Peptide YY receptor distribution and subtype in the kidney : effect on renal hemodynamics and function in rats

This study characterizes the location and subtype of peptide YY (PYY) receptors in rat and rabbit kidney and the effect of PYY on renal function and renal hemodynamics in rats. Receptor autoradiography performed on kidney sections revealed a dense concentration of specific high-affinity binding sites [dissociation constant ( K d) = 0.7 ± 0.1 nM] in the papilla of the rat, as well as cortical and papillary binding in the rabbit (papilla, K d = 1.6 ± 0.6 nM) and some medullary binding in both species. In the rat papilla, neuropeptide Y (NPY) and the Y1 agonist [Leu31, Pro34]NPY competed with PYY for binding (K d = 1.1 ± 0.4 nM and 1.6 ± 0.5 nM, respectively), but NPY-(13—36) (Y2 agonist) and pancreatic polypeptide (PP, Y4 agonist) were without effect, demonstrating that the PYY receptor in the rat papilla is of the Y1 subtype. In the rabbit papilla, NPY and NPY-(13—36) competed with PYY (K d = 0.5 ± 0.1 and 3.1 ± 0.6 nM, respectively), but [Leu31, Pro34]NPY and PP were without effect, evidence that the PYY ...