Respiratory activity of isolated rat liver mitochondria following in vitro exposure to oxygen species: a threshold study

Philippe Corbisier, Martine Raes, Carine Michiels, Etienne Pigelolet, Andree Houbion, Edouard Delaive, José Remacle

Research output: Contribution to journalArticlepeer-review

Abstract

Respiratory activity of isolated rat liver mitochondria was assayed following in vitro exposure to oxygen radicals. Our results show that mitochondrial respiration is more sensitive to O2 •- than to H2O2 However, ferrous ions drastically enhance the toxicity of the enzymatic system generating H2O2 because of the production of the hydroxyl radicals. A protection against those oxygen species could be given by SOD in the xanthine/xanthine oxidase system and by catalase with the glucose/glucose oxidase system. The most damaging system was the combination of Fe2+ with H2O2. In this case, OH is formed in a Fenton-like reaction. The fact that the OH2+ with the most damaging molecule accounts for the finding that catalase and desferrioxamine were efficient protectors in this system. Threshold levels of O2 •- and H2O2 able to inhibit the mitochondrial respiration have been estimated. It is concluded that under normal respiration such thresholds are not reached in vivo and that the impairment of the mitochondrial respiratory activity does not seem to originate only from the natural free radical production in those organelles. However, if the production of free radicals is such to exceed the defense capability, like under oxidative stress, then the critical threshold can be surpassed and the respiration impaired leading to irreversible damages.

Original languageEnglish
Pages (from-to)249-263
Number of pages15
JournalMechanisms of Ageing and Development
Volume51
Issue number3
DOIs
Publication statusPublished - 1990

Keywords

  • Mitochondrial damage
  • Oxygen radicals
  • Threshold

Fingerprint Dive into the research topics of 'Respiratory activity of isolated rat liver mitochondria following in vitro exposure to oxygen species: a threshold study'. Together they form a unique fingerprint.

Cite this