Effect of low levels of dietary fish oil on fatty acid desaturation and tissue fatty acids in obese and lean rats.
The effect of very low levels of dietary long-chain n-3 fatty acids on delta 6 desaturation of linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), and on delta 5 desaturation of dihomo-gamma-linolenic acid (20:3n-6), in liver microsomes and its influence on tissue fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing ca. 200 mg of long-chain polyunsaturated n-3 fatty acids per 100 g of diet were compared to those fed the same amount of alpha-linolenic acid. Low amounts of long-chain n-3 fatty acids greatly inhibited delta 6 desaturation of 18:2n-6 and delta 5 desaturation of 20:3n-6, while delta 6 desaturation of 18:3n-3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the biosynthesis of long-chain n-6 fatty acids was reflected in a decrease in arachidonic acid (20:4n-6) content of serum lipids when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids did not develop any decrease in 20:4n-6 during fish oil ingestion. Docosahexaenoic acid (22:6n-3), present in the dietary fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids.
Cao
J M
JM
Unité de Nutrition Cellulaire et Métabolique, Université de Bourgogne, Dijon, France.
Blond
J P
JP
Juaneda
P
P
Durand
G
G
Bézard
J
J
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000097:blood / Q000378:metabolism; D005227:Fatty Acids / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D007668:Kidney / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000187:drug effects*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011924:Rats, Zucker; D013045:Species Specificity
D004041:Dietary Fats; D005227:Fatty Acids; D005395:Fish Oils; D008041:Linoleic Acids; D004281:Docosahexaenoic Acids; D019787:Linoleic Acid