The analysis of serum l-Arginine concentration, l-Arginine to asymmetric dimethyl arginine (ADMA) ratio and eNOS level, as well as NOS activity in the endothelial cells isolated from CD73−/− and WT mice are consistent with the development of endothelial dysfunction in mutant mice (Fig. 2). This evidence concerns the gene NOS3 and endothelial dysfunction.