The potentiating influences of insulin on pancreozymin‐induced hyperpolarization and amylase release in the pancreatic acinar cell.

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Abstract
1. Insulin (1 mu./ml.) potentiated the release of amylase from isolated pancreas of rats perfused with erythrocyte‐containing medium and stimulated by 0‐5 m‐u. pancreozymin (Pz)/ml., whereas the same concentration of insulin failed to potentiate the response evoked by or 200 m‐u. PZ/ml. 2. Intracellular measurement of membrane potentials from the acinar cells of the same preparations showed that insulin (1 mu./ml.) simultaneously potentiates the hyperpolarization and amylase release in response to 0‐5 m‐u. PZ/ml. 3. These effects of insulin on the PZ‐induced responses were inhibited by ouabain (3 X 10(‐5) M). 4. The results suggest that insulin, in the concentration studied, has a potentiating action on the activity of an electrogenic Na pump, which maintains the hyperpolarization and amylase release during continuous stimulation with Pz. 5. Insulin in also potentiated the Pz‐induced amylase release in the rat pancreata in situ after vagotomy and ligature of the pyloric region.