NALOXONE-MEDIATED ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS IN CHRONIC-FATIGUE-SYNDROME

Background. Opioidergic pathways have an inhibitory regulatory influen ce on the hypothalamic-pituitary-adrenal axis (HPA) in man. Previous s tudies have suggested impairment of pituitary-adrenal activation in ch ronic fatigue syndrome (CFS). We, therefore, decided to investigate th e extent of opioid inhibition of HPA activity in CFS as a possible exp lanation for the reputed HPA hypofunctioning in patients with CFS. Met hod. Thirteen patients with CFS, diagnosed according to CDC criteria, were compared with thirteen healthy subjects. Adrenocorticotropin (ACT H) and cortisol (CORT) responses were measured following the administr ation of the opiate antagonist naloxone. Results. Baseline ACTH and co rtisol levels did not differ between the two groups. The release of AC TH (but not cortisol) was significantly blunted in the CFS subjects co mpared with controls. Conclusions. Naloxone mediated activation of the HPA is attenuated in CFS. Excessive opioid inhibition of the HPA is t hus an unlikely explanation for the HPA dysregulation in this disorder .