the proportion of total catecholamines existing in the free form was 78 +/- 4 % ( mean +/- se ) for norepinephrine , 52 +/- 5 % for epinephrine , and 50 +/- 10 % for dopamine , which was considerably higher than for plasma .
C0007412
total catecholamines
C0028351
norepinephrine