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- Title
Inositol phosphates inhibit uptake and transport of iron and zinc by a human intestinal cell line.
- Authors
Han, O; Failla, M L; Hill, A D; Morris, E R; Smith, J C, Jr
- Abstract
To examine the influence of inositol phosphates on the uptake and absorption of Fe and Zn, Caco-2 cells were grown on either plastic (uptake studies) or porous membranes in bicameral chambers (transport/absorption studies). Caco-2, a human colon adenocarcinoma cell line, was selected as the test cell because it spontaneously differentiates into polarized enterocyte-like cells at confluency. Uptake of Fe (added as Fe-nitrilotriacetate complex) from a calcium-free solution by fully differentiated cells was 37 pmol/cm2. Addition of 10-fold molar excess of individual inositol phosphates (IP3, IP4, IP5 or IP6) decreased Fe solubility by 13 to 25% and reduced Fe uptake by 50 to 65%. The rate of transport of Fe from the apical solution into the basolateral chamber [1.4 +/- 0.1 pmol/(h.cm2)] decreased (34-96%) in proportion to the degree of phosphorylation of the inositol derivative in the apical compartment. Uptake and transepithelial transport of Zn were 246 +/- 5 pmol/cm2 and 23 +/- 1 pmol/(h.cm2), respectively. The solubility, uptake and rate of transport of Zn also decreased in proportion to the degree of phosphorylation of inositol. These results demonstrate the inhibitory influence of IP3-IP6 on the uptake and transport of Fe and Zn and support the usefulness of the Caco-2 human cell line as an appropriate model for evaluating the effects of specific dietary factors on trace metal bioavailability.
- Publication
The Journal of nutrition, 1994, Vol 124, Issue 4, p580
- ISSN
0022-3166
- Publication type
Journal Article
- DOI
10.1093/jn/124.4.580