Effect of Diethylstilbestrol-Induced Tumorigenesis on the Secretory Activity of the Rat Anterior Pituitary Gland1

PROLONGED estrogen treatment results in tumorigenesis of the anterior pituitary glands of rats and mice (Zondek, 1936; McEuen, Selye and Collip, 1936; Cramer and Horning, 1936). Such tumors do not arise until several months after the initiation of treatment and terminate in the death of the animal as a result of increased intracranial pressure (Nelson, 1941). Though the tumors have been studied extensively in the last two decades, the mechanism of induction has remained obscure. Several authors have proposed an association between the tumorigenic action and the effects of estrogen on pituitary secretory activity (Zondek, 1941; Gardner, 1953; and Furth, 1953).