GCGR and diabetic kidney disease: We also observed that aldosterone induces CCN2 in several kidney cell-types, most notably fibroblasts, and that CCN2, in turn, downregulates VSMC Glp1r and MDCK cell Gcgr. Thus, Glp1r and Gcgr downregulation are caused by the paracrine actions of CCN2 (and potentially other growth factors) in diabetic kidney disease.