Transplantation of the Ovary to the Spleen in Rats with Persistent Estrus Resulting from Hypothalamic Lesions

Abstract

Persistent estrus has been induced in rats by electrolytic lesions located in the anterior hypothalamus. After 1 month of continuous vaginal cornification the ovaries contained large and cystic follicles but no corpora lutea. The lesions have thus disturbed the mechanism of rhythmic LH release that causes ovulation. These animals were then ovariectomized, 1 ovary being transplanted into the spleen; 1 month later the grafts showed regularly an intense luteinization. The anterior lobe of the pituitary contained numerous castration cells. Thus, estrogen deprivation induces LH release in constant estrus resulting from hypothalamic lesions. It is suggested, in agreement with Barraclough and Gorski that 2 regions within the hypothalamus control the gonadotrophic activity of the hypophysis. One is responsible for the cyclic ovulating LH discharge. The other one, more posteriorly located releases LH continuously. Its activity is depressed by estrogen.