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J. oral res. (Impresa) ; 8(5): 363-369, oct. 31, 2019. tab, graf
Article in English | LILACS | ID: biblio-1248086


Objective: Chemotherapy treatment against cancer produce systemic toxicities, among which are those related to important structures of the stomatognathic system and its functional activity. 5 Fluorouracil (5-FU) and cyclophosphamide (Cf) are drugs widely used in solid tumors and in bone marrow transplantation, respectively. The objective of this work was to evaluate the toxicity of these drugs regarding functional activity of the submandibular glands, by measuring the percentage of glycogen consumption in two experimental models. Material and Methods: 84 male Wistar rats aged three months were used, housed in individual cages, with controlled temperature and lighting and ad libitum diet. They were divided into four experimental groups: 1) Control (C); 2) Treated with 5-FU+leucovorin (LV) at 20 and 10mg/Kg of body weight respectively for five consecutive days; 3) treated with Cf i.p. at 50mg/Kg of body weight for two consecutive days; and 4) rats with paired feeding (PF): for five and two days respectively, the amount administered resulted from the average of the ingested food of groups 2 and 3. Both submandibular glands were excised. The submandibular glycogen concentration was analyzed at initial time (t0) and after 60 minutes of mechanical stimulation (t60). Results: the average variation changed significantly between time 0 and 60 in the groups C and PF. (p-value=0.0001), the 5-FU + LV treatment group had an average concentration higher at t0 than groups C and PF, without significant consumption at T60. While group Cf showed a lower average concentration at time 0 with respect to groups C and PF, without significant consumption at T60. Conclusion: 5-FU+LV and Cf affect the metabolism of carbohydrates, decreasing the use of glycogen as a metabolic substrate. In the present experimental model, the toxicity of these drugs affected the functional activity of the submandibular gland.

Objetivo: el tratamiento de quimioterapia contra el cáncer produce toxicidades sistémicas, entre las que se encuentran las relacionadas con estructuras importantes del sistema estomatognático y su actividad funcional. El 5-fluorouracilo (5-FU) y la ciclofosfamida (Cf ) son fármacos ampliamente utilizados en tumores sólidos y en trasplantes de médula ósea, respectivamente. El objetivo de este trabajo fue evaluar la toxicidad de estos fármacos con respecto a la actividad funcional de las glándulas submandibulares, midiendo el porcentaje de consumo de glucógeno en dos modelos experimentales. Material y Métodos: se utilizaron 84 ratas Wistar machos de tres meses de edad, alojadas en jaulas individuales, con temperatura e iluminación controladas y dieta ad libitum. Se dividieron en cuatro grupos experimentales: 1) Control (C); 2) Tratados con 5-FU+leucovorina (LV) a 20 y 10mg/Kg de peso corporal, respectivamente, durante cinco días consecutivos; 3) tratados con Cf i.p. a 50mg/Kg de peso corporal durante dos días consecutivos; y 4) ratas con alimentación por parejas (PF): durante cinco y dos días respectivamente, la cantidad administrada resultó del promedio de los alimentos ingeridos de los grupos 2 y 3. Ambas glándulas submandibulares fueron extirpadas. La concentración de glucógeno submandibular se analizó en el momento inicial (t0) y después de 60 minutos de estimulación mecánica (t60). Resultados: la variación promedio cambió significativamente entre el tiempo 0 y 60 en los grupos C y PF. (p=0,0001), el grupo de tratamiento 5-FU+LV tuvo una concentración promedio más alta en t0 que los grupos C y PF, sin un consumo significativo en T60. Mientras que el grupo Cf mostró una concentración promedio más baja en el tiempo 0 con respecto a los grupos C y PF, sin un consumo significativo en T60. Conclusión: 5-FU + LV y Cf afectan el metabolismo de los carbohidratos, disminuyendo el uso de glucógeno como sustrato metabólico. En el presente modelo experimental, la toxicidad de estos medicamentos afectó la actividad funcional de la glándula submandibular.

Animals , Rats , Submandibular Gland/physiology , Cyclophosphamide/adverse effects , Fluorouracil/adverse effects , Glycogen/metabolism , Rats, Wistar , Cyclophosphamide/therapeutic use , Fluorouracil/therapeutic use , Antineoplastic Agents
Braz. j. biol ; 78(3): 464-471, Aug. 2018. tab
Article in English | LILACS | ID: biblio-951584


Abstract The fish may experience periods of food deprivation or starvation which produce metabolic changes. In this study, adult Rhamdia quelen males were subjected to fasting periods of 1, 7, 14, and 21 days and of refeeding 2, 4, 6, and 12 days. The results demonstrated that liver protein was depleted after 1 day of fasting, but recovered after 6 days of refeeding. After 14 days of fasting, mobilization in the lipids of the muscular tissue took place, and these reserves began to re-establish themselves after 4 days of refeeding. Plasmatic triglycerides increased after 1 day of fasting, and decreased following 2 days of refeeding. The glycerol in the plasma oscillated constantly during the different periods of fasting and refeeding. Changes in the metabolism of both protein and lipids during these periods can be considered as survival strategies used by R. quelen. The difference in the metabolic profile of the tissues, the influence of the period of fasting, and the type of reserves mobilized were all in evidence.

Resumo Os peixes podem sofrer períodos de privação de alimentos ou de fome, que produzem mudanças metabólicas. Neste estudo, jundiás machos adultos foram submetidos a jejum períodos de 1, 7, 14 e 21 dias e realimentação 2, 4, 6, e 12 dias. Os resultados demonstraram que a proteína do fígado foi esgotada depois de um dia de jejum, mas restabeleceu após 6 dias de realimentação. Após 14 dias de jejum, ocorreu a mobilização dos lípidos no tecido muscular sendo que estas reservas começaram a re-estabelecer-se após 4 dias de realimentação. Os triglicérides plasmáticos aumentam após um dia de jejum, e diminuiram após 2 dias de realimentação. O glicerol no plasma oscilou constantemente durante os diferentes períodos de jejum e realimentação. As alterações no metabolismo de proteína e lipídios durante estes períodos podem ser consideradas uma estratégias de sobrevivência utilizada pelo Rhamdia quelen. Sendo que a diferença no perfil metabólico tecidual bem como a influência do período de jejum e o tipo de reserva a ser mobilizada foram observadas neste estudo.

