Selenium and lead: mutual detoxifying effects.

Antagonistic toxic effects of selenium and lead were studied in growing rats. Chronic lead intoxication was produced by cutaneous application of lead naphthenate solution (80-200 mg Pb/kg body weight) for a period of 8 weeks and chronic selenium intoxication was induced by giving 5 ppm, 10 ppm and 15 ppm selenium in drinking water. The growth rate and food consumption of rats receiving selenium in addition to lead approached normal rate while animals treated with only one of them showed hampered growth rate and lower food consumption. The enzymatic activity of delta-aminolevulinic acid dehydrase (ALA-D) in whole blood, liver and kidney and liver P-450 enzyme activity were normal in rats receiving both selenium and lead. The enzymic activities assayed were, however, depressed in the animals receiving either lead or selenium. Assay of lead and selenium in liver, brain, kidney and blood was carried out. Rats receiving both metals and higher concentrations of these metals in the organs studied, as compared to those only receiving one component. The data seem to indicate that the effect of selenium on the toxic effects of lead is similar to its protective role against methylmercury intoxication.