Contrasting effects of fish oil and safflower oil on hepatic peroxisomal and tissue lipid content

Am J Physiol Endocrinol Metab. 2002 Feb;282(2):E395-401. doi: 10.1152/ajpendo.00414.2001.

Abstract

To examine the mechanism by which fish oil protects against fat-induced insulin resistance, we studied the effects of control, fish oil, and safflower oil diets on peroxisomal content, fatty acyl-CoA, diacylglycerol, and ceramide content in rat liver and muscle. We found that, in contrast to control and safflower oil-fed rats, fish oil feeding induced a 150% increase in the abundance of peroxisomal acyl-CoA oxidase and 3-ketoacyl-CoA thiolase in liver but lacked similar effects in muscle. This was paralleled by an almost twofold increase in hepatic peroxisome content (both P < 0.002 vs. control and safflower). These changes in the fish oil-fed rats were associated with a more than twofold lower hepatic triglyceride/diacylglycerol, as well as intramuscular triglyceride/fatty acyl-CoA, content. In conclusion, these data strongly support the hypothesis that n-3 fatty acids protect against fat-induced insulin resistance by serving as peroxisome proliferator-activated receptor-alpha ligands and thereby induce hepatic, but not intramuscular, peroxisome proliferation. In turn, an increased hepatic beta-oxidative capacity results in lower hepatic triglyceride/diacylglycerol and intramyocellular triglyceride/fatty acyl-CoA content.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Ceramides / metabolism
  • Diglycerides / metabolism
  • Docosahexaenoic Acids / metabolism
  • Eicosapentaenoic Acid / metabolism
  • Enzymes / genetics
  • Enzymes / physiology
  • Fish Oils / pharmacology*
  • Lipid Metabolism*
  • Liver / drug effects*
  • Liver / metabolism*
  • Liver / ultrastructure
  • Male
  • Mitochondria, Liver / ultrastructure
  • Muscle, Skeletal / metabolism
  • Oxidation-Reduction
  • Peroxisomes / metabolism*
  • Peroxisomes / ultrastructure
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Safflower Oil / pharmacology*
  • Triglycerides / metabolism

Substances

  • Ceramides
  • Diglycerides
  • Enzymes
  • Fish Oils
  • RNA, Messenger
  • Triglycerides
  • Docosahexaenoic Acids
  • Safflower Oil
  • Eicosapentaenoic Acid