Muscle glucose transport, GLUT-4 content, and degree of exercise training in obese Zucker rats.
The effects of high (HI)- and low (LI)-intensity exercise training were examined on insulin-stimulated 3-O-methyl-D-glucose (3-MG) transport and concentration of insulin-regulatable glucose transporter protein (GLUT-4) in the red (fast-twitch oxidative) and white (fast-twitch glycolytic) quadriceps of the obese Zucker rat. Sedentary obese (SED) and lean (LN) Zucker rats were used as controls. 3-MG transport was determined during hindlimb perfusion in the presence of 8 mM 3-MG, 2 mM mannitol, 0.3 mM pyruvate, and 0.5 mU/ml insulin. HI and LI rats displayed greater rates of red quadriceps 3-MG transport and GLUT-4 concentrations than SED rats. No significant differences in rates of 3-MG transport or GLUT-4 concentrations were observed in the red quadriceps of HI and LI rats. There were no differences found in the rates of 3-MG transport in the white quadriceps of HI, LI, and SED rats although the difference between the HI and SED rats approached significance (P < 0.07). The GLUT-4 concentration and citrate synthase activity of HI rats were significantly greater than SED rats. The 3-MG transport rates of LN rats were twofold greater than SED rats regardless of fiber type, but a difference in GLUT-4 content between the LN and SED rats was observed only in the white quadriceps. GLUT-4 content of the obese rats was significantly correlated with citrate synthase activity (r = 0.93) and 3-MG transport (r = 0.82).(ABSTRACT TRUNCATED AT 250 WORDS)
Banks
E A
EA
Department of Kinesiology, University of Texas, Austin 78712.
Brozinick
J T
JT
Yaspelkis
B B
BB
Kang
H Y
HY
Ivy
J L
JL
D019325:3-O-Methylglucose; D000818:Animals; D001692:Biological Transport; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000493:pharmacokinetics*; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology; D008757:Methylglucosides / Q000493:pharmacokinetics; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D009132:Muscles / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D005082:Physical Exertion; D051381:Rats; D011924:Rats, Zucker
D051275:Glucose Transporter Type 4; D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D019325:3-O-Methylglucose; D002950:Citrate (si)-Synthase; D005947:Glucose