Role of endogenous insulin in pancreatic secretion in rats.

BACKGROUND

Pancreatic exocrine tissue is influenced by islet hormones through the islet-acinar portal system. We investigated the role of endogenous insulin in pancreatic secretion in vivo in rats.

METHODS

Anesthetized rats were prepared by cannulation of the pancreatic duct, and pure pancreatic juice was collected. Pancreatic secretion was stimulated by intravenous infusion of cholecystokinin (CCK) (0.06 microgram/kg/h) with or without intravenous infusion of glucose (0.25 and 0.5 g/kg/h). The effect of intravenous infusion of glucose (0.5 g/kg/h) on pancreatic secretion stimulated by intraduodenal infusion of casein (400 mg/h) was also studied.

RESULTS

Intravenous infusion of glucose (0.5 g/kg/h) produced a significant elevation of plasma insulin and glucose levels. The basal pancreatic secretion was not influenced by glucose. Pancreatic secretion of juice volume, amylase, and trypsin in response to stimulation by CCK was significantly augmented by glucose (0.5 g/kg/h). Intravenous infusion of glucose also resulted in significant increases in casein-stimulated pancreatic juice volume, amylase and trypsin outputs.

CONCLUSION

Endogenously released insulin plays an important role in potentiating pancreatic secretion stimulated by exogenous CCK and intraduodenal infusion of casein.