Characterization of aPY-like peptides in anglerfish brain using a novel radioimmunoassay for aPY-Gly.

Anglerfish peptide YG (aPY) was isolated from pancreatic islets of the anglerfish. Subsequent immunohistochemical and biochemical analyses demonstrated that anglerfish islet cells synthesize aPY. We have now developed and characterized a radioimmunoassay (RIA) for aPY and have examined extracts of anglerfish brain for aPY-like peptides. Brain extracts were subjected to gel filtration and high performance liquid chromatography (HPLC). Fractions from HPLC eluates were analyzed in the aPY RIA and also in a neuropeptide Y (NPY) RIA. A single peak of aPY-like immunoreactivity eluted from HPLC columns. The elution position of this aPY-like peptide coincided exactly with the aPY-Gly marker under several gradient conditions. Results from the NPY RIA confirmed the presence of several molecular forms of NPY-like immunoreactive peptides in the anglerfish brain. These results demonstrate the utility of the newly developed aPY RIA for studies of anglerfish brain peptides and extend our previous immunohistochemical demonstration of aPY-like staining in the anglerfish brain.