INFLUENCE OF EXPERIMENTAL HYPERTHYROIDISM ON SKELETAL MUSCLE METABOLISM IN THE RAT

1977 ◽  
Vol 85 (1) ◽  
pp. 71-83 ◽  
Author(s):  
C. van Hardeveld ◽  
A. A. H. Kassenaar
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Dose Range ◽  
Nervous Activity ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Glucose Consumption ◽  
Daily Injection ◽  
Limb Perfusion ◽  
Energy Consuming

ABSTRACT In this study hind-limb perfusion was used to investigate the influence of thyroid hormones on some metabolic parameters in the skeletal muscle of the rat. Daily injection of 20 μg L-thyroxine (T4) per 100 g b. w. for a week caused a 25 % increase in oxygen consumption. Further enlargement of the T4 dose had little additive effect. In the dose range 20–80 μg T4/100 g b. w., no important changes occurred in lactate production or glucose consumption. Only at the highest T4 dose did the glucose consumption increase significantly. The most profound effect of T4 was on lipolysis. A daily dose of 20 μg T4/100 g b. w. gave a doubling of glycerol production rate, the maximum occurring at a dose of 40 μg T4/100 g b. w Inactivation of the nervous system was without influence on the T4-induced increase in oxygen consumption. However, the T4-induced elevation of lipolysis disappeared after abolition of the nervous activity. This raises the possibility that the T4 effect on lipolysis in skeletal muscle is a potentiation of catecholamine effects. The T4-induced oxygen consumption increase might be dependent not on the lipolytic process but rather on other energy-consuming cell processes.

EFFECTS OF EXPERIMENTAL HYPOTHYROIDISM ON SKELETAL MUSCLE METABOLISM IN THE RAT

1978 ◽  
Vol 87 (1) ◽  
pp. 114-124 ◽  
Author(s):  
C. van Hardeveld ◽  
A. A. H. Kassenaar
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Initial Level ◽  
Control Level ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Glucose Consumption ◽  
Glycerol Production ◽  
Base Level ◽  
Limb Perfusion

ABSTRACT Hind-limb perfusion was used to study the effect of thyroidectomy on some metabolic parameters in the skeletal muscle of the rat. A week after thyroidectomy obtained by one dose of 3/4 mCi 131I, neither T4 nor T3 was detected in the blood. Lactate production and glycerol production were already decreased a week after the treatment and reached a base level at two weeks. At that time, the oxygen consumption was significantly lower (70 % of initial level) than in the control animals and decreased further in the third week to nearly 50 % of the control level. Glucose consumption and alanine release were decreased three weeks after thyroidectomy. One dose of T3 (10 μg/100 g b. w.), administered to animals two weeks after the injection of 131I, restored the oxygen consumption, lactate production, and glycerol production to normal levels in 24 h. After 48 h, the glucose consumption was normal. Glycerol production was already significantly increased 6 h after T3 injection in animals one week after thyroidectomy, and in another group of animals two weeks after thyroidectomy. Apparently the diminished oxygen consumption in the latter group does not retard the lipolytic response to T3. No direct relationship could be found between the activity of lipolytic process and the thyroid hormone controlled oxygen consumption.

Force development and metabolism in skeletal muscle of euthyroid and hypothyroid rats

1981 ◽  
Vol 97 (2) ◽  
pp. 221-225 ◽  
Author(s):  
M. E. Everts ◽  
C. van Hardeveld ◽  
H. E. D. J. Ter Keurs ◽  
A. A. H. Kassenaar
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Muscle Metabolism ◽  
Glucose Consumption ◽  
Triceps Surae ◽  
Active Force ◽  
Muscle Preparation ◽  
Force Development ◽  
Contraction Process ◽  
Triceps Surae Muscles

Abstract. The effects of thyroid hormone depletion on skeletal muscle metabolism in relation to force development were studied. For this purpose, the triceps surae muscles were perfused and stimulated at 5 Hz. The basal oxygen consumption of the skeletal muscle preparation was 50% lower in hypothyroid rats as compared with euthyroid rats. The results show that: 1. Active force development was the same in euthyroid and hypothyroid rats during 30 min of stimulation. 2. The increase in oxygen consumption during contraction was twice as high in the euthyroid group compared with the hypothyroid group. 3. Lactate release and glucose consumption were considerably higher in the euthyroid group than in the hypothyroid group during the last 15 min of stimulation. The data show that force development is not impaired in hypothyroid rats but, on the contrary, indicate that the contraction process proceeds more economically in hypothyroid rats than in euthyroid rats.

