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Several studies have demonstrated that a maternal low-protein diet induces long-term metabolic disorders, but the involved mechanisms are unclear. This study investigated the molecular effects of a low-protein diet during pregnancy and lactation on glucose and protein metabolism in soleus muscle isolated from adult male rats. Female rats were fed either a normal protein diet or low-protein diet during gestation and lactation. After weaning, all pups were fed a normal protein diet until the 210th day postpartum. In the 7th month of life, mass, contractile function, protein and glucose metabolism, and the Akt-mTOR pathway were measured in the soleus muscles of male pups. Dry weight and contractile function of soleus muscle in the low-protein diet group rats were found to be lower compared to the control group. Lipid synthesis was evaluated by measuring palmitate incorporation in white adipose tissue. Palmitate incorporation was higher in the white adipose tissue of the low-protein diet group. When incubated soleus muscles were stimulated with insulin, protein synthesis, total amino acid incorporation and free amino acid content, glucose incorporation and uptake, and glycogen synthesis were found to be reduced in low-protein diet group rats. Fasting glycemia was higher in the low-protein diet group. These metabolic changes were associated with a decrease in Akt and GSK-3ß signaling responses to insulin and a reduction in RPS6 in the absence of the hormone. There was also notably lower expression of Akt in the isolated soleus muscle of low-protein diet group rats. This study is the first to demonstrate how maternal diet restriction can reduce skeletal muscle protein and mass by downregulating the Akt-mTOR pathway in adulthood.
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Predictions about global warming have raised interest in assessing whether ectothermic organisms will be able to adapt to these changes. Understanding the physiological mechanisms and metabolic adjustment capacity of fish subjected to heat stress can provide subsidies that may contribute to decision-making in relation to ecosystems and organisms subjected to global climate change. This study investigated the antioxidant defence system and energy metabolism of carbohydrate and protein responses in the gill, liver and kidney tissues of Psalidodon bifasciatus (Garavello & Sampaio 2010), a Brazilian freshwater fish used in aquaculture and in biological studies, following exposure to heat shock at 31°C for 2, 6, 12, 24 and 48 h. The fish presented signs of stress in all tissues tested, as evidenced by increased lipid peroxidation concentration at 2 h and phosphofructokinase, hexokinase and malate dehydrogenase activity at 48 h in the gills; increased glutathione-S-transferase activity at 12 h, citrate synthase activity at 24 h and concentration of reduced glutathione (GSH) concentration at 12 and 48 h in the liver; and through increased activity of superoxide dismutase at 48 h, glutathione reductase at 24 h, glucose-6-phosphate dehydrogenase at 48 h and concentration of GSH at 24 h in the kidney. In the kidneys, changes in the antioxidant system were more prominent, whereas in the gills, there were greater changes in the carbohydrate metabolism. These results indicated the importance of glycolysis and aerobic metabolism in the gills, aerobic metabolism in the liver and pentose-phosphate pathway in the kidneys during homeostasis. The biomarker response was tissue specific, with the greatest number of biomarkers altered in the gills, followed by those in the kidneys and liver.
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Antioxidantes , Characidae , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Characidae/metabolismo , Ecossistema , Metabolismo Energético , Brânquias/metabolismo , Glutationa/metabolismo , Glutationa/farmacologia , Glutationa Peroxidase/metabolismo , Glutationa Peroxidase/farmacologia , Resposta ao Choque Térmico , Peroxidação de Lipídeos , Fígado/metabolismo , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Superóxido Dismutase/farmacologiaRESUMO
This observational study aimed to evaluate serum and urinary amino acid (AA) concentrations in healthy dogs and dogs with chronic kidney disease (CKD) fed a commercial therapeutic renal diet with reduced protein and phosphorus levels. Ten dogs with CKD stages 3 or 4 composed the study group and received the renal diet for 180 days (RG T180). A control group (CG T30) composed of seven healthy dogs was fed a renal diet for 30 days. When comparing serum AA between RG T180 and CG T30, histidine, isoleucine, leucine, lysine, phenylalanine, tryptophan, cysteine, citrulline, ornithine, taurine, branched-chain amino acids (BCAA), and total essential amino acids (EAA) were higher in RG T180. Meanwhile, arginine, asparagine, aspartate, glutamine, serine, and tyrosine were higher in CG T30. Serum phenylalanine, tryptophan, and hydroxyproline were higher in RG T0 (dogs with CKD before consuming a renal diet) when compared to RG T180. In addition, the serum ratios of arginine/citrulline, tyrosine/phenylalanine, and serine/glycine were higher in CG T30 than in RG T180. Concerning urinary AA concentrations in CKD dogs, isoleucine, phenylalanine, tryptophan, aspartate, cysteine, and BCAA were higher in RG T180. In urine, the total EAA/total non-essential AA ratio in RG T180 was higher than in CG T30 as well as tyrosine/phenylalanine ratio higher in CG T30. In conclusion, the combination of renal diet and conservative treatment over 6 months in dogs with CKD stages 3 or 4 affected the AAs metabolism when compared to healthy adult dogs.
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Manganese (Mn) is an important element; yet acute and/or chronic exposure to this metal has been linked to neurotoxicity and neurodegenerative illnesses such as Parkinson's disease and others via an unknown mechanism. To better understand it, we exposed a human neuroblastoma cell model (SH-SY5Y) to two Mn chemical species, MnCl2 and Citrate of Mn(II) (0-2000 µM), followed by a cell viability assay, transcriptomics, and bioinformatics. Even though these cells have been chemically and genetically modified, which may limit the significance of our findings, we discovered that by using RA-differentiated cells instead of undifferentiated SH-SY5Y cell line, both chemical species induce a similar toxicity, potentially governed by disruption of protein metabolism, with some differences. The MnCl2 altered amino acid metabolism, which affects RNA metabolism and protein synthesis. Citrate of Mn(II), however, inhibited the E3 ubiquitin ligases-target protein degradation pathway, which can lead to the buildup of damaged/unfolded proteins, consistent with histone modification. Finally, we discovered that Mn(II)-induced cytotoxicity in RA-SH-SY5Y cells shared 84 percent of the pathways involved in neurodegenerative diseases.
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Calcitonin Gene-Related Peptide (CGRP) is a potent vasodilator peptide widely distributed in the central nervous system and various peripheral tissues, including cardiac muscle. However, its role in heart protein metabolism remains unknown. We examined the acute effects of CGRP on autophagy and the related signaling pathways in the heart mice and cultured neonatal cardiomyocytes. CGRP (100 µg kg-1; s.c.) or 0.9 % saline was injected in awake male C57B16 mice, and the metabolic profile was determined up to 60 min. In fed mice, CGRP drastically increased glycemia and reduced insulinemia, an effect that was accompanied by reduced cardiac phosphorylation levels of Akt at Ser473 without affecting FoxO. Despite these catabolic effects, CGRP acutely inhibited autophagy as estimated by the decrease in LC3II:LC3I and autophagic flux. In addition, the fasting-induced autophagic flux in mice hearts was entirely abrogated by one single injection of CGRP. In parallel, CGRP stimulated PKA/CREB and mTORC1 signaling and increased the phosphorylation of Unc51-like kinase-1 (ULK1), an essential protein in autophagy initiation. Similar effects were observed in cardiomyocytes, in which CGRP also inhibited autophagic flux and stimulated Akt and FoxO phosphorylation. These ï¬ndings suggest that CGRP in vivo acutely suppresses autophagy in the heart of fed and fasted mice, most likely through the activation of PKA/mTORC1 signaling but independent of Akt.
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Autofagia/efeitos dos fármacos , Peptídeo Relacionado com Gene de Calcitonina/fisiologia , Coração/efeitos dos fármacos , Animais , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Camundongos , Miócitos Cardíacos/efeitos dos fármacos , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacosRESUMO
Although we have shown that catecholamines suppress the activity of the Ubiquitin-Proteasome System (UPS) and atrophy-related genes expression through a cAMP-dependent manner in skeletal muscle from rodents, the underlying mechanisms remain unclear. Here, we report that a single injection of norepinephrine (NE; 1 mg kg-1 ; s.c) attenuated the fasting-induced up-regulation of FoxO-target genes in tibialis anterior (TA) muscles by the stimulation of PKA/CREB and Akt/FoxO1 signaling pathways. In addition, muscle-specific activation of PKA by the overexpression of PKA catalytic subunit (PKAcat) suppressed FoxO reporter activity induced by (1) a wild-type; (2) a non-phosphorylatable; (3) a non-phosphorylatable and non-acetylatable forms of FoxO1 and FoxO3; (4) downregulation of FoxO protein content, and probably by (5) PGC-1α up-regulation. Consistently, the overexpression of the PKAcat inhibitor (PKI) up-regulated FoxO activity and the content of Atrogin-1 and MuRF1, as well as induced muscle fiber atrophy, the latter effect being prevented by the overexpression of a dominant negative (d. n.) form of FoxO (d.n.FoxO). The sustained overexpression of PKAcat induced fiber-type transition toward a smaller, slower, and more oxidative phenotype and improved muscle resistance to fatigue. Taken together, our data provide the first evidence that endogenous PKA activity is required to restrain the basal activity of FoxO and physiologically important to maintain skeletal muscle mass.
