Influence of adrenalectomy and ovariectomy on gonadotrophin secretion

In order to gain additional information on the effects exerted by adrenal hormones on gonadotrophin secretion, adult female rats have been submitted concomitantly to adrenalectomy and ovariectomy; ovariectomized animals with intact adrenals served as controls. Serum levels and pituitary concentrations of LH and FSH have been measured on post-operation days 1, 2, 7, 14 and 28. It has been found that ovariectomy, when performed alone, induces a progressive but delayed release of LH and a rapid and constant release of FSH. Ovariectomy exerts only minor effects on the concentrations of pituitary LH, while providing a strong stimulus to the intrapituitary accumulation of FSH. Adrenalectomy, superimposed on ovariectomy, advances the release of LH, and at the 4-week interval, increases serum levels of this gonadotrophin to well above those found in animals submitted only to ovariectomy; the absence of the adrenals does not significantly alter the release of FSH. Adrenalectomy, added to gonadectomy, strongly facilitates the accumulation of LH in the anterior pituitary, but decreases the resynthesis of FSH. In conclusion, these data suggest that one or more factors of adrenal origin may: (1) inhibit the release of LH without affecting the release of FSH; (2) prevent the post-gonadectomy accumulation of LH in the anterior pituitary and facilitate the re-accumulation of FSH.