Figure 85.12. Synthetic and metabolic pathways for the catecholamines, norepinephrine and epinephrine, which are stored and secreted by chromaffin cells and pheochromocytomas.

Figure 85.12

Synthetic and metabolic pathways for the catecholamines, norepinephrine and epinephrine, which are stored and secreted by chromaffin cells and pheochromocytomas. Curved arrows, physiologic agonist—receptor interaction. Boxed arrows, competitive antagonism at the rate-limiting step of synthesis or at receptor sites by therapeutic agents (see text). TH = trosine hydroxylase; DDC = dopa decarboxylase; PBH = phenylamine-β-hydroxylase; PMT = phenylethanolamine-N-mehtyltransferase; COMT = catechol-O-methyltransferase; MAO = monoamine oxidase.

From: Chapter 85, Neoplasms of the Neuroendocrine System and Neoplasms of the Gastroenteropancreatic Endocrine System

Cover of Holland-Frei Cancer Medicine
Holland-Frei Cancer Medicine. 5th edition.
Bast RC Jr, Kufe DW, Pollock RE, et al., editors.
Hamilton (ON): BC Decker; 2000.
© 2000, BC Decker Inc.

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