Chapter 34 Role of aldehyde oxidase in biogenic amine metabolism

Abstract

Publisher Summary This chapter discusses the role of aldehyde oxidase in biogenic amine metabolism. It shows that both homovanillyl aldehyde and 5-hydroxy-3-indoleacetaldehyde are substrates for guinea pig liver aldehyde oxidase. The results obtained with both in vivo and in vitro inhibitors indicate that aldehyde oxidase plays a major role in homovanillic (HV) and 5-hydroxytryptamine (5-HT) metabolism in guinea pig liver. In view of the similarity between the guinea pig and human liver aldehyde oxidase, it is likely that human hepatic aldehyde oxidase may also be important in biogenic amine metabolism. The urinary metabolites of 5-HT in have been examined in oriental subjects, but no correlation was found between 5-hydroxyindoleacetic acid (5-HIAA) production and mitochondrial aldehyde dehydrogenase genotype. It was suggested that cytosolic aldehyde dehydrogenase could oxidize physiological concentrations of 5-hydroxyindoleacetaldehyde when the mitochondrial isozyme is absent. However, this oxidation could equally well be carried out by aldehyde oxidase. Although peripheral plasma levels of HV acid—the deaminated and O-methylated metabolite of dopamine—are often used as an indicator of central dopaminergic activity. Lambert have shown that HVA is produced locally, perhaps from circulating DOPA.