Animals , Male , Catfishes/physiology , Fasting/physiology , Energy Metabolism/physiology , Lipid Metabolism/physiology , Feeding Behavior , Adaptation, Physiological , Fasting/metabolism , Glycogen/metabolism , Lipids/blood , Animal Feed , Muscles
An. acad. bras. ciênc ; 89(3): 1683-1690, July-Sept. 2017. graf
Article in English | LILACS | ID: biblio-886764


ABSTRACT Ischemia is responsible for many metabolic abnormalities in the heart, causing changes in organ function. One of modifications occurring in the ischemic cell is changing from aerobic to anaerobic metabolism. This change causes the predominance of the use of carbohydrates as an energy substrate instead of lipids. In this case, the glycogen is essential to the maintenance of heart energy intake, being an important reserve to resist the stress caused by hypoxia, using glycolysis and lactic acid fermentation. In order to study the glucose anaerobic pathways utilization and understand the metabolic adaptations, New Zealand white rabbits were subjected to ischemia caused by Inflow occlusion technique. The animals were monitored during surgery by pH and lactate levels. Transcription analysis of the pyruvate kinase, lactate dehydrogenase and phosphoenolpyruvate carboxykinase enzymes were performed by qRT-PCR, and glycogen quantification was determined enzymatically. Pyruvate kinase transcription increased during ischemia, followed by glycogen consumption content. The gluconeogenesis increased in control and ischemia moments, suggesting a relationship between gluconeogenesis and glycogen metabolism. This result shows the significant contribution of these substrates in the organ energy supply and demonstrates the capacity of the heart to adapt the metabolism after this injury, sustaining the homeostasis during short-term myocardial ischemia.

Animals , Male , Rabbits , Myocardial Reperfusion Injury/metabolism , Myocardial Ischemia/metabolism , Gluconeogenesis/physiology , Glycogen/metabolism , Myocardial Reperfusion Injury/physiopathology , Myocardial Ischemia/physiopathology , Disease Models, Animal
Indian J Biochem Biophys ; 2014 Aug; 51(4): 321-325
Article in English | IMSEAR | ID: sea-154257


Portulaca oleracea L. has been used as a food and medicinal plant for thousands of years in China. Polysaccharides extracted from P. oleracea L. (POP) are its main bioactive compound and have multiple pharmacological activities. However, anti-fatigue effects of POP have not yet been tested. This study was designed to investigate the anti-fatigue effects of POP in mice using the rotarod and forced swimming tests. The mice were randomly divided into four groups, namely normal control group, low-dose POP supplementation group, medium-dose POP supplementation group and high-dose POP supplementation group. The normal control group received distilled water and the supplementation groups received different doses of POP (75, 150 and 300 mg/kg, respectively). The POP or distilled water was administered orally and daily for 30 day. After 30 days, the rotarod and forced swimming tests were performed and then several biochemical parameters related to fatigue were determined. The data showed that POP prolonged the riding times and exhaustive swimming times of mice, decreasing blood lactic acid and serum urea nitrogen levels, as well as increasing the liver and muscle glycogen contents. These results indicated that POP had the anti-fatigue effects.

Animals , Blood Urea Nitrogen , Fatigue/drug therapy , Glycogen/metabolism , Lactic Acid/blood , Liver/metabolism , Male , Mice , Muscles/metabolism , Polysaccharides/isolation & purification , Polysaccharides/therapeutic use , Portulaca/chemistry , Swimming
Indian J Exp Biol ; 2014 Jul; 52(7): 683-691
Article in English | IMSEAR | ID: sea-153748


Ursolic acid (UA) is a pentacyclic triterpenoid compound that naturally occurs in fruits, leaves and flowers of medicinal herbs. This study investigated the dose-response efficacy of UA (0.01 and 0.05%) on glucose metabolism, the polyol pathway and dyslipidemia in streptozotocin/nicotinamide-induced diabetic mice. Supplement with both UA doses reduced fasting blood glucose and plasma triglyceride levels in non-obese type 2 diabetic mice. High-dose UA significantly lowered plasma free fatty acid, total cholesterol and VLDL-cholesterol levels compared with the diabetic control mice, while LDL-cholesterol levels were reduced with both doses. UA supplement effectively decreased hepatic glucose-6-phosphatase activity and increased glucokinase activity, the glucokinase/glucose-6-phosphatase ratio, GLUT2 mRNA levels and glycogen content compared with the diabetic control mice. UA supplement attenuated hyperglycemia-induced renal hypertrophy and histological changes. Renal aldose reductase activity was higher, whereas sorbitol dehydrogenase activity was lower in the diabetic control group than in the non-diabetic group. However, UA supplement reversed the biochemical changes in polyol pathway to normal values. These results demonstrated that low-dose UA had preventive potency for diabetic renal complications, which could be mediated by changes in hepatic glucose metabolism and the renal polyol pathway. High-dose UA was more effective anti-dyslipidemia therapy in non-obese type 2 diabetic mice.

Animals , Antineoplastic Agents, Phytogenic/pharmacology , Blotting, Western , Diabetes Complications/etiology , Diabetes Complications/pathology , Diabetes Complications/prevention & control , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Dyslipidemias/drug therapy , Dyslipidemias/etiology , Dyslipidemias/pathology , Glucokinase/metabolism , Glucose/metabolism , Glucose Transporter Type 2/genetics , Glucose-6-Phosphatase/metabolism , Glycogen/metabolism , Hyperglycemia/complications , Kidney Diseases/etiology , Kidney Diseases/pathology , Kidney Diseases/prevention & control , Male , Mice , Mice, Inbred ICR , Mice, Inbred NOD , Polymers/metabolism , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Triterpenes/pharmacology
Indian J Biochem Biophys ; 2013 Aug; 50(4): 326-329
Article in English | IMSEAR | ID: sea-148615


The in vivo anti-fatigue activity of the total flavonoids from sweet potato [Ipomoea batatas (L.) Lam.] leaf was investigated in male Kunming mice. The total flavonoids from sweet potato leaf (TFSL) were orally administered at doses of 50, 100 and 200 mg/kg for 4 weeks and the anti-fatigue effect was studied using a weight-loaded swimming test, along with the determination of serum urea nitrogen (SUN), blood lactic acid (BLA) and hepatic and muscle glycogen contents. The results showed that TFSL had significant anti-fatigue effects. TFSL extended the exhaustive swimming time, effectively inhibited the increase of BLA, decreased the level of SUN and increased the hepatic and muscle glycogen content of mice. Thus, TFSL may have potential as an anti-fatigue agent.

