title: Cortisol secretion from adrenal adenomas discovered as incidentalomas is responsive to ACTH.
abstract: OBJECTIVE
  Adrenal adenomas discovered as incidentalomas may secrete cortisol and cause subclinical hypercortisolism. This cortisol secretion is considered to be autonomous. The aim was to investigate whether cortisol secretion by adenomas is responsive to ACTH.
  
  
  METHODS
  Descriptive retrospective study of consecutive patients.
  
  
  METHODS
  Eighty patients found to have adrenal incidentalomas during 2008 and 2009 at our hospital were examined, and 50 patients with a unilateral adenoma were included in the study.
  
  
  METHODS
  Cortisol and ACTH were measured at baseline and using 1-mg overnight dexamethasone suppression test (DST). The cortisol response to ACTH was calculated using the expression: (cortisolbasal -cortisolDST )/(ACTHbasal -ACTHDST ).
  
  
  RESULTS
  The patients were divided into three groups according to their basal ACTH: ≥3·0 pm (29 patients), 2·0-2·9 pm (9 patients) and <2·0 pm (12 patients). Cortisol at DST was similar in the three groups: 30, 46 and 43 nm (P = 0·10). The cortisol response to ACTH increased stepwise between the groups: 98, 172 and 249 nm/pm (P = 0·000, undetectable ACTH was set to 0 pm). Basal ACTH was negatively correlated with the size of the adenoma and positively correlated with the attenuation of the adenoma at unenhanced CT (P = 0·03 and P = 0·04, respectively).
  
  
  CONCLUSIONS
  Patients with adrenal adenomas and low basal ACTH show increased cortisol response to ACTH, and the adenomas seem to be the source of the increased cortisol secretion. The increased response to ACTH could be a pathogenic factor in metabolic complications of subclinical hypercortisolism. The cortisol response to ACTH may therefore be a useful measure of subclinical hypercortisolism.
authors.affiliation: Department of Internal Medicine, Helsingborg Hospital, Faculty of Medicine, Lund University, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Olsen
authors.forename: Li
authors.initials: L
authors.lastname: Olofsson
authors.forename: Mattias
authors.initials: M
authors.lastname: Mjöman
mesh_terms: D000236:Adenoma / Q000175:diagnosis / Q000378:metabolism; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000175:diagnosis / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010912:Pituitary-Adrenal Function Tests; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone