Dehydroepiandrosterone (3 beta-hydroxy-5-androsten-17-one; DHA) and DHA-sulfate are abundantly produced adrenal steroids, whose serum concentrations exceed those of other adrenal steroids. Serum concentrations of DHA and DHA-sulfate, in contrast to other adrenal steroids, exhibit a progressive age-related decline. The mechanism(s) for this selective decline in serum DHA and DHA-sulfate levels and the biologic function of these steroids remain unknown. Studies examining insulin's regulation of adrenal androgens are reviewed. These studies show that experimentally-induced hyperinsulinemia lowers serum DHA and DHA-sulfate levels, and suggest that insulin reduces serum concentrations of these steroids by inhibiting production rather than by increasing clearance. Studies examining the actions of short-term pharmacologic DHA administration to young nonobese and obese men are also reviewed. These studies suggest that DHA may possess hypolipidemic and, possibly, anti-obesity properties. They have failed, however, to demonstrate any effect of DHA on tissue insulin sensitivity.