Interaction of dietary methylmercury and selenium on accumulation and retention of these substances in rat organs.

Abstract Four groups of male Wistar rats were fed the following regimen for 40 days: (1) 20 ppm methylmercury chloride (MMC); (2) 20 ppm MMC + 3 ppm sodium selenite; (3) 3 ppm sodium selenite; (4) basal diet. The basal diet which contained 0.4 ppm “organic selenium” originating mainly from fish meal and wheat was resumed on day 41. Protective effect of selenite over toxicity of methylmercury was observed in terms of both growth rate and morbidity. Concentrations of total mercury, methylmercury and selenium were determined on Days 0, 20, 41, 47, 54, and 61 in the brain, liver, kidney, and blood. It was noted that methylmercury increased accumulation of selenium in all the organs analyzed while selenium retention varied according to the type of selenium and the organs. Modification by selenite, despite its protective effect, remained equivocal in regard to the organ accumulation of mercury and its retention therein.