In preclinical work using mouse models of T2D and/or pancreatic islets obtained from human organ donors with T2D, prostaglandin E2 (PGE2) limits expected insulin secretion in response to both glucose and incretin hormones such as glucagon-like peptide 1 (GLP-1), actively contributing to β-cell dysfunction [9,10,11]. This evidence concerns the gene GCG and type 2 diabetes mellitus.