. Following a 10 mg oral dose of debrisoquine (D), the ratio of D/4-hydroxydebrisoquine excreted in 8-h urine (metabolic ratio, MR) was determined. MR values were bimodally distributed. Thirteen subjects (8.6%) had MR values from 13.8 to 93.3 and were considered to be poor metabolisers of D, while the others were extensive metabolisers with MR values of 0.04 to 5.4. The D hydroxylation phenotype was not associated with sex. These findings confirm the constancy of D polymorphism in a Caucasian population even after migration to another country.
Collapse
Affiliation(s)
- M E Veronese
- School of Pharmacy, University of Tasmania, Hobart, Australia
| | | |
Collapse
|
22
|
Bouget J, Bousser J, Pats B, Ramee MP, Chevet D, Rifle G, Giudicelli CP, Thomas R. Acute renal failure following collective intoxication by Cortinarius orellanus. Intensive Care Med 1990; 16:506-10. [PMID: 2286731 DOI: 10.1007/bf01709401] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Twenty-six young men with no previous medical history all ingested mushroom soup, exclusively made with Cortinarius orellanus. They were hospitalized 10-12 days after the incident. On admission, 12 patients presented with acute tubulointerstitial nephritis with acute renal failure; 8 required haemodialysis. In addition to symptomatic treatment, 9 patients were given corticosteroids. In this group of 12 patients, 8 recovered rapidly, and the other 4 suffered from chronic renal failure for several months. In the other group of 14 patients, initial leukocyturia was observed in 12 cases, although renal function remained normal during a one-year follow-up. Hepatic acetylation and hydroxylation tests performed after 6 months in 22 patients did not provide any explanation for the strong individual sensitivity to the renal toxicity of this fungus.
Collapse
Affiliation(s)
- J Bouget
- Casualty and Medical Emergency Unit, Hôpital Pontchaillou, Rennes, France
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Affiliation(s)
- M R Law
- Department of Environmental and Preventive Medicine, Medical College of St Bartholomew's Hospital, London, UK
| |
Collapse
|
24
|
Affiliation(s)
- M R Law
- Department of Environmental and Preventive Medicine, St Bartholomew's Hospital Medical College, Charterhouse Square, London, UK
| | | | | |
Collapse
|
25
|
Watson RG, Olomu A, Clements D, Waring RH, Mitchell S, Elias E. A proposed mechanism for chlorpromazine jaundice--defective hepatic sulphoxidation combined with rapid hydroxylation. J Hepatol 1988; 7:72-8. [PMID: 3183354 DOI: 10.1016/s0168-8278(88)80508-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
On the basis of previous experimental studies we postulated that individuals who were phenotypically good hydroxylators but poor sulphoxidisers would be susceptible to chlorpromazine jaundice. Sulphoxidation capacity was assessed in 12 subjects with a history of chlorpromazine jaundice, using S-carboxymethyl-L-cysteine as an in vivo probe. Following an oral dose of 750 mg, unchanged compound and sulphoxide metabolites were measured in urine. All 12 subjects (100%) were shown to be poor sulphoxidisers compared to 22% of normal controls (P less than 0.001) and 23.8% of liver disease controls (P less than 0.001). No subjects with a history of chlorpromazine jaundice had an impaired hydroxylation capacity as assessed by recovery of 4-hydroxydebrisoquine in urine following oral debrisoquine. The results support the hypothesis and demonstrate an inherent metabolic basis of susceptibility to chlorpromazine jaundice.
Collapse
Affiliation(s)
- R G Watson
- Queen Elizabeth Hospital, Birmingham, Edgbaston, U.K
| | | | | | | | | | | |
Collapse
|
26
|
Eichelbaum M, Bertilsson L, Küpfer A, Steiner E, Meese CO. Enantioselectivity of 4-hydroxylation in extensive and poor metabolizers of debrisoquine. Br J Clin Pharmacol 1988; 25:505-8. [PMID: 3382592 PMCID: PMC1387813 DOI: 10.1111/j.1365-2125.1988.tb03335.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Debrisoquine (DQ) has no chiral centre, but hydroxylation in position 4 leads to formation of an asymmetric carbon centre with two possible enantiomers, their absolute configuration being R(-) and S(+)-4-hydroxydebrisoquine (4-OHDQ). Since the absolute stereochemistry of the 4-hydroxylation of DQ in man is unknown, the enantioselectivity of this process was studied in panels of extensive (EM) and poor metabolizers (PM) of DQ. In EM subjects 4-hydroxylation of DQ leads almost exclusively to the formation of S(+)-4-OHDQ. In contrast, PM subjects were not only characterized by a decreased total 4-OHDQ formation but also a marked loss of enantioselectivity in product formation. Between 5 to 36% of total 4-OHDQ was excreted as R(-)-4-OHDQ.
