title: The function of the hypothalamic-pituitary-adrenal axis in Alzheimer's disease. Response to insulin hypoglycaemia.
abstract: BACKGROUND
  To investigate an association between HPA axis dysfunction, depression and cognitive impairment, we assessed subjects with mild Alzheimer's disease (AD).
  
  
  METHODS
  Sixteen non-depressed subjects with AD according to NINCDS/ADRDA criteria and 18 normal controls underwent the insulin hypoglycaemia (IH) test and the dexamethasone suppression test (DST).
  
  
  RESULTS
  The AD subjects showed a blunted response of adrenocorticotrophic hormone (ACTH) to IH compared with controls (P = 0.019). ACTH response (area under curve) correlated with a score for cognitive ability (CAMCOG) (r = 0.64, P < 0.01). AD subjects had a shorter time to peak cortisol level than controls (P = 0.004), although total cortisol response was normal.
  
  
  CONCLUSIONS
  The AD subjects show evidence of adrenal hyper-responsiveness and normal immediate (rate-sensitive) glucocorticoid feedback. An association between HPA axis dysfunction and organic brain pathology in AD subjects may be mediated by cell loss in the hippocampus.
authors.affiliation: University of Melbourne Department of Psychiatry, Australia.
authors.forename: J T
authors.initials: JT
authors.lastname: O'Brien
authors.forename: I
authors.initials: I
authors.lastname: Schweitzer
authors.forename: D
authors.initials: D
authors.lastname: Ames
authors.forename: M
authors.initials: M
authors.lastname: Mastwyk
authors.forename: P
authors.initials: P
authors.lastname: Colman
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D003907:Dexamethasone; D003937:Diagnosis, Differential; D005246:Feedback / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007003:Hypoglycemia / Q000139:chemically induced / Q000503:physiopathology*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007328:Insulin; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010913:Pituitary-Adrenal System / Q000503:physiopathology*
chemical_list: D007328:Insulin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone