THE INFLUENCE OF ESTRADIOL ON THE SECRETION OF GONADOTROPIC HORMONE IN ADULT PARABIOTIC RATS

Abstract

Continuous vaginal estrus was obtained in the normal partner of [female] parabiotic rats at an ay. of 39 days following ovariectomy of the other partner. Inj. of 1 to 3 [gamma] of estradiol per day into the ovariectomy part. changed the vaginal smear of the normal part. from continuous estrus to diestrus, the latter averaging 10 days and being followed by normal estrous cycles. After estradiol treatment was stopped, continuous vaginal estrus reappeared in the normal rat. Hypophysectomy of the ovariectomized partner of pairs in continuous estrus likewise produced a diestrus which was followed by normal estrous cycles. Estrogen prevents hypersecretion of gonadotrophic hormone by the pituitary gland of adult ovariectomized rats.