Circulating Dopamine-?-Hydroxylase (D?h) and Catecholamines in a Paediatric Phaeochromocytoma

Abstract

1. Circulating catecholamines and dopamine-beta-hydroxylase (DbetaH) have been studied in a child with bilateral phaeochromocytoma. 2. Venous catheterization showed a great increase in catecholamine efflux from the left adrenal vein while DbetaH activity in the latter was only slightly elevated. 3. Circulating catecholamines fluctated greatly while DbetaH activity decreased gradually during the removal of the tumours. 4. Post-operatively, circulating catecholamines declined to normal values while DbetaH activity returned to pre-operative levels. 5. It is concluded that these tumours released circulating catecholamines independent of an exocytotic secretion of DbetaH and that the circulating DbetaH reflected the activity of the sympathetic nervous system.

A paroxysmally secreting phaeochromocytoma: Biochemical and clinical aspects

“…Winkler and Smith suggested two modes of release of catecholamines from not innervated tumor cells finally involving the diffusion out of the cell [34]. This hypothesis was supported by several investigations demonstrating that DBH activity in plasma did not decrease after the removal of the tumor [8,10,13,32]. A postoperative decrease of DBH activity in plasma however has been found in several patients, indicating an important role of exocytosis in catecholamine secretion from phaeochromocytoma [1,2,16,17].…”