epinephrine ( 70 microm ) , norepinephrine ( 50 microm ) , and dopamine ( 25 microm ) were unable to stimulate acrosome reactions even at 30 min under the same conditions , even though previous studies had demonstrated stimulation by these catecholamines at the same concentrations when present from the start of the capacitation time course .
C0014563
epinephrine
C0028351
norepinephrine