GCGR and type 2 diabetes mellitus: Currently, several drugs targeting GCGR to simultaneously reduce blood glucose and lipid accumulation have entered clinical development, demonstrating potential for treating obesity, metabolic disorders, and type 2 diabetes.3 For example, retatrutide, a GCGR/glucose-dependent insulinotropic peptide receptor (GIPR)/glucagon-like peptide-1 receptor (GLP-1R) triple agonist developed by Eli Lilly, has entered Phase III clinical trials.