Glutathione oxidation and activation of pentose phosphate cycle during hydroperoxide metabolism. A comparison of livers from fed and fasted rats.
Perfusion of livers from fed and fasted rats with 0.07--0.1 mM t-butyl hydroperoxide for 15 min decreased the levels of reduced glutathione (GSH) by 1.5 mumol/g liver in both nutritional states. Glutathione disulfide (GSSG) was increased by 70 and 140 nmol/g liver and glutathione mixed disulfides enhanced by 45 and 150 nmol/g liver in livers from fed and fasted animals, respectively. The ratio of GSH/GSSG was decreased from 243 to 58 in fed animals, and from 122 to 8 in fasted animals. The increase of GSSG and the mixed disulfides was nearly parallel until an apparently critical low GSH content of 1.5 mumol/g was reached. Only in livers from fasted rats 14CO2-production from [1-14C]glucose was stimulated upon t-butyl hydroperoxide infusion at the employed rates. Flux of glucose through pentose phosphate cycle rose from 8 to 12% of glucose utilization via glycolysis, whereas in livers from fed animals this portion remained unchanged at 8% Dithio-erythritol reversed pentose phosphate cycle activity as well as GSSG and protein-bound glutathione contents to the original levels. In livers from fasted rats the activity of glucose-6-phosphate dehydrogenase was increased by 34% by t-butyl hydroperoxide infusion.
D000818:Animals; D002250:Carbon Radioisotopes; D005215:Fasting; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D010428:Pentosephosphates / Q000378:metabolism*; D010477:Perfusion; D010545:Peroxides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D020122:tert-Butylhydroperoxide
D002250:Carbon Radioisotopes; D010428:Pentosephosphates; D010545:Peroxides; D020122:tert-Butylhydroperoxide; D005954:Glucosephosphate Dehydrogenase; D005978:Glutathione