Studies on Protective Effect of Mercurial Toxicity by Selenium. I. Relationship between Protective Effects of Various Selenium Compounds on the Toxicity of Mercuric Chloride and Distributions of Mercury and Selenium in Rats Tissues

Abstract

The protective effect of six selenium compounds (sodium selenite, sodium selenate, selenocystine, selenocysteamine, selenocystamine, and selenomethionine) on the toxicity of mercuric chloride to rats was compared on the basis of survival rate, body weight change, and renal damage. Twenty-four hours after one of six selenium compounds was injected with mercuric chloride in rats, distribution of mercury and selenium in the tissues was determined by nondestructive neutron activation analysis. The protective effect of six selenium compounds on the toxicity of mercuric chloride decreased in the order of sodium selenite, sodium selenate, selenocystine, selenocysteamine, selenocystamine, and selenomethionine. Injection of the six selenium compounds characteristically altered the distribution of mercury in the rats and markedly increased the whole-body retention of mercury. The molar ratio of selenium to mercury in the tissues of animals simultaneously injected with mercuric chloride and selenium compound was nearly 1 : 1, except in a few cases. The result of this experiment demonstrated that mercury reacted peculiarly with selenium at an equimolar ratio in vivo and was transformed to a compound with lower toxicity. The difference in the protective effect among sodium selenite, sodium selenate, selenocystine, and selenomethionine on the toxicity of mercuric chloride was found to be explicable from the distributions of mercury and selenium, and the ratio of selenium to mercury in the tissues.