Glucose and amino acid in enterocyte absorption metabolism and maturation

The main function of the porcine intestinal tract is nutrient digestion and absorption. This function is performed by the absorptive enterocytes, which are differentiated from the intestinal stem cells residing at the bottom of the crypt. Nutrients such as glucose and amino acids are transported, absorbed by various transporters embedded on the membranes of these enterocytes. Metabolism occurs in each cell along the crypt-villus axis (CVA). Because the intestinal epithelial cells are the most vigorous, self-renewing cells, regenerating from the crypt bottom to the villus tip in only three to five days, the CVA is an appealing organ for studying cell maturation. In this review, we examine the glucose and amino acid transporters expressed in the apical membrane, basolateral membrane, or the inside of the absorptive enterocytes. We also discuss glucose and amino acid metabolism in small epithelial cells, and show how these nutrients influence the proliferation and differentiation of an intestinal stem cell into one specialized cell type when they migrate from the bottom of the crypt to the tip of the villus.