The influence of 4-week treatment with sertraline on the combined T3/TRH test in depressed patients.

In the present study, the influence of a 4-week treatment with sertraline on the regulation of hypothalamic-pituitary-thyroid (HPT) axis activity in depression was investigated, in particular the impact of sertraline on the thyroid receptor (TR)-mediated negative feedback control as measured by the combined T3/TRH test. In 20 drug-free patients (8 men, 12 women) suffering from a major depressive episode according to DSM-IV criteria the single TRH-stimulation test (administration of 200 microg TRH at 09:00h) was carried out followed by a combined T3/TRH test (pre-treatment with 40 microg 3,5,3'-triiodothyronine [T3] the night before; administration of 200 microg TRH at 09:00h the next day). After 4 weeks of treatment with sertraline at a standard dosage of 50 mg/day, both the single TRH test and the combined T3/TRH test were repeated in the depressed patients. Using repeated-measures ANOVA for statistical analysis, antidepressant therapy with sertraline did not have any significant impact on the TRH-induced TSH and prolactin stimulation (deltaTSH, deltaPRL) during the single TRH test nor during the combined T3/TRH test, neither in responders (n = 10) nor in non-responders (n = 10). Moreover, the percentage suppression of TRH-induced TSH stimulation (deltaTSH) after pre-treatment with 40 microg T3 was comparable before (-61.07%) and after the 4-week treatment with sertraline (-58.92%). Apparently, the therapeutic efficacy of antidepressants such as sertraline is not related to the regulation of HPT axis activity in depressed patients.