Effect of chenodeoxycholic acid on the alterations of biliary lipid secretion induced by ethynylestradiol in the rat.

The role of chenodeoxycholic acid (CDCA) in modifying the biliary secretory alterations induced by ethynylestradiol (EE) was evaluated in male Sprague-Dawley rats. Bile flow and bile acid output were both decreased in rats given EE either alone or with CDCA (EE + CDCA) whereas cholesterol output showed a significant decrease only in animals given the combined treatment. The output of phospholipids remained unchanged in all groups. As a result the lithogenic index was significantly decreased in EE + CDCA-treated rats. In urine, the total bile acid excretion was significantly increased in EE + CDCA-treated animals. The data indicate that in the rat, biliary secretory failure induced by EE is not modified by CDCA, but that CDCA may prevent the increase of biliary cholesterol saturation caused by EE.