The effects of
beta-muricholic acid and
hyocholic acid on
cholesterol cholelithiasis were examined in two animal models. The following experiments were carried out: A) In a
gallstone prevention study, prairie dogs were fed the lithogenic diet with or without 0.1% beta-muricholic or 0.1%
hyocholic acid for eight weeks. B) In a second prevention study, hamsters were fed the lithogenic diet with or without 0.1%
beta-muricholic acid or 0.1%
hyocholic acid for six weeks. C) In a
gallstone dissolution study, hamsters were fed the lithogenic diet for six weeks to induce stones; stone dissolution was examined during administration of a
cholesterol-free purified diet with or without 0.1%
beta-muricholic acid or 0.1%
hyocholic acid. In the prevention study in prairie dogs (A), both
bile acids failed to prevent stone formation, the
cholesterol saturation index of bile was 0.89 in the lithogenic controls, remained unchanged with
hyocholic acid and increased to 1.52 in the
beta-muricholic acid group. In the prevention study in hamsters (B),
beta-muricholic acid completely inhibited the
cholesterol cholelithiasis (0% stone incidence); the
cholesterol saturation index of bile was 1.78 (compared to lithogenic controls, 1.37).
Hyocholic acid reduced stone incidence to 16% with a
cholesterol saturation index of 0.98. In the dissolution study in hamsters (C), preexisting
cholesterol gallstones were not dissolved by either hydrophilic
bile acid after feeding these
bile acids for an additional six weeks; at the end of the experiment, the
cholesterol saturation indices were below unity.(ABSTRACT TRUNCATED AT 250 WORDS)