The problem of the possible significance of renin in the production of hypertension is fundamentally important in determining possible approaches to the therapeusis of this disorder. The available evidence on this point is, however, conflicting. Thus, Harrison, Blalock, Mason and Williams1 and Prinzmetal, Friedman and Abramson2 observed that extracts of ischemic dog kidneys cause a greater rise in blood pressure than do those of normal kidneys. On the other hand, Pickering and Prinzmetal3 failed to observe an augmented pressor effect in extracts of ischemic rabbit kidneys, while Beckwith and Chanutin4 found that the pressor activity of the kidney remnants of rats with hypertension due to subtotal nephrectomy was less than that of normal kidneys from rats with normal blood pressure.
Several possible explanations for the divergent results obtained by previous workers suggest themselves: (1) differences in methods of preparation; (2) species differences of the animals (dog,