A possible role of the kidney in activating a renin preinhibitor

In order to verify the possibility than human plasma and kidney can activate a renin preinhibitor (Phospholipid) into inhibitor (lysophospholipid), constant quantities of preinhibitor were added to plasma and kidney homogenate. Addition of preinhibitor to plasma did not modify the quantity of Angiotensin I that developed. On the other hand, addition of preinhibitor to crude kidney homogenate, followed by incubation with human angiotensinogen, caused a significant fall in the quantity of Angiotensin I generated. While plasma is deficient in the specific enzyme delegated to the transformation of preinhibitor into inhibitor, it appears that this enzyme is present in the kidney.