Inhibition of Ovarian Compensatory Hypertrophy by Hypothalamic Implantation of Gonadotrophin in Androgen-Sterilized Rats: Evidence for “Internal” Feedback1

Abstract

The influence of gonadotrophic preparations on the regulation of ovarian compensatory hypertrophy (OCH) has been studied by implanting these preparations into the basal hypothalamus at the time of unilateral ovariectomy in androgen-sterilized rats. Implantation of follicle stimulating hormone (FSH) or pregnant mare’s serum gonadotrophin (PMS) in the region of the median eminence markedly inhibited OCH without significantly altering uterine weight or the vaginal smear. Implantation of FSH or PMS in the cerebral cortex, FSH in the adenohypophysis or amygdala, or luteinizing hormone, human chorionic gonadotrophin, thyrotrophin, or adrenocorticotrophin in the medial basal hypothalamus did not influence OCH. It is concluded that FSH may participate in the regulation of pituitary activity by an internal feedback upon the hypothalamus. (Endocrinology82: 871, 1968)