Abstract
The in vivo oxidation of the norepinephrine metabolite 4-hydroxy-3-methoxyphenylglycol (HMPG) to 4-hydroxy-3-methoxymandelic acid was studied in man with two different doses of deuterium-labeled HMPG and a tracer dose of [14C]HMPG. HMPG oxidation appeared to be dose-dependent with an oxidation of 62-70% for doses below or equal to 2.2 .mu.mol. With the use of a capillary column coated with an optically active phase (Chirasil-Val) and gas chromatography mass-spectrometry the human urinary excretions of the 2 stereoisomers of deuterium-labeled HMPG (free + conjugates) were found to be equal.