[Inhibitors of arginase pathway in L-arginine metabolism as a new class of antihypertensive drugs: action of urea on oxidative and nonoxidative metabolism of L-arginine and vascular tone in chronic hypertension].

: It has been studied an action of chronic urea introduction (40 mg/kg, 14 and 28 days) as arginase inhibitor on nonoxidative (arginase activity, urea, polyamines content) and oxidative (NOS activity, nitrite- and nitrate-anion content) metabolism of L-arginine in aorta, heart, plasma and erythrocytes of SHR. It has been shown that urea is an inhibitor of not arginase only, but also ornitinedecarboxilase (ODK) reactions, limiting L-arginine consumption for urea and polyamines synthesis and thus facilitating its utilization for nitric oxide synthesis by NOS. These exogenous effects of urea are not accompanied by amelioration of tissue ischaemization within cardiovascular system. It has been shown that exogenous urea down regulate blood pressure without any normalization of endothelim-dependent reactions of smooth muscle cells on acetylcholine in SHR.