Stimulation of Lipid Peroxidation in Vivo by Injected Selenite and Lack of Stimulation by Selenate

Abstract

Male weanling rats were raised on diets, based on torula yeast, which were deficient in vitamin E and Se, or supplemented with these substances. They were injected i.p. with sodium selenite at 2 mg Se/kg or with sodium sulfite to give the same level of Na. Following injection, lipid peroxidation in vivo was estimated by monitoring the production of ethane, a volatile product formed on the peroxidation of .omega.-3-unsaturated fatty acids. In the hour following injection, vitamin E- and Se-deficient rats injected with selenite produced 15 times as much ethane as did controls injected with sulfite. All rats in this group died 1-4 h after injection. Rats fed diets supplemented with selenite showed only a 2- to 3-fold stimulation of ethane production by selenite and 75% survived. Rats fed diets supplemented with vitamin E did not produce more ethane in response to selenite injection and 75% survived. All 4 rats supplemented with both vitamin E and Se survived without showing increased ethane production. The increased vulnerability of vitamin E- and Se-deficient rats to acute selenite toxicity may involve peroxidation in vivo. Rats fed diets supplemented with vitamin E could survive at least twice as much selenite as rats deficient in Se and vitamin E. Seven-day survival figures for rats fed the basal diet and injected with selenite were: 1 mg Se/kg, 7/8; 2 mg Se/kg, 0/8. For rats supplemented with vitamin E the figures were 2 mg Se/kg, 7/8; 4 mg Se/kg, 2.8. When sodium selenate was injected into rats deficient in vitamin E and Se at 3 mg Se/kg it caused acute mortality without increasing peroxidation in vivo.