TY - JOUR
T1 - An apical membrane Na+/H+ exchanger isoform, NHE-3, is present in the rat epididymal epithelium
AU - Kaunisto, Kari
AU - Moe, Orson W.
AU - Pelto-Huikko, Markku
AU - Traebert, Martin
AU - Rajaniemi, Hannu
PY - 2001/6/6
Y1 - 2001/6/6
N2 - 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.
AB - 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.
KW - Bicarbonate
KW - Immunoblotting
KW - Immunohistochemistry
KW - Northern blotting
KW - Sodium-hydrogen antiporter
KW - Sperm motility
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U2 - 10.1007/s004240100530
DO - 10.1007/s004240100530
M3 - Article
C2 - 11417219
AN - SCOPUS:0035013184
VL - 442
SP - 230
EP - 236
JO - Pflugers Archiv fur die gesamte Physiologie des Menschen und der Tiere
JF - Pflugers Archiv fur die gesamte Physiologie des Menschen und der Tiere
SN - 0031-6768
IS - 2
ER -