specific activities were determined by high-performance liquid chromatography for each of the three o-methylated metabolites of norepinephrine in the urine samples , and were then used to calculate the fraction of 4-hydroxy-3-methoxymandelic acid ( vma ) formed from 4-hydroxy-3-methoxyphenylglycol ( mhpg ) and from normetanephrine .
C0028351
norepinephrine
C0028385
normetanephrine