Abstract
An acidic milieu is required for sperm maturation and for keeping sperm quiescent during storage in the cauda epididymidis. Previous studies have implicated a Na+/H+ exchanger (NHE) in epididymal acidification together with carbonic anhydrase (CA) and vacuolar proton adenosine triphosphatase (H+-ATPase). The present studies were undertaken to discover whether the NHE isoform involved is NHE-3, which is known to mediate Na+ and HCO3 - absorption in renal tubules. Using the reverse transcription polymerase chain reaction technique (RT-PCR), Northern blot analysis and in situ hybridization, NHE-3 mRNA was detected mainly in the cauda epididymis and to a lesser extent in other regions of the epididymis. Immunohistochemical studies showed that NHE-3 was present in the apical membranes of the epithelial principal cells and confirmed that its expression is strongest in the cauda region, decreasing towards the more proximal regions. Immunoblotting showed a similar expression pattern. These results demonstrate that NHE-3 is expressed in the rat epididymal duct with strongest expression in its cauda region. These findings are thus consistent with the possibility that NHE-3 in the epididymal duct is involved in luminal Na+ and/or HCO3- absorption, as in the renal proximal tubule, and thereby in the regulation of sperm motility and maturation.
Original language | English (US) |
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Pages (from-to) | 230-236 |
Number of pages | 7 |
Journal | Pflugers Archiv European Journal of Physiology |
Volume | 442 |
Issue number | 2 |
DOIs | |
State | Published - Jun 6 2001 |
Keywords
- Bicarbonate
- Immunoblotting
- Immunohistochemistry
- Northern blotting
- Sodium-hydrogen antiporter
- Sperm motility
ASJC Scopus subject areas
- Physiology
- Clinical Biochemistry
- Physiology (medical)