Decreased glutathione peroxidase activity secondary to severe iron deficiency: a possible mechanism responsible for the shortened life span of the iron-deficient red cell.

Red cell glutathione peroxidase activity decreased to 26% of initial activity following the induction of severe iron deficiency in rabbits. The fall in enzyme activity does not appear to be related to anemia per se, aging of the animals during the course of the experiment, or a generalized decrease in enzyme protein synthesis. With iron repletion, glutathione peroxidase activity did not return to initial values for 10 wk after the hemoglobin concentration had returned to normal. During this period of time, the young red cell population had a higher concentration of GSH-Px activity than the older cells. In contrast, there is no age differential in the concentration of this enzyme in normal red cells, and during the induction of iron deficiency young red cells have decreased enzyme activity as compared to older cells. Reduction in glutathione peroxidase activity may result in increased oxidative damage to the irondeficient red cell. This, in turn, may be responsible for the previously reported membrane abnormalities and shortened red cell survival of iron-deficient red cells. It remains to be shown if glutathione peroxidase is dependent on iron for its synthesis or if the function of the enzyme is dependent on an iron-containing protein serving as an electron carrier.