The Study of Purine Utilization and Excretion in a Xanthinuric Man*

Abstract

Purine excretion was studied in a xanthinuric man. Xanthine and hypo-xanthine replaceduric acid. Xanthine made up 70 to 80% of the excreted purines and hypoxanthine 19 to 29%. The remaining purines were present in the trace amounts usually observed in normal man. The subject utilized adenine, hypoxanthine and guanine when they were administered intravenously. Studies with these C14 labelled purines indicated that adenine was utilized most avidly and guanine the least. However, once incorporated, the individual purines were freely interconverted. The data indicated that the enzymatic defect inhibited the oxidation of hypoxanthine to xanthine as well as the oxidation of xanthine to uric acid. In addition, it demostrated that an administered free purine base could be converted to another purine, incorporated into ribonucleic acid (RNA), methylated, degraded and excreted within 4 hours of administration.