Role o f the Lung in Angiotensin Metabolism

The detection and properties of the enzyme which converts angiotensin I to angiotensin II (converting enzyme) are reviewed. Converting enzyme, which is found principally in the lung, is probably responsible in the intact animal for the conversion of angiotensin I to angiotensin II under physiological conditions, the lung thus being the principle site of conversion. The enzyme is distributed in the endothelial cells of the pulmonary capillaries. Conversion of angiotensin I to angiotensin II depends on the area of the vascular bed and the rate of blood flow through the pulmonary circulation. The lungs, in addition to their central role in respiration, play an important part in the metabolism of some vasoactive sub stances. As long ago as 1925, Starling and Vemey58 showed that the isolated kidney could not be perfused using a simple ci