Die Wirkung von Ursodeoxycholsäure auf die Cholesterin- und Gallensäurebiosynthese

Ursodeoxycholic acid (UDCA) decreases biliary secretion of
cholesterol and has therefore been used for the dissolution of
cholesterol gallstones. It remained unclear whether these changes
in biliary cholesterol excretion are associated with changes in
cholesterol synthesis and bile acid synthesis. The activities of
the rate-limiting enzymes of both, cholesterol and bile acid
synthesis, have been studied in normal subjects during 8-14 mg/kg
UDCA feeding. Moreover, lipoproteins and bile acids were measured.
Before, during, and after 40 days of UDCA ingestion,
7-alpha-hydroxy-4-cholesten-3-one in serum and urinary excretion of
mevalonic acid were determined. Ursodeoxycholic acid treatment
seems to not affect cholesterol synthesis in the liver, but does
increase bile acid synthesis after prolonged treatment. This may
attribute to homeostasis of cholesterol in the liver while
preventing an excess of cholesterol.