Activation Of Anaerobic Glycolysis Research Articles

Effect of cyclic polylactates on tumor cells and tumor bearing mice.

We studied the effect of cyclic polylactates ranging in size from a degree of polymerization number of 3 to 13 on pyruvate kinase, lactic dehydrogenase, anaerobic glycolysis, growth of tumor cells and survival of tumor bearing mice. Pyruvate kinase and lactic dehydrogenase activities were both inhibited by cyclic polylactates, and the inhibition mechanism of cyclic polylactates on lactic dehydrogenase was noncompetitive. About half the anaerobic glycolytic activity of FM3A ascites tumor cells was inhibited and tumor cell growth was also effectively inhibited by cyclic polylactates. Mice, which were treated with cyclic polylactates after inoculation of FM3A ascites tumor cells lived significantly longer than mice, which were treated with vehicle or non mice.

Exercise and growth hormone: Does one affect the other?

The release of growth hormone (GH) is sensitive to many pharmacologic and physiologic stimuli, including exercise. Although the role of the increased amount of GH released during exercise is not fully understood, it most likely contributes to metabolic fuel adaptations during exercise and tissue repair after the exercise session. The GH response to exercise is altered by many factors, including sex steroid concentrations, fitness level, and the intensity of previous exercise sessions. For both endurance and resistance exercise, greater activation of anaerobic glycolysis and lactate formation increases the amount of GH released. Whether an endurance exercise session or an endurance exercise training regimen influences the total amount of GH released during a 24-hour period is not clear; this may depend on the gender of the person, the intensity of the exercise, and the duration of exercise training. The influence of a single session of resistance exercise or resistance training on 24-hour GH secretion has not been studied. Preexercise diet modulation (especially modulation of fat intake) may also influence the release of GH during endurance exercise. Studies that measure the 12- to 24-hour GH response to resistance exercise after the ingestion of various macronutrient diets have not been completed. (J Pediatr 1997;131:S75-80)

Assessment of Abnormality in Skeletal Muscle Metabolism in Patients with Chronic Lung Desease by 31P Magnetic Resonance Spectroscopy

The functional derangement of skeletal muscles which may be attributed to chronic hypoxia has been accepted as a possible mechanism of exercise impairment in patients with chronic obstructive pulmonary disease (COPD). The metabolc changes in skeletal muscle in patients with COPD are characterized by impaired oxidative phosphorylation early activation of anaerobic glycolysis and excessive lactate and hydrogen ion production with exercise. But the cause of exercise limitation in patients with chronic lung disease without hypoxia has not been known. In order to evaluate the change in the skeletal muscle metabolism as a possible cause of the exercise limitation in chronic lung disease patients without hypoxia, we compared the muscular metabolic data of seven male patients which had been derived from noninvasive 31P magnetic resonance spectroscopy(MRS) with those of five age-matched normal male control persons. 31P MRS was studied during the sustained isometric contraction of the dominant forearm flexor muscles up to the exhaustion state and the recovery period. Maximal voluntatry contraction(MVC) force of the muscle was measured before the isometric exercise, and the 30% of MVC force was constantly loaded to each patient during the isometric exercise. There were no differences of intracellular pH (pHi) and inorganic phosphate/phosphocreatine (Pi/PCr) at baseline, exhaustion state and recovery period between two groups. But pHi during the exercise was lower in patients group than the control group (p<0.05). Pi/PCr during the exercise did not show significant difference between two groups. These results suggest that the exercise limitation in chronic lung disease patients without hypoxia also could be attributed to the abnormalities in the skeletal muscle metabolism.

Inotropic stimulation by dobutamine increases left ventricular regional function at the expense of metabolism in hibernating myocardium

The mechanism by which dobutamine increases the contraction of chronically dysfunctional myocardium and its effects on metabolism are still unknown. The aim of this study was to assess regional myocardial metabolism at rest and during an intracoronary dobutamine infusion in patients with hibernating myocardium. Eleven asymptomatic patients with single proximal stenosis of the left anterior descending coronary artery and persistent left ventricular dysfunction at rest (undergoing percutaneous transluminal coronary angioplasty [PTCA]) were studied prospectively. Regional left ventricular function was assessed by two-dimensional (2D) echocardiography and regional perfusion by thallium-201 single-proton-emission computed tomography. Great cardiac vein and aortic blood samples were obtained for measurements of lactate and plasma free fatty acid (FFA) concentrations. Inotropic challenge, obtained by using intracoronary dobutamine infusion, increases regional left ventricular function. However, the arteriovenous AV lactate difference was 0.206 ± 0.070 mmol/L at rest, and it decreased to 0.018 ± 0.069 mmol/L ( p < 0.05 vs baseline) and 0.066 ± 0.068 mmol/L ( p < 0.05 vs baseline) at 4 and 10 minutes of dobutamine infusion, respectively. Thus the hibernating myocardium does not produce lactate at rest. However, when regional contraction is stimulated, dobutamine-induced inotropic challenge may cause a perfusion-contraction mismatch with an activation of anaerobic glycolysis.

31P-NMR study of skeletal muscle metabolism in patients with chronic respiratory impairment.

To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.

Effect of photic stimulation on human visual cortex lactate and phosphates using 1H and 31P magnetic resonance spectroscopy.

Previous animal and human studies showed that photic stimulation (PS) increased cerebral blood flow and glucose uptake much more than oxygen consumption, suggesting selective activation of anaerobic glycolysis. In the present studies, image-guided 1H and 31P magnetic resonance spectroscopy (MRS) was used to monitor the changes in lactate and high-energy phosphate concentrations produced by PS of visual cortex in six normal volunteers. PS initially produced a significant rise (to 250% of control, p less than 0.01) in visual cortex lactate during the first 6.4 min of PS, followed by a significant decline (p = 0.01) as PS continued. The PCr/Pi ratios decreased significantly from control values during the first 12.8 min of PS (p less than 0.05), and the pH was slightly increased. The positive P100 deflection of the visual evoked potential recorded between 100 and 172 ms after the strobe was significantly decreased from control at 12.8 min of PS (p less than 0.05). The finding that PS caused decreased PCr/Pi is consistent with the view that increased brain activity stimulated ATPase, causing a rise in ADP that shifted the creatine kinase reaction in the direction of ATP synthesis. The rise in lactate together with an increase in pH suggest that intracellular alkalosis, caused by the shift of creatine kinase, selectively stimulated glycolysis.

Effect of carnosine on the systemic hemodynamics and myocardial metabolism in rats in the early postresuscitation period

It was demonstrated in experiments on male rats that acute lethal blood loss and subsequent resuscitation after 4- and 6-min clinical death induce lipid peroxidation processes, decreased antioxidant enzyme activity, cause activation of anaerobic glycolysis in the myocardium. This metabolic heart impairment causes hemodynamic instability in postresuscitation period. 25 mg/kg of carnosine injected during resuscitation decreased functional-metabolic heart impairments and hemodynamic disarrangement as well as early postresuscitation lethality. The authors attribute positive carnosine effect to its significant antioxidant activity.

Skeletal muscle metabolism in the leg during exercise in patients with congestive heart failure

1. Using 31P nuclear magnetic resonance, it has previously been demonstrated that patients with congestive heart failure exhibit a greater than normal phosphocreatine (PCr) depletion in the working skeletal muscles of the arm. We have studied the importance of the work necessary to reach a similar PCr depletion ([PCr]/([PCr] + [Pi]) = 0.5) in calf muscle. Our results show significantly lower values for patients with congestive heart failure in both aerobic and ischaemic conditions (respectively: 0.009 +/- 0.007 vs 0.026 +/- 0.013 W/kg body weight, P less than 0.01; 0.29 +/- 0.16 vs 0.90 +/- 0.25 J/kg body weight, P less than 0.01). 2. This original model of skeletal muscle exercise facilitates a comparison of PCr recovery rate due to a similarity in the PCr depletion and intracellular pH in the two series at the start of recovery. However, the PCr recovery rate is similar after both normoxic and ischaemic exercise, i.e. respective percentages of PCr increase in the first 25 s recovery spectrum were: (a) aerobic exercise, congestive heart failure 133 +/- 18%, control series 138 +/- 18%; (b) ischaemic exercise, congestive heart failure 114 +/- 13%, control series 118 +/- 12%. The absence of a difference in PCr recovery rate and the greater PCr depletion by ischaemic work in patients with congestive heart failure suggest modifications that cannot be explained by a reduced blood flow to the muscle. 3. When comparing the two series, intracellular pH evolved similarly in normoxia and ischaemia during both work and recovery. Thus, no increase in anaerobic glycolytic activity appears when equivalent PCr depletion has occurred.

