Effect of angiotensin II and enalapril on transfer of low-density lipoprotein into aortic intima in rabbits

Abstract

To assess the mechanism behind a possible atherosclerosis-promoting effect of angiotensin II, the influence of angiotensin II, noradrenaline, and enalapril on transfer of low-density lipoprotein (LDL) into the arterial wall was investigated in conscious rabbits. Intravascular infusion of angiotensin II (1.4 μg/kg per minute) initially increased the mean blood pressure from 70 to 80 mm Hg to 125 to 150 mm Hg; this effect was transient, and the blood pressure returned to baseline values within 2 hours, despite continuous infusion of angiotensin II. The normalized influx of LDL into the aortic intima, determined after in vivo exposure to 125I-LDL for 1 hour, was 88±17 (n=6), 12±12 (n=5), and 28±6 (n=5) nL/cm2 per hour (mean±SEM) during angiotensin II infusion at high blood pressure, during angiotensin II infusion after the blood pressure had been normalized, and during continuous saline infusions, respectively (P