Atrial natriuretic polypeptide in human adrenal pheochromocytoma: immunohistochemical and immunoelectron...

Using the immunoperoxidase and immunogold methods with specific antibody, we studied the atrial natriuretic polypeptide (ANP) in seven tumor tissues of six patients with adrenal pheochromocytoma. Light microscopically, the reaction product for ANP was observed in all seven tumor tissues. Intracytoplasmic immunoreaction product for ANP was finely granular. In four cases studied with the electron microscope, the immunogold stain for ANP was demonstrated in secretory granules of the tumor cells. A considerable amount of alpha-hANP immunoreactive substance was also extracted from two tumor tissues (67.2 and 28.7 pg/mg wet tissue). This is the first report of the human adrenal pheochromocytoma that contains immunoreactive ANP. These findings provide additional evidence for the multisecretory APUD cells of neural crest origin.