Basal and stimulated hypothalamic-pituitary-adrenal axis activity in patients with functional gastrointestinal disorders and healthy controls

Objective: The aim of this study was to investigate alterations of pituitary-adrenal activity under both stimulated and unstimulated conditions in patients with functional gastrointestinal disorders. Methods: Thirty subjects who fulfilled the Rome Diagnostic Criteria for either irritable bowel syndrome or nonulcer dyspepsia and 24 healthy controls took part in the study. Free salivary morning cortisol and diurnal cortisol profiles were obtained for all subjects. On a second day, a low-dose dexamethasone suppression test was applied. Additionally, in all subjects a corticotropin-re leasing hormone (CRH) challenge test was performed. Results: The results show attenuated unstimulated cortisol levels in patients compared with controls. After CRH challenge, blunted adrenocorticotropic hormone and cortisol responses were observed. These findings suggest lower pituitary and adrenocortical activity in patients with functional gastrointestinal disorders. Conclusion: The observed pituitary-adrenal reactivity in these patients is discussed as a possible consequence of lower adrenocortical activity, possibly resulting in a disinhibition of CRH in the brain.