Effect of Dietary Selenium on Selenoprotein W and Glutathione Peroxidase in 28 Tissues of the Rat

Abstract

The influence of deficient (0.004 μg/g), adequate (0.1 μg/g), and excessive (4.0 μg/g) levels of dietary selenium (Se) on the selenoprotein W (Se-W) content and glutathione peroxidase (GPX) activity was investigated in 28 tissues of the rat. GPX activity was found in all 28 tissues examined, and dietary selenium resulted in increased activities in all tissues, except for the spinal cord. Except for the brain, 0.1 μg Se per g diet resulted in significantly greater GPX activity in all tissues as compared with rats fed the deficient diet. When 4.0 μg Se per g diet was fed, however, this resulted in significantly greater activity in the brain as compared with the rats fed the deficient diet. Se-W was nondetectable in liver, thyroid, pancreas, pituitary, and eyes regardless of the level of Se fed. Se-W was not detected in heart, lungs, prostate, esophagus, small intestine, tongue, skin, diaphragm, and skeletal muscle from Se-deficient rats, but was present in these tissues when the two higher levels of Se were fed. In other tissues such as the kidney and seminal vesicles Se-W was detected only in rats fed 4.0 μg Se per g diet. These results indicate that the distribution of Se-W among rat tissues is more widespread than thought, and suggest that the regulation of Se-W by Se is markedly different between various tissues.