FGF21 and steatosis: In terms of animal research, a mice experiment with utero exposure to PFOS has shown that significant hepatomegaly and steatosis occurred in the PFOS group of female rats, and increased triglyceride, total cholesterol, and LDL content and decreased HDL content were found in the liver of postnatal day 1 (PND1) mice; further analysis yielded significant changes in the expression of functional messenger RNAs for PND1 hepatocytochrome P4A14 (CYP4A14), CD36 (hepatic fatty acid uptake), apolipoprotein B100 (APOB), and fibroblast growth factor 21 (FGF21) [76].