Résumé
Objective To detect normal rat jejunum epithelial cells to learn about the distribution of peptide YY(PYY)receptor and measured two important parameters of PYY receptor so as to explore the target that PYY binds to and display its physiological function.Methods Receptor radioligand assay was conducted by using 125I-PYY to detect normal rat jejunum epithelial cells.We also measured receptor dissociation constant(Kd),the affinity or the ability that the receptor could bind ligand;maximum binding capacity(Bmax),the concentration of binding site;and Hill coefficient.Results There were PYY receptors in normal rat jejunum epithelial cells.Dissociation constant(Kd)of PYY receptor was(386.69?129.95)pmol/L.Maximum binding capacity(Bmax)was(303.21?116.85)fmol/mg protein.Hill coefficient was 1.PYY receptor had high affinity.Conclusion There are distributions of PYY receptors in normal rat jejunum epithelial cells.Kd means that PYY receptor has high affinity.Bmax means that the number of receptors is limited and decides the characters of saturability.We think that PYY directly inhibits secretion by binding to PYY receptor in jejunum epithelial cells when PYY inhibiting jejunum secretion.