we infused isoproterenol ( iso ) intravenously into 23 subjects ( 3.5 , 7 , 14 , and 35 ng/kg/min for 20 minutes at each dose ) and measured venous plasma concentrations of iso and the circulatory and plasma norepinephrine ( ne ) and epinephrine ( e ) responses .
C0028351
norepinephrine
C0014563
epinephrine