Fatty Acid Oxidation by Skeletal Muscle During Rest and Activity

1958 ◽  
Vol 194 (2) ◽  
pp. 379-386 ◽  
Author(s):  
Irving B. Fritz ◽  
Don G. Davis ◽  
Robert H. Holtrop ◽  
Harold Dundee
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Latissimus Dorsi ◽  
Acid Metabolism ◽  
Fat Metabolism ◽  
Acid Oxidation ◽  
Stimulation Of

The metabolism of C14-labeled acetate, octanoate and palmitate by isolated skeletal muscle (latissimus dorsi and diaphragm) from normal, fed rats has been examined. The rates at which these substrates were converted to C14O2 have been shown to vary with concentration, temperature, functional state of the muscle, and the presence of albumin. Increased concentration of fatty acids led to enhanced conversion of substrate to C14O2. Electrical stimulation of muscles under tension resulted in approximately a 60% increase in oxygen consumption and about a 100% rise in fatty acid oxidation. The addition of glucose did not alter the rate of fatty acid metabolism by muscle. The addition of bovine albumin at concentrations up to approximately 1 µm albumin/7 µm palmitate resulted in augmented palmitic acid oxidation. However, at concentrations of albumin greater than 1 µm albumin/7 µm palmitate, palmitic acid degradation by resting diaphragm was inhibited, suggesting a firmer binding of fatty acid to albumin. The Q10 for palmitic acid oxidation by resting diaphragm was 2.23 in the absence of added albumin between 25° and 37°C. The data are discussed in relation to the present concepts of fat metabolism and transport in vivo. It is suggested that fat degradation in isolated muscle may provide an energy source during activity.

scholarly journals Stimulation of Mitochondrial Fatty Acid Oxidation by Growth Hormone in Human Fibroblasts1

1997 ◽  
Vol 82 (12) ◽  
pp. 4208-4213 ◽  
Author(s):  
Kin-Chuen Leung ◽  
Ken K. Y. Ho
Keyword(s):  
Fatty Acid ◽  
Growth Factor ◽  
Lipid Oxidation ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Stimulation Of

In vivo administration of GH induces lipolysis and lipid oxidation. However, it is not clear whether the stimulation of lipid oxidation is a direct effect of GH or is driven by increased substrate supply secondary to lipolysis. An in vitro bioassay has been established for assessing β-oxidation of fatty acids in mitochondria, based on the measurement of conversion of tritiated palmitic acid to 3H2O by fibroblasts in culture. We have modified this assay to investigate whether GH stimulates fatty acid oxidation. GH stimulated oxidation of palmitic acid maximally by 26.7 ± 2.5% (mean ± sem; P < 0.0001). The stimulation was biphasic, with the oxidation rate increasing with increasing GH concentration to a peak response at 1.5 nmol/L and declining to a level not significantly different from control thereafter. Insulin-like growth factor-I at concentrations of up to 250 nmol/L had no significant effect on fatty acid oxidation. GH-binding protein attenuated the effect of GH. An anti-GH receptor (GHR) antibody (MAb263), which dimerizes the receptor and induces GH-like biological actions, significantly stimulated fatty acid oxidation. Another anti-GHR antibody (MAb5), which prevents receptor dimerization, suppressed GH action. In summary, GH directly stimulated fatty acid oxidation, an action not mediated by insulin-like growth factor-I. Dimerization of GHRs was necessary for this effect. This bioassay is a practical tool for studying the regulatory effects of GH on lipid oxidation.

scholarly journals Retinoic Acid Increases Fatty Acid Oxidation and Irisin Expression in Skeletal Muscle Cells and Impacts Irisin In Vivo

2018 ◽  
Vol 46 (1) ◽  
pp. 187-202 ◽  
Author(s):  
Jaume Amengual ◽  
Francisco J. García-Carrizo ◽  
Andrea Arreguín ◽  
Hana Mušinović ◽  
Nuria Granados ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Retinoic Acid ◽  
Fatty Acid ◽  
Glucose Uptake ◽  
Fatty Acid Oxidation ◽  
Kinase Inhibitor ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Protective Effects

