3 research outputs found
Isoforms of Na+, K+-ATPase in human prostate; specificity of expression and apical membrane polarization
The cellular distribution of Na+, K+-ATPase
subunit isoforms was mapped in the secretory epithelium
of the human prostate gland by immunostaining with
antibodies to the a and B subunit isoforms of the
enzyme. Immunolabeling of the a l , B1 and B2 isoforms
was observed in the apical and lateral plasma membrane
domains of prostatic epithelial cells in contrast to human
kidney where the al and B1 isoforms of Na+, K+-
ATPase were localized in the basolateral membrane of
both proximal and dista1 convoluted tubules. Using
immunohistochemistry and PCR we found no evidence
of Na+, K+-ATPase a 2 and a 3 isoform expression
suggesting that prostatic Na+, K+-ATPase consists of
allí31 and allí32 isozymes. Our immunohistochemical
findings are consistent with previously proposed models
placing prostatic Na+, K+-ATPase in the apical plasma
membrane domain. Abundant expression of Na+, K+-
ATPase in epithelial cells lining tubulo-alveoli in the
human prostate gland confirms previous conclusions
drawn from biochemical, pharmacological and
physiological data and provides further evidence for the
critica1 role of this enzyme in prostatic cell physiology
and ion homeostasis. Na+, K+-ATPase most likely
maintains an inwardly directed Na+ gradient essential for
nutrient uptake and active citrate secretion by prostatic
epithelial cells. Na+, K+-ATPase may also regulate
lumenal Na+ and K+, major counter-ions for citrat