Effects of selenium diet on expression of selenoproteins in the lung of the rat.

In the present article the radiotracer techniques have been combined with biochemical separation procedures to investigate the effects of changes in the selenium status on the expression of the selenium-containing proteins in the lung and their subcellular fractions. Subcellular separation of the lung has been achieved by differential ultracentrifugation. The selenium-containing proteins in these compartments have been investigated by labeling of rats in vivo with (75)Se, gel electrophoretic separation of the proteins, and autoradiographic detection of the tracer. In the lung of the selenium-deficient animals, the selenium administered was used predominantly to restore the levels of the selenoproteins, while in the lung of the selenium-sufficient animals most of the selenium retained was incorporated into the glutathione peroxidase. Also, higher activity of this enzyme has been found in the lung of the selenium-sufficient animals. The differences in the specific incorporation of the element in the selenium deficiency into different compounds suggested that there are different metabolic pathways for selenium, strongly dependent on its status.