RÉSUMÉ
Nine women clinical features of polycystic ovarian syndrome (PCOS) were studied in order to establish the differential diagnosis with late-onset adrenal hyperplasia (LOAH). Their hirsutism was classified as moderate in five patients and severe in the remainig four cases. All patients had bilateral polycystic ovarian enlargement by ultrasound examination. As a control group five women with normal ovarian function without hirsutism were submitted to the same protocol of study. The patients studied as well as the women of the control group had basal serum determinations of pregnenolone (P5), 17 hydroxypregnenolone (17-OHP5), dehydroepiandrosterone (DHEA), pregesterone (P), 17-hydroxyprogesterone (17-OHP), androstenedione (A), testosterone and cortisol by radioimmunoassay techniques. The basal serum levels of androgens showed no correlation with the severity of hirsutism or with the ultrasound finding. An adrenal stimulation with synthetic adrenocorticotropic hormone (ACTH) to all women performed in order to assess their adrenal responsiveness. The analysis of the ratios between delta 5 and delta 4 steroids demonstrated a partial enzymatic blockade at the level of 3ß-o1-hydroxysteroid dehydrogenase (3-HDS) in three patients. The blockade was particulary in the conversion of P5 to P and 17-OHP5 to 17- OHP. The lack of delta 4 steroid secretion in the presence of normal increase of delta 5 precursors following ACTH was noted. These findings confirm the clinical use of the ACTH stimulation test to reveal the presence of enzymatic alterations in adrenal steroidogenesis in some patients previously considered to have PCOS. Since it was demonstrated that the conversion steps were affected in variable degrees, the presence of different isoenzymes of 3-HSD is suggested