[The effect of allopurinol on testosterone metabolism]

Plasma testosterone, dehydroepiandrosterone, 17-hydroxy-progesterone and estrogens were diminished in male renal stone patients under treatment with allopurinol, whereas urinary testosterone glucuronide was elevated. Since plasma LH (luteinizing hormone) was diminished it is concluded that allopurinol decreases the plasma testosterone level via an inhibition of LH secretion. Also in male rats treated with allopurinol, plasma testosterone and LH concentrations were diminished. The activities of NADPH-5 alpha-reductase and the testosterone hydroxylases in rat liver microsomes were decreased, UDP-glucuronyl transferase activity was elevated. delta 5-3 beta-Hydroxysteroid dehydrogenase/delta 4,5-isomerase and 17 beta-hydroxysteroid dehydrogenase in rat testes were unchanged.