Glycine loading and urinary oxalate excretion.

One metabolic pathway for glycine leads to glyoxylate which is the precursor of oxalate. To investigate whether absorption of glycine solution in transurethral operations may promote precipitation of calcium oxalate stones, we collected urine for 24 h before and after an intravenous infusion of 22 g of glycine in 10 male volunteers. There were no significant changes in the urinary excretion of oxalate, calcium, or citrate. Urine volume and amino acid excretion increased, while the urine contained less potassium. These results provide no biochemical evidence of an increased risk of renal lithiasis due to glycine irrigation during transurethral operations.