To determine if corticotroph nonsuppression, as reflected by β-endorphin nonsuppression, occurs before cortisol nonsuppression (defined as a cortisol level of >140 nmol/L) when examining multiple time points in a day.
The General Medical Clinical Research Center and Inpatient Depression Research Unit, Ann Arbor, Mich.
Multiple blood samples were obtained through an intravenous catheter around the time points of 8 AM, noon, and 4 PM and assayed for β-endorphin and cortisol.
Patients meeting Research Diagnostic Criteria for the diagnosis of major depressive disorder, primary and simple. A total of 73 subjects, both inpatients and outpatients, were studied.
Samples were obtained both at baseline and 1 day after administration of 1 mg of dexamethasone at 11:30 PM.
Measurements and Results:
Overall 39 patients (53%) demonstrated β-endorphin nonsuppression after administration of dexamethasone at any of the three time points, while only eight patients (11%) demonstrated cortisol nonsuppression at any of these time points. Cortisol nonsuppression, but not β-endorphin nonsuppression, was associated with lower concentrations of dexamethasone in plasma. Baseline cortisol and menopausal status were significantly associated with β-endorphin nonsuppression in women.
Young EA, Kotun J, Haskett RF, Grunhaus L, Greden JF, Watson SJ, Akil H. Dissociation Between Pituitary and Adrenal Suppression to Dexamethasone in Depression. Arch Gen Psychiatry. 1993;50(5):395-403. doi:10.1001/archpsyc.1993.01820170073010