Catecholamine synthesizing enzymes in 70 cases of functioning and non-functioning phaeochromocytoma and extra-adrenal paraganglioma.
Immunohistochemical localization of the catecholamine synthesizing enzymes, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT), was investigated in 70 cases of functioning and non-functioning phaeochromocytomas comprising 52 of adrenal and 18 of extra-adrenal origin. Of 59 functioning tumours, 30 were mixed epinephrine and norepinephrine-producing (mixed type) and 29 were norepinephrine-producing tumours. TH, AADC and DBH were detected in all functioning phaeochromocytomas, but PNMT was limited to the mixed-type phaeochromocytomas. Non-functioning phaeochromocytomas were divided into two groups, comprising a complete type, which induced neither elevated plasma catecholamines nor their metabolites in urine, and an incomplete type which exhibited no elevated plasma catecholamines, but showed a slightly high urinary vanillylmandelic acid level. In the non-functioning complete-type tumours, immunoreactive TH was negative, but the incomplete tumours of the adrenal medulla had all four enzymes, and corresponded to a mixed-type phaeochromocytoma. AADC and DBH were present universally in all functioning and non-functioning tumours, including TH-negative tumours. TH is a rate-limiting enzyme of catecholamine biosynthesis and deficiency of TH is an important feature of extra-adrenal non-functioning phaeochromocytomas.
Department of Pathology, Tohoku University School of Medicine, Sendai, Japan.
N
N
Kimura
Y
Y
Miura
I
I
Nagatsu
H
H
Nagura
D000310:Adrenal Gland Neoplasms / Q000201:enzymology* / Q000473:pathology; D000328:Adult; D000368:Aged; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000032:analysis*; D002395:Catecholamines / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010235:Paraganglioma / Q000201:enzymology* / Q000473:pathology; D010625:Phenylethanolamine N-Methyltransferase / Q000032:analysis*; D010673:Pheochromocytoma / Q000201:enzymology* / Q000473:pathology; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis*
D002395:Catecholamines; D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase; D001142:Aromatic-L-Amino-Acid Decarboxylases