Differential effects of coconut oil- and fish oil-enriched diets on tricarboxylate carrier in rat liver mitochondria.
The mitochondrial tricarboxylate carrier (TCC) plays an important role in lipogenesis being TCC-responsible for the efflux from the mitochondria to the cytosol of acetyl-CoA, the primer for fatty acid synthesis. In this study, we investigated the effects of two high-fat diets with different fatty acid composition on the hepatic TCC activity. Rats were fed for 3 weeks on a basal diet supplemented with 15% of either coconut oil (CO), abundant in medium-chain saturated fatty acids, or fish oil (FO), rich in n-3 polyunsaturated fatty acids. Mitochondrial fatty acid composition was differently influenced by the dietary treatments, while no appreciable change in phospholipid composition and cholesterol level was observed. Compared with CO, the TCC activity was markedly decreased in liver mitochondria from FO-fed rats; kinetic analysis of the carrier revealed a decrease of the Vmax, with no change of the Km. No difference in the Arrhenius plot between the two groups was observed. Interestingly, the carrier protein level and the corresponding mRNA abundance decreased following FO treatment. These data indicate that FO administration markedly decreased the TCC activity as compared with CO. This effect is most likely due to a reduced gene expression of the carrier protein.
Giudetti
Anna Maria
AM
Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Laboratorio di Biochimica, Università di Lecce, Via Prov.le Lecce-Monteroni, I-73100 Lecce, Italy.
Sabetta
Simona
S
di Summa
Roberta
R
Leo
Monica
M
Damiano
Fabrizio
F
Siculella
Luisa
L
Gnoni
Gabriele V
GV
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism / Q000494:pharmacology; D000074263:Coconut Oil; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D002352:Carrier Proteins; D004041:Dietary Fats; D005395:Fish Oils; D010743:Phospholipids; D010938:Plant Oils; D012333:RNA, Messenger; C020723:citrate-binding transport protein; D019343:Citric Acid; D002784:Cholesterol; D000074263:Coconut Oil