GCGR and type 2 diabetes mellitus: With respect to GCGR antagonist, several previous reports have demonstrated that GCGR is a plausible target for the treatment of T2D by using various substances including small-molecules (compound A, bicyclic peptide, NNC 25-0926) [7], [8], [17], [18], antisense oligonucleotides [9], [10] and monoclonal antibodies [11]–[13], [19].