Excretion of metabolites of biogenic amines in patients with irradiated brain tumours.

The metabolities of biogenic amines were determined in the 24-hour urine samples of patients submitted to surgical removal of a malignant brain tumour and subsequently to telecobalt therapy of the corresponding head region. A significant increase in the excretion of 5-hydroxyindoleacetic acid (5-HIAA), vanillinmandelic acid (VMA) as well as of free 3-methoxy-4-hydroxy-phenylglycol (MHPG) during the period of irradiation was found. This increase is presumably the result of radiation induced release of their parent amines from the brain; in the case of VMA the secondary response of the peripheral sympathetic system might occur.