Ovarian inhibin content in immature female rats following hypophysectomy: control by exogenous gonadotrophins

Abstract

ABSTRACT The effect of exogenous ovine gonadotrophins on ovarian inhibin content in hypophysectomized immature female rats was studied to determine which of the pituitary gonadotrophins control ovarian inhibin production in vivo. Inhibin and steroid contents of 27 000 g ovarian supernatants were measured by specific radioimmunoassay. Whereas injection of ovine (o)FSH resulted in dose-dependent increases in ovarian weight, progesterone and oestradiol content above that of control animals injected with diethylstilbestrol alone, injection of oLH was without significant effect. Similarly, ovarian inhibin content was not altered significantly by injection of oLH, but was increased in a dose-dependent manner by injection of oFSH. Concentrations of inhibin in serum were correlated directly with ovarian inhibin content. The results of this study indicate that ovarian inhibin content is increased by injection of oFSH but not oLH. It is likely, therefore, that inhibin production by small antral follicles is controlled by FSH activity alone. J. Endocr. (1988) 119, 185–189