The effect of a protein-free diet on the renin-angiotensin system in the rat.

The effects of protein-free diet were studied in the rat. It was shown that the diet led to a decrease in total serum protein, in plasma renin activity, in plasma renin substrate and in blood pressure; and to an increase in haematocrit. A significant linear correlation was found in every combination between the total serum protein, plasma renin activity, plasma renin substrate and systolic blood pressure. In contrast to the plasma renin activity, the renin concentration in the kidney of rats on a protein-free diet was found not to be lower that of the control group. The protein-free diet caused a decrease in the pressor response to injected angiotensin II.