Effects of postmenopausal ethinylestradiol treatment on gallbladder bile.

Abstract Bile composition was studied in three postmenopausal women without evidence of gallstone disease during administration of 50 μg of ethinylestradiol daily. The treatment resulted in an increased fraction of cholesterol in gallbladder bile and a shift in the bile acid composition with decreased relative concentration of chenodeoxycholate and increased fraction of cholate. These changes in bile lipid composition might explain the higher incidence of gallstones in women treated with estrogens.