The Androgen-Sterilized Rat: Induction of Ovulation and Implantation by Luteinizing Hormone-Releasing Hormone

Abstract

It is well known that androgen treatment of newborn female rats results in persistent vaginal cornification and anovulation, a condition also associated with hypothalamic disorders. Our studies were designed to extend previously reported observations that LHRH will induce ovulation in these animals. A single injection of 25 nmol/kg LHRH induced a single estrous cycle, as judged by vaginal cytology, but subsequent LHRH injections were required at the end of each cycle to induce additional estrous cycles. Injections of LHRH induced ovulation; furthermore, the ovulation rate increased with subsequent treatments of LHRH, indicating a priming effect by the initial injection. Whereas only 1 out of 40 control rats mated, 8 of 43 LHRH-treated rats mated on the first day of cohabitation. In this initial study, mated animals were autopsied on days 14–15 and no pregnancies had occurred. In other studies, normal fertilized eggs were recovered on the first and second day after mating in LHRH-treated sterile rats. Furt...