METABOLISM OF 3,4-DIHYDROXYPHENYLACETIC ACID (DOPAC) IN HUMAN

Five subjects were infused i.v. with 75 μC of 3,4-dihydroxyphenylacetic acid-214C(DOPAC) and urine collected at various intervals for 24 hr. The radioactive metabolic products in the urine were separated and identified. The results indicate that DOPAC is rapidly O-methylated to 3-methoxy-4-hydroxyphenylacetic acid (HVA). Within 24 hr after an i.v. infusion of DOPAC-2-14C 40 per cent of the radioactivity was recovered in the urine as HVA. Whereas HVA was the principal metabolic product, approximately 5 per cent of the DOPAC was metabolized to the conjugate of HVA. 3,4-Dihydroxybenzoic acid (DOBA) and trace amounts of vanillic acid were found, plus several unidentified metabolites. © 1969.