the involvement of a typical alpha-adrenergic mechanism in the control of release of acth , beta-endorphin and related peptides in rat anterior pituitary gland is indicated by the following order of potency of a series of catecholaminergic agents ( ed50 values ) : ( - ) epinephrine ( 20 nm ) greater than ( - ) norepinephrine ( 90 nm ) greater than phenylephrine ( 400 nm ) greater than isoproterenol ( 6000 nm ) .
C0014563
epinephrine
C0028351
norepinephrine