NOS3 and renal fibrosis: Since Endotheli-1 (ET-1) and nitric oxide systems are important regulators of renal fibrosis [23, 24] we measured ET-1, endothelin receptor A (EDNRA), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) gene expression by real-time PCR.