Mechanism of the lipid-lowering effect of ethyl all-cis-5,8,11,14,17-icosapentaenoate

Eur J Pharmacol. 1993 Jan 26;231(1):121-7. doi: 10.1016/0014-2999(93)90692-b.


The effect of highly purified ethyl all-cis-5,8,11,14,17-icosapentaenoate (EPA-E) on cholesterol metabolism in rats was examined to clarify the mechanism of its hypolipidemic action. Pretreatment with EPA-E reduced the increase in plasma radioactivity after oral administration of [14C]cholesterol. The conversion of [14C]3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) to [14C]mevalonic acid was significantly inhibited in liver microsomes obtained from rats treated with EPA-E. There was an increase in free cholesterol and a marked rise in the eicosapentaenoic acid (EPA) content of phospholipids in these microsomes. EPA-E restored the suppression of biliary secretion induced by feeding a casein-rich diet to bile duct-cannulated rats. Furthermore, when serum lipoprotein (d < 1.210) from rats given EPA-E was i.v. injected into normal rats, a more rapid elimination of cholesterol was observed as compared to that in rats injected with lipoprotein from EPA-E-untreated rats. This rapid clearance was found in the lipoprotein fractions of d < 1.006 and 1.006 < d < 1.063. These findings suggest that EPA-E has an inhibitory effect on intestinal cholesterol absorption and hepatic cholesterol biosynthesis, and an enhancing effect on hepatic biliary secretion. EPA-E would also seem to cause modification of serum lipoproteins, whereby their clearance from the serum is increased.

MeSH terms

  • Administration, Oral
  • Animals
  • Bile / metabolism
  • Cholesterol / blood*
  • Cholesterol / pharmacokinetics
  • Eicosapentaenoic Acid / analogs & derivatives*
  • Eicosapentaenoic Acid / pharmacology
  • Hydroxymethylglutaryl CoA Reductases / metabolism*
  • Intestinal Absorption / drug effects*
  • Lipoproteins / blood*
  • Lipoproteins / pharmacokinetics
  • Liver / metabolism
  • Male
  • Metabolic Clearance Rate / drug effects
  • Microsomes, Liver / enzymology*
  • Rats
  • Rats, Wistar


  • Lipoproteins
  • eicosapentaenoic acid ethyl ester
  • Cholesterol
  • Eicosapentaenoic Acid
  • Hydroxymethylglutaryl CoA Reductases