Notable batokines include fibroblast growth factor 21 (FGF21), which enhances glucose uptake and lipid oxidation [87,88], neuregulin 4 (NRG4), which protects against hepatic steatosis [89], and bone morphogenetic protein 8b (BMP8b), which enhances the thermogenic capacity [90]. This evidence concerns the gene NRG4 and fatty liver disease.