LEUCOCYTE METABOLISM IN PREGNANCY

1960 ◽  
Vol XXXV (IV) ◽  
pp. 575-584 ◽  
Author(s):  
C. Borel ◽  
J. Frei ◽  
A. Vannotti
Keyword(s):  
Alkaline Phosphatase ◽  
Oxygen Consumption ◽  
Pregnant Women ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Lactate Production ◽  
Glucose Consumption ◽  
In Pregnancy

ABSTRACT Enzymatic studies, on leucocytes of pregnant women, show an increase of the alkaline phosphatase activity and a decrease of the glucose consumption and lactate production, as well as of proteolysis. The oxygen consumption, with succinate as substrate, does not vary.

scholarly journals Regulation of glycogen phosphorylase and PDH during exercise in human skeletal muscle during hypoxia

2000 ◽  
Vol 278 (3) ◽  
pp. E522-E534 ◽  
Author(s):  
Michelle L. Parolin ◽  
Lawrence L. Spriet ◽  
Eric Hultman ◽  
Melanie G. Hollidge-Horvat ◽  
Norman L. Jones ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glycogen Phosphorylase ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Lactate Accumulation ◽  
Pyruvate Oxidation ◽  
Reduced Rate ◽  
Rate Limiting ◽  
Muscle Biopsies ◽  
Elevated Lactate

The present study examined the acute effects of hypoxia on the regulation of skeletal muscle metabolism at rest and during 15 min of submaximal exercise. Subjects exercised on two occasions for 15 min at 55% of their normoxic maximal oxygen uptake while breathing 11% O2 (hypoxia) or room air (normoxia). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to hypoxia. In the 1st min of exercise, glycogenolysis was significantly greater in hypoxia compared with normoxia. This small difference in glycogenolysis was associated with a tendency toward a greater concentration of substrate, free Pi, in hypoxia compared with normoxia. Pyruvate dehydrogenase activity (PDHa) was lower in hypoxia at 1 min compared with normoxia, resulting in a reduced rate of pyruvate oxidation and a greater lactate accumulation. During the last 14 min of exercise, glycogenolysis was greater in hypoxia despite a lower mole fraction of phosphorylase a. The greater glycogenolytic rate was maintained posttransformationally through significantly higher free [AMP] and [Pi]. At the end of exercise, PDHawas greater in hypoxia compared with normoxia, contributing to a greater rate of pyruvate oxidation. Because of the higher glycogenolytic rate in hypoxia, the rate of pyruvate production continued to exceed the rate of pyruvate oxidation, resulting in significant lactate accumulation in hypoxia compared with no further lactate accumulation in normoxia. Hence, the elevated lactate production associated with hypoxia at the same absolute workload could in part be explained by the effects of hypoxia on the activities of the rate-limiting enzymes, phosphorylase and PDH, which regulate the rates of pyruvate production and pyruvate oxidation, respectively.

Effects of substrate and hypoxia on smooth muscle metabolism and contraction

1989 ◽  
Vol 256 (4) ◽  
pp. C719-C727 ◽  
Author(s):  
I. R. Wendt
Keyword(s):  
Smooth Muscle ◽  
Oxygen Consumption ◽  
Urinary Bladder ◽  
Heat Production ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Sufficient Energy ◽  
Rabbit Urinary Bladder

Suprabasal heat production, oxygen consumption, and lactate production were measured, together with force, in 30-s isometric contractions of longitudinal smooth muscle from rabbit urinary bladder at 27 degrees C. Either glucose or pyruvate was provided as exogenous substrate. Under aerobic conditions with glucose as substrate, force averaged 95 mN/mm2 and heat production 121 mJ/g. Oxygen consumption (0.18 mumol/g) could account for only two-thirds of the total energy expenditure represented as heat production. The remaining one-third was accounted for by aerobic lactate production (0.36 mumol/g). When pyruvate replaced glucose as substrate, both the force developed and the total heat liberated were unchanged. Oxygen consumption, however, increased by approximately 40% (to 0.25 mumol/g) and was able to fully account for the measured heat production. The frequency of spontaneous contractions under aerobic conditions was always reduced in the presence of pyruvate. Under anaerobic conditions force was essentially unaltered, and heat production was only slightly reduced (101 mJ/g) with glucose present. Lactate production increased threefold over that under aerobic conditions. With pyruvate as substrate both force and heat production declined markedly (to less than 5% of the aerobic values). The results indicate that under aerobic conditions and with glucose as substrate, smooth muscle of rabbit urinary bladder generates about one-third of its suprabasal energy requirements through glycolysis and that glycolysis can be further accelerated under anaerobic conditions to provide sufficient energy to sustain contraction. If pyruvate replaces glucose as substrate, the metabolism shifts to being virtually all oxidative, and contraction can no longer be sustained in the absence of oxygen.

scholarly journals IMP2 Increases Mouse Skeletal Muscle Mass and Voluntary Activity by Enhancing Autocrine Insulin-Like Growth Factor 2 Production and Optimizing Muscle Metabolism

2019 ◽  
Vol 39 (7) ◽  
Author(s):  
Laura Regué ◽  
Fei Ji ◽  
Daniel Flicker ◽  
Dana Kramer ◽  
William Pierce ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Growth Factor ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Wheel Running ◽  
Muscle Metabolism ◽  
Insulin Like Growth Factor ◽  
Voluntary Activity ◽  
Mouse Muscle

ABSTRACT Insulin-like growth factor 2 (IGF2) mRNA binding protein 2 (IMP2) was selectively deleted from adult mouse muscle; two phenotypes were observed: decreased accrual of skeletal muscle mass after weaning and reduced wheel-running activity but normal forced treadmill performance. Reduced wheel running occurs when mice are fed a high-fat diet but is normalized when mice consume standard chow. The two phenotypes are due to altered output from different IMP2 client mRNAs. The reduced fiber size of IMP2-deficient muscle is attributable, in part, to diminished autocrine Igf2 production; basal tyrosine phosphorylation of the insulin and IGF1 receptors is diminished, and Akt1 activation is selectively reduced. Gsk3α is disinhibited, and S536-phosphorylated ε subunit of eukaryotic initiation factor 2B [eIF2Bε(S536)] is hyperphosphorylated. Protein synthesis is reduced despite unaltered mTOR complex 1 activity. The diet-dependent reduction in voluntary exercise is likely due to altered muscle metabolism, as contractile function is normal. IMP2-deficient muscle exhibits reduced fatty acid oxidation, due to a reduced abundance of mRNA of peroxisome proliferator-activated receptor α (PPARα), an IMP2 client, and PPARα protein. IMP2-deficient muscle fibers treated with a mitochondrial uncoupler to increase electron flux, as occurs with exercise, exhibit reduced oxygen consumption from fatty acids, with higher oxygen consumption from glucose. The greater dependence on muscle glucose metabolism during increased oxygen demand may promote central fatigue and thereby diminish voluntary activity.

Hydrogen ion concentration and oxygen uptake in an isolated canine hindlimb

1976 ◽  
Vol 40 (1) ◽  
pp. 1-5 ◽  
Author(s):  
A. H. Harken
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Lactate Production ◽  
Hydrogen Ion ◽  
Arterial Oxygen ◽  
Hydrogen Ion Concentration ◽  
Membrane Lung ◽  
Arterial Blood ◽  
The Mean

Oxygen utilization (VO2) and lactate production by an isolated perfused canine hindlimb was evaluated at various hydrogen ion concentrations. A membrane lung perfusion system was established such that blood flow and temperature could be fixed at normal levels. Oxygen, nitrogen, and carbon dioxide (CO2) gas flows to the membrane lung were independently regulated to provide a fixed arterial oxygen content (CaO2). By changing CO2 flow, the pH of the arterial blood was varied between 6.9 and 7.6 at 10-min intervals. The mean O2 delivery (CaO2 X blood flow) was between 16.3 ML O2/min and 20.5 ml O2/min. Standard error of the mean in each dog, however, was less than 0.4 ml O2/min. VO2 was linearly related to the pH of the perfusing blood: VO2% = 100.1 pH - 643 (r = 0.866). Oxygen consumption was inversely related to PCO2: VO2% = -0.62 PCO2 + 124, but the correlation was less good (r = 0.729). Lactate production was linearly related to the pH of the perfusing blood (above a pH of 7.4): lactate produced = 22.5 pH - 162.5 (r = 0.75). At a pH below 7.4, lactate was not produced. Oxygen consumption of skeletal muscle appears critically dependent on extracellular fluid pH. A change in pH of 0.1 alters VO2 almost exactly 10%. Alkalosis is a potent stimulus to lactic acid production by skeletal muscle.

scholarly journals Tadalafil alters energy metabolism in C2C12 skeletal muscle cells.

2011 ◽  
Vol 58 (2) ◽  
Author(s):  
Stefania Sabatini ◽  
Paolo Sgrò ◽  
Guglielmo Duranti ◽  
Roberta Ceci ◽  
Luigi Di Luigi
Keyword(s):  
Skeletal Muscle ◽  
Energy Metabolism ◽  
Energy Homeostasis ◽  
Citrate Synthase ◽  
Lactate Production ◽  
Glucose Consumption ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Cell Functions ◽  
C2c12 Skeletal Muscle Cells

Phosphodiesterases (PDEs) are a family of enzymes that hydrolyze cyclic nucleotides, thereby modulating cell functions. Three highly selective PDE5 inhibitors (PDE5i), sildenafil, vardenafil and tadalafil, have been developed for treatment of erectile dysfunction (ED). Experimental evidence showed that chronic treatment with sildenafil PDE5i in a mouse model of diet-induced obesity and insulin resistance improved insulin action and decreased circulating fatty acid levels. It has recently been shown that healthy athletes use PDE5i as performance enhancers, hence in the present study we investigated whether the long-lasting PDE5i tadalafil influences energy metabolism in C2C12 skeletal muscle cells by evaluating lactate production, glucose consumption, and citrate synthase and 3-OH acyl CoA dehydrogenase activities. Our data demonstrate that tadalafil is able to modulate energy homeostasis in mouse skeletal muscle cells, depending on the treatment length and dose.

Ischemic Factors and Deformation Influence Metabolism of Engineered Skeletal Muscle

2007 ◽  
Author(s):  
Cees W. J. Oomens ◽  
Debby Gawlitta ◽  
Carlijn V. C. Bouten ◽  
Frank P. T. Baaijens
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Lactate Production ◽  
Glucose Consumption ◽  
Model System ◽  
Tissue Viability ◽  
Tissue Ischemia ◽  
Tissue Degeneration ◽  
The Relationship ◽  
Tissue Compression

Tissue compression may induce collapse of blood vessels resulting in tissue ischemia (insufficient blood flow). In addition, cellular deformation due to tissue compression may initiate tissue degeneration. These are two of the hypotheses that have been proposed to explain the development of (deep) pressure ulcers. Skeletal muscle tissue, in particular, is susceptible to compression induced breakdown. A model system was developed to investigate the relative contributions of deformation and ischemic factors to compromising tissue viability or metabolism. A theoretical model, describing the relationship between glucose consumption, lactate production and cell death was developed.

scholarly journals Response of C2C12 Myoblasts to Hypoxia: The Relative Roles of Glucose and Oxygen in Adaptive Cellular Metabolism

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Li ◽  
Zhen-Fu Hu ◽  
Bin Chen ◽  
Guo-Xin Ni
Keyword(s):  
Oxygen Consumption ◽  
Glucose Concentration ◽  
Cellular Response ◽  
Cell Function ◽  
Cell Metabolism ◽  
Lactate Production ◽  
Cellular Metabolism ◽  
Glucose Consumption ◽  
C2c12 Cells ◽  
Low Oxygen

Background. Oxygen and glucose are two important nutrients for mammalian cell function. In this study, the effect of glucose and oxygen concentrations on C2C12 cellular metabolism was characterized with an emphasis on detecting whether cells show oxygen conformance (OC) in response to hypoxia.Methods. After C2C12 cells being cultured in the levels of glucose at 0.6 mM (LG), 5.6 mM (MG), or 23.3 mM(HG) under normoxic or hypoxic (1% oxygen) condition, cellular oxygen consumption, glucose consumption, lactate production, and metabolic status were determined. Short-term oxygen consumption was measured with a novel oxygen biosensor technique. Longer-term measurements were performed with standard glucose, lactate, and cell metabolism assays.Results. It was found that oxygen depletion in normoxia is dependent on the glucose concentration in the medium. Cellular glucose uptake and lactate production increased significantly in hypoxia than those in normoxia. In hypoxia the cellular response to the level of glucose was different to that in normoxia. The metabolic activities decreased while glucose concentration increased in normoxia, while in hypoxia, metabolic activity was reduced in LG and MG, but unchanged in HG condition. The OC phenomenon was not observed in the present study.Conclusions. Our findings suggested that a combination of low oxygen and low glucose damages the viability of C2C12 cells more seriously than low oxygen alone. In addition, when there is sufficient glucose, C2C12 cells will respond to hypoxia by upregulating anaerobic respiration, as shown by lactate production.

Sign in / Sign up

Export Citation Format

Share Document