Renin lowers blood-pressure.

The hypothesis that increased plasma-renin tends to lower blood-pressure is proposed. Binding of renin to blood-vessel walls is postulated to have some vasodilator action which would oppose the usual blood-pressure-raising action caused by generation of angiotensin. Many of the effects of saralasin and of converting-enzyme inhibitor on blood-pressure in relation to concentrations of renin in blood plasma and in the kidneys seem to support this hypothesis.