Plasma ACTH responses to cortisol infusion are similar in patients with primary hypoadrenalism and patients studied some years after bilateral adrenalectomy for Cushing's syndrome.
It has been suggested that the first-phase feedback of steroid feedback on ACTH secretion is abnormal in Cushing's disease patients studied after adrenalectomies. We have performed hydrocortisone infusions (100 mg over 2 h) in 15 patients who had previously undergone bilateral adrenalectomy for Cushing's disease. None had had any pituitary-directed therapy and none had a pituitary macroadenoma. Their responses were compared with a group of seven hypoadrenal patients. A significant rise in serum cortisol was observed between 5 and 10 min in both groups. The first significant fall in ACTH occurred between 30 and 45 min in both groups. There was no abnormality of first-phase feedback in the Cushing's group and our results do not therefore support previous speculation that such an abnormality provides evidence for a higher central nervous system (CNS) aetiology of Cushing's disease.
Atkinson
A B
AB
Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, UK.
Beacom
R
R
Kennedy
A L
AL
Hadden
D R
DR
Sheridan
B
B
D000309:Adrenal Insufficiency / Q000097:blood*; D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D003480:Cushing Syndrome / Q000097:blood* / Q000601:surgery; D005246:Feedback; D006801:Humans; D006854:Hydrocortisone; D011863:Radioimmunoassay; D013997:Time Factors
D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone