[Neuroendocrine effects of benzodiazepines]

After presenting some general aspects of psychoneuroendocrinology, pharmaco-endocrinology and benzodiazepine receptor molecular pharmacology, the author reviews the neuro-endocrine effects of the benzodiazepines both in experimental animals and in humans. While benzodiazepines produce inconsistent effects on basal hormone secretion, they have potent effects on inhibition of ACTH, cortisol, TSH and prolactin secretion in response to stressful and pharmacological stimuli. Acute diazepam administration causes stimulation of GH secretion, but patients taking this drug regularly over periods of years have an impaired GH response or no response at all (tolerance). The mechanisms of action by which the benzodiazepines produce their effects on neuroendocrine functions are complex. The BZD may act at GABA-coupled BZD receptors in hypothalamus, or other brain regions to potentiate the effects of endogenous GABA. Nevertheless, some neuro-endocrine effects of BZD are mediated through actions on BZD receptors in the pituitary gland: we reported an inhibition of TRH induced PRL release by diazepam (treatment of 7 days) in anxious patients.