The effect of psychotropic drugs on the TSH-response to thyroliberin (TRH)

The effect of chlorpromazine (CPZ), thioridazine (TR), L-dopa, fusaric acid (FA), pimozide (PZ) and propranolol (P) in the i.v. thyrotropin-releasing hormone (TRH) stimulation test was studied in 75 subjects. It was found that chronic treatment with CPZ, TR and L-dopa inhibits the response to TRH. FA may to some extent counteract the effect of L-dopa. The results indicate that the response of the pituitary to TRH as regards the secretion of TSH is mainly regulated by norepinephrinergic alpha-receptors.