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Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteína Forkhead Box O1/metabolismo , Músculo Esquelético/enzimologia , Atrofia Muscular/metabolismo , Animais , Linhagem Celular , Proteína Forkhead Box O3/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/patologia , Mioblastos Esqueléticos/enzimologia , Transdução de SinaisRESUMO
The sympathetic nervous system (SNS) activates cAMP signaling and promotes trophic effects on brown adipose tissue (BAT) through poorly understood mechanisms. Because norepinephrine has been found to induce antiproteolytic effects on muscle and heart, we hypothesized that the SNS could inhibit autophagy in interscapular BAT (IBAT). Here, we describe that selective sympathetic denervation of rat IBAT kept at 25°C induced atrophy, and in parallel dephosphorylated forkhead box class O (FoxO), and increased cathepsin activity, autophagic flux, autophagosome formation, and expression of autophagy-related genes. Conversely, cold stimulus (4°C) for up to 72 h induced thermogenesis and IBAT hypertrophy, an anabolic effect that was associated with inhibition of cathepsin activity, autophagic flux, and autophagosome formation. These effects were abrogated by sympathetic denervation, which also upregulated Gabarapl1 mRNA. In addition, the cold-driven sympathetic activation stimulated the mechanistic target of rapamycin (mTOR) pathway, leading to the enhancement of protein synthesis, evaluated in vivo by puromycin incorporation, and to the inhibitory phosphorylation of Unc51-like kinase-1, a key protein in the initiation of autophagy. This coincided with a higher content of exchange protein-1 directly activated by cAMP (Epac1), a cAMP effector, and phosphorylation of Akt at Thr308, all these effects being abolished by denervation. Systemic treatment with norepinephrine for 72 h mimicked most of the cold effects on IBAT. These data suggest that the noradrenergic sympathetic inputs to IBAT restrain basal autophagy via suppression of FoxO and, in the setting of cold, stimulate protein synthesis via the Epac/Akt/mTOR-dependent pathway and suppress the autophagosome formation, probably through posttranscriptional mechanisms.NEW & NOTEWORTHY The underlying mechanisms related to the anabolic role of sympathetic innervation on brown adipose tissue (BAT) are unclear. We show that sympathetic denervation activates autophagic-lysosomal degradation, leading to a loss of mitochondrial proteins and BAT atrophy. Conversely, cold-driven sympathetic activation suppresses autophagy and stimulates protein synthesis, leading to BAT hypertrophy. Given its high-potential capacity for heat production, understanding the mechanisms that contribute to BAT mass is important to optimize chances of survival for endotherms in cold ambients.
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Tecido Adiposo Marrom , Termogênese , Animais , Autofagia , Temperatura Baixa , Lisossomos , Ratos , Sistema Nervoso SimpáticoRESUMO
Background: The most abundant free amino acid in mammals is glutamine (GLN). Little research has focused on GLNsupplementation for horses, but GLN levels in this species are known to decline after exercise and during lactation. Underphysiological conditions, the body produces Gln in sufficient quantities for general metabolism, and a small part of thisamino acid comes from dietary protein. Little research has so far focused on equine dietary supplementation with freeglutamine or combined with other amino acids during catabolic states or in highly stressful situations. This research wasconducted to evaluate the effects of equine dietary supplementation using a combination of glutamine and glutamate.Materials, Methods & Results: The study involved four Arabian mares, not in training (~380 kg; ~12 years old) and fourtreatments (control, and inclusions of 1, 2 and 4% of GLN+GLU) in a Latin square model. A 7-day washout period wasestablished between each phase. Fifty percent of the mares maintenance energy requirements came from concentrate and50% from hay and grazing. The other 50% came from Tifton hay (Cynodon dactylon), which was supplied ad libitum.After 7 weeks of nutritional supplementation (once a day, in the morning). In the experimental model, the mares weredistributed in a Latin square design comprised of four treatments: control (without inclusion) and inclusions of 1%, 2%and 4% of supplement (AminoGut®, Ajinomoto do Brazil), and four animals. Blood was collected in five stages (fasting,and 60, 120, 240 and 360 min after feeding) in each treatment. The blood samples were analyzed to determine GLN, GLU,urea, creatinine, uric acid, total plasma protein, hematocrit and glucose levels. Glutamine and Glutamate concentrationswere analyzed using the enzymatic spectrophotometric method. The results were analyzed statistically using one- andtwo-way ANOVA and Tukeys test with P set at 5%...(AU)
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Animais , Glutamina , Ácido Glutâmico , Suplementos Nutricionais , Cavalos/sangue , Metabolismo , BiomarcadoresRESUMO
