PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Energy Metabolism”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

[Energy metabolism and energy requirements of growing boars].

The nitrogen and energy metabolism and the energy consumption of growing boars were measured in 2 metabolic and feeding trials using 8 parallel animals each. The studies covered the 30 to 150 kg live weight range. The growth intensity of the boars was found strongly influenced by the protein level of the ration. At a crude protein level of 18% in the ration, the boars gained, on the average, 780 g per day during the fattening period under study. Energy conversion was found to decline as the protein amount went up. The energy expediture for protein deposition was estimated at 1.8 to 2.0 kcal metabolizable energy per kg deposited. The energy and feed expenditures were calculated to be 7.1 Mcal net energy--fat retention for the whole development period or 3.0 kg dry matter per kg live weight. Boars proved to have an energy requirement differing from that of barrows and gilts; equations are presented for derivation.

Animals↗
PubMed1978

Effects of ethacrynic acid and furosemide on respiration of isolated kidney tubules: the role of ion transport and the source of metabolic energy.

In order to investigate the mechanism of action of ethacrynic acid and furosemide, experiments were designed to determine whether these drugs directly inhibit active transport or energy metabolism. The effects of these diuretics on the respiration of tubule suspensions isolated from renal cortex (of rats and rabbits) and outer medulla (of rabbits) were measured. The respiration of tubules prepared from renal outer medulla was stimulated by the presence of chloride in the incubation medium, whereas the respiration of cortical tubules was unaffected by chloride. Both ethacrynic acid and furosemide produced the greatest inhibition of respiration on tubules from outer medulla suspended in chloride-containing media; this result suggests that the diuretics directly inhibit chloride transport. The source of metabolic energy for ion transport was varied by using substrates which donate electrons to the respiratory chain at different phosphorylation sites. Both ethacrynic acid and furosemide inhibit respiration supported by beta-hydroxybutyrate, but there was little or no inhibition of respiration with succinate or tetramethylphenylenediamine ascorbate. Similarly, ouabain inhibited respiration with beta-hydroxybutyrate, but not with the other substrates. Therefore, both diuretics inhibited respiration in a fashion similar to ouabain. It is concluded from both types of experiments that ethacrynic acid and furosemide may directly inhibit active chloride transport.

Animals↗
PubMed2026

Untargeted-targeted metabolomics: energy metabolism characteristics in heart failure staging and discovery of novel biomarkers.

BACKGROUND: Heart Failure represents the severe stage of various heart diseases. Its global morbidity and mortality are on the rise, making it a serious public health issue that imposes a heavy burden on patients' families and society. Currently, there are relatively few systematic studies on the changes in specific metabolites and pathways in different stages of heart failure, such as Stage A, Stage B and Stage C. AIMS: Using untargeted-targeted metabolomics to explore the metabolic characteristics of Heart Failure, and screen out serum metabolic markers with potential diagnostic and prognostic value. METHODS: This study is a cross-sectional study. A total of 210 heart failure patients from Xiyuan Hospital of China Academy of Chinese Medical Sciences were enrolled between October 2023 and October 2024. Among them, 60 patients were selected for targeted metabolomics analysis via stratified sampling. Serum samples of the patients were collected and pretreated with methanol, then metabolites were detected using untargeted and targeted LC-MS respectively. After the raw data were processed with MSDIAL, pattern recognition was performed using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). Differential metabolites with variable importance in projection (VIP)&#x2009;>&#x2009;1 and P&#x2009;<&#x2009;0.05 were screened, and relevant pathways were analyzed via enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. RESULTS: Untargeted metabolomics revealed that, compared with patients in Stages A and B, those with heart failure in Stage C had decreased serum levels of alanine, creatine, and branched-chain amino acids, along with increased levels of citric acid, fumaric acid, and malic acid. The differential metabolites were primarily enriched in pathways including the citric acid cycle, central carbon metabolism, and amino acid metabolism, indicating that energy metabolism plays a crucial role in the occurrence and progression of HF. Targeted metabolomics validated the findings from untargeted metabolomics: compared with Stage A, the level of phosphoenolpyruvate in Stage B was reduced; and in comparison with patients in Stage A or B, patients in Stage C showed decreased serum levels of multiple energy metabolites (e.g., glucose-6-phosphate, fructose-6-phosphate, 3-phosphoglyceric acid, AMP, ADP and ATP) as well as increased levels of malic acid, which is consistent with the characteristics of the "hypermetabolism-energy starvation" paradox. CONCLUSION: Stage C of heart failure is characterized by energy metabolism collapse (decreased ATP and TCA compensation), and differential metabolites (such as malic acid) may serve as potential candidate biomarkers pending longitudinal validation.

