The expression of mRNA for inducible nitric oxide synthase (iNOS) in rat
epithelial cells of epididymis was investigated with reverse transcription
followed by polymerase chain reaction. Immunocytochemical reaction for iNOS
was performed to confirm the enzyme’ s localization in the epididymal
epithelium. Additionally, an indirect spectrophotometric method for nitric
oxide (NO) determination was applied for measurement of nitrite production by
cultured epididymal epithelial cells.
Inducible NOS mRNA was detected in freshly isolated epithelial cells, in
cultured cells without stimulation as well as in cultured cells after
stimulation by lipopolysaccharide and interferon-gamma. Inducible NOS
immunoreactivity was observed in the apical part of epithelial cells of
epididymal sections and in the cytoplasm of cells in culture. Release of
nitrite was observedin vitro in both the unstimulated
and stimulated cells of caput (1·44 ± 0·94
v. 4·37 ± 2·42 µM) and cauda
(0·69 ± 1·21 v. 5·21
± 2·76 µM) epididymis (P <
0·001).
To the best of our knowledge, this is the first study to demonstrate iNOS in
the epididymal epithelial cells of the rat. Nitric oxide released by
epididymal epithelial cells may act on cells and tissues located nearby. The
results may help explain epididymal function: sperm storage, passage and
maturation. Excessive epididymal NO production may also play a role in the
inflammatory infertility of the male.
Extra keyword: iNOS
Tumor Killing by CD4+ T Cells Is Mediated via Induction of Inducible Nitric Oxide Synthase-Dependent Macrophage Cytotoxicity