• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.654-662
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• 1999

The purpose of this study was to investigate the effects of vitamin E on the antioxidative defense system of kidney in streptozotocin induced diabetic rats. Sprague Dawley male rats weighing 100$\pm$10g were randomly assigned to one normal and three STZ induced diabetic groups, which were subdivided into vitamin E free diet(DM 0E group), 40mg vitamin E per kg diet(DM 40E group) and 400mg vitamin E per kg diet(DM 400E group). Vitamin E level of normal group was 40 mg per kg diet. Diabetes was experimentally induced by intravenous injection of 55mg/kg of body weight of streptozotocin(STZ) in citrate buffer(pH 4.3) after 4 weeks feeding of experimental diets. Animals were sacrificed at the 6th day of diabetic states. There were no significant on body weights, food intakes, and food efficiency ratio before the diabetic occurrence. But after the injection of STZ, body weights and food efficiency ratios were significantly decreased and the food intakes was increased. Kidney weights were significantly increased in diabetic groups compared to normal group. However, there were no significant differences among the diabetic groups. Plasma insulin levels of diabetic groups were significantly decreased, whereas, blood sugar levels were increased compared to that of normal group. There were no significant differences among diabetic groups in plasma insulin and glucose levels. Activities of superoxide dismutase(SOD) in DM 0E and DM 40E groups were signi ficantly decreased by 33% and 27%, respectively, compared to normal group. But that of DM 400E group was increased by 35% compared to DM 0E group. Activity of glutathione peroxidase(GSHpx) in DM 0E group was decreased by 20% compared with normal group. GSHpx activity in DM 400E group was increased by 29% compared to normal group. The contents of vitamin E in kidney were 58% and 49% lower in DM 0E and DM 40E group, respectively, than normal group. There was no significant difference in renal vitamin E contents between DM-400E group and normal group. The contents of superoxide radical(O2 ) in kidney were 150% and 98%, respectively, higher in DM 0E and DM 40E groups than normalgroup. DM 400E and normal groups were similar levels in their superoxide radical contents of kidneys. These results indicate that vitamin E functioned as chain breaking antioxidant in kidney such as in other tissues.