Hexoses, notably fructose, glucose, and galactose generated in the lumen of the small intestine by breakdown of dietary carbohydrate, are taken up by enterocytes lining the microvilli of the small intestine and released from them into the blood. Uptake into enterocytes is mediated by two transporters localized on the luminal surfaces of the cells. SLC5A1, also known as SGLT1, mediates the co-transport of sodium ions and glucose and galactose, and SLC2A5, also known as GLUT5, mediates fructose uptake (Wright 1998). Tetrameric SLC2A2, also known as GLUT2, localized on the basolateral surfaces of enterocytes, mediates the release of these hexoses into the blood (Kellett & Brot-Laroche 2005; Wright et al. 2004).