Alterations of the Plasma Selenium Concentrations and the Activities of Tissue Peroxide Metabolism Enzymes in Streptozotocin-Induced Diabetic Rats

Abstract

The activity of aortic glutathione peroxidase, a selenium-dependent enzyme, significantly decreased in rats 4 and 8 months after the injection of streptozotocin (STZ). Catalase activity was shown to occur at low levels in rat aorta and was not influenced by the diabetic state. Superoxide dismutase activity was less than detectable. The activity of selenium-dependent glutathione peroxidase in kidney, but not in lung and liver, increased in diabetic rats. Catalase and superoxide dismutase activities in the kidney were not altered. The plasma lipid peroxide value increased in diabetic rats. The selenium content in plasma of diabetic rats increased markedly while the increase in plasma glutathione peroxidase activities was insignificant. The observed abnormalities in plasma of STZ rats were improved by insulin treatment. The defects in glutathione peroxidase in the diabetic rat aorta were restored by insulin treatment. These results may suggest that the capacity of the antioxidative defense system in the aorta decreased in the diabetic state, and this may help clarify the mechanism of the pathogenesis of endothelial dysfunction associated with diabetes.

Selenium in diabetes: Effects of selenium on nephropathy in type I streptozotocin-induced diabetic rats

“…Dohi et al [44] described an increase of plasma selenium levels 4 months after streptozotocin injection, but this change was corrected if rats received insulin treatment. Selenium supplementations increased plasma selenium content compared with nonsupplemented diabetic or control rats.…”

Renal antioxidant enzyme mRNA levels are increased in rats with experimental diabetes mellitus

“…Cu,Zn-SOD has been found to be decreased [22,23] or comparable to normal controls [24][25][26], whereas catalase has been found to be decreased [22,27], increased [23], or comparable to normal [26]. The basis for the discrepancies of these studies is not clear, although differences in severity, duration, and treatment of diabetes may be indicated.…”

Diabetes and trace elements

“…An inverse association between insulin administration and urinary selenium in type II diabetics-patients who received insulin as part of their treatment excreted less selenium than those who did not [51,52]-has also been described.…”