Navegando por Palavras-chave "energy balance"
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- ItemSomente MetadadadosDistribution of energy between food-restricted dams and offspring(Karger, 1996-05-01) Luz, J.; Griggio, Mauro Antonio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Pregnant and nonpregnant rats were subjected to one of four food intake schedules: ad libitum, 20, 40 and 60% of food restriction, during 20 days, with the objective of studying the distribution of energy between food-restricted mothers and offspring. the animals were anesthetized and the conceptuses were removed and separated into male, female, and placental tissues. the rats were then killed and all carcasses were prepared for energy balance determination. A baseline group of weight-matched rats were killed in the first day of the experiment to evaluate the initial body energy. the results obtained showed that the energy balance of pregnant rats was impaired as a consequence of the food restriction imposed. the offspring from restricted mothers had lower body weight and energy content and were less in number than the ones from the control dams. It is also suggested that food restriction causes the mother to transfer similar percent energy to the offspring as in control animals which will deplete the mother energy stores more than in ad libitum fed rats.
- ItemAcesso aberto (Open Access)Efeitos do exercício crônico sobre a concentração circulante da leptina e grelina em ratos com obesidade induzida por dieta(Sociedade Brasileira de Medicina do Exercício e do Esporte, 2008-06-01) Eguchi, Ricardo [UNIFESP]; Cheik, Nadia Carla; Oyama, Lila Missae [UNIFESP]; Nascimento, Claudia Maria da Penha Oller do [UNIFESP]; Mello, Marco Tulio de [UNIFESP]; Tufik, Sergio [UNIFESP]; Dâmaso, Ana Raimunda [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Centro Universitário do TriânguloObesity is becoming one of the biggest worldwide epidemics. Therefore, knowing its etiology and mechanisms that regulate its development is of great relevance for its treatment. Thus, the aim of the present study was to evaluate the effects of obesity induced by the palatable hyperlipidic diet and of the chronic physical activity in rats, on the adiposity and the serum concentration of regulating hormones of the energy balance (leptin and ghrelin). 32 male Wistar rats were divided in four groups: Sedentary fed with chow diet (SN), sedentary fed with cafeteria diet (SC), trained fed with chow diet (TN) and trained fed with cafeteria diet (TC). The cafeteria diet led to a significant increase of central (RET) and visceral (EPI) adiposity (p<0.05). Conversely,the exercise training minimized the effect of the cafeteria diet, diminishing the central and visceral adiposity. Leptin was also increased in the groups fed with the cafeteria diet, suggesting increase of the resistance to the action of this hormone. Chronic physical activity did not hinder the development of hyperleptinemia. Reduction in the serum ghrelin concentration was observed only in the normocaloric group. Therefore,it has been concluded that the quality of diet and the quantity of adipose tissue mass behaved as important regulators of the serum concentration of leptin and ghrelin, reinforcing the importance of a suitable diet and continuous physical activity in the maintenance of body weight in the combat to the deleterious effects of obesity.
- ItemSomente MetadadadosEffects of ageing on the energy balance of food-restricted rats(Blackwell Publishing Ltd, 2004-06-01) Passadore, M. D.; Griggio, Mauro Antonio [UNIFESP]; Nunes, M. T.; Luz, J.; Universidade Federal de São Paulo (UNIFESP)Aims: Age can alter energy balance by decreasing the resting metabolic rate. Food restriction can also change energy balance by decreasing energy expenditure as a mechanism of energy conservation. We investigated the influence of food restriction on the energy balance of rats at different ages.Methods: Wistar EPM-1 female rats were used at ages of 3, 9, 15 and 21 months. At each age, two food intake schedules were provided: control (ad libitum) and food restriction (50%). Animals remained under these schedules for 30 days, and throughout this period body weight, food intake, and stool collection were controlled daily. On the 30th day, animals were killed, blood was collected and the carcasses and faeces were processed for analysis by pump calorimetry. Blood glucose, T-3, T-4 and rT(3) levels were determined.Results: Food restriction reduced energy gain and gross food efficiency of animals at different ages, but more so in older animals. Food-restricted rats also had lower energy expenditure than controls. This reduction was about 40% of the energy expenditure of control animals irrespective of age. Water content increased and fat content decreased in the carcass of food-restricted animals. Serum T-3 and T-4 levels were lower in food-restricted animals pointing out to a major role of thyroid hormones in the mechanism of energy conservation exhibited by food-restricted animals.Conclusions: the mechanism of energy conservation takes place in all restricted animals and is very important for survival and for species preservation, mainly in aged animals in which food restriction is frequently aggravated by senescence-related organic disorders.
- ItemSomente MetadadadosEffects of aging on the energy balance of pregnant rats(Karger, 1998-07-01) Luz, J.; Griggio, Mauro Antonio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In pregnant and non-pregnant female rats at various ages the energy balance was determined to study the age-induced alterations in the mother and conceptus. the animals were anesthetized and the conceptus removed and separated into male, female, and placental tissues. the animals were then killed and the carcasses prepared for energy balance determination. the results obtained showed that the older animals gained less energy in the body and had lower gross food efficiency than the younger animals. the number, energy and weight of the offspring were not affected by the mother's age. Nevertheless, due to its constant growth during life, the rat is not the best model to study age-related processes.
- ItemSomente MetadadadosEffects of ethanol on energy balance of rats and the inappropriateness of intraperitoneal injection(Elsevier B.V., 1996-11-01) Luz, J.; Griggio, Mauro Antonio [UNIFESP]; Plapler, H.; DeMeoBancher, M.; CarvalhoKosmiskas, J. V.; Universidade Federal de São Paulo (UNIFESP)Energy balance of female rats that were either injected daily with ethanol or received the alcohol by gavage was determined and the results compared with saline animals. Food intake, feces elimination, and body weight were recorded daily. After a 20-day period of treatment the animals were sacrificed and the energy content of the carcasses and feces was determined by bomb calorimetry. the results indicated that ethanol-injected animals underwent an impairment in the energy balance, with losses in body weight and body energy. Also, there was a decrease in metabolizable energy intake. the results of a group of saline rats pair-fed to alcohol-injected rats showed that the impairment of the energy balance was not only a consequence of the decreased energy intake, because the ethanol-fed animals had an energy balance that was worse than the one of the pair-fed rats, even though both had eaten the same amount of food Nevertheless, when alcohol was given by gavage, no alteration in the energy balance parameters was detected. Macroscopic observation of the abdominal cavity showed adherences in the gut of the alcohol-injected animals. It is concluded that the ethanol by itself does not alter the energy balance; however, depending on the route of administration it could indirectly impair the energy balance. Copyright (C) 1996 Elsevier Science Inc.
- ItemSomente MetadadadosEnergy balance of pregnant diabetic rats(C A B I Publishing, 2002-05-01) Yamada, Ruth [UNIFESP]; Griggio, Mauro Antonio [UNIFESP]; Luz, Jacqueline [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Pregnancy and diabetes lead to metabolic alterations in the energy balance that may not be completely independent. the objective of the present study was to look at the alterations induced by type 1 diabetes mellitus on the energy balance of pregnant rats and the offspring. Diabetes was induced by streptozotocin injection 15 d before the starting of pregnancy. the rats had their energy balance variables followed for 21 d. Protein, fat and energy content of dams was determined from samples of the carcasses. Pregnancy led to increased energy intake, energy gain and energy expenditure as well as higher gross food efficiency than non-pregnant counterparts. Diabetes increased metabolizable energy intake but not the energy gain of the animals: they had very high energy expenditure, so that diabetes blocked the improvement in gross food efficiency shown during pregnancy. Offspring from diabetic dams were born with lower body weight. Pregnant animals did not present the usual energy storage as seen by lower energy gain of diabetic dams as well as by the lower fat content in the carcasses of pregnant diabetic rats. It is concluded that diabetes impairs the energy variables usually enhanced by pregnancy alone.
- ItemSomente MetadadadosLeptin fragments induce Fos immunoreactivity in rat hypothalamus(Elsevier B.V., 2005-04-15) Oliveira, V. X.; Fazio, M. A.; Miranda, MTM; Silva, J. M. da; Bittencourt, J. C.; Elias, C. F.; Miranda, A.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Leptin presents an important role in energy balance and neuroendocrine control in mammals. in an attempt to identify regions of the leptin molecule responsible for its bioactivity, we have synthesized six peptides based on the protein three-dimensional structure. Fragments were synthesized by the solid-phase methodology, purified by reverse-phase high-performance liquid chromatography (RP-HPLC), and characterized by liquid chromatography-electrospray ionization mass spectrometry (LC/ESI-MS). They were injected intravenously and their ability to induce Fos immunoreactivity (Fos-ir) in rat hypothalamus was compared with that of the recombinant human leptin and saline. Fragment Ac-[Ser(117)]Lep(116-140)-NH2 (V) induced Fos-ir in hypothalamic nuclei that express leptin receptor long form. No similar ability was observed for the other five fragments. To investigate whether Fos-ir was induced in the same neuronal group activated by leptin, we proceeded with a dual-label immunohistochemistry for cocaine- and amphetamine-regulated transcript (CART), a neuropeptide related to leptin action in rat hypothalamus. We found that Ac-[Ser(117)]Lep(116-140)-NH2 (V) differentially activates CART neurons through the rostrocaudal extension of the arcuate nucleus. These results suggest that this fragment acts in the same group of neurons that mediate leptin response. This approach may offer the basis for the development of leptin-related compounds, having potential application in human or veterinary medicine. (C) 2004 Published by Elsevier B.V.