Collapse
Affiliation(s)
- M Eichelbaum
- Dr Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, FRG
| | | | | | | | | |
Collapse
|
27
|
Meese CO, Fischer C, Eichelbaum M. Stereoselectivity of the 4-hydroxylation of debrisoquine in man, detected by gas chromatography/mass spectrometry. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1988; 15:63-6. [PMID: 3349209 DOI: 10.1002/bms.1200150202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A stable isotope assay for the quantification of debrisoquine (1) and its major urinary metabolite 4-hydroxydebrisoquine (2) is described. The method consists of extractive derivatization of 1 and 2 by use of 1,3-diketones, chiral derivatization of the 4-hydroxy group of 2, and gas chromatography/negative ion chemical ionization mass spectrometry in the presence of deuterated analogues of 1 and 2. In comparison with synthetic R-(-)-2 and S-(+)-2 it is shown that in vivo benzylic 4-hydroxylation of 1 is highly stereoselective, leading predominantly to S-(+)-4-hydroxydebrisoquine (enantiomeric excess greater than or equal to 90%).
Collapse
Affiliation(s)
- C O Meese
- Dr Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, FRG
| | | | | |
Collapse
|
28
|
Duche JC, Barre J, Tillement JP. Rapid liquid chromatographic determination of debrisoquine and its hydroxy metabolite in human urine to define hydroxylation phenotypes. JOURNAL OF CHROMATOGRAPHY 1987; 423:340-3. [PMID: 3443670 DOI: 10.1016/0378-4347(87)80361-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- J C Duche
- Laboratoire Hospitalo-Universitaire de Pharmacologie, Hôpital Intercommunal, Créteil, France
| | | | | |
Collapse
|
29
|
Meese CO, Thalheimer P, Eichelbaum M. High-performance liquid chromatographic method for the analysis of debrisoquine and its S-(+)- and R-(-)-hydroxy metabolites in urine. JOURNAL OF CHROMATOGRAPHY 1987; 423:344-50. [PMID: 3443671 DOI: 10.1016/0378-4347(87)80362-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- C O Meese
- Dr. Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, F.R.G
| | | | | |
Collapse
|
30
|
Snatzke G, Meese CO. Absolute Configuration of 1,2,3,4-Tetrahydro-4-hydroxyisoquinolines. ACTA ACUST UNITED AC 1987. [DOI: 10.1002/jlac.198719870115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
31
|
|
32
|
Baer AN, McAllister CB, Wilkinson GR, Woosley RL, Pincus T. Altered distribution of debrisoquine oxidation phenotypes in patients with systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 1986; 29:843-50. [PMID: 3741500 DOI: 10.1002/art.1780290705] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Oxidative metabolism in patients with systemic lupus erythematosus (SLE) was studied using the antihypertensive drug, debrisoquine. The metabolism of this drug to its principal metabolite, 4-hydroxydebrisoquine, is catalyzed by a discrete isozyme of cytochrome P-450. The extent of this reaction exhibits genetic polymorphism, with 2 phenotypes, "poor metabolizers" and "extensive metabolizers," discernible in the normal population. We observed the poor metabolizer debrisoquine phenotype in 9 of 42 patients with idiopathic SLE (21%), in contrast with 12 of 147 healthy volunteers (8%), which is a significant difference in frequency (P less than 0.04). These data provide further evidence for altered oxidative metabolism in SLE and support the concept that genetic differences in oxidative metabolism of endogenous compounds, such as sex steroid hormones, or of xenobiotics might influence susceptibility to SLE.
