[Asymmetric dimethylarginine: metabolism, arginine paradox, pathophysiology].

Pathophysiology of asymmetric dimethylarginine (ADMA), an endogenous competitive inhibitor of NO synthase, has been a subject of intensive research activity during last years. The ways of ADMA synthesis and degradation were studied. It was suggested that ADMA plays a considerable role in the realization of so called "Arginine paradox". This paradox refers to the dependence of cellular NO production on exogenous L-arginine despite the saturation of NOS enzymes with intracellular L-arginine. Close association was described between increase in blood ADMA level and endothelial dysfunction accompanied by related pathologies like atherosclerosis, renal insufficiency, hypertension and some others. Some studies have represented ADMA as a strong independent risk factor for cardiovascular complications. Possible reasons are discussed of some experimental data ambiguity as well as the limits of confidence in clinical ADMA analysis.