SEX DIFFERENCE IN THE RELEASE OF LUTEINIZING HORMONE EVOKED BY PROGESTERONE

Publisher Website
Google Scholar
Abstract
SUMMARY Long-term gonadectomized female and male rats showed increased plasma luteinizing hormone (LH) activity (as measured by the ovarian ascorbic acid depletion method). A single injection of 20 μg. oestradiol benzoate or 2·5 mg. testosterone propionate after 3 days reduced the raised values significantly. Progesterone injected into gonadectomized rats primed with gonadal steroids exerts a positive feed-back action on the release of LH. In ovariectomized rats the injection of progesterone 3 days after a single injection of oestradiol or testosterone induced, a few hours later, a significant increase in plasma LH. In contrast, castrated male rats responded to progesterone with an increase in plasma LH only when they had been primed 3 days before with testosterone. This difference was not eliminated by gonadectomy on the first day of life. Androgen-sterilized ovariectomized rats failed to show an increase in plasma LH after progesterone when primed with testosterone but did so after priming with oestradiol. In male rats treated with testosterone in the early neonatal period, the normal LH release induced by progesterone in testosterone-primed animals was abolished. It is concluded that separate female and male patterns of LH release evoked by progesterone exist in the rat, and the difference between them is not determined by a postnatal differentiation in the neural mechanism which controls the secretion of LH.

This publication has 0 references indexed in Scilit: