Relation of Plasma Renin to Sodium Balance and Arterial Pressure in Experimental Renal Hypertension

Measurements of plasma renin were made in unilaterally nephrectomized dogs with renal artery stenosis and hypertension. Plasma renin was elevated throughout the course of the malignant renal hypertensive disease, and during the first three days only in chronic hypertension. Hypertension was produced by renal artery constriction in unilaterally nephrectomized dogs with prior thoracic caval constriction and in sodium-depleted, left nephrectomized animals. Plasma renin was high in both dogs with caval constriction and sodium depletion before hypertension was added. When the renal artery was constricted, two of the dogs with thoracic caval constriction developed malignant hypertension and a further striking increase in plasma renin occurred. In two other dogs with caval constriction, chronic hypertension developed but plasma renin increased further in only one of the two animals; this occurred during the first four days of hypertension after which plasma renin returned to the high control level. The sodium-depleted dogs developed chronic hypertension following renal artery constriction but no further elevation in plasma renin occurred. Sodium repletion and sodium depletion of chronic hypertensive dogs produced marked changes in plasma renin without alterations in arterial pressure. The present findings revealed a striking correlation between plasma renin and sodium balance but neither bore any relation to the level of arterial pressure.