Effect of low glycogen on carbohydrate and energy metabolism in human muscle during exercise

1992 ◽  
Vol 262 (4) ◽  
pp. C975-C979 ◽  
Author(s):  
M. K. Spencer ◽  
Z. Yan ◽  
A. Katz
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Content ◽  
Tricarboxylic Acid Cycle ◽  
Work Load ◽  
Tricarboxylic Acid ◽  
Human Muscle ◽  
Acid Cycle ◽  
Before And After ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Femoris Muscle

The effect of preexercise muscle glycogen content on the metabolic responses to exercise has been investigated. Seven men cycled at a work load calculated to elicit 75% of maximal oxygen uptake [211 +/- 17 (SE) W] on two occasions: 1) to fatigue (37.2 +/- 5.3 min) and 2) at the same work load and for the same duration as the first. Biopsies were obtained from the quadriceps femoris muscle before and after exercise. Before the first experiment, muscle glycogen was lowered by exercise and diet, and before the second experiment, muscle glycogen was elevated. In the low-glycogen condition (LG), muscle glycogen decreased from 182 +/- 15 at rest to 7 +/- 4 mmol glucosyl units/kg dry wt at fatigue, while in the high-glycogen condition (HG), glycogen decreased from 725 +/- 31 at rest to 353 +/- 53 mmol glucosyl units/kg dry wt at the end of exercise. Hexose monophosphates were not increased after LG exercise but increased approximately fivefold after HG exercise. Lactate increased more during HG exercise (LG = 16 +/- 5, HG = 61 +/- 7 mmol/kg dry wt; P less than or equal to 0.001), whereas IMP increased more during LG (LG = 2.8 +/- 0.6, HG = 0.9 +/- 0.2 mmol/kg dry wt; P less than or equal to 0.05). The increases in the sum of tricarboxylic acid cycle intermediates (TCAI; citrate+malate+fumarate) and acetylcarnitine (which is in equilibrium with acetyl CoA) were significantly greater during HG exercise (P less than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate supplementation attenuates IMP accumulation in human muscle during prolonged exercise

1991 ◽  
Vol 261 (1) ◽  
pp. C71-C76 ◽  
Author(s):  
M. K. Spencer ◽  
Z. Yan ◽  
A. Katz
Keyword(s):  
Prolonged Exercise ◽  
Tricarboxylic Acid Cycle ◽  
Work Load ◽  
Tricarboxylic Acid ◽  
Human Muscle ◽  
Carbohydrate Supplementation ◽  
Large Expansion ◽  
Before And After ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Femoris Muscle

The effect of carbohydrate (CHO) ingestion on metabolic responses to exercise has been investigated. Subjects cycled at approximately 70% of maximal oxygen uptake to fatigue [135 +/- 17 (+/- SE) min] on the first occasion (control, CON) and at the same work load and duration on the second occasion but with addition of ingestion of CHO during the exercise. Biopsies were taken from the quadriceps femoris muscle before and after exercise. The sum of the hexose monophosphates (HMP), as well as lactate and alanine, in muscle was higher after CHO exercise (P less than or equal to 0.05, P less than or equal to 0.05, and P less than or equal to 0.01, respectively). Acetylcarnitine increased during exercise but was not significantly different between treatments after exercise (CON, 6.6 +/- 1.7; CHO, 10.0 +/- 1.2 mmol/kg dry wt; P = NS). The sum of the tricarboxylic acid cycle intermediates (TCAI; citrate + malate + fumarate) was increased during exercise and was higher after CHO exercise (2.34 +/- 0.32 vs. 1.68 +/- 0.17 mmol/kg dry wt; P less than or equal to 0.05). IMP was less than 0.1 mmol/kg dry wt at rest and increased to 0.77 +/- 0.26 (CON) and 0.29 +/- 0.11 mmol/kg dry wt (CHO) (P less than or equal to 0.05) during exercise. It was recently found that during prolonged exercise there is initially a rapid and large expansion of TCAI and glycogenolytic intermediates in human muscle followed by a continuous decline in TCAI and glycogenolytic intermediates [K. Sahlin, A. Katz, and S. Broberg. Am. J. Physiol. 259 (Cell Physiol. 28): C834-C841, 1990].(ABSTRACT TRUNCATED AT 250 WORDS)

Epinephrine increases tricarboxylic acid cycle intermediates in human skeletal muscle

1991 ◽  
Vol 260 (3) ◽  
pp. E436-E439 ◽  
Author(s):  
M. K. Spencer ◽  
A. Katz ◽  
I. Raz
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Adenine Nucleotides ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Quadriceps Femoris Muscle ◽  
Before And After ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Femoris Muscle

