ALTERATIONS IN TISSUE GLUTATHIONE ANTIOXIDANT SYSTEM IN STREPTOZOTOCIN-INDUCED DIABETIC RATS

Changes in tissue glutathione antioxidant system in streptozotocin-ind uced diabetic rats for a period of 15 weeks were examined. Total gluta thione level was significantly increased in kidney tissue, but were sl ightly decreased and increased in liver and heart tissues, respectivel y. The small changes in total glutathione level in the liver and heart , though not statistically significant, were associated with reciproca l alterations in the activity of gamma-glutamylcysteine synthetase (GC S). While the GCS activity was not changed in kidney tissue, the activ ity of gamma-glutathione peroxidase was significantly increased in kid ney tissue. Insulin treatment could completely or partly normalize alm ost all of these changes induced by diabetes. However, the decrease in hepatic glutathione S-transferases activity in diabetic rats was not reversed by the insulin treatment. The ensemble of results suggests th at the diabetes-induced alterations in tissue glutathione antioxidant system may possibly reflect an inter-organ antioxidant response to a g eneralized increase in tissue oxidative stress associated with diabete s.