Y2-type receptors for peptide YY on renal proximal tubular cells in the rabbit

By means of primary cell cultures and luminal and basolateral membrane vesicles a single class of high-affinity binding sites for peptide YY (PYY), a member of the pancreatic polypeptide (PP)-fold family of peptides, was identified on the vascular side of the tubular epithelium in the proximal convoluted tubule of rabbit kidney. The binding of mono-iodinated radiolabeled PYY was inhibited equally well by PYY and neuropeptide Y (NPY), whereas the potency of the third member of the family, PP, was 10(5) times lower. Because NPY immunoreactive nerves in the mammalian kidney are confined to vascular smooth muscle cells and the juxtaglomerular apparatus, we propose that the physiological ligand for this binding site is blood-borne PYY. The kidney PYY receptor was sensitive to guanine nucleotides and could be classified as belonging to the Y2-subtype of NPY receptors, thus resembling in its binding characteristics the hippocampal NPY receptor. The high amounts of Y2-type PYY receptors present on the proximal tubule cell in rabbit kidney should permit studies on the functions and mechanisms of actions of PYY.