title: The influence of zinc, magnesium, and iron on calcium uptake in brush border membrane vesicles.
abstract: The effects of adding increasing concentrations of magnesium (Mg), zinc (Zn), and iron (Fe) on calcium (Ca) uptake into rat brush border membrane vesicles was measured. At ratios of 1:1, based on the RDA, none of these minerals were found to significantly decrease calcium uptake. Mg, however, inhibited Ca uptake at an RDA ratio of 3:1 (Mg:Ca). At higher RDA ratios (Zn:Ca 10:1), Zn also decreased Ca uptake. In a comparison of the molar ratios of the above cations, Zn inhibited Ca uptake the most (0.12:1), possibly by competing directly at high-affinity Ca binding sites. Fe did not decrease Ca uptake but rather demonstrated an enhancing effect at high concentrations (20:1). When mixtures of the above divalent cations were studied, the effects on Ca uptake could largely be explained by the actions of the ions individually.
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst 01003.
authors.forename: H A
authors.initials: HA
authors.lastname: Roth-Bassell
authors.forename: F M
authors.initials: FM
authors.lastname: Clydesdale
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects*; D007501:Iron / Q000494:pharmacology*; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D015032:Zinc / Q000494:pharmacology*
chemical_list: D007501:Iron; D008274:Magnesium; D015032:Zinc; D002118:Calcium