Hepatic transport of sulfated and nonsulfated bile acids in the rat following relief of bile duct obstruction.

The effect of bile duct ligation for 5 days on the hepatic transport of sulfated and nonsulfated bile acids was studied. Tracer doses of radioactive bile acids [3H]taurochenodeoxycholate-3-sulfate [3H]chenodeoxycholate-3-sulfate, [3H]taurochenodeoxycholic acid and [14C]taurocholic acid were injected 90 min after relief of obstruction when the plasma total bile acid concentration had reverted to normal. Plasma clearance and biliary excretion of sulfated bile acids were lower than those of nonsulfated bile acids, particularly in the cholestatic rats (p less than 0.02). For each bile acid, hepatic transport in the cholestatic rats was significantly reduced compared with the control rats. [3H]Chenodeoxycholate-3-sulfate and [3H]taurochenodeoxycholic acid were partially metabolized to [3H]taurochenodeoxycholate-3-sulfate prior to biliary excretion. This data suggests that the hepatic transport system for sulfated bile acids is less efficient and more easily impaired by cholestasis than that for nonsulfated bile acids.