CHANGES IN TSH RESPONSES TO TRH AND PLASMA BIOGENIC-AMINE METABOLITESDURING TREATMENT OF DEPRESSED-PATIENTS WITH MOCLOBEMIDE

The TSH responses to TRH and the plasma levels of the main metabolites of noradrenaline (methoxyhydroxyphenylglycol, MHPG), of dopamine (hom ovanillic acid, HVA), and of serotonin (5-hydroxyindoleacetic acid, 5H IAA), were assessed in 16 depressed patients before and after four wee ks treatment with the reversible MAO-A inhibitor moclobemide. The diff erences in the TSH responses after treatment, were correlated to the c hanges in the biogenic amine metabolites, using multiple regression an alysis. An association of the changes in TSH responses to the reductio n in plasma MHPG, and not to the changes in HVA or 5HIAA was revealed. The results show that increased availability of noradrenaline, caused by inhibition of its degradation, enhances the TSH response to TRH, w hile dopamine and serotonin do not seem to participate much in this ev ent.