1. Rats on normal sodium diet (group 1) and on chronically maintained low sodium diet (group 2) were studied during a control period, after clipping the renal artery (two-kidney, one-clip hypertension) and after nephrectomy (one-kidney, one-clip hypertension).
2. The low sodium diet neither prevented the development nor changed the severity of two-kidney, one-clip hypertension, and the latter was not accompanied by an increase in plasma renin activity.
3. After nephrectomy arterial pressure further increased and plasma renin activity decreased in group 1, and both remained unchanged in group 2.
4. Blood volume was the same in both groups 10 days before and 10 days after nephrectomy.
5. Sodium does not seem to be ‘necessary’ in the two-kidney, one-clip hypertension although it may play an enhancing role in the one-kidney model.