Effects of antidepressant treatment on thyrotropin-releasing hormone stimulation, growth hormone response to L-DOPA, and dexamethasone suppression tests in major depressive patients.

Dexamethasone suppression (DST), thyroid-stimulating hormone (TSH) and prolactin (PRL) responses to thyrotropin-releasing hormone (TRH) and growth hormone (GH) response to L-DOPA tests were evaluated in 19 depressed inpatients before the commencement of the antidepressant treatment and after the clinical response to examine: (i) the functional relationships among the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axis and dopaminergic system in depression, (ii) any alterations in these hormonal functions with the antidepressant treatment. TSH responses to TRH showed a tendency to increase from pre- to posttreatment period, while TRH-induced PRL and L-DOPA-induced GH responses did not change with treatment in depressed patients who responded to the treatment. Females showed significantly higher TSH and PRL responses to TRH compared to males. No interconnections were found among the responses in DST, TRH stimulation test and L-DOPA-induced GH test in the patients. The results do not support the interrelations between the abnormalities in the HPT and HPA axes and central dopaminergic activity in depression.