Humans↗
PubMed1979

Dispersal and reformation of acetylcholine receptor clusters of cultured rat myotubes treated with inhibitors of energy metabolism.

The effects of energy metabolism inhibitors on the distribution of acetylcholine receptors (AChRs) in the surface membranes of non-innervated, cultured rat myotubes were studied by visualizing the AChRs with monotetramethylrhodamine-alpha-bungarotoxin. Incubation of myotubes with inhibitors of energy metabolism causes a large decrease in the fraction of myotubes displaying clusters of AChR. This decrease is reversible, and is dependent on temperature, the concentration of inhibitor, and the duration of treatment. Cluster dispersal is probably not the result of secondary effects on Ca++ or cyclic nucleotide metabolism, membrane potential, cytoskeletal elements, or protein synthesis. Sequential observations of identified cells treated with sodium azide showed that clusters appear to disperse by movements of receptors within the sarcolemma without accompanying changes in cell shape. AChR clusters dispersed by pretreating cells with sodium azide rapidly reform upon removal of the inhibitor. Reclustering involves the formation of small aggregates of AChR, which act as foci for further aggregation and which appear to be precursors of large AChR clusters. Small AChR aggregates also appear to be precursors of clusters which form on myotubes never exposed to azide. Reclustering after azide treatment does not necessarily occur at the same sites occupied by clusters before dispersal, nor does it employ only receptors which had previously been in clusters. Cluster reformation can be blocked by cycloheximide, colchicine, and drugs which alter the intracellular cation composition.

Acetylcholine↗
PubMed2026

Acute and chronic effects of mixed nuts on energy metabolism in women at cardiometabolic risk: a randomized clinical trial.

BACKGROUND AND AIMS: The effect of consuming a mix of Brazilian nuts on energy metabolism has not been explored. Thus, the present study aimed to evaluate the effects of acute and chronic consumption of mixed nuts on markers of energy metabolism in women with overweight/obesity. METHODS AND RESULTS: This is a randomized, controlled, and parallel clinical trial with adult women. In an acute study, participants received a beverage containing mixed nuts (30&#xa0;g of cashew nuts&#xa0;+&#xa0;15&#xa0;g of Brazil nuts) or a control beverage, and energy metabolism markers were assessed for up to 3&#xa0;h postprandially. For the chronic study, participants received 45&#xa0;g of a mix of nuts/day and a -500kcal energy-restricted diet (MNG) or only a -500kcal energy-restricted diet free of nuts (CTG) for 8 weeks, and energy metabolism was assessed before and after the intervention period. In the postprandial period, fat oxidation was higher in the MNG than in the CTG (piAUC: 47.53&#xa0;&#xb1;&#xa0;5.78&#xa0;mg/min vs. 27.93&#xa0;&#xb1;&#xa0;6.98&#xa0;mg/min; p&#xa0;=&#xa0;0.048). After 8 weeks of the intervention, fasting fat oxidation increased in the MNG (+16.0&#xa0;&#xb1;&#xa0;7.0&#xa0;mg/min) and decreased in the CTG (-5.0&#xa0;&#xb1;&#xa0;6.0&#xa0;mg/min), with no significant difference between groups. Other acute and chronic markers also showed no significant changes between groups. CONCLUSION: The acute consumption of mixed nuts increased postprandial fat oxidation, whereas chronic intake within an energy-restricted diet did not affect energy metabolism markers in women at cardiometabolic risk. REGISTRATION NUMBER FOR BRAZILIAN REGISTRY OF CLINICAL TRIALS: RBR-3ntxrm.

