Release of Pancreatic and Gastric Somatostatin-Like Immunoreactivity in Response to the Octapeptide of Cholecystokinin, Secretin Gastric Inhibitory Polypeptide, and Gastrin-17 in Dogs

The effects of the gastrointestinal hormones cholecystokinin- octapeptide (CCK-OP), secretin, gastric inhibitory polypeptide (GIP), and gastrin-17-I, infused at approximately their physiological rate, upon the release of pancreatic and gastric somatostatin-like immunoreactivity (SLI) were studied in dogs. In anesthetized dogs, CCK-OP, administered iv at a rate of 0.5 μg/kg·h, elicited increases in plasma levels of SLI of approximately 60 pg/ml in the inferior vena cava, 300 pg/ml in the pancreatic vein, 280 pg/ml in the fundic vein, and 300 pg/ml in the antral vein. During the infusion of secretin at a rate of 0.1 C.U./kg·h, inferior vena caval and gastric vein SLI levels did not change, although pancreatic vein SLI rose by 160 pg/ml with secretin administered at a supraphysiological rate of 1.0 C.U./kg·h, inferior vena caval SLI levels rose 30 pg/ml, pancreatic venous SLI levels rose 240 pg/ml, and fundic and antral venous SLI levels rose 120 and 160 pg/ml, respectively. GIP, infused at a rate of 1.0 μg/...