Collapse
|
33
|
McAllister CB, Wolfenden HT, Aslanian WS, Woosley RL, Wilkinson GR. Oxidative metabolism of encainide: polymorphism, pharmacokinetics and clinical considerations. Xenobiotica 1986; 16:483-90. [PMID: 3090789 DOI: 10.3109/00498258609050253] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The 8-h urinary metabolic profiles of encainide and its oxidized metabolites, O-desmethyl- (ODE), 3-methoxy-O-desmethyl- (MODE), N-desmethyl- (NDE) and N, O-didesmethyl- (DDE) encainide were studied in a group of 112 normal Caucasians. Nine of these subjects (8%) were defective in their ability to 4-hydroxylate debrisoquine. The cumulative frequency distribution of the 8-h recovery ratio of encainide/ODE indicated two distinct populations in complete concordance with the debrisoquine phenotyping. The subjects with an 'extensive metabolizer' (EM) phenotype had a ratio from 0.003 to 0.9 whereas the PM group had values from 7.4 to 48. In addition, no MODE was detected in the urine from 'poor metabolizers' (PM). The oxidative metabolism of encainide, specifically the O-demethylation pathway, is, therefore, polymorphically distributed and controlled by the same genetic factor(s) that determine the 4-hydroxylation of debrisoquine. In EM subjects, ODE and MODE are the major metabolites in plasma and their concentrations are much greater than those of unchanged drug. As ODE is a more potent antiarrhythmic agent than encainide and MODE is at least equipotent, these metabolites significantly contribute to the overall antiarrhythmic effect in EM patients. The low plasma concentrations of ODE and MODE in PM subjects would be expected to result in inefficacious therapy when usual doses of encainide are administered. However, in such individuals, chronic oral therapy results in accumulation of unmetabolized encainide to far higher levels than in EM subjects. As encainide itself has intrinsic antiarrhythmic activity at these concentrations, this generally results in the desired clinical response. Despite pronounced interphenotypic differences in encainide's disposition and pharmacokinetics, the polymorphic oxidative metabolism appears to have limited consequences for the drug's clinical efficacy.
Collapse
|
34
|
Ritchie JC, Crothers MJ, Shah RR, Idle JR, Smith RL. The metabolism of debrisoquine in man: (1) regioselectivity of hydroxylation and (2) aberrant oxidative metabolism in two sibling patients with carbimazole-induced agranulocytosis. Xenobiotica 1986; 16:503-9. [PMID: 3739370 DOI: 10.3109/00498258609050255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The regioselectivity of the metabolic hydroxylation of debrisoquine has been determined in 43 healthy British white volunteers and the priority was found to be in the order 4 greater than 7 greater than 6 greater than 5 greater than 8. The order of preference for hydroxylation position was independent of debrisoquine 4-hydroxylation phenotype. The extent of total aromatic hydroxylation varied widely between individuals and was largely independent of the extent of 4-hydroxylation, and thus of the influence of the DH/DL locus. Two sisters and their blood relations all excreted comparatively large amounts of the phenolic metabolites in their urine, indicating some genetic basis for the control of aromatic oxidation of debrisoquine in man. These same two sisters had previously developed agranulocytosis in association with carbimazole therapy.
Collapse
|
35
|
Westwood BE, Harman PJ, Mashford ML. Liquid chromatographic assay for debrisoquine and 4-hydroxydebrisoquine in urine. JOURNAL OF CHROMATOGRAPHY 1986; 374:200-3. [PMID: 3949930 DOI: 10.1016/s0378-4347(00)83272-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
36
|
Barbeau A, Cloutier T, Roy M, Plasse L, Paris S, Poirier J. Ecogenetics of Parkinson's disease: 4-hydroxylation of debrisoquine. Lancet 1985; 2:1213-6. [PMID: 2866293 DOI: 10.1016/s0140-6736(85)90743-3] [Citation(s) in RCA: 183] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is postulated that Parkinson's disease is the result of environmental factors acting on genetically susceptible individuals against a background of normal ageing. Many potentially neurotoxic xenobiotics are detoxified by hepatic cytochrome P450. The function of one such system was studied in forty patients with Parkinson's disease and forty normal control subjects. Significantly more parkinsonian than control subjects had partially or totally defective 4-hydroxylation of debrisoquine. Poor metabolisers of debrisoquine tended to have had earlier onset of disease.
