Studies on the Mechanism of Protective Effects of Selenium against the Toxicity of Methylmercury

Interaction of methylmercury and selenium was studied in order to examine the mechanism of protective effects of selenium against the toxicity of methylmercury, mainly using methylmercuric chloride labeled with carbon-14. It was found that discharge of 14C into respiratory excretion was markedly accelerated by the concurrent administration of sodium selenite and 14C-labeled methylmercuric chloride, as compared with control of a sigle administration of 14C-labeled methylmercuric chloride. That is, the total amount of 14C discharged during 48 hr after the concurrent administration, was about 5.5 times as much as that in a single administration of 14C-labeled methylmercury. The acceleration of demethylation of methylmercury seemed to be more responsible for the action of selenium. Secodly, the uptake of methylmercury into erythrocytes, was examined and then, the amount of mercury in erythrocytes showed a tendency to become lower in the group given selenium. It was found that the uptake of methylmercury into erythrocytes was inhibited by about 30% with the administration of selenite.