Salvage of circulating hypoxanthine by tissues of the mouse

Abstract

Hypoxanthine is an inefficient precursor of purine nucleotides in mouse tissues. In vitro, mouse erythrocytes salvage <10% of hypoxanthine (10 μM) added to whole blood in 30 min of incubation at 37 °C. In vivo, circulating hypoxanthine is rapidly degraded (>90% in 10 min) to allantoin and uric acid. All tissues examined (other than erythrocytes) converted small amounts of hypoxanthine to nucleotides, with kidney and lung being the most active tissues examined. It is estimated that <2% of circulating hypoxanthine is salvaged in the mouse; the remainder is catabolized.