Peptide YY inhibits exocrine pancreatic secretion in isolated perfused rat pancreas by Y1 receptors.

Peptide YY (PYY) inhibits exocrine pancreatic secretion in several species. Two receptors, Y1 and Y2, are known to mediate PYY actions. While PYY 1-36 binds equally to both receptor subtypes, a second endogenous form of PYY, PYY 3-36, selectively activates Y2 receptors. The importance of Y receptor subtypes for inhibition of exocrine pancreatic secretion by PYY is unknown. We studied the effects of PYY 1-36 on cholecystokinin octapeptide (CCK-8)-stimulated amylase secretion in an isolated perfused rat pancreas model. To characterize functionally the receptors involved we determined the effects of a Y1-selective agonist, [Pro34]PYY; a Y2 selective agonist, PYY 3-36; and neuropeptide Y (NPY) in this model. PYY 1-36 significantly inhibited stimulated amylase secretion in the denervated rat pancreas. [Pro34]PYY and NPY both inhibited exocrine pancreatic secretion as potently as PYY 1-36. Contrary to that, the Y2 selective agonist, PYY 3-36, was inactive. We conclude that PYY inhibits exocrine pancreatic secretion in this extrinsically denervated rat pancreas model by Y1 receptors.