The peripheral levels of pregnenolone (delta5-P), 17-hydroxypregnenolone (17-delta5-P), progesterone (P), 17-hydroxyprogesterone (17-P), testosterone (T), 5alpha-dihydrotestosterone (DHT), androstenedione (A), dehydroepiandrosterone (DHEA), its sulfate (DHEA-S), estrone (E1), estradiol-17beta (E2), and cortisol (F) were measured prior to and 1 1/2 and 9 months after removal of a right adrenal "compact cell" adenoma in an amenorrheic patient with a virilizing adrenal adenoma, under the following conditions: 1) control for 2 days, 2) dexamethasone, 0.5 mg, every 6 hours for 2 days, and 3) dexamethasone, 2 mg, every 6 hours for 2 days. Except for E1, E2, and F, the control levels of all steroids measured were elevated, markedly so for delta5-P, 17-delta5-P, DHEA, A, and DHEA-S. Dexamethasone treatment had no detectable effect on the steroid levels. Following removal of the adrenal adenoma, the levels of all steroids returned to normal. The patient became eumenorrheic, with marked improvement of her hirsutism and virilization.