ALTERATION OF ANTIOXIDANT STATUS IN DIABETIC RATS BY CHRONIC EXPOSURETO PSYCHOLOGICAL STRESSORS

Antioxidant status was measured in heart, liver, kidney, lung, and ery throcytes of 2-week streptozotocin-diabetic male Wistar rats exposed t o chronic intermittent psychological stress consisting of 1 h of restr aint twice daily for 14 days. Diabetes reduced erythrocyte and heart a nd liver susceptibility to hydrogen peroxide-induced glutathione deple tion. Susceptibility to peroxide-induced thiobarbituric acid reactive substance (TEARS) formation increased in erythrocytes, liver, kidney, and lung but decreased in heart. Significant changes also occurred in glutathione levels (increased in heart and decreased in liver) and in the activities of catalase (reduced in liver and kidney), glutathione reductase (elevated in heart and liver), and glutathione peroxidase (d ecreased in liver and lung), but not Cu,Zn-superoxide dismutase. Stres s potentiated diabetes-associated hyperglycemia and attenuated diabete s-induced hyperlipidemia. In addition, the reduction in peroxide-induc ed glutathione depletion in heart and liver and the increased TEARS fo rmation in kidney and lung were reversed. Similarly, the diabetes-indu ced increase in liver glutathione reductase and decreases in liver and lung glutathione peroxidase activities were abolished by stress. Thus , the relative resistance of antioxidant systems to stress can be modi fied under pathologic conditions in which antioxidant alterations are present.