Interaction of caerulein, glucose, and amino acids on insulin secretion from the perfused rat pancreas

The effect of caerulein on insulin response to graded amounts of glucose from the isolated perfused rat pancreas was investigated in the presence or absence of an amino acids mixture. Caerulein at a concentration of 0.1 ng/ml which is a submaximal concentration for an effect on exocrine pancreatic secretion potentiated insulin responses to glucose concentrations less than 200 mg/dl, but produced no further increase when added to a glucose stimulus over a 200 mg/dl. However, in the presence of amino acids the insulin response to 200 mg/dl glucose was significantly potentiated by the stimulation of 0.1 ng/ml caerulein. The effectiveness of caerulein as an insulinotropic agent depended on the glucose concentration only when amino acids were present. These results indicate that caerulein, at a concentration which stimulate pancreatic exocrine secretion, has a synergistic effect on insulin response to glucose and amino acids and therefore raises the possibility that endogenously released CCK may contribute to the entero-insular axis.