The effects of epinephrine (E) and insulin infusions on the contents of tricarboxylic acid cycle intermediates (TCAI), adenine nucleotides and their catabolites, and amino acids in skeletal muscle have been investigated. Eight men were studied on two separate occasions: 1) during 120 min of euglycemic hyperinsulinemia (UH, approximately 5 mM; 40 mU.m-2.min-1) and 2) during UH while E was infused (UHE, 0.05 microgram.kg-1.min-1). Biopsies were taken from the quadriceps femoris muscle before and after each clamp. The sum of citrate, malate, and fumarate in muscle did not change significantly during UH (P greater than 0.05) but doubled during UHE (P less than 0.001). There were no significant changes in any of the adenine nucleotides, their catabolites (including inosine monophosphate), or aspartate during UH and UHE (P greater than 0.05); nor were there any significant changes in pyruvate or alanine contents during UH (P greater than 0.05). On the other hand, there were significant increases in pyruvate and alanine contents during UHE (P less than 0.01 and 0.05, respectively), suggesting that there was increased production of 2-oxoglutarate (a TCAI) via the alanine aminotransferase (ALT) reaction. It is concluded that E infusion increases the contents of TCAI in human skeletal muscle, and it is likely that at least part of the increase is attributable to increased flux through the ALT reaction.

Tricarboxylic acid cycle intermediates in human muscle during prolonged exercise

1990 ◽  
Vol 259 (5) ◽  
pp. C834-C841 ◽  
Author(s):  
K. Sahlin ◽  
A. Katz ◽  
S. Broberg
Keyword(s):  
Prolonged Exercise ◽  
Tricarboxylic Acid Cycle ◽  
Work Load ◽  
Tricarboxylic Acid ◽  
Glycogen Depletion ◽  
Energy Deficiency ◽  
Acid Cycle ◽  
Carbohydrate Depletion ◽  
Exercise Muscle ◽  
Tricarboxylic Acid Cycle Intermediates

Seven subjects cycled to fatigue [75 +/- 5 (SE) min] at a work load corresponding to approximately 75% of their maximal oxygen uptake. Biopsies were taken from the quadriceps femoris muscle at rest and during exercise. Muscle glycogen decreased from a preexercise level of 445 +/- 33 mmol glucosyl units/kg dry wt to 50 +/- 14 at fatigue. The sum of the measured tricarboxylic acid cycle intermediates (TCAI = malate + citrate + fumarate + oxaloacetate) was 0.49 +/- 0.05 mmol/kg dry wt at rest, increased to 4.41 +/- 0.23 after 5 min of exercise, and then decreased continuously to 3.33 +/- 0.29 and to 2.83 +/- 0.27 mmol/kg dry wt after 40 min of exercise and at fatigue (P less than 0.05 vs. 5 min), respectively. The point of fatigue was characterized by an enhanced deamination of AMP (judged by increase in IMP) and reduced contents (vs. 5 min of exercise) of lactate, pyruvate, and alanine. In contrast, acetylcarnitine (reflects the availability of acetylunits) increased threefold at the onset of exercise and was maintained approximately at this level until fatigue. It is concluded that prolonged exercise to fatigue at moderate work loads results in glycogen depletion, energy deficiency (increased AMP deamination), reduced levels of three-carbon compounds and TCAI (compared with the initial phase of exercise) but in maintained levels of acetylunits. The present data indicate that carbohydrate depletion may impair aerobic energy production by reducing the level of TCAI.

scholarly journals Effects of insulin on the pattern of glucose metabolism in the perfused working and Lagendorff heart of normal and insulin-deficient rats

1969 ◽  
Vol 115 (3) ◽  
pp. 537-546 ◽  
Author(s):  
E B Chain ◽  
K. R. L. Mansford ◽  
L. H. Opie
Keyword(s):  
Glucose Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Work Load ◽  
Tricarboxylic Acid ◽  
Diaphragm Muscle ◽  
Perfusion Fluid ◽  
Acid Cycle ◽  
14Co2 Production ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Phosphorylated Sugars

