Abstract
Phenylpyruvic acid, phenyllactic acid and phenylacetic acid inhibit beef adrenal medulla DOPA decarboxylase. Phenylalanine had no effect. These data suggest an explanation for low epinephrine plasma levels observed in patients afflicted with phenylpyruvic oligophrenia in that these aromatic acids, which accumulate as a result of the biochemical lesion, may inhibit synthesis of epinephrine in the adrenal gland.