Determinant role of testosterone in the pathogenesis of urolithiasis in rats.

By using an ethylene glycol-induced urolithiasis model, we assessed the role of testosterone in the pathogenesis of urolithiasis. The intact and castrated male and female rats were fed with 0.5% ethylene glycol in drinking water for four weeks. The renal excretions of oxalate, citrate and other electrolytes were measured, and the stone and crystal deposit were examined microscopically. The results showed that drinking a loading of 0.5% ethylene glycol for four weeks produced hyperoxaluria in all rats, but the intact male rats excreted more urinary oxalate than any other groups of rats. The ethylene glycol-fed rats exhibited hypocitraturia except the castrated male rats. However, urolithiasis occurred in intact male but not female rats. Castration in male rats fed with ethylene glycol dramatically decreased the incidence of renal stone from 71.4% (5/7) to 14.3% (1/7). On the other hand, there was still no renal stone formed in the oophorectomized female rats which received ethylene glycol treatment. These data indicate that serum testosterone level plays a determinant role in urolithiasis formation.