Objective    To investigate the expressions of farnesoid X receptor (FXR) and its target gene cholesterol-7α-hydroxylase (CYP7A1) in liver of pregnant rats with intrahepatic cholestasis

and to explore the mechanism of intrahepatic cholestasis of pregnancy (ICP).      Methods    Thirty SD rats at gestation day 15 were randomly assigned to receive isotonic Na chloride (NS) and estradiol benzoate (EB) for 5 d. Blood (2 ml) was taken before and at the end of 5-day administration to measure the levels of ALT

AST

ALP

TBA

and the liver of pregnant rats after sacrifice were taken to observe morphologic changes. The mRNA and protein expressions of FXR and CYP7A1 in liver were determined by RT-PCR and Western blotting.      Results    The serum levels of ALT

AST

ALP

TBA in EB rats increased significantly (P0.01)

and the pathological changes of EB rats proved intrahepatic cholestasis. The mRNA and protein expressions of FXR and CYP7A1 were significantly higher in EB rats than NS rats (P0.01).      Conclusion    Estradiol benzoate is the best candidate for inducing rat model of ICP. The mRNA and protein expressions of FXR and CYP7A1 in liver were increased

resulting in increased synthesis of bile acids

which may be one of the mechanisms of ICP.