Both trypsin inhibitors and their protease complexes stimulate the
secretion of pancreatic enzymes and modify their levels in the rat
small intestine.
Pusztai, A, G Grant, S Bardocz, K. Baintner, S W B Ewen.
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, Scotland UK
and E Gelencs[acute]er, Central Food Research Institute, Budafoki ut
59, H-1111 Budapest, Hungary and Pathology Department, University of
Aberdeen Medical School, Aberdeen AB1 2ZZ, UK
APStracts 3:0233G, 1996.
Secretion of pancreatic digestive enzymes was measured in pancreatic
cannulated rats after duodenal stimulation with Kunitz or Bowman-Birk
protease inhibitors or their complexes with trypsin and/or
chymotrypsin. Both free and complexed inhibitors were bound by the
duodenal epithelium, stimulated the discharge of cholecystokinin and
significantly increased secretion rates of [alpha]-amylase,
trypsinogen and chymotrypsinogen. As secretion rates returned to
basal levels with cholecystokinin-A receptor antagonists, the
stimulation was likely to be cholecystokinin-mediated. Soya factors
also influenced the duodenal concentration of pancreatic enzymes
under simulated feeding conditions. Thus, the level of [alpha]
-amylase increased while the trypsin concentration decreased in rats
gavaged with free or complexed inhibitors. Same was true for
chymotrypsin using the Bowman-Birk inhibitor but the Kunitz inhibitor
and its trypsin complex actually raised the luminal concentration of
chymotrypsin. Accordingly, since soya inhibitors remained effective
in stimulating pancreatic secretion after elimination of their
inhibitory activity by complex formation, it is questionable that the
signal for cholecystokinin secretion was solely due to lowering of
duodenal protease levels.
Received 25 August 1994; accepted in final form 19 August 1996.
APS Manuscript Number G322-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996