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Regulation of iNOS expression and glutathione levels in rat liver by oxygen tension
Author(s) -
Miralles Cristina,
Busquets Xavier,
Santos Carmen,
Togores Bernat,
Hussain Sabah,
Rahman Irfan,
MacNee William,
Agustı́ Alvar G.N.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01748-8
Subject(s) - glutathione , intracellular , hyperoxia , reactive oxygen species , oxygen tension , biochemistry , gene expression , chemistry , antioxidant , biology , microbiology and biotechnology , oxygen , gene , enzyme , organic chemistry
Molecular oxygen (O 2 ) regulates the expression of a variety of genes. We hypothesized that O 2 tension may regulate iNOS expression in rat liver through the production of reactive oxygen species (ROS) and the reduction of intracellular glutathione (GSH) levels. To investigate this hypothesis, we determined the effects of hyperoxia upon iNOS induction (both at the protein and mRNA level) and the intracellular concentration of GSH in an isolated in vitro perfused rat liver preparation. To study the potential involvement of ROS in the intracellular signaling pathway linking changes in oxygen tension to gene expression, we repeated these determinations in the presence of the thiol antioxidant N ‐acetyl‐ L ‐cysteine (NAC). We found that 95% O 2 tension caused a significant induction of the iNOS protein and mRNA levels paralleled by a significant fall in intracellular GSH concentration. The addition of NAC (1 mM) to the perfusate during hyperoxia blocked the induction of iNOS and restored GSH levels. These results indicate that molecular O 2 regulates the expression of iNOS in rat liver at the transcriptional level, most likely through the production of ROS and the reduction of intracellular GSH levels.