Breakdown of 5′-Adenine Nucleotides in Ischaemic Renal Cortex Estimated by Oxypurine Excretion during Perfusion

The catabolism of 5'-adenine nucleotides in the cortex of the rabbit kidney was studied during normothermic and hypothermic ischaemia. Changes were found in the cortical content of ATP, ADP, AMP, and SAN (the sum of 5'-adenine nucleotides) during ischaemia; those changes were delayed by hypothermia. The loss of SAN was found to be significantly correlated to the duration of normothermic as well as hypothermic ischaemia. The oxypurines hypoxanthine and xanthine and the nucleoside inosine were shown to be the final products of the catabolism of 5'-adenine nucleotides. An accumulation of hypoxanthine-xanthine and inosine in the tissue and a corresponding excretion in the perfusion fluid occurred simultaneously with the catabolism of 5'-adenine nucleotides, in equivalent amounts. It is concluded that determination of the amount of oxypurines excreted during kidney preservation is an indirect measure of the loss of SAN in the tissue, and a reflection of the changes in the metabolic state.