Collapse
|
37
|
Ahnoff M, Ervik M, Lagerström PO, Persson BA, Vessman J. Drug level monitoring: cardiovascular drugs. JOURNAL OF CHROMATOGRAPHY 1985; 340:73-138. [PMID: 2862159 DOI: 10.1016/0378-4347(85)80195-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Methods for the determination of cardiovascular drugs in blood and plasma are critically reviewed with emphasis on gas and liquid chromatographic techniques. The importance of the various procedures is discussed, in particular sample work-up where the conditions for isolation and derivatization of the compounds are decisive for the accuracy and precision of the methods. Compared with other assay techniques chromatographic methods are generally to be preferred owing to their better selectivity. In the review the following groups are discussed: digitalis glycosides, antiarrhythmic agents, beta-adrenoceptor antagonists, vasodilating agents, antihypertensive compounds, and diuretics.
Collapse
|
38
|
Haley CS, Waring RH, Mitchell SC, Shah RR, Idle JR, Smith RL. Lack of congruence of S-carboxymethyl-L-cysteine sulphoxidation and debrisoquine 4-hydroxylation in a Caucasian population. Xenobiotica 1985; 15:445-50. [PMID: 4036168 DOI: 10.3109/00498258509045015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
One-hundred-and-twenty volunteers and three families were investigated for possible association between the sulphoxidation of S-carboxymethyl-L-cysteine and the debrisoquine hydroxylation polymorphism. The observed individual variations in these two metabolic reactions were shown not to be concordant (rs = 0.068) and any heritable factors controlling the major aspects of these phenomena do not co-segregate.
Collapse
|
39
|
Abstract
PCP is metabolized extensively in the body via a variety of metabolic routes. Biotransformation is a major mechanism of PCP elimination in humans and termination of PCP action in mice. In general, PCP metabolites are less active pharmacologically than PCP itself. Primary metabolism involves hydroxylation of the alicyclic rings at several carbon atoms by cytochrome P-450-mediated monooxygenase. Hydroxylation of the aromatic ring seems to be less likely and has not been conclusively demonstrated. Hydroxylation of PCP at carbon 2 of the piperidine ring to form the unstable carbinolamine leads to formation of a series of polar, open-ring compounds. Monohydroxylated metabolites are conjugated with glucuronic or sulfuric acid, or are further hydroxylated to dihydroxy derivatives that can also be subject to conjugation. Formation of highly reactive electrophilic metabolites of PCP have been demonstrated in vitro in microsomal preparations. Covalent modification of tissue macromolecules by reactive intermediates can be responsible for suicide inactivation of cytochrome P-450 and can possibly mediate some long-term toxic effects of PCP. PCP inhaled by cigarette smoking is metabolized via similar routes. About 50% of the PCP in cigarette smoke is converted to PC, a major product of thermal degradation of PCP. PC and its hydroxylated and conjugated metabolites appear to contribute little to the pharmacology or acute toxicity of PCP.
Collapse
|
40
|
Ayesh R, Idle JR, Ritchie JC, Crothers MJ, Hetzel MR. Metabolic oxidation phenotypes as markers for susceptibility to lung cancer. Nature 1984; 312:169-70. [PMID: 6504125 DOI: 10.1038/312169a0] [Citation(s) in RCA: 288] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
That bronchial carcinoma is not an inevitable consequence of cigarette smoking has stimulated the search for host factors that might influence the susceptibility of the individual smoker. One plausible host factor would be a polymorphic gene controlling the metabolic oxidative activation of chemical carcinogens, giving rise to wide inter-subject variation in the generation of cancer-inducing and/or promoting species. Recently, three genetic polymorphisms of human metabolic oxidation have been demonstrated (as characterized by debrisoquine, mephenytoin and carbocysteine), with the metabolism of several substrates exhibiting the phenomenon. Debrisoquine 4-hydroxylation segregates into two human phenotypes, each comprising characteristic metabolic capability. We report here the frequency of debrisoquine 4-hydroxylation phenotypes in age-, sex- and smoking history-matched bronchial carcinoma and control patients. Cancer patients showed a preponderance of probable homozygous dominant extensive metabolizers (78.8%) with few recessive poor metabolizers (1.6%) compared with smoking controls (27.8% and 9.0% respectively). We conclude that the gene controlling debrisoquine 4-hydroxylation may be a host genetic determinant of susceptibility to lung cancer in smokers and that it represents a marker to assist in assessing individual risk.