- ItemSomente MetadadadosParadoxical sleep deprivation and sleep recovery: Effects on the hypothalamic-pituitary-adrenal axis activity, energy balance and body composition of rats(Blackwell Publishing, 2006-04-01) Hipolide, D. C.; Suchecki, D.; Pinto, APD; Faria, E. C.; Tufik, S.; Universidade Federal de São Paulo (UNIFESP); Univ Calif RiversideNumerous studies indicate that sleep deprivation alters energy expenditure. However, this conclusion is drawn from indirect measurements. in the present study, we investigated alterations of energy expenditure, body composition, blood glucose levels, plasma insulin, adrenocorticotropic hormone (ACTH) and corticosterone levels immediately after 4 days of sleep deprivation or after 4 days of sleep recovery. Rats were sleep deprived or maintained in a control environment (groups sleep-deprived/deprivation and control/deprivation). One half of these animals were sacrificed at the end of the deprivation period and the other half was transported to metabolic cages, where they were allowed to sleep freely (groups sleep-deprived/recovery and control/recovery). At the end of the sleep recovery period, these rats were sacrificed. After sleep deprivation, sleep-deprived rats exhibited loss of body weight, augmented energy expenditure and reduced metabolic efficiency compared to control rats. These alterations were normalised during the sleep recovery period. the body composition of sleep-deprived rats was altered insofar as there was a loss of fat content and gain of protein content in the carcass compared to control rats. However, these alterations were not reversed by sleep recovery. Finally, plasma levels of insulin were reduced during the sleep deprivation period in both control and sleep deprived groups compared to the recovery period. After the deprivation period, plasma ACTH and corticosterone levels were increased in sleep-deprived rats compared to control rats, and although ACTH levels were similar between the groups after the sleep recovery period, corticosterone levels remained elevated in sleep-deprived rats after this period. By means of direct measurements of metabolism, our results showed that sleep deprivation produces increased energy expenditure and loss of fat content. Most of the alterations were reversed by sleep recovery, except for corticosterone levels and body composition.
- ItemSomente MetadadadosSerum leptin and insulin levels in lactating protein-restricted rats: implications for energy balance(Cambridge Univ Press, 2007-01-01) Ferreira, C. L. P.; Macedo, G. M.; Latorraca, M. Q.; Arantes, V. C.; Veloso, R. V.; Carneiro, E. M.; Boschero, A. C.; Nascimento, Claudia Maria da Penha Oller do [UNIFESP]; Gaiva, M. H.; Univ Fed Mato Grosso; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP)The present study analysed the effect of protein restriction on serum insulin and leptin levels and their relationship with energy balance during lactation. Four groups of rats received isocaloric diets containing 170 g protein/kg or 60 g protein/kg from pregnancy until the 14th day of lactation: control non-lactating, control lactating (both fed a control diet), low-protein non-lactating and low-protein lactating. Energy intake, body composition, energy balance. serum insulin and leptin concentrations and the relationship between these hormones and several factors related to obesity were analysed. Low-protein-intake lactating rats exhibited hypoinsulinaemia, hyperleptinaemia, hypophagia and decreased energy expenditure compared with control lactating rats. the protein level in the carcasses was lower in the low-protein lactating group than in the control lactating group, resulting in a higher fat content in the first group compared with the latter. Body fat correlated inversely with serum insulin and positively with serum leptin level. There was a significant negative correlation between serum leptin and energy intake, and a positive relationship between energy intake and serum insulin level in lactating rats and in the combined data from both groups. Energy expenditure was correlated positively with serum insulin and negatively with serum leptin in lactating rats and when data from control non-lactating and lactating rats were pooled. Lactating rats submitted to protein restriction, compared with lactating control rats, showed that maternal reserves were preserved owing to less severe negative energy balance. This metabolic adaptation was obtained, at least in part, by the hypoinsulinaemia that resulted in increased insulin sensitivity favouring enhanced fat deposition, hyperleptinaemia and hypophagia.