Effects of hypophysectomy on sex differences in the induction and depression of hepatic drug-metabolizing enzymes in the rat.

The role of the pituitary gland in the effects of treatment with phenobarbital, methylcholanthrene and morphine on hepatic drug metabolism in adult male and adult female rats has been investigated. A marked sex difference in the effects of treatment with these three compounds on hepatic drug metabolizing enzymes in intact adult rats was observed. No sex differences in the effects of phenobarbital methylcholanthrene or morphine on hepatic drug metabolizing enzymes were observed after treatment of hypophysectomized adult male and hypophysectomized adult female rats. The results indicate that the pituitary gland plays an important role in the determination of sex differences in the response of hepatic drug metabolizing enzymes to inducing agents.