BACKGROUND: Stimulation of ß2 -adrenoceptors can promote muscle hypertrophy and fibre type shift, and it can counteract atrophy and weakness. The underlying mechanisms remain elusive. METHODS: Fed wild type (WT), 2-day fasted WT, muscle-specific insulin (INS) receptor (IR) knockout (M-IR-/- ), and MKR mice were studied with regard to acute effects of the ß2 -agonist formoterol (FOR) on protein metabolism and signalling events. MKR mice express a dominant negative IGF1 receptor, which blocks both INS/IGF1 signalling. All received one injection of FOR (300 µg kg-1 subcutaneously) or saline. Skeletal muscles and serum samples were analysed from 30 to 240 min. For the study of chronic effects of FOR on muscle plasticity and function as well as intracellular signalling pathways, fed WT and MKR mice were treated with formoterol (300 µg kg-1 day-1 ) for 30 days. RESULTS: In fed and fasted mice, one injection of FOR inhibited autophagosome formation (LC3-II content, 65%, P ≤ 0.05) that was paralleled by an increase in serum INS levels (4-fold to 25-fold, P ≤ 0.05) and the phosphorylation of Akt (4.4-fold to 6.5-fold, P ≤ 0.05) and ERK1/2 (50% to two-fold, P ≤ 0.05). This led to the suppression (40-70%, P ≤ 0.05) of the master regulators of atrophy, FoxOs, and the mRNA levels of their target genes. FOR enhanced (41%, P ≤ 0.05) protein synthesis only in fed condition and stimulated (4.4-fold to 35-fold, P ≤ 0.05) the prosynthetic Akt/mTOR/p70S6K pathway in both fed and fasted states. FOR effects on Akt signalling during fasting were blunted in both M-IR-/- and MKR mice. Inhibition of proteolysis markers by FOR was prevented only in MKR mice. Blockade of PI3K/Akt axis and mTORC1, but not ERK1/2, in fasted mice also suppressed the acute FOR effects on proteolysis and autophagy. Chronic stimulation of ß2 -adrenoceptors in fed WT mice increased body (11%, P ≤ 0.05) and muscle (15%, P ≤ 0.05) growth and downregulated atrophy-related genes (30-40%, P ≤ 0.05), but these effects were abolished in MKR mice. Increases in muscle force caused by FOR (WT, 24%, P ≤ 0.05) were only partially impaired in MKR mice (12%, P ≤ 0.05), and FOR-induced slow-to-fast fibre type shift was not blocked at all in these animals. In MKR mice, FOR also restored the lower levels of muscle SDH activity to basal WT values and caused a marked reduction (57%, P ≤ 0.05) in the number of centrally nucleated fibers. CONCLUSIONS: NS/IGF1 signalling is necessary for the anti-proteolytic and hypertrophic effects of in vivo ß2 -adrenergic stimulation and appears to mediate FOR-induced enhancement of protein synthesis. INS/IGF1 signalling only partially contributes to gain in strength and does not mediate fibre type transition induced by FOR.
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Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Fator de Crescimento Insulin-Like I/metabolismo , Insulina/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Proteostase/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Autofagia/efeitos dos fármacos , Lisossomos/metabolismo , Masculino , Camundongos , Camundongos Knockout , Proteínas Musculares/metabolismo , Força Muscular , Músculo Esquelético/fisiopatologia , Fosfatidilinositol 3-Quinases , Proteólise , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
The aim of this study was to evaluate transcriptome changes in the muscle tissue of Bos taurus indicus cull cows subjected to recovery weight gain under grazing conditions. In all, 38 Nellore cull cows were divided randomly into two different management groups: (1) Maintenance (MA) and (2) Recovery gain (RG) from weight loss by moderate growth under high forage availability. After slaughter, RNA analysis was performed on the Longissimus thoracis muscle. Semaphorin 4A, solute carrier family 11 member 1, and Ficolin-2 were expressed in the RG, which may indicate an inflammatory response during tissue regrowth. Signaling factors, such as Myostatin, related to fibroblast activation, negative control of satellite cell proliferation in adults and muscle protein synthesis were less abundant in the RG group. The only gene related to anabolic processes that were more abundant in the MA group was related to fat deposition. The genes that were differentially expressed in the experiment showed muscle repair-related changes during RG based on the greater expression of genes involved in inflammatory responses and the lower expression of negative regulators of muscle cell proliferation and hypertrophy.
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Bovinos/genética , Matriz Extracelular/genética , Expressão Gênica , Músculo Esquelético/metabolismo , Transcriptoma/fisiologia , Aumento de Peso , Animais , Bovinos/fisiologia , Dieta , Feminino , Distribuição AleatóriaRESUMO
Background: The most abundant free amino acid in mammals is glutamine (GLN). Little research has focused on GLNsupplementation for horses, but GLN levels in this species are known to decline after exercise and during lactation. Underphysiological conditions, the body produces Gln in sufficient quantities for general metabolism, and a small part of thisamino acid comes from dietary protein. Little research has so far focused on equine dietary supplementation with freeglutamine or combined with other amino acids during catabolic states or in highly stressful situations. This research wasconducted to evaluate the effects of equine dietary supplementation using a combination of glutamine and glutamate.Materials, Methods & Results: The study involved four Arabian mares, not in training (~380 kg; ~12 years old) and fourtreatments (control, and inclusions of 1, 2 and 4% of GLN+GLU) in a Latin square model. A 7-day washout period wasestablished between each phase. Fifty percent of the mares maintenance energy requirements came from concentrate and50% from hay and grazing. The other 50% came from Tifton hay (Cynodon dactylon), which was supplied ad libitum.After 7 weeks of nutritional supplementation (once a day, in the morning). In the experimental model, the mares weredistributed in a Latin square design comprised of four treatments: control (without inclusion) and inclusions of 1%, 2%and 4% of supplement (AminoGut®, Ajinomoto do Brazil), and four animals. Blood was collected in five stages (fasting,and 60, 120, 240 and 360 min after feeding) in each treatment. The blood samples were analyzed to determine GLN, GLU,urea, creatinine, uric acid, total plasma protein, hematocrit and glucose levels. Glutamine and Glutamate concentrationswere analyzed using the enzymatic spectrophotometric method. The results were analyzed statistically using one- andtwo-way ANOVA and Tukeys test with P set at 5%...
