Radioimmunoassay for neuropeptide Y (NPY): chromatographic characterization of immunoreactivity in plasma and tissue extracts.
A sensitive and specific radioimmunoassay was developed to determine the occurrence and concentration of neuropeptide Y (NPY) in plasma and tissue extracts. Furthermore, NPY-like immunoreactivity (NPY-Li) was characterized by means of three different chromatographic systems. The NPY antiserum used (NI) did not cross-react with related peptides of the pancreatic polypeptide family except avian pancreatic polypeptide (1% cross-reactivity). Unextracted plasma contained high molecular weight proteins which interfered in the assay. Acid ethanol extraction removed this protein interference allowing a 90% recovery of NPY-Li. The content of NPY-Li in human plasma from healthy subjects was close to or below the detection limit (less than 22 pmol/l). Sympathetic nerve stimulation in the cat increased the output of NPY-Li from the splenic vein suggesting the release of this peptide upon sympathetic activation. The major peak of NPY-Li in spleen extracts and splenic vein plasma co-eluted with synthetic porcine NPY and a minor peak with larger Stokes radius was also present. The present radioimmunoassay enables further studies on the physiological and pathophysiological role of NPY.
D000818:Animals; D002415:Cats; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D007106:Immune Sera; D007553:Isotope Labeling; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000276:immunology; D009478:Neuropeptide Y; D011863:Radioimmunoassay / Q000379:methods*; D013048:Specimen Handling; D014018:Tissue Distribution
D007106:Immune Sera; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y