Conjugated linoleic acid isomers in mitochondria: evidence for an alteration of fatty acid oxidation.
The beneficial effects exerted by low amounts of conjugated linoleic acids (CLA) suggest that CLA are maximally conserved and raise the question about their mitochondrial oxidizability. Cis-9,trans-11-C(18:2) (CLA1) and trans-10,cis-12-C(18:2) (CLA2) were compared to cis-9,cis-12-C(18:2) (linoleic acid; LA) and cis-9-C(16:1) (palmitoleic acid; PA), as substrates for total fatty acid (FA) oxidation and for the enzymatic steps required for the entry of FA into rat liver mitochondria. Oxygen consumption rate was lowest when CLA1 was used as a substrate with that on CLA2 being intermediate between it and the respiration on LA and PA. The order of the radiolabeled FA oxidation rate was PA >> LA > CLA2 > CLA1. Transesterification to acylcarnitines of the octadecadienoic acids were similar, while uptake across inner membranes of CLA1 and, to a lesser extent, of CLA2 was greater than that of LA or PA. Prior oxidation of CLA1 or CLA2 made re-isolated mitochondria much less capable of oxidising PA or LA under carnitine-dependent conditions, but without altering the carnitine-independent oxidation of octanoic acid. Therefore, the CLA studied appeared to be both poorly oxidizable and capable of interfering with the oxidation of usual FA at a step close to the beginning of the beta-oxidative cycle.
Demizieux
Laurent
L
UPRES Lipides et Nutrition EA2422, Faculté des Sciences Gabriel, Université de Bourgogne, 21000 Dijon, France.
Degrace
Pascal
P
Gresti
Joseph
J
Loreau
Olivier
O
Noël
Jean-Pierre
JP
Chardigny
Jean-Michel
JM
Sébédio
Jean-Louis
JL
Clouet
Pierre
P
D000818:Animals; D002210:Caprylates / Q000378:metabolism; D002333:Carnitine Acyltransferases / Q000378:metabolism; D003066:Coenzyme A Ligases / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D007536:Isomerism; D019787:Linoleic Acid / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D002210:Caprylates; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; C027369:octadecadienoic acid; D019787:Linoleic Acid; D002333:Carnitine Acyltransferases; D003066:Coenzyme A Ligases; C031492:octanoic acid