Effects of gonadal hormones and acth on the nature and rates of secretion of adrenocortical steroids by the rat

Abstract

Corticosterone (Cpd. B) secretion in adrenal venous blood of rats was measured by acid fluorescence and total steroid secretion by a modified Porter-Silber reaction. Ovariectomy is followed by decreased output as indicated by both techniques. Secretion of Cpd. B is depressed proportionately more than that of total steroids. Following administration of ACTH, Cpd. B secretion remained lower in ovariectomized rats, while total steroid secretion was increased to the same level as that in ACTH-stimulated controls. In male rats, no change in Cpd. B secretion rate was observed after castration alone. Total steroid output was elevated, resulting in a lower Cpd. B:total steroid ratio in orchiectomized rats also. After stimulation with ACTH, Cpd. B secretion was lower in castrates but total steroid secretion was equalized so that no change was observed in their ratio. Cortisone administration to intact male and female rats depressed steroid output but Cpd. B secretion was decreased more than total steroid secretion. Both Cpd. B and 3β, 5α-tetrahydrocorticosterone (Cpd. R) were demonstrated by double label isotope dilution in pooled adrenal venous blood from ovariectomized donors. The same technique was then applied to pooled samples from intact and gonadectomized rats of both sexes in 2 experiments. Cpd. R secretion was higher in every instance after gonadectomy. Cpd. B values paralleled those obtained earlier by the acid fluorescence technique. The data are consistent with the previously reported observation of increased adrenal 5α-reductase activity after either gonadectomy or administration of cortisone. They provide in vivo substantiation for the hypothesis that 5α-reduction is a physiologically significant mechanism for regulating adrenal corticosterone secretion. © 1971 by The Endocrine Society.