Muscle contractile activity increases fatty acid metabolism and transport and FAT/CD36.
We have examined whether 1) fatty acid (FA) uptake, 2) FA transporter expression, and 3) FA metabolism are increased when the oxidative capacity of skeletal muscle is increased. The oxidative capacities of red and white tibialis anterior and extensor digitorum longus muscles were increased via chronic stimulation (10 Hz, 24 h/day for 7 days). The contralateral muscles served as controls. After 7 days of increased muscle activity 1) palmitate uptake by giant sarcolemmal vesicles was increased twofold (P < 0.05), 2) the expression of FA translocase (FAT)/CD36 was increased at both the mRNA (3.2- to 10-fold) and protein (3.4-fold) levels, and 3) palmitate oxidation and esterification into triacylglycerols and phospholipids were increased 1.5-, 2.7-, and 1.7-fold, respectively (P < 0.05). These data show that when the oxidative capacity of muscle is increased, there is a parallel increase in the rate of FA transport and FA transporters at the sarcolemmal membrane, which is associated with the enhanced expression of the membrane transporter FAT/CD36.
Bonen
A
A
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1. abonen@healthy.uwaterloo.ca
Dyck
D J
DJ
Ibrahimi
A
A
Abumrad
N A
NA
D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism*; D004558:Electric Stimulation; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000502:physiology*; D027361:Organic Anion Transporters; D019308:Palmitic Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000378:metabolism; D014158:Transcription, Genetic
D018955:CD36 Antigens; D008562:Membrane Glycoproteins; D027361:Organic Anion Transporters; D019308:Palmitic Acid