AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 6 590-G598, Copyright © 1983 by American Physiological Society
Comparison of effects of neurotensin and fat on pancreatic stimulation in dogs
S. J. Konturek, J. Jaworek, M. Cieszkowski, W. Pawlik, J. Kania and S. R. Bloom
In six conscious dogs with esophageal, gastric, and pancreatic fistulas,
the effects of intravenous infusion of neurotensin and intraduodenal
instillation of sodium oleate on gastric and pancreatic secretion were
determined under basal conditions and after exogenous (secretin and
cholecystokinin octapeptides) or endogenous stimulants (feeding and
duodenal acidification). Neurotensin given intravenously in graded doses
(1.5-200 pmol . kg-1 . min-1) to fasted dogs produced a dose-dependent
stimulation of pancreatic bicarbonate and protein secretion reaching,
respectively, about 18 and 100% of maximal responses to secretin and
cholecystokinin octapeptide (CCK). Duodenal oleate in graded doses (0.5-16
mmol/h) resulted in a similar pattern of bicarbonate and protein secretion
but increased plasma neurotensin only to about 10% of that achieved with
infusion of exogenous neurotensin producing an equal rate of pancreatic
secretion. Neurotensin, like oleate, potentiated the action of secretin and
CCK on pancreatic bicarbonate and had additive effects on protein response
to these secretagogues. Both neurotensin and oleate increased pancreatic
response to liver extract meal kept in the stomach at constant pH (5.5) and
the response to sham feeding but decreased the response to ordinary
feeding, probably due to the inhibition of gastric acid secretion and
reduction of duodenal acidification. Neurotensin given intra-arterially
directly to the pancreas or to isolated intestinal segment increased dose
dependently the blood flow and oxygen consumption without affecting general
circulation. We conclude that 1) neurotensin mimics the pancreatic
secretory effects of intestinal fat, 2) neurotensin may contribute in part
to fat-induced stimulation of the pancreatic secretion, and 3) the
secretory effects of neurotensin are accompanied by a marked stimulation of
intestinal and pancreatic circulation and metabolism.
