The pool size, half life, and daily production rate of
chenodeoxycholic acid (CDCA) was determined by the
isotope dilution method upon
intravenous injections of about 10 muCI OF 24-14C-CDCA in 7 patients with radiolucent
gallstones in functioning gallbladders, and 9 healthy controls. Bile was obtained by duodenal intubation. The method also allowed measurement of the CDCA percentage of total
bile acids (TBA) and an indirect calculation of the TBA pool size. The pool size and daily production rate of CDCA were slightly, but not significantly, diminished in the
gallstone patients. The half life of CDCA was almost equal in the 2 groups. The CDCA percentage of TBA was significantly higher in the
gallstone patients (0.02 less than P less than 0.05), and the TBA pool size was significantly reduced (P less than 0.01) in the
gallstone patients. It is concluded that the CDCA metabolism is similar to that of
cholic acid in
gallstone patients. Thus the formation of
gallstones is hardly due to specific alterations in CDCA metabolism, suspected on account of the specific cholelitholytic effect of CDCA ingestion. The significance of increased CDCA percentage in bile is discussed in relation to the results from other study groups, and it is pointed out that a relative increase in the bile content of dihydroxy
bile acids may lead to reduced
cholesterol holding capacity of bile, and thus favor the formation of
gallstones.