NUCLEOTIDE DEGRADATION AND OXYGEN RADICAL FORMATION DURING ISCHEMIA AND REPERFUSION OF RAT SMALL-INTESTINE

On the basis of studies on disturbances of energy metabolism and oxidative loading as two important components of cell damage in hypoxic rat liver criteria of nucleotide and oxygen radical metabolism of rat small intestine were measured in vivo during ischemia and reperfusion. On the one hand there exist in the small intestine the prerequisites for an extensive oxygen radical formation, on the other hand the capacity of antioxidative protective systems is low. An oxidative loading especially during reoxigenation period could be demonstrated. The purine degradation via xanthine oxidase reaction is the dominant source of oxygen radical formation. The concentrations of aldehydes as specific indicators of lipid peroxidation were determined. The accumulation of oxidized glutathione, the formation of thiobarbituric acid-reactive substances, the generation of aldehydes as secondary products of lipid peroxidation are reduced in presence of xanthine oxidoreductase inhibitors. Furthermore, inhibition of xanthine oxidoreductase improves the regeneration of ATP and GTP.