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Animais , Cavalos/sangue , Glutamina , Metabolismo , Suplementos Nutricionais , Ácido Glutâmico , BiomarcadoresRESUMO
Many metabolic syndromes lead to energetic disturbs which ends to an intense catabolic state. The branched-chain amino acid leucine shows very positive effects on muscle protein metabolism. However, it is still not clear how leucine acts improving the protein turnover. This study aimed to evaluate in vitro the effects of leucine supplementation in minimising the signalling pathway of protein degradation when mTOR was inhibited. Our studies were conducted in murine C2C12 myotubes exposed to 2mM leucine or 2mM isoleucine in control situation and compared to the inhibition of mTOR by rapamycin. Then, the expression of proteins related to protein synthesis and degradation signalling pathway was obtained by Western Blot. At this concentration, the leucine was sufficient to maintain the expression of proteins evaluated as in control situation. However, when the cells were exposed to rapamycin (80nM), leucine inhibited the expression of SMAD and FoxO3a, showing that leucine was able to modulate the degradation pathway when protein synthesis is compromised. Furthermore, leucine had no effect in modifying the expression of subunits of ubiquitin-proteasome system, showing that leucine had no direct effect in ubiquitin-proteasome system, but acted leading to the phosphorylation of SMAD and FoxO3, which inhibited the activity of transcriptional of these proteins. No similar results were observed in cells exposed to isoleucine under the same experimental protocol, likely showing that leucine has specific action over another branched-chain amino acids. In conclusion, the present study shows that leucine can modulate degradation pathways even under inhibition of mTOR by rapamycin.
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Leucina/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Proteólise , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Animais , Linhagem Celular , Suplementos Nutricionais , Proteína Forkhead Box O3/metabolismo , Camundongos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Sirolimo/farmacologia , Proteína Smad2/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidoresRESUMO
OBJECTIVES: To examine relationships between dietary intake, growth and body composition patterns in patients with inborn errors of intermediary protein metabolism and to determine a safe protein:energy ratio (P:E ratio) associated with optimal growth outcomes. STUDY DESIGN: Retrospective longitudinal data of growth and dietary intake in patients (n = 75) with isovaleric acidemia (IVA; n = 7), methylmalonic acidemia/propionic acidemia (MMA/PA; n = 14), urea cycle defects (UCD; n = 44), classical maple syrup urine disease (MSUD; n = 10) were collected. Prospective longitudinal data of growth, dietary intake, and body composition from 21 patients: IVA (n = 5), MMA/PA (n = 6), UCD (n = 7), and MSUD (n = 3) were collected at clinic visits. RESULTS: Fifty-two of 75 (66%), 49 of 74 (68%), and 44 of 65 (68%) patients had a z-score of 0 (±1) for lifetime weight, height, and body mass index, respectively. Patients with MMA/PA had the lowest median height and weight z-scores, and MSUD patients had highest median body mass index z-score at all ages. In IVA, MMA/PA, and UCD, total natural protein intake met or exceeded the Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO)/United Nations University (UNU) recommended safe levels. Median percentage fat mass was 17.6% in IVA, 20.7% in MMA/PA, 19.4% in UCD, and 17.8% in MSUD. There was a significant negative correlation between percentage fat mass and total protein intake in IVA, MMA/PA, and UCD (r = -0.737; P = .010). The correlation between the P:E ratio and growth variables in IVA, MMA/PA, and UCD suggest a safe P:E ratio (>1.5 to < 2.9) g protein:100 kcal/day. CONCLUSION: Growth outcomes in inborn errors of intermediary protein metabolism are not always ideal. Most patients with IVA, MMA/PA, and UCD consume sufficient natural protein to meet FAO/WHO/UNU recommendations. A P:E ratio range of (>1.5 to < 2.9)g protein/100 kcal/day correlates with optimal growth outcomes.
