[Antisecretory effects of YY peptide and neuropeptide Y at three levels of the small intestine in rats].

OBJECTIVES AND METHODS

The purpose of this study was to compare the effects of peptide YY (PYY) and neuropeptide Y (NPY) on VIP- and PGE2-stimulated intestinal net water flux at three different levels of the small intestine (duodenum, jejunum, ileum), by a technique of in situ closed loops in anaesthetised rats.

RESULTS

VIP-stimulated net water flux was efficiently inhibited by both peptides at all three intestinal levels studied; PYY (ID50 about 30 pmol/kg.h) was 3 to 18 fold more potent than NPY. PGE2-stimulated net water flux was also efficiently inhibited in the jejunum and ileum; PYY (ID50 about 10 pmol/kg.h) was 30 to 90 fold more potent than NPY. A 30% inhibition of PGE2-stimulated net water flux could only be achieved in the duodenum with the largest dose of either peptide used in this study.

CONCLUSIONS

PYY and NPY display potent inhibitory effects of stimulated net water flux at the three studied levels of the small intestine, except in the PGE2-stimulated duodenum. The PYY ID50s measured suggest that PYY may have a physiological action in regulating small intestinal water flux in the rat.