Factors influencing the release of cholecystokinin induced by gastrin-releasing peptide in man

We have studied the basal release of cholecystokinin (CCK) and the CCK response to gastrin-releasing peptide (GRP) in man. GRP infusion was followed by a substantial and immediate release of CCK. Pancreatico-duodenectomy or antrectomy with or without duodenal exclusion or antrectomy with truncal vagotomy did not significantly change the basal release of CCK or the GRP-induced CCK release. These results indicate that both basal and GRP-induced release of CCK predominantly originate from the small intestine below the duodenum and the upper part of the jejunum and is unchanged by duodenal exclusion and vagal denervation of the small intestine.