SELENIUM AND GLUTATHIONE-PEROXIDASE TISSUE DISTRIBUTION IN RATS - EFFECT OF DIETARY-INTAKE AND TOTAL-BODY BURDEN OF SELENIUM

A series of experiments was performed to determine the effects of individual variability and dietary selenium (Se) concentration on tissue distribution of Se in rats. Experiment one used mature rats selected for high or low concentrations of Se in blood. Rats selected for high concentrations of Se in blood tended to have greater concentrations and amounts of Se in liver and erythrocytes than rats selected for low blood Se. Experiment two examined the distribution of Se in rats fed diets deficient, adequate or high (but not toxic) in Se. Kidney and liver accumulated Se in excess of dietary Se concentration at all dietary Se concentrations. Selenium concentrations in the muscle and vesicular gland reflected dietary Se concentrations, while the testes had the same amount of Se regardless of dietary intake. The largest Se pool in rats fed the deficient diet was the testes, whereas the muscle was the largest pool in rats fed a high Se diet. Changes in tissue distribution of Se suggest that some tissues have priority for Se when it is limiting. Other tissue pools of Se become saturated at high dietary intakes, and genetic differences may cause individual variation in deposition of Se into proteins other than GSH-Px.