Effects of estrone on the biliary excretion of xenobiotics.

The effect on the biliary excretion of exogenous organic anions and the mechanism of action of estrone has been studied. Female Wistar rats weighing 180-200 g were pretreated with estrone (2.5 mg/kg ip daily for 4 days). This produced a significant decrease in the biliary flow and biliary excretion of bromcresol green and amaranth. Administration of taurocholate did not abolish the depressing effect of estrone; however, phenobarbital given in combination with estrone decreased or prevented the effects of estrone on the biliary excretion rate of bromcresol green and amaranth. These results indicate that changes in the bile salt independent fraction might be responsible for the effects of estrone on the biliary flow and biliary excretion of xenobiotics.