Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Fructose 2,6-bisphosphate in rat skeletal muscle during contraction.

ABSTRACT: Fructose 2,6-bisphosphate and several glycolytic intermediates were measured in two rat muscles, extensor digitorum longus and gastrocnemius, which were electrically stimulated in situ. Both the duration and the frequency of stimulation were varied to obtain different rates of glycolysis. There was no relationship between fructose 2,6-bisphosphate content and the increase in tissue lactate in contracting muscle. However, in gastrocnemius stimulated at low frequencies (less than or equal to 5 Hz), there was a 2-fold increase in fructose 2,6-bisphosphate at 10s, followed by a return to basal values, whereas lactate increased only after 1 min of contraction. The concentrations of hexose 6-phosphates, fructose 1,6-bisphosphate and triose phosphates were all increased during the 3 min stimulation. During tetanus (frequencies greater than or equal to 10 Hz) fructose 2,6-bisphosphate was not increased, whereas glycolysis was maximally stimulated and resulted in an accumulation of tissue lactate, mostly from glycogen. The concentrations of hexose 6-phosphate increased continuously during the 1 min tetanus, whereas fructose 1,6-bisphosphate was increased at 10s and then decreased progressively. It therefore appears that fructose 2,6-bisphosphate does not play a role in the stimulation of glycolysis during tetanus; it may, however, be involved in the control of glycolysis when the muscles are stimulated at low frequencies for short periods of time.

SUBMITTER: Minatogawa Y

PROVIDER: S-EPMC1144266 | biostudies-other | 1984 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Changes in glucose 1,6-bisphosphate content in rat skeletal muscle during contraction.

Project description:Glucose 1,6-bisphosphate, fructose 2,6-bisphosphate, glycogen, lactate and other glycolytic metabolites were measured in rat gastrocnemius muscle, which was electrically stimulated in situ via the sciatic nerve. Both the frequency and the duration of stimulation were varied to obtain different rates of glycolysis. There was no apparent relationship between fructose 2,6-bisphosphate content and lactate accumulation in contracting muscle. In contrast, glucose 1,6-bisphosphate content increased with lactate concentration during contraction. It is suggested that the increase in glucose 1,6-bisphosphate could play a role in phosphofructokinase stimulation and in the activation of the glycolytic flux during muscle contraction.

| S-EPMC1147482 | biostudies-other

14-3-3s regulate fructose-2,6-bisphosphate levels by binding to PKB-phosphorylated cardiac fructose-2,6-bisphosphate kinase/phosphatase.

Project description:The cardiac isoform of 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase (PFK-2), regulator of the glycolysis-stimulating fructose-2,6-bisphosphate, was among human HeLa cell proteins that were eluted from a 14-3-3 affinity column using the phosphopeptide ARAApSAPA. Tryptic mass fingerprinting and phospho-specific antibodies showed that Ser466 and Ser483 of 14-3-3-affinity-purified PFK-2 were phosphorylated. 14-3-3 binding was abolished by selectively dephosphorylating Ser483, and 14-3-3 binding was restored when both Ser466 and Ser483 were phosphorylated with PKB, but not when Ser466 alone was phosphorylated by AMPK. Furthermore, the phosphopeptide RNYpS(483)VGS blocked binding of PFK-2 to 14-3-3s. These data indicate that 14-3-3s bind to phosphorylated Ser483. When HeLa cells expressing HA-tagged PFK-2 were co-transfected with active PKB or stimulated with IGF-1, HA-PFK-2 was phosphorylated and bound to 14-3-3s. The response to IGF-1 was abolished by PI 3-kinase inhibitors. In addition, IGF-1 promoted the binding of endogenous PFK-2 to 14-3-3s. When cells were transduced with penetratin-linked AARAApSAPA, we found that this reagent bound specifically to 14-3-3s, blocked the IGF-1-induced binding of HA-PFK-2 to 14-3-3s, and completely inhibited the IGF-1-induced increase in cellular fructose-2,6-bisphosphate. These findings suggest that PKB-dependent binding of 14-3-3s to phospho-Ser483 of cardiac PFK-2 mediates the stimulation of glycolysis by growth factor.

| S-EPMC165633 | biostudies-literature

Fructose 2,6-bisphosphate in rat erythrocytes. Inhibition of fructose 2,6-bisphosphate synthesis and measurement by glycerate 2,3-bisphosphate.

