Nine chronic male alcoholics presenting with hypogonadism but without overt liver failure were examined under baseline conditions and after acute injection of gonadotropin releasing hormone (GnRH, 100 micrograms iv) and thyrotropin releasing hormone (TRH, 200 micrograms iv), performed at 60 min of a 3-h infusion of saline and 0.4 g/kg ethanol, respectively. Controls were 10 male adult volunteers examined under the same conditions. Six alcoholics and six controls underwent a third test with the infusion of 0.8 g/kg ethanol. Subjects were hospitalized and the infusion was started after a 48-h period of abstinence from alcohol. Tests were performed in random order at intervals of at least three weeks, always at 15:00 following a standard meal in the morning. Plasma levels of FSH, LH, prolactin (PRL) and testosterone (T) were measured by radioimmunoassay. Significantly higher levels of FSH, LH and PRL, and significantly lower levels of T were recorded in alcoholics vs. controls on plasma samples drawn at about 08:00 for three consecutive days. Ethanol infusion at the dose of 0.4 g/kg did not change the pattern of response to GnRH and TRH of controls and alcoholics. Doubling the alcohol dosage yielded a significant reduction of LH response in normal subjects whereas did not result in a similar effect in alcoholics. The mean LH increment of alcoholics was significantly less than that of normals at all times during saline and infusion of 0.4 g/kg ethanol; significance was not attained when the dose of ethanol was 0.8 g/kg.(ABSTRACT TRUNCATED AT 250 WORDS)