Animals , Blood Urea Nitrogen , Body Weight/drug effects , Fatigue/blood , Fatigue/drug therapy , Fatigue/metabolism , Flavonoids/isolation & purification , Flavonoids/pharmacology , Flavonoids/therapeutic use , Glycogen/metabolism , Ipomoea batatas/chemistry , Lactic Acid/blood , Liver/drug effects , Liver/metabolism , Male , Mice , Muscles/drug effects , Muscles/metabolism , Plant Leaves/chemistry , Swimming
Braz. j. med. biol. res ; 46(7): 559-566, ago. 2013. graf
Article in English | LILACS | ID: lil-682396


Hepatic progenitor cells (HPCs) are a potential cell source for liver cell transplantation but do not function like mature liver cells. We sought an effective and reliable method to induce HPC maturation. An immortalized HP14.5 albumin promoter-driven Gaussian luciferase (ALB-GLuc) cell line was established from HPCs isolated from fetal mouse liver of post coitus day 14.5 mice to investigate the effect of induction factors on ALB promoter. HP14.5 parental cells were cultured in DMEM with different combinations of 2% horse serum (HS), 0.1 µM dexamethasone (DEX), 10 ng/mL hepatic growth factor (HGF), and/or 20 ng/mL fibroblast growth factor 4 (FGF4). Trypan blue and crystal violet staining were used to assess cell proliferation with different induction conditions. Expression of hepatic markers was measured by semi-quantitative RT-PCR, Western blot, and immunofluorescence. Glycogen storage and metabolism were detected by periodic acid-Schiff and indocyanine green (ICG) staining. GLuc activity indicated ALB expression. The combination of 2% HS+0.1 µM Dex+10 ng/mL HGF+20 ng/mL FGF4 induced the highest ALB-GLuc activity. Cell proliferation decreased in 2% HS but increased by adding FGF4. Upon induction, and consistent with hepatocyte development, DLK, AFP, and CK19 expression decreased, while ALB, CK18, and UGT1A expression increased. The maturity markers tyrosine aminotransferase and apolipoprotein B were detected at days 3 and 6 post-induction, respectively. ICG uptake and glycogen synthesis were detectable at day 6 and increased over time. Therefore, we demonstrated that HPCs were induced to differentiate into functional mature hepatocytes in vitro, suggesting that factor-treated HPCs may be further explored as a means of liver cell transplantation.

Animals , Mice , Cell Differentiation/drug effects , Embryo, Mammalian/drug effects , Hepatocytes/cytology , Liver/cytology , Stem Cells/drug effects , Antigens, Differentiation/analysis , Apolipoproteins B/isolation & purification , Cell Proliferation , Dexamethasone/administration & dosage , Fibroblast Growth Factors/administration & dosage , Gentian Violet , Glycogen/metabolism , Hepatocyte Growth Factor/administration & dosage , Indocyanine Green/pharmacokinetics , Primary Cell Culture/methods , Reverse Transcriptase Polymerase Chain Reaction , Stem Cells/cytology , Trypan Blue , Tyrosine Transaminase/isolation & purification
Einstein (Säo Paulo) ; 11(1): 83-87, jan.-mar. 2013. graf, tab
Article in Portuguese | LILACS | ID: lil-670309


OBJETIVO: Avaliar as ações da ingestão alcoólica e da neuroestimulação sobre a reserva de glicogênio muscular, o peso corporal, a glicemia sanguínea e o peso do músculo sóleo. MÉTODOS: Vinte ratos machos foram distribuídos em quatro grupos experimentais (n=5), a saber, Controle, Etanol, Eletroestimulado e Etanol+Eletroestimulado. A pesquisa durou 22 dias. Os grupos submetidos ao uso do etanol receberam a substância diluída em água, que foi consumida durante todo o período experimental. Os grupos que receberam a eletroestimulação, sob sedação para o procedimento, tiveram o membro posterior esquerdo tricotomizado, de forma que a aplicação da corrente foi realizada diariamente, por 7 dias, em sessões de 20 minutos. Na sequência, após a indução ao alcoolismo e a aplicação da estimulação elétrica nos correspondentes grupos, os animais foram eutanasiados, para que os músculos fossem encaminhados para análise do glicogênio. RESULTADOS: O Grupo Etanol apresentou menor peso corporal quando comparado ao Controle e ao Eletroestimulado; o Grupo Etanol+Eletroestimulado apresentou peso menor quando comparado aos Grupos Controle e Eletroestimulado, mas esteve em melhor situação ao se comparar ao Grupo Etanol. Quanto à capitação glicogênica, notou-se que o Grupo Etanol demonstrou quadro de resistência à capitação da glicose sanguínea, sendo que o etanol eletroestimulado demonstrou melhor captação que os demais grupos. Em relação ao peso da musculatura, pode-se observar que o Grupo Etanol apresentou menor peso que o Controle e que o Grupo Eletroestimulado apresentou aumento da pesagem ao comparar-se aos grupos Controle e Etanol, respectivamente. Já o Grupo Etanol+Eletroestimulado não apresentou diferença significativa em relação ao Controle, mas teve melhores resultados ao contrapesar com o Grupo Etanol. CONCLUSÃO: A exposição crônica ao álcool apresentou relação direta com a redução do peso do muscular e corpóreo, e da captação de glicogênio e de suas reservas musculares, além de favorecer inúmeras desordens orgânicas, podendo, assim, interferir em processos de reabilitação.

OBJECTIVE: To evaluate the effects of alcoholic ingestion and neurostimulation on the muscle glycogen reserve, body weight, blood sugar, and weight of the soleus muscle. METHODS: Twenty male rats were distributed into four experimental groups (n=5), namely, Control, Ethanol, Electrostimulated, and Ethanol+Electrostimulated. The study lasted for 22 days. The groups submitted to the use of ethanol received the substance diluted in water, which was consumed during the entire experimental period. The groups that received electrostimulation, undersedationfor the procedure, had their left hind leg shaved, and the current was applied daily for 7 days, in 20-minute sessions. Next, after induced alcoholism and electrical stimulation in the corresponding groups, the animals were euthanized so that their muscles could be sent for glycogen analysis. RESULTS: The Ethanol group displayed a lower body weight when compared to the Control and Electrostimulated groups; the Ethanol+Electrostimulated groups had a lower body weight compared to the Control and Electrostimulated groups, but were in a better situation when compared to the Ethanol group. As to glycogen capture, it was noted that the Ethanol group demonstrated resistance to blood glucose capture, whereas the Ethanol Electrostimulated group showed better capture than the other groups. As to muscle weight, it was observed that the Ethanol group had a lower weight than did the Controls, and that the Electrostimulated group weight greater when compared to the Control and Ethanol groups, respectively. On the other hand, the Ethanol+Electrostimulated groups showed no significant difference relative to the Controls, but had better results when compared to the Ethanol group. CONCLUSIONS: Chronic exposure to alcohol showed a direct relationship with reduced muscle and body weight, and in glycogen capture and muscle reserves, besides favoring innumerous organic disorders, thus interfering in rehabilitation processes.

