Capsiate administration results in an uncoupling protein-3 downregulation, an enhanced muscle oxidative capacity and a decreased abdominal fat content in vivo.
OBJECTIVE
The involvement of skeletal muscle mitochondrial uncoupling protein-3 (UCP3) in the control of energy expenditure in skeletal muscle and at the whole-body level is still a matter of debate. We previously reported that UCP3 downregulation is linked to an enhanced mitochondrial energy metabolism in rat skeletal muscle as a result of acute capsiate treatment. Here, we aimed at investigating noninvasively the effects of chronic capsiate ingestion on metabolic changes occurring in exercising gastrocnemius muscle and at the whole-body level.


METHODS
We used an original experimental setup allowing a complete noninvasive investigation of gastrocnemius muscle function in situ using 31-phosphorus magnetic resonance spectroscopy. Whole-body fat composition was determined using magnetic resonance imaging and UCP3 gene expression was measured by quantitative real-time RT-PCR analysis.


RESULTS
We found that a 14-day daily administration of capsiate (100 mg kg(-1) body weight) reduced UCP3 gene expression and increased phosphocreatine level at baseline and during the stimulation period in gastrocnemius muscle. During muscle stimulation, pH(i) showed a larger alkalosis in the capsiate group suggesting a lower glycolysis and a compensatory higher aerobic contribution to ATP production. Although the capsiate-treated rats were hyperphagic as compared to control animals, they showed a lower weight gain coupled to a decreased abdominal fat content.


CONCLUSIONS
Overall, our data indicated that capsiate administration contributes to the enhancement of aerobic ATP production and the reduction of body fat content coupled to a UCP3 gene downregulation.
Faraut
B
B
Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS 6612, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille Cedex 5, France. brice.faraut@medecine.univ-mrs.fr
Giannesini
B
B
Matarazzo
V
V
Le Fur
Y
Y
Rougon
G
G
Cozzone
P J
PJ
Bendahan
D
D
D050153:Abdominal Fat / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D015536:Down-Regulation; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D007473:Ion Channels / Q000378:metabolism*; D008931:Mitochondria, Muscle / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D051381:Rats; D014475:Uncoupling Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000071247:Uncoupling Protein 3
D007473:Ion Channels; D024101:Mitochondrial Proteins; C000604394:Ucp3 protein, rat; D014475:Uncoupling Agents; D000071247:Uncoupling Protein 3; C470213:capsiate; D002211:Capsaicin