Chronic leptin treatment normalizes basal glucose transport in a fiber type-specific manner in high-fat-fed rats.
The aim of this investigation was to determine if a high-fat diet impaired and subsequent leptin administration improved non-insulin-stimulated (basal) glucose transport in rodents. Twenty-four male Sprague Dawley rats were divided into 1 of 2 groups: (1) normal diet (control [CON], n = 8) or (2) high-fat diet (n = 16) and received standard rat chow or a high-fat diet, respectively, for 12 weeks. The high-fat diet animals were then further subdivided into high fat (HF) (n = 8) or high-fat-leptin (HF-LEP) (n = 8) groups. The HF-LEP animals were injected with leptin (10 mg leptin/kg/d), while the CON and HF animals received vehicle over a 12-day treatment period. Following the 12-day treatment period, all animals were subjected to hind limb perfusion to assess rates of basal skeletal muscle 3-O-methyl-D-glucose (3-MG) transport. Compared with the CON group, rates of 3-MG transport were reduced in the soleus (sol) and plantaris (plant) of the HF, but not the HF-LEP animals. Differences in skeletal muscle 3-MG transport could not be accounted for by an altered GLUT1 protein concentration. In contrast, a high-fat diet reduced and chronic leptin treatment normalized the skeletal muscle GLUT4 protein concentration. The results indicate that a high-fat diet reduces and subsequent leptin treatment improves basal skeletal muscle glucose transport in a fiber-type-specific manner, but these changes do not appear to be due to alterations in the GLUT1 protein concentration.
Yaspelkis
Ben B
BB
Exercise Biochemistry Laboratory, Department of Kinesiology, California State University Northridge, Northridge, CA 91330-8287, USA.
Saberi
Maziyar
M
Singh
Mohenish K
MK
Trevino
Beatriz
B
Smith
Toby L
TL
D019325:3-O-Methylglucose / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D006614:Hindlimb; D020738:Leptin / Q000008:administration & dosage*; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D013995:Time; D014280:Triglycerides / Q000378:metabolism
D004041:Dietary Fats; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D020738:Leptin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat; D014280:Triglycerides; D019325:3-O-Methylglucose; D005947:Glucose