Interactions of methionine, vitamin E, and antioxidants in selenium toxicity in the rat.

TLDR: It is suggested that vitamin E and the fat-soluble antioxidants make the methyl group of methionine more available for selenium detoxification.

Abstract: Female Wistar albino rats were fed a low vitamin E diet based on peanut meal and containing 10 ppm selenium as Na2SeO4. Supplementation of the diet with either 0.5% DL-methionine (Met) or 0.05% rfi-a-tocopheryl acetate (E) alone gave little protection against the liver damage due to selenium. However, a combination of 0.5% Met plus 0.01 to 0.05% E gave increasingly better protection depending on the level of E added. Combinations of 0.5% Met plus 0.05% N,N'-diphenyl-p-phenylenedi- amine, l,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, or butylated hydroxytoluene were also effective against liver damage, whereas supplements of 0.5% Met plus 0.1% di- sodium ethylenediaminetetraacetate, 0.25% mA©thylA¨ne blue, or 0.5% ascorbic acid gave little or variable protection against selenium. Replacement of the 0.5% Met with equi- molar amounts of cysteine, betaine, or cysteine plus betaine gave variable results. Addition of 0.39% guanidoacetic acid to a diet supplemented with 0.5% Met and 0.05% E appeared to inhibit the protective effect of the Met-E combination. Selenium levels in the livers and kidneys of rats fed supplements which protected against sele nium poisoning were lower than those of the animals fed the unsupplemented selenifer- ous peanut meal diet. It is suggested that vitamin E and the fat-soluble antioxidants make the methyl group of methionine more available for selenium detoxification.