Effect of Glicentin-Related Peptides upon the Secretion of Insulin and Glucagon in the Canine Pancreas

Abstract

OHNEDA, A. and OHNEDA, M. Effect of Glicentin-Related Peptides upon the Secretion of Insulin and Glucagon in the Canine Pancreas. Tohoku J. exp. Med., 1988, 155 (2), 197-204 - In order to clarify responses of the endocrine pancreas to glicentin, four glicentin-related peptides were investigated in a local circulation preparation of the canine pancreas. These peptides were administered in a dosage of 200pmole for 10min into the pancreaticoduodenal artery under the continuous infusion of 0.5% arginine solution. In a group of six dogs, the administration of glicentin-related pancreatic peptide (GRPP) and glicentin 1-16 resulted in an increase in plasma insulin (IRI) and a decrease in plasma glucagon (IRG). In the other group of six dogs, the administration of glicentin 62-69 induced are increase in plasma IRI and a decrease in plasma IRG. Following the successive infusion of oxyntomodulin, both plasma IRI and IRG increased slightly. Porcine glucagon administered at the end of each experiment exerted a rise in blood glucose and plasma IRI in addition to an increase in plasma IRG. In comparison of the maximal responses of plasma IRI and IRG to these glicentin-related peptides, the administration of glicentin 1-16, 62-69 or GRPP elicited an increase in plasma IRI and a decrease in plasma IRG. In contrast, oxyntomodulin and glucagon increased both plasma IRI and IRG. The present study indicates that glicentinrelated peptides, both the N- and C-terminal portions, affect the endocrine function of the pancreas and suggests that glicentin released by nutrient ingestion plays an important role in the enteroinsular axis.