Regulation by the cAMP cascade of oxygen free radical balance in Mammalian cells

A study is presented of the effect of the cAMP cascade on oxygen metabolism in mammalian cell cultures. Serum-starvation of the cell cultures resulted in depression of the forward NADHubiquinone oxidoreductase activity of complex I, decreased content of glutathione and enhancement of the cellular level of H2O2. Depressed transcription of cytosolic Cu/Zn-SOD 1, mitochondrial glutathione peroxidase and catalase was also observed. Activation of the cAMP cascade reversed the depression of the activity of complex I and the accumulation of H2O2. The effect of cAMP involved the cAMP-dependent protein kinase.