T. Onaga et al., ROLE OF PEPTIDE YY IN REGULATION OF DUODENAL MOTILITY DURING THE INTERDIGESTIVE PERIOD IN SHEEP, Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 167(5), 1997, pp. 352-360
Temporal coordination between duodenal migrating myoelectric complexes
(MMC) and pancreatic exocrine secretion, and the effects of porcine p
eptide YY (PYY) on gastroduodenal motility and pancreatic exocrine sec
retion were examined during the interdigestive period in conscious mat
ure sheep. Fluid and enzyme secretions from the exocrine pancreas show
ed a periodic pattern corresponding to the phases of duodenal MMC, alt
hough these secretion rates were maintained at a high level during pha
se II in sheep. Intravenous continuous infusion of PYY at doses rangin
g from 50 to 200 pmol.kg(-1).h(-1) or intravenous bolus infusion of PY
Y at doses ranging from 50 to 200 pmol.kg(-1) showed a tendency to pro
long the first cycle of the duodenal MMC and significantly shorten the
second cycle. However, there was almost no effect on ruminal contract
ions from the PYY administration. In the pancreatic exocrine secretion
, PYY could inhibit only bicarbonate secretion at only the highest dos
e of 200 pmol.kg(-1). These results imply that endogenous PYY may play
a physiological role in the regulation of the duodenal MMC cycles in
sheep but not in ruminal contractions. PYY seems unlikely to regulate
the pancreatic exocrine secretion in normal sheep, because a supraphys
iological dose of PYY was required to inhibit the pancreatic exocrine
secretion.