Angiotensin I converting enzyme in the ejaculate of fertile and infertile men.

ACE has been measured in the seminal plasma of fertile and infertile men according to the method of Cushman and Cheung. High enzyme activity was found in fertile subjects which did not significantly differ from those with oligozoospermia and those with the Sertoli cell-only syndrome. Enzyme activity was significantly lower after vasectomy. The data suggest a higher enzyme/sperm cell ratio in oligozoospermia. Considerable enzyme activity in obstructive azoospermia can be attributed to enzyme formation within either the prostate or the seminal vesicles.