Background/Aims: All-trans retinoic acid (ATRA) has protective effects against obesity and metabolic syndrome. We here aimed to gain further insight into the interaction of ATRA with skeletal muscle metabolism and secretory activity as important players in metabolic health. Methods: Cultured murine C2C12 myocytes were used to study direct effects of ATRA on cellular fatty acid oxidation (FAO) rate (using radioactively-labelled palmitate), glucose uptake (using radioactively-labelled 2-deoxy-D-glucose), triacylglycerol levels (by an enzymatic method), and the expression of genes related to FAO and glucose utilization (by RT-real time PCR). We also studied selected myokine production (using ELISA and immunohistochemistry) in ATRA-treated myocytes and intact mice. Results: Exposure of C2C12 myocytes to ATRA led to increased fatty acid consumption and decreased cellular triacylglycerol levels without affecting glucose uptake, and induced the expression of the myokine irisin at the mRNA and secreted protein level in a dose-response manner. ATRA stimulatory effects on FAO-related genes and the Fndc5 gene (encoding irisin) were reproduced by agonists of peroxisome proliferator-activated receptor β/δ and retinoid X receptors, but not of retinoic acid receptors, and were partially blocked by an AMP-dependent protein kinase inhibitor. Circulating irisin levels were increased by 5-fold in ATRA-treated mice, linked to increased Fndc5 transcription in liver and adipose tissues, rather than skeletal muscle. Immunohistochemistry analysis of FNDC5 suggested that ATRA treatment enhances the release of FNDC5/irisin from skeletal muscle and the liver and its accumulation in interscapular brown and inguinal white adipose depots. Conclusion: These results provide new mechanistic insights on how ATRA globally stimulates FAO and enhances irisin secretion, thereby contributing to leaning effects and improved metabolic status.

scholarly journals The Suppressor of Cytokine Signaling 3 Inhibits Leptin Activation of AMP-Kinase in Cultured Skeletal Muscle of Obese Humans

2006 ◽  
Vol 91 (9) ◽  
pp. 3592-3597 ◽  
Author(s):  
Gregory R. Steinberg ◽  
Andrew J. McAinch ◽  
Michael B. Chen ◽  
Paul E. O’Brien ◽  
John B. Dixon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Metabolism ◽  
Leptin Resistance ◽  
Cytokine Signaling ◽  
Acid Oxidation ◽  
Amp Kinase ◽  
Ampk Signaling ◽  
Obese Subjects

Abstract Context: Leptin is thought to regulate whole-body adiposity and insulin sensitivity, at least in part, by stimulating fatty acid metabolism via activation of AMP-kinase (AMPK) in skeletal muscle. Human obesity is associated with leptin resistance, and recent studies have demonstrated that hypothalamic expression of the suppressors of cytokine signaling 3 (SOCS3) regulates leptin sensitivity in rodents. Objective: The objective of the study was to investigate the effects of leptin on fatty acid oxidation and AMPK signaling in primary myotubes derived from lean and obese skeletal muscle and evaluate the contribution of SOCS3 to leptin resistance and AMPK signaling in obese humans. Results: We demonstrate that leptin stimulates AMPK activity and increases AMPK Thr172 and acetyl-CoA carboxylase-β Ser222 phosphorylation and fatty acid oxidation in lean myotubes but that in obese subjects leptin-dependent AMPK signaling and fatty acid oxidation are suppressed. Reduced activation of AMPK was associated with elevated expression of IL-6 (∼3.5-fold) and SOCS3 mRNA (∼2.5-fold) in myotubes of obese subjects. Overexpression of SOCS3 via adenovirus-mediated infection in lean myotubes to a similar degree as observed in obese myotubes prevented leptin but not AICAR (5-amino-imidazole-4-carboxamide-1-β-d-ribofuranoside) activation of AMPK signaling. Conclusions: These data demonstrate that SOCS3 inhibits leptin activation of AMPK. These data suggest that this impairment of leptin signaling in skeletal muscle may contribute to the aberrant regulation of fatty acid metabolism observed in obesity and that pharmacological activation of AMPK may be an effective therapy to bypass SOCS3-mediated skeletal muscle leptin resistance for the treatment of obesity-related disorders.