Humans↗
PubMed1979

Effects of reduced cerebral blood flow upon EEG pattern, cerebral extracellular potassium, and energy metabolism in the rat cortex during bicuculline-induced seizures.

Progressive cerebral ischemia was induced by blood pressure (BP) reduction in rats during status epilepticus, and the sequence of cerebral functional (EEG, extracellular K+ activity) and metabolic (levels of high energy phosphates, glucose, glucose-6-phosphate, lactate, pyruvate, alpha-ketoglutarate) changes were determined. Very moderate reductions of BP were accompanied by tissue lactate accumulation and a decrease of the rate of re-uptake of K+ extruded during discharges. These changes were pronounced at BP about 50 mm Hg, when also the energy state showed some deterioration, and the EEG activity changed from one of bursts and suppressions into single spikes. At BP about 30 mm Hg EEG activity was abolished, but not until a slightly lower BP level was there a severe energy depletion and a massive K+ release, indicating generalized membrane depolarization. The results show an increased susceptibility to ischemia during seizures with changes of membrane pump function, and energy metabolism appearing at moderate reductions of BP. Concomitant decrease of seizure activity delayed to some extent the development of massive energy failure and membrane depolarization.

Animals↗
PubMed1976

Adenine nucleotide metabolism of blood platelets. IX. Time course of secretion and changes in energy metabolism in thrombin-treated platelets.

Changes in the energy metabolism of washed human platelets were compared with the kinetics of secretion induced by thrombin (5 units/ml). A 50% decrease in the level of metabolic ATP (3H-labelled), which was essentially complete in 30s, was matched in rate by adenine nucleotide secretion from storage in dense granules. Incubation of platelets with antimycin before thrombin addition increased the rate of fall in metabolic ATP, but did not affect the rate of adenine nucleotide secretion. beta-N-Acetylglucosaminidase secretion, which was slower than adenine nucleotide secretion in control platelets, was noticeably inhibited by antimycin, confirming previous reports that different regulatory mechanisms exist for dense and alpha-granule secretion. The rates of rephosphorylation of metabolic ADP to ATP via glycolysis and oxidative phosphorylation were estimated by measuring lactate production and O2 consumption in resting and thrombin-stimulated platelets and compared to the level of metabolic ATP (9-10 nmol/mg of platelet protein in the resting state). The rate of ATP production was stimulated at least two fold from 12 nmol to 24 nmol/min/mg within seconds of thrombin addition. This increased rate was maintained over the observed period of 5 min although the level of metabolic ATP had decreased to 4-5 nmol/mg within 30 s; the turnover of the remaining metabolic ATP thus increased four fold over the resting state although the actual stimulation of energy production was only two fold.

Adenosine Diphosphate↗
PubMed1979

Intracellular oxygen tension and energy metabolism in the cat brain cortex during haemorrhagic shock.

The changes in intracellular oxygen tension and energy metabolism of the cat brain cortex were studied by surface fluororeflectometry during haemorrhagic shock. The results may be summarized as follows. (a) Intracellular oxygen tension, i.e. the maximum cortical NAD reduction obtained during nitrogen gas inhalation decreased gradually during the hypovolaemic phase of shock and finally, the brain cortex became ischaemic. (b) Partial uncoupling of the cerebrocortical mitochondrial respiration and oxidative phosphorylation appeared in the very early period of bleeding, as indicated by the overshot of the cortical NAD/NADH redox state towards oxidation subsequent to the cessation of nitrogen gas inhalation. Partial uncoupling of mitochondrial respiration and oxidative phosphorylation became more pronounced during the later phases of bleeding, finally, the mitochondrial electron transport stopped. In line with these changes the frequency and the amplitude of ECoG decreased gradually and markedly during the hypovolaemic phase of shock. (c) Microcirculation and energy metabolism of the cat brain cortex were severely and irreversibly damaged during the hypovolaemic phase of shock. This was clearly shown by the fact that in the majority of experiments the nitrogen anoxia after reinfusion failed to bring about changes in the cortical NAD/NADH redox state and the ECoG changes occurred during bleeding did not improve after reinfusion. It is concluded that the early disturbances of cerebrocortical energy metabolism play an important role in the development of neural and vascular lesions of the brain that occur during haemorrhagic shock.