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Erros Inatos do Metabolismo dos Aminoácidos/fisiopatologia , Composição Corporal/fisiologia , Ingestão de Energia/fisiologia , Adolescente , Distribuição da Gordura Corporal , Estatura/fisiologia , Índice de Massa Corporal , Peso Corporal/fisiologia , Criança , Pré-Escolar , Proteínas Alimentares/administração & dosagem , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudos RetrospectivosRESUMO
Although it is well known that chronic hypoxia induces muscle wasting, the effects of intermittent hypoxia on skeletal muscle protein metabolism remain unclear. We hypothesized that acute intermittent hypoxia (AIH), a challenge that activates the hypothalamic-pituitary-adrenal axis, would alter muscle protein homeostasis through a glucocorticoid-dependent mechanism. Three-week-old rats were submitted to adrenalectomy (ADX) and exposed to 8 h of AIH (6% O2 for 40 s at 9-min intervals). Animals were euthanized, and the soleus and extensor digitorum longus (EDL) muscles were harvested and incubated in vitro for measurements of protein turnover. AIH increased plasma levels of corticosterone and induced insulin resistance as estimated by the insulin tolerance test and lower rates of muscle glucose oxidation and the HOMA index. In both soleus and EDL muscles, rates of overall proteolysis increased after AIH. This rise was accompanied by an increased proteolytic activities of the ubiquitin(Ub)-proteasome system (UPS) and lysosomal and Ca2+-dependent pathways. Furthermore, AIH increased Ub-protein conjugates and gene expression of atrogin-1 and MuRF-1, two key Ub-protein ligases involved in muscle atrophy. In parallel, AIH increased the mRNA expression of the autophagy-related genes LC3b and GABARAPl1. In vitro rates of protein synthesis in skeletal muscles did not differ between AIH and control rats. ADX completely blocked the insulin resistance in hypoxic rats and the AIH-induced activation of proteolytic pathways and atrogene expression in both soleus and EDL muscles. These results demonstrate that AIH induces insulin resistance in association with activation of the UPS, the autophagic-lysosomal process, and Ca2+-dependent proteolysis through a glucocorticoid-dependent mechanism.NEW & NOTEWORTHY Since hypoxia is a condition in which the body is deprived of adequate oxygen supply and muscle wasting is induced, the present work provides evidence linking hypoxia to proteolysis through a glucocorticoid-dependent mechanism. We show that the activation of proteolytic pathways, atrophy-related genes, and insulin resistance in rats exposed to acute intermittent hypoxia was abolished by surgical removal of adrenal gland. This finding will be helpful for understanding of the muscle wasting in hypoxemic conditions.
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Glucocorticoides/metabolismo , Hipóxia/fisiopatologia , Músculo Esquelético/fisiopatologia , Animais , Cálcio/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipotálamo-Hipofisário/fisiopatologia , Hipóxia/metabolismo , Resistência à Insulina/fisiologia , Lisossomos/metabolismo , Lisossomos/fisiologia , Masculino , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Atrofia Muscular/fisiopatologia , Sistema Hipófise-Suprarrenal/metabolismo , Sistema Hipófise-Suprarrenal/fisiopatologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Complexo de Endopeptidases do Proteassoma/fisiologia , Proteólise , Ratos , Ratos Wistar , Ubiquitina/metabolismoRESUMO
In the present study, the effect of grazing intensity (GI) and feed supplementation in sixty-four crossbred Santa Inês lambs was assessed based on performance, blood stress indicators, and metabolic profiles. The GIs analyzed were VH = very high, H = high, L = low, and VL = very low, and were represented by the residual leaf area index (LAIr). The lambs were divided into two groups, supplemented (SP) and non-supplemented (NSP). The dry matter intake (DMI) and average daily gain (ADG) increased linearly with decreasing GI (P 0.05), and the ADG was higher for the NSP group than the SP group (P 0.05). The plasma cortisol concentration was higher in the NSP group (P 0.05), and it was not affected by GIs (P > 0.05). The neutrophil:lymphocyte (N:L) ratio decreased linearly with GI (P 0.05), and the SP group had a higher N:L ratio (P 0.05). None of the parameters evaluated for protein metabolism were affected by GI (P > 0.05), except albumin, where the SP group had a higher concentration of this metabolite (P 0.05). Regarding energy metabolism indicators, glucose showed a linear increase with a decrease in GI (P 0.05) and was higher in the SP group (P 0.05); however, there was a decreasing linear effect (P 0.05) and the NSP group had higher serum levels (P 0.05) of non-esterified fatty acids (NEFA). The concentration of beta...(AU)