scholarly journals Susceptibility of podocytes to palmitic acid is regulated by fatty acid oxidation and inversely depends on acetyl-CoA carboxylases 1 and 2

2014 ◽  
Vol 306 (4) ◽  
pp. F401-F409 ◽  
Author(s):  
Kapil Kampe ◽  
Jonas Sieber ◽  
Jana Marina Orellana ◽  
Peter Mundel ◽  
Andreas Werner Jehle
Keyword(s):  
Type 2 Diabetes ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Er Stress ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Genome Wide Association Studies ◽  
Acetyl Coa ◽  
Stimulation Of

Type 2 diabetes is characterized by dyslipidemia with elevated free fatty acids (FFAs). Loss of podocytes is a hallmark of diabetic nephropathy, and podocytes are susceptible to saturated FFAs, which induce endoplasmic reticulum (ER) stress and podocyte death. Genome-wide association studies indicate that expression of acetyl-CoA carboxylase (ACC) 2, a key enzyme of fatty acid oxidation (FAO), is associated with proteinuria in type 2 diabetes. Here, we show that stimulation of FAO by aminoimidazole-4-carboxamide-1β-d-ribofuranoside (AICAR) or by adiponectin, activators of the low-energy sensor AMP-activated protein kinase (AMPK), protects from palmitic acid-induced podocyte death. Conversely, inhibition of carnitine palmitoyltransferase (CPT-1), the rate-limiting enzyme of FAO and downstream target of AMPK, augments palmitic acid toxicity and impedes the protective AICAR effect. Etomoxir blocked the AICAR-induced FAO measured with tritium-labeled palmitic acid. The beneficial effect of AICAR was associated with a reduction of ER stress, and it was markedly reduced in ACC-1/-2 double-silenced podocytes. In conclusion, the stimulation of FAO by modulating the AMPK-ACC-CPT-1 pathway may be part of a protective mechanism against saturated FFAs that drive podocyte death. Further studies are needed to investigate the potentially novel therapeutic implications of these findings.

scholarly journals Stimulation of astrocyte fatty acid oxidation by thyroid hormone is protective against ischemic stroke-induced damage

2016 ◽  
Vol 37 (2) ◽  
pp. 514-527 ◽  
Author(s):  
Naomi L Sayre ◽  
Mikaela Sifuentes ◽  
Deborah Holstein ◽  
Sheue-yann Cheng ◽  
Xuguang Zhu ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Fatty Acid ◽  
Stroke Volume ◽  
Fatty Acid Oxidation ◽  
Glucose Deprivation ◽  
Acid Oxidation ◽  
Atp Production ◽  
Stimulation Of

We previously demonstrated that stimulation of astrocyte mitochondrial ATP production via P2Y1 receptor agonists was neuroprotective after cerebral ischemic stroke. Another mechanism that increases ATP production is fatty acid oxidation (FAO). We show that in primary human astrocytes, FAO and ATP production are stimulated by 3,3,5 triiodo-l-thyronine (T3). We tested whether T3-stimulated FAO enhances neuroprotection, and show that T3 increased astrocyte survival after either hydrogen peroxide exposure or oxygen glucose deprivation. T3-mediated ATP production and protection were both eliminated with etomoxir, an inhibitor of FAO. T3-mediated protection in vitro was also dependent on astrocytes expressing HADHA (hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase), which we previously showed was critical for T3-mediated FAO in fibroblasts. Consistent with previous reports, T3-treatment decreased stroke volumes in mice. While T3 decreased stroke volume in etomoxir-treated mice, T3 had no protective effect on stroke volume in HADHA +/− mice or in mice unable to upregulate astrocyte-specific energy production. In vivo, 95% of HADHA co-localize with glial-fibrillary acidic protein, suggesting the effect of HADHA is astrocyte mediated. These results suggest that astrocyte-FAO modulates lesion size and is required for T3-mediated neuroprotection post-stroke. To our knowledge, this is the first report of a neuroprotective role for FAO in the brain.

