Pilot investigation of thyrotropin-releasing hormone-induced thyrotropin and prolactin release in anxious patients treated with diazepam.

Benzodiazepines have been reported to inhibit thyrotropin (TSH) and prolactin (PRL) secretion in response to stressful and pharmacologic stimuli in experimental animals. The current study investigates basal and thyrotropin-releasing hormone (TRH)-stimulated TSH and PRL release in anxious patients treated with diazepam. Six hospitalized patients having generalized anxiety or adjustment disorder with anxious mood (DSM III-R criteria) were treated during 1 week with diazepam (mean daily dose 33.3 mg). TRH testing was performed comparatively before and after 7 days of diazepam administration (with 250 micrograms protirelin and blood sampling at 15-min intervals over 60 min). Steady-state plasma levels of diazepam and its metabolite nordazepam (desmethyldiazepam) were determined by high-performance liquid chromatography. After 7 days of diazepam treatment, basal plasma levels of TSH and PRL were not affected compared with pretreatment values. Similarly, the time-course of TRH-induced TSH release was not modified by the treatment. By contrast, there was a trend to decrease in the TRH-induced PRL release, and the decrease in the PRL response to TRH on day 7 was significantly correlated with plasma nordazepam concentrations (rs = 0.943, p = 0.02). These preliminary results suggest that benzodiazepines, at therapeutic doses for the treatment of anxiety, may alter TRH-induced PRL release in humans.