No presente estudo foi avaliado o efeito de intensidades de pastejo (IP) pelo índice de área foliar residual (IAFr). Onde, 0,8; 1,4; 2,0 e 2,6 de IAFr corresponde a MA= muito alto, A= alto, B= baixo e MB= muito baixo com suplemento (SP) ou não suplementado (NSP) no desempenho, indicadores de estresse e perfil metabólico em sessenta e quatro cordeiros mestiços Santa Inês (15,40±2,31 kg peso vivo). O consumo de matéria seca (CMS) e ganho médio diário (GMD), em resposta a IP, apresentaram efeito linear crescente (P 0,05) com a diminuição da IP e o grupo NSP foi superior (P 0,05) ao grupo SP quanto ao CMS. A concentração plasmática de cortisol foi maior no grupo NSP (P 0,05) e não apresentou efeito (P>0,05) entre as IP. A relação Neutrófilo:Linfócito apresentou efeito linear decrescente (P 0,05) com a IP e o grupo SPT apresentou maior (P 0,05) relação Neutrófilo:Linfócito. Nenhum dos parâmetros avaliados referentes ao metabolismo proteico foram afetados (P>0,05) pela IP, exceto a Albumina que apresentou efeito (P 0,05) e o grupo SP apresentou maior concentração desse metabólito. Referente aos indicadores do metabolismo energético, a glicose apresentou efeito linear crescente (P 0,05) com o a diminuição da IP e foi maior no grupo SP (P 0,05), de maneira oposta, houve efeito linear decrescente dos ácidos graxos não esterificados (AGNE) (P 0,05)...(AU)
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Animais , Ovinos , Suplementos Nutricionais , Aumento de PesoRESUMO
Background: Chronic cocaine users develop multiple potentially lethal ischemic vascular complications associated with accelerated atherosclerosis. Aim: To assess biochemical and lipid profiles among cocaine dependent subjects in recent abstinence. Material and Methods: A blood sample to measure blood count, biochemical and lipid profiles was obtained from 78 patients aged 19 to 53 years (78% males) who complied with DSM-IV criteria for cocaine dependency. Laboratory results were compared with a group of normal subjects. Results: All cases had positive urinary cocaine, with a mean consumption lapse of 7.6 years. The frequency of smoking was higher in cases. Dependent males had higher body mass index than controls. Compared to controls, dependent females had significantly higher triglyceride (TG) levels and lower HDL cholesterol. Therefore the relation total/HDL cholesterol was higher (p = 0.0365). Dependent males had higher TG levels than their normal counterparts. Dependent subjects consuming cocaine base-paste had higher TG levels. Total proteins, albumin, urea and blood urea nitrogen were lower in dependent subjects. Among males, serum creatinine was lower and blood urea was positively correlated with the daily amount of cocaine use (p = 0.03). After a month of strict abstinence, lipid profile was repeated in 27 patients and remained unchanged. Conclusions: Chronic cocaine use was associated with higher TG in both genders and lower HDL cholesterol in women when compared with a group of healthy counterparts.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Transtornos Relacionados ao Uso de Cocaína/sangue , Cocaína/efeitos adversos , Lipídeos/sangue , Índice de Massa Corporal , Doenças Cardiovasculares , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos Prospectivos , Fatores Sexuais , Triglicerídeos/sangueRESUMO
In the present study, the effect of grazing intensity (GI) and feed supplementation in sixty-four crossbred Santa Inês lambs was assessed based on performance, blood stress indicators, and metabolic profiles. The GIs analyzed were VH = very high, H = high, L = low, and VL = very low, and were represented by the residual leaf area index (LAIr). The lambs were divided into two groups, supplemented (SP) and non-supplemented (NSP). The dry matter intake (DMI) and average daily gain (ADG) increased linearly with decreasing GI (P 0.05), and the ADG was higher for the NSP group than the SP group (P 0.05). The plasma cortisol concentration was higher in the NSP group (P 0.05), and it was not affected by GIs (P > 0.05). The neutrophil:lymphocyte (N:L) ratio decreased linearly with GI (P 0.05), and the SP group had a higher N:L ratio (P 0.05). None of the parameters evaluated for protein metabolism were affected by GI (P > 0.05), except albumin, where the SP group had a higher concentration of this metabolite (P 0.05). Regarding energy metabolism indicators, glucose showed a linear increase with a decrease in GI (P 0.05) and was higher in the SP group (P 0.05); however, there was a decreasing linear effect (P 0.05) and the NSP group had higher serum levels (P 0.05) of non-esterified fatty acids (NEFA). The concentration of beta...