Hard contact lens-induced metabolic changes in rabbit corneas

The biochemistry of contact lens-cornea interaction is not well understood, although previous studies have suggested that corneal metabolic changes may be the underlying factor in morphological alterations. Using a rabbit model, this interaction has been examined with 31P nuclear magnetic resonance (NMR) spectroscopy, which detects signals principally from the epithelium. The examination was supplemented with electron microscopy and histochemistry. Polymethylmethacrylate lenses caused reversible changes, including activation of anaerobic glycolysis and disturbance of membrane metabolite levels. These changes were far more severe than those occurring during prolonged eye closure. There appears to be an association between cellular deterioration and loss of membrane metabolites. On the other hand, oxygen-permeable silicone lenses allowed maintenance of nearly normal metabolic patterns. These results show multifaceted corneal response to hard contact lens wear.

Relationship between the production of spirosomes and anaerobic glycolysis activity in Escherichia coli B.

The effects of culture conditions (aerobic or anaerobic) and glucose in the medium on the production of spirosomes in Escherichia coli B were studied by SDS-PAGE and electron microscopy. The Mr of the spirosome of E. coli B was estimated to be 97,000. Electron microscopy revealed that the amount of spirosomes derived from anaerobic cultures was about eightfold larger than that from aerobic cultures. In SDS-PAGE, the bands of spirosome protein derived from anaerobic cultures were more intense than those derived from aerobic cultures, either in peptone water or in Davis-Mingioli's minimal medium. With increased glucose concentration under aerobic conditions, the intensity of the band of spirosome protein was similar to that observed under anaerobic conditions in basal media. These results suggest that spirosome production by E. coli B is related to its anaerobic glycolysis activity.

Carbon-13 and proton NMR studies of post-mortem metabolism in bovine muscles

Proton and carbon-13 NMR was used to investigate post-mortem metabolism in bovine muscles at 26°C during the first 10h after slaughter. WALTZ-16 decoupling was used to eliminate the proton couplings in the 13C spectra and the ‘jump and return’ pulse sequence was used to suppress the water resonance in the 1H-NMR experiments. With carbon-13 NMR the glycogen breakdown and the lactate development could be followed. This was compared with the lactate, creatine and phosphocreatine development as measured by proton NMR. The intracellular pH was estimated from the chemical shift of the abundant dipeptide, carnosine, as measured in the 1H- and 13C-NMR spectra. These were compared with similar measurements obtained earlier using phosphorus-31 NMR. The three independently determined pH profiles were in excellent agreement with one another, as well as with results obtained with the standard iodoacetate extraction method. In the course of these studies we observed that the post-mortem metabolism in cow and heifer was slow and that it took four more hours to complete compared to bull or young bull. After 10 h the pH was 5·9 in bull and 6·1 in cow. Phosphocreatine had completely disappeared after 3·5 h in bull samples while the lactate continued to increase even after 10h. The curves obtained by carbon-13 and proton NMR for the increase in lactate during the first 10 h post mortem were very similar. Moreover, plots for the increase in the lactate level versus the intracellular pH decrease showed a linear relationship, indicating that anaerobic glycolytic activity is the main determining cause for the intracellular pH decrease. Various other parameters, such as the ratio of unsatirated to saturated fatty acid side chains and the presence of amino acids and taurine, could be measured from the in vivo carbon-13 NMR spectra. However, no gross changes occured in any of these parameters during the first 10 h post mortem.

Enhanced contractile activity of goldfish skeletal muscle related to cold acclimation

1. 1. Dorsal muscles were isolated from goldfish acclimated to 8°C and 25°C, and stimulated electrically at 5–35°C. 2. 2. Contractile activity of isolated muscle from the 8°C fish was highest at 15°C, whilst that of the 25°C fish was independent of experimental temperature. The activity was significantly increased with cold acclimation. 3. 3. Pyruvate and lactate contents of red and white muscles increased with work. 4. 4. Addition of iodoacetic acid into the incubation medium caused a decrease of lactate production and contractile activity in muscle from the 8°C fish, suggesting that the increase of the activity was partly associated with an increased activity of anaerobic glycolysis of the tissues.

Glycolytic concomitant of brain inflammation produced by goldthioglucose

In order to determine the effect of inflammation on brain glycolysis in the absence of leukocyte infiltration, [ 14C]deoxyglucose autoradiography and hematoxylin-eosin (HE) counter-staining were applied to mice at various times after the induction of chemotoxic inflammatory brain lesions by the systemic administration of goldthioglucose. Glycolysis was intensely stimulated in affected circumventricular organs, without cellular infiltration. This result is consistent with the activation of anaerobic glycolysis by inflammatory sequelae that culminate in ischemic hypoxia in the lesion sites.

