EFFECTS OF ANTIDEPRESSANTS ON THYROID-STIMULATING HORMONE-RELEASE IN RATS UNDER ETHER STRESS

We found inhibitory effects of antidepressants (clomipramine, maprotyl ine, mianserin and zimelidine) and 5-hydroxytryptophan (5-HTP) on thyr oid stimulating hormone (TSH) release induced by ether stress in freel y moving rats. We confirmed that ether stress suppressed the plasma TS H levels after 30 min. We then injected intravenously 250 ng thyrotrop in releasing hormone (TRH), 0.1 mg/kg clomipramine, 2.5 mg/kg maprotyl ine, 2.5 mg/kg mianserin, 0.5 mg/kg zimelidine and 25 mg/kg 5-HTP simu ltaneously. These materials blocked the influences on plasma TSH level s by the ether stress. Serotonergic antidepressants (clomipramine, zim elidine) and 5-HTP (precursor of serotonin) had a higher potency again st the ether stress. These results suggest that antagonizing effects a gainst the ether stress may involve the serotonergic system in the pit uitary gland.