Androgen metabolism was investigated in normal human apocrine glands and in those isolated from age-matched patients with hidradenitis suppurativa. Axillary glands were isolated by shearing and androgen interconverting enzyme activities were measured in cell-free homogenates by incubation with [3H] dehydroepiandrosterone, [3H] androstenedione and [3H] testosterone. The activities (pmol/mg protein/min: mean + SEM) of 3 beta-hydroxysteroid dehydrogenase delta 4-5-isomerase (10.0 +/- 1.2 vs. 5.3 +/- 0.5: n = 5) and 17 beta-hydroxysteroid dehydrogenase (58.1 +/- 4.5 vs. 35.7 +/- 5.2: n = 5) were significantly lower (P less than 0.005) in hidradenitis suppurativa, whereas 5 alpha-reductase activity (12.5 +/- 2.3 vs. 12.5 +/- 2.0: n = 5) was similar. This report suggests that hidradenitis suppurativa cannot be attributed to exaggerated activities of end-organ androgen interconverting enzymes.