Plasma 3-methoxy-4-hydroxyphenethyleneglycol in pheochromocytoma.

Plasma concentrations of the major brain metabolite of norepinephrine, 3-methoxy-4-hydroxyphenethyleneglycol (MHPG), were assayed in patients with essential, renovascular hypertension, pheochromocytoma and in controls. The concentration of MHPG was significantly elevated in patients suffering from pheochromocytoma and was found to be related to tumor size.