Chromatographic characterization of cardiac natriuret1c peptides from the goby

The atrium and ventricle of the euryhaline goby (Gillichlhys mirabilis) contain intestinal NaCl absorption-inhibiting activity typical of natriuretic peptides The cardiocytes of both heart chambers contain abundant secretory granules and, when probed with an antiserum to human-a-ANP, exhibit strong immunoreactivity Heat- and acid-treated extracts of goby atria and ventricles were purified on Sep-Pak columns before analysis by gel permeation and reversed-phase HPLC. ANP and VNP elution profiles were determined by radioimmunoassay with antisera directed against eel ANP and VNP Apparent goby ANP (immunoreactive (ir) ANP) and VNP (irVNP) displayed different elution profiles on both Chromatographie columns The relative appearance of irANP and irVNP from the gel permeation column was consistent with the greater molecular mass of VNP compared with ANP, additionally, a larger molecular mass form of irANP (proANP) was also detected Both irANP and irVNP were detected in atrial and ventricular extracts of the goby Since the crossreactivities of goby natriuretic peptides are not quantitatively defined, comparisons of ANP content relative to VNP are not possible, nevertheless, the ventricular content of both natriuretic peptides is greater than the atrial content, consistent with our previously reported electrophysiological bioassay data.