Characterization of peptide YY receptors in rabbit colonic mucosa

Abstract

Quantitative receptor autoradiography localized a high-affinity binding site for 125I-peptide YY to the mucosa in rabbit distal colon. Scatchard binding analysis revealed a single-affinity binding site ( K D = 0.29 nM ) with binding specificity similar to other peptide YY-preferring receptors ( peptide YY ≥ neuropeptide Y > pancreatic polypeptide ). Radioligand binding studies using colonic mucosal membranes confirmed high-affinity peptide YY binding sites ( K D = 0.26 nM ) with time, temperature, and protein dependence, as well as saturability characteristic of receptor-ligand binding. Selective peptide analogues showed a subpopulation of these 125I-peptide YY binding sites to resemble the Y 1-type neuropeptide Y receptor. Peptide YY may exert local antisecretory effects on the colonic epithelium via these binding sites.