[Alterations of bile acid metabolism during treatment with chenodeoxycholic acid. Studies of the role of the appearance of ursodeoxycholic acid in the dissolution of gallstones (author's transl)].

Nine patients with radiolucent stones in the gallbladder were investigated before and during treatment with chenodeoxycholic acid (CDC). During treatment the biliary composition of bile acids changed considerably. Before the ingestion of CDC,bile acids consisted predominantly of cholic acid, deoxycholic acid and CDC; lithocholic acid was present in small amounts only. In the course of treatment CDC or this bile acid together with ursodeoxycholic acid (UDC) became the major biliary bile acid. The content of CDC increased from 47.5 +/- 4.21 to 79.2 +/- 6.37 SEM %, whereas that of UDC increased from 2.7 +/- 1.15 to 13.4 +/- 6.4%. The unsulfated lithocholic acid increased slightly from 0.7 +/- 0.22 to 2.7 +/- 0.41%. The bile acid pool expanded by an average of 130%. The degree of expansion of the pool varied considerably among the different patients. The largest increase in the pool size, however, occurred in the patients with the largest content of UDC in bile. Gallstone dissolution was observed in five patients. Among these five were those patients with the highest content of UDC, Corresponding 8.6, to 29.4 and 51.7%, respectively. These findings suggest that, in addition to CDC, UDC has a cholelitholytic effect in vivo. Of interest also was the observation that the patients in whom the size of the bile acid pool increased only very little showed no dissolution of gallstones. Both the stool weight and the fecal excretion of the isotopes, after the administration of radioactively labeled bile acids, increased only slightly during the treatment with CDC. The cholelitholytically efficacious dose of 20 mg/kg/day of CDC applied in this study appears to be useful in that 94% of it was abosrbed.