Animals , Rats , Electric Stimulation , Ethanol/adverse effects , Glycogen/metabolism
Indian J Exp Biol ; 2013 Jan; 51(1): 65-72
Article in English | IMSEAR | ID: sea-147569


Antihyperglycemic potential of hyperin at 25 and 50 mg/kg doses for 30 days to streptozotocin induced diabetic rats has been reported. In oral glucose tolerance test, hyperin treated rats showed a significant reduction in blood glucose level after 120 min. It was found that hyperin exhibited dose dependent and significant antihyperglycemic activity in streptozotocin induced diabetic rats which were nearly similar with standard drug glybenclamide. Activities of glucose-6-phosphatase, fructose-1,6-bisphosphatase, glycogen phosphorylase, glycosylated haemoglobin and level of serum urea and creatinine were significantly decreased in hyperin supplemented diabetic rats, dose dependently. Activities of hexokinase and glycogen synthase were increased with augmentation in liver glycogen, insulin and haemoglobin content in hyperin treated diabetic rats. General hematological parameters did not show any significant change in hyperin treated diabetic rats hence it is safe at these doses. Histopathological studies showed significant morphological changes in pancreatic β-cells of streptozotocin induced diabetic rats. A decreased number of secretory granules of β- cells were observed in diabetic rats and these pathological abnormalities were normalized after treatment with hyperin and standard drug glybenclamide. Further, hyperin decreases significant in serum total cholesterol, triglyceride, low density lipoprotein, very low density lipoprotein levels coupled with elevation of high density lipoprotein in diabetic rats. These results suggest that hyperin has a pivotal role in blood glucose level in streptozotocin induced hyperglycemia by improving the function of pancreatic islets and increasing glycolysis and decreasing gluconeogenesis.

Animals , Diabetes Mellitus, Experimental/drug therapy , Glucose Tolerance Test , Glyburide/pharmacology , Glycogen/metabolism , Hexokinase/metabolism , Hypoglycemic Agents/pharmacology , Insulin/metabolism , Lipids/chemistry , Liver/metabolism , Male , Models, Chemical , Quercetin/analogs & derivatives , Quercetin/chemistry , Quercetin/metabolism , Quercetin/pharmacology , Rats , Rats, Wistar , Rhododendron/metabolism
Rev. bras. cir. cardiovasc ; 27(4): 621-630, out.-dez. 2012. ilus, tab
Article in English | LILACS | ID: lil-668125


OBJECTIVES: The present investigation aimed to study the protective effect of intermittent normothermic cardioplegia in rabbit's hypertrophic hearts. METHODS: The parameters chosen were 1) the ratio heart weight / body weight, 2) the myocardial glycogen levels, 3) ultrastructural changes of light and electron microscopy, and 4) mitochondrial respiration. RESULTS: 1) The experimental model, coarctation of the aorta induced left ventricular hypertrophy; 2) the temporal evolution of the glycogen levels in hypertrophic myocardium demonstrates that there is a significant decrease; 3) It was observed a time-dependent trend of higher oxygen consumption values in the hypertrophic group; 4) there was a significant time-dependent decrease in the respiratory coefficient rate in the hypertrophic group; 5) the stoichiometries values of the ADP: O2 revealed the downward trend of the values of the hypertrophic group; 6) It was possible to observe damaged mitochondria from hypertrophic myocardium emphasizing the large heterogeneity of data. CONCLUSION: The acquisition of biochemical data, especially the increase in speed of glycogen breakdown, when anatomical changes are not detected, represents an important result even when considering all the difficulties inherent in the process of translating experimental results into clinical practice. With regard to the adopted methods, it is clear that morphometric methods are less specific. Otherwise, the biochemical data allow detecting alterations of glycogen concentrations and mitochondria respiration before the morphometric alterations should be detected.

OBJETIVOS: O presente estudo teve como objetivo estudar o efeito protetor da cardioplegia normotérmica intermitente em corações hipertróficos de coelhos. MÉTODOS: Os parâmetros escolhidos foram: 1) relação peso cardíaco/peso corporal; 2) níveis de glicogênio nos músculos cardíacos; 3) alterações ultraestruturais por microscopia óptica e eletrônica; e 4) respiração mitocondrial. RESULTADOS: 1) O modelo experimental de coarctação da aorta induziu hipertrofia ventricular esquerda; 2) a evolução temporal dos níveis de glicogênio no miocárdio hipertrófico demonstra que há diminuição significativa; 3) observou-se tendência dependente do tempo para maiores valores do consumo de oxigênio para o grupo hipertrófico; 4) houve diminuição dependente do tempo da taxa de coeficiente respiratório no grupo hipertrófico; 5) os valores estequiométricos da ADP: O2 revelou a tendência decrescente no grupo hipertrófico; 6) observaram-se lesões mitocondriais do miocárdio hipertrófico, enfatizando a grande heterogeneidade dos dados. CONCLUSÃO: A aquisição de dados bioquímicos, principalmente o aumento na velocidade de quebra do glicogênio, quando mudanças anatômicas não são detectadas, representa um resultado importante, mesmo quando se consideram todas as dificuldades inerentes ao processo translacional de resultados experimentais para a prática clínica. No que diz respeito aos métodos adotados, é evidente que os métodos morfométricos são menos específicos. Os dados bioquímicos permitem a detecção de alterações das concentrações de glicogênio e respiração mitocondrial antes das alterações morfométricas serem detectadas.

Animals , Rabbits , Body Weight/physiology , Cardiomyopathy, Hypertrophic/pathology , Glycogen/metabolism , Heart Arrest, Induced/methods , Mitochondria, Heart/metabolism , Myocardial Reperfusion Injury/prevention & control , Myocardium/ultrastructure , Cardiomyopathy, Hypertrophic/metabolism , Disease Models, Animal , Heart/anatomy & histology , Myocardium/metabolism , Organ Size/physiology , Oxygen Consumption/physiology , Random Allocation , Statistics, Nonparametric
Yonsei Medical Journal ; : 1142-1146, 2012.
Article in English | WPRIM | ID: wpr-183501


PURPOSE: Glycogen rich clear cell carcinoma (GRCC) of the breast is a rare subtype of invasive ductal carcinoma and involves a poor prognosis. In the literature, less than 150 cases have been reported. Many researchers have attempted to characterize GRCC according to electron microscope, flow cytometry, or clinical data. However, an organized study of the immunophenotype of GRCC has yet to be reported. MATERIALS AND METHODS: Here, we present three cases of GRCC and their immunohistochemical profiles. RESULTS: Histologically, all three cases contained periodic acid stain (PAS) positive and d-PAS labile granules in their clear cytoplasm. Case I showed positivity for only estrogen receptor (ER) and c-erbB2. Case II exhibited positivity for progesterone receptor and negativity for ER and c-erbB2. Case III presented with triple negative invasive carcinoma. The expression pattern of E-cadherin was concordant with epidermal growth factor receptor and c-kit, but discordant with ki-67. Among these three cases, p53-positive cases exhibited a low proliferative index (ki-67: 15%), while p53-negative cases showed a high proliferative index (ki-67: 50-60%). CONCLUSION: In conclusion, the immunophenotype of GRCC is not uniform, but is similar to that of conventional ductal carcinoma.

Adenocarcinoma, Clear Cell/classification , Breast Neoplasms/classification , Female , Glycogen/metabolism , Humans , Immunohistochemistry , Immunophenotyping/methods , Ki-67 Antigen/metabolism , Proto-Oncogene Proteins c-kit/metabolism , ErbB Receptors/metabolism , Receptor, ErbB-2/metabolism , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism
Arq. bras. cardiol ; 95(6): 720-725, dez. 2010. graf, tab
Article in Portuguese | LILACS | ID: lil-572200


FUNDAMENTO: Considerou-se o uso indiscriminado de esteroides tanto por atletas de elite quanto por praticantes de atividades físicas. OBJETIVO: Avaliar os efeitos do decanoato de nandrolona sobre o perfil eletrocardiográfico, conteúdo glicogênico e de proteínas totais dos músculos cardíacos e esqueléticos, bem como as concentrações plasmática de albumina. MÉTODOS: Os animais do grupo tratado receberam a droga na concentração 5 mg/kg pela via subcutânea, duas vezes por semana, durante três semanas. Uma vez por semana, os ratos foram anestesiados com Pentobarbital sódico (50 mg/kg, ip) e submetidos à avaliação por meio do eletrocardiograma (ECG). Após o período experimental, amostras dos músculos cardíaco (ventrículo esquerdo - VE), sóleo (S), gastrocnêmio branco (GB), gastrocnêmio vermelho (GV), peitoral (P), intercostal (IC) e diafragma (D) foram prontamente coletadas e analisadas. Os dados (média ± epm) foram avaliados de acordo com ANOVA, segundo teste de Tukey (p>0,05). RESULTADOS: Os ratos do grupo tratado apresentaram alterações nos seguintes parâmetros cardíacos: intervalo QRS, intervalo QTc e frequência cardíaca, caracterizados por um aumento desses, tendo o ápice no intervalo da semana de pré-tratamento para a primeira semana. As reservas de glicogênio no VE apresentaram aumento de 127 por cento. Em relação à quantidade de proteínas totais, a diferença significativa foi constatada no S, GV e D. Quanto ao perfil bioquímico e ao hematócrito, foi observado um aumento na porcentagem de eritrócitos. CONCLUSÃO: O estudo mostra que importantes alterações cardíacas são deflagradas precocemente, sugerindo uma hierarquia na sequência de modificações que comprometem a homeostasia do organismo.

BACKGROUND: We considered both the indiscriminate use of steroids by top athletes and by physically active individuals. OBJECTIVE: To evaluate the effects of nandrolone decanoate on the electrocardiographic profile, glycogen content and total-protein profile of skeletal and cardiac muscles, as well as the plasma albumin concentrations. METHODS: The drug was administered subcutaneously, at a concentration of 5 mg/kg, twice a week for three weeks, to animals in the treated group. Once a week, the rats were anesthetized with sodium pentobarbital (50 mg/kg, ip) and they underwent an electrocardiogram (ECG). After the trial period, samples of the cardiac muscle (left ventricle - LV), soleus muscle (S), white gastrocnemius muscle (WG), red gastrocnemius muscle (RG), pectoral muscle (P), intercostal muscle (IC) and diaphragm muscle (D) were promptly collected and analyzed. An analysis of variance (ANOVA) and then a Tukey test (p>0.05) were carried out to assess the data (mean ± sem). RESULTS: There were changes in the following parameters of rats in the treated group: QRS interval, QTc interval and heart rate, characterized by an increase in these parameters, with the peak being reached in the period between the pre-treatment week and the first week. There was an increase of 127 percent in glycogen reserves in the LV. In relation to the total-protein amount, the significant difference was found in S, RG and D. As for the hematocrit and biochemical profile, it was possible to notice an increase in the percentage of erythrocytes. CONCLUSION: The study shows that major cardiac changes are triggered at an early stage, which indicates a hierarchy in the sequence of changes that compromise the homeostasis of the body.

FUNDAMENTO: Se consideró el uso indiscriminado de esteroides tanto por atletas de elite como por practicantes de actividades físicas. OBJETIVO: Evaluar los efectos del decanoato de nandrolona sobre el perfil electrocardiográfico, contenido glicogénico y de proteínas totales de los músculos cardíacos y esqueléticos, así como las concentraciones plasmática de albúmina. MÉTODOS: Los animales del grupo tratado recibieron la droga en la concentración 5mg/kg por vía subcutánea, dos veces por semana, durante tres semanas. Una vez por semana, los ratones fueron anestesiados con Pentobarbital sódico (50mg/Kg, ip) y sometidos a evaluación por medio de electrocardiograma (ECG). Después del período experimental, muestras de los músculos cardíaco (ventrículo izquierdo - VI), sóleo (S), gastrocnemio blanco (GB), gastrocnemio rojo (GV), pectoral (P), intercostal (IC) y diafragma (D) fueron colectadas y analizadas. Los datos (media±epm) fueron evaluados de acuerdo con ANOVA, segundo test de Tukey (p>0,05). RESULTADOS: Los ratones del grupo tratado presentaron alteraciones en los siguientes parámetros cardíacos: intervalo QRS, intervalo QTc y frecuencia cardíaca, caracterizados por un aumento de estos, teniendo el ápice en el intervalo de la semana de pretratamiento a la primera semana. Las reservas de glicógeno en el VI presentaron aumento de 127 por ciento. En relación a la cantidad de proteínas totales, una diferencia significativa fue constatada en el S, GV y D. En cuanto al perfil bioquímico y al hematocrito, fue observado un aumento en el porcentaje de eritrocitos. CONCLUSIÓN: El estudio muestra que importantes alteraciones cardíacas son provocadas precozmente, sugiriendo una jerarquía en la secuencia de modificaciones que comprometen la homeostasia del organismo.

Animals , Rats , Anabolic Agents/pharmacology , Glycogen/metabolism , Heart Rate/drug effects , Heart/drug effects , Muscle, Skeletal/drug effects , Nandrolone/analogs & derivatives , Analysis of Variance , Albumins/metabolism , Electrocardiography , Heart Conduction System/drug effects , Muscle Proteins/metabolism , Muscle, Skeletal/metabolism , Myocardium/metabolism , Nandrolone/pharmacology , Random Allocation , Rats, Wistar
Rev. bras. ginecol. obstet ; 32(4): 163-168, abr. 2010. ilus, tab
Article in Portuguese | LILACS | ID: lil-550763


OBJETIVO: avaliar a eficácia do modelo de RCIU por ligadura da artéria uterina simulando insuficiência placentária em ratos. MÉTODOS: fetos de ratas prenhes Sprague-Dawley foram divididos em três grupos: RCIU (restrição de crescimento intrauterino), com fetos submetidos à ligadura da artéria uterina com 18,5 dias de gestação (termo = 22 dias), C-RCIU (controle da restrição), com fetos do corno contralateral à ligadura, CE (Controle Externo), com fetos de ratas sem manipulação. Com 21,5 dias de gestação, foi realizada cesárea, os fetos foram pesados e dissecados para análise morfométrica e histológica do fígado, intestino e rins. RESULTADOS: os dados morfométricos avaliados mostraram o peso corpóreo (PC), hepático (PH) e intestinal (PI) dos fetos com RCIU menor que C-RCIU e CE (p<0,001). O peso placentário (PP), renal (PR) e as relações PH/PC, PI/PC e PR/PC não se alteraram. A espessura renal foi menor nos fetos com RCIU (p<0,001) e houve diminuição da camada mucosa e submucosa intestinal (p<0,05). A avaliação histológica mostrou diminuição do glicogênio hepático nos fetos com RCIU em relação aos grupos C-RCIU e CE. CONCLUSÕES: o modelo descrito foi eficiente e causou RCIU fetal simétrica com diminuição da maioria dos órgãos, especialmente do peso hepático, e alteração nos depósitos de glicogênio.

PURPOSE: to evaluate the effectiveness of the IUGR model by uterine artery ligation mimicking placental insufficiency in rats. METHODS: sprague-Dawley rat fetuses were divided into three groups: IUGR (intrauterine growth restriction), with fetuses in the right horn of pregnant rats subjected to right uterine artery ligation at 18.5 days of gestation (term = 22 days); C-IUGR (control of restriction), with control fetuses in the left horn, and EC (external control), with fetuses of intact rats. Animals were harvested by cesarean section at day 21.5 days of gestation. Fetuses were weighed and then sacrificed. The intestine, liver, kidney and placenta were weighed and dissected for morphometric and histological analysis. RESULTS: the morphometric data showed decreased body weight (BW), liver weight (LW) and intestinal weight (IW) of fetuses with IUGR compared to C-IUGR and EC (p<0.001). The placental weight (PW), renal weight (RW) and LW/BW, IW/BW, and RW/BW ratios did not change. IUGR fetuses had decreased kidney thickness (p<0.001) and decreased thickness of the intestinal mucosa and submucosa (p<0.05). Histological evaluation showed reduction of liver glycogen storage in fetuses with IUGR compared to C-IUGR and CE. CONCLUSIONS: the model described was efficient and caused symmetric fetal IUGR with decreased size of most organs, especially the liver, and changes in glycogen stores.

Animals , Rats , Disease Models, Animal , Fetal Growth Retardation/metabolism , Fetal Growth Retardation/pathology , Glycogen/metabolism , Intestines/pathology , Kidney/pathology , Liver/metabolism , Intestines/embryology , Kidney/embryology , Liver/embryology , Organ Size , Rats, Sprague-Dawley
Rev. chil. nutr ; 37(1): 118-122, mar. 2010. tab
Article in Spanish | LILACS | ID: lil-577377


Nutritional strategies are one of basic fundaments of performance in sports. In soccer, like in the majority of professional sports, nutritional control of players is very important. This work presents a general proposal of the structure of the diet for training and the competition based in caloric disassociation, to achieve muscular surcharge of carbohydrates. Nutritional strategies based in the disassociation of the diet, according to metabolic needs of the competition and the training have demonstrated a great efficacy in performance improvement of players. Numerous studies report about metabolic needs of soccer during a game and during training. It has been demonstrated than the super-compensation of carbohydrates is the most effective nutritional strategy.

Las estrategias nutricionales son uno de los pilares básicos del rendimiento en el deporte de competición. En el fútbol como en la mayoría de los deportes profesionales, el control nutricional del jugador ha cobrado una gran importancia. En este trabajo se presenta una propuesta general de la estructura de la dieta para el entrenamiento y la competición basada en la disociación calórica buscando una sobrecarga de hidratos de carbono. Estrategias nutricionales basadas en la disociación de principios inmediatos en función de las necesidades metabólicas de la competición y el entrenamiento, se han demostrado eficaces en la mejora del rendimiento de los deportistas. En el fútbol se han reportado numerosos estudios que describen las necesidades metabólicas durante un partido y durante los entrenamientos. La supercompensación de hidratos de carbono es el tipo de estrategia nutricional que ha demostrado ser más eficaz.

Humans , Adult , Dietary Carbohydrates/administration & dosage , Soccer/physiology , Athletic Performance , Energy Intake , Glycogen/metabolism , Nutritional Requirements
Rev. bras. cir. cardiovasc ; 23(4): 530-533, out.-dez. 2008. tab
Article in English | LILACS | ID: lil-506037


INTRODUÇÃO: Hipotermia corporal induzida e resfriamento do miocárdio são métodos efetivos em relação à proteção domiocárdio durante cirurgias cardíacas e isquemia. É descrito na literatura que a exposição a temperaturas extremamente baixas causa comprometimentos de miofilamentos e de cristas mitocondriais em cardiomiócitos, entretanto, nenhum estudo analisou os efeitos do estresse pelo frio no tamanho do núcleo dos cardiomiócios. OBJETIVOS: Analisar os efeitos do estresse agudo pelo frio sobre o tamanho do núcleo dos cardiomiócitos. MÉTODOS: O estudo foi realizado em ratos Wistar adultos, pesando 300-310g (n=20). Os ratos foram divididos em dois grupos: 1) Controle (CON) e; 2) Hipotermia induzido (IH). Os animais do grupo IH foram expostos a uma temperatura controlada de -8ºC, durante 4 horas uma única vez. Foi realizada análise histológica de fígados e glândulas adrenais para examinar a condição de estresse. O tamanho do núcleo dos cardiomiócitos foi examinado por três investigadores independentes com o mesmo critério padronizado e posteriormente analisado pelo coeficiente de correlação de Bartko (R>0,75=concordância positiva). Teste t de Student foi aplicado. O nível de significância foi considerado como P<0,05. RESULTADOS: O grupo exposto ao estresse pelo frio apresentou maior depleção de lipídio nas glândulas adrenais (P<0,05) e de glicogênio no fígado (P<0,05). O grupo induzido à hipotermia mostrou menor volume do núcleo de seus cardiomiócitos (108 + 1,7 µm³; P<0,05), reduziu em 76 por cento comparado ao grupo controle (142 + 2,3 µm³). Correlação de Bartko: CON=0,44; IH=0,96, a variação entre a média dos grupos foi significativamente diferente. CONCLUSÃO: Esses resultados sugerem que a exposição ao estresse agudo pelo frio induz redução do núcleo dos cardiomiócitos em ratos.

