[Generation of the superoxide radical and lipid peroxidation in skeletal muscles]

The production of O2-, H2O2 and ADP X Fe3+-dependent lipid peroxidation (LPO) in skeletal muscle sarcoplasmic reticulum and mitochondria was studied. It was shown that in the muscle cell the O2- sources and LPO substrates are spatially separated, i. e., the former are localized in mitochondrial membranes, while the latter are predominantly located in sarcoplasmic reticulum membranes. It is concluded that in isolated subcellular fractions of the muscle LPO is generated via direct reduction of ADP-Fe3+ by corresponding redox chains without the involvement of free O2-. The feasibility of intermembrane diffusion of O2- in vivo is postulated, which results in the initiation by mitochondrial O2- of LPO in sarcoplasmic reticulum membranes.