AMP-activated protein kinase, a metabolic master switch: possible roles in Type 2 diabetes

1999 ◽  
Vol 277 (1) ◽  
pp. E1-E10 ◽  
Author(s):  
W. W. Winder ◽  
D. G. Hardie
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Ampk Activation ◽  
Signaling System ◽  
Ampk Signaling ◽  
Stimulation Of

Adenosine 5′-monophosphate-activated protein kinase (AMPK) now appears to be a metabolic master switch, phosphorylating key target proteins that control flux through metabolic pathways of hepatic ketogenesis, cholesterol synthesis, lipogenesis, and triglyceride synthesis, adipocyte lipolysis, and skeletal muscle fatty acid oxidation. Recent evidence also implicates AMPK as being responsible for mediating the stimulation of glucose uptake induced by muscle contraction. In addition, the secretion of insulin by insulin secreting (INS-1) cells in culture is modulated by AMPK activation. The net effect of AMPK activation is stimulation of hepatic fatty acid oxidation and ketogenesis, inhibition of cholesterol synthesis, lipogenesis, and triglyceride synthesis, inhibition of adipocyte lipolysis and lipogenesis, stimulation of skeletal muscle fatty acid oxidation and muscle glucose uptake, and modulation of insulin secretion by pancreatic β-cells. In skeletal muscle, AMPK is activated by contraction. Type 2 diabetes mellitus is likely to be a disease of numerous etiologies. However, defects or disuse (due to a sedentary lifestyle) of the AMPK signaling system would be predicted to result in many of the metabolic perturbations observed in Type 2 diabetes mellitus. Increased recruitment of the AMPK signaling system, either by exercise or pharmaceutical activators, may be effective in correcting insulin resistance in patients with forms of impaired glucose tolerance and Type 2 diabetes resulting from defects in the insulin signaling cascade.

scholarly journals Toll-like receptor 4 modulates skeletal muscle substrate metabolism

2010 ◽  
Vol 298 (5) ◽  
pp. E988-E998 ◽  
Author(s):  
Madlyn I. Frisard ◽  
Ryan P. McMillan ◽  
Julie Marchand ◽  
Kristin A. Wahlberg ◽  
Yaru Wu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Substrate Metabolism

Toll-like receptor 4 (TLR4), a protein integral to innate immunity, is elevated in skeletal muscle of obese and type 2 diabetic humans and has been implicated in the development of lipid-induced insulin resistance. The purpose of this study was to examine the role of TLR4 as a modulator of basal (non-insulin-stimulated) substrate metabolism in skeletal muscle with the hypothesis that its activation would result in reduced fatty acid oxidation and increased partitioning of fatty acids toward neutral lipid storage. Human skeletal muscle, rodent skeletal muscle, and skeletal muscle cell cultures were employed to study the functional consequences of TLR4 activation on glucose and fatty acid metabolism. Herein, we demonstrate that activation of TLR4 with low (metabolic endotoxemia) and high (septic conditions) doses of LPS results in increased glucose utilization and reduced fatty acid oxidation in skeletal muscle and that these changes in metabolism in vivo occur in concert with increased circulating triglycerides. Moreover, animals with a loss of TLR4 function possess increased oxidative capacity in skeletal muscle and present with lower fasting levels of triglycerides and nonesterified free fatty acids. Evidence is also presented to suggest that these changes in substrate metabolism under metabolic endotoxemic conditions are independent of skeletal muscle-derived proinflammatory cytokine production. This report illustrates that skeletal muscle is a target for circulating endotoxin and may provide critical insight into the link between a proinflammatory state and dysregulated metabolism as observed with obesity, type 2 diabetes, and metabolic syndrome.

Contribution of FAT/CD36 to the regulation of skeletal muscle fatty acid oxidation: an overview

2008 ◽  
Vol 194 (4) ◽  
pp. 293-309 ◽  
Author(s):  
G. P. Holloway ◽  
J. J. F. P. Luiken ◽  
J. F. C. Glatz ◽  
L. L. Spriet ◽  
A. Bonen
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation
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