Production of angiotensin-converting enzyme in rat epididymis

Unilateral ductuli efferentia testis of immature rat were severed in order to interrupt the continuity between testis and epididymis and angiotensin-converting enzyme (ACE) activities were measured 5 weeks after the operation. The epididymal ACE on the operated side increased to nearly the same level as that on the contralateral side, but the testicular ACE activity on the operated side was markedly lower than that on the contralateral side. On immunofluorescent study using antiserum against purified rat lung ACE, ACE could be found in the tubular epithelial cells of the operated epididymis. These results suggest that epididymis itself synthesize ACE without connection to testis.