DDAH1 and type 2 diabetes mellitus: Although DDAH is generally considered as the major enzyme responsible for more than 80% of ADMA hydrolysis or elimination, only less than 20% of ADMA metabolism counts on renal excretion and AGXT2, which is thought as a mitochondrial aminotransferase expressed primarily in the kidney [44], if the activities of both enzymes had been measured in the liver of T2DM rats, it would have made this study more perfect.