The effect of creatine supplementation on glucose uptake in rat skeletal muscle

Life Sciences ◽  
2002 ◽  
Vol 71 (15) ◽  
pp. 1731-1737 ◽  
Author(s):  
John C Young ◽  
Robert E Young
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Creatine Supplementation ◽  
Rat Skeletal Muscle

Impaired plasma FFA oxidation imposed by extreme CHO deficiency in contracting rat skeletal muscle

1994 ◽  
Vol 77 (2) ◽  
pp. 517-525 ◽  
Author(s):  
L. P. Turcotte ◽  
P. J. Hespel ◽  
T. E. Graham ◽  
E. A. Richter
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Glucose Uptake ◽  
Swimming Exercise ◽  
Rat Skeletal Muscle ◽  
Palmitate Oxidation ◽  
Plasma Ffa ◽  
Ffa Metabolism ◽  
Palmitate Uptake

The extent to which carbohydrate (CHO) availability affects free fatty acid (FFA) metabolism in contracting skeletal muscle is not well characterized. To study this question, rats were depleted of glycogen by swimming exercise and lard feeding 24 h before perfusion of their isolated hindquarters. After 20 min of preperfusion with a medium containing no glucose, palmitate (600 or 2,000 microM), and [1–14C]palmitate, flow was restricted to one hindlimb, which was electrically stimulated for 2 min to further deplete muscles of glycogen. After 2 min of recovery, glucose was added to the perfusate at final concentrations of 0, 6, or 20 mM, and after another 3 min muscles were stimulated for 30 min. At 6 and 2,000 microM palmitate, glucose uptake after 30 min of stimulation averaged 23.5 +/- 9.3 and 45.9 +/- 10.6 mumol.g-1.h-1 with 6 and 20 mM glucose, respectively. At 6 and 2,000 microM palmitate, palmitate uptake was lower (30–37%, P < 0.05) with 0 than with 6 or 20 mM glucose. At 600 microM palmitate, percent palmitate oxidation was higher (27%, P < 0.05) with 0 than with 6 or 20 mM glucose, resulting in similar total palmitate oxidation with the three glucose concentrations (0.28 +/- 0.01 mumol.g-1.h-1). At 2,000 microM palmitate, percent palmitate oxidation was not significantly different among glucose concentrations, resulting in a significantly lower rate of palmitate oxidation with 0 (0.62 +/- 0.18 mumol.g-1.h-1) than with 6 or 20 mM glucose (0.77 +/- 0.25 and 0.78 +/- 0.20 mumol.g-1.h-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

AMP-activated protein kinase activity and glucose uptake in rat skeletal muscle

2001 ◽  
Vol 280 (5) ◽  
pp. E677-E684 ◽  
Author(s):  
Nicolas Musi ◽  
Tatsuya Hayashi ◽  
Nobuharu Fujii ◽  
Michael F. Hirshman ◽  
Lee A. Witters ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Muscle Contractions ◽  
Treadmill Running ◽  
Dependent Manner ◽  
Rat Skeletal Muscle ◽  
Amp Activated Protein Kinase ◽  
Dose Dependent

The AMP-activated protein kinase (AMPK) has been hypothesized to mediate contraction and 5-aminoimidazole-4-carboxamide 1-β-d-ribonucleoside (AICAR)-induced increases in glucose uptake in skeletal muscle. The purpose of the current study was to determine whether treadmill exercise and isolated muscle contractions in rat skeletal muscle increase the activity of the AMPKα1 and AMPKα2 catalytic subunits in a dose-dependent manner and to evaluate the effects of the putative AMPK inhibitors adenine 9-β-d-arabinofuranoside (ara-A), 8-bromo-AMP, and iodotubercidin on AMPK activity and 3- O-methyl-d-glucose (3-MG) uptake. There were dose-dependent increases in AMPKα2 activity and 3-MG uptake in rat epitrochlearis muscles with treadmill running exercise but no effect of exercise on AMPKα1 activity. Tetanic contractions of isolated epitrochlearis muscles in vitro significantly increased the activity of both AMPK isoforms in a dose-dependent manner and at a similar rate compared with increases in 3-MG uptake. In isolated muscles, the putative AMPK inhibitors ara-A, 8-bromo-AMP, and iodotubercidin fully inhibited AICAR-stimulated AMPKα2 activity and 3-MG uptake but had little effect on AMPKα1 activity. In contrast, these compounds had absent or minimal effects on contraction-stimulated AMPKα1 and -α2 activity and 3-MG uptake. Although the AMPKα1 and -α2 isoforms are activated during tetanic muscle contractions in vitro, in fast-glycolytic fibers, the activation of AMPKα2-containing complexes may be more important in regulating exercise-mediated skeletal muscle metabolism in vivo. Development of new compounds will be required to study contraction regulation of AMPK by pharmacological inhibition.

Persistent increase in glucose uptake by rat skeletal muscle following exercise

1981 ◽  
Vol 241 (5) ◽  
pp. C200-C203 ◽  
Author(s):  
J. L. Ivy ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Muscle Glycogen ◽  
Glycogen Synthesis ◽  
Exercise Stress ◽  
Rat Skeletal Muscle ◽  
Major Pathway ◽  
Glycogen Accumulation ◽  
Hindlimb Muscles ◽  
Muscle Glycogen Concentration

The effect of a bout of exercise on glucose uptake and glycogen synthesis in skeletal muscle was examined using a perfused rat hindlimb preparation. Rats were subjected to a bout of swimming. The exercise stress was moderate as reflected in a reduction of muscle glycogen concentration of only 50%. Glucose uptake and glycogen synthesis were measured in perfused hindlimb muscles for a 30-min period beginning approximately 60 min following the exercise. The rate of glucose uptake in the absence of insulin was 10-fold higher in hindlimbs of exercised animals than in the controls. The rate of glucose uptake was also higher in exercised than in control muscles in the presence of 50 microunits/ml or 10 mU/ml of insulin, but these differences were smaller than that found in the absence of insulin. Conversion to glycogen was the major pathway for disposal of the glucose taken up by muscle. The rate of glycogen accumulation in the exercised plantaris muscles was greater than in the control muscles both in the absence and presence of insulin.

scholarly journals The effect of insulin-like growth factor II on glucose uptake and metabolism in rat skeletal muscle in vitro

1992 ◽  
Vol 286 (2) ◽  
pp. 561-565 ◽  
Author(s):  
S J Bevan ◽  
M Parry-Billings ◽  
E Opara ◽  
C T Liu ◽  
D B Dunger ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Glucose Uptake ◽  
Glycogen Synthesis ◽  
Insulin Like Growth Factor ◽  
Rat Skeletal Muscle ◽  
Factor Ii ◽  
Igf Binding ◽  
Uptake And Metabolism

The effect of insulin-like growth factor II (IGF II) on the rates of lactate formation, glycogen synthesis and glucose transport in the presence of a range of concentrations of insulin were investigated using an isolated preparation of rat skeletal muscle. IGF II, at a concentration of 65 ng/ml, caused a small but significant increase in the rates of these processes at a basal physiological insulin concentration (10 muunits/ml), but was without effect in the presence of 1, 100, 1000 or 10,000 muunits of insulin/ml. Hence IGF II increased the insulin sensitivity of this tissue. This effect was removed if the incubation medium was supplemented with an equimolar concentration of IGF binding protein 1 (BP1). It is suggested that changes in the concentration of IGF II and/or BP1 may regulate glucose uptake and metabolism in skeletal muscle and have physiological significance in the control of blood glucose level.

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