Galanin inhibits tolbutamide-stimulated insulin secretion in the perfused pig pancreas

Abstract

The neuropeptide galanin is known to inhibit insulin secretion in a variety of species. However, controversies exist regarding its action on insulin secretion in the perfused pig pancreas, since both inhibitory and stimulatory effects have been described. We therefore perfused the isolated porcine pancreatico-duodenal block with galanin (100 nmol/l) in the presence of 5 or 15 mmol/l glucose or with 5 mmol/l glucose and 10 mumol/l tolbutamide. We found that at this dose level, galanin did not affect insulin secretion stimulated by glucose alone. In contrast, galanin clearly suppressed tolbutamide-stimulated insulin secretion. Hence, we conclude that galanin has a weak influence on insulin secretion in the pig pancreas, being unable to inhibit glucose-stimulated insulin secretion at the dose level of 100 nmol/l. However, when active, galanin clearly inhibits insulin secretion also in the pig pancreas.