Enkephalin- and Somatostatin-Like Immunoreactivities in Human Adrenal Medulla and Pheochromocytoma

By using the Coons indirect immunofluorescence technique, enkephalin-like immunoreactivity with a granular localization was observed in human adrenal medullary gland cells and pheochromocytomas. In two of the tumors and in a few adrenal gland cells, a somatostatin-like peptide could also be identified. Catecholamine cell types were visualized on adjacent sections with antisera to the synthesizing enzymes dopamine-β -hydroxylase [DBH; dopamine β -monooxygenase; 3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase (β -hydroxylating), EC 1.14.17.1] and phenylethanolamine-N-methyltransferase (PNMT; noradrenalin N-methyl-transferase; S-adenosyl-L-methionine: phenylethanolamine N-methyltransferase, EC 2.1.1.28). In the normal adrenal medulla more DBH-than PNMT-immunoreactive gland cells were observed. In the adrenal pheochromocytoma both DBH- and PNMT-positive cells were seen, whereas the two extra-adrenal tumors contained only DBH. These findings correlated well with plasms catecholamine measurements. Finally, enkephalin immunoreactive fibers and somatostatin immunoreactive cells were observed in a sympathetic ganglion extirpated together with one of the tumors.