The addition of cupric acetate, a potent inhibitor of ethionine carcinogenesis, to a diet containing ethionine increased the ethionine toxicity in rats. The concentration of S adenosylethionine in liver was found to be significantly higher when compared to animals fed only ethionine in the diet. Ethionine forms a complex(es) with cupric acetate that is insoluble at a pH higher than 4; however, this complex can be solubilized at a low pH. Ethionine, if administered p.o. in the form of this complex, was absorbed from the intestinal lumen in the same order of magnitude as when administered alone; however, as the body weight increased over 200 g, the portion of absorbed ethionine decreased. The absorption of ethionine bound in the complex was completed within 16 hr compared to 2 hr for free ethionine. This time delay was accompanied by a shift in the concentration maximum of ethionine metabolites in the liver from 8 to 24 hr. When ethionine was administered alone, it was metabolized in the intestinal lumen as demonstrated by the analysis of the soluble intestinal contents; the presence of cupric acetate inhibited this process. Chromatographic analysis of ethionine metabolites in urine of rats treated by the complex revealed an increased excretion of ethionine sulfoxide and other ethionine metabolites at the expense of N acetylethionine sulfoxide. The increased concentration of S adenosylethionine in the liver in chronic experiments may be, at least partly, a result of a diminished capacity of the rat to detoxify (acetylate) ethionine sulfoxide, which is considered the main reserve pool of ethionine for the maintenance of a high level of S adenosylethionine.
|Original language||English (US)|
|Number of pages||9|
|Issue number||11 (II)|
|State||Published - Jan 1 1975|
ASJC Scopus subject areas
- Cancer Research