Prevention of oxalate urolithiasis by some compounds

Male Wistar rats were fed a basal diet, Purina Laboratory Chow, and an oxalate calculi-producing diet (CPD). The CPD was the basal diet containing 3 per cent glycolic acid. Sodium pyruvate, DL-alanine, alpha-keto glutaric acid, thiamine pyrophosphate, and L-glutamic acid were added to the CPD to determine their effectiveness in preventing calculi formation. The effectiveness of methyl glyoxal was determined by adding it to the drinking water. Rats fed CPD for 4 weeks developed calculi in the ureters, bladder, renal tubules, and/or renal pelvis and papilla. Rats in groups fed alanine and/or pyruvate had no calculi in their renal tubules or ureters; additionally, these rats had a significant reduction in incidence and amount of deposits in the renal pelvis and bladder. Rats in groups fed alpha-keto glutaric acid, thiamine pyrophosphate, L-glutamic acid, and methyl glyoxal developed equally or more severe oxalate urolithiasis than those on CPD alone. Results of this study show that either pyruvate or alanine at appropriate levels may be beneficial in preventing oxalate urolith formation.