Normal opioid tone and hypothalamic-pituitary-adrenal axis function in chronic fatigue syndrome despite marked functional impairment.
OBJECTIVE
To determine whether the functional impairment seen in chronic fatigue syndrome (CFS) is associated with reduced levels of central opioids and/or deficiency of the hypothalamic-pituitary-adrenal (HPA) axis.


METHODS
Single-blinded case-control study measuring functional and psychological status, basal hormonal parameters and ACTH/cortisol response to naloxone and ovine corticotrophin-releasing hormone (oCRH) vs. placebo in people with CFS and healthy controls.


METHODS
Twelve people with CFS and 11 age-matched controls.


METHODS
Hormonal parameters: basal levels of 09:00 h plasma cortisol, dehydroepiandrosterone sulfate (DHEAS) and IGF-1. 24-h urinary free cortisol. Plasma ACTH and cortisol response to naloxone 125 microg/kg, oCRH 1 microg/kg and placebo (normal saline). Psychological parameters: SF-36, Hamilton Depression Score, Hospital Anxiety and Depression Scale and Fatigue Scale.


RESULTS
There were highly significant differences between the CFS subjects and the controls with respect to the measures of fatigue and physical functioning. However, there were no differences in basal levels of 09:00 h cortisol (367 +/- 37 vs. 331 +/- 39 nmol/l, P = 0.51), DHEAS (4.2 +/- 0.6 vs. 4.0 +/- 0.5 micromol/l, P = 0.81), 24-h urinary free cortisol (182 +/- 27 vs. 178 +/- 21 nmol/24 h, P = 0.91) or IGF-1 (145 +/- 19 vs. 130 +/- 11 microg/l, P = 0.52) between the CFS group and controls, respectively. There was also no difference between the groups with respect to the ACTH and cortisol response to either oCRH or naloxone.


CONCLUSIONS
Our data do not support an aetiological role for deficiency in central opioids or the HPA axis in the symptoms of CFS.
Inder
Warrick J
WJ
Department of Endocrinology, Christchurch Hospital, and Department of Psychological Medicine, Christchurch School of Medicine, Christchurch, New Zealand. winder@medstv.unimelb.edu.au
Prickett
Timothy C R
TC
Mulder
Roger T
RT
D000324:Adrenocorticotropic Hormone / Q000097:blood; D016022:Case-Control Studies; D003346:Corticotropin-Releasing Hormone; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D015673:Fatigue Syndrome, Chronic / Q000378:metabolism / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D009270:Naloxone; D018847:Opioid Peptides / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D011581:Psychological Tests; D016037:Single-Blind Method
D018847:Opioid Peptides; D009270:Naloxone; D019314:Dehydroepiandrosterone Sulfate; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone