Effect of Sodium Selenite Supplementation on Glucose Intolerance and Pancreatic Oxidative Stress in Type 2 Diabetic Mice under Different Selenium Status

The objective of this study was to investigate the effect of various selenium (Se) status on glucose intolerance and pancreatic oxidative stress or the defense systems in Nagoya-Shibata-Yasuda (NSY) mice as the animal model for type 2 diabetes mellitus. To let the mice become Se-insufficient to Se-sufficient conditions, the NSY mice were given normal or Se-deficient diet with 0-7.0 mg/l Na2SeO3-containing drinking water for 6, 8 or 12 weeks. In NSY mice ingested normal diet, levels of blood glucose and plasma insulin after intraperitoneal glucose tolerance test (IPGTT) were not significantly affected by Na2SeO3-supplementation. In Se-deficient diet-treatment groups, however, the supplementation resulted in the decrease of blood glucose and the increase of plasma insulin after IPGTT. Although glutathione peroxidase (GPX) I activity in pancreas of the NSY mice ingested Se-deficient diet was augmented by Na2SeO3-supplementation, pancreatic glutathione was depressed by the supplementation, accompanying by the increase of 2-thiobarbituric acid-reactive substances. These results indicated that although the supplemented Na2SeO3 may not protect against oxidative stress in the pancreas of NSY mice under Se-insufficient condition, the Se compound improved glucose intolerance of the mice.