Immunohistochemical localization of epinephrine, norepinephrine, catecholamine-synthesizing enzymes, and chromogranin in neuroendocrine cells and tumors

The immunohistochemical localization of epinephrine (E), norepinephrine (NE), and chromogranin was analyzed in normal and neoplastic neuroendocrine cells. The immunohistochemical detection of tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT) was used to distinguish between uptake and biosynthesis of catecholamines. E, NE, chromogranin, TH, DBH, and PNMT were found in the normal human adrenal medulla and in pheochromocytomas. Although many neuroendocrine tissues outside of the adrenal gland contained immunoreactive NE, only a small percentage of these tissues contained DBH. E was found in a few neuroendocrine tissues outside of the adrenal, including cardiac paragangliomas, and the enzyme PNMT was localized in some of these neoplasms. There was very close agreement between the localization of chromogranin and of catecholamines in normal and neoplastic neuroendocrine tissues. These results indicate that the presence of catecholamines and chromogranin in neuroendocrine cells and tumors within the adrenal medulla and in many other sites may be closely related.