Osamura RY et al. - In a study to examine pheochromocytomas for localization of catecholamine-synthesizing enzymes-tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT)-as well as the marker peptides for pheochrornocytomas, it seems that primary culture and immunoelectron microscopy suggested the processing and synthesis of adrenalin and MEAGL in the secretory granules. Seven extraadrenal pheochromocytornas were negative for PNMT suggesting the lack of adrenalin synthesis Methods
17 (10 adrenal and 7 extraadrenal) pheochromocytomas were examined immunohistochemically for the localization of catecholamine-synthesizing enzymes-TH, DBH, and PNMT-as well as the marker peptides for pheochrornocytomas (ie, MEAGL)
Normal adult, fetal, and newborn human adrenal medullas were also examined
Results
6 adrenal pheochromocytomas showed immunohistochernically positive staining for PNMT; 5 of these demonstrated elevated serum adrenalin levels, indicating morphofunctional correlation
PNMT-positive cells were mostly positive for TH but did not show co-localization of MEAGL except in 1 case
Absence of co-localization was considered to reflect the physiological condition of the specimen, based on similar staining in the normal adult adrenal medulla
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