The changes of angiotensin II and nitric oxide and their association with ambulatory blood pressure in essential hypertension

Objective:To evaluate the changes of plasma angiotensin Ⅱ(Ang Ⅱ) and serum nitric oxide (NO) and their association with circadian rhythm of blood pressure in essential hypertension(EH).Methods:50 EH patients and 38 normotensive controls(NC) were underwent 24 hour noninvasive ambulatory blood pressure monitoring(ABPM) and examined Ang Ⅱ by radioimmunoassay (RIA) and NO by colorimeteric. Meanwhile left ventricular structure was assessed by echocardiography.Results:①The plasma Ang Ⅱ level in EH patients was higher and serum NO level was lower than those in NC(all P 0.01 ). The change was related to the severity of disease. ②In EH groups , plasma Ang Ⅱ has negative correlation with serum NO(r=- 0.4999 ,P 0.01 ). ③According to results of the monitoring, 50 EH patients were divided into dipper hypertension and non dipper hypertension. In non dippers, night systolic blood pressure and night diastolic blood pressure were higher than those in dippers; Moreover, Ang Ⅱ and left ventricular mass were significantly improved, and NO was markedly reduced. There was a strong negative correlation between nocturnal blood pressure fall and Ang Ⅱ(r=- 0.421 ,P 0.05 ), while a correlation with NO(r= 0.305 ,P 0.05 ).Conclusion:The imbalance between the Ang Ⅱ and NO may be the important cause of the hypertension and has effects on circadian rhythm of blood pressure in EH.