RELEASE OF GLUCAGON-LIKE PEPTIDE-1 (GLP-1) BY CARBOHYDRATES IN THE PERFUSED RAT ILEUM

The effect of various carbohydrates on glucagon-like peptide-1 (GLP-1) release was studied in the in vivo perfused rat ileum. GLP-1 concentr ations in the mesenteric venous effluent increased significantly after luminal perfusion with substrates of a sodium/glucose cotransporter ( D-glucose, D-galactose, methyl-alpha D-glucoside, and 3-O-methyl-D-glu cose). D-Fructose induced a sodium-independent release of GLP-1. Carbo hydrates like 2-deoxy-D-glucose and N-acetyl-D-glucosamine, which are not substrates of a luminal sodium/glucose or fructose transporter, di d not affect GLP-1 release. Since methyl-alpha D-glucoside is not a su bstrate of the basolateral glucose transport mechanism and 3-O-methyl- D-glucose is not metabolized within intestinal cells, it is concluded that intracellular metabolism of carbohydrates and intracellular remov al are not essential to induce GLP-1 secretion in rats.