Navegando por Palavras-chave "Leucine"
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- ItemSomente MetadadadosCharacterization and role of the 3-methylglutaconyl coenzyme A hidratase in Trypanosoma brucei(Elsevier Science Bv, 2017) De Lima-Stein, Mariana Leão [UNIFESP]; Icimoto, Marcelo Yudi [UNIFESP]; Levatti, Erica Valadares de Castro [UNIFESP]; Oliveira, Vitor [UNIFESP]; Straus, Anita Hilda [UNIFESP]; Schenkman, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Trypanosoma brucei, the agent of African Trypanosomiasis, is a flagellated protozoan parasite that develops in tsetse flies and in the blood of various mammals. The parasite acquires nutrients such as sugars, lipids and amino acids from their hosts. Amino acids are used to generate energy and for protein and lipid synthesis. However, it is still unknown how T. brucei catabolizes most of the acquired amino acids. Here we explored the role of an enzyme of the leucine catabolism, the 3-methylglutaconyl-Coenzyme A hydratase (3-MGCoA-H). It catalyzes the hydration of 3-methylglutaconyl-Coenzyme A (3-MGCoA) into 3-hydroxymethylglutaryl-Coenzyme A (3-HMGCoA). We found that 3-MGCoA-H localizes in the mitochondria) matrix and is expressed in both insect and mammalian bloodstream forms of the parasite. The depletion of 3-MGCoA-H by RNA interference affected minimally the proliferation of both forms. However, an excess of leucine in the culture medium caused growth defects in cells depleted of 3-MGCoA-H, which could be reestablished by mevalonate, a precursor of isoprenoids and steroids. Indeed, procyclics depleted of the 3-MGCoA-H presented reduced levels of synthesized steroids relative to cholesterol that is scavenged by the parasite, and these levels were also reestablished by mevalonate. These results suggest that accumulation of leucine catabolites could affect the level of mevalonate and consequently inhibit the sterol biosynthesis, required for T. brucei growth. (C) 2017 Elsevier B.V. All rights reserved.
- ItemAcesso aberto (Open Access)Efeito da leucina na hipertrofia cardíaca e na concentração sérica de creatina quinase em ratos Wistar em hipertireoidismo experimental(Univ Federal Uberlandia, 2013-03-01) Fidale, Thiago Montes; Goncalves, Alexandre; Paranhos Lopes, Leandro Teixeira; Alves, Poliana Rodrigues; Souza, Fernanda Rodrigues de; Dias Nunes, Joao Elias; Mundim, Antonio Vicente; Resende, Elmiro Santos [UNIFESP]; Universidade Federal de Uberlândia (UFU); Universidade de Brasília (UnB); Universidade Federal de São Paulo (UNIFESP)Leucine is a regulator of protein metabolism in vivo, and there is little information regarding its action on cardiac hypertrophy induced by experimental hyperthyroidism and its relationship to serum creatine kinase. The study aimed to verify the effect of leucine in cardiac hypertrophy and serum creatine kinase in rats with hyperthyroidism. We used 20 animals were divided into four groups and these control, hormone, hormone + leucine and leucine. Hyperthyroidism was induced by administration of daily 20 mu g/100 grams of levothyroxine sodium in aqueous suspension by gavage. Leucine was supplemented by adding 5% of the amino conventional diet. Blood was collected by cardiac puncture and analyzes made in kit CK-NAC, CK-MB and TSH. At the end of the trial period of seven days the hearts were removed and weighed. Subsequently, the left ventricle was separated together with the interventricular septum and weighed. In statistical comparison was used analysis of variance (ANOVA) and two-way post-Tukey test, considering p values <0.05. Serum concentrations of serum CK-MB were lower in leucine (p <0.05) and hormone + leucine (p <0.05) compared to control. The hormone group, showed greater relative heart weight than the control group (p <0.05) and absolute heart weight greater than hormone + leucine (p <0.05). In conclusion, leucine appears to reduce cardiac hypertrophy and serum concentration of creatine kinase by unknown mechanisms.
- ItemAcesso aberto (Open Access)Efeitos da Suplementação com Whey Protein e da Prática de Exercícios Físicos no Músculo Esquelético de Idosos: uma Revisão da Literatura(Universidade Federal de São Paulo, 2021-02-26) Rebelo, Rachel Soares Macedo [UNIFESP]; Lambertucci, Rafael Herling [UNIFESP]; http://lattes.cnpq.br/5826005580515987; http://lattes.cnpq.br/7726580702379579; Universidade Federal de São Paulo (UNIFESP)O envelhecimento é capaz de promover diversas mudanças dentro e fora do organismo, especialmente alterações na composição corporal, como a perda de massa magra e a redução da força, processos conhecidos como sarcopenia e dinapenia, respectivamente. A manutenção da saúde nessa etapa da vida pode ser realizada pela adoção de hábitos saudáveis, principalmente com a manipulação da dieta e protocolos de treino individualizados que priorizem o treinamento resistido. O objetivo deste estudo foi apresentar os principais benefícios da suplementação com whey protein e da prática de exercícios físicos no tecido muscular esquelético de idosos, por meio de uma revisão narrativa de literatura, a partir da Biblioteca SciELO e PubMed no período de 2000 a 2020. Os resultados demonstraram que idosos se beneficiam do treinamento de força e da suplementação com whey protein, pois ambos os estímulos são capazes de interagir com a mesma via de sinalização para aumento de força e hipertrofia muscular, por meio do complexo mTOR.
- ItemAcesso aberto (Open Access)Increased Dietary Leucine Reduces Doxorubicin-Associated Cardiac Dysfunction in Rats(Frontiers Media Sa, 2018) Fidale, Thiago Montes; Antunes, Hanna Karen Moreira [UNIFESP]; Santos, Luciano Alex dos; Souza, Fernanda Rodrigues de; Deconte, Simone Ramos; Moura, Francyelle Borges Rosa de; Mantovani, Matheus Matioli; Alves, Poliana Rodrigues; Roever, Leonardo; Resende, Elmiro Santos; Universidade Federal de São Paulo (UNIFESP)Cardiotoxicity is one of the most significant adverse effects of the oncologic treatment with doxorubicin, which is responsible for a substantial morbid and mortality. The occurrence of heart failure with ventricular dysfunction may lead to severe cardiomyopathy and ultimately to death. Studies have focused on the effects of leucine supplementation as a strategy to minimize or revert the clinical condition of induced proteolysis by several clinical onsets. However, the impact of leucine supplementation in heart failure induced by doxorubicin is unknown. Therefore, the objective of this work is to evaluate the effects of leucine supplementation on the cardiotoxicity in the heart of rats treated with doxorubicin. Rats treated with a 7.5 mg/kg cumulative dose of doxorubicin for 14 days presented a dilatation of the left ventricle (LV), and a reduction of the ejection fraction (FE). The 5% supplementation of leucine in the rats' food prevented the malfunctioning of the LV when administered with doxorubicin. Some alterations in the extracellular matrix remodeling were confirmed by the increase of collagen fibers in the doxorubicin group, which did not increase when the treatment was associated with leucine supplementation. Leucine attenuates heart failure in this experimental model with doxorubicin. Such protection is followed by the maintenance of interstitial collagen fibers.
