Effects of interleukin-15 on lipid oxidation: disposal of an oral [(14)C]-triolein load.
Interleukin 15 (IL-15) has previously been shown to have important effects on lipid metabolism in adipose tissue, particularly influencing the rate of the de novo fatty acid synthesis. The results presented here show that chronic administration to rats (100 microg/kg body weight) has important effects on the metabolic fate of an exogenous [(14)C]-triolein load, decreasing the incorporation of lipid into adipose tissue and significantly increasing the total (14)CO(2) formation from [(14)C]-triolein. Skeletal muscle and possibly liver seem to be the main organs involved in the action of IL-15 on lipid oxidation, since the presence of the cytokine in incubated EDL muscle with [(14)C]-palmitic acid increased (14)CO(2) formation by 39%. Concerning the mechanism, the results suggest that the transport of fatty acids into mitochondria could be involved in the action of IL-15 since the cytokine clearly increases the presence of L-CPT-I and CPT-II in liver tissue. In addition, IL-15 treatment resulted in a significant increment in the gene expression of PPARdelta, a transcription factor clearly related with lipid catabolism in many tissues. Altogether, the results presented here suggest that IL-15 alters exogenous lipid partitioning, limiting adipose tissue uptake and favouring oxidation.
Almendro
Vanessa
V
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
Busquets
Sílvia
S
Ametller
Elisabet
E
Carbó
Neus
N
Figueras
Maite
M
Fuster
Gemma
G
Argilés
Josep M
JM
López-Soriano
Francisco J
FJ
D000818:Animals; D019409:Interleukin-15 / Q000235:genetics / Q000494:pharmacology*; D008297:Male; D009928:Organ Specificity; D010084:Oxidation-Reduction; D047492:Peroxisome Proliferator-Activated Receptors / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014304:Triolein / Q000378:metabolism*
D019409:Interleukin-15; D047492:Peroxisome Proliferator-Activated Receptors; D014304:Triolein