Effects of leucine and phenylalanine supplementation during intermittent periods of food restriction and refeeding in adult rats

Donato, José; Pedrosa, Rogério Graça; Araújo, José Anchieta de; Pires, Ivanir Santana de Oliveira; Tirapegui, Júlio

doi:10.1016/j.lfs.2007.04.015

Cited by 21 publications

(31 citation statements)

References 38 publications

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“…A study using Wistar rats submitted to 3 cycles of food restriction and refeeding (1 week of 50% food restriction, followed by 2-weeks on ad libitum diet, per cycle), with or without chronic L-leucine plus L-phenylalanine supplementation, demonstrated a significant increase in lean body mass and body protein content in the supplemented group compared to the rats submitted to the same protocol without supplementation (Donato et al, 2007).…”

Section: Experimental Studiesmentioning

confidence: 99%

Section: Experimental Studiesmentioning

confidence: 99%

“…Moreover, leucine stimulates a second initiation factor-4G (eIF4G) through the mTor-independent pathway. The association of these two factors, eIF4E and eI-F4G, forms a ribossomal complex eIF4F, which regulates translation initiation (Donato et al, 2007;Stipanuk, 2007). Therefore, leucine also stimulates the synthesis of complexes that are responsible for protein translation process and consequently enhances cellular ability for protein synthesis (Kimball et al, 1999;Donato et al, 2007).…”

mentioning

confidence: 99%

“…Studies evidenced that intravenous leucine infusion at high doses (3 to 7 g) resulted in anabolic changes in protein turnover and nitrogen balance (Platell et al, 2000;Matthews, 2005). Additionally, it was observed that leucine stimulates protein synthesis during catabolic conditions induced by acute food restriction or by exhaustive exercise (Donato et al, 2007;Biolo et al, 1997).It was also evidenced that, after overnight fasting or intense exercise, protein synthesis was reduced compared to the rate of protein degradation in muscle. This catabolic period persisted until adequate amounts of protein, specifically leucine, are consumed in order to increase the plasma and intracellular concentrations of this aminoacid (Phillips, 2004).…”

mentioning

confidence: 99%

“…Furthermore, studies comparing diets with different protein concentrations demonstrated significant changes in body composition in groups on a high-protein diet, especially by reducing fat mass and lowering loss of lean body mass. These changes were partially attributed to increased BCAA consumption, particularly leucine (Layman et al, 2003b;Farnsworth et al, 2003;Westerterp-Plantenga et al, 2004).A study using Wistar rats submitted to 3 cycles of food restriction and refeeding (1 week of 50% food restriction, followed by 2-weeks on ad libitum diet, per cycle), with or without chronic L-leucine plus L-phenylalanine supplementation, demonstrated a significant increase in lean body mass and body protein content in the supplemented group compared to the rats submitted to the same protocol without supplementation (Donato et al, 2007).In a study aiming to investigate the possible mechanisms by which leucine stimulates protein synthesis, Anthony et al (2000) evaluated protein synthesis in the skeletal muscle of animals submitted to food restriction for 18 hours, and in animals with free access to food. Supplementation with leucine, carbohydrate or leucine plus carbohydrate was orally administered to these groups.…”

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Protein synthesis regulation by leucine

Vianna

Teodoro

Leal

et al. 2010

Braz. J. Pharm. Sci.

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In vivo and in vitro studies have demonstrated that high protein diets affect both protein synthesis and regulation of several cellular processes. The role of amino acids as substrate for protein synthesis has been established in the literature. However, the mechanism by which these amino acids modulate transcription and regulate the mRNA translation via mTOR-dependent signaling pathway has yet to be fully determined. It has been verified that mTOR is a protein responsible for activating a cascade of biochemical intracellular events which result in the activation of the protein translation process. Of the aminoacids, leucine is the most effective in stimulating protein synthesis and reducing proteolysis. Therefore, it promotes a positive nitrogen balance, possibly by favoring the activation of this protein. This amino acid also directly and indirectly stimulates the synthesis and secretion of insulin, enhancing its anabolic cellular effects. Therefore, this review aimed to identify the role of leucine in protein synthesis modulation and to discuss the metabolic aspects related to this aminoacid. Uniterms:Leucine. Protein synthesis. Transcription Factors. mTOR. Translation Protein.Estudos in vivo e in vitro verificaram que dietas hiperprotéicas influenciam a síntese protéica e regulam vários processos celulares. O papel dos aminoácidos como substrato para a síntese de proteínas já está bem evidenciado na literatura, porém as formas como esses aminoácidos modulam a etapa da transcrição e regulam a tradução do RNAm, pela via de sinalização dependente da mTOR, ainda não estão totalmente esclarecidas. Tem-se verificado que a mTOR é uma proteína responsável por ativar uma cascata de eventos bioquímicos intracelulares que culminam na ativação do processo de tradução protéica. Dentre todos os aminoácidos, a leucina é a mais eficaz em estimular a síntese protéica, reduzir a proteólise e, portanto, favorecer o balanço nitrogenado positivo, possivelmente por favorecer a ativação desta proteína. Além disso, este aminoácido estimula direta e indiretamente a síntese e a secreção de insulina, e, assim, aumenta as propriedades anabólicas celulares. Nesse sentido, a presente revisão tem como objetivo identificar o papel da leucina na modulação da síntese protéica e abordar aspectos metabólicos relacionados a este aminoácido.Unitermos: Leucina. Síntese protéica. Fator de transcrição. mTOR. Tradução de proteínas. INTRODUCTIONProtein synthesis in tissue is rapidly stimulated after nutrient consumption. Insulin and aminoacids stimulate protein anabolism, acting in a posterior step of gene transcription, i.e., on protein translation. However, the mechanism by which the aminoacids stimulate protein translation has yet to be fully determined (Proud, 2002).Some studies have verified that high-protein diets stimulate protein synthesis. Some of the benefits promoted by this diet on body composition can be attributed to high consumption of branched-chain aminoacids (BCAA), which include the aminoacids leucine, valine and isoleucine (Donato...

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Section: Experimental Studiesmentioning

confidence: 99%

Section: Experimental Studiesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Protein synthesis regulation by leucine

Vianna

Teodoro

Leal

et al. 2010

Braz. J. Pharm. Sci.

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Leucine improves protein nutritional status and regulates hepatic lipid metabolism in calorie‐restricted rats

Pedroso

Nishimura

Matos-Neto

et al. 2013

Cell Biochemistry & Function

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Several studies have highlighted the potential of leucine supplementation for the treatment of metabolic diseases including type 2 diabetes and obesity. Caloric restriction is a common approach to improve the health in diabetic and obese subjects. However, very few studies assessed the effects of leucine supplementation in calorie-restricted animals. Rats were subjected to a 30% calorie-restricted diet for 6 weeks to study the effects of leucine supplementation on protein status markers and lipid metabolism. Caloric restriction reduced the body weight. However, increased leucine intake preserved body lean mass and protein mass and improved protein anabolism as indicated by the increased circulating levels of albumin and insulin-like growth factor-1 (IGF-1), and the liver expression of albumin and IGF-1 messenger RNA. Leucine supplementation also increased the circulating levels of interleukin-6 and leptin but did not affect the tumour necrosis factor-α and monocyte chemotactic protein-1 concentrations. Ketone bodies were increased in rats consuming a leucine-rich diet, but we observed no changes in cholesterol or triglycerides concentrations. Caloric restriction reduced the liver expression of peroxisome proliferator activated receptor-α and glucose-6-phosphatase, whereas leucine supplementation increased the liver expression of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) reductase and sterol regulatory element-binding transcription factor 1. A leucine-rich diet during caloric restriction preserved whole body protein mass and improved markers of protein anabolism. In addition, leucine modulated the hepatic lipid metabolism. These results indicate that increased leucine intake may be useful in preventing excessive protein waste in conditions of large weight loss.

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Dietary leucine requirement of juvenile Japanese seabass (Lateolabrax japonicus)

Cheng

Mai

et al. 2015

J. Ocean Univ. China

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A 56-day feeding trial was conducted to examine the dietary leucine requirement of juvenile Japanese seabass in seawater floating net cages (1.5 m × 1.5 m × 2.0 m). Six isonitrogenous (crude protein 40%) and isoenergetic (gross energy 20 kJ g −1 ) diets were formulated to contain different concentrations of leucine (0.9%, 1.49%, 2.07%, 2.70%, 3.30% and 3.88% of dry matter). Crystalline L-amino acids were supplemented to simulate the whole body amino acid pattern of Japanese seabass except for leucine. Three groups (30 fish individuals each, 8.0 g ± 0.20 g in initial weight) were fed to apparent satiation at 5:00 and 17:30 every day. During the experimental period, the water temperature ranged from 26 to 32℃ and salinity from 26 to 30, and the dissolved oxygen was maintained at 7 mg L −1 . The results showed that weight gain (WG), nitrogen retention (NR), feed efficiency (FE) and protein efficiency ratio (PER) were significantly increased when dietary leucine was increased from 0.90% to 2.70% of dry matter, and then declined. WG was the highest when fish were fed D4 containing 2.70% of leucine. No significant differences were observed in body composition among dietary treatments (P > 0.05). Considering the change of WG, the optimum dietary leucine requirement of juvenile Japanese seabass was either 2.39% of dry matter or 5.68% of dietary protein.

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Effects of leucine and phenylalanine supplementation during intermittent periods of food restriction and refeeding in adult rats

Cited by 21 publications

References 38 publications

Protein synthesis regulation by leucine

Protein synthesis regulation by leucine

Leucine improves protein nutritional status and regulates hepatic lipid metabolism in calorie‐restricted rats

Dietary leucine requirement of juvenile Japanese seabass (Lateolabrax japonicus)

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