Effects of SMS 201-995, a somatostatin analogue, on the exocrine pancreatic secretion and gut hormone release in dogs.

The effect of SMS 201-995, an analogue of somatostatin, on pancreatic exocrine secretion was investigated in both interdigestive and digestive states in dogs. In four dogs with gastric and Thomas duodenal cannulas, the pancreatic juice was collected by direct cannulation of the main pancreatic duct. SMS 201-995 was infused intravenously at doses of 0, 15, 30, 60, and 120 ng/kg/hr for 2 to 3 hours in the following experimental conditions: (1) interdigestive pancreatic secretion, (2) pancreatic secretion stimulated by the intravenous infusion of both secretin, 0.06 CU/kg/hr, and cholecystokinin octapeptide (CCK8), 0.03 microgram/kg/hr, and (3) pancreatic secretion after ingestion of a test meal. Pancreatic juice was analyzed for volume and outputs of bicarbonate and protein. Plasma levels of motilin, pancreatic polypeptide (PP), CCK, and secretin were determined by radioimmunoassay. SMS 201-995 inhibited significantly the pancreatic secretion and release of hormones, including secretin, CCK, PP, and motilin, in all three experimental conditions. The inhibitory action of SMS 201-995 on pancreatic secretion and hormone releases was dose dependent.