INHIBITION OF CANINE EXOCRINE PANCREATIC-SECRETION BY PEPTIDE YY IS MEDIATED BY PYY-PREFERRING Y2 RECEPTORS

It is still unclear, which receptor subtype, Y1 and/or Y2, mediates th e inhibitory action of PYY on exocrine pancreatic secretion. The prese nt study was undertaken to characterize functionally the Y receptor su btype that mediates the inhibition of exocrine pancreatic secretion by peptide YY (PYY). In eight conscious dogs with chronic gastric and pa ncreatic fistulas, Eve compared the action of intravenous infusion of 200 and 400 pmol/kg/h of the Y receptor agonists PYY 1-36, PYY 3-36, P YY 13-36, Pro(34)PYY 1-36, and NPY 1-36 on the pancreatic secretory re sponse to secretin (20.5 pmol/kg/h) and cerulein (29.6 pmol/kg/h). PYY 13-36, Pro(34)PYY 1-36, and NPY 1-36 were also studied by giving a fi vefold dose (1,000 and 2,000 pmol/kg/h). PYY 1-36 and the Y2, receptor agonist PYY 3-36 significantly inhibited pancreatic secretory respons es to secretin and cerulein, whereas inhibition by NPY 1-36 and the Y2 receptor agonist PYY 13-36 was attainable only at doses of 1,000 and 2,000 pmol/kg/h. The Y1 receptor agonist Pro(34)PYY 1-36 was without e ffect on pancreatic secretion, We conclude that in dogs the inhibition of exocrine pancreatic secretion by PYY is mediated via Y2 receptors of a PYY-preferring subtype.