Effects of a low selenium status on the distribution and retention of selenium in the rat.
In the tissues of rats fed a selenium-deficient diet the changes in the selenium content and the retention of the element after administration of a small amount of selenium to the depleted animals were determined. In the liver and in the erythrocytes, which are the main glutathione peroxidase pools, the decrease in the selenium content was great and the retention in the depleted rats only slightly increased in comparison with the control animals fed sufficient amounts of the element. In the testes and in the adrenals the decreases in the selenium content were the smallest, and here retention was about 15 times greater than in the control animals. Also in other tissues, such as the thymus, spleen, bone and kidney, retention was considerably increased in the depleted rats. The results indicate that regulation mechanisms exist, which in nutritional selenium deficiency cause reduced excretion of the element and priority of supply to certain tissues. This, in turn, leads to a redistribution of selenium in the organism and, as the glutathione peroxidase decreases to a greater extent than the selenium, also to a redistribution of the element among its different binding forms. As the selenium content is most probably kept up in particular in sites in which the element is most needed, the findings suggest important functions of selenium in these tissues.