Purpose: The present study was conducted to extend our earlier study on the role of testosterone in the pathogenesis of urolithiasis and to further investigate the influence of sex hormone on the pathogenesis of calcium oxalate stone.
Materials and methods: Adult Sprague-Dawley rats were divided into 9 groups, each containing 10 rats. Two groups of rats were left untreated and served as male and female controls. Another 7 groups of rats were fed a 0.5% ethylene glycol (EG) lithogenic diet for 4 weeks. Among them, 2 groups were male and female rats, 2 groups were castrated, 2 groups were castrated and then were subcutaneously implanted with testosterone, and 1 group of intact female rats was also subcutaneously implanted with testosterone. The stone and crystal deposits were examined by infrared spectrometer and polarizing and scanning electron microscope, respectively. Serum testosterone, creatinine and electrolytes and the renal excretion of, oxalate, citrate and creatinine were determined.
Results: Subcutaneous implantation of exogenous testosterone restored calcium oxalate stone formation in castrated, EG-treated male rats (80%) and enhanced urolithiasis in castrated female rats receiving EG (40%). However, the testosterone effect was less striking in intact female rats fed EG (10%).
Conclusions: These data suggest that testosterone can promote and estrogen may inhibit calcium oxalate stone formation in EG-treated rats.