Key Points
- To determine the developmental timelines, tissue distribution, and pituitary hormonal dependence of angiotensin-converting enzyme (ACE) isozymes in the rat testis and epididymis.
- Measured soluble and particulate ACE activity across developmental time points (4 to 10 weeks of age) in rat testis and epididymal regions using biochemical assays and [3H]captopril autoradiography.
- Conducted surgical hypophysectomy in 10-week-old rats to assess the pituitary gland's regulatory effect on testicular and epididymal ACE isozymes.
- Particulate ACE was present in epididymal ducts at 4 weeks, testicular ACE emerged between 4 and 6 weeks, and soluble epididymal ACE appeared between 6 and 7 weeks along a proximal-to-distal gradient.
- Hypophysectomy in 10-week-old rats depleted greater than 95% of ACE activity from the testis and soluble epididymal fractions, while particulate epididymal ACE levels remained largely unchanged.
Structured PICO
PPopulationRats (evaluated at 4, 6-7, and 10 weeks of age)
IInterventionHypophysectomy (in 10-week-old rats) and developmental observation
CComparatorIntact rats / different age groups
OOutcomeAngiotensin-converting enzyme (ACE) activity and localization in testis and epididymissurrogate
The study demonstrates that soluble ACE in the epididymis is pituitary-dependent and likely derived from membrane-associated ACE in the testis, whereas particulate ACE in the epididymis is synthesized separately.