Regulation of purine nucleotide metabolism in hypoxic liver and intestine of rats: radical scavenging effects of allopurinol and oxypurinol.

: The relationship between nucleotide catabolism and generation of activated oxygen species was investigated in liver, hepatocytes and small intestine of rats. In severe hypoxia nucleotide degradation via xanthine oxidase and urate oxidase requires about half of the oxygen consumed. Data on the changes of nucleobase compounds in rat hepatocytes and small intestine during ischemia and reoxygenation and the effects of allopurinol and oxypurinol thereon are presented. From EPR measurements it is concluded that OH. radicals induce reactions of allopurinol yielding long-living products which are able to react with DMPO-OH with loss of its radical properties.