Effects of ethanol on mitochondrial oxidations

Abstract

1.1. Effects of ethanol on mitochondrial oxidations in vitro have been studied.2.2. Ethanol in relatively low concentrations was found to stimulate the O2 uptake of rat-liver mitochondria with β-hydroxybutyrate as the substrate. With pyruvate, α-ketoglutarate and succinate as substrate ethanol depressed the O2 uptake.3.3. With β-hydroxybutyrate the O2 uptake increased with increasing ethanol concentration to reach a maximum of 130–135% of the control value at 0.5–0.6 M ethanol. The increased O2 could be accounted for by a stoichiometric increase in the acetoacetate formation.4.4. Sonic disruption of the mitochondria prior to incubation nearly abolished the stimulating effect of ethanol on the O2 consumption.5.5. The activity of β-hydroxybutyrate (D-3-hydroxybutyrate: NAD oxidoreductase, EC 1.1.1.30) was not affected by ethanol in concentrations which stimulated the mitochondrial O2 uptake with β-hydroxybutyrate.6.6. The P/O ratio was not lowered by ethanol concentrations which increased the β-hydroxybutyrate oxidation.7.7. It is suggested that ethanol increases the oxidation of the β-hydroxybutyrate, by facilitating its transport into the mitochondria.