The effect of ursodeoxycholic acid on biliary bile acid composition in patients with cholesterol gallstone

To elucidate the role of conjugated biliary bile acids in gallstone dissolution, the acids in bile were determined by high-performance liquid chromatography before and after the treatment with ursodeoxycholic acid for 3-26 months in patients with gallstone. The stone-dissolving effect of ursodeoxycholic acid was confirmed in 7 of 10 patients and the lithogenic index lowered significantly after the treatment. The compositions of cholate, chenodeoxycholate and ursodeoxycholate were about 33, 45 and 4%, respectively, in the control and pre-treatment groups. In the post-treatment group, a markedly low value was observed in primary bile acids both glycine-conjugates and taurine-conjugates, especially in cholate, with a significantly high value of ursodeoxycholate (p less than 0.001) of both conjugates. On the other hand, no difference was observed in the composition of deoxycholate with significantly low percentage of taurine-conjugates compared with that in the pre-treatment group. The ratio of glycine- to taurine-conjugated bile acids showed a significantly higher value in the post-treatment group than in the pre-treatment group (p less than 0.001) and the control group (p less than 0.005). The bile specimens were measured concomitantly by gas-liquid chromatography and the results were compared with those of high-performance liquid chromatography. The mean value of total bile acids, the ratio of cholate to chenodeoxycholate and the ratio of glycine- to taurine-conjugated bile acids obtained by the former analysis procedure represented about 57, 80 and 115% of those of the latter. It is concluded that the high G/T value seems to have a role in the dissolution mechanism.