NOS2 and chronic kidney disease: iNOS decreased 1.22-fold (p < 0.01), while iNOS/Arg increased 1.57-fold (p < 0.001) in ADPKD compared to the control, and iNOS decreased 1.12-fold (p < 0.05) and NOS2/Arg increased 1.22-fold (p < 0.05) compared to the CKD group.