Molecular Mechanisms Of Glucose Uptake In Skeletal Muscle At Rest And In Response To Exercise

Glucose uptake is an important phenomenon for cell homeostasis and for organism health. Under resting conditions, skeletal muscle is dependent on insulin to promote glucose uptake.Insulin, after binding to its membrane receptor, triggers a cascade of intracellular reactions culminating in activation of the glucose transporter 4, GLUT4, among other outcomes.This transporter migrates to the plasma membrane and assists in glucose internalization.However, under special conditions such as physical exercise, alterations in the levels of intracellular molecules such as ATP and calcium actto regulate GLUT4 translocation and glucose uptake in skeletal muscle, regardless of insulinlevels.Regular physical exercise, due to stimulating pathways related to glucose uptake, is an important non-pharmacological intervention for improving glycemic control in obese and diabetic patients. In this mini-review the main mechanisms involved in glucose uptake in skeletal muscle in response to muscle contraction will be investigated.23especia

Exercise Counterbalances Rho/ROCK2 Signaling Impairment in the Skeletal Muscle and Ameliorates Insulin Sensitivity in Obese Mice

Physical exercise is considered a fundamental strategy in improving insulin sensitivity and glucose uptake in skeletal muscle. However, the molecular mechanisms underlying this regulation, primarily on skeletal muscle glucose uptake, are not fully understood. Recent evidence has shown that Rho-kinase (ROCK) isoforms play a pivotal role in regulating skeletal muscle glucose uptake and systemic glucose homeostasis. The current study evaluated the effect of physical exercise on ROCK2 signaling in skeletal muscle of insulin-resistant obese animals. Physiological (ITT) and molecular analysis (immunoblotting, and RT-qPCR) were performed. The contents of RhoA and ROCK2 protein were decreased in skeletal muscle of obese mice compared to control mice but were restored to normal levels in response to physical exercise. The exercised animals also showed higher phosphorylation of insulin receptor substrate 1 (IRS1 Serine 632/635) and protein kinase B (Akt) in the skeletal muscle. However, phosphatase and tensin homolog (PTEN) and protein-tyrosine phosphatase-1B (PTP-1B), both inhibitory regulators for insulin action, were increased in obesity but decreased after exercise. The impact of ROCK2 action on muscle insulin signaling is further underscored by the fact that impaired IRS1 and Akt phosphorylation caused by palmitate in C2C12 myotubes was entirely restored by ROCK2 overexpression. These results suggest that the exercise-induced upregulation of RhoA-ROCK2 signaling in skeletal muscle is associated with increased systemic insulin sensitivity in obese mice and further implicate that muscle ROCK2 could be a potential target for treating obesity-linked metabolic disorders

Identify of a tilapia pheromone released by dominant males that primes females for reproduction

Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet necessary to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies and females mate preferentially with dominant territorial males which they visit in aggregations or leks

Long-term effects of moderate physical exercise during early childhood on insulin sensitivity in rats during adulthood

It is of great importance to investigate the effects of physical exercise for metabolic health when performed in early life, and what the adulthood response would be. The aim of this study is to analyse the effects of moderate intensity physical exercise protocol during childhood on the adipose tissue and insulin sensitivity of rats during adulthood. Twenty weaned Wistar (28 days old) were divided into control and trained groups. The Control Group was kept sedentary, and the Trained group was submitted to swimming exercise at 80% of the anaerobic threshold (determined by the lactate minimum test) for 1 hour/day, 5 days/week from 28 to 90 days of age. At the end of the experiment, the body weight, adiposity (adipose tissue weight), insulin sensitivity, glycemia, insulinemia, pancreatic insulin, lipogenic activity in mesenteric fat, lipogenic activity and glycogen store in gastrocnemius and glucose uptake by soleus were analyzed. Trained group showed lower body weight gain, fat acumulation, lipid synthesis, glycemia, insulinemia and pancreatic insulin level. Kitt, HOMA-IR, glycogen store in gastrocnemius and glucose uptake by soleus were higher in this group. Therefore, we conclude that the moderate physical exercise performed during childhood can contribute to the reduction of body fat and insulin resistance during adulthood in Wistar rats.É de grande importância a investigação dos efeitos do exercício para a saúde metabólica quando realizado no início da vida, e quais seriam as respostas durante a fase adulta. O objetivo desse estudo é analisar os efeitos do exercício físico de intensidade moderada durante a infância na adiposidade e sensibilidade à insulina de ratos durante a fase adulta. Vinte ratos Wistar desmamados de 28 dias de vida foram divididos em grupos Controle e Treinado. O grupo Controle permaneceu sedentário, enquanto o grupo Treinado realizou exercício de natação a 80% do limiar anaeróbio (determinado pelo teste de lactato mínimo) por 1hora/dia, 5dias/semana do 28º até o 90º dia de vida. No fim do experimento, a massa corporal, adiposidade, sensibilidade à insulina, glicemia, insulinemia, insulina pancreática, atividade lipogênica do tecido adiposo mesentérico, atividade lipogênica e estoques de glicogênio no músculo gastrocnêmio e captação de glicose pelo músculo sóleo foram analizadas. O grupo Treinado apresentou menor ganho de massa corporal, acúmulo de gordura, síntese de lipídios, glicemia, insulinemia e insulina pancreática. Kitt, HOMA-IR, estoques de glicogênio no gastrocnêmio e captação de glicose pelo sóleo foram maiores nesse grupo. Portanto, concluímos que o exercício físico moderado realizado durante a infância pode contribuir para a redução da adiposidade corporal e resistência à insulina durante a fase adulta em ratos Wistar

