Effect of dietary chloride on salt-sensitive and renin-dependent hypertension.

Abstract

We have previously reported that (1) selective dietary sodium loading (without chloride) does not produce hypertension in rats of the Dahl salt-sensitive strain (DS) and (2) selective chloride loading (without sodium) lowers plasma renin activity in the intact Sprague-Dawley rat maintained on a low NaCl diet. The present study examined the effect of selective dietary chloride loading on two models of hypertension: the DS and the renin-dependent one-kidney, one clip Sprague-Dawley rat. The DS were pair-fed (n = 7/group) a "normal" NaCl, a high NaCl (4%), or a "normal" sodium-high chloride diet for 11 weeks. From Week 7 until the end of the experiment, the high NaCl-fed animals had higher (P .ltoreq. 0.05) blood pressures than animals fed either the normal NaCl or normal sodium-high chloride diet, which were not different from each other. Thus, in the DS, the hypertension depends on high dietary intakes of both sodium and chloride. In one-kidney, one clip hypertensive rats, selective chloride loading failed to lower plasma renin activity (9 .+-. 1 vs 7 .+-. 1 ng angiotensin I/ml/hr) or to prevent hypertension (160 .+-. 10 vs 166 .+-. 9 mm Hg). Thus, selective dietary chloride loading (without sodium) does not alter blood pressure in either salt-sensitive or renin-dependent hypertension.