Effect of lipid content of diet on cholesterol content and cholesterogenic enzymes of European eel liver.

The effect of dietary lipid levels on the levels of cholesterol and the activities of the major cholesterogenic enzymes of the liver has been studied in the European eel. An increase in hepatic total cholesterol was observed when the dietary lipid levels increased from 12 to 20%, while protein levels were maintained at 30%. This change paralleled an increase in mevalonate 5-pyrophosphate decarboxylase activity, while 3-hydroxy-3-methylglutaryl-CoA reductase mevalonate kinase and mevalonate 5-phosphate kinase were not affected by changes in diet composition. These results suggest that the decarboxylase may be a rate-limiting enzyme in cholesterogenesis in eel liver.