Experiments Concerning the Site of Renin Formation

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Abstract
Renin was confined to the fraction A (alcohol insoluble fraction), the intraven. injn. of 0.5 ml of which produced in nephrectomized rabbits, blood pressure rises of 50-60 mm Hg maintained for 40-50 min. Two repeated injns. of the same did not cause any tachyphylaxis, while 3 repeated injns. produced a slight one. This vasopressor factor was abundant in the cortex, whereas it was almost absent in the medulla. The vasodepressor factor was confined to fraction B (alcohol soluble fraction), the intraven. injn. of 0.5 ml of which caused in the nephrectomized rabbit a blood pressure drop of about 30 mm Hg, which returned to the normal in several min. The vasodepressor factor was found more in the cortex than in the medulla. The fraction A from sodium tartrate-treated rabbits possessed the vasopressor activity resembling that from the normal rabbit. The vasodepressor effect of fraction B from the treated animals was, however, rather increased. This factor was more abundant in the medulla than in the cortex. The mixture of one part of fraction A and two parts of fraction B also produced the same vasopressor effect as the fraction A. This shows that the fraction B does not interfere with the vasopressor effect of renin. From the above observation, it is considered that sodium tartrate does not reduce extractable renin in the kidney, though it slightly increases the vasodepressor fraction in the renal extract. The findings do not conform to the conclusions of Friedman and Kaplan.