Studies on hypothalamo-pituitary corticoliberin system. V. The effects of gonadectomy and sex hormones on plasma ACTH and on the reactivity of the anterior pituitary gland to CRF.

The aim of the study was to investigate the effects of gonadectomy and sex hormones on responsiveness of anterior pituitary slices to synthetic CRF and on plasma ACTH level in male and female control, gonadectomised and testosterone or estradiol replaced rats. In animals of both sexes neither gonadectomy nor sex hormone replacement had an effect on plasma level of radioimmunoassayable ACTH. Adenohypophyseal ACTH output in vitro in response to CRF was unchanged by orchiectomy and lowered after testosterone replacement. Moreover, neither ovariectomy nor estradiol replacement had an effect on ACTH output by the entire adenohypophysis. Thus, since there were no apparent changes in plasma ACTH concentration among intact, gonadectomised and testosterone or estradiol replaced male and female rats as well as in responsiveness of the gland to CRF it seems that sex difference in the adrenocortical structure and function depends on action of sex hormones on adrenal and/or liver than on ACTH release on hypothalamic or pituitary level.