Studies on the Endogenous Production of Oxalate in Man

Interest in oxalate metabolism has increased because of its importance in urinary stone formation. Oxalate is a metabolic endproduct in man and is excreted in the urine1. The two main precursors of oxalate are glyoxylic acid2 and ascorbic acid3. Serine is a minor precursor4. Glycine is thought to be the most important precursor of glyoxylic acid5. Glycine and ascorbic acid each contribute about 40% of the urinary excretion. Intestinal absorption is reported to be less than 10% of the ingested amount6.