LOSARTAN PREVENTS SALT-INDUCED HYPERTENSION IN REDUCED RENAL MASS RATS

A reduction in functioning renal mass through surgical ablation leads to the development of hypertension and chronic renal failure in rats. Reduced renal mass (RRM) hypertension is more severe and develops more quickly if rats are on high salt intake. It has previously been shown that hypertension in these rats can be prevented by treatment with an giotensin-converting enzyme inhibitors. The current experiment examine d the effect of losartan, an angiotensin II antagonist, on blood press ure in RRM and intact rats after a 3-fold increase in salt intake. It was found that chronic treatment with i.v. losartan (3 mg/kg/day) comp letely prevented sodium-induced hypertension in the RRM rats, whereas neither increased salt intake nor losartan treatment affected blood pr essure in the intact rats. The antihypertensive effect of losartan was associated with an apparent renoprotective effect in RRM rats (blood urea nitrogen concentration rose in untreated animals, but remained st able in treated animals), but was not accompanied by chronic changes i n water or sodium balance. The ability of losartan to prevent RRM hype rtension suggests that angiotensin II is necessary for the development of this model of hypertension.