Effects of intravenous infusions of cholecystokinin (CCK)-8 on exocrine and endocrine pancreatic secretion in conscious sheep.

The effects of cholecystokinin (CCK)-8 on both exocrine and endocrine pancreatic functions were examined simultaneously in five conscious sheep. Intravenous infusions of CCK-8 (0, 5, 10, 20, 30, 60, 120 and 240 pmol/kg/min for 40 min) induced dose-dependent increases in flow rate, and in protein and amylase outputs in pancreatic juice. The same CCK-8 infusions induced dose-dependent increases in plasma insulin, but no change in plasma glucagon concentrations. The threshold dose (10-30 pmol/kg/min) of CCK-8 infusion for stimulating insulin secretion was similar to that for stimulating amylase output. In conclusion, using amylase output as an indicator of physiological action, CCK is one of the potential candidates as a physiological regulator of insulin, but not glucagon secretion in sheep.