Search results for "Energy Metabolism"
showing 10 items of 331 documents
New evidence for the multiplicity of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I.
2000
Determination of the number of ubiquinone- and inhibitor-binding sites in the mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a controversial question with a direct implication for elaborating a suitable model to explain the bioenergetic mechanism of this complicated enzyme. We have used combinations of both selective inhibitors and common ubiquinone-like substrates to demonstrate the multiplicity of the reaction centers in the complex I in contrast with competition studies that have suggested the existence of a unique binding site for ubiquinone. Our results provide new evidence for the existence of at least two freely exchangeable ubiquinone-binding sites with different specif…
Stable bioenergetic status despite substantial changes in blood flow and tissue oxygenation in a rat tumour.
1994
Experiments on s.c. rat tumours (DS sarcoma) were performed to determine whether chronic or acute changes in tumour perfusion necessarily lead to changes in tissue oxygenation and bioenergetic status since, as a rule, blood flow is thought to be the ultimate determinant of the tumour bioenergetic status. Based on this study, there is clear experimental evidence that growth-related or acute (following i.v. administration of tumour necrosis factor alpha) decreases in tumour blood flow are accompanied by parallel alterations in tissue oxygenation. In contrast, tumour energy status remains stable as long as flow values do not fall below 0.4-0.5 ml g-1 min-1, and provided that glucose as the mai…
Sublethal Effects of an Organophosphate Insecticide on the European Eel,Anguilla anguilla
1997
The present communication deals with the effects of fenitrothion (0.02 mg/liter) on the energy metabolism of the European eel, Anguilla anguilla, and its recovery from intoxication. Various parameters such as glycogen, lactate, proteins, and glucose levels were measured in different eel tissues after 2, 8, 12, 24, 32, 48, 56, 72, and 96 hr of fenitrothion exposure. Subsequently, the fish were allowed recovery periods of 8, 12, 24, 48, 72, 96, 144, and 192 hr in clean water, and the same parameters were evaluated. Liver glycogen content showed no significant changes during the exposure time, while blood glucose levels increased markedly. Gill, liver, and blood lactate values increased during…
Acute Metabolic Response, Energy Expenditure, and EMG Activity in Sitting and Standing
2017
Purpose While merely standing up interrupts sedentary behavior, it is important to study acute metabolic responses during single bouts of sitting and standing to understand the physiological processes affecting the health of office workers. Methods Eighteen healthy middle-age women 49.4 ± 7.9 yr old (range: 40–64) with a body mass index of 23.4 ± 2.8 kg·m−2 volunteered for this laboratory-based randomized crossover trial where they performed 2 h desk work in either sitting or standing postures after overnight fasting. Muscle activity (normalized to walking at 5 km·h−1), respiratory gas exchange, and blood samples were assessed after glucose loading (75 g). Results Compared with seated work,…
Hepatic and very low-density lipoprotein fatty acids in obese offspring of overfed dams.
2010
The combined effects of developmental programming and high-fat feeding at weaning on fatty acid metabolism of the offspring are not well known. In the present study, we aim at characterizing the influence of maternal and offspring's own diets on liver and very low-density lipoprotein (VLDL) lipids; fatty acid profiles of VLDL and liver phospholipids, triglycerides, and cholesteryl esters; and hepatic enzyme activities. Twenty obese male rats born to cafeteria diet-fed dams and 20 control rats born to control diet-fed dams were selected. At weaning, 10 rats of each group were fed control or cafeteria diet. Obese rats had a significant increase in serum glucose, insulin, leptin, VLDL apolipop…
Evidence for hypothalamic ketone bodies sensing: impact on food intake and peripheral metabolic responses in mice
2016
Monocarboxylates have been implicated in the control of energy homeostasis. Among them, the putative role of ketone bodies produced notably during high-fat diet (HFD) has not been thoroughly explored. In this study, we aimed to determine the impact of a specific rise in cerebral ketone bodies on food intake and energy homeostasis regulation. A carotid infusion of ketone bodies was performed on mice to stimulate sensitive brain areas for 6 or 12 h. At each time point, food intake and different markers of energy homeostasis were analyzed to reveal the consequences of cerebral increase in ketone body level detection. First, an increase in food intake appeared over a 12-h period of brain keton…
Hypothalamic reactive oxygen species are required for insulin-induced food intake inhibition: an NADPH oxidase-dependent mechanism
2009
1939-327X (Electronic) Journal Article Research Support, Non-U.S. Gov't; OBJECTIVE: Insulin plays an important role in the hypothalamic control of energy balance, especially by reducing food intake. Emerging data point to a pivotal role of reactive oxygen species (ROS) in energy homeostasis regulation, but their involvement in the anorexigenic effect of insulin is unknown. Furthermore, ROS signal derived from NADPH oxidase activation is required for physiological insulin effects in peripheral cells. In this study, we investigated the involvement of hypothalamic ROS and NADPH oxidase in the feeding behavior regulation by insulin. RESEARCH DESIGN AND METHODS: We first measured hypothalamic RO…
Protective action of 1,3-butanediol in cerebral ischemia. A neurologic, histologic, and metabolic study.
1987
1,3-Butanediol (BD) is converted in the body to β-hydroxybutyrate, and previous studies have shown that hyperketonemia had beneficial effects in experimental models of generalized hypoxia. The aim of this study was to determine if BD would reduce brain damage following cerebral ischemia. A transient forebrain ischemia of 30-min duration was induced by the four-vessel occlusion technique in control and BD-treated rats (25 mmol/kg, i.p.; 30 min prior to ischemia). BD treatment led to significant improvement of neurologic deficit during the 72-h recovery period and reduced neuronal damage in the striatum and cortex but not in the CA1 sector of the hippocampus. Evaluation of cerebral energy me…
Fasting prior to transient cerebral ischemia reduces delayed neuronal necrosis.
1990
A transient brain ischemia of 30-min duration was induced by the four-vessel occlusion technique in normally fed and in 48-hr-fasted rats. Evaluation of brain damage 72 hr after ischemia showed that fasting reduced neuronal necrosis in the striatum, the neocortex, and the lateral part of the CA1 sector of hippocampus. Signs of status spongiosis in the pars reticulata of the substantia nigra were seen in 75% of fed rats and in only 19% of fasted rats. The protective effect was associated with reduction in mortality and in postischemic seizure incidence. The metabolic changes induced by fasting were evaluated before and during ischemia. After 30 min of four-vessel occlusion, fasted rats showe…
Metabolomic analysis of long-term spontaneous exercise in mice suggests increased lipolysis and altered glucose metabolism when animals are at rest
2014
Exercise has been associated with several beneficial effects and is one of the major modulators of metabolism. The working muscle produces and releases substances during exercise that mediate the adaptation of the muscle but also improve the metabolic flexibility of the complete organism, leading to adjustable substrate utilization. Metabolomic studies on physical exercise are scarce and most of them have been focused on the effects of intense exercise in professional sportsmen. The aim of our study was to determine plasma metabolomic adaptations in mice after a long-term spontaneous exercise intervention study (18 mo). The metabolic changes induced by long-term spontaneous exercise were su…