No presente estudo foi avaliado o efeito de intensidades de pastejo (IP) pelo índice de área foliar residual (IAFr). Onde, 0,8; 1,4; 2,0 e 2,6 de IAFr corresponde a MA= muito alto, A= alto, B= baixo e MB= muito baixo com suplemento (SP) ou não suplementado (NSP) no desempenho, indicadores de estresse e perfil metabólico em sessenta e quatro cordeiros mestiços Santa Inês (15,40±2,31 kg peso vivo). O consumo de matéria seca (CMS) e ganho médio diário (GMD), em resposta a IP, apresentaram efeito linear crescente (P 0,05) com a diminuição da IP e o grupo NSP foi superior (P 0,05) ao grupo SP quanto ao CMS. A concentração plasmática de cortisol foi maior no grupo NSP (P 0,05) e não apresentou efeito (P>0,05) entre as IP. A relação Neutrófilo:Linfócito apresentou efeito linear decrescente (P 0,05) com a IP e o grupo SPT apresentou maior (P 0,05) relação Neutrófilo:Linfócito. Nenhum dos parâmetros avaliados referentes ao metabolismo proteico foram afetados (P>0,05) pela IP, exceto a Albumina que apresentou efeito (P 0,05) e o grupo SP apresentou maior concentração desse metabólito. Referente aos indicadores do metabolismo energético, a glicose apresentou efeito linear crescente (P 0,05) com o a diminuição da IP e foi maior no grupo SP (P 0,05), de maneira oposta, houve efeito linear decrescente dos ácidos graxos não esterificados (AGNE) (P 0,05)...
Assuntos
Animais , Aumento de Peso , Ovinos , Suplementos NutricionaisRESUMO
Seedling establishment in saline conditions is crucial for plant survival and productivity. This study was performed to elucidate the biochemical and physiological mechanisms involved with the recovery and establishment of cashew seedlings subjected to salinity. The changes in the Na+ levels and K/Na ratios, associated with relative water content, indicated that osmotic effects were more important than salt toxicity in the inhibition of seedling growth and cotyledonary protein mobilization. Salinity (50mM NaCl) induced a strong delay in protein breakdown and amino acid accumulation in cotyledons, and this effect was closely related to azocaseinolytic and protease activities. In parallel, proline and free amino acids accumulated in the leaves whereas the protein content decreased. Assays with specific inhibitors indicated that the most important proteases in cotyledons were of serine, cysteine and aspartic types. Proteomic analysis revealed that most of the cashew reserve proteins are 11S globulin-type and that these proteins were similarly degraded under salinity. In the late establishment phase, the salt-treated seedlings displayed an unexpected recovery in terms of leaf growth and N mobilization from cotyledon to leaves. This recovery coordinately involved a great leaf expansion, decreased amino acid content and increased protein synthesis in leaves. This response occurred in parallel with a prominent induction in the cotyledon proteolytic activity. Altogether, these data suggest that a source-sink mechanism involving leaf growth and protein synthesis may have acted as an important sink for reserve mobilization contributing to the seedling establishment under salinity. The amino acids that accumulated in the leaves may have exerted negative feedback to act as a signal for the induction of protease activity in the cotyledon. Overall, these mechanisms employed by cashew seedlings may be part of an adaptive process for the efficient rescue of cotyledonary proteins, as the cashew species originates from an environment with N-poor soil and high salinity.
Assuntos
Anacardium/metabolismo , Globulinas/metabolismo , Peptídeo Hidrolases/metabolismo , Proteômica , Aminoácidos/metabolismo , Anacardium/efeitos dos fármacos , Anacardium/crescimento & desenvolvimento , Transporte Biológico , Cotilédone/efeitos dos fármacos , Cotilédone/crescimento & desenvolvimento , Cotilédone/metabolismo , Pressão Osmótica , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Prolina/metabolismo , Salinidade , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Cloreto de Sódio/farmacologia , Estresse FisiológicoRESUMO
Dietary analysis using δ(15)N values of human remains such as bone and hair is usually based on general principles and limited data sets. Even for modern humans, the direct ascertainment of dietary δ(15)N is difficult and laborious, due to the complexity of metabolism and nitrogen fractionation, differing dietary habits and variation of δ(15)N values of food items. The objective of this study was to summarize contemporary regional experimental and global literature data to ascertain mean representative δ(15)N values for distinct food categories. A comprehensive data set of more than 12,000 analyzed food samples was summarized from the literature. Data originated from studies dealing with (1) authenticity tracing or origin control of food items, and (2) effects of fertilization or nutrition on δ(15)N values of plants or animals. Regional German food δ(15)N values revealed no major differences compared with the mean global values derived from the literature. We found that, in contrast to other food categories, historical faunal remains of pig and poultry are significantly enriched in (15)N compared to modern samples. This difference may be due to modern industrialized breeding practices. In some food categories variations in agricultural and feeding regimens cause significant differences in δ(15)N values that may lead to misinterpretations when only limited information is available.
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Proteínas Alimentares/química , Análise de Alimentos/métodos , Isótopos de Nitrogênio/análise , Antropologia Física , Brasil , Grão Comestível/química , Comportamento Alimentar , Alemanha , Humanos , Japão , Carne/análise , Isótopos de Nitrogênio/química , Estados Unidos , Verduras/químicaRESUMO
Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers (13C-lysine, 15N-glycine, ²H5-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg-1·day-1 compared to 0.8 g·kg-1·day-1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h.