Apelin is an endogenous ligand of seven-transmembrane G protein-coupled receptor APJ. Apelin and APJ are distributed in various tissues, including the heart, lung, kidney, and even in tumor tissues. Studies show that apelin mRNA is highly expressed in the inner stripe of kidney outer medulla, which plays an important role in process of water and sodium balance. Additionally, more studies also indicate that apelin/APJ system exerts a broad range of activities in kidney. Therefore, we review the role of apelin/APJ system in kidney diseases such as renal fibrosis, renal ischemia/reperfusion injur...
