574 resultados para Glycogen


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Estudos têm demonstrado que o exercício físico regular melhora as condições do diabetes, facilitando a captação periférica da glicose e o metabolismo de glicogênio, proteínas, etc. Por outro lado, pouco se conhece sobre os efeitos do exercício intenso em diabéticos, principalmente com relação ao sistema imune desses organismos. O presente estudo teve como objetivo verificar os efeitos de um treinamento físico de alta intensidade sobre a contagem total e diferencial de leucócitos em ratos diabéticos. Ratos machos jovens Wistar foram distribuídos em quatro grupos: controle sedentário (CS), controle treinado (CT), diabético sedentário (DS) e diabético treinado (DT). O diabetes foi induzido por aloxana (35mg/kg de peso corporal). Durante seis semanas os animais dos grupos CT e DT realizaram um protocolo de treinamento físico, que consistiu na realização de quatro séries de 10 saltos (intercaladas por um minuto de intervalo) em piscina, com o nível da água correspondendo a 150% do comprimento corporal e sobrecarga equivalente a 50% da massa corporal dos animais. Ao final do período experimental, amostras de sangue foram coletadas para a contagem total e diferencial dos leucócitos. Os resultados foram avaliados estatisticamente por ANOVA com um nível de significância de 5%. A glicemia foi aumentada entre os diabéticos e a insulinemia diminuída. Não foram observadas diferenças significativas na contagem diferencial dos linfócitos, neutrófilos, eosinófilos e contagem total de leucócitos entre os grupos estudados. Houve aumento dos monócitos entre os treinados (CS = 10,0 ± 4,5, CT* = 25,4 ± 7,9, DS = 19,75 ± 7,4, DT* = 25,8 ± 4,4%). O peso relativo do timo foi reduzido pelo treinamento e pelo diabetes (CS = 125,0 ± 37,7, CT* = 74,6 ± 8,2, DS* = 47,5 ± 12,2, DT* = 40,1 ± 16,9mg/100g). Esses resultados permitem concluir que o treinamento físico de alta intensidade não alterou o estado geral do diabetes, mas aumentou os monócitos, o que pode representar um efeito positivo sobre a resposta imunológica desses animais.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Various types of nuages and lamellae anulata can be found during Dermatobia hominis spermatogenesis. In spermatogonia, the nuages occur as granules juxtaposed to the cytoplasmic face of the nuclear envelope or as cytoplasmic granules similar toglycogen granules. In spermatocytes, in addition to the nuages, dense spherical bodies of approximately 1.0 µm in diameter are also observed. In the spermatids the nuages can be of the following types: perinuclear granules, spherical granules with diameters varying in length from 0.5 to 1.0 µm, granules similar to glycogen granules, granules with variable diameters which accumulate at the flagellum base forming the centriole adjunct, or remain in the cytoplasm. Nuages can also be observed in these cellular types as dense masses, without a definite outline and are common to animal germinal cells in general. The lamellae anulata on the other hand, are observed only in spermatocytes I and in early spermatids, being always immersed in electron-dense material of indefinite outline. In spermatids, the lamellae anulata are close to the nuclear envelope suggesting, in spite of opposing opinions, that these cells are envolved in the synthesis and transport of material from the nucleus to the cytoplasm.

