(Des-tyrosine1)-gamma-endorphin in schizophrenia: clinical, biochemical, and hormonal aspects

The neuropeptide (des-tyrosine1)-gamma-endorphin (DT gamma E; beta-LPH 62-77) was given to 10 schizophrenic patients who had been free of neuroleptic medication for at least 3 weeks. DT gamma E was injected intramuscularly in a dose of 1 mg daily for 10 days following a double-blind placebo-controlled crossover design. In 4 of the 10 patients a pronounced antipsychotic effect was observed; in 3 a temporary or slight reduction of psychotic symptoms occurred; and in 3 no response was noted. DT gamma E led to decreased plasma levels of prolactin and in some patients to increased concentrations of homovanillic acid in cerebrospinal fluid (CSF). Neither plasma levels of growth hormone and cortisol nor CSF concentrations of 5-hydroxyindoleacetic acid were affected by DT gamma E. These data confirm that DT gamma E has antipsychotic properties in a number of schizophrenic patients and suggest an interaction between DT gamma E and central dopaminergic systems.