A renin-like enzyme was determined in the acetone-dried tissue of human pituitaries, in both the anterior and posterior pituitaries using Boucher micromethod. The mean pituitary concentration of the renin-like activity (RA) was equivalent to 60.4+/-7.1 (SEM) ng angiotensin II/g tissue protein/h. The possible functional relationship between the hypophyseal and the brain renin-like enzyme is discussed.