Enzymatic adaptations to suspension hypokinesia in skeletal muscle of young and old rats

Simard, C; Lacaille, Michel; Vallières, Julien

doi:10.1016/0047-6374(85)90104-6

Cited by 27 publications

(20 citation statements)

References 9 publications

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“…The protein consists of an ␣-and a ␤-subunit, and in our study both were downregulated after deconditioning and upregulated after exercise training. This is in line with previous studies that reported decreased HADH activity after hindlimb unloading in a rat model (39), and HADH activation following exercise training programs in both animal and human models (12,31,40). The role of HADH in skeletal muscle insulin signaling remains more elusive.…”

Section: Discussionsupporting

confidence: 81%

Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle

Lammers

Poelkens

Duijnhoven

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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Lammers G, Poelkens F, van Duijnhoven NT, Pardoel EM, Hoenderop JG, Thijssen DH, Hopman MT. Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle. Am J Physiol Endocrinol Metab 303: E1245-E1251, 2012. First published October 9, 2012; doi:10.1152/ajpendo.00356.2012.-Physical deconditioning is associated with the development of chronic diseases, including type 2 diabetes and cardiovascular disease. Exercise training effectively counteracts these developments, but the underlying mechanisms are largely unknown. To gain more insight into these mechanisms, muscular gene expression levels were assessed after physical deconditioning and after exercise training of the lower limbs in humans by use of gene expression microarrays. To exclude systemic effects, we used human models for local physical inactivity (3 wk of unilateral limb suspension) and for local exercise training (6 wk of functional electrical stimulation exercise of the extremely deconditioned legs of individuals with a spinal cord injury). The most interesting subset of genes, those downregulated after deconditioning as well as upregulated after exercise training, contained 18 genes related to both the "insulin action" and "adipocytokine signaling" pathway. Of these genes, the three with strongest up/downregulation were the muscular fatty acid-binding protein-3 (FABP3), the fatty acid oxidizing enzyme hydroxyacyl-CoA dehydrogenase (HADH), and the mitochondrial fatty acid transporter solute carrier 25 family member A20 (SLC25A20). The expression levels of these genes were confirmed using RT-qPCR. The results of the present study indicate an important role for a decreased transport and metabolism of fatty acids, which provides a link between physical activity levels and insulin signaling.transcriptome; microarray; fatty acid metabolism; insulin resistance THE HUMAN GENOME HAS EVOLVED on the basis of a physically active lifestyle, but our society has become increasingly sedentary. Physical inactivity has detrimental health consequences, including the development of insulin resistance and eventually type 2 diabetes and cardiovascular disease (8, 41). Recently, it has been demonstrated that even a 2-wk reduction in daily activity level can be sufficient to increase insulin resistance in healthy subjects, as does 9 days of strict bed rest (1, 26). On the other end of the spectrum, a single bout of exercise can reduce insulin resistance (17), regular physical activity reduces the risk of developing diabetes (21, 29), and significant exercise effects have been reported in diabetics (9), making exercise a powerful tool in the prevention and management of type 2 diabetes.Skeletal muscle accounts for the majority of insulin-induced glucose uptake. Binding of insulin to its receptor on the cellular plasma membrane leads, via the activation of intracellular insulin receptor substrates 1 and 2 (IRS1/2), to translocation of the GLUT4 glucose transporter to the plasma membr...

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Section: Discussionsupporting

confidence: 81%

Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle

Lammers

Poelkens

Duijnhoven

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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“…unloading of the musculature results in mitochondrial fragmentation (loss of tubular mitochondrial networks and appearance of swollen isolated mitochondria), loss of mitochondria, reduced mitochondrial oxygen consumption, and decreased mRNA and protein expression levels of components of the mitochondrial OXPHOS chain (23,26,30,33,39). This is in line with our finding that hindlimb suspension resulted in decreased mRNA and protein levels of several mitochondrial OXPHOS complex subunits.…”

Section: E619 Alternative Nf-b Signaling During Recovery Of Muscle Oxsupporting

confidence: 82%

“…It has been convincingly demonstrated that physical inactivity or mechanical unloading, as frequently observed in clinical settings in response to immobilization or prolonged bed rest, leads to a coordinated downregulation of muscle oxidative phenotype (OXPHEN: muscle cell-intrinsic features determining the capacity for substrate oxidation) (23,26,30,33,39). Remarkably, the response of muscle OXPHEN, and specifically its molecular regulation, to resumed physical activity after a period of prolonged inactivity has been scarcely described.…”

mentioning

confidence: 99%

Activation of alternative NF-κB signaling during recovery of disuse-induced loss of muscle oxidative phenotype

Remels

Pansters

Gosker

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

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“…Glycolytic and oxidative enzyme activity of whole SOL and EDL muscle homogenates decreased except for LDH activity in SOL muscle and SDH activity in EDL muscle following hindlimb suspension. SIMARD et al (1985) reported that glycolytic and oxidative enzyme activity decreased in both SOL and gastrocnemius muscles following a 3-week suspension hypokinesia. They also reported that these changes might reflect a transformation of fast-twitch fibers to slow-twitch fibers.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructural and metabolic profiles on single muscle fibers of different types after hindlimb suspension in rats.

Takekura

Yoshioka

1989

Jpn.J.Physiol

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Abstracts The relationships between ultrastructural and metabolic profiles in different types of single muscle fiber after hindlimb suspension in rats were examined. Glycolytic (lactate dehydrogenase, LDH; phosphofructokinase, PFK) and oxidative (succinate dehydrogenase, SDH; malate dehydrogenase, MDH) enzyme activities in extensor digitorum longus (EDL) and soleus (SOL) muscles were measured. Relative mitochondrial and lipid droplet volumes were also measured in single muscle fiber of different types. Glycolytic enzyme activity in EDL muscle and oxidative enzyme activity in soleus muscle decreased following suspension for 2 weeks. LDH and PFK activities in fast-twitch (FG, fast-twitch glycolytic; FOG, fast-twitch oxidative glycolytic) fibers and oxidative enzymes in FOG and FG fibers decreased following suspension. Relative mitochondrial volume decreased significantly in all types (SO, slow-twitch oxidative; FOG, and FG) of fibers following suspension. The mitochondrial volume in SO fiber of the control group was significantly (p <0.01) higher than that of suspended group; however, SDH and MDH activities were not different between the control and suspended groups. The structural and metabolic changes following hindlimb suspension were influenced by different factors, respectively. Changes in ultrastructural and metabolic profiles in response to the hindlimb suspension differed according to the type of fibers.

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Enzymatic adaptations to suspension hypokinesia in skeletal muscle of young and old rats

Cited by 27 publications

References 9 publications

Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle

Expression of genes involved in fatty acid transport and insulin signaling is altered by physical inactivity and exercise training in human skeletal muscle

Activation of alternative NF-κB signaling during recovery of disuse-induced loss of muscle oxidative phenotype

Ultrastructural and metabolic profiles on single muscle fibers of different types after hindlimb suspension in rats.

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