AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 4 272-G279, Copyright © 1980 by American Physiological Society
Cholecystokinin-induced desensitization of enzyme secretion in dispersed acini from guinea pig pancreas
S. Abdelmoumene and J. D. Gardner
Incubating dispersed acini from guinea pig pancreas with cholecystokinin
and then washing the cells to remove cholecystokinin reduced the subsequent
stimulation of amylase secretion caused by pancreatic secretagogues, whose
actions are mediated by release of cellular calcium (i.e., cholecystokinin,
carbamylcholine, bombesin, litorin, physalaemin, and A23187), but did not
alter the stimulation caused by secretagogues whose actions are mediated by
cAMP (i.e., vasoactive intestinal peptide and secretin). This
cholecystokinin-induced desensitization was reversible, and the onset of
the process as well as its reversal were time- and temperature-dependent
changes. The concentrations of cholecystokinin required to cause
desensitization were greater than those required to cause maximal
stimulation of amylase secretion, and this finding suggests that the
submaximal stimulation of enzyme secretion seen with supramaximal
concentrations of cholecystokinin may be caused by cholecystokinin-induced
desensitization.
