Distribution and some properties of sheep (Ovis aries) angiotension converting enzyme

Angiotensin converting enzyme (ACE) was measured in 15 sheep tissues by spectrophotometric assay with hippuryl-L-histidyl-L-leucine as substrate. Captopril inhibited the ACE activities of all the tissues. The ACE activity was highest in caput epididymidis, corpus epididymidis, cauda epididymidis, kidney and testis. The ACE activity was moderate in retina, little in cornea and lowest in lens. The greater increase in epididymal ACE activity than that of testicular ACE activity on maturation indicates that epididymal ACE may be highly sensitive to hormones. Chloride functioned as non-essential activator of corneal and retinal ACE. The ACE activities of sheep tissues are compared with those found in other species and probable role of ACE in different tissues is discussed.