title: Effect of repeated administration of 11-hydroxy-delta 8-tetrahydrocannabinol, an active metabolite of delta 8-tetrahydrocannabinol, on the hepatic microsomal drug-metabolizing enzyme system of mice.
abstract: The effects of delta 8-tetrahydrocannabinol (delta 8-THC) and its major and active metabolite, 11-hydroxy-delta 8-tetrahydrocannabinol (11-OH-delta 8-THC), on the hepatic microsomal drug-metabolizing enzyme system were studied in mice. The repeated administration of 11-OH-delta 8-THC (5 mg/kg/day, i.v.) for 3 or 7 days increased significantly the activities of aniline hydroxylase and p-nitroanisole O-demethylase. By the same treatment, cytochrome P-450 content (3 days) or NADPH-cytochrome c reductase activity (7 days) was also increased significantly. The treatment with delta 8-THC for 7 days (5 mg/kg/day, i.v.) significantly increased aniline hydroxylase only. 11-OH-delta 8-THC increased the Vmax, but not the Km, values for both drug-metabolizing enzymes, whereas delta 8-THC decreases significantly the Km value (270 microM) for p-nitroanisole O-demethylase as compared with the control (398 microM). Repeated administration of these cannabinoids for 7 days also increased the metabolism of delta 8-THC by hepatic microsomes; this was attributed to an enhanced formation of 11-OH-delta 8-THC. In contrast, microsomal formation of 7 alpha-OH-delta 8-THC was decreased significantly by treatment with delta 8-THC. 11-OH-delta 8-THC, but not delta 8-THC, treatment increased the metabolism of 11-OH-delta 8-THC by hepatic microsomes. These findings indicate that delta 8-THC and 11-OH-delta 8-THC treatment can induce hepatic microsomal drug-metabolizing enzymes and affect differently the catalytic properties of the enzymes.
mesh_terms: D000815:Aniline Hydroxylase / Q000378:metabolism*; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001711:Biotransformation; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D008099:Liver / Q000033:anatomy & histology / Q000187:drug effects; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D009575:Nitroanisole O-Demethylase / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism*
chemical_list: C020367:11-hydroxy-delta(8)-tetrahydrocannabinol; D013759:Dronabinol; D009575:Nitroanisole O-Demethylase; D010088:Oxidoreductases; D000815:Aniline Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases