Sleep and dementia
Dec. 20, 2022
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Alcohol is metabolized mainly in the cytosol of hepatocytes by alcohol dehydrogenase (ADH) to produce acetaldehyde. At high levels of alcohol consumption, an enzyme in the endoplasmic reticulum, cytochrome P450 IIE1 (CYP2E1), also becomes involved in metabolizing alcohol to acetaldehyde. A third (and minor) pathway for alcohol metabolism to acetaldehyde involves a catalase-mediated reaction in peroxisomes. Acetaldehyde is further metabolized to acetate in the mitochondria. Alcohol metabolism results in the formation of NADH and, thus, changes the redox state of hepatocytes (ie, increases the ratio of NADH/NAD+). Alcohol metabolism by CYP2E1 and the re-oxidation of NADH via the mitochondrial electron-transport chain both generate reactive oxygen species (ROS) which contribute to tissue damage. Source: (Zakhari 2013). Public domain. Note: The legend for this figure has been modified.