INTRODUCTION: Total body induced hypothermia and myocardial cooling are effective methods regarding myocardial protection during heart surgery and ischemia. It is described in previous studies that extreme low temperature exposure causes mitochondrial cristae and myofilament disarrangement in cardiomyocytes, however, no investigation has analyzed the effects of cold stress on nuclear size of cardiomyocytes. OBJECTIVES: To evaluate the effects of acute cold stress exposure on the nuclear size of cardiomyocytes in rats. METHODS: The experimental study procedures were performed on 300-310g adult male Wistar rats. Rats (n=20) were divided into two groups: 1) Control (CON) and; 2) Induced hypothermic (IH) group. Animals of IH group were exposed during 4 hours once at a controlled temperature of - 8ºC. It was performed histological analysis of liver and adrenal gland to examine the stress condition of animals. Cardiomyocytes nucleus size were examined by three independent investigators with the same and standardized criteria and analyzed by Bartko's intra-class correlation coefficient (R>0.75 = positive concordance). Student's t test was applied. The significance level was set at P<0.05. RESULTS: The induced hypothermic group presented higher lipid depletion in adrenal gland cells (P<0.05) and higher glycogen depletion in liver glycogen (P<0.05). The experimental group showed lower cardiomyocytes nuclear volume (108 + 1.7 µm³; P<0.05), it decreased in 76 percent compared to the control group (142 + 2.3 µm³). Bartko's correlation: CON=0.44; IH=0.96, variation analysis between group's means differences was significant. CONCLUSION: These data suggest that acute cold stress exposure induces cardiomyocytes nucleus size reduction in rats.

Animals , Male , Rats , Cell Nucleus Size , Cold Temperature/adverse effects , Myocytes, Cardiac/ultrastructure , Adrenal Glands/metabolism , Adrenal Glands/pathology , Glycogen/metabolism , Heart Ventricles , Hypothermia, Induced/adverse effects , Liver/metabolism , Liver/pathology , Rats, Wistar , Stress, Physiological/physiology
J Environ Biol ; 2008 Nov; 29(6): 887-92
Article in English | IMSEAR | ID: sea-113701


The extensive use of pesticides to control agricultural pests poses a serious threat to many non-target organisms of the aquatic environment such as the freshwater crab, B. guerini. The deleterious influence of the pesticide causes physiological, biochemical, histological and such other disorders in the animal exposed. In the present study impact of an organophosphate pesticide, monocrotophos and neuroendocrine regulation on the biochemical contents of hepatopancreas of B. guerini has been studied. Experimental studies revealed that glycogen and protein content decreased in normal crabs when exposed to sub lethal concentrations of monocrotophos, while lipid content was increased. In the ablated and pesticide exposed crabs glycogen, protein and lipid contents decreased. In case of ablated and exposed crabs when injected with eyestalk extract, glycogen and protein contents declined, whereas lipid content hiked. It was observed that glycogen, protein and lipid contents in eyestalk extract injected crabs were similar to those of normal exposed crabs. This indicates the vital role of eyestalk in the regulation of biochemical contents. Histological studies of the hepatopancreas indicate structural changes such as large number of vacuolated cells and phagocytes when exposed to the pesticide.

Animals , Brachyura/cytology , Fresh Water/chemistry , Glycogen/metabolism , Hepatopancreas/cytology , Lipid Metabolism/drug effects , Monocrotophos/toxicity , Neurosecretory Systems/drug effects , Pesticides/toxicity , Proteins/metabolism , Water Pollutants, Chemical/toxicity
J Environ Biol ; 2008 Sep; 29(5): 721-4
Article in English | IMSEAR | ID: sea-113382


In order to evaluate the impact of copper on the energetics of a fish, the levels of glucose, glycogen, pyruvate and lactate, the rate of tissue oxygen consumption and the activities of glycogen phosphorylase, isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) were estimated in the whole body of the fry of Cyprinus carpio immediately after 1, 7, 15 and 30 days on exposure to a sublethal concentration of copper 0.08 mgl(-1) at pH 7.5 (normal), 6.0 (weak acidic) and 9.0 (weak alkaline). Aprogressive increase in glucose level and glycogen phosphorylase activity with the corresponding decrease in glycogen level over the time of exposure at pH 7.5 indicated glycogenolysis. Increase in the rate of oxygen consumption, pyruvate level and ICDH and SDH activities at days 1 and 7 (day 1 > 7) followed by their decrease at days 15 and 30 (day 15 < 30) at pH 7.5 indicated an initial elevation in the energetics of the fish fry with a gradual suppression of it on prolonged exposure. During this period the animal might have relied more on energetically less efficient glycolysis as evident by the progressive increase in the level of lactate and LDH activity. The degree of glycogenolysis was relatively more at pH 6.5 than at pH 7.5. At that pH, a progressive decrease in glucose level with an increase in the pyruvate and lactate levels and in LDH activity and a decrease in the rate of oxygen consumption and ICDH and SDH activities revealed greater reliance of the fish on anaerobic glycolysis than on oxidative metabolism. At pH 9.0 also the fish fry initially exhibited glycogenolysis, but gradually it came to normal on day 30 (day 1 > 7 > 15 > 30). Decrease in the glucose level, increase in pyruvate level, rate of oxygen consumption, and ICDH and SDH activities at all the days of exposure suggested an elevation in oxidative metabolism, but it also came to normal on prolonged exposure. Even the lactate level and LDH activity initially increased but gradually reached to normal on day 30. These results indicated that copper suppresses the energetics of the fish fry at pH 6.0, elevates at pH 9.0 relative to the changes at pH 7.5 suggesting that the toxicity of copper is dependent on pH of the water.

Animals , Carps/growth & development , Copper/toxicity , Energy Metabolism/drug effects , Glucose/metabolism , Glycogen/metabolism , Glycogen Phosphorylase/metabolism , Hydrogen-Ion Concentration , Isocitrate Dehydrogenase/metabolism , L-Lactate Dehydrogenase/metabolism , Oxidation-Reduction , Oxygen Consumption/drug effects , Succinate Dehydrogenase/metabolism , Water Pollutants, Chemical/toxicity
Rev. Assoc. Med. Bras. (1992) ; 54(3): 272-278, maio-jun. 2008. tab
Article in Portuguese | LILACS | ID: lil-485613


