AJP - Gastrointestinal and Liver Physiology, Vol 241, Issue 2 109-G115, Copyright © 1981 by American Physiological Society
Studies on the inhibition of pancreatic secretion by luminal somatostatin
S. J. Konturek, J. Tasler, M. Cieszkowski, J. Jaworek, A. Arimura and A. V. Schally
The effects of somatostatin, instilled into the duodenum or administered
intravenously, on pancreatic response to endogenous (meal and duodenal
acidification) or exogenous (secretin and caerulein) stimulants were
compared in five dogs with gastric and pancreatic fistulas. Somatostatin,
whether applied topically to the duodenal mucosa or given intravenously,
resulted in qualitatively similar inhibition of pancreatic secretion of
water, bicarbonate, and enzyme protein, being about four to eight times
less potent after intraduodenal than after intravenous administration. A
meal-induced secretion appears to be the most sensitive to the inhibitory
action of intraduodenal somatostatin, probably because of the suppression
of gastric acid and serum gastrin secretin involved in the postprandial
stimulation of the exocrine pancreas. The inhibition of pancreatic
secretion by luminal somatostatin was accompanied by a significant increase
of plasma levels of the immunoreactive somatostatin, indicating that this
peptide can be absorbed intact across the intestinal mucosa. We conclude
that somatostatin administered into the gut lumen is absorbed into the
circulation and can inhibit pancreatic secretion both by the suppression of
the release of gastrointestinal hormones and by direct inhibitory action on
the exocrine pancreas.
