Atrial Natriuretic Hormone Decreases Endocrine Response to a Combined Dexamethasone–Corticotropin-Releasing Hormone Test

Background: An escape from the dexamethasone-induced suppression of pituitary–adrenocortical activity can be provoked by corticotropin-releasing hormone (CRH) in depressed patients, but not in healthy controls. One important antagonist of the CRH-stimulated secretion of corticotropin (ACTH) and cortisol is atrial natriuretic hormone (ANH). Methods: To study a potential role of ANH in the dexamethasone-CRH test, we investigated 7 healthy men who did not suppress cortisol below 40 ng/mL after they had received 0.5 mg dexamethasone the evening before. Results: We found 1) that the CRH-stimulated ACTH and cortisol secretion was significantly reduced by the administration of ANH in comparison to saline; and 2) that there was an increased pituitary–adrenocortical ratio. Conclusions: Our results support the view that ANH may also be involved in the frequently observed nonsuppression after dexamethasone during depression.