MEDICAL PHYSIOLOGY

Detailed explanation-1: -Fructose is specifically and passively transported by the facilitative glucose transporter 5 (GLUT5, Slc2a5) across the intestinal apical membrane and then is transported from the cytosol to the blood by GLUT2 (Slc2a2).

Detailed explanation-2: -Dietary fructose moves from the intestinal lumen to the circulation through a facilitated passive transport [3] across enterocyte membranes by members of the facilitative glucose transport (GLUT; Slc2a) family [14].

Detailed explanation-3: -Glucose, galactose and fructose are tranported out of the enterocyte through another hexose transporter (called GLUT-2) in the basolateral membrane. These monosaccharides then diffuse “down” a concentration gradient into capillary blood within the villus.

Detailed explanation-4: -Conclusions: Fructose is transported transcellularly by facilitated diffusion and paracellularly (based on lactulose transport) via glucose-activated solution drag. In the human small intestine, free fructose and glucose transport does not occur via the disaccharidase system.

Detailed explanation-5: -The monosaccharide units, glucose, galactose and fructose are transported through the wall of the small intestine and then into the portal vein which then takes these elements straight to the liver.