IMPAIRED GLUTATHIONE BIOSYNTHESIS IN THE ISCHEMIC-REPERFUSED RABBIT MYOCARDIUM

Non-protein thiols (NP-SH) and the activities of the glutathione statu s-regulating enzymes gamma-glutamylcysteine synthetase (G-GCS), gamma- glutamyl transpeptidase (G-GT) and glutathione reductase (GR) were ass essed in perfused rabbit hearts subjected to severe (60 min) or mild ( 7 min) total ischemia and 30 min reperfusion, Severe ischemia signific antly decreased NP-SH, which were further depressed on reperfusion tog ether with a significant decline in G-GCS activity; G-GT and GR activi ties were unchanged, Specific analytes were unaffected by mild ischemi a-reperfusion. Thus, impaired enzymatic biosynthesis of GSH is operati ve in the reperfused rabbit myocardium after 60 min ischemia, This phe nomenon may favour myocardial GSH depression and oxidative reperfusion injury after severe ischemia.