BACKGROUND: Hyperprolactinemia has been linked with hyperandrogenism and hirsutism in some women. High plasma Dihydroandrosterone and DHA-S levels were reported in patients with hyperprolactinemia and a dissociation of adrenal androgen and cortisol secretion occurs in normal subjects. The mechanism has not been elucidated, but it has been suggested that pituitary factors other than ACTH modulate adrenal androgen synthesis, One candidate hormone is prolactin. Adrenal tissue has been found to possess prolactin receptors and prolactin has been shown to act synergistically with ACTH and lowers the activity of the enzyme 5a-reductase or 3B-hydroxysteroid dehydrogenase (3B-HSD). The aim of this study was to investigate the secretion of adrenal androgen metabolites in patients with idiopathic hyperprolactinemia and prolactinoma and to deterrnine the relationship with prolactin and androgens. METHODS: We measured 24 hour-urinary DHEA, androstenedione, androsterone, pregnenolone, tetrahydrocorticoid and cortisol in 16 normal controls and 5 patients with idiopathic hyperprolac-tinemia (HP) and 12 patients with prolactonoma in the early follicular phase. RESULTS: Urinary DHEA, AD (androsteredione), and androsterone, the metabolites of adrenal androgen, were significantly higher in both patients with idiopathic HP and prolactinoma compared with those in normal controls (p<0.05), whereas they were not different in both disease groups. Urinary pregnenolone levels, early metabolite of adrenal steroid synthesis, were lower in patients. In contrast, urinary tetrahydorcortisol and cortisol were higher in patients compared to controls. There was no difference in DHEA:androsterone ratio between patients and controls. And there were no correlation between prolactin levels and the levels of androgenic metabolites or clinical symptoms. CONCLUSION: Prolactin has a tropic effct on the secretion of androgens and steroids by the adrenal cortex. But prolactin levels were not correlated with androgen levels or clinical symptoms (amenorrhea), and it might have little effect on lowering the activity of 3B-HSD.