Augmented expression of cardiac atrial natriuretic peptide system in hypertensive rats

The present study was aimed at investigating the regulation of atrial natri uretic peptide (ANP) system in association with either enhanced or attenuat ed activity of the renin-angiotensin system (RAS), The cardiac tissue mRNA and peptide levels of ANP were measured in rats with two-kidney, one clip ( 2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertension. Plasma renin concentration was increased in 2K1C hypertension along with increases of r enin mRNA and protein contents in the clipped kidney. On the contrary, it w as suppressed in DOCA-salt hypertension along with decreases of renin mRNA and protein contents in the remaining kidney. The plasma ANP concentration was similarly increased in both models of hypertension, The cardiac tissue ANP contents were not significantly changed, but the tissue ANP mRNA levels were upregulated in the hypertrophied heart in these two models of hyperte nsion. It is suggested that the cardiac ANP system is transcriptionally enh anced by cardiac hypertrophy associated with hypertension, independent of t he systemic RAS.