Effect of impaired glucose uptake on postexercise glycogen repletion in skeletal muscles of insulin-treated streptozotocin-diabetic fasted rats

Ferreira, Luis D.; Xu, Dan; Palmer, T.N.; Fournier, Paul A.

doi:10.1016/j.metabol.2005.04.006

Cited by 6 publications

(5 citation statements)

References 33 publications

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“…It is possible, however, that the lack of difference in glycogen levels in the white gastrocnemius muscle as the post-active recovery period progresses is due to a lack of statistical power as suggested by the 60 min glycogen bars appearing to be higher than the 30-min bars. Overall, these findings are consistent with those of earlier studies from our laboratory on the importance of both enzymes in the regulation of glycogen synthesis without food after an intense bout of exercise (11,18,19,48). Arguably, given the many factors that could play a role in controlling the rate of glycogen synthesis, such as the many phosphorylation sites and kinases affecting the activity and intracellular localization of glycogen synthase (16,46,49), glucose transport activation post-intense exercise (18), and the possible increased blood flow to actively recovering muscle, further work is required to elucidate the relative importance of these factors in the regulation of glycogen synthesis after active recovery in FOG and FG muscle fibers.…”

Section: Discussionsupporting

confidence: 92%

“…This was illustrated for the first time in one of our recent studies in which we showed that insulintreated streptozotocin-diabetes in fasted rats recovering from a sprint is without any effect on both the activation levels of glycogen synthase and muscle glycogen repletion, despite a markedly reduced activation of glucose transport rate (Ͼ3-fold lesser activation in some muscles, see Ref 19). Although this could be taken as evidence that glucose transport plays little role in controlling the rate of muscle glycogen synthesis under these conditions, glucose transport could still play some role if one assumes that the absence of inhibition of glycogen synthesis in streptozotocin-diabetic rats is due to a compensatory increase in the contribution of MLG (19). Until appropriate methodologies are introduced to measure precisely the contribution of MLG in vivo, any changes in glucose transport activity in FG and FOG fibers recovering from intense contraction while lactate levels are elevated will inform us little about its importance in the regulation of glycogen synthesis.…”

Section: Discussionmentioning

confidence: 99%

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Fiber-specific responses of muscle glycogen repletion in fasted rats physically active during recovery from high-intensity physical exertion

Raja

Bräu²,

Palmer³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Mild physical activity performed immediately after a bout of intense exercise in fasting humans results in net glycogen breakdown in their slow oxidative (SO) muscle fibers and glycogen repletion in their fast twitch (FT) fibers. Because several animal species carry a low proportion of SO fibers, it is unclear whether they can also replenish glycogen in their FT fibers under these conditions. Given that most skeletal muscles in rats are poor in SO fibers (<5%), this issue was examined using groups of 24-h fasted Wistar rats (n=10) that swam for 3 min at high intensity with a 10% weight followed by either a 60-min rest (passive recovery, PR) or a 30-min swim with a 0.5% weight (active recovery, AR) preceding a 30-min rest. The 3-min sprint caused 61-79% glycogen fall across the muscles examined, but not in the soleus (SOL). Glycogen repletion during AR without food was similar to PR in the white gastrocnemius (WG), where glycogen increased by 71%, and less than PR in both the red and mixed gastrocnemius (RG, MG). Glycogen fell by 26% during AR in the SOL. Following AR, glycogen increased by 36%, 87%, and 37% in the SOL, RG, and MG, respectively, and this was accompanied by the sustained activation of glycogen synthase and inhibition of glycogen phosphorylase in the RG and MG. These results suggest that mammals with a low proportion of SO fibers can also replenish the glycogen stores of their FT fibers under extreme conditions combining physical activity and fasting.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Fiber-specific responses of muscle glycogen repletion in fasted rats physically active during recovery from high-intensity physical exertion

Raja

Bräu²,

Palmer³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Besides the TA, other rodent muscles are also known to display a pronounced regionalization of their different fiber types. For example, rat gastrocnemius muscle is often analyzed by separating the "white" (glycolytic) part from the "red" (mixed or oxidative) part (20). To our knowledge, 1 H MRS has not been used to study IMCL content in rat gastrocnemius muscle.…”

Section: Discussionmentioning

confidence: 99%

Regional variations in intramyocellular lipid concentration correlate with muscle fiber type distribution in rat tibialis anterior muscle

Feyter

Schaart

Hesselink

et al. 2006

Magnetic Resonance in Med

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1 1 H MR spectroscopy (MRS) has proved to be a valuable noninvasive tool to measure intramyocellular lipids (IMCL) in research focused on insulin resistance and type II diabetes in both humans and rodents. An important determinant of IMCL is the muscle fiber type, since oxidative type I fibers can contain up to three times more IMCL than glycolytic type II muscle fibers. Because these different muscle fiber types are inhomogeneously distributed in rodent muscle, in the present study we investigated the distribution of IMCL within the rat tibialis anterior muscle (TA) in vivo using single-voxel 1 H MRS along with the muscle fiber distribution in the TA ex vivo determined from immunohistological assays. IMCL levels in the TA differed by up to a factor of 3 depending on the position of the voxel. Skeletal muscle insulin resistance is one of the earliest detectable aberrations in and a predisposing factor for the development of type II diabetes. Increased content of intramyocellular lipids (IMCL) has been closely associated with decreased whole-body and skeletal muscle insulin sensitivity in both healthy and diabetic humans, as well as in animals (reviewed in Ref. 1). IMCL itself probably does not interfere with the insulin signaling pathway directly; rather, it is considered a surrogate marker of lipid metabolites, such as long chain acyl-CoA, diacylglycerol, and ceramides, that are likely to induce defects in the insulin signaling cascade (2). The good correlation of IMCL with insulin sensitivity led to the suggestion that IMCL could be used as a biomarker for insulin resistance in rat models (3).Skeletal muscle stores lipids not only intracellularly, but also extracellularly within interstitial adipocytes. Lipid extraction analysis of muscle biopsy samples therefore cannot differentiate between IMCL and extramyocellular lipids (EMCL) and hence may overestimate the actual IMCL content (1). The discovery that IMCL and EMCL resonate at different frequencies in the 1 H MR spectrum of human skeletal muscle was an important methodological advance in the study of skeletal muscle lipid metabolism (4). The resonance at 1.28 ppm is independent of the angle between the muscle fibers and the static magnetic field, and therefore is attributed to the CH 2 groups of IMCL because IMCL is dispersed as spherical droplets within the muscle cells. The other lipid CH 2 peak shifts with the angle between the muscle fibers and the field, and is therefore attributed to EMCL, which supposedly is arranged in a sheet-like manner along the muscle fibers. The largest chemical shift difference between the two peaks is 0.2 ppm, which is obtained when the muscle fibers are aligned parallel with the magnetic field (5). Since 1 H MRS is a noninvasive method, it allows repetitive analysis of IMCL in the same area. Thus, 1 H MRS-based IMCL measures are especially useful for determining IMCL levels in human studies, as well as for animal intervention and longitudinal studies.Using 1 H MRS, Neumann-Haefelin et al. (6) showed that the IMCL content in ...

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“…The influx of glucose in skeletal muscle depends on insulin (Bishop 1976). Also, the replenishment of muscle glycogen stores from glucose requires the activation of glucose transport (Ferraira et al 2005). In this situation, SS mitochondria are also response for propagation of insulin signaling in muscle cells, because the function of SS mitochondria for membrane-related processes in muscles is clearly relevant to insulin action (Hood 2001).…”

Section: Discussionmentioning

confidence: 99%

Acute toxicity of boric acid on energy metabolism of the breast muscle in broiler chickens

Geyikoğglu

Türkez

2007

Biologia

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Short-and long-term oral exposures to boric acid (BA) in laboratory animals and birds caused toxic effects. However, the toxicity data on adult poultry skeletal muscles of BA was not documented with metabolic studies. Livability, weight gain, and feed conversion might be adversely affected in broilers as a result of changes in energy metabolism. Therefore, this study was conducted to investigate the influences of acute BA doses on energy metabolism of chick pectoral muscle (PM). Chicks were fed by giving the aqueous solutions supplemented with BA (0, 0.27, 0.54, 1.08, 1.35, 2.25, 3.375 and 4.5 mmol B/kg b.wt.). Breast muscle samples were taken at 24, 48 and 72 h and analyzed histochemically, ultrastructurally and biochemically. Data collected in these analyses indicated that consumption of diets containing up to 2.25 mmol B/kg at 24, 48 and 72h was not detrimental to broiler PM. However, 3.375 mmol B/kg b.wt. (at 24 h) and 4.5 mmol B/kg b.wt.(at 24 and 48 h) caused decreased metabolite concentrations (glucose, glycogen, lactate and ATP) in muscle fibers (Type IIB). Subsarcolemmal (SS) mitochondria and intermyofibrillar (IM) mitochondrial damage (cristae dissolution) were also observed by toxic effect of BA (4.5 mmol B/kg b.wt.). These observations proved that BA at the high doses (3.375 and 4.5 mmol B/kg b.wt.) causes to altered energy metabolism in Type IIB as dependent on time. Based on these results we think that energy protection in muscle against BA toxicity will be the most important study subject. Thus, high BA doses will not have detrimental effects on broiler performance.

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Effect of impaired glucose uptake on postexercise glycogen repletion in skeletal muscles of insulin-treated streptozotocin-diabetic fasted rats

Cited by 6 publications

References 33 publications

Fiber-specific responses of muscle glycogen repletion in fasted rats physically active during recovery from high-intensity physical exertion

Fiber-specific responses of muscle glycogen repletion in fasted rats physically active during recovery from high-intensity physical exertion

Regional variations in intramyocellular lipid concentration correlate with muscle fiber type distribution in rat tibialis anterior muscle

Acute toxicity of boric acid on energy metabolism of the breast muscle in broiler chickens

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