GCGR and diabetes mellitus: Glucagon receptor inhibition decreases hyperglycemia in various animal models of diabetes (Gu et al., 2009; Johnson et al., 1982; Brand et al., 1994; Sloop et al., 2004; Mu et al., 2011; Sorensen et al., 2006), as well as in patients with type 2 diabetes (Kelly et al., 2015).