The Destruction of Glucagon, Adrenocorticotropin and Somatotropin by Human Blood Plasma*

Human blood contains an inactive proteolytic enzyme, plasminogen, which may be converted in vitro to its active form, plasmin, either spon- taneously or by the addition of various agents (1). A similar activation is believed to occur in vivo after exposure to a variety of noxious circumstances (2-6). Since plasmin catalyzes the hydrolysis of corticotropin A (7), it is pos- sible that circumstances which induce the acti- vation of plasmin will result also in an increase in the rate of destruction of adrenocorticotropic (ACTH) and other polypeptide hormones.