OVARIAN SENSITIVITY TO OVULATORY STIMULI IN THE ANDROGEN-INDUCED PERSISTENT-OESTROUS RATS

Abstract

ABSTRACT The ovarian response of adult rats made persistent-oestrus by the postnatal treatment with testosterone propionate was examined by determining the number of ova shed in response to small doses of LH and/or FSH, and placental gonadotrophins (PMSG or HCG). A dose of LH (10 μg/rat) estimated to be equivalent to twice the minimal amount secreted for ovulation in normal rats failed to release a normal complement of ova. The same dose of FSH induced ovulation in 40% of rats with an ova count of 5.7 ± 1.8/rat. Both placental gonadotrophins induced ovulation, although the ova yield was significantly below the normal oestrous control. It is inferred from these findings that the ovarian sensitivity of androgen-sterilized rats is far below that of the normal animals despite the presence of numerous follicles in the ovaries of the persistent-oestrous rats.