Wild type (WT) and SphK2−/− (KO) mice (male, 20-week old) were fed normal chow diet (ND; solid bar), high fat diet (HFD; checkered bar), or HFD containing 1% cholic acid (HFD+CA; shaded bar) for two weeks. (A) The mRNA levels of SphK2 in the liver of WT mice were determined by real time RT-PCR and normalized using GAPDH as internal control. (B) The protein expression levels of SphK2 in the liver of WT and SphK2−/− mice were determined by Western Blot analysis and normalized using β-tubulin as loading control. (C) The enzyme activities of SphK2 were measured using [γ32P]-ATP. *P<0.05, **P<0.01, statistical significance relative to control group.