Relationship between the central regulation of gonadotropins and mating behavior in female rats;.

Abstract

Elsewhere in this volume Drs. McCann (pp. 1–21) and Clemens (pp. 23–53) report on the baffling array of hormones and other biologically active substances produced by the hypothalamus, the gonads, and the pituitary gland which are involved in the control of reproductive activities. The causal relationship in the female rat between the discharge of pituitary gonadotropins, the release of ovarian hormones, and the subsequent onset of sexual receptivity is fairly well understood. In the normal cyclic female rat on the morning of proestrus, the secretion of estrogens from the developing graafian follicle reaches peak values and, in turn, acts on the hypothalamus to trigger the ovulatory surge of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) via the release of the hypothalamic releasing factors, LH-releasing factor (LRF) and possible FSH-releasing factor (FRF). The surge in LH and FSH occurs on the afternoon of proestrus; ovulation takes place in the early hours of the following morning (estrus).