Influence of sodium restriction upon two models of renal hypertension

1. Restriction of dietary salt intake does not affect the development or maintenance of hypertension in rats with unilateral renal ischaemia whether the contralateral kidney is present (Goldblatt 2 model) or not (Goldblatt 1 model). 2. Acute dietary salt depletion induces a similar loss of sodium and fall in body weight with little change in blood pressure in both normal and hypertensive rats. 3. Excision of the ischaemic kidney in rats with short-term (less than 50 days) Goldblatt 2 hypertension restores the mean blood pressure to normal, whereas Goldblatt 1 hypertensive rats show only a partial response. Previous salt depletion of this model enhances the blood pressure response to nephrectomy. 4. Sodium retention plays no part in the development or maintenance of Goldblatt 2 kidney hypertension. However, although sodium retention is normally involved in the Goldblatt 1 model, hypertension can develop in the absence of dietary sodium.