Effect of carbachol on luminal release of somatostatin from isolated perfused rat duodenum.

The dynamic release of somatostatin-like immunoreactivity (SLI) from duodenum into the lumen was studied in the isolated, vascularly perfused rat duodenum. The luminal release of duodenal SLI was stimulated by a cholinergic agonist, carbachol, and the carbachol-induced release of SLI was completely blocked by atropine, but not by hexamethonium. These data suggest that the luminal release of SLI from rat duodenum is under the control of a cholinergic muscarinic stimulation. The ratio of somatostatin-14 to somatostatin-28 in picograms was about 1 during basal release but increased to approximately 2 during carbachol stimulation.