Deficiency of Phenylethanolamine N-Methyltransferase in Norepinephrine-Producing Pheochromocytoma.
Endocr Pathol
; 7(2): 131-136, 1996.
Article
de En
| MEDLINE
| ID: mdl-12114640
ABSTRACT
Pheochromocytoma is a catecholamine (CA)-producing tumor that is classified into two types the norepinephrine (NE) and the mixed NE and epinephrine type (E-type) from plasma CA levels. Phenylethanolamine N-methyltransferase (PNMT) is the terminal enzyme in CA synthesis; it catalyzes the synthesis of E from NE. It is not known whether the absence of immunoreactive PNMT is paralleled by a lack of PNMT mRNA. The mRNA of tyrosine hydroxylase (TI-I) and PNMT in seven pheochromocytomas, five NE-type and two E-type tumors, were examined by Northern blot analysis and in situ hybridization (ISH) technique. TH mRNA was detected in all tumors but PNMT mRNA was limited only to the E-type tumors. In addition to our previous immunohistochemical study of 70 pheochromocytomas and paragangliomas in which all pheochromocytomas had cells immunoreactive to TH, but PNMT was expressed only in E-type, we concluded that NE-type pheochromocytoma lacks PNMT both at the mRNA and protein levels, resulting in an inability to produce E. The essential difference between NE-type and E-type pheochromocytoma is that the NE-type lacks PNMT.
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Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Endocr Pathol
Sujet du journal:
ENDOCRINOLOGIA
/
PATOLOGIA
Année:
1996
Type de document:
Article