The renin-angiotensin system and hypertensive left ventricular hypertrophy in the rat

The relationship between left ventricle-to-body weight ratio (LV/BW), mean arterial pressure (MAP, the average of 12 h of intra-arterial monitoring in conscious animals) and plasma renin activity (PRA) was assessed at 12 weeks after unilateral clipping or sham operation in twenty-four one-kidney rats and twenty-six two-kidney rats. The degree of hypertension and left ventricular hypertrophy were similar in one-kidney and two-kidney groups. There was a close linear relationship between LV/BW and MAP which was similar in one-kidney and two-kidney rats. PRA was significantly elevated only in two-kidney rats and was not related to the degree of hypertrophy after accounting for the effect of PRA on MAP. These data suggest that activation of the renin-angiotensin system does not contribute directly to myocardial hypertrophy in rats with renal-clip hypertension.