Increase in extracellular glutatione peroxidase in plasma and lungs of mice exposed to hyperoxia.
Extracellular glutathione peroxidase (E-GPx) is a selenium-dependent enzyme that can reduce hydrogen peroxide and phospholipid hydroperoxides. E-GPx is found in plasma and extracellular fluids such as bronchoalveolar lavage fluid. Because lung is one of the tissues that is capable of synthesizing and secreting E-GPx, the effect of exposure to hyperoxia on E-GPx in plasma and lung were studied in an injury model of hyperoxia exposure in adult mice. Exposure to 100% oxygen for 72 h resulted in an increase of 55% in plasma GPx activity and an increase of 50% in the amount of E-GPx protein in the plasma. Exposure to hyperoxia was also associated with an increase in the amount of E-GPx protein in lungs. The 7-fold increase in the amount of E-GPx protein in lungs was not due to plasma contamination of lungs from mice exposed to hyperoxia. E-GPx in the lung is calculated to account for 10% of lung GPx activity in control mice. However, E-GPx is calculated to account for 45% of lung GPx activity in the lungs of mice exposed to hyperoxia for 72 h. Further studies are needed to determine whether the increase in lung E-GPx is due to changes in translation or stability of E-GPx. The role of E-GPx in protecting the lung from oxidative damage warrants further study.
Kim
K K
KK
Department of Pediatrics, Stanford University, California 94305-5208, USA.
Whitin
J C
JC
Sukhova
N M
NM
Cohen
H J
HJ
D000818:Animals; D005979:Glutathione Peroxidase / Q000097:blood*; D018496:Hyperoxia / Q000201:enzymology*; D008168:Lung / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010100:Oxygen / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis
D012333:RNA, Messenger; D005979:Glutathione Peroxidase; D010100:Oxygen