y-Butyrolactone

Abstract y-Butyrolactone is an oily liquid used as a polymer solvent in products such as paint and nail polish removers. Liquids and powders containing y-butyrolactone were marketed as dietary supplements under product names such as Renew trient, Revivarant, Blue Nitro, Gamma G; these generally claimed improved physical performance, muscle building, reduced stress, and enhanced sexual activity and sleep. In January 1999, after these products had been associated with at least 55 adverse health events and one death, the U.S. Food and Drug Administration urged a voluntary re call of all dietary supplements containing y-butyrolactone. The oral LD5a in rats is 17.2 ml/kg. Rats display absence like seizures after systemic administration of y-butyrolactone or microinfusion of its metabolite, y-hydroxybutyric acid (GHB), into the ventrobasal nucleus of the thalamus. y-Butyrolactone may possess limited y-aminobutyric acid agonist (GABA) activity. GHB is used as a relatively specific inhibitor of central dopamine release ( 3 ). It is suggested that GHB modulates the basal and K+-evoked release of GABA and glutamate in the thalamic ventrobasal relay nuclei (1). GHB-induced absence seizures may regulate GABAA receptor a-1 and a-4 gene expression in thalamic relay nu clei as a compensatory mechanism by which absence sei zures are terminated (2).