Examination of carnitine palmitoyltransferase 1 abundance in white adipose tissue: implications in obesity research.
Carnitine palmitoyltransferase 1 (CPT1) is essential for the transport of long-chain fatty acids into the mitochondria for oxidation. Recently, it was reported that decreased CPT1b mRNA in adipose tissue was a contributing factor for obesity in rats. We therefore closely examined the expression level ofCpt1in adipose tissue from mice, rats, and humans.Cpt1ais the predominate isoform in adipose tissue from all three species. Rat white adipose tissue has a moderate amount ofCpt1bmRNA, but it is very minor compared withCpt1bexpression in muscle. Total CPT1 activity in adipose tissue is also minor relative to other tissues. BothCpt1aandCpt1bmRNA were increased in gonadal fat but not inguinal fat by diet-induced obesity in mice. We also measuredCPT1aandCPT1bexpression in subcutaneous adipose tissue from human subjects with a wide range of body mass indexes (BMIs). Interestingly,CPT1aexpression positively correlated with BMI (R= 0.46), but there was no correlation withCPT1b(R= 0.04). Our findings indicate that white adipose tissue fatty acid oxidation capacity is minor compared with that of metabolically active tissues. Furthermore, given the already low abundance ofCpt1bin white adipose tissue, it is unlikely that decreases in its expression can quantitatively decrease whole body energy expenditure enough to contribute to an obese phenotype.
Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.
Jaycob D
JD
Warfel
Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.
Bolormaa
B
Vandanmagsar
Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.
Olga S
OS
Dubuisson
Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.
Sydney M
SM
Hodgeson
Matrix Biology Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana; and.
Carrie M
CM
Elks
John S. McIlhenny Skeletal Muscle Physiology Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.
Eric
E
Ravussin
Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana; mynattrl@pbrc.edu.
Randall L
RL
Mynatt
D052436:Adipose Tissue, White / Q000201:enzymology*; D000328:Adult; D000368:Aged; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D009765:Obesity / Q000201:enzymology*; D009928:Organ Specificity; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D014018:Tissue Distribution
D002334:Carnitine O-Palmitoyltransferase
Cpt1a; Cpt1b; adipose tissue; lipid oxidation, obesity