There is a direct significant correlation (r = 0,49, p less than 0,01) between cumulative LH response to i.v. injection of 25 mug LRH and testosterone blood level in 17 women with an excess of endogenous androgens (plasmatic testosterone and/or urinary androsterone and etiocholanolone). The relation also exists if the patients are divided in two groups according to the origin of the dysfunction: polycystic ovaries (n = 9, r = 0,62, p less than 0.05) or hypercorticism (n = 8, r = 0,53, p less than 0.1). In the same patients there is no correlation between LH release and the sum of androsterone and etiocholanolone 24 hours urinary excretion (r = 0,21, p: NS); there is no correlation between basal testosterone blood levels and urinary metabolites (r = 0,19, p: NS). Our data suggest that testosterone (or a closely related metabolite) acts at the hypophyseal level to inhibit the spontaneous LH discharge hence increasing the pituitary hormonal stores. This action could be responsible for menstrual abnormalities often found in hirsut women.