Chronic l -Arginine Administration Attenuates Cardiac Hypertrophy in Spontaneously Hypertensive Rats

Abstract

Nitric oxide inhibits proliferation and migration of vascular smooth muscle cells and contractility of cardiomyocytes in vitro. In spontaneously hypertensive rats (SHR), evidence suggests intrinsic abnormalities of the l-arginine–nitric oxide axis, such as low cGMP-dependent protein kinase in the heart and abnormal l-arginine metabolism. To investigate the in vivo effect of l-arginine on cardiac hypertrophy, 30 SHR and 30 Wistar-Kyoto rats (WKY) were randomly grouped to receive l-arginine (7.5 g/L in drinking water) or vehicle for 12 weeks. l-Arginine treatment did not affect body weight or arterial pressure in either strain. In vehicle-treated animals, the heart/body weight ratio was significantly higher in SHR than in WKY (P<.01). l-Arginine treatment decreased the heart/body weight ratio in SHR (P<.05) but did not affect it in WKY. Expression of skeletal α-actin mRNA, known to be expressed in the hypertrophied myocardium, was attenuated in l-arginine–treated SHR compared with vehicle-treated S...