AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 5 715-G724, Copyright © 1989 by American Physiological Society
Deoxycholate-stimulated release of peptide YY from the isolated perfused rabbit left colon
G. H. Ballantyne, W. E. Longo, P. E. Savoca, T. E. Adrian, A. P. Vukasin, A. J. Bilchik, J. Sussman and I. M. Modlin
Department of Surgery Yale University School of Medicine, West Haven, Connecticut.
The purpose of this study was 1) to measure the effect of graded
concentrations of oleic acid and deoxycholic acid (DCA) on the release of
peptide YY (PYY) and enteroglucagon and 2) to test whether DCA-stimulated
release of PYY was neurally mediated by blocking neuronal conduction with
tetrodotoxin. Studies were performed in isolated left colons from New
Zealand White rabbits. Oleic acid in concentrations from 0.22 to 22 mM
suspended in 10 mM DCA significantly stimulated release of PYY (P less than
0.01) but resulted in no graded response (Bartlett's test, P = 0.15).
Similarly, oleic acid (2.2 mM) suspended with ursodeoxycholic acid (10 mM)
produced no increased release of PYY above that achieved by ursodeoxycholic
acid alone. In contrast, oleic acid (2.2 and 22 mM suspended with 10 mM
DCA) produced a graded release of enteroglucagon during the stimulated
period. Deoxycholic acid caused a concentration-dependent release of PYY
(1, 3.3, 10, and 25 mM) during the stimulated period. Deoxycholic acid (1
and 10 mM) did not significantly increase enteroglucagon release.
Tetrodotoxin blockade had no effect on release of PYY stimulated by 10 mM
DCA. Because PYY and enteroglucagon are both found in colonic endocrine
cells, these results suggest that the release of PYY and enteroglucagon are
mediated by specific secretagogues and not simply caused by noxious effects
of the agonists. Also, this study has demonstrated that DCA-stimulated
release of PYY is not dependent on neuronally mediated mechanisms.
