Alleviation of Silver Toxicity by Selenite in the Rat in Relation to Tissue Glutathione Peroxidase

Abstract

Dietary Se (0.5 ppm Se supplied as sodium selenite to a casein-based diet containing 0.02 ppm Se and lacking in vitamin E) prevented the growth depression observed in rats receiving 76 ppm Ag in the water supply and markedly improved growth and survival of those given 751 ppm Ag. The Ag concentration of liver and possibly of kidney was increased by Se. Liver glutathione peroxidase activities from rats fed 0.5 ppm Se and given 76 and 751 ppm Ag for 52 days in their water were, respectively, 30% and 4% of those from control rats fed 0.5 ppmSe without Ag. In rats fed a diet, adequate in vitamin E (100 IU/kg) and Se (0.5 ppm as sodium selenite), administration of 751 ppm Ag in the water for 15 wk reduced liver GSH-Px activity to 5% of that from control rats receiving no Ag. GSH-Px activity of erythrocytes and kidney was decreased by Ag to 37% and 38%, respectively, of control values. It is concluded that in vivo administration of Ag dramatically decreased liver GSH-Px in rats fed Se-supplemented diets with or without vitamin E. Furthermore, supplemental Se (0.5 ppm) prevented the growth depression and mortality caused by Ag in rats fed a diet lacking vitamin E, while increasing the Ag concentration of liver and kidney.