Collapse
|
41
|
Lanthier PL, Reshef R, Shah RR, Oates NS, Smith RL, Morgan MY. Oxidation phenotyping in alcoholics with liver disease of varying severity. Alcohol Clin Exp Res 1984; 8:435-41. [PMID: 6391252 DOI: 10.1111/j.1530-0277.1984.tb05697.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The propensity to develop alcoholic cirrhosis is probably, at least in part, genetically determined. A striking similarity exists histologically between perhexiline and alcohol-related hepatitis and both are potentially precirrhotic lesions. Liver damage due to perhexiline is associated with impaired drug oxidation capacity which is genetically determined and tested by use of debrisoquine. Oxidation phenotyping might be used to predict susceptibility to perhexiline liver damage; it might also predict the potential to develop alcoholic cirrhosis. Oxidation phenotyping was therefore undertaken, using debrisoquine in 100 alcoholic patients, 30 of whom had only fatty liver despite prolonged alcohol abuse, while the remaining 70 had alcoholic hepatitis and/or cirrhosis. One hundred patients with nonalcoholic chronic liver disease served as controls. The number of patients with severely impaired drug oxidation capacity (poor metabolizer phenotype) was similar in the alcoholic group (8%) and the nonalcoholic control group (7%). In particular, the incidence of the poor metabolizer phenotype was similar in alcoholics with severe liver disease (10%) and in those with only fatty change (3%). There appears to be no association between the susceptibility to develop alcoholic cirrhosis and drug oxidizing capacity.
Collapse
|
42
|
Sloan TP, Lancaster R, Shah RR, Idle JR, Smith RL. Genetically determined oxidation capacity and the disposition of debrisoquine. Br J Clin Pharmacol 1983; 15:443-50. [PMID: 6849780 PMCID: PMC1427798 DOI: 10.1111/j.1365-2125.1983.tb01528.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
1 The disposition in urine of debrisoquine and its hydroxylated metabolites has been studied in subjects of the 'extensive metabolizer' (EM; n = 5) and 'poor metabolizer' (PM; n = 5) phenotypes. The 4-hydroxylation of debrisoquine by PM subjects following a 10 mg oral dose was capacity-limited and displayed significant dose-dependency over a range of 1-20 mg. In contrast, the EM subjects' ability to perform this metabolic oxidation did not deviate from first-order kinetics over a dose range of 10-40 mg. 2 The disposition of debrisoquine in plasma following a 10 mg oral dose has been studied in EM (n = 4) and PM (n = 3) subjects. Whilst PM subjects displayed significantly higher plasma levels of debrisoquine at all time points following 1 h post-dosing, and higher values for areas under the plasma concentration-time curve (EM: 105.6 +/- 7.0 ng ml-1 h; PM: 371.4 +/- 22.4 ng ml-1 h, 2P less than 0.0001), neither debrisoquine plasma half-life (EM: 3.0 +/- 0.5 h; PM: 3.3 +/- 0.4 h) nor renal clearance of the drug (EM: 152.8 +/- 30.3 ml min-1; PM: 137 +/- 4.5 ml min-1) displayed significant inter-phenotype differences. 3 The results of these investigations show that the phenotyping of individuals for debrisoquine oxidation status by means of a 'metabolic ratio' derived from a single 0-8 h urine sample has a sound kinetic basis. The kinetic differences between the two phenotypes would strongly suggest that the metabolic defect manifested in PM subjects is one of pre-systemic elimination capacity.
Collapse
|
43
|
|
44
|
Küpfer A, Al-Dabbagh SG, Ritchie JC, Idle JR, Smith RL. Spectral binding studies of the polymorphically metabolized drugs debrisoquine, sparteine and phenformin by cytochrome P-450 of normal and hydroxylation deficient rat strains. Biochem Pharmacol 1982; 31:3193-9. [PMID: 7150348 DOI: 10.1016/0006-2952(82)90549-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mechanisms of polymorphic drug hydroxylation of debrisoquine, sparteine and related drugs in vivo have been investigated using Cyt P-450 preparations of inbred rat strains as an in vitro model of the poor and extensive metabolizer phenotypes found in various rat strains and in man. Optical difference spectroscopy with debrisoquine, sparteine, phenformin and three other drugs (selected test compounds with proven or suspected hydroxylation polymorphisms in man) exhibited Type 1 binding in normal Sprague-Dawley, Fischer and Lewis Cyt P-450, whereas no Type I drug binding was found in the hydroxylation deficient DA rat liver Cyt P-450. Cyt P-450 content and Type II drug binding of metiamide was the same in normal and hydroxylation deficient rat liver microsomes. The pronounced Type I drug binding in extensive hydroxylation Cyt P-450 and the defective Type I binding in DA Cyt P-450 in vitro, therefore, closely parallels the polymorphic hydroxylation pattern of these test drugs found in the four rat strains studied in vivo. Consequently, missing binding properties of Cyt P-450 or of its micro-environment might represent the enzymatic defect underlying the genetically determined hydroxylation deficiency of polymorphically metabolized drugs in the poor metabolizer phenotype in the DA rat and, by inference, in man.
