The role of the pituitary-adrenocortical axis in reflex responses of the adrenal medulla of the dog.

1. The release of catecholamines from the adrenal medulla, in response to carotid body hypoxia, may outlast the stimulus by more than 30 min. 2. After denervation of the adrenal gland the immediate release of catecholamines in response to carotid hypoxia is abolished, but the prolonged release remains. 3. The prolonged release of catecholamines is abolished by cycloheximide. 4. Both corticotrophin in vivo and hydrocortisone in the isolated perfused adrenal gland release adrenomedullary catecholamines. 5. It is concluded that a component of the response of the adrenal medulla to carotid body hypoxia is mediated by corticotrophin and corticosteroid release.