Catecholamine Metabolism in Neuroblastoma: Kinetics of Conversion of3H-3-methoxy-4-hydroxyphenylglycol to3H-3-methoxy-4-hydroxymandelic Acid

Abstract

Previous studies of the metabolic activity of neuroblastoma tumor in tissue culture have revealed that added ³H-norepinephrine (³H-NE) is partially converted to ³H-3-methoxy-4-hydroxyphenylglycol (³H-MHPG), but not to 3-methoxy-4-hydroxymandelic acid. In addition, the in vivo conversion of ³H-MHPG to ³H-VMA has been described. This report presents quantitative information on the in vivo conversion of ³H-MHPG to ³H-VMA (27%) based on the results of assay of urinary ³H-VMA following the iv injection of ³H-VMA itself, and following iv ³H-MHPG. In addition, this patient was normotensive and his tumor converted ³H-NE to ³H-MHPG in tissue culture. These findings provide quantitative information on the in vivo conversion of MHPG to VMA in a patient with neuroblastoma and suggest that assay of urinary MHPG, after hydrolysis of the conjugates, may be of considerable value in the diagnosis of patients with neuroblastoma.