Cholecystokinin-independent increases in pancreatic secretion
induced by dietary protein in chronic bile-pancreatic juice diverted
rats.
Hara, Hiroshi, Takashi Nishi, Hiroshi Narakino, and Takanori Kasai.
Department of Bioscience and Chemistry, Faculty of Agriculture,
Hokkaido University, Sapporo 060, Japan
APStracts 3:0059G, 1996.
Previously, we demonstrated that pancreatic enzyme secretion was
increased after feeding a 25% casein, fat-free diet in rats with
chronic bile-pancreatic juice (BPJ) diversion. We determined whether
cholecystokinin (CCK) or cholinergic pathway is associated with the
response of the pancreatic secretion after protein ingestion in the
diverted rats using a potent CCK antagonist, MK329 or FK480 and a
cholinergic blocker, atropine. Secretion rates of chymotrypsin and
trypsin in fasting state were very high seven days after a BPJ
diversion, and the hypersecretion of the proteases was markedly
reduced with an injection of MK329, FK480 or atropine, and was
further reduced by combined injection of FK480 and atropine. The
lowered secretion of the proteases in CCK antagonized rats was
increased after oral feeding of a protein diet and after a duodenal
instillation of some protein sources, especially hydrolysate of
guanidinated casein (HGC). The CCK-independent increases by HGC
instillation are completely depressed by atropine. In rats treated
with only atropine, the lowered secretion tended to be increased by a
duodenal instillation of HGC. Increasing the secretion after an
administration of protein source in CCK-antagonized rats was not
affected by bestatin, an inhibitor of brush border peptidases. We
conclude that the stimulatory effects of dietary protein on the
pancreatic enzyme secretion partially does not depend on CCK in
chronic BPJ-diverted rats, and the CCK-independent increase is
atropine-sensitive.
Received 20 July 1994; accepted in final form 5 February 1996.
APS Manuscript Number G271-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 March 96