Effect of dietary n-3 and n-6 fatty acids on fatty acid desaturation in rat liver

Biochim Biophys Acta. 1991 Feb 26;1082(1):57-62. doi: 10.1016/0005-2760(91)90299-w.


To study the effect of high-fat diets with varying contents of n-3 and n-6 fatty acids on the metabolism of essential fatty acids, the rat liver microsomal fatty acid desaturases were measured. The rats were fed for 3 weeks with diets high in linseed oil (18:3(n-3)), sunflower seed oil (18:2(n-6)) or fish oil (20:5(n-3) and 22:6(n-3)) (20%, w/w) using pellet fed rats as a reference. The delta 6-desaturase using 18:2(n-6) or 18:3(n-3) as substrates was stimulated 1.5-2.5-fold by linseed or sunflower seed oil, compared to the pellet reference. The delta 5-desaturase was stimulated 3.5-fold with linseed oil and 2.5-fold with sunflower seed oil, while the delta 9-desaturase was inhibited by all the high-fat diets. The delta 6-, 5- and 9-desaturase activities were in all cases considerably reduced with fish oil as compared to linseed and sunflower seed oil diets. With pellet fed rats the rates were highest for delta 9-desaturation and in decreasing order lower for delta 5-desaturation, delta 6-desaturation with 18:3 (n-3) as substrate and finally delta 6-Desaturation with 18:2(n-6) as substrate. The content of 20:4(n-6) in liver phospholipids increased with the diets rich in 18:2(n-6), and was reduced for the fish oil diet enriched in 20:5 and 22:6(n-3) fatty acids. The amount of 20:5(n-3) in phospholipids was as high with linseed oil diet as with the fish oil diet, while the 22:6(n-3) content was only increased with the fish oil diet.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dietary Fats, Unsaturated / administration & dosage
  • Dietary Fats, Unsaturated / pharmacology*
  • Fatty Acid Desaturases / metabolism*
  • Fatty Acids / metabolism
  • Fish Oils / administration & dosage
  • Fish Oils / pharmacology
  • Linolenic Acids / metabolism
  • Linseed Oil / administration & dosage
  • Linseed Oil / pharmacology
  • Liver / metabolism
  • Male
  • Microsomes, Liver / enzymology*
  • Phospholipids / metabolism
  • Plant Oils / administration & dosage
  • Plant Oils / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Sunflower Oil


  • Dietary Fats, Unsaturated
  • Fatty Acids
  • Fish Oils
  • Linolenic Acids
  • Phospholipids
  • Plant Oils
  • Sunflower Oil
  • Linseed Oil
  • Fatty Acid Desaturases