Effect of gonadectomy on hepatic, lung and intestinal mixed function monooxygenase enzymes in the rat

Aryl hydrocarbon hydroxylase (AHH) and 7-ethoxycoumarin O-deethylase (ECD) activities of microsomes from liver, lungs, and intestine of control and gonadectomized male and female rats were examined. Estradiol-treated ovariectomized female rats and testosterone-treated castrated male rats were also employed. Castration decreased hepatic AHH and ECD activities by 50% and 27%, respectively, whereas ovariectomy had no effect on these enzymes. Testosterone treatment of castrated male animals returned AHH and ECD activities to control values. Estradiol treatment of the ovariectomized female rats had no effect on the activities of these two enzymes. Gonadectomy of either sex did not alter AHH or ECD activities in microsomes from lungs and intestinal mucosa. No sex differences in lung AHH activities or lung and intestinal ECD activities were noted. AHH activities of liver and intestinal mucosa were greater by 86% and 42%, respectively, in male rats as compared to the female rats. Castration decreased the hepatic cytochrome P-450 content by 15%, while ovariectomy had no effect. The hepatic cytochrome P-450 content of control male rats was 27% higher than in the females. Organ specific alterations of mixed function monooxygenase enzymes occur with castration of male animals but not following ovariectomy of female rats.