Previous studies from this laboratory have included reports on the serum concentrations of the following steroids in premenopausal and postmenopausal women: pregnenolone, 17-hydroxypregnenolone, progesterone, 17-hydroxyprogesterone, cortisol, corticosterone, dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, testosterone, dihydrotestosterone, estone, and estradiol 17-beta. In general the steroid levels were lower in postmenopausal subjects, and this difference was significant at P smaller than 0.05 for 8 of the steroids. The significantly decreased peripheral level of steroids in the postmenopausal state can be explained by decreases either in ovarian secretion of steroids or in ovarian stimulation of the adrenal cortex. Since the contribution of the adrenal cortex to the peripheral levels of dehydroepiandrosterone sulfate (DHEA-S) is greater than 95% in premenopausal women, a plausible explanation for the marked drop observed in peripheral DHEA-S levels after menopause is that the ovary influences the steroidogenic activity of the adrenal cortex. In such cases a decrease in the stimulation of the adrenal cortex by some ovarian steroids would be expected. Estrogen therapy in 10 postmenopausal women resulted in significant increases in the serum levels of 3 of the steroids compared to those in untreated subjects, confirming the postulate that ovarian estrogens stimulate the secretion of adrenal androgens.