Hyperoxia enhances expression of γ-glutamyl transpeptidase and increases protein S-glutathiolation in rat lung

Roy G. Knickelbein, David H. Ingbar, Tamas Seres, Kris Snow, Richard B. Johnston, Olutoyin Fayemi, Francine Gumkowski, James D. Jamieson, Joseph B. Warshaw

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

By participating in glutathione (GSH) synthesis, γ-glutamyl transpeptidase (GGT) influences the GSH redox cycle, which is a major contributor in protecting against reactive oxygen metabolites. This study determined the effect of prolonged exposure of neonatal rats to >98% oxygen on expression of GGT and on GSH metabolism. Lungs of neonatal rats chronically exposed to hyperoxia had increased expression of GGT mRNA, resulting in significantly higher GGT protein levels and enzyme activity than in lungs of animals raised in room air. Hyperoxia also upregulated glucose- 6-phosphate dehydrogenase, but Na-K-ATPase activity was not changed. GGT mRNA, protein level, and enzyme activity returned to control levels after recovery in room air for 3 days. Levels of GSH, glutathione disulfide, and protein-bound GSH (S-glutathiolated protein) rose with hyperoxia and fell during recovery. S-glutathiolation is likely a mechanism for protection and a regulatory modification of protein sulfhydryl groups. Hyperoxia-induced upregulation of GGT and the concomitant increase in protein S-glutathiolation appear to be additional components fundamental in protecting the lung against oxidative injury.

Original languageEnglish (US)
Pages (from-to)L115-L122
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume270
Issue number1 14-1
DOIs
StatePublished - Jan 1996

Keywords

  • disulfides
  • immunocytochemistry
  • messenger ribonucleic acid
  • oxidation-reduction
  • γ-glutamyl transferase

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