Region- and Cell-specific Differences in the Distribution of Carbonic Anhydrases II, III, XII, and XIV in the Adult Rat Epididymis

Abstract

We employed RT-PCR followed by light microscope immunocytochemistry on St. Marie's- and Bouin's-fixed tissues to define the distribution of carbonic anhydrase (CA) isoforms in the male reproductive tract. The data revealed that CA II, III, IV, XII, and XIV were expressed in rat epididymis. Whereas CA III was found in principal cells of all epididymal regions, CA II was localized in narrow cells of the initial segment and principal cells of all regions. CA XII expression was most intense in the corpus and proximal cauda regions, where it appeared over the basolateral plasma membranes of principal cells. Narrow cells of the initial segment also revealed intense reactions, as did basal cells of the corpus and proximal cauda regions. Principal cells of the initial segment and proximal caput regions showed diffuse apical cytosolic reactions and occasional basolateral staining for CA XIV, whereas principal cells of distal regions showed more diffuse cytosolic reactions highlighting both apical and basal regions of the cell, with basal cells also being reactive. These data suggest subtle differences in cell type and subcellular- and region-specific distributions for CAs in their role of fine-tuning pH in the lumen, cell cytosol, and intervening intercellular spaces of the epididymis.

The Epididymis: Embryology, Structure, Function And Its Role In Fertilization And Infertility

“…They are clearly defined by the many mitochondria in the apical cytoplasm, the few microvilli at the luminal border and a nucleus that is located in the upper half of the cell cytoplasm (Adamali & Hermo, 1996;. These cells are related to sperm quiescence and to the regulation of the pH in the lumen through the production of enzymes of the carbonic anhydrase family (Hermo et al, 2005).…”

“…Clear cells are also endocytic cells and may be responsible for the clearance of proteins from the epididymal lumen. They normally take up the contents of the cytoplasmic droplets released by the spermatozoa as they transit through the duct (Hermo et al, 1994(Hermo et al, , 2005.…”

The Expression Patterns of Connexin Isoforms in the Rat Caput Epididymis During Postnatal Development

“…The chief function of the principal cell is the secretion of a bulk of proteins to regulate luminal protein concentrations (Robaire et al, 2000), while the narrow cell is involved in the intracellular transport of specific molecules between the lumen and epithelial cells (Robaire et al, 2006). The clear cell is likely responsible for the removal of luminal proteins, and the apical cell is related to the regulation of luminal pH (Hermo et al, 2005). It is reasonable to consider that different cellular compositions along the epididymis would lead to the creation of a specific luminal microenvironment in each epididymal region, resulting in the regionalization of epididymal functions.…”

Autosomal recessive hyponatremia due to isolated salt wasting in sweat associated with a mutation in the active site of Carbonic Anhydrase 12

“…CA12 is expressed in many cell types in various tissues including kidney, mesothelial cells lining body cavities and sweat and salivary glands (Ivanov et al 2001;Liao et al 2009). Immunohistochemical studies show that CA12 is located in the basolateral membranes of epithelial cells (Ivanov et al 2001;Halmi et al 2004;Karhumaa et al 2000;Hermo et al 2005;Hynninen et al 2004;Kyllonen et al 2003) with its active site located outside the cell (Whittington et al 2001).…”