Figure 7: Model of alcohol-induced hepatic steatosis.

During ethanol digestion, NAD+ is converted into NADH by alcohol dehydrogenase and aldehyde dehydrogenase. A low NAD+/NADH ratio represses NAD-dependent deacetylase sirtuin 1 (SIRT1) activity. Reduced SIRT1 activity causes the activation of SREBP1c, ChREBP, and PPARγ. In the early phase, expression of SREBP1c and ChREBP target genes, such as L-PK, FAS, and SCD1, are increased, and then PPARγ target genes including MGAT1 are increased. Expression of PPARγ and its target genes lead to the development of alcoholic steatosis.