Effect of androgen and estrogen on the hydroxylation of steroid hormones by rat liver microsomes.

Castration in male rats decreased the activities of testosterone and progesterone hydroxylations and reduced the magnitude of spectral change caused by testosterone and progesterone in liver microsomes, accompanying less marked decrease in microsomal P-450 content and NADPH-neotetrazolium reductase activities. The administration of testosterone or methyltestosterone to the castrated rats completely restored the hydroxylating activities and magnitude of the spectral change. The simultaneous injection of estradiol or diethylstilbestrol blocked the action of the androgens. These results suggest that androgen increases the binding capacity of P-450 with steroid hormones and makes an increase in the hydroxylating activities and that estrogen directly prevents the above action of androgen.