Adrenal dysfunction has been reported in patients infected with the human immunodeficiency virus (HIV). To evaluate the prevalence and degree of adrenal dysfunction in HIV-infected patients, we performed a longitudinal study in 53 ambulatory HIV patients. The plasma cortisol, aldosterone, and dehydroepiandrosterone (DHEA) responses to cosyntropin (250 micrograms, i.v.) were evaluated at 6-month intervals for 24 months and compared to those of normal subjects. The basal and peak cortisol responses to cosyntropin were normal in all HIV patients during the study. There was no difference in the mean basal or stimulated cortisol measurements between Center for Disease Control (CDC) class II-III and CDC class IV patients. Although the mean peak aldosterone response to cosyntropin in HIV patients did not differ from that in normal subjects during the study, the aldosterone secretory capacity was significantly less in CDC class IV than CDC class II-III patients at 6- and 18-month intervals. In addition, there was an impaired aldosterone response to cosyntropin in 31-53% of CDC class IV patients and in only 0-26% of CDC class II-III patients. The mean peak DHEA response to cosyntropin in HIV patients was significantly less than that in normal subjects during the entire study. Basal plasma aldosterone, PRA, cortisol, and DHEA levels did not change in 25 HIV patients who were followed for the entire 24-month period. However, plasma ACTH in these 25 patients was significantly increased at 24 months (9.7 +/- 0.9 pmol/L) compared to that at study entry (7.0 +/- 0.7 pmol/L). Of these 25 patients, 8 had plasma ACTH concentrations that exceeded the normal range at 24 months. The subnormal aldosterone and DHEA secretion with normal cortisol production in these HIV patients is similar to the alterations in adrenal function reported in seriously ill patients without HIV infection. Although we found that clinically significant adrenal insufficiency is uncommon, the elevations in plasma ACTH in several patients at the end of our 2-yr study suggest that adrenocortical capacity may become compromised.