1. The metabolic pattern of [U−14C]glucose in the isolated rat heart has been studied, with both retrograde aortic (Langendorff) and atrially (working) perfused preparations in the presence and absence of insulin, in normal animals, animals rendered insulin-deficient (by injection of anti-insulin serum 1hr. before excision of the heart) and animals rendered diabetic by streptozotocin injection 7 days before use. 2. Radioautochromatograms of heart extracts show that the pattern of glucose metabolism in heart muscle is more complex than in diaphragm muscle. In addition to 14CO2, glycogen, oligosaccharides, phosphorylated sugars and lactate (the main metabolites formed from [14C]glucose in diaphragm muscle), 14C label from [14C]glucose appears in heart muscle in glutamate, glutamine, aspartate and alanine, and in tricarboxylic acid-cycle intermediates. 3. By a quantitative scanning technique of two-dimensional chromatograms it was found that a mechanical work load stimulates glucose metabolism, increasing by a factor of 2–3 incorporation of 14C into all the metabolites mentioned above except lactate and phosphorylated sugars, into which 14C incorporation is in fact diminished; 14CO2 production is equally stimulated. 4. Addition of insulin to the perfusion fluid of the working heart causes increases in 14C incorporation, by a factor of about 1·5 into 14CO2, by a factor of about 3–5 into glycogen, lactate and phosphorylated sugars, by a factor of about 2–3 into glutamate and tricarboxylic acid-cycle intermediates and by a factor of about 0·5 into aspartate, whereas incorporation into alanine and glutamine is not affected. The effect of a work load on the pattern of glucose metabolism is thus different from that of insulin. 5. Increasing the concentration of glucose in the perfusion fluid from 1 to 20mm leads to changes of the pattern of glucose metabolism different from that brought about by insulin. 14CO2 production steadily increases whereas [14C]lactate and glycogen production levels off at 10mm-glucose, at values well below those reached in the presence of insulin. 6. In Langendorff hearts of animals rendered insulin-deficient by anti-insulin serum or streptozotocin, glucose uptake, formation of 14CO2 and [14C]lactate, and 14C incorporation into glycogen and oligosaccharides are decreased. In insulin-deficient working hearts, however, glucose uptake and 14CO2 production are normal, whereas incorporation of 14C into glycogen and [14C]lactate production are greatly decreased. 7. Insulin added to the perfusion fluid restores 14C incorporation from glucose into 14CO2, glycogen and lactate in the Langendorff heart from animals rendered insulin-deficient by anti-insulin serum; in hearts from streptozotocin-diabetic animals addition of insulin restores 14C incorporation into glycogen and lactate, but 14CO2 production remains about 50% below normal. 8. The bearing of these results on the problem of the mode of action of insulin is discussed.

scholarly journals Triheptanoin partially restores levels of tricarboxylic acid cycle intermediates in the mouse pilocarpine model of epilepsy

2013 ◽  
Vol 129 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Mussie G. Hadera ◽  
Olav B. Smeland ◽  
Tanya S. McDonald ◽  
Kah Ni Tan ◽  
Ursula Sonnewald ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Pilocarpine Model ◽  
Tricarboxylic Acid Cycle Intermediates

scholarly journals Metabolic phases during the development of granulation tissue

1967 ◽  
Vol 105 (1) ◽  
pp. 333-341 ◽  
Author(s):  
Kirsti Lampiaho ◽  
E. Kulonen
Keyword(s):  
Granulation Tissue ◽  
Collagen Synthesis ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Pentose Phosphate ◽  
Acid Cycle ◽  
Short Period ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Observation Period

1. The metabolism of incubated slices of sponge-induced granulation tissue, harvested 4–90 days after the implantation, was studied with special reference to the capacity of collagen synthesis and to the energy metabolism. Data are also given on the nucleic acid contents during the observation period. Three metabolic phases were evident. 2. The viability of the slices for the synthesis of collagen was studied in various conditions. Freezing and homogenization destroyed the capacity of the tissue to incorporate proline into collagen. 3. Consumption of oxygen reached the maximum at 30–40 days. There was evidence that the pentose phosphate cycle was important, especially during the phases of the proliferation and the involution. The formation of lactic acid was maximal at about 20 days. 4. The capacity to incorporate proline into collagen hydroxyproline in vitro was limited to a relatively short period at 10–30 days. 5. The synthesis of collagen was dependent on the supply of oxygen and glucose, which latter could be replaced in the incubation medium by other monosaccharides but not by the metabolites of glucose or tricarboxylic acid-cycle intermediates.

The Ethylmalonyl-CoA Pathway for Methane-based Biorefineries: A Case Study of Using Methylosinus trichosporium OB3b, an Alpha-proteobacterial Methanotroph, for Producing 2-Hydroxyisobutyric Acid and 1,3-Butanediol from Methane

2021 ◽  
Author(s):  
Dung Hoang Anh Mai ◽  
Thu Thi Nguyen ◽  
Eun Yeol Lee
Keyword(s):  
Carbon Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Methylosinus Trichosporium Ob3b ◽  
Methylosinus Trichosporium ◽  
Acid Cycle ◽  
Hydroxyisobutyric Acid ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Alpha Proteobacteria

The ethylmalonyl-CoA pathway is one of three known anaplerotic pathways that replenish tricarboxylic acid cycle intermediates and plays a major role in the carbon metabolism of many alpha-proteobacteria including Methylosinus...

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