Avexitide (Exendin (9-39)) is a specific and competitive GLP-1 receptor antagonist. In Vitro: GLP-1 plays a role in the control of fasting glucose. Avexitide (Exendin (9-39)), a truncated form of the GLP-1 agonist exendin-4, is a specific GLP-1 receptor antagonist^[1]. In Vivo: Continuous subcutaneous infusion of Avexitide (Exendin (9-39)) significantly raises fasting blood glucose levels in SUR-1 ^-/- mice without affecting glucose tolerance^[2].