Objective: To investigate the presence of a dysregulation in steroid biosynthesis in women from southern Italy.Design: Controlled clinical study.Setting: Normal and hyperandrogenic women referred to the Endocrinology Unit of Federico II University Medical School of Naples.Patient(s): One hundred fifty untreated young hyperandrogenic women and 50 normal agematched women.Intervention(s): Morning (basal) blood samples obtained in the early follicular phase and after a long (360 minute) ACTH stimulation test.Main Outcome Measure(s): The adrenal maximal response was calculated as stimulus under curve areas (AUC 8 ), and all steroids were assayed using RIA methods.Result(s): A dysregulation of 21-hydroxylase was found in 22 patients (14.7%), with a prevalent increase of 17α-hydroxyprogesterone AUC, whereas in 9 hirsute women (6%), there was a prevalent significant increase in 11-deoxycortisol AUC. In 5 women (3.3%), DHEA and DHEAS basal and AUCs plasma levels were increased, suggesting an impaired 3β-olo-dehydrogenase activity. The remaining 114 hyperandrogenic women (76%) compose the nonadrenal group, with a probable diagnosis of primitive functional ovarian hyperandrogenism.Conclusion(s): Considering the high prevalence of hirsutism and oligomenorrhea in our female hyperandrogenic population, we suggest an adrenal hyperresponsiveness likely due to a dysregulation in enzymes related to androgen adrenal steroidogenesis.