AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 3 248-G252, Copyright © 1984 by American Physiological Society
Potentiating effect of secretin on cholecystokinin-stimulated pancreatic secretion in dogs
W. Y. Chey, K. Y. Lee, T. M. Chang, Y. F. Chen and L. Millikan
A possible potentiating effect of cholecystokinin octapeptide (CCK-OP) on
the action of secretin on exocrine pancreatic secretion was studied in five
dogs with gastric fistulas and modified Herrera pancreatic fistulas.
Secretin in a dose, 2.45 pmol (0.03 clinical units) X kg-1 X h-1, that
mimics the plasma secretin level in the postprandial state increased
pancreatic bicarbonate secretion, but the increase was not statistically
significant. CCK-OP in graded doses, 26.2, 52.5, 109, and 219 pmol (0.03,
0.06, 0.125, and 0.25 microgram) X kg-1 X h-1, given intravenously produced
a significant increase in both bicarbonate and protein secretion, and the
increase was dose related. The plasma concentrations of immunoreactive CCK
during intravenous infusion of CCK-OP in doses of 26.2 and 52.5 pmol X kg-1
X h-1 were found to mimic the postprandial plasma concentrations of
immunoreactive CCK in eight dogs. When CCK-OP in four graded doses was
added to intravenous infusion of secretin, 2.45 pmol X kg-1 X h-1, the
actual bicarbonate output at each dose level of CCK-OP was greater than the
sum of the bicarbonate outputs produced by secretin alone and CCK-OP alone
in a corresponding dose. Thus, we conclude that the action of secretin in a
physiological dose that mimics the plasma level of secretin after a meal is
potentiated by CCK-OP in a dose range that produces a plasma CCK-OP level
comparable with that in the postprandial state and vice versa. The study
indicates that, like secretin, CCK-OP is another necessary agent for
pancreatic secretion of bicarbonate during digestion.(ABSTRACT TRUNCATED AT
250 WORDS)
