Prolactin secretion in women with unipolar and bipolar depression.

Plasma prolactin levels and prolactin response to thyrotropin releasing hormone (TRH) were studied in 27 unipolar and 24 bipolar depressive female patients before and after tricyclic antidepressant treatment, as well as in 38 normal controls matched for age, sex, and menopausal status. Before antidepressant treatment, basal prolactin levels were significantly lower in both premenopausal and postmenopausal bipolar patients but only in postmenopausal unipolar patients when compared to controls. The prolactin response to TRH was significantly blunted in both unipolar and bipolar postmenopausal subjects but remained normal in all premenopausal (unipolar and bipolar) patients. These data suggest that prolactin pituitary function could be useful in the neuroendocrine study of depressive illness.