Investigation of the expression and localization of glucose transporter 4 and fatty acid translocase/CD36 in equine skeletal muscle.
OBJECTIVE
To investigate the expression and localization of glucose transporter 4 (GLUT4) and fatty acid translocase (FAT/CD36) in equine skeletal muscle.


METHODS
Muscle biopsy specimens obtained from 5 healthy Dutch Warmblood horses.


METHODS
Percutaneous biopsy specimens were obtained from the vastus lateralis, pectoralis descendens, and triceps brachii muscles. Cryosections were stained with combinations of GLUT4 and myosin heavy chain (MHC) specific antibodies or FAT/CD36 and MHC antibodies to assess the fiber specific expression of GLUT4 and FAT/CD36 in equine skeletal muscle via indirect immunofluorescent microscopy.


RESULTS
Immunofluorescent staining revealed that GLUT4 was predominantly expressed in the cytosol of fast type 2B fibers of equine skeletal muscle, although several type 1 fibers in the vastus lateralis muscle were positive for GLUT4. In all muscle fibers examined microscopically, FAT/CD36 was strongly expressed in the sarcolemma and capillaries. Type 1 muscle fibers also expressed small intracellular amounts of FAT/CD36, but no intracellular FAT/CD36 expression was detected in type 2 fibers.


CONCLUSIONS
In equine skeletal muscle, GLUT4 and FAT/CD36 are expressed in a fiber type selective manner.
van Dam
Klien G
KG
Department of Equine Sciences (Medicine Section), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 16, NL-3584 CM Utrecht, The Netherlands.
van Breda
Eric
E
Schaart
Gert
G
van Ginneken
Mireille M E
MM
Wijnberg
Inge D
ID
de Graaf-Roelfsema
Ellen
E
van der Kolk
Johannes H
JH
Keizer
Hans A
HA
D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D001706:Biopsy; D018955:CD36 Antigens / Q000378:metabolism*; D002196:Capillaries / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D051275:Glucose Transporter Type 4; D006736:Horses / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism
D018955:CD36 Antigens; D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins