The metabolism of ascorbic acid-1-C14 and oxalic acid-C14 in the rat.

It is known that oxalic acid is a product of ascorbic acid metabolism in the guinea pig (1) and rat (2), and is formed in man from unidentified precursors (3). Oxalates are also of interest because of their occasional toxicity and unexplained deposition. Ascorbic, dehydroascorbic, and 2,3diketogulonic acids are known to give rise to oxalic and threonic acids in approximately quantitative yields by chemical oxidation (4, 5). Although diketogulonic acid has no appreciable antiscorbutic value, it has been reported in the tissues and urine of the guinea pig (6, 7) and rat (8). Damron, Monier, Roe, and Weiss (7, 8) observed that under normal conditions dehydroascorbic and diketogulonic acids were formed only to a small extent from ascorbic acid in wivo, except when the animals were exposed to low temperatures. Studies of ascorbic acid-l-C’“, dehydroascorbic acid-l-C’*, 2,3-diketoguionic acid-l-c”, and oxalic acid-Cl* metabolism under approximately normal conditions in the rat are reported in the present paper. The results show that the 6-carbon acids give rise to appreciable quantities of urinary oxalate. Oxalic acid is not oxidized appreciably to carbon dioxide in viva, however, nor is there evidence of its entering metabolic pathways other than excretion. The data indicate a half life for ascorbic and oxalic acids, respectively, as 3.6 and 2.5 days in the rat.