this activity was stimulated ( in the presence as well as in the absence of added gtp ) by d , l-isoproterenol , l-epinephrine and l-norepinephrine , the relative potency of these agonists being compatible with the existence of beta-adrenoceptors of the beta2 subtype .
C0014563
epinephrine
C0028351
l-norepinephrine