AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 4 715-G720, Copyright © 1989 by American Physiological Society
Inhibition of gastric and pancreatic secretion in dogs by CGRP: role of somatostatin
W. S. Helton, M. M. Mulholland, N. W. Bunnett and H. T. Debas
Department of Surgery, University of Washington, Seattle 98195.
The coexistence of calcitonin gene-related peptide (CGRP) and somatostatin
(SS) within the stomach and pancreas and the potent inhibitory effects of
both peptides on exocrine secretions from these organs suggest that they
are functionally related. To assess the potential role of SS in the
mediation of CGRP action, the effects of intravenous human CGRP (64, 132,
and 264 pmol.kg-1.h-1) and somatostatin-14 (SS-14; 100, 400, and 800
pmol.kg-1.h-1) on plasma levels of SS immunoreactivity (SS-IR) and on
pentagastrin-stimulated gastric and pancreatic secretion were compared in
conscious dogs. CGRP caused significant inhibition of gastric acid
(85-102%), pancreatic protein (63-86%), and pancreatic bicarbonate (74-89%)
outputs and a simultaneous dose-related rise (40-102 fmol/ml) in plasma
SS-IR. Cessation of CGRP infusion resulted in prompt return of plasma SS-IR
to basal levels and an increase in gastric and pancreatic secretion.
Although CGRP is a potent releasor of SS into the circulation, its
inhibitory action on gastric acid secretion cannot be explained solely by a
rise in plasma SS-IR. In the pancreas, in contrast to the stomach,
inhibition appears to be more closely related to a rise in circulating
level of SS-IR.
