| Abstract: | Abstract— The effect of 100% O2 at one atmosphere on carbohydrate metabolism in cell-free homogenates of rat brain was studied under different experimental conditions. The principal findings were the following: - 1 Compared to 10% O2-90% N2, oxygen at one atmosphere inhibited metabolism of α-oxoglutarate and depressed the net synthesis of ATP. With glucose as substrate, accumulation of ATP was also markedly inhibited but substrate utilization was only slightly affected.
- 2 Glycolysis in brain was relatively resistant to oxygen toxicity, except in the presence of added Cu2+.
- 3 With α-oxoglutarate as the substrate, inhibition of the formation of ATP occurred earlier than inhibition of substrate utilization, indicating the particular sensitivity of oxidative phosphorylation to inactivation by oxygen in vitro.
- 4 Cu2+ and Fe2+ accentuated oxygen toxicity but appeared to act by different mechanisms. Co2+ exerted a protective effect.
- 5 The sulphydryl compounds, dithiothreitol and reduced glutathione, strongly diminished the toxic effect of oxygen.
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