Effects of short-term treatment with pravastatin on the hepatic synthesis of cholesterol and bile acids in gallstone patients.

HMG-CoA reductase inhibitors are now the therapy of choice in the treatment of hypercholesterolaemia. The effects of long-term treatment with these substances on plasma lipoproteins, cholesterol metabolism and biliary secretion of lipids have been extensively studied in humans. Much less is known about the effects of short-term treatment. The aim of this study was to determine the time course of the effects of HMG-CoA reductase inhibitors on plasma lipoprotein levels as well as cholesterol and bile acid synthesis in gallstone patients. Thirty-six patients undergoing elective cholecystectomy were included in the study. Except for the gallstone disease, these patients were otherwise healthy. Four groups of subjects were treated with the HMG-CoA reductase inhibitor pravastatin (Pravachol), 20 mg twice daily for 12, 24, 48 and 72 h preoperatively. Plasma lipoproteins and plasma levels of lathosterol and 7 alpha-hydroxy-4-cholesten-3-one were determined before initiation of pravastatin treatment and on the morning of the day of the operation, lathosterol reflecting hepatic HMG-CoA reductase activity and 7 alpha-hydroxy-4-cholesten-3-one the activity of cholesterol 7 alpha-hydroxylase, the rate-determining enzyme in bile acid synthesis. All treatment groups displayed a significant decrease in total cholesterol and low-density lipoprotein (LDL)-cholesterol, by about 12% and 17% respectively. Lathosterol was reduced by about 50% in all treatment groups. Of great interest was the finding that 7 alpha-hydroxy-4-cholesten-3-one was unaffected in all treatment groups. The results show that short-term pravastatin treatment in gallstone patients rapidly inhibits cholesterol synthesis and lowers plasma LDL-cholesterol levels without effects on bile acid synthesis.