The concentrations of stable metabolites of NO (NO2– і NO3–) in plasma and in erythrocytes, activity of NO-synthase in erythrocytes were estimated in 26 normotensive and in 56 hypertensive (by data of 24-hour monitoring of blood pressure) males at the age from 20 to 35 years old in dependence on hereditary predisposition to essential hypertension. It was shown decreasing of basal level of stable metabolites of NO in plasma and in erythrocytes, and decreasing of NO-synthase activity in erythrocytes in normotensive patients with hereditary predisposition to essential hypertension. The elevation of blood pressure in the patients does not result in significant activation of NO-synthase, but results in the more significant deposition of stable metabolites of NO in erythrocytes than in hypertensive males without family anamnesis of essential hypertension. In young age men with labile elevation of blood pressure and hereditary predisposition to essential hypertension non-oxide activation of NO-system might be first mechanism of cardiovascular system adaptation to increasing vasoconstriction.
