INS and chronic kidney disease: It was shown that treatment of 3T3-L1 adipocytes with urea at concentrations similar to those in CKD patients led to the production of ROS, caused insulin resistance, increased the expression of adipokines, retinol-binding protein 4 (RBP4), and resistin, and increased the level of O-linked N-acetylglucosamine (O-GlcNAc) modified insulin signal molecules.