Neuroendocrine perturbations in fibromyalgia and chronic fatigue syndrome

A large body of data from a number of different laboratories worldwide has demonstrated a general tendency for reduced adrenocortical responsiveness i n Chronic Fatigue Syndrome (CFS). It is still not clear if this is secondar y to abnormalities leading to decreased activity of corticotropin-releasing hormone (CRH)- or arginine vasopressin (AVP)-producing hypothalamic neuron s. primary hypofunction of the CRH neurons has been described on the basis of genetic and environmental influences. Ether pathways could secondarily i nfluence hypothalamic-pituitary-adrenal (PIPA) axis activity, however. For example, serotonergic and noradrenergic input acts to stimulate HPA axis ac tivity Deficient serotonergic activity in CFS has been suggested by some of the studies as reviewed here. In addition, hypofunction of sympathetic ner vous system function has been described and could contribute to abnormaliti es of central components of the HPA axis.