- ItemSomente MetadadadosMechanisms of insulin secretion in malnutrition: modulation by amino acids in rodent models(Springer, 2011-04-01) Oliveira, Camila Aparecida Machado de [UNIFESP]; Latorraca, Marcia Queiroz; Rostom de Mello, Maria Alice; Carneiro, Everardo Magalhaes; Universidade Estadual de Campinas (UNICAMP); Univ Fed Mato Grosso UFMT; Univ Estadual Paulista UNESP; Universidade Federal de São Paulo (UNIFESP)Protein restriction at early stages of life reduces beta-cell volume, number of insulin-containing granules, insulin content and release by pancreatic islets in response to glucose and other secretagogues, abnormalities similar to those seen in type 2 diabetes. Amino acids are capable to directly modulate insulin secretion and/or contribute to the maintenance of beta-cell function, resulting in an improvement of insulin release. Animal models of protein malnutrition have provided important insights into the adaptive mechanisms involved in insulin secretion in malnutrition. in this review, we discuss studies focusing on the modulation of insulin secretion by amino acids, specially leucine and taurine, in rodent models of protein malnutrition. Leucine supplementation increases insulin secretion by pancreatic islets in malnourished mice. This effect is at least in part due to increase in the expression of proteins involved in the secretion process, and the activation of the PI3K/PKB/mTOR pathway seems also to contribute. Mice supplemented with taurine have increased insulin content and secretion as well as increased expression of genes essential for beta-cell functionality. the knowledge of the mechanisms through which amino acids act on pancreatic beta-cells to stimulate insulin secretion is of interest for clinical medicine. It can reveal new targets for the development of drugs toward the treatment of endocrine diseases, in special type 2 diabetes.
- ItemAcesso aberto (Open Access)Suplementação de leucina e quercetina, possível papel metabólico em modelo de obesidade induzido por dieta hiperlipídica e hiperglicídica(Universidade Federal de São Paulo (UNIFESP), 2017-05-30) Moreno, Mayara Franzoi [UNIFESP]; Oyama, Lila Missae [UNIFESP]; http://lattes.cnpq.br/7125541171554727; http://lattes.cnpq.br/9090893466948711; Universidade Federal de São Paulo (UNIFESP)Objetivo: Avaliar as alterações fisiológicas e bioquímicas decorrentes da administração de leucina e/ou quercetina em um modelo animal de obesidade induzida por dieta hiperlipídica-hiperglicídica em camundongos. Métodos: Foram utilizados camundongos machos C57BL/6J divididos em cinco grupos experimentais: controle (C); hiperlipídicahiperglicídica (H); H+leucina (HL); H+quercetina (HQ); H+leucina+quercetina (HLQ). Foram analisados: massa corporal, massas dos tecidos adiposos e gastrocnêmio, monitoramento da homeostase da glicose (teste de tolerância à insulina e teste tolerância oral de a glicose), biomarcadores metabólicos (colesterol total, triacilgliceróis, lipopolisacarideos), biomarcadores inflamatórios (TNF-α, IL-10, IL-6 e adiponectina), biomarcadores relacionados a atividade antioxidante (superóxido dismutase, catalase e glutationa peroxidase), conteúdo energético das fezes, análise dos ácidos graxos de cadeia curta fecais, 8-isoprostano livre no plasma, expressão gênica por qPCR no colon (Occludin, Muc2, Fiaf). Resultados: De forma isolada ou sinérgica a quercetina e a leucina não melhoraram o ganho de massa corporal, adiposidade, homeostase da glicose ou a sensibilidade à insulina em camundongos alimentados com dieta H. Entretanto, nossos dados sugerem que a quercetina e/ou leucina poderiam atuar favoravelmente na redução do estresse oxidativo ao prevenir o aumento espécies reativas de oxigênio induzido pela dieta H, (modulando as enzimas antioxidantes como CAT e GPx; e as frações livres de 8-Isoprostano), interferindo positivamente na progressão da obesidade com consequências benéficas preliminares aos distúrbios metabólicos associados à obesidade. Além disso, a coadministração de quercetina e leucina aumentou significativamente a expressão do mRNA do fator adiposo induzido pelo jejum (Fiaf) e da Muc2. Conclusão: O presente estudo indica que a quercetina e leucina exercem efeitos isolados e sinérgicos metabolicamente benéficos e que esses efeitos estão associados a mudanças na atividade antioxidante e fisiologia intestinal. Além disso, mais pesquisas são necessárias para avaliar a aplicabilidade terapêutica da quercetina e leucina no tratamento da obesidade.