GCG and renal fibrosis: However, few studies have classified whether glucagon-like peptide-1 (GLP-1) mediates the protective effect of DPP-4 inhibitors on renal fibrosis, and most experiments focused on the effect of DPP-4 inhibitors and GLP-1 agonists have been on activated myofibroblasts derived from fibroblasts and EMT and infiltrated cells.