Interruption of pseudopregnancy in rats by hemi-ovariectomy.

Abstract

Hemi-ovariectomy on days 1, 2 and 3 after the appearance of leukocytes in vaginal smears in rats (made pseudopregnant by reserpine injections at estrus) caused a return of proestrus between 2 and 3 days after operation in all animals. There was compensatory ovulation at the first or second postoperative proestrus, as shown by counting healthy implantation sites at laparotomy following a successful mating. Progesterone replacement immediately after hemiovariectomy successfully maintained the persistent leukocytic vaginal smears of pseudopregnancy in all animals so treated. Sham operation was without effect. (Endocrinology87:173,1970) THERE IS good evidence to indicate that the central nervous system chronically inhibits the secretion of prolactin in the rat (1–4). It has been postulated that the factor which stimulates luteotrophin secretion does so by suppressing this neural inhibition, and that, during pseudopregnancy, progesterone may maintain the secretion of luteotrophin by a positive feedback (3).