Action Potentials↗
PubMedDate not supplied

Characteristics of energy metabolism in specialized muscle of bovine heart.

Characterization of the energy metabolism pattern of the specialized heart muscle of bovine heart was studied in comparison with that of the ordinary heart muscle. Mitochondrial oxygen consumption of the specialized heart muscle was significantly lower than that of the ordinary heart muscle with succinate as the substrate. On the other hand, there was no significant difference in oxygen consumption between both heart muscles with glutamate + malate as the substrates. The activity levels of succinate dehydrogenase and lactate dehydrogenase were much lower than those of the ordinary heart muscle. The isozyme pattern of LDH of the specialized heart muscle consisted of one major component of LDH-1 (H4) and that of the ordinary heart muscle consisted of two major components of LDH-1 (H4) and LDH-2 (H3M). The ratio of NADH to NAD of the specialized heart muscle was remarkably lower than that of the ordinary heart muscle. These results indicate that the specialized heart muscle depends not only upon anaerobic metabolism but also upon aerobic metabolism for its energy supply.

Animals↗
PubMed1975

Energy metabolism of isolated rat thymus cells.

The energy metabolism of rat thymus cells has been investigated using preparations of isolated cells obtained by mechanical treatment of whole organs. The addition of glycolytic substrates such as glucose, pyruvate and lactate stimulates the endogenous respiration of these cells by 50%. On the other hand, succinate, glutamate and malate do not produce any effect. Oligomycin (10 mug/ml) inhibits both endogenous and glucose stimulated respiration by about 40%; 2, 4-DNP (50 muM) increases by 100% glucose induced respiration. The results obtained by using mitochondrial and glycolytic inhibitors as well as aminoxyacetic acid (AOA) and following pyridine nucleotides redox changes, support the idea that in thymus cells glucose is able to induce a great enhancement of O2 consumption both by raising the level of endogenous pyruvate and feeding the mitochondrial respiratory chain with cytosolic reducing equivalents, through an active malate-aspartate shuttle. Thymus cells exhibit a high Pasteur effect (74%). Both AOA and 2,4 DNP are able to stimulate aerobic lactate accumulation by 200% and 100% respectively, indicating that either the redox or phosphate potential do influence the rate of aerobic glycolysis in isolated thymus cells. Similar experiments are also reported on other cells with well known biochemical characteristics.

Animals↗
PubMed1979

[Energy metabolism of the brain in children (author's transl)].

Oxygen consumption of the human brain is of the order of 3,5 ml./minute. Since the brain of a 70 Kg. man has a weight of 1,400 g., its total oxygen consumption is close to 50 ml./minute. Thus, whereas the brain weight accounts only for about 2 percent of the body weight its oxygen consumption accounts for some 20 percent of the resting energy metabolism (BMR) of the body. Measurements in animals of different size indicates that the oxygen consumption of the mammalian brain, per unit of weight, is practically independent of body size. Accordingly, the above figure can be used to make an estimate of the fraction of BMR accounted for by the energy metabolism of the brain, in different species. The proportion of brain weight to total body weight changes during the period of growth. The brain of a new-born baby represents some 10 to 11 percent of the total body weight. Therefore, in spite of the fact that the BMR/Kg. is higher in the infant, the fraction of BMR accounted for by the metabolism of the brain, is expected to be higher in the infant and child than in the adult. The calculations presented in this paper show that the energy metabolism of the brain may account for about 50 percent of the BMR in the new-born. As indicated by our calculations the proportion of BMR accounted for by the energy metabolism of the brain decreases with age, but it still accounts for about 30 percent of the BMR at age 12 years. Our calculations also show that much of the decrease of BMR/Kg. that takes place during infancy and childhood, is due to the decrease in the proportion of brain weight to total body weight. Undernourished children tend to have higher brain weight, relative to total body weight, than eutrophic children. It has been proposed, that this fact could explain the high BMR observed in malnourished children during nutritional rehabilitation.

