Influence of fatty alcohol and other fatty acid derivatives on fatty acid uptake into rat intestinal epithelial cells.

We investigated the influence of various substrates on the uptake of long-chain fatty acid into IEC-6, rat intestinal epithelial cell line. The uptake of [3H]oleic acid into IEC-6 cells was a saturable function of the oleic acid concentration. Long-chain fatty acids significantly inhibited the oleic acid uptake into IEC-6 cells and shorter-chain fatty acids had little or no effect. Various fatty acid esters suppressed the oleic acid uptake into IEC-6. Fatty alcohols also inhibited oleic acid uptake into IEC-6 and the length of the carbon chain played an important role. These results suggest that long-chain fatty acid uptake was inhibited by the substrates which had a structure similar to long-chain fatty acids, especially those with a long carbon chain. At least two molecules, fatty acid translocase and fatty acid transport protein type 4, which are considered to be involved in the long-chain fatty acid transport into the cell, were expressed on IEC-6 cells, supporting the existence of the carrier-mediated system of long-chain fatty acid transport on IEC-6 cells.