Objective; To evaluate the changes of glutathione in the retina of rats at early stage of diabetes and the effect of zinc on glutathione and MDA in the retina. Methods; 72 Wistar rats weighing 200 + / - 50 g were made diabetic by injection with a single ip dose of streptozotocin (60 mg/kg). Another group of rats was simultaneously treated with streptozotocin (60 mg/kg) and a single ip dose of zinc chloride (ZnC12) (10 mg/kg). Control group was treated with buffer. Blood and tissue samples were collected at 24

48

and 72 h after - treatment in three groups. Results; Serum insulin was significantly increased 24h after treatment in both streptozotocin and steptozoto-cin plus ZnCl2 - treated groups

and then decreased markedly 48 and 72 h after treatment in both groups. Streptozotocin treatment depleted both retinal and pancreatic GSH contents. The decrease in retinal and pancreas GSH in streptozotocin - treated rats was. accompanied with a sustained increase in their MDA content. The combined administration of streptozotocin and zinc reversed the depleting effect on retinal and pancreatic GSH in streptozotocin -treated rats and reduced the elevations in MDA content of both retina and pancreas. Conclusion: The current results clearly indicate the beneficial effects of Zinc in both controlling hyperglycemia and protecting of the retina against oxidative stress in diabeteswhich may help set a new direction toward the development of effective treatments of DR.