Testosterone increases in men after a low dose of alcohol

BACKGROUND: Heavy acute alcohol drinking decreases blood testosterone in men due to an effect on the testicular level. An acute increase in blood testosterone levels after a low alcohol dose has, however, recently been reported in women. The objective of this investigation was to study the effect of a low alcohol dose on testosterone in men and further elucidate the mechanism behind the effect by using 4-methylpyrazole, an inhibitor of alcohol metabolism. METHODS: A double-blind placebo-controlled interventional crossover trial in random order (n = 13). RESULTS: After intake of alcohol (0.5 g/kg, 10% w/v), an acute increase in plasma testosterone (from 13.5 +/- 1.2 nmol/liter to 16.0 +/- 1.6 nmol/liter, mean +/- SEM; p < 0.05), a decrease in androstenedione (from 5.1 +/- 0.4 nmol/liter to 4.0 +/- 0.3 nmol/liter; p < 0.05), and an increase in the testosterone:androstenedione ratio (from 2.8 +/- 0.3 to 4.2 +/- 0.4; p < 0.01) were observed. The effects were not observed during pretreatment with 4-methylpyrazole (10-15 mg/kg orally), which inhibited the ethanol elimination rate by 37 +/- 3%. CONCLUSIONS: Alcohol intake affects the androgen balance in men through an effect mediated by the alcohol-induced change in the redox state in the liver.