Suppression of circulating delta 4-androstenedione and dehydroepiandrosterone sulfate during oral glucose tolerance test in normal females.

Abstract

Extending a series of previous investigations on the regulatory interaction of insulin and androgens, this study tests the hypothesis that the physiological insulinemia after oral glucose suppresses circulating dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), and androstenedione (delta 4A) delta 4 in normal women. Accordingly, seven normal weight, ovulatory women were randomized to receive first either a 75 g glucose dose or a sham control for diurnal rhythm consisting of distilled water at 1700 h. After this insulin stimulus, DHEA-S suppressed below sham control at 90 and 120 min (P less than 0.05) whereas delta 4A suppress at 60, 90, and 120 min (P less than 0.05). Furthermore, as serum insulin increased after glucose, DHEA-S (r2 = 0.351, P less than 0.05) and delta 4A (r2 = 0.314, P less than 0.05) decreased in an inverse linear relationship with insulin. There was no significant suppression below sham at any point in time for DHEA, testosterone, or cortisol. Thus, the endogenous serum insulin response after oral glucose in normal women is associated with suppression of serum DHEA-S and delta 4A with absence of testosterone and cortisol suppression.