Glucose-insulin interactions on exocrine secretion from the perfused rat pancreas.

The effects of glucose and insulin on pancreatic enzyme release have been investigated using the isolated perfused rat pancreas. Basal and caerulein-stimulated secretion was significantly less in the presence of 15 mM glucose than with 5 mM glucose, except at a supramaximal concentration of caerulein (10(-9) M) where secretion was similar in both groups. Addition of exogenous insulin also caused a reduction in enzyme secretion, but the time of onset of the inhibitory action was delayed compared to that observed with glucose. Furthermore, it was found that the effects of 15 mM glucose and exogenous insulin were not additive at the concentration used in these experiments, and that the inhibitory action of insulin was glucose-dependent. Such glucose-insulin interactions must play an important role in the modulation of pancreatic enzyme secretion.