Abstract
A direct relationship between the level of renin in the blood and the height of the blood pressure in humans has not been definitely established. Hitherto, the development of methods of measurement of renin has been fraught with great technical difficulties. Recently, Gould et al. developed a sensitive method for the assay of renin in human serum. The use of this method has enabled us to undertake a study of the relationship of the level of circulating renin in the blood to the height of the blood pressure under various conditions in patients with essential hypertension. The main purpose of this study was to determine whether there is a relationship between the level of circulating renin in the blood and the fall of blood pressure which occurs as a result of hospitalization and reduction of dietary sodium.