title: Associations between neuroendocrine responses to the Insulin Tolerance Test and patient characteristics in chronic fatigue syndrome.
abstract: OBJECTIVE
  Subtle dysregulations of the hypothalamic-pituitary-adrenal (HPA) axis have been proposed as an underlying pathophysiological mechanism in chronic fatigue syndrome (CFS). This study attempted to assess the relationship between patient characteristics and HPA axis functioning using a neuroendocrine challenge test.
  
  
  METHODS
  A test battery designed to assess different dimensions of CFS was given to 18 CFS patients and 17 controls. To evaluate the integrity of the HPA axis, the Insulin Tolerance Test (ITT), a centrally acting neuroendocrine challenge test, was performed on patients and controls. ACTH, salivary free cortisol and total plasma cortisol levels were assessed as a measure of the HPA axis stress response. Correlations of patient characteristics were calculated with integrated responses for all endocrine parameters.
  
  
  RESULTS
  CFS patients had a significantly reduced area under the ACTH response curve (AUC) in the ITT. The AUC was significantly associated with the duration of CFS symptoms (r = -.592, P = .005) and the severity of fatigue symptomatology (r = -.41, P = .045). In addition, duration of CFS was correlated with the severity of fatigue symptoms (r = .38, P = .045). Similar associations were not observed for cortisol parameters.
  
  
  CONCLUSIONS
  It has been postulated that neuroendocrine dysregulations observed in CFS are of an acquired nature. The results of a strong association between the integrated ACTH response and the duration of CFS emphasizes the need to consider factors known to be risk factors for the chronicity of CFS symptoms, such as profound inactivity, deconditioning and sleep abnormalities, as possible candidates for secondary causes of neuroendocrine dysregulations in CFS.
authors.affiliation: Center for Psychobiological and Psychosomatic Research, University of Trier, Germany. jgaab@psychologie.unizh.ch
authors.forename: Jens
authors.initials: J
authors.lastname: Gaab
authors.forename: Veronika
authors.initials: V
authors.lastname: Engert
authors.forename: Vera
authors.initials: V
authors.lastname: Heitz
authors.forename: Tanja
authors.initials: T
authors.lastname: Schad
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Schürmeyer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ehlert
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000328:Adult; D001007:Anxiety / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D015673:Fatigue Syndrome, Chronic / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism* / Q000503:physiopathology*; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000378:metabolism* / Q000503:physiopathology*; D012720:Severity of Illness Index
chemical_list: D007328:Insulin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone