Selenium Status and Glutathione Metabolism
Selenium, vitamin E, and sulfur amino acids have long been considered to serve as antioxidants that complement one another. Selenium is an essential component of intracellular and extracellular glutathione peroxidases. (See chapters 3 and 4.) Vitamin E is a membrane-associated molecule that scavenges free radicals, preventing damage to membrane lipids (Witting, 1980). Glutathione (GSH) reacts with free radicals nonenzymatically and is also a substrate for many enzyme systems. The central role of glutathione in oxidant defense has recently been strengthened by discoveries showing that it regenerates vitamin E and ascorbic acid from free radical metabolites of them (Meister, 1992). Deficiencies of selenium, vitamin E, and/or GSH often result in increased sensitivity to oxidant stress. The relationships of glutathione with the antioxidant nutrients are important. Figure 8.1 depicts the formation and fate of cellular GSH. Elements of the scheme that are affected by selenium deficiency are highlighted. The relationship between selenium and glutathione will be discussed in this chapter.
KeywordsGlutathione Cysteine Selenium NADPH Hydroperoxide
Unable to display preview. Download preview PDF.
- Hill, KE, Burk, RF. Effect of selenium deficiency and vitamin E deficiency on glutathione metabolism in isolated rat hepatocytes. J Biol Chem 257:10668 - 10672; 1982.Google Scholar
- Hill, KE, Burk, RF. Glutathione metabolism as affected by selenium deficiency. In:Wendel, A, ed. Selenium in Biology and Medicine. Berlin:Springer-Verlag; 1989, pp. 96 - 100.Google Scholar
- Hill, KE, Burk, RF, Lane, JM. Effect of selenium depletion and repletion on plasma glutathione and glutathione-dependent enzymes in the rat. J Nutr 117:99 - 104; 1987a.Google Scholar
- Hill, KE, Taylor, MA, Burk, RF. Influence of selenium deficiency on glutathione disulfide metabolism in isolated perfused rat heart. Biochim Biophys Acta 923:431 - 435; 1987b.Google Scholar
- Wendel, A, Pilz, W, Ladenstein, R, Sawatzki, G, Weser, U. Substrate- induced redox change of selenium in glutathione peroxidase studied by X- ray photoelectron spectroscopy. Biochim Biophys Acta 377:211—215; 1975.Google Scholar
- Witting, LA. Vitamin E and lipid antioxidants in free-redical-initiated reactions. In:Pryor, WA, ed. Free Radicals in Biology. New York:Academic Press; 1980, pp. 295 - 319.Google Scholar