Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats

Nicastro, Humberto; Zanchi, Nelo Eidy; Luz, Claudia Ribeiro da; Moraes, Wilson Max Almeida Monteiro de; Ramona, Pamella; Filho, Mário Alves de Siqueira; Chaves, Daniela Fojo Seixas; Medeiros, Alessandra; Brum, Patrícia Chakur; Dardevet, Dominique; Lancha, Antônio Herbert

doi:10.1016/j.nut.2011.08.008

Cited by 45 publications

(48 citation statements)

References 48 publications

(55 reference statements)

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“…We also observed that this impaired translocation occurred through decreased phosphorylation of Akt. However, we did not find significant differences in p70S6k phosphorylation, suggesting a possible p70S6k-independent mechanism [35].…”

Section: Direct Effects Of Aa On Insulin Signaling In Skeletal Musclecontrasting

confidence: 69%

The possible role of leucine in modulating glucose homeostasis under distinct catabolic conditions

et al. 2012

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Branched-chain amino acids (BCAA) (especially leucine) have been shown to activate protein synthesis pathways, decrease proteolysis and increase insulin sensitivity. Furthermore, it appears that leucine can be used as a nutritional therapy to avoid sarcopenia and skeletal muscle atrophy due to immobilization or glucocorticoid treatment. However, it is of note that all of these conditions are related to insulin resistance to varying degrees and affect different tissues, particularly skeletal muscle. Additionally, evidence from recent studies demonstrate that a combination of protein containing high levels of leucine with nutrients containing saturated fatty acids or an excess of leucine are capable of inducing insulin resistance. From this discussion, a few major questions arise. First, what is the role of a combination of macronutrients in inducing insulin resistance? Second, in insulin resistance, does leucine supplementation follow the same path observed under healthy conditions? Finally, what are the dose-dependent outcome and the latency of leucine effect under such conditions? The present article discusses these questions based on data from the literature and experiments performed by our group.

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Section: Direct Effects Of Aa On Insulin Signaling In Skeletal Musclecontrasting

confidence: 69%

The possible role of leucine in modulating glucose homeostasis under distinct catabolic conditions

et al. 2012

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“…Leucine supplementation studies that look at skeletal muscle regeneration in the acute phase (2-4 days post-injury), commonly prime the body by administering leucine a few days prior to the induction of injury (Nicastro et al, 2012; Pereira et al, 2014). Pereira et al (2015) studied the effects of leucine supplementation on muscle regeneration in aged rats and show an improved regeneration potential.…”

Section: Introductionmentioning

confidence: 99%

Differential effects of leucine supplementation in young and aged mice at the onset of skeletal muscle regeneration

Perry

Brown

Lee

et al. 2016

Mechanisms of Ageing and Development

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Aging decreases the ability of skeletal muscle to respond to injury. Leucine has been demonstrated to target protein synthetic pathways in skeletal muscle thereby enhancing this response. However, the effect of aging on leucine-induced alterations in protein synthesis at the onset of skeletal muscle regeneration has not been fully elucidated. The purpose of this study was to determine if aging alters skeletal muscle regeneration and leucine-induced alterations in markers of protein synthesis. The tibialis anterior of young (3 months) and aged (24 months) female C57BL/6J mice were injected with either bupivacaine or PBS, and the mice were given ad libitum access to leucine-supplemented or normal drinking water. Protein and gene expression of markers of protein synthesis and degradation, respectively, were analyzed at three days post-injection. Following injury in young mice, leucine supplementation was observed to elevate only p-p70S6K. In aged mice, leucine was shown to elicit higher p-mTOR content with and without injury, and p-4EBP-1 content post-injury. Additionally in aged mice, leucine was shown to elicit higher content of relative p70S6K post-injury. Our study shows that leucine supplementation affects markers of protein synthesis at the onset of skeletal muscle regeneration differentially in young and aged mice.

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“…Branched-chain amino acids (BCAA—leucine, isoleucine and valine) supplementation, especially leucine, has been described as a potential therapeutic tool capable to attenuate skeletal muscle atrophy induced by several catabolic conditions, such as cancer, sepsis, muscular diseases [1] and glucocorticoid treatment [2]. Since leucine is considered as the second more potent insulin secretagogue amongst all the amino acids (AA) [3], it has been studied for its capacity to modulate whole body glucose homeostasis [4].…”

Section: Introductionmentioning

confidence: 99%

Dose and Latency Effects of Leucine Supplementation in Modulating Glucose Homeostasis: Opposite Effects in Healthy and Glucocorticoid-Induced Insulin-Resistance States

et al. 2012

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Dexamethasone (DEXA) is a potent immunosupressant and anti-inflammatory agent whose main side effects are muscle atrophy and insulin resistance in skeletal muscles. In this context, leucine supplementation may represent a way to limit the DEXA side effects. In this study, we have investigated the effects of a low and a high dose of leucine supplementation (via a bolus) on glucose homeostasis, muscle mass and muscle strength in energy-restricted and DEXA-treated rats. Since the leucine response may also be linked to the administration of this amino acid, we performed a second set of experiments with leucine given in bolus (via gavage) versus leucine given via drinking water. Leucine supplementation was found to produce positive effects (e.g., reduced insulin levels) only when administrated in low dosage, both via the bolus or via drinking water. However, under DEXA treatment, leucine administration was found to significantly influence this response, since leucine supplementation via drinking water clearly induced a diabetic state, whereas the same effect was not observed when supplied via the gavage.

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Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats

Abstract: Resistance exercise but not LEU supplementation promoted fiber type transition and improved glucose homeostasis in DEXA-treated rats.

Cited by 45 publications

References 48 publications

The possible role of leucine in modulating glucose homeostasis under distinct catabolic conditions

The possible role of leucine in modulating glucose homeostasis under distinct catabolic conditions

Differential effects of leucine supplementation in young and aged mice at the onset of skeletal muscle regeneration

Dose and Latency Effects of Leucine Supplementation in Modulating Glucose Homeostasis: Opposite Effects in Healthy and Glucocorticoid-Induced Insulin-Resistance States

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