GLP-1(7-36AMIDE) SECRETION FROM ISOLATED-PERFUSED CANINE INTESTINE ISCOUPLED WITH NA+ GLUCOSE COTRANSPORTER

The secretion of GLP-1(7-36amide) is stimulated by carbohydrate intake . In the present study, we investigated the relationship between gluco se absorption and GLP-1(7-36amide) secretion using the isolated perfus ed canine ileum. Both glucose absorption and GLP-1(7-36amide) secretio n were increased by the intraluminal administration of glucose in the presence of intraluminal Na+. The increases in both glucose absorption and GLP-1(7-36amide) secretion were abolished by the intraluminal adm inistration phlorizin, by the intraarterial administration of ouabain, or in the absence of intraluminal Na+. The mean concentration of gluc ose in the venous outflow was increased to 0.41 +/- 0.02 mmol/l by the intraluminal administration of glucose alone, whereas the intralumina l administration of phlorizin or the intraarterial administration of o uabain reduced it to 0.10 +/- 0.04 mmol/l and 0.07 +/- 0.04 mmol/l, re spectively, and the absence of intraluminal Na+ blocked it. The mean c oncentration of GLP-1(7-36amide) in the venous outflow was increased t o 9.19 +/- 1.64 pmol/l by the intraluminal administration glucose. How ever, it was blocked completely by the intraluminal administration phl orizin or in the absence of intraluminal Na+, and it reduced to 1.53 /- 0.62 pmol/l by the intraarterial administration of ouabain. These d ata suggest that the absorption of glucose stimulates the secretion of GLP-1(7-36amide) and that it is closely related to the sodium/glucose cotransporter.