Insulin, glucagon, and somatostatin secretion from isolated perfused rat and chicken pancreas-duodenum.

Insulin, glucagon, and somatostatin secretion were evaluated in the following isolated perfused models: rat pancreas-duodenum (both normal and streptozotocin-diabetic animals) and the chicken pancreas with and without duodenum. Insulin secretion in response to glucose or arginine was greater from the normal rat than either the diabetic rat or the chicken. Glucagon release from both species was suppressed by glucose and stimulated by arginine except that poor inhibition by glucose was found in the diabetic rat. Somatostatin could be measured in the effluent from both normal and diabetic rats, but the responses to glucose and arginine were variable and modest. Clear increases of secretion in the rat were only observed in response to a combination of glucose, arginine, theophylline, and isoproterenol. In contrast, the chicken somatostatin secretion was markedly stimulated by glucose and by arginine. In conclusion, the perfused chicken pancreas-duodenum has been shown to secrete large amounts of somatostatin in comparison to the rat and should prove to be a useful system for the study of D-cell regulation.

Inhibition of glucagon and insulin secretion from the perfused rat pancreas by a B-cell-selective somatostatin analog.

The isolated perfused rat pancreas was used to study the effects of somatostatin and the analog des-Asn5-[D-Trps, D-Ser13]-somatostatin on arginine-stimulated insulin and glucagon secretion. Even though the analog was found to inhibit glucagon secretion at concentrations of 10 and 100 ng/ml, it had a relatively more inhibitory effect on the B cell than on the A cell than did somatostatin itself. These data suggest that the A- and B-cell receptors for these two peptides differ.