The role of angiotensin-converting enzyme in the rat epididymis

Abstract

In order to investigate the role of renin angiotensin in the epididymis, angiotensin-converting enzyme (ACE) activity and angiotensin I (AI) and angiotensin II (AII) concentrations were measured in the male reproductive tract and blood serum of the rat. High ACE activity was detected in the rat epididymis, with a major part of the activity being associated with epididymal spermatozoa. When spermatozoa were prevented from entering the epididymis by efferent duct ligation, the ACE activity in the epididymis was greatly reduced. The epithelial cells lining the epididymal duct were also shown to possess ACE activity which was dependent upon circulating androgens. Treatment of male rats with captopril at a single oral dose (20 mg/kg) significantly inhibited the ACE activity in the blood serum but had no effect on the activity of the epididymal fluid. The intraluminal ACE was protected from the circulating captopril by the blood-epididymis barrier. Long-term treatment with captopril (20 mg/kg per day, 8 weeks), however, caused an increase in blood serum ACE activity but was without effect on intraluminal ACE. The fertility and fecundity of male rats after treatment were apparently normal. The concentrations of AI and AII were high in the epididymal plasma and epididymal cell when compared with the respective concentrations in blood serum. The intraluminal AII concentration found (13 nmol/l) was close to the threshold concentrations that stimulate anion (and fluid) secretion in cultured epididymal epithelium in vitro. The high intraluminal AII concentration could not have been derived from the testicular fluid or spermatozoa since the rete testis fluid and sperm contained little AII.(ABSTRACT TRUNCATED AT 250 WORDS)

Sperm-specific expression of angiotensin-converting enzyme (ACE) is mediated by a 91-base-pair promoter containing a CRE-like element.

“…The results from the -91tACEpLacI trans-VOL. 13,1993 on May 11, 2018 by guest (43). Other investigators have speculated that testis ACE may play a role in regulating sperm motility (40) or capacitation (39).…”

Regulation of luminal acidification in the male reproductive tract via cell–cell crosstalk

“…All components of the renin-angiotensin system (RAS) are present in the lumen of the epididymis, and play a key role in male fertility (Esther et al, 1996;Hagaman et al, 1998;Krege et al, 1995;Leung and Sernia, 2003;Ramaraj et al, 1998;Saez et al, 2004;Speth et al, 1999;Wong and Uchendu, 1990). High concentrations of angiotensin I (ANGI) and ANGII have been detected in the lumen of the epididymis (Wong and Uchendu, 1990). Principal cells produce ANGI, which is then secreted into the lumen (Wong and Uchendu, 1990).…”

“…High concentrations of angiotensin I (ANGI) and ANGII have been detected in the lumen of the epididymis (Wong and Uchendu, 1990). Principal cells produce ANGI, which is then secreted into the lumen (Wong and Uchendu, 1990). ANGI is converted to ANGII by the angiotensin I converting enzyme (ACE).…”

Eritropoietin Hormonu ve ACE İnhibitörü, Erişkin Erkek Sıçanların Sperm Parametrelerini Doxorubicin Toksisitesine Karşı Korur

“…The sACE, rather than the tACE, is responsible for male fertility. The ACE is involved in the regulation of fluid and electrolyte transport within the epididymis during the A-II activation and it is thus involved locally in the RAS of the epididymis [19,20] . The therapeutic effects of DP and RAM against the DXR-induced toxicity have been demonstrated recently [21] .…”