The effect of conjugated linoleic acid isomers on fatty acid profiles of liver and adipose tissues and their conversion to isomers of 16:2 and 18:3 conjugated fatty acids in rats.
Conjugated linoleic acid (CLA) is a collective term that describes different isomers of linoleic acid with conjugated double bonds. Although the main dietary isomer is 9cis,11trans-18:2, which is present in dairy products and ruminant fat, the biological effects of CLA generally have been studied using mixtures in which the 9cis,11trans- and the 10trans,12cis-18:2 were present at similar levels. In the present work, we have studied the impact of each isomer (9cis,11 trans- and 10trans,12cis-18:2) given separately in the diet of rats for 6 wk. The 10trans,12cis-18:2 decreased the triacylglycerol content of the liver (-32%) and increased the 18:0 content at the expense of 18:1 n-9, suggesting an alteration of the delta9 desaturase activity, as was already demonstrated in vitro. This was not observed when the 9cis,11trans-18:2 was given in the diet. Moreover, the 10trans,12cis-18:2 induced an increase in the C22 polyunsaturated fatty acids in the liver lipids. The 10trans,12cis-18:2 was mainly metabolized into conjugated 16:2 and 18:3, which have been identified. The 9cis,11trans isomer was preferentially metabolized into a conjugated 20:3 isomer. Thus, the 9cis,11trans- and the 10trans,12cis-CLA isomers are metabolized differently and have distinct effects on the metabolism of polyunsaturated fatty acids in rat liver while altering liver triglyceride levels differentially.
Sébédio
J L
JL
INRA, Unité de Nutrition Lipidique, Dijon, France. sebedio@dijon.inra.fr
Angioni
E
E
Chardigny
J M
JM
Grégoire
S
S
Juanéda
P
P
Berdeaux
O
O
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005527:Food, Fortified; D007536:Isomerism; D008041:Linoleic Acids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D051381:Rats; D017208:Rats, Wistar
D005227:Fatty Acids; D008041:Linoleic Acids; D008055:Lipids