EFFECT OF CHOLECYSTOKININ AND RELATED PEPTIDES ON JEJUNAL TRANSEPITHELIAL HEXOSE-TRANSPORT IN THE SPRAGUE-DAWLEY RAT

An in situ dual vascular and luminal perfusion technique was used to s tudy the effect of cholecystokinin octapeptide (CCK-8) on the transpor t of hexoses by the jejunum of the Sprague-Dawley rat from the lumen t o the vascular bed. The lumen of the jejunum was perfused with hexoses in oxygenated Krebs buffer, while the superior mesenteric artery was infused with Krebs buffer containing Ficoll 70 as a plasma expander. C CK-8 (0.8-8 pM) in the vascular infusate selectively reduced hexose tr ansport in a dose-dependent manner by 20-47%, although having no effec t on L-glucose or L-leucine absorption. Vascular tetrodotoxin did not block CCK-8 inhibition, whereas a specific CCK-A receptor antagonist, lorglumide, did. The CCK-B receptor agonist cholecystokinin tetrapepti de had a small effect on hexose absorption, whereas somatostatin-14 an d -28 had no effect. These results suggest that cholecystokinin can de crease intestinal absorption of hexoses in the small intestine, acting via CCK-A-type receptors.