Pyy and glp-1 contribute to feedback inhibition from the canine
ileum and colon.
Wen, J., S. F. Phillips, M. G. Sarr, L. J. Kost, J. J. Holst.
Division of Gastroenterology and Internal Medicine, Department of
Surgery, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, and
Department of Medical Physiology, University of Copenhagen,
Denmark
APStracts 2:0123G, 1995.
To explore mechanisms whereby unabsorbed nutrients in the ileum
inhibit the upper gut ("ileal brake"), we perfused the canine
ileum or colon and monitored phase III in the duodenum. Fasting
motility was recorded when the ileum or colon was perfused with 154
mM NaCl, a mixed isotonic nutrient solution (Ensure), or individual
nutrients (maltose, casein hydrolysates or sodium oleate). Blood
samples were collected before and during the perfusions. The ileum
was also perfused with 154 mM NaCl while peptide YY (PYY) was infused
by vein. In both sets of experiments, plasma levels of PYY,
neurotensin and GLP-1 were measured. Ileal or colonic perfusion of
Ensure delayed phase III (MMC) in the duodenum, inhibited ileal
motility and increased plasma levels of PYY and GLP-1. Ileal casein
and oleate, and colonic casein also delayed the duodenal MMC. The MMC
cycle length and plasma levels of PYY were closely correlated.
Intravenous PYY prolonged the MMC cycle; an intravenous dose of 100
pmol/kg/h of PYY mimicked the effects of ileal Ensure. These results
support the hypothesis that PYY, and possibly GLP-1, participates in
the ileal brake. This negative feedback loop also effects the distal
small bowel. The proximal colon also triggers the feedback inhibition
of gut motility ("colonic brake").
Received 15 January 1995; accepted in final form 14 June 1995.
APS Manuscript Number G19-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.