Dietary Trans-Fatty Acids Alter Adipocyte Plasma Membrane Fatty Acid Composition and Insulin Sensitivity in Rats

Metabolism. 2005 Feb;54(2):240-6. doi: 10.1016/j.metabol.2004.08.019.

Abstract

The present study was designed to investigate the effects of dietary trans-fatty acids (TFA) present in Indian vanaspati (partially hydrogenated vegetable oils) in comparison with saturated fatty acids (SFA) on adipocyte plasma membrane fatty acid composition, fluidity, and insulin action. The effects of 3% energy (% en) TFA was studied at 2% and 4% en of linoleic acid (18:2 n-6). WNIN male weanling rats were divided into 4 groups and fed casein-based diet containing 10% groundnut oil control (CON), palmolein (SFA), blend of vanaspati and safflower oil (3% en TFA and 2% en 18:2 n-6, TFA-1), or blend of vanaspati and safflower oil (3% en TFA and 4% en 18:2 n-6, TFA-2) for 12 weeks. Compared with CON, rats fed TFA and SFA diets had high levels of fasting plasma insulin and triglycerides. Both TFA- and SFA-fed groups had low levels of arachidonic acid (20:4 n-6) in adipocyte plasma membrane phospholipids. However, adipocyte plasma membrane fluidity decreased only in TFA-fed rats. Norepinephrine-stimulated lipolysis was high, whereas the antilipolytic effect of insulin and insulin-stimulated glucose transport were low in the adipocytes of SFA- and TFA-fed rats. However, the extent of decrease in the antilipolytic effect of insulin and insulin-stimulated glucose transport was greater in TFA-fed rats. These findings suggest that diet providing approximately 10% en SFA (PUFA/SFA [P/S] ratio 0.2) decreased adipocyte insulin sensitivity in rats. In these diets, replacement of approximately 2% en SFA (16:0) and approximately 1% en monounsaturated fatty acid (18:1 cis) with TFA decreased adipocyte insulin sensitivity to a greater extent. However, increasing dietary 18:2 n-6 did not prevent or reduce the TFA-induced adipocyte insulin resistance.

MeSH terms

  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Adrenergic alpha-Agonists / pharmacology
  • Animals
  • Blood Glucose / metabolism
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Separation
  • Diet
  • Dietary Fats / pharmacology*
  • Fatty Acids / chemistry
  • Fatty Acids / metabolism
  • Glucose Tolerance Test
  • Hypoglycemic Agents / pharmacology
  • Insulin / pharmacology
  • Insulin Resistance / physiology*
  • Lipolysis / drug effects
  • Male
  • Membrane Fluidity / drug effects
  • Norepinephrine / pharmacology
  • Phospholipids / metabolism
  • Plant Oils / chemistry
  • Plant Oils / pharmacology*
  • Rats
  • Trans Fatty Acids / pharmacology*

Substances

  • Adrenergic alpha-Agonists
  • Blood Glucose
  • Dietary Fats
  • Fatty Acids
  • Hypoglycemic Agents
  • Insulin
  • Phospholipids
  • Plant Oils
  • Trans Fatty Acids
  • Norepinephrine