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Cem ratos norvégicus, machos, com aproximadamente 3 meses de idade foram distribuídos por sorteio em 2 grupos experimentais: Grupo Controle (GC): com 50 ratos sadios, não diabéticos e Grupo Diabético (GD): com 50 ratos diabéticos, induzidos pela aloxana, sem qualquer tratamento. Cada grupo foi dividido em 5 subgrupos com 10 ratos cada e sacrificados com 1, 3, 6, 9 e 12 meses de seguimento, respectivamente. Parâmetros clínicos (peso, ingestão hídrica e alimentar, e diurese) e laboratoriais (glicemia, glicose urinária e insulina) foram documentados em todos os momentos de avaliação. Um segmento do nervo ciático foi obtido de cada animal, em ambos os grupos, para estudo à MO. e ME. Alterações clínicas e laboratoriais significativas (P<0,01), compatíveis com diabetes grave, foram observadas em todos os animais do GD a partir do 4o dia após a indução. Ratos de ambos os grupos apresentaram alterações no número de fibras mielínicas e nos depósitos intraaxonais de glicogênio que não diferiram, estatisticamente, aos 1, 3 e 6 meses de seguimento. Entretanto, aos 9 e 12 meses, ratos do GD apresentaram diminuição significativa no número de fibras mielínicas, com aumento do número de fibras mielínicas de menor calibre, quando comparados com ratos do GC (P<0,05). Grânulos de glicogênio intraaxonais também foram mais acentuados em ratos do GD no 9o e 12o mês de seguimento. Não foram observadas diferenças na densidade de fibras amielínicas ou alterações ultraestruturais significativas entre os dois grupos, em relação aos espaços intraaxonais e endoneurais, bainhas de mielina e células de Schwann durante todo o estudo.

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OBJETIVO: Ação do ácido trissódio-cálcio-dietileno-triaminopentaacético (CaNa3DTPA), quelante de ferro com ação ainda anti-viral, antiinflamatória e imunológica, na atenuação de lesões de reperfusão em músculos esqueléticos de ratos. MÉTODOS: 52 ratos Wistar, pesando 188±22g, foram anestesiados e submetidos a semi-amputação de membro posterior direito (MPD), poupando-se o fêmur, artéria e veia femorais. Foram então randomizados e distribuídos: G1-CTAN - controle anestesia, sem cirurgia e sem isquemia; G2-CTCIR - controle cirurgia, sem isquemia; G3-IRCT e G3-IRDTPA - com isquemia (4 hora) e reperfusão ( 2 horas). O G3-IRCT foi tratado, ao final da isquemia, com cloreto de sódio 0,9% e G3-IRDTPA com (CaNa3DTPA).Parâmetros: Circunferência do pé direito e peso do rato, dosagem sérica de CPK, dosagem de malonaldeído e microscopia óptica de músculos soleus bilateral. RESULTADOS: Aumento da circunferência nos G3-IRCT e G3-IRDTPA (significante no G3-IRCT quando comparado ao G1-CTAN); CPK elevado nos G3-IRCT e G3-IRDTPA comparados aos controles; MDA mais alto no membro contralateral do G3-IRDTPA, comparado ao MPD do G3-IRDTPA e ao G1-CTAN; maior edema intersticial em G3-IRCT, maior infiltrado inflamatório em G3-IRDTPA e recuperação dos níveis de glicogênio semelhantes em G3-IRCT e G3-IRDTPA. CONCLUSÃO: Apesar do menor edema no G3-IRDTPA comparado ao G3-IRCT, o CaNa3DTPA não alterou CPK sérico, MDA muscular e morfologia muscular dos animais.

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OBJETIVO: Avaliar os efeitos da suplementação com ácido linoléico conjugado, associada ao treinamento moderado em natação, sobre a composição corporal, o consumo e a eficiência alimentar, a glicemia, o perfil lipídico e o glicogênio muscular e hepático de ratos Wistar. MÉTODOS: Ratos Wistar (30 dias) foram divididos em: sedentário, sedentário suplementado, treinado e treinado suplementado. Permaneceram em gaiolas individuais com comida e água ad libitum, temperatura de 23ºC (com variação de1ºC) e ciclo claro-escuro de 12 horas, durante 8 semanas. A sessão de natação durou 1 hora e foi realizada três vezes/semana, bem como a suplementação com ácido linoléico conjugado a 2%. Após sacrifício, o plasma, os tecidos adiposos brancos e o marrom, o músculo gastrocnêmio e o fígado foram coletados e pesados. RESULTADOS: A suplementação per se não promoveu modificação na ingestão alimentar e na massa corporal dos animais. Houve aumento na glicemia de jejum (p<0,05), nas lipoproteínas de alta densidade (p<0,05), no colesterol total (p<0,05) e redução dos triacilgliceróis. A suplementação associada ao treinamento reduziu a massa corporal (p<0,05) e aumentou o peso relativo do tecido adiposo, do fígado e a glicemia de jejum. CONCLUSÃO: A suplementação com ácido linoléico conjugado associada à prática de exercício físico parece ter influência no balanço energético, mas, por outro lado, o aumento no peso do fígado indica que a ingestão deste ácido graxo pode ter efeitos indesejáveis, aumentando as chances de desenvolvimento do fígado gorduroso. Estes achados apontam perspectivas para novos estudos envolvendo análises histológicas do fígado, expressão gênica de enzimas chaves do metabolismo lipídico e de carboidratos, associados ou não a diferentes protocolos de treinamento físico.

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1. The role of beta(2)-agonist and of cAMP in chick skeletal muscle proteolytic pathways and protein synthesis was investigated using an in vitro preparation that maintains tissue glycogen stores and metabolic activity for several hours.2. In extensor digitorum longus (EDL) muscle total proteolysis decreased by 15 to 20% in the presence of equimolar concentrations of epinephrine, clenbuterol, a selective beta(2)-agonist, or dibutyryl-cAMP. Rates of protein synthesis were not altered by clenbuterol or dibutyryl-cAMP.3. The decrease in the rate of total protein degradation induced by 10(-5) M clenbuterol was paralleled by a 44% reduction in Ca2+-dependent proteolysis, which was prevented by 10(-5) M ICI 118.551, a selective beta(2)-antagonist.4. No change was observed in the activity of the lysosomal, ATP-dependent, and ATP-independent proteolytic systems. Ca2+-dependent proteolytic activity was also reduced by 58% in the presence of 10(-4) M dibutyryl-cAMP or isobutylmethylxanthine.5. The data suggest that catecholamines exert an inhibitory control of Ca2+-dependent proteolysis in chick skeletal muscle, probably mediated by beta(2)-adrenoceptors, with the participation of a cAMP-dependent pathway.

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5-Aminolevulinic acid (ALA), a heme precursor that accumulates in acute intermittent porphyria patients and lead-exposed individuals, has previously been shown to autoxidize with generation of reactive oxygen species and to cause in vitro oxidative damage to rat liver mitochondria. We now demonstrate that chronically ALA-treated rats (40 mg/kg body wt every 2 days for 15 days) exhibit decreased mitochondrial enzymatic activities (superoxide dismutase, citrate synthase) in liver and soleus (type I, red) and gastrocnemius (type IIb, white) muscle fibers. Previous adaptation of rats to endurance exercise, indicated by augmented (cytosolic) CuZn-superoxide dismutase (SOD) and (mitochondrial) Mn-SOD activities in several organs, does not protect the animals against liver and soleus mitochondrial damage promoted by intraperitoneal injections of ALA. This is suggested by loss of citrate synthase and Mn-SOD activities and elevation of serum lactate levels, concomitant to decreased glycogen content in soleus and the red portion of gastrocnemius (type IIa) fibers of both sedentary and swimming-trained ALA-treated rats. In parallel, the type IIb gastrocnemius fibers, which are known to obtain energy mainly by glycolysis, do not undergo these biochemical changes. Consistently, ALA-treated rats under swimming training reach fatigue significantly earlier than the control group. These results indicate that ALA may be an important prooxidant in vivo.

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Aim. To investigate the effects of physical training associated to dexamethasone administration in carbohydrate metabolism and adrenocorticotrophic hormone (ACTH) release. Materials and methods. Young Wistar rats were divided into four groups: sedentary control (CS), sedentary dexanzethasone (DxS), trained control (CT) and trained dexamethasone (DxT). The rats were submitted to swimming training associate to administration of dexamethasone for ten weekends. Before sacrifice the rats received Subcutaneous insulin to calculate the maximum decreased in blood glucose. Venous blood was sampled obtained at the end experiment period to determine glucose, insulin, free fatty acids (FFA) and ACTH. Gastrocnemius and liver tissue samples were used to determination glycogen, and adipose epididimal tissue was used to measured the weight. Results. Dexamethasone administration provoke insulin resistance and the physical training reverted this aspect. Training promoted increase in muscle and liver glycogen store and a high utilization of FFA. Moreover the dexamethasone provoke decreased of ACTH release in response to acute exercise, showing marked differences in the functioning of the hypothalamy pituitary-adrenal (HPA) axis between groups of rats. Conclusions. a) Low-dose of dexamethasone promote several side effects in metabolism intermediary and chronic exposure to steroid was associated with insulin resistance; b) the regular swimming exercise promoted increased insulin sensitiviry Therefore. exercise can override the dexametasone negative feedback of the HPA axis activation in rats.

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Increase in heterogeneous growth as a result of grouping in the Nile tilapia, Oreochromis niloticus (L.), is presumed to be partially promoted by the social stress imposed by the dominant fish on the subordinates. Such stress may decrease the energy available for growth. In this study, the effect of social stress on carbohydrate metabolism was studied in adult, growing males. All animals were deprived of food during the experimentation period and pairing was imposed for either 2 or 4 days. Glycemia was measured before and after pairing, and muscle and liver glycogen contents were determined only after pairing. Subordinate fish showed the highest consumption of carbohydrate reserves. This response was caused by the social stress imposed which corroborates the idea that metabolic differences promoted by social stress may be involved in the rouping effect on heterogeneous growth in the Nile tilapia.

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The contamination of water by metal compounds is a worldwide environmental problem. This study was undertaken to evaluate the impact of short-term cadmium exposure on metabolic patterns of the freshwater fish Oreochromis niloticus. The fish were exposed to 320, 640, 1280 and 2560 mug/l sublethal concentrations of Cd++ (CdCl2) in water for 7 days. The specific activities of the enzymes phosphofructo kinase (PFK-E.C.2.7.1.11.), lactate dehydrogenase (LDH-E.C.1.1.1.27.) and creatine kinase (CK-E.C.2.7.3.2.) were decreased in white muscle after cadmium treatments, indicating decreases in the capacity of glycolysis in this tissue. Cadmium exposure induced increased glucose concentration in white muscle of fish. on the other hand, cadmium exposure at sublethal concentrations increased phosphofructo kinase and LDH in red muscle of fish. Cadmium significantly decreased total protein concentrations in liver and white muscle regardless of tissue glycogen levels. The data suggest that cadmium acts as a stressor, leading to metabolic alterations similar to those observed in starvation. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

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This work describes the effect of feeding enzymatically hydrolyzed a-lactalbumin on blood sugar, albumin and fatty acids, muscular and hepatic glycogen of rats subjected to physical exercise. Three normoenergetic/normoproteic diets, containing either casein (C), alpha-lactalbumin (L) or alpha-lactalbumin hydrolyzate (H) were fed to thirty male Wistar rats for five weeks. During this period, half of the rats swam for 1 hr daily (T category) while the other half remained sedentary (S category). At the end of training, all rats were required to swim to exhaustion. The results showed that those rats of the T-category consuming diet H reached exhaustion with significantly higher concentrations of serum glucose ([H] 56.0 and [L] 32.3 mg/100ml), serum albumin ([H] 3.8 and [L] 2.1 mg/dl) and muscle glycogen ([H] 2.1 and [L] 0.6 mg/g), while no differences were observed between diets regarding the time of arrival to exhaustion. Results from diets C and L differed minimally. It was concluded that feeding the hydrolyzed protein may result in nutritional advantage to the exercising rat. (C) 1998 Elsevier B.V.

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In order to determine the effect of maternal exercise on maternal nutritional status and fetal growth, young (Y = 45-50 days old) Wistar rats were divided into 4 groups of 5 to 8 animals: control pregnant (CP), control non-pregnant (CNP), exercise-trained (swimming 1 h/day, 5 days/week, for 19 days) pregnant (TP) and exercise-trained non-pregnant (TNP). Four equivalent groups of adult rats (A - 90-100 days old) were also formed. Serum glucose, total protein, albumin, hematocrit and liver glycogen were determined in female rats and pups. There were no statistical differences in serum glucose, total protein and albumin levels, litter size ot birth weight among exercise-trained animals, controls and their respective pups. Hematocrit was significantly lower in pups of exercise-trained young rats than in all other groups (YCP = 38.6 +/- 3.0; YTP = 32.6 +/- 2.1; ACP = 39.0 +/- 2.5; ATP = 39.2 +/- 2.9%). Liver glycogen levels were lower in pregnant than in non-pregnant rats but similar in exercise-trained and control rats of the same age and physiological status (YCNP = 4.1 +/- 0.2; YCP = 2.7 +/- 0.9; YTNP = 4.9 +/- 0.8; YTP = 2.7 +/-0.4; ACNP = 6.1 +/- 0.6; ACP = 3.1 +/- 0.8; ATNP = 6.6 +/- 0.8; ATP = 2.2 +/- 0.9 mg/100 mg). We conclude that pups of adult female rats are spared from the effects of this kind of exercise training during pregnancy. on the other hand, it appears that maternal adaptations to exercise training in young rats are able to preserve only some aspects of pup metabolism.

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OBJECTIVE: the aim of this study was to determine the effects of diets rich in saturated and polyunsaturated fatty acids on metabolic pathways and the relation of metabolic shifting to oxidative stress in cardiac tissue.METHODS: Male Wistar rats (age, 60 d; n = 10) were fed with a control low-fat diet, a diet rich in saturated fatty acids (SFAs), or a diet rich in polyunsaturated fatty acids (PUFAs). After 5 wk of treatment, sera were used for protein and lipid determinations. Protein, glycogen, triacylglycerol, lactate dehydrogenase, citrate synthase, beta-hydroxyacyl coenzyme-A dehydrogenase, catalase, glutathione peroxidase, superoxide dismutase, lipoperoxide, and lipid hydroperoxide were measured in cardiac tissue.RESULTS: the SFA group had higher triacylglycerol, cholesterol, low-density lipoprotein cholesterol, and atherogenic index (ratio of cholesterol to high-density lipoprotein) than did the PUFA and control groups. The PUFA group had low serum cholesterol, triacylglycerol, and low-density lipoprotein cholesterol as compared with the SFA group. SFA increased myocardial lipid hydroperoxide and diminished glutathione peroxidase. Despite the beneficial effects on serum lipids, the PUFA diet led to the highest levels of myocardial lipoperoxide and lipid hydroperoxide and diminished superoxide dismutase and catalase activities. The PUFA effects were related to increased feed efficiency, increased susceptibility to lipoperoxidation, and metabolic shifting in cardiac tissue. PUFA elevated triacylglycerol levels and decreased myocardial glycogen concentrations. The ratios of lactate dehydrogenase to citrate synthase and beta-hydroxyacyl coenzyme-A dehydrogenase to citrate synthase were increased, indicating myocardial reduction of tricarboxylic acid cycle.CONCLUSIONS: PUFAs have been recommended as a therapeutic measure in preventive medicine to lower serum cholesterol, but PUFAs increased oxidative stress in the heart by providing cardiac susceptibility to lipoperoxidation and shifting the metabolic pathway for energy production. The control diet, which was much lower in calories and fat, produced better overall clinical outcomes, better fat profiles, and less oxidative stress than did the diets rich in fatty acids.