Regional Flow-Metabolism Couple following Middle Cerebral Artery Occlusion in Cats

The regional flow-metabolism couple was studied during the recovery period after 1 h of left middle cerebral artery (MCA) occlusion in cats. Local CBF (LCBF) was assessed at the end of ischemia as well as at the end of 4 h of recirculation by the microsphere technique. Local CMRgl (LCMRgl) was measured at the end of the recirculation period with [14C]2-deoxyglucose. Histology was evaluated by light microscopy from coronal brain blocks adjacent to those used for the determination of LCBF and LCMRgl. When LCBF in the central and peripheral MCA territories during the recovery period was between 40 and 115% of the value in sham occlusion studies, LCMRgl was greater than the control level found in the sham studies, and was accompanied by slight histological damage. This finding suggests that anaerobic glycolysis may persist after transient ischemia in spite of the recovery of LCBF to a level that is normally greater than the threshold for the activation of anaerobic glycolysis (less than 40% of the control). Persistent anaerobic glycolysis in the reperfusion period following an ischemic insult may be a sign of early tissue damage. Some of the regions in the peripheral MCA territory with LCBF between 40 and 110% of the levels during the recovery period in the sham studies showed a mild to moderate depression in LCMRgl so that the flow-metabolism ratio remained normal. These regions did not exhibit histological damage. This possible protective mechanism of the tissue in response to ischemia is discussed from the standpoint of the relationship between flow and metabolism.

Effect of vibration on red cell metabolism.

In investigating the influence of vibrational energy on the metabolism of the erythrocyte, it was hypothesized that under conditions of normal PaO2 and SaO2 in arterial blood, vibration induced vasoconstriction would decrease local blood flow and induce hypokinetic hypoxia. This decreased blood flow and therefore decreased delivery of oxygen to the tissue would markedly lower tissue PO2 (hypokinetic hypoxia), which would influence the energetics and metabolism of the erythrocyte. The metabolism of the red blood cell (RBC) was evaluated by measuring the enzymatic activities of PFK (2.7.1.11), PGI (5.3.1.9), PK (2.7.1.40), and aldolase (4.1.3.13) from the anaerobic glycolytic cycle and D-G-6-P (1.1.1.49) from the pentose cycle. Also measured were the levels of ATP and 2,3 DPG and the in-vitro production of lactic acid. In the group of workers showing early changes (vibration angioneurosis) associated with the vibration syndrome, changes in RBC metabolism were demonstrated. Statistically significant were increases of PFK, PK and the production of lactic acid, indicating the activation of anaerobic glycolysis. Furthermore statistically significant were the increased 2,3 DPG and decreased ATP levels.

Aerobic and anaerobic degradation of glucose by the estuarine sea anemone, Diadumene leucolena

1. 1. Aerobic and anaerobic glucose degradation was investigated in intact specimens of the estuarine sea anemone, Diadumene leucolena. 2. 2. The aerobic degradation of [U- 14C]glucose resulted in radioactivity in Krebs cycle intermediates and in five amino acids (alanine, serine, glycine, aspartate and glutamate). Radioactive carbon dioxide accounted for 50% of the glucose degraded. 3. 3. Anaerobiosis resulted in decreased 14CO 2 production and enhanced labelling of succinate with no change in radioactivity in lactate. 4. 4. It is suggested that short-term anaerobiosis results in diminished oxidative metabolism in Diadumene, concomitant with an activation of anaerobic glycolysis.

Changes in biochemical and physiological indices in animals produced by the combined effect of benz [a] pyrene and phenol.

Early energy changes in lungs, liver, and kidneys during the introduction of a benz a pyrene and phenol (as the possible carcinogen activator) were studied. It was observed that 10 days after a single instance introduction of 5 mg benz a pyrene per 0.9% NaCl (60 rats), oxidative phosphorylation in the lungs and livers is disturbed in the test rats, accompanied by a reduction of adenine nucleotides in these tissues. It is assumed that at this stage, the detoxication of benz a pyrene is intensified by free oxidation systems and by the respiratory chain of mitochondria. A chronic 3-month exposure to benz a pyrene and phenol (150 rats, each 5 mg of benz a pyrene per month intratracheally and 0.4 mg/m3 of phenol round-the-clock) results in greater disturbances of the energy exchange in the lungs, liver and kidneys. Benz a pyrene and phenol, individually and in combination, inhibit oxidative phosphorylation in the lungs. This significantly decreases the content of adenine nucleotides in this tissue. Activation of anaerobic glycolysis (twofold) and of aerobic glycolysis (eightfold) does not make up for the energy insufficiency in the tissue. The effect of benz a pyrene and phenol in the liver also results in suppressing oxidative phosphorylation and in the activation of glycolysis (anaerobic 2.5 times, the aerobic 3.7 times). Changes in the bioenergy of the kidneys are not as great. Phenol in its combined effect with benz[a]pyrene intensifies the effect of the latter, as shown primarily to the greater activation of anaerobic and aerobic glycolysis in the lungs and livers of test rats. The observed disturbances as concern the weight dynamics of the animals (weight loss in test rats), vitamin metabolism (their decrease in the organs in in urine) and hemopoiesis of red blood cells (erythropenia) attest to the toxic effect of benz a pyrene phenol on the organism, which is greater in the case of the combined action of the studied agents. No changes were discerned in the morphology of white blood cells.

