Inhibition of selenium dependent glutathione peroxidase and superoxide dismutase in rats by diethyldithiocarbamate: effect of pre-administration of alpha-tocopherol.

Rats pre-administered with alpha-tocopherol (10 mgs/day) for 7 days afforded a significant protection at the tissue level against the lowering of superoxide dismutase and glutathione peroxidase, especially the selenium-dependent glutathione peroxidase. The protective action of alpha-tocopherol in the diethyldithiocarbamate treated rats may be attributed to its antioxidant/free radical scavenging action. It is concluded that selenium-dependent glutathione peroxidase and alpha-tocopherol act in a complementary fashion to block free radical formation.

In vivo inhibition of selenium dependent glutathione peroxidase and superoxide dismutase in rats by diethyldithiocarbamate.

Intraperitoneal injection of rats with diethyldithiocarbamate (1.2 g/kg body wt) led to maximum diminution of superoxide dismutase activity at 1 hr by 86 and 84% in liver and red blood cell respectively with a gradual return to the normal level at 48 hr after administration of injection. Significant inhibition of selenium-dependent glutathione peroxidase was also observed, which returned to normal at 48 hr after administration of injection. However, maximum decline in its activity was at 12 hr by 52 and 73% in liver and red blood cells respectively. No significant difference in tissue level of selenium-independent glutathione peroxidase was observed during time course study after diethyldithiocarbamate administration. It is possible that inhibition of superoxide dismutase by diethyldithiocarbamate leads to accumulation of superoxide anion which in turn inactivates selenium-dependent glutathione peroxidase by its reaction with selenium at the active site of the enzyme.