Glucagon-like peptide-1 (GLP-1) is an incretin hormone that lowers blood glucose after meals in type 2 diabetes mellitus. The therapeutic potential of GLP-1 in diabetes is limited by rapid inactivation by the enzyme dipeptidylpeptidase-4 (DPP-4). Metformin has been reported to inhibit DPP-4. Here we investigated the acute effects of metformin and GLP-1 alone or in combination on plasma DPP-4 activity, active GLP-1 concentrations, and glucose lowering in type 2 diabetes mellitus.
Cuthberston, J., Patterson, S., O'Harte, F., & Bell, P. (2011). Addition of metformin to exogenous glucagon-like peptide-1 results in increased serum glucagon-like peptide-1 concentrations and greater glucose lowering in type 2 diabetes mellitus. Metabolism , 60(1), 52-56. https://doi.org/10.1016/j.metabol.2010.01.001