Experimental studies on the direct action of steroid hormones on ovarian function. 2

Abstract

In the first report, it was demonstrated that the long-term administration of sex steroids (estrogen and progesterone) inhibited the ovarian function not only by the so-called feed back mechanism but also by the direct action on ovaries of mature and immature albino rats.In order to determine the direct action of those steroids on ovaries exactly, in this experiment, I used the hypophysectomized female albino rat without the endogenous gonadoropin release. After the long-term administration of estradiol benzoate or progesterone, combined gonadotropin injection could not induce the ovarian cholesterol and ascorbic acid depletion, which were detectable in the control animal group without the sex steroid administrations.From these experimental results, I conclude that under some conditions ovarian sex steroids, namely estrogen and progesterone, control the steroidogenesis in ovaries themselves through the reduction of reacitivities to gonadotropic actions.