Augmented pituitary corticotropin response to a threshold dosage of human corticotropin-releasing hormone in depressives pretreated with metyrapone.

We studied pituitary corticotropin response to exogenous corticotropin-releasing hormone infusion and attempted to control for the confounding effect of variable serum cortisol levels between depressed and control subjects. If metyrapone was given during the time of day when hypothalamic pituitary adrenal activity was otherwise low, the relative increase in the corticotropin concentration was small. Pituitary response to exogenous corticotropin-releasing hormone can be defined under conditions in which the amount of glucocorticoid-mediated negative feedback present at the level of the pituitary gland is equal in all subjects.