title: Involvement of UDP-glucuronosyltransferases UGT1A9 and UGT2B7 in ethanol glucuronidation, and interactions with common drugs of abuse.
abstract: Ethyl glucuronide (EtG) determination is increasingly used in clinical and forensic toxicology to document ethanol consumption. The enzymes involved in EtG production, as well as potential interactions with common drugs of abuse, have not been extensively studied. Activities of human liver (HLM), kidney (HKM), and intestinal (HIM) microsomes, as well as of 12 major human recombinant UDP-glucuronosyltransferases (UGTs), toward ethanol (50 and 500 mM) were evaluated in vitro using liquid chromatography-tandem mass spectrometry. Enzyme kinetic parameters were determined for pooled microsomes and recombinant UGTs with significant activity. Individual contributions of UGTs were estimated using the relative activity factor approach, proposed for scaling activities obtained with cDNA-expressed enzymes to HLM. Interaction of morphine, codeine, lorazepam, oxazepam, nicotine, cotinine, cannabinol, and cannabidiol (5, 10, 15 mg/l) with ethanol (1.15, 4.6, 11.5 g/l; i.e., 25, 100, 250 mM) glucuronidation was assessed using pooled HLM. Ethanol glucuronidation intrinsic clearance (Cl(int)) was 4 and 12.7 times higher for HLM than for HKM and HIM, respectively. All recombinant UGTs, except UGT1A1, 1A6, and 1A10, produced EtG in detectable amounts. UGT1A9 and 2B7 were the most active enzymes, each accounting for 17 and 33% of HLM Cl(int), respectively. Only cannabinol and cannabidiol significantly affected ethanol glucuronidation. Cannabinol increased ethanol glucuronidation in a concentration-dependent manner, whereas cannabidiol significantly inhibited EtG formation in a noncompetitive manner (IC(50) = 1.17 mg/l; inhibition constant (K(i)) = 3.1 mg/l). UGT1A9 and 2B7 are the main enzymes involved in ethanol glucuronidation. In addition, our results suggest that cannabinol and cannabidiol could significantly alter ethanol glucuronidation.
authors.affiliation: EA4483, Faculty of Medicine, Université Lille-Nord de France, Lille, France.
authors.forename: Alaa
authors.initials: A
authors.lastname: Al Saabi
authors.forename: Delphine
authors.initials: D
authors.lastname: Allorge
authors.forename: François-Ludovic
authors.initials: FL
authors.lastname: Sauvage
authors.forename: Gilles
authors.initials: G
authors.lastname: Tournel
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Gaulier
authors.forename: Pierre
authors.initials: P
authors.lastname: Marquet
authors.forename: Nicolas
authors.initials: N
authors.lastname: Picard
mesh_terms: D001711:Biotransformation; D002185:Cannabidiol / Q000494:pharmacology; D002187:Cannabinol / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000378:metabolism*; D015725:Fluconazole / Q000494:pharmacology; D005965:Glucuronates / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D013287:Illicit Drugs / Q000494:pharmacology*; D007422:Intestines / Q000201:enzymology; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology; D009544:Niflumic Acid / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D053719:Tandem Mass Spectrometry; D000090264:UDP-Glucuronosyltransferase 1A9
chemical_list: D004791:Enzyme Inhibitors; D005965:Glucuronates; D013287:Illicit Drugs; D011994:Recombinant Proteins; C000715591:UGT1A9 protein, human; C093924:ethyl glucuronide; D002185:Cannabidiol; D000431:Ethanol; D009544:Niflumic Acid; D002187:Cannabinol; D015725:Fluconazole; C491474:UGT2B7 protein, human; D014453:Glucuronosyltransferase; D000090264:UDP-Glucuronosyltransferase 1A9