Blunted aldosterone response to dexamethasone in female patients with endogenous depression

(1) The dexamethasone suppression test (DST) was utilized to study the aldosterone (Aldo) response in patients with endogenous depression (ED). This adrenal steroid is believed to be regulated by CNS factors different from ACTH. (2) Six female patients (two pre- and four post-menopausal) and six female healthy controls (three pre-and three post-menopausal) were studied under equivalent conditions. Venous blood samples were taken at 0900 and 2300 hr before and at 0900, 1600 and 2300 hr after dexamethasone (2 mg p.o.) given at 2300 hr. In healthy controls, the median of plasma Aldo at 0900 hr before dexamethasone was lower than at 0900 hr after drug administration (p less than 0.01), while the opposite change occurred in the patients. The median of the controls at 0900 hr post-dexamethasone was 101 pg/ml, and that of the patients was 23 pg/ml (p less than 0.025). (3) According to these observations dexamethasone appears to have a stimulatory effect on 0900 hr plasma Aldo-levels, which are blunted in patients with ED. This finding possibly signifies disinhibited central dopaminergic function in ED. Whether dopamine acts directly on the adrenal gland or modulates Aldo secretion via Aldo-releasing factors different from ACTH remains unresolved. The neurotransmitter process which underlies Aldo regulation appears to be substantially altered in ED.