Receptor-mediated absorption of high molecular weight dextrans from intestinal tract

The absorption efficiency of [H-3]dextrans from the small intestine evaluated by the in situ closed loop technique was strongly dose-dependent, and was pronouncedly suppressed by the presence of sugars with structural features similar to those of the reducing end of dextran, such as isomaltose, glucose, and galactose. Isomaltitol, phenyl glucoside and mannose did not affect the dextran absorption. The in vitro permeation study using two chamber-diffusion cells showed that the permeation of [H-3]dextran was comparably inhibited by the addition of isomaltose or phlorizin, and also by lowering the temperature from 37 degrees C to 4 degrees C. These results indicate the presence of a specific receptor-mediated mechanism for the intestinal absorption of dextrans.