Reduction of Fe(III) is required for uptake of nonheme iron by Caco-2 cells

摘要: Differentiated cultures of Caco-2 human colonic cells were used to examine the importance reduction nonheme ferric iron, Fe(III), for transport across brush border surface. Cultures accumulated approximately 100 pmol Fe/(h.mg protein) when 10 mumol Fe(III) as nitrilotriacetic acid complex (1Fe:2NTA) was added apical compartment. Ascorbic enhanced cellular acquisition iron in a dose-dependent manner, with concentration low 8 mumol/L ascorbate increasing uptake by 50%. Similarly, rate from basolateral compartment increased 5.6- and 30-fold 1000 ascorbic acid, respectively, present chamber. Ascorbate-mediated stimulation temperature dependent required Fe(II), because it inhibited oxidase chelators Fe(II). Moreover, recycled dehydroascorbic acid. Ferricyanide Fe(II) also partially medium devoid Intact exhibited ferrireductase activity on surface that accounted majority incubated absence exogenous reductant. These data suggest within lumen or at cell is transfer this essential micronutrient intestinal