A RE-EVALUATION OF ACETYLCHOLINE, ADRENALINE, NOR-ADRENALINE AND HISTAMINE AS POSSIBLE MEDIATORS OF THE PITUITARY ADRENOCORTICOTROPHIC ACTIVATION BY STRESS1

THE use of specific pharmacologic antagonists to study the participation of the various autonomic mediators in the activation of the anterior lobe of the pituitary during stress has been found impractical by many investigators owing to the strong ACTH-releasing effects of these substances when administered alone or concurrently with the mediator investigated. Thus, no conclusive results have been reported on the role of endogenous epinephrine in the ACTH-release mechanism (August and Gubner, 1949; Seifter et al., 1949; Paschkis et al., 1950; Ronzoni and Reichlin, 1950; Tepperman and Tepperman, 1950; Gershberg et al., 1950; Fortier, 1951a; Sawyer, 1952) nor of acetylcholine (Dordoni and Fortier, 1950) or histamine (Fortier and Guillemin, 1950; Tepperman et al., 1951). A new approach to this problem was made possible when it was shown that by “adapting” (Serve, 1946) the animals to a pharmacological agent by repeated injections it became possible to dissociate its specific pharmacodynamic effects from its n...