Deficiency of phenylethanolamine N-methyltransferase in norepinephrine-producing pheochromocytoma

Noriko Kimura, Akira Togo, Takako Sugimoto, Koji Nata, Hiroshi Okamoto, Ikuko Nagatsu, Hiroshi Nagura

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5 Citations (Scopus)


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 (TH) 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.

Original languageEnglish
Pages (from-to)131-136
Number of pages6
JournalEndocrine Pathology
Issue number2
Publication statusPublished - 1996 May


  • Epinephrine (E)
  • In situ hybridization (ISH)
  • Norepinephrine (NE)
  • Northern blot hybridization
  • Phenylethanolamine N-methyltransferase (PNMT)
  • Pheochromocytoma


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