EFFECTS OF DIETARY CARBOHYDRATE INTAKE ON ANTIOXIDANT ENZYME-ACTIVITYAND COPPER STATUS IN THE COPPER-DEFICIENT STREPTOZOTOCIN (STZ) DIABETIC RAT

The aim of this study was to investigate how dietary lactose, compared with sucrose, in association with copper deficiency influences the an tioxidant and copper status in the diabetic rat. Two groups of male ra ts (n = 12) were fed copper-deficient diets containing either 300 g/kg of sucrose or 300 g/kg of lactose in a pair-feeding regime for 35 day s. Six rats from each group were injected with streptozotocin to induc e diabetes. After a further 16 days the animals were killed and the li ver, heart, and kidney removed for the measurement of copper levels an d the activities of antioxidant and related enzymes. Diabetes resulted in higher hepatic and renal copper levels compared with controls. The copper content of the heart and kidney in diabetic rats consuming suc rose was also significantly higher than in those consuming lactose. Ca talase activity in the liver, heart, and kidney was significantly incr eased in diabetic rats compared with controls. Hepatic glutathione S-t ransferase and glucose-6-phosphate dehydrogenase and cardiac copper zi nc superoxide dismutase activities were also higher in diabetes. Sucro se, compared with lactose feeding, resulted in higher cytochrome c oxi dase and glutathione peroxidase activities in rite kidney while glucos e-6-phosphate dehydrogenase activity was lower. The combination of lac tose feeding and diabetes resulted in significantly higher activities of cardiac managanese superoxide dismutase and catalase and renal mang anese superoxide dismutase and glucose-6-phosphate dehydrogenase. Thes e results suggest that sucrose consumption compared with lactose appea rs to be associated with increased organ copper content and in general decreased antioxidant enzyme activities in copper-deficient diabetic rats.