The effect of calcitonin gene-related peptide on pancreatic blood flow and secretion in conscious dogs

Abstract

The effects of human α-calcitonin gene-related peptide (α-CGRP) and β-CGRP on pancreatic arterial (PA), superior mesenteric (SMA) and left gastric arterial (LGA) blood flows were studied by ultrasound transit-time blood flow meters in five conscious dogs. Intravenous injections of α-CGRP and β-CGRP (5–200 pmol/kg) induced a dose-related increase in PA flow and a dose-related decrease in its resistance. At lower doses, α-CGRP was more potent than β-CGRP, but their maximal responses were similar. The blood flow responses to α-CGRP (200 pmol/kg) were 153% of the basal flow in LGA, 313% in PA, and 534% in SMA, while those to VIP (100 pmol/kg) were 467% in LGA, 953% in PA and 163% in SMA. Somatostatin reduced blood flow in all arteries. α-CGRP, but not β-CGRP, at higher doses induced gastric contractions and pancreatic protein-rich secretion, which were blocked by atropine. These results suggest that CGRP in perivascular nerves in the pancreas may regulate pancreatic blood flow in dogs but its physiological function remains to be studied.