Ursodeoxycholic acid improves ethinyl estradiol-induced cholestasis in the rat.

The effect of oral chronic administration of ursodeoxycholic acid has been examined in rats with cholestasis induced by ethinyl estradiol. Ursodeoxycholic acid at the dose of 25 mg kg-1 per day during 4 days, did not improve the decrease in basal bile flow and bile acid secretion induced by ethinyl estradiol alone. In contrast, when ursodeoxycholic acid was given at the same dose during 10 days, basal bile flow was significantly improved and basal bile acid secretion was restored to control values. When ursodeoxycholic acid was given at the dose of 500 mg kg-1 per day, basal bile flow and bile acid output were not further improved. However, bile flow and bile acid output under taurocholate infusion were restored to control values. Bile of rats treated with ursodeoxycholic acid was enriched with this bile acid. These results show a significant improvement of ethinyl estradiol-induced cholestasis in rats after chronic administration of ursodeoxycholic acid and support the use of this bile acid in intrahepatic cholestasis in man.