Table 2.

Potential Ethanol-Induced Sources of Reactive Oxygen Species.

Ethanol Metabolism An ↑ in the flux of reducing equivalents into the electron transport chain due to an ↑ in nicotinamide adenine dinucleotide production related to ethanol metabolism (↑ NADH/NAD+ ratio). An ↑ in cytochrome P450 2E1 metabolism of ethanol. An ↑ in alcohol dehydrogenase metabolism of ethanol and accumulation of acetaldehyde (leading to ROS formation and acetaldehyde adduct formation). Nonoxidative metabolism by fatty acid ethyl ester synthase and/or phospholipase D. Ethanol Effects on Antioxidant Proteins and Antioxidant Enzymes Alcohol-induced inhibition of transport proteins responsible for transporting glutathione from cytosol into the mitochondria (e.g., glutathione transport from cytosol into the mitochondria) and ↓ antioxidant enzyme levels and activity (e.g., superoxide dismutase). Activation/Alteration in Neurohormonal Systems Increased autoxidation of catecholamines. An ↑ in angiotensin II and norepinephrine levels.

NOTE: NAD = nicotinamide adenine dinucleotide, NADPH = nictotinamide adenine dinucleotide diphosphate, ROS = reactive oxygen species.

SOURCE: Used with permission from Piano and Phillips 2014.