Effects of Amino Acids and Dipeptides on the Uptake and Transport of Iron by Caco-2 Cells Cultured in Serum-Free Medium

This study was conducted to investigate the effect of five amino acids, aspartic acid, glutamic acid, histidine, cysteine and phenylalanine, and of two dipeptides, anserine and carnosine, on the uptake and transport of iron across monolayers of Caco-2 cells. Caco-2 cells were grown on polycarbonate membrane inserts in serum-free medium [DMEM plus ITS (5 mg/l insulin, 5 mg/l transferrin and 5 μg/l selenious acid)]. The anserine, carnosine, glutamic acid, histidine and aspartic acid, except for cysteine and phenylalanine, at 20 μM significantly increased the uptake and transport of iron. Iron uptake and rate of iron transport in the presence of aspartic acid at 20 μM were significantly greater than those of other test solutions. When the concentration of added carnosine, anserine, glutamic acid, histidine and phenylalanine was increased from 20 μM to 1 mM in the test solution, the uptake and transport of iron was further increased. The results of the present study indicated that aspartic acid, glutamic acid, histidine, and the dipeptides, anserine and carnosine, enhanced the uptake and transport of iron by Caco-2 cells.