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

S Neschen, I Moore, W Regittnig… - American Journal …, 2002 - journals.physiology.org
S Neschen, I Moore, W Regittnig, CL Yu, Y Wang, M Pypaert, KF Petersen, GI Shulman
American Journal of Physiology-Endocrinology and Metabolism, 2002journals.physiology.org
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 …
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-α ligands and thereby induce hepatic, but not intramuscular, peroxisome proliferation. In turn, an increased hepatic β-oxidative capacity results in lower hepatic triglyceride/diacylglycerol and intramyocellular triglyceride/fatty acyl-CoA content.
American Physiological Society