Project description:The concentration of fructose 2,6-bisphosphate found in freshly isolated erythrocytes was below the limit of detection (20 pmol/ml of packed cells). However, it increased to about 250 pmol/ml of cells when erythrocytes were incubated with glucose at pH 6.9, but not at pH 7.4 or 8.2. This could be explained by variations in the content of glycerate 2,3-bisphosphate, which was found to inhibit 6-phosphofructo-2-kinase, the enzyme responsible for fructose 2,6-bisphosphate synthesis. Glycerate 2,3-bisphosphate was also found to inhibit the potato enzyme (pyrophosphate:fructose-6-phosphate 1-phosphotransferase) used for the measurement of fructose 2,6-bisphosphate.

| S-EPMC1147977 | biostudies-other

Cooling of male rat skeletal muscle during endurance‐like contraction attenuates contraction‐induced PGC‐1α mRNA expression

Project description: Not available

| S-EPMC10644292 | biostudies-literature

Transient increase in glucose 1,6-bisphosphate in human skeletal muscle during isometric contraction.

Project description:Changes in glucose 1,6-bisphosphate and regulators of glucose-1,6-bisphosphate synthase and phosphatase during isometric contraction have been determined. Biopsies were obtained from the quadriceps femoris muscle before and after 20 s of contraction and at fatigue. Glucose 1,6-bisphosphate increased by 35% after 20 s of contraction (P less than 0.001) with no further change at fatigue (P greater than 0.05 versus 20 s). Pi, fructose 1,6-bisphosphate and glycerate 3-phosphate, all inhibitors of the synthase, increased significantly during the first 20 s (P less than 0.05-0.001), whereas muscle pH (decrease in which inhibits synthase) decreased continuously. The decrease in the total adenine nucleotide pool, which is stoichiometric with the increase in IMP (an activator of phosphatase), was not significant after 20 s, but was 15% at fatigue (P less than 0.001). The rapid increase in glucose 1,6-bisphosphate, despite increases in the inhibitors of synthase, suggests that the synthase was activated, possibly by the substrate glycerate 1,3-bisphosphate and/or a yet unknown activator(s). The lack of any further change in glucose 1,6-bisphosphate during the latter part of contraction may be due to concomitant activation of the synthase and phosphatase.

| S-EPMC1138452 | biostudies-other

Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.

Project description:At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle.

| S-EPMC4371155 | biostudies-other

The Effects of Caffeine on Metabolomic Responses to Muscle Contraction in Rat Skeletal Muscle.

Project description:Exercise has beneficial effects on our health by stimulating metabolic activation of skeletal muscle contraction. Caffeine is a powerful metabolic stimulant in the skeletal muscle that has ergogenic effects, including enhanced muscle power output and endurance capacity. In the present study, we aim to characterize the metabolic signatures of contracting muscles with or without caffeine stimulation using liquid chromatography-mass spectrometry and capillary electrophoresis coupled to mass spectrometry. Isolated rat epitrochlearis muscle was incubated in the presence or absence or of 3 mM caffeine for 30 min. Electrical stimulation (ES) was used to induce tetanic contractions during the final 10 min of incubation. Principal component analysis and hierarchical clustering analysis detected 184 distinct metabolites across three experimental groups-basal, ES, and ES with caffeine (ES + C). Significance Analysis of Microarray identified a total of 50 metabolites with significant changes in expression, and 23 metabolites significantly changed between the ES and ES + C groups. Changes were observed in metabolite levels of various metabolic pathways, including the pentose phosphate, nucleotide synthesis, β-oxidation, tricarboxylic acid cycle, and amino acid metabolism. In particular, D-ribose 5-phosphate, IMP, O-acetylcarnitine, butyrylcarnitine, L-leucine, L-valine, and L-aspartate levels were higher in the ES + C group than in the ES group. These metabolic alterations induced by caffeine suggest that caffeine accelerates contraction-induced metabolic activations, thereby contributing to muscle endurance performance and exercise benefits to our health.

| S-EPMC6723980 | biostudies-literature

Effects of nutritional status and acute variation in substrate supply on cardiac and skeletal-muscle fructose 2,6-bisphosphate concentrations.

