Morphine effects on the release of glucagon, insulin and somatostatin from the isolated, perfused rat pancreas.

The pancreatic glands from six male Wistar rats weighing between 200 and 250 g were isolated and perfused. After 30-min equilibration and 20-min basal periods, perfusion with 0.2 mg/ml of morphine for 20 min resulted in a significant (P < 0.05) increase in insulin release, with no changes in release of gucagon or somatostatin. After a recovery period of 20 min, a higher morphine concentration of 2 mg/ml was introduced for another 20-min period. With this morphine dose there were significant increases in release of insulin (P < 0.05), glucagon (P < 0.01) and somatostatin (P < 0.05). This shows that morphine induces the release of insulin, glucagon and somatostatin from pancreas in a dose-dependent way, and that release of insulin and glucagon is not primarily affected by regulation of somatostatin levels.