Asymmetric dimethylarginine and hemodynamic regulation in middle-aged men

The goal of this study was to evaluate the role of asymmetric dimethylarginine (ADMA) in the regulation of hemodynamic functions in hypertensive men. It has been suggested that ADMA, as an endogenous nitric oxide synthase inhibitor, is linked to hypertension and vascular reactivity. Sixty-seven men aged 51.1 years (range, 45-55 years) were studied. Plasma ADMA and symmetric dimethylarginine were determined by high-performance liquid chromatography-tandem mass spectrometry. Blood pressure (BP) was measured by 24-hour ambulatory recordings and casual measurements. Hemodynamic regulation was assessed by noninvasive methods. The nitric oxide production was estimated based on plasma nitrate (NO3-) determination. Results showed that plasma arginine derivatives or L-arginine/ ADMA ratio was not associated with BP values observed during 24-hour monitoring or in casual measurements. Systemic vascular resistance, pulse wave velocity, or cardiac output was not associated with plasma ADMA or plasma NO3- levels. No association was found between plasma ADMA and NO3- either. Interestingly, subjects on antihypertensive treatment had lower plasma ADMA concentrations than nontreated subjects (0.30 +/- 0.08 and 0.36 +/- 0.11 mu mol/L, respectively, P =.04) despite higher BP values. In conclusion, these results suggest that plasma ADMA does not have a determinative role in the regulation of hemodynamic functions in Finnish middle-aged men. (c) 2006 Elsevier Inc. All rights reserved.