Serum DPP-4 level was increased in the CKD group, relative to control (2 weeks, 21.1 ± 4.8; 4 weeks, 22.0 ± 6.1; and 8 weeks, 26.4 ± 1.8; vs. 12.6 ± 3.1 for controls; p < 0.05). This evidence concerns the gene DPP4 and chronic kidney disease.