Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2003
Publication Date: 3/24/2004
Citation: Reeves, P.G. 2004. Varying media zinc, iron, and calcium affect uptake and transport of cadmium caco-2 cells [abstract]. Federation of American Societies for Experimental Biology Journal. 18:A528.
Technical Abstract: Marginal dietary Zn, Fe, and Ca increase the Cd content of rat enterocytes and increase Cd absorption. One theory is that the deficiencies up-regulate the metal transporters, which increase Cd transport into cells. This study assessed the effects of media concentrations of Zn, Fe, and Ca on Cd uptake and transport in monolayers of Caco-2 cells, a human enterocyte model. Cells were seeded onto membrane inserts with high pore density and grown to confluence in DME medium with 10% FBS. The medium contained 5 µM Zn, 4.5 µM Fe, and 1.8 mM Ca. From d 14-21, half of the cells were treated with 15 µM Zn, 9 µM Fe, and 3.6 mM Ca. The other half received the original media in a 2x2x2 design. In a separate study, cells were treated with or without 100 µM desferrioxamine (DFX) for 18 h to make them Fe deficient. Apical uptake and transport of 109**Cd were determined at pH 5.5 in the apical medium, the pH near that found in the duodenal lumen. High media Fe reduced 109**Cd uptake by 10% when Ca was normal and elevated it 25% when Ca was high. High media Ca decreased 109**Cd uptake by 60% and transport by 70%. Unexpectedly, 109**Cd uptake was 12% higher and transport 30% higher in cells treated with high Zn. Treating cells with DFX decreased 109**Cd uptake. The data suggest that intact rat duodenal cells and Caco-2 cells do not respond similarly with regard to the effects of Zn, Fe, and Ca status on Cd uptake and transport. Perhaps neither is a good model for intact human enterocytes.