LOCALIZATION OF DOPAMINE‐β‐OXIDASE IN BRAIN

THE sympathetic hormone norepinephrine has been shown to be derived from tyrosine and it is generally recognized that the immediate precursor is 3 :4dihydroxyphenylethylamine (dopamine). Conversion of the latter compound to norepinephrine in isolated peripheral tissues has been demonstrated many times. The presence of both dopamine and norepinephrine in the central nervous system suggested that this conversion also takes place in brain. The data presented in this report indicate that not only does brdn convert dopamine to norepinephrine but that the enzyme responsible for this conversion, dopamine-8-oxidase, is localized in those areas of the brain which are richest in norepinephrine and other catalysts and intermediates involved in its synthesis.