INTRODUÇÃO: Epilepsia é uma desordem neurológica caracterizada por crises espontâneas e recorrentes, que afeta de 2 por cento a 3 por cento da população mundial. As crises epilépticas refletem atividade elétrica anormal e paroxística, preferencialmente em uma ou várias áreas do córtex cerebral, que podem ser causadas por inúmeras patologias estruturais ou neuroquímicas. Dentre os importantes estudos das últimas décadas no campo da epileptologia, destaca-se a identificação de genes associados a certos tipos de epilepsia. OBJETIVO: Nesta revisão, descrevemos as principais alterações genéticas associadas ao processo epileptogênico, discutindo as mais recentes descobertas e suas contribuições para a compreensão das bases genéticas das epilepsias idiopáticas monogênicas (EIM) e das epilepsias geneticamente complexas. RESULTADOS E CONCLUSÃO: Estudos de ligação e associação mostram que alterações em genes que codificam canais iônicos são as principais causas genéticas das epilepsias idiopáticas monogênicas e de predisposição nas epilepsias geneticamente complexas. Além disso, as síndromes nas quais a epilepsia é um aspecto importante do quadro clínico podem ser provocadas por genes envolvidos em diferentes vias celulares, tais como: migração neuronal, metabolismo de glicogênio e cadeia respiratória. Portanto, acredita-se que diferentes categorias de genes possam atuar na determinação do traço epiléptico. A identificação de tais famílias de genes não apenas nos ajudará a entender as vias moleculares associadas à hiperexcitabilidade neuronal e ao processo epileptogênico, mas também poderá conduzir ao desenvolvimento de novas e mais precisas estratégias de tratamento da epilepsia.

INTRODUCTION: Epilepsy is a neurological disorder characterized by spontaneous and recurrent seizures with an estimated prevalence of 2-3 percent in the world population. Epileptic seizures are the result of paroxystic and hypersynchronous electrical activity, preferentially in cortical areas, caused by panoply of structural and neurochemical dysfunctions. Recent advances in the field have focused on the molecular mechanisms involved in the epileptogenic process. OBJECTIVES: In the present review, we describe the main genetic alterations associated to the process of epileptogenesis and discuss the new findings that are shedding light on the molecular substrates of monogenic idiopathic epilepsies (MIE) and on genetically complex epilepsies (GCE). RESULTS AND CONCLUSION: Linkage and association studies have shown that mutations in ion channel genes are the main causes of MIE and of predisposition for GCE. Moreover, mutations in genes involved in neuronal migration, glycogen metabolism and respiratory chain are associated to other syndromes involving seizures. Therefore, different gene classes contribute to the epileptic trait. The identification of epilepsy-related gene families can help us understand the molecular mechanisms of neuronal hyperexcitability and recognize markers of early diagnosis as well as new treatments for these epilepsies.

Humans , Epilepsy/genetics , Mutation , Polymorphism, Single Nucleotide/genetics , Glycogen/metabolism , Ion Channels/genetics
Indian J Exp Biol ; 2008 Jun; 46(6): 443-6
Article in English | IMSEAR | ID: sea-57074


Insulin is an important modulator of growth and metabolic function in the central nervous system. The aim of this study was to investigate the influence of swimming physical training (at 32 degrees +/- 1 degree C, 1 hr/day, 5 days/week, with an overload equivalent to 5% of the body weight, for 4 weeks) on brain insulin concentrations in alloxan induced type 1 diabetic rats. Training attenuated hyperglycemia but had no effect on insulinemia in diabetic rats. Hematocrit and blood albumin values remained without changes. Brain insulin did not change in diabetic rats. However, physical training increased the concentration in both control and diabetic rats. It is concluded that in the present experimental conditions, diabetes had no influence on brain insulin, however moderate physical training increased the hormone in both control and diabetic animals.

Animals , Blood Glucose , Brain/metabolism , Diabetes Mellitus, Experimental/metabolism , Glycogen/metabolism , Insulin/metabolism , Male , Physical Conditioning, Animal/physiology , Rats , Rats, Wistar
Rev. nutr ; 20(4): 417-429, jul.-ago. 2007. graf, tab
Article in Portuguese | LILACS | ID: lil-463147


Uma série de estudos tem sido realizada para compreensão do metabolismo de glicogênio muscular durante o exercício. Estudos clássicos apontaram uma associação entre as reservas iniciais de glicogênio muscular e o tempo de sustentação do esforço. O glicogênio muscular diminui de forma semi-logarítmica em função do tempo, mas a concentração desse substrato não chega a zero, o que sugere a participação de outros mecanismos de fadiga na interrupção do exercício prolongado. Nesse tipo de atividade, a depleção de glicogênio, primeiro, ocorre nas fibras de contração lenta, seguida pela depleção nas de contração rápida. A diminuição na taxa de utilização de glicogênio muscular está sincronicamente ligada ao aumento no metabolismo de gordura, mas o mecanismo fisiológico é pouco compreendido. Estudos recentes sugerem que uma diminuição da insulina durante o exercício limitaria o transporte de glicose pela membrana plasmática, causando um aumento no consumo de ácidos graxos. Alguns estudos têm demonstrado, também, que a própria estrutura do glicogênio muscular pode controlar a entrada de ácidos graxos livres na célula, via proteína quinase. Fisicamente, a molécula de glicogênio se apresenta de duas formas, uma com estrutura molecular menor (aproximadamente, 4,10(5) Da, Proglicogênio) e outra maior (aproximadamente, 10(7) Da, Macroglicogênio). Aparentemente, a forma Proglicogênio é metabolicamente mais ativa no exercício e a Macroglicogênio mais suscetível a aumentar com dietas de supercompensação. Maior concentração de hipoxantinas e amônia no exercício com depleção de glicogênio muscular também foi relatada, mas estudos com melhor controle da intensidade do esforço podem ajudar a elucidar essa questão.

A large number of studies have been conducted to understand muscle glycogen metabolism during exercise. Classical studies demonstrated a relationship between the pre-exercise muscle glycogen content and duration of exercise. Muscle glycogen declines in a semilogarithmic manner in function of time, but glycogen concentration does not reach zero, which suggests that other fatigue mechanisms participate in the interruption of prolonged exercise. In this type of activity, glycogen depletion occurs first in slow twitch fibers followed by fast twitch fibers. The decrease in the rate of muscle glycogen utilization is synchronized with an increased rate of fat uptake, but the physiological mechanism is not well understood. Recent studies suggest that the decline of insulin during exercise could be a limiting factor of glucose transport through the plasma membrane, which increases the uptake of fatty acids. Others studies have also demonstrated that the structure of muscle glycogen itself can regulate the cellular uptake of free fatty acids via protein kinase. Physically, the glycogen molecule has two forms, one with a smaller molecular structure (approximately 4.10(5) Da, proglycogen) and another one with a larger molecular structure (approximately 10(7) Da, macroglycogen). Apparently, the proglycogen form is more metabolically active during exercise and the macroglycogen form is more susceptible to increase with supercompensation diets. Higher concentrations of hypoxanthines and ammonia during exercise with muscle glycogen depletion have been reported, but studies that control exercise intensity better are necessary to help shed light on this issue.

Physical Exertion/physiology , Glycogen/metabolism , Hypoxanthines/metabolism , Insulin/metabolism , Muscles/metabolism