Patologias das construções em concreto armado: estudo de caso do edifício histórico da escola Politécnica de Pernambuco / Reinforced concrete construction pathologies: case study on the historical building of the Polytechnic School Of Pernambuco

O Casarão Rosa da POLI, com seus 82 anos de idade, possui grande valor histórico para a instituição, tendo em vista ter sido o local no qual a escola de engenharia iniciou as suas atividades no Campus Benfica. O edifício é estruturalmente composto, essencialmente, por alvenaria estrutural, e possui 18,0% da sua área com estruturas de concreto armado, as quais foram incorporadas ao longo do tempo. Foram realizadas inspeções visuais nos elementos em concreto armado do edifício, nos meses de setembro e novembro de 2019, com a finalidade de identificar as manifestações patológicas e, emitir um diagnóstico, bem como propor ações para a recuperação das estruturas de concreto armado do Casarão. Os resultados obtidos permitem compreender que os problemas críticos nas estruturas são pontuais, especialmente nas vigas que compõem a caixa de escadas da fachada sul. Ações de recuperação das estruturas devem ser tomadas de forma breve, sob pena do aumento dos custos para e recuperação estrutural. Um plano de manutenção para as estruturas de concreto armado é sugerido, visando manter o Casarão Rosa com um bom desempenho e uso pleno

Targeted disruption of inducible nitric oxide synthase protects against aging, S-nitrosation, and insulin resistance in muscle of male mice

Accumulating evidence has demonstrated that S-nitrosation of proteins plays a critical role in several human diseases. Here, we explored the role of inducible nitric oxide synthase (iNOS) in the S-nitrosation of proteins involved in the early steps of the insulin-signaling pathway and insulin resistance in the skeletal muscle of aged mice. Aging increased iNOS expression and S-nitrosation of major proteins involved in insulin signaling, thereby reducing insulin sensitivity in skeletal muscle. Conversely, aged iNOS-null mice were protected from S-nitrosation–induced insulin resistance. Moreover, pharmacological treatment with an iNOS inhibitor and acute exercise reduced iNOS-induced S-nitrosation and increased insulin sensitivity in the muscle of aged animals. These findings indicate that the insulin resistance observed in aged mice is mainly mediated through the S-nitrosation of the insulin-signaling pathway

Overtraining is associated with DNA damage in blood and skeletal muscle cells of Swiss mice

Abstract: Background: The alkaline version of the single-cell gel (comet) assay is a useful method for quantifying DNA damage. Although some studies on chronic and acute effects of exercise on DNA damage measured by the comet assay have been performed, it is unknown if an aerobic training protocol with intensity, volume, and load clearly defined will improve performance without leading to peripheral blood cell DNA damage. In addition, the effects of overtraining on DNA damage are unknown. Therefore, this study aimed to examine the effects of aerobic training and overtraining on DNA damage in peripheral blood and skeletal muscle cells in Swiss mice. To examine possible changes in these parameters with oxidative stress, we measured reduced glutathione (GSH) levels in total blood, and GSH levels and lipid peroxidation in muscle samples. Results: Performance evaluations (i.e., incremental load and exhaustive tests) showed significant intra and inter-group differences. The overtrained (OTR) group showed a significant increase in the percentage of DNA in the tail compared with the control (C) and trained (TR) groups. GSH levels were significantly lower in the OTR group than in the C and TR groups. The OTR group had significantly higher lipid peroxidation levels compared with the C and TR groups. Conclusions Aerobic and anaerobic performance parameters can be improved in training at maximal lactate steady state during 8 weeks without leading to DNA damage in peripheral blood and skeletal muscle cells or to oxidative stress in skeletal muscle cells. However, overtraining induced by downhill running training sessions is associated with DNA damage in peripheral blood and skeletal muscle cells, and with oxidative stress in skeletal muscle cells and total blood.The present work received financial support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP - process numbers 2011/02652-0 and 2010/08239-4). We are grateful for the support provided by Mr. Guilherme F. Alves and Luís A. L. Filho

Obras Pioneiras da Cultura Portuguesa: primeiro tratado pedagógico

Obra sob a direção de: José Eduardo Franco e Carlos Fiolhais, e coordenada por: Adelino CardosoConcluída a formação académica, Verney empenhou-se na redação da sua obra emblemática, o Verdadeiro método de estudar, publicada anonimamente em 1746 e, desde logo, envolta em grande controvérsia. Esta obra é, nas palavras do autor, a peça nuclear de um vasto programa de «restabelecimento das artes e das letras em Portugal», que exige a elaboração de novos compêndios e de obras de síntese nos vários domínios do saber, tendo em atenção o recente avanço dos conhecimentos.info:eu-repo/semantics/publishedVersio