• Prolactin concentrations of 30 unmedicated psychiatric inpatients and 11 normal controls were measured at baseline and at 30 and 60 minutes after the administration of 10 mg of intramuscular methadone hydrochloride. Methadone raised the prolactin level at 60 minutes to more than twice the mean baseline level for the full subject sample. Patients with depressive disorders had lower mean basal prolactin levels than did the other subjects, and also manifested attenuated prolactin responses to methadone. Eight of 16 depressives had markedly blunted prolactin responses, a finding consistent with other studies reporting deficient responses in depression. These data are consistent with the hypothesis that the pathophysiology of depressive disorders involves dysfunctions in the anterior pituitary itself or in the hypothalamic neurotransmitter and neuromodulator systems (eg, endorphins) that regulate the secretion of prolactin and other neurohormones.
Judd LL, Risch SC, Parker DC, Janowsky DS, Segal DS, Huey LY. Blunted Prolactin ResponseA Neuroendocrine Abnormality Manifested by Depressed Patients. Arch Gen Psychiatry. 1982;39(12):1413-1416. doi:10.1001/archpsyc.1982.04290120045009