THE FEEDBACK ACTION OF OVARIAN HORMONES IN THE FERRET

Abstract

SUMMARY The operation of an ovarian feedback mechanism in the control of pituitary function in the ferret has been tested in anoestrous and in oestrous animals by removing one gonad to determine whether compensatory hypertrophy of the remaining organ occurred, and by the administration of gonadal steroids. Compensatory ovarian hypertrophy was found after 10 days in both anoestrous and oestrous ferrets. Oestradiol or oestradiol benzoate occasionally caused ovulation after injection into oestrous females, and inhibition of follicular development occurred after s.c. implantation of a tablet of oestradiol. Ovulation also took place in two out of three ferrets injected with oestradiol benzoate (100 μg.) together with progesterone (2 mg.); one out of five animals given 2 mg. progesterone alone ovulated. These experiments show that release of gonadotrophin by the ferret hypophysis can be modified by gonadal steroids.