ACOX1 and fatty liver disease: To investigate whether peroxisomal β-oxidation might play a role in regulating mitochondria FAO and inducing hepatic steatosis in the obese and diabetic animals, we used erucic acid (C22:1), a very long-chain fatty acid to specifically induce peroxisomal β-oxidation flux (25), and 10,12-tricosadiynoic acid (TDYA), a specific inhibitor for acyl-CoA oxidase-1 (ACOX1) to suppress peroxisomal β-oxidation (26).