Receptors on phaeochromocytoma cells for two members of the PP‐fold family — NPY and PP

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Abstract
Pancreatic polypeptide (PP) and neuropeptide Y (NPY) belong to a family of regulatory peptides which hold a distinct tertiary structure, the PP‐fold, even in dilute aqueous solution. High‐affinity receptors, specific for both PP and NPY, are described on the rat phaeochromocytoma cell line, PC‐12. The binding of [125I‐Tyr36]PP to PC‐12 cells was inhibited by concentrations of unlabeled PP which correspond to physiological concentrations of the hormone, 10−11‐10−9 mol/1. The affinity of the receptor for the neuropeptide, NPY, was 102‐times lower than that of the PP receptor. C‐terminal fragments of both PP (PP24–36) and NPY (NPY13–36) were between 102 ‐ and 103‐times less potent in displacing the radiolabeled 36‐amino‐acid peptides from their respective receptors. It is concluded that PC‐12 cells are suited for structure‐function studies of the PP‐fold peptides and studies on the cellular events following cellular binding of PP‐fold peptides.