Ferric iron absorption in rats: relationship to iron status, endogenous sulfhydryl and other redox components in the intestinal lumen.
Based on the hypothesis that Fe+3 must be reduced before Fe absorption, we investigated luminal factors that might participate in the physiological Fe+3 reduction. Rats were fed diets containing 7 mg Fe/kg diet [adequate iron (+Fe]) for 3 wk prior to a 10-min test of 59Fe absorption from an in vivo ligated duodenal segment. During absorption of 59Fe, the oxidation-reduction potential became more reducing and the pH rose in segment contents. There were small but significant differences between the -Fe and +Fe rats. In one experiment, the lumen environment was modified by bile duct ligation and/or intestinal perfusion prior to the absorption test. Ascorbic acid, nonprotein sulfhydryl compounds, Fe+2 and total ionizable Fe were measured in luminal contents. Nonprotein sulfhydryl concentration was positively correlated with, and the best predictor of, Fe absorption in -Fe rats.
Wien
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EM
U.S. Department of Agriculture-Agriculture Research Service, Plant, Soil and Nutrition Laboratory, Ithaca, NY 14853.
Van Campen
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DR
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D001652:Bile Ducts / Q000601:surgery; D005290:Ferric Compounds / Q000378:metabolism*; D005296:Ferrous Compounds / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007260:Infusion Pumps; D007413:Intestinal Mucosa / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008026:Ligation; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D005290:Ferric Compounds; D005296:Ferrous Compounds; D013438:Sulfhydryl Compounds; D007501:Iron; D001205:Ascorbic Acid