PROLACTIN AND TSH RESPONSES TO TRH AND TO HALORERIDOL IN SCHIZOPHRENIC-PATIENTS BEFORE AND AFTER TREATMENT

The prolactin (PRL) and the TSH responses to thyrotropin releasing hor mone (TRH, 0.4 mg i.v.) and to haloperidol (5 mg i.m.) were studied in II male schizophrenic patients in a drug-free state and after treatme nt with haloperidol, 60 mg daily. The PRL responses observed after i.m . haloperidol in the drug-free state, on average 35.4 ng/ml, were abol ished after treatment, indicating complete receptor blockade, while th e PRL responses to TRH were preserved, although moderately reduced (fr om 19.4 to 14.8 ng/ml on average). The TSH responses to TRH were unalt ered by the treatment (means 8.25 and 7.74 mIU/l). The results show th at the TSH and partially the PRL releasing actions of TRH are not medi ated via receptors that are effectively blocked by haloperidol.