Epidermal growth factor regulates fatty acid uptake and metabolism in Caco-2 cells

Epidermal growth factor (EGF) has been reported to stimulate carbohydrate, amino acid, and electrolyte transport in the small intestine, but its effec ts on lipid transport Eire poorly documented. This study aimed to investiga te EGF effects on fatty acid uptake and esterification in a human enterocyt e cell Line (Caco-2). EGF inhibited cell uptake of [C-14]palmitate and mark edly reduced its incorporation into triglycerides. In contrast, the incorpo ration in phospholipids was enhanced. To elucidate the mechanisms involved, key steps of lipid synthesis were investigated. The amount of intestinal f atty acid-binding protein (I-FABP), which is thought to be important for fa tty acid absorption, and the activity of diacylglycerol acyltransferase (DG AT), an enzyme at the branch point of diacylglycerol utilization, were redu ced. EGF effects on DGAT and on palmitate esterification occurred at 2-10 n g/ml, whereas effects on I-FABP and palmitate uptake occurred only at 10 ng /ml. This suggests that EGF inhibited palmitate uptake by reducing the I-FA BP level and shifted its utilization from triglycerides to phospholipids by inhibiting DGAT. This increase in phospholipid synthesis might play a role in the restoration of enterocyte absorption function after intestinal muco sa injury.