Fig. 3. Absorption of glucose, fructose, and galactose. Glucose (glu), fructose (fru) and galactose (gal) derived from ingested carbohydrate containing foods enter the portal vein and are carried to the liver. The liver rapidly clears fru and gal from the circulation and a large proportion is stored as glycogen. Glucose on the other hand goes through the liver into the peripheral circulation where it stimulates insulin secretion.