Antioxidant alpha-tocopherol ameliorates glycemic control of GK rats, a model of type 2 diabetes

We have shown recently that oxidative stress by chronic hyperglycemia damag es the pancreatic beta-cells of GK rats, a model of non-obese type 2 diabet es, which may worsen diabetic condition and suggested the administration of antioxidants as a supportive therapy. To determine if natural antioxidant alpha-tocopherol (vitamin E) has beneficial effects on the glycemic control of type 2 diabetes, GK rats were fed a diet containing 0, 20 or 500 mg/kg diet alpha-tocopherol. Intraperitoneal glucose tolerance test revealed a si gnificant increment of insulin secretion at 30 min and a significant decrem ent of blood glucose levels at 30 and 120 min after glucose loading in the GK rats fed with high alpha-tocopherol diet. The levels of glycated hemoglo bin Ale, an indicator of glycemic control, were also reduced. Vitamin E sup plementation clearly ameliorated diabetic control of GK rats, suggesting th e importance of not only dietary supplementation of natural antioxidants bu t also other antioxidative intervention as a supportive therapy of type 2 d iabetic patients, (C) 2000 Federation of European Biochemical Societies.