Induction of Prolactin Secretion by Implants of Estrogen Into the Hypothalamo-Hypophysial Region of Female Rats

Abstract

Implants of estradiol or estradiol diluted with cholesterol were located in the hypothalamo-hypophysial region or other areas of the central nervous system of normal female rats. Estradiol implants in either the median eminence region or the anterior lobe of the pituitary induced constant diestrus and evoked lobuloalveolar development of the mammae. The corpora lutea from these animals were enlarged and the vaginas were mucified. The anterior lobes were enlarged and contained slightly or markedly increased stores of prolactin. Control implants of estradiol in the globus pallidus or preoptic region had little or no effect. Furthermore, the implantation of blank tubes, or tubes containing only cholesterol, into the median eminence region did not evoke any changes. It is concluded that estradiol implanted in either median eminence or anterior lobe can evoke an increased release and synthesis of prolactin by the adenohypophysis. It is postulated that estrogen exerts a stimulatory effect on prolactin secretion by a local action on cells at both these sites. (Endocrinology75: 206, 1964)