"Total" acidic metabolites of catecholamines in urine as determined by hydrolysis with hydriodic acid and liquid chromatography: application to patients with neuroblastoma and melanoma.

Abstract

Abstract We describe a method for determining the "total" excretion of acidic metabolites of catecholamines by measuring 3,4-dihydroxyphenylacetic acid (DOPAC) formed by hydriodic acid hydrolysis of 4-hydroxy-3-methoxyphenylacetic acid (HVA), 4-hydroxy-3-methoxymandelic acid (VMA), and their conjugates. The DOPAC in the diluted hydrolysate is measured directly by liquid chromatography with electrochemical detection. Normal values, expressed in relation to excretion of creatinine, vary as a function of age. For healthy subjects, the mean DOPAC value after hydrolysis was 1.15 times that for unconjugated HVA, VMA, and DOPAC combined. Preliminary results for patients with neuroblastoma and melanoma indicate the potential usefulness of the method for diagnosis and prognosis of patients with neural crest tumors that produce dopa or catecholamines.