Iso-renin of extrarenal origin. "The tissue angiotensinogenase systems".

Enzymes, similar to kidney renin, are present in extrarenal tissue of most mammals; they hydrolyze angiotensinogen to form angiotensin I. We suggest that these enzymes be called angiotensinogenases. Angiotensinogenase concentrations in extrarenal tissue can exceed those in the kidney. The enzyme has been obtained in pure crystalline form. Angiotensinogenases are part of a complex enzyme system which leads to local production of angiotensin. Results indicating a biologic role of the angiotensinogenase system in brain, adrenal gland, uterus and tissue culture are discussed.