Project description:We examined the long-term effects of nutritional status and the acute effects of changes in exogenous carbohydrate- and lipid-substrate supply and utilization on fructose 2,6-bisphosphate (Fru-2,6-P2) concentrations in heart, gastrocnemius and soleus. Starvation decreased Fru-2,6-P2 concentrations in all three muscles. The acute administration of insulin and glucose increased skeletal-muscle Fru-2,6-P2 in the fed, but not in the starved, state, but cardiac Fru-2,6-P2 was unchanged. Cardiac and skeletal-muscle Fru-2,6-P2 concentrations were unaffected by acute increases in fatty acid supply produced by the administration of corn oil plus heparin, or by acute decreases in fatty acid supply produced by inhibition of lipolysis. Differences in cardiac and skeletal-muscle Fru-2,6-P2 concentrations observed in response to starvation were not reversed by administration of glucose or glucose plus insulin, or by inhibition of lipolysis, even though changes in citrate (heart), acylcarnitine (heart) and glycogen (skeletal muscle) were observed. Concentrations remained low for at least 8 h after chow re-feeding, but the fed value was restored by 24 h.

| S-EPMC1148923 | biostudies-other

Fructose 2,6-bisphosphate and 6-phosphofructo-2-kinase during liver regeneration.

Project description:Glycogen and fructose 2,6-bisphosphate levels in rat liver decreased quickly after partial hepatectomy. After 7 days the glycogen level was normalized and fructose 2,6-bisphosphate concentration still remained low. The 'active' (non-phosphorylated) form of 6-phosphofructo-2-kinase varied in parallel with fructose 2,6-bisphosphate levels, whereas the 'total' activity of the enzyme decreased only after 24 h, similarly to glucokinase. The response of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase from hepatectomized rats (96 h) to sn-glycerol 3-phosphate and to cyclic AMP-dependent protein kinase was different from that of the enzyme from control animals and similar to that of the foetal isoenzyme.

| S-EPMC1131780 | biostudies-other

Hormonal control of fructose 2,6-bisphosphate concentration in isolated rat hepatocytes.

Project description:The ability of glucagon and of adrenaline to affect the concentration of fructose 2,6-bisphosphate in isolated hepatocytes was re-investigated because of important discrepancies existing in the literature. We were unable to detect a significant difference in the sensitivity of the hepatocytes with regard to the effect of glucagon to initiate the interconversion of phosphorylase, pyruvate kinase, 6-phosphofructo-2-kinase and fructose 2,6-bisphosphatase, and also to cause the disappearance of fructose 2,6-bisphosphate. In contrast, we have observed differences in the time-course of these various changes, since the interconversions of phosphorylase and of pyruvate kinase were at least twice as fast as those of 6-phosphofructo-2-kinase and of fructose 2,6-bisphosphatase. When measured in a cell-free system in the presence of MgATP, the cyclic AMP-dependent interconversion of pyruvate kinase was 5-10-fold more rapid than those of 6-phosphofructo-2-kinase and of fructose 2,6-bisphosphatase. These data indicate that 6-phosphofructo-2-kinase and fructose 2,6-bisphosphatase are relatively poor substrates for cyclic AMP-dependent protein kinase; they also support the hypothesis that the two catalytic activities belong to a single protein. Adrenaline had only a slight effect on the several parameters under investigation, except for the activation of phosphorylase. In the absence of Ca2+ ions from the incubation medium, however, adrenaline had an effect similar to that of glucagon.

| S-EPMC1152320 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data