Nucleotide degradation and radical formation in ischemic and reperfused small intestine.

: Peroxidative loading during the reoxygenation of the rat small intestine following a complete ischemia was demonstrated in in vivo-experiments by the increases of the glutathione disulphide (GSSG): total glutathione ratio and the concentration of thiobarbituric acid-reactive substances (TBA-RS). The pretreatment of the rats with allopurinol diminished the accumulation of GSSG and of TBA-RS. From these effects was concluded that the purine nucleotide degradation is an important source of oxygen reduction products leading to peroxidations. The concentrations of nucleotides, nucleosides and nucleobases were measured by an ion-pair reversed-phase HPLC. The restoration of ATP and GTP concentrations during the reoxygenation period was accelerated by the application of allopurinol.