Interrelationship between adenine and pyridine nucleotide metabolism in human erythrocyte life span

Adenyl and pyridine nucleotide production has been tested in the whole erythrocyte population and in cells of different age, separated by Percoll density gradient. Both the cellular nucleotide production from adenine and nicotinic acid and the related phosphoribosyltransferase activities show a decrease during cellular life span. Pyridine nucleotide production decay in intact cells parallels the NAPRT pattern, while APRT decrease during senescence is greater than cellular adenine nucleotide production decay.