The effects of delta9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on hydroxylation of estradiol and testosterone in rat liver microsomes were investigated. Acute and chronic treatment of male and female rats with either cannabinoid, 2 or 10 mg/kg, significantly elevated steroid hydroxylase activity. Acute administration of THC or CBD, 10 mg/kg, evoked no detectable changes in cytochrome P-450 levels, but a significant decrease in those of cytochrome b5. Chronic administration of THC or CBD, 2 mg/kg, decreased levels of cytochrome P-450, whereas cytochrome b5 levels appeared normal. Acute doses of THC or CBD at 10 mg/kg significantly depressed testosterone formation in testis microsomes. Chronic THC, 2 mg/kg, but not CBD, evoked the most dramatic decrease in testicular enzyme activity.
