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PLASMA DOPAMINE‐BETA‐HYDROXYLASE ACTIVITY IN PHAEOCHROMOCYTOMA
Author(s) -
STONE RICHARD A.,
LILLEY JOHN J.,
GOLDEN JOEL
Publication year - 1976
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1976.tb02830.x
Subject(s) - catecholamine , exocytosis , endocrinology , medicine , dopamine , secretion , chemistry
Plasma dopamine‐beta‐hydroxylase (DßH) activity, a marker of catecholamine secretion that occurs via exocytosis, was determined preoperatively in eight patients with phaeochromocytoma. Despite very elevated urinary catecholamine concentrations, mean plasma DßH activity was 32.6±3 u/1 and was not significantly different from apparently healthy subjects. Seven days after surgery, one subject exhibited a 60% postoperative decrease of enzyme activity. These results suggest that diffusion across plasma membranes is the predominant mechanism of catecholamine release from phaeochromocytomas. The postoperative change in one patient suggests tumour heterogeneity and that exocytosis may contribute to the process of catecholamine release in some patients.