EDN1 and diabetes mellitus: Endothelial dysfunction which is a common feature in DM defined by decreased nitric oxide NO and increased endothelin-1 ET-1, ET-1 is reported to be involved in the pathogenesis of DKD, NO is postulated to play a protective role towards ischemic injuries of renal vascular tissues, action mediated via cyclic guanosine monophosphate- protein kinase G (cGMP-PKG) signaling pathway which initiates renal vascular smooth muscle relaxation [13].