TY - JOUR
T1 - Respiratory activity of isolated rat liver mitochondria following in vitro exposure to oxygen species: a threshold study
AU - Corbisier, Philippe
AU - Raes, Martine
AU - Michiels, Carine
AU - Pigelolet, Etienne
AU - Houbion, Andree
AU - Delaive, Edouard
AU - Remacle, José
PY - 1990
Y1 - 1990
N2 - 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.
AB - 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.
KW - Mitochondrial damage
KW - Oxygen radicals
KW - Threshold
UR - http://www.scopus.com/inward/record.url?scp=0025191284&partnerID=8YFLogxK
U2 - 10.1016/0047-6374(90)90075-Q
DO - 10.1016/0047-6374(90)90075-Q
M3 - Article
C2 - 2308396
AN - SCOPUS:0025191284
SN - 1872-6216
VL - 51
SP - 249
EP - 263
JO - Mechanisms of Ageing and Development
JF - Mechanisms of Ageing and Development
IS - 3
ER -