Olive oil feeding up-regulates uncoupling protein genes in rat brown adipose tissue and skeletal muscle.
BACKGROUND
Some nutrients, such as carotenoids, retinoic acid, and certain types of fatty acids, increase thermogenic capacity.


OBJECTIVE
The influence of 4 dietary lipid sources (olive oil, sunflower oil, palm oil, and beef tallow) on the content of uncoupling proteins 1, 2, and 3 (UCP1, UCP2, and UCP3) and their messenger RNA (mRNA) expression in several tissues of rats was compared.


METHODS
Wistar rats were randomly divided into 4 groups and fed ad libitum diets containing 40% of energy as fat. UCP1, UCP2, and UCP3 mRNA and protein were assessed by Northern blot and Western blot, respectively. Oxygen consumption in tissues was measured by polarography. Total-body oxygen consumption was assessed in an open-circuit chamber system. Circulating fuels (fatty acids and glucose) and hormones (triiodothyronine, thyroxine, corticosterone, and insulin) were measured.


RESULTS
Olive oil feeding induced the highest UCP1, UCP2, and UCP3 mRNA expression in interscapular brown adipose tissue. An analogous effect was observed in gastrocnemius muscle UCP3 mRNA. No significant differences were observed in perirenal white adipose tissue UCP2 mRNA. Changes in mRNAs were not accompanied by close changes in the protein content of UCPs and were not associated with changes in adipose tissue oxygen consumption. Nevertheless, total-body oxygen consumption was higher in rats fed olive oil than in those fed the other 3 diets. No significant differences were found in body and tissue weights or in serum indexes.


CONCLUSIONS
Olive oil induced an up-regulating effect on UCP mRNA that was probably not mediated by systemic metabolic changes, but rather related to a local effect on interscapular brown adipose tissue and skeletal muscle.
Rodríguez
Víctor M
VM
Department of Nutrition and Food Science, the University of País Vasco, Vitoria, Spain.
Portillo
María P
MP
Picó
Catalina
C
Macarulla
M Teresa
MT
Palou
Andreu
A
D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D004032:Diet; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D000069463:Olive Oil; D010101:Oxygen Consumption / Q000187:drug effects; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3; D015854:Up-Regulation / Q000187:drug effects*
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D000069463:Olive Oil; D010938:Plant Oils; D011506:Proteins; D012333:RNA, Messenger; C000604373:Ucp1 protein, rat; C000604391:Ucp2 protein, rat; C000604394:Ucp3 protein, rat; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3