Diazepam Binding Inhibitor(DBI) is a highly conserved 10 kDa polypeptide which is expressed in various species range from yeast to mammals. As an inverse agonist for benzodiazepine receptors, DBI downregulates inhibitory effects of GABA. It also has potential to induce anxiety. Found in central and peripheral tissues, DBI also participates in metabolism of steroids, which has been known to partially modify GABAA receptor function in the CNS. In peripheral tissues, DBI plays regulatory roles in steroidogenesis. DBI levels have been reported to be decreased in the cerebrospinal fluid obtained from patients with Alzheimer disease.