The properties of UDP-glucuronyltransferase for cannabinoids in rat liver microsomes.
The glucuronidation of delta 9-tetrahydrocannabinol (delta 9-THC), cannabidiol (CBD) and cannabinol (CBN) in rat liver microsomes was studied. The enzyme activities for the cannabinoids were 26.3 (delta 9-THC), 52.9 (CBD) and 104.8 (CBN) pmol/min/mg protein. The apparent Km values of UDP-glucuronyltransferase for the cannabinoids were 0.29 (delta 9-THC), 0.18 (CBD) and 2.78 (CBN) mM, while Vmax were 40.3 (delta 9-THC), 104.9 (CBD) and 593.3 (CBN) pmol/min/mg protein. Following treatment of rats with 3-methylcholanthrene, the enzyme activities for delta 9-THC, CBD and CBN were increased 132, 43 and 1198%, respectively, whereas the corresponding increases in microsomes from phenobarbital-treated rats were 127, 13 and 97%, respectively. The cannabinoid glucuronidation was activated 2 to 3 folds by the addition of UDP-N-acetylglucosamine, but not activated by the addition of Triton X-100 in vitro. The properties of cannabinoid UDP-glucuronyltransferase were discussed from the above results.
D000818:Animals; D002185:Cannabidiol / Q000378:metabolism; D002186:Cannabinoids / Q000378:metabolism*; D002187:Cannabinol / Q000378:metabolism; D013759:Dronabinol / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D017830:Octoxynol; D010634:Phenobarbital / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000494:pharmacology
D002186:Cannabinoids; D002185:Cannabidiol; D011092:Polyethylene Glycols; D014537:Uridine Diphosphate N-Acetylglucosamine; D008748:Methylcholanthrene; D013759:Dronabinol; D002187:Cannabinol; D017830:Octoxynol; D014453:Glucuronosyltransferase; D010634:Phenobarbital