Inhibition of lipid peroxide formation by vertebrate blood serum

Abstract

Lipid peroxide formation in incubated rat brain homogenates was inhibited by all vertebrate blood sera tested. Rat and chicken sera contained both dialyzable and non-dialyzable inhibitors, whereas turtle, frog, and fish sera had only nondialyzable inhibitors. Chicken, turtle, and frog sera had two electrophoretically different inhibitors; rat and fish sera had only a single one. The inhibitor in rat was associated with an iron-binding protein believed to be siderophilin, and the mechanism of its action was chelation. The inhibitors of the other sera also seemed to be associated with the iron-binding proteins. More information on these proteins in the lower vertebrates is needed before the mechanism of action of these inhibitors can be established as conclusively as in the rat. The significance of these findings with respect to understanding the differences in radiation sensitivity of tissue antioxidant activity was discussed.