SUMMARYCortisol, androstenedione, testosterone, dehydroepiandrosterone sulphate (DHAS) and free dehydroepiandrosterone (DHA) were measured in plasma of ten women affected by amenorrhoea with hyperprolactinaemia and eleven women affected by secondary hypothalamic amenorrhoea; twelve normal women at the second day of the menstrual cycle were used as controls. All subjects were hospitalized and 17‐ketosteroids, 170H‐corticosteroids and total dehydroepiandrosterone were also measured in urine.Plasma DHAS was increased in all subjects affected by amenorrhoea with hyperprolactinaemia, while plasma DHA and urinary DHA were significantly increased in this group in comparison to other groups. Plasma cortisol, androstenedione and testosterone and urinary 17‐oxosteroids and 170H‐corticosteroids were not significantly different in the three groups.In subjects affected by amenorrhoea with hyperprolactinaemia treated with bromocriptine a clear decrease of DHAS correlating with a decrease of plasma prolactin was observed.Since in women DHAS seems to be almost exclusively secreted by the adrenal gland and most of the circulating DHA is derived from adrenal secretion, these data suggest that human prolactin can stimulate DHAS production by the adrenal