Adult↗
PubMed1977

Fast axonal transport: effect of antimitotic drugs and inhibitors of energy metabolism on the rate and amount of transported protein in frog sciatic nerves.

Mitosis inhibitors, drugs affecting the energy metabolism, heavy water, and ouabain were used to partially inhibit fast axonal transport in frog sciatic nerves. Effects on the rate and on the amount of pulse labeled protein could be separated. The pulse of labeled protein, released after a cold-block, rapidly reached a maximum height which indicated that the transport system was saturated in the nerve segment occupied by the pulse. Both the rate and the amount were reduced by the mitosis inhibitors colchicine, vinblastine, and griseofulvin. Colchicine had a differential effect and reduced the rate of material migrating in the advancing front of the pulse less than the rate of that moving in the peak. Preincubation at low temperature potentiated the effects of colchicine. Two inhibitors of energy metabolism, NaCN and IAA, reduced the amount of labeled material in the pulse. The slope of the pulse was markedly reduced and multiple peaks appeared. The distance covered by the migrating pulse was largely unaffected, but some retardation of late components might have occurred. In contrast, 2.4-DNP reduced the rate without any effects on the amount of migrating material. Heavy water uniformly reduced the rate of the migrating pulse, whereas the main effect of ouabain was a diminished amount and multiple peaks as with NaCN and IAA. All drugs were tested for their effects on the electrical activity of sciatic nerves. The compound action potential was not affected by the mitosis inhibitors and heavy water, but was depressed by the inhibitors of energy metabolism and abolished by ouabain. The results indicate that the effects of various transport inhibitory drugs can be differentiated if both the rate and the amount are considered.

Action Potentials↗
PubMed2026

Transcriptomic responses of Porphyrophora sophorae larvae during licorice root colonization reveal coordinated remodeling of translation, mitochondrial energy metabolism and defense-related genes.

BACKGROUND: Porphyrophora sophorae is a subterranean piercing-sucking scale insect that damages licorice (Glycyrrhiza uralensis) roots, but the molecular responses associated with larval root colonization remain insufficiently defined. METHODS: We compared non-parasitic larvae (NP) and root-colonizing larvae (RC) using six RNA-seq libraries, de novo transcriptome assembly, DESeq2-based differential expression analysis, GO/KEGG enrichment, annotation-based candidate gene screening, and RT-qPCR validation of selected genes. RESULTS: Sequencing yielded 260.91 million clean reads, and de novo assembly produced 60,794 non-redundant transcripts. DESeq2 identified 703 FDR-significant DEGs, including 49 upregulated and 654 downregulated genes in RC larvae. Upregulated genes were mainly associated with translation- and ribosome-related processes, whereas downregulated genes were enriched in mitochondrial, oxidation-reduction, energy metabolism, and oxidative phosphorylation-related functions. Annotation-based screening identified 75 FDR-significant candidate genes associated with chemosensation, defense-related responses, and energy metabolism, with mitochondrial energy metabolism-related genes forming the largest module. RT-qPCR validation based on the raw Ct data showed concordant expression directions for ten selected transcript targets. CONCLUSIONS: Root colonization in P. sophorae larvae was associated with coordinated transcriptional remodeling involving selective activation of translation-related processes, adjustment of mitochondrial energy metabolism, and changes in defense-related gene expression. These results provide candidate molecular targets for future functional studies of host contact, feeding establishment, and physiological adjustment in this subterranean scale insect.

Animals↗
PubMed1978

Respiration and carbohydrate energy metabolism of the lung-dwelling parasite Rhabdias bufonis (Nematoda: Rhabdiasoidea).

An investigation of the carbohydrate energy metabolism of Rhabdias bufonis, the lung-dwelling nematode parasite of the African toad, Bufo regularis, indicates that the nematode stores very little glycogen (0.137 +/- 0.003% on a fresh weight basis) but does utilize oxygen in vitro. The intracellular distribution and high levels of activity observed for the enzymes phosphoenolpyruvate carboxykinase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, malic enzyme and fumarate reductase suggest two alternative pathways of carbohydrate energy metabolism.

Animals↗