Collapse
|
45
|
Kahn GC, Boobis AR, Murray S, Brodie MJ, Davies DS. Assay and characterisation of debrisoquine 4-hydroxylase activity of microsomal fractions of human liver. Br J Clin Pharmacol 1982; 13:637-45. [PMID: 7082530 PMCID: PMC1402066 DOI: 10.1111/j.1365-2125.1982.tb01430.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
1 A method for the assay of debrisoquine 4-hydroxylase activity in vitro by microsomal fractions of human liver is described. The assay utilises gas chromatography-mass spectrometry with d9-4-hydroxydebrisoquine as internal standard. 2 The limit of detection of 4-hydroxydebrisoquine was 2 ng ml -1 and the coefficient of variation was 4.4%. 3 Debrisoquine 4-hydroxylase activity was linear with protein to concentrations above 2.1 mg ml -1 and with incubation times of at least 15 min. 4 Debrisoquine 4-hydroxylase is a microsomal enzyme with a requirement for NADPH. Activity was inhibited by carbon monoxide. It is concluded that the activity is catalysed by cytochrome P-450. 5 In three samples of human liver the mean value for Vmax of debrisoquine 4-hydroxylase activity was 69.9 +/- 14.3 pmol mg -1 min -1 and for Km it was 130 +/- 24 microM. 6 The only variable from smoking status, alcohol ingestion, sex of the patients, source of liver sample and presence of liver disease that had a significant effect on 4-hydroxylation of debrisoquine was the presence of liver disease. This was associated with a decrease in enzyme activity.
Collapse
|
46
|
|
47
|
Oates NS, Shah RR, Idle JR, Smith RL. Phenformin-induced lacticacidosis associated with impaired debrisoquine hydroxylation. Lancet 1981; 1:837-8. [PMID: 6111700 DOI: 10.1016/s0140-6736(81)92711-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
48
|
|
49
|
Al-Dabbagh SG, Idle JR, Smith RL. Animal modelling of human polymorphic drug oxidation--the metabolism of debrisoquine and phenacetin in rat inbred strains. J Pharm Pharmacol 1981; 33:161-4. [PMID: 6116757 DOI: 10.1111/j.2042-7158.1981.tb13740.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The metabolism of debrisoquine (5 mg kg-1 orally) was investigated in females of 7 strains of rat. Two major metabolic pathways, those of 4- and 6-hydroxylation were found to be polymorphic. The DA strain eliminated in urine only 7-10% of the dose as 4-hydroxy-debrisoquine together with 31-55% debrisoquine while the corresponding values for the Lewis strain were 44-55% and 11-17% respectively. Accordingly, DA and Lewis rats were proposed as models for the human PM (poor metabolizer) and EM (extensive metabolizer) drug oxidation phenotypes. To further test this model, DA and Lewis rats were given phenacetin (200 mg kg-1 orally). This underwent O-de-ethylation to paracetamol (52-55%) and aromatic 2-hydroxylation (7-8%) in Lewis rats. The corresponding findings in DA rats were 35-40% O-de-ethylation and 12-13% 2-hydroxylation. It is suggested that, with respect to both debrisoquine and phenacetin, Lewis and DA inbred rat strains afford a model of oxidative drug metabolism for the human EM and PM phenotypes respectively.
Collapse
|
50
|
Chapman PH, Rawlins MD, Shuster S, Idle JR, Ritchie JC, Smith RL. Polymorphic 4-hydroxylation of debrisoquine in chronic discoid psoriasis. Eur J Clin Pharmacol 1981; 21:257-8. [PMID: 6895622 DOI: 10.1007/bf00627929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|