CoChat
Sign Up
Cited by 173Metabolism, Diabetes, and CancerMuscle metabolism and nutritionAdipose Tissue and Metabolism

Malonyl-coa and carnitine in regulation of fat oxidation in human skeletal muscle during exercise

Open access
Roepstorff, Carsten, Halberg, Nils, Hillig, Thore, Saha, Asish K., Ruderman, Neil B., Wojtaszewski, Jørgen F. P., Richter, Erik A., Kiens, Bente·2005·American Journal of Physiology-Endocrinology and Metabolism
DOI 10.1152/ajpendo.00379.2004
Open this paper in CoChat — free account

Abstract

Intracellular mechanisms regulating fat oxidation were investigated in human skeletal muscle during exercise. Eight young, healthy, moderately trained men performed bicycle exercise (60 min, 65% peak O2 consumption) on two occasions, where they ingested either 1) a high-carbohydrate diet (H-CHO) or 2) a low-carbohydrate diet (L-CHO) before exercise to alter muscle glycogen content as well as to induce, respectively, low and high rates of fat oxidation. Leg fat oxidation was 122% higher during exercise in L-CHO than in H-CHO (P < 0.001). In keeping with this, the activity of alpha2-AMP-activated protein kinase (alpha2-AMPK) was increased twice as much in L-CHO as in H-CHO (P < 0.01) at 60 min of exercise. However, acetyl-CoA carboxylase (ACC)beta Ser221 phosