Fructose intestinal epithelial cells

The final products of carbohydrate digestion—glucose, fructose, and galactose—are absorbed by intestinal epithelial cells and enter the blood. 

Glucose, fructose, and galactose, the final products generated by digestion of dietary carbohydrates, are absorbed by intestinal epithelial cells. 

XII. Effect of d-Fructose on the Energy Metabolism of Intestinal, Epithelial Cells... 

Fig. 27.12. Na -dependent and facilitative transporters in the intestinal epithelial cells. Both glucose and fructose are transported by the facilitated glucose transpxrrters on the luminal and serosal sides of the absorptive cells. Glucose and galactose are transported by the Na -glucose cotransporters on the luminal (mucosal) side of the absorptive cells.

Sugar The hydrolysis of sucrose in the intestine produces both glucose and fructose, which are transported across the epithelial cells by specific carrier proteins. The fructose is taken up solely by the liver. Fructose is metabolised in the liver to the triose phosphates, dihydroxy-acetone and glycer-aldehyde phosphates. These can be converted either to glucose or to acetyl-CoA for lipid synthesis. In addition, they can be converted to glycerol 3-phosphate which is required for, and stimulates, esterification of fatty acids. The resulting triacylglycerol is incorporated into the VLDL which is then secreted. In this way, fructose increases the blood level of VLDL (Chapter 11). 

Glucose, galactose, and fructose formed by the digestive enzymes are transported into the absorptive epithelial cells of the small intestine by protein-mediated Na -dependent active transport and facilitative diffusion. Monosaccharides are transported from these cells into the blood and circulate to the liver and peripheral tissues, where they are taken up by facilitative transporters. Facilitative transport of glucose across epithelial cells and other cell membranes is mediated by a family of tissue-specific glucose transport proteins (GLUT I-V). The type of transporter found in each cell reflects the role of glucose metabolism in that cell. 

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