MAPK3 and steatosis: Glucagon‐like peptide 1 (GLP‐1) may also be secreted in vivo in response to ISO treatment (Hansen et al., 2004), and although GLP‐1 signaling rather decreases steatosis by promoting fat oxidation, stimulation of the GLP‐1 receptor on hepatocytes has also been associated with increased activation of AKT and ERK1/2 (Aviv et al., 2009; Gupta et al., 2010; Svegliati‐Baroni et al., 2011) in those cells.