Changes in Biochemical and Physiological Indices in Animals Produced by the Combined Effect of Benz [a] Pyrene and Phenol

Early energy changes in lungs, liver, and kidneys during the introduction of a benz a pyrene and phenol (as the possible carcinogen activator) were studied. It was observed that 10 days after a single instance introduction of 5 mg benz a pyrene per 0.9% NaCl (60 rats), oxidative phosphorylation in the lungs and livers is disturbed in the test rats, accompanied by a reduction of adenine nucleotides in these tissues. It is assumed that at this stage, the detoxication of benz a pyrene is intensified by free oxidation systems and by the respiratory chain of mitochondria. A chronic 3-month exposure to benz a pyrene and phenol (150 rats, each 5 mg of benz a pyrene per month intratracheally and 0.4 mg/m3 of phenol round-the-clock) results in greater disturbances of the energy exchange in the lungs, liver and kidneys. Benz a pyrene and phenol, individually and in combination, inhibit oxidative phosphorylation in the lungs. This significantly decreases the content of adenine nucleotides in this tissue. Activation of anaerobic glycolysis (twofold) and of aerobic glycolysis (eightfold) does not make up for the energy insufficiency in the tissue. The effect of benz a pyrene and phenol in the liver also results in suppressing oxidative phosphorylation and in the activation of glycolysis (anaerobic 2.5 times, the aerobic 3.7 times). Changes in the bioenergy of the kidneys are not as great. Phenol in its combined effect with benz[a]pyrene intensifies the effect of the latter, as shown primarily to the greater activation of anaerobic and aerobic glycolysis in the lungs and livers of test rats. The observed disturbances as concern the weight dynamics of the animals (weight loss in test rats), vitamin metabolism (their decrease in the organs in in urine) and hemopoiesis of red blood cells (erythropenia) attest to the toxic effect of benz a pyrene phenol on the organism, which is greater in the case of the combined action of the studied agents. No changes were discerned in the morphology of white blood cells.

MECHANISMS ACTIVATING GLYCOLYSIS IN THE BRAIN IN ARTERIAL HYPOXIA

Abstract— In order to study regulatory steps responsible for the activation of anaerobic glycolysis in the brain during hypoxia, cerebral concentrations of carbohydrate substrates and organic phosphates were measured in rats after reduction of the arterial PO2 to 23‐25 mm Hg for 2, 5 and 15 min. The results demonstrated a progressive accumulation of lactate as well as of pyruvate and malate in the absence of changes in ATP, A DP, AMP, citrate and ammonia. The pattern of substrate changes obtained indicate that hypoxia is accompanied by activation of pyruvate kinase and of hexokinase, but not of phosphofructokinase. There was a progressive fall in intracellular pH and a moderate increase in the calculated cytoplasmic NADH/NAD+ ratio. The changes in pyruvate and in the NADH/NAD+ ratio may be responsible for the observed increase in the malate concentration.

Effects of externally added sodium and potassium ions on the glycolytic sequence of Saccharomyces cerevisiae

An investigation was undertaken to determine the mechanism of activation by potassium ions of anaerobi glycolysis in yeast cells. The analysis of the final intermediates of the glycolytic sequence disclosed an apparent cross-over point at the level of the pyruvate decarboxylase reaction. However, this apparent cross-over point was shown to be a consequence of the differet distributions of pyruvate in the extracellular and intracellular compartments in K+ media. During the activation of anaerobic glycolysis by K+, the observed increase in the acetaldehyde concentration does not seem to be an important regulatory factor, since a higher level of NADH was found in the presence of potassium, regardless of the higher acetaldehyde concetration. The analysis of the metabolites around the glyceraldehyde-3-phosphate dehydrogenase reaction upon the addition of K+ to yeast showed a cross-over point that could not be localized to this enzyme or to phosphoglycerate kinase. However, both ADP and ATP concentrations decreased upon the addition of K+. It is postulated that the increase of the glycolytic sequence rate by potassium ions can be explained on the basis of a decrease in ATP concentration.