INFLUENCE OF INSULIN AND EXTERNAL POTASSIUM CONCENTRATION ON SECRETORY RESPONSES TO CHOLECYS TOKININ-PANCREOZYMIN IN THE PANCREATIC ACINAR CELL

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Abstract
Using an isolated perfused rat pancreas preparation, the potentiating influence of insulin on cholecystokinin-pancreozymin (CCK-PZ)-induced secretory responses was examined when K concentration in the perfusing solution was varied. In the absence of insulin, partial replacement of KCl with NaCl produced a fall in both amylase output and pancreatic juice flow, which were induced by 1 mU/ml CCK-PZ, and the responses slowly returned to control levels after reintroduction of a standard concentration of KCl. Correlation between [K+]0 [external [K+]] and CCK-induced pancreatic juice flow or the amount of amylase released by CCK-PZ was found with [K+]0 from 1.5 to 5.6 mM. Rat insulin (20 mU/ml) potentiated the CCK-PZ-induced secretory responses. The potentiating effect of insulin was most marked when the perfusion solution contained 3 mM or more KCl. In the absence and in the presence of insulin, relation between the CCK-PZ-induced amylase output and pancreatic juice flow during perfusion with various [K+]0 was almost linear. These results are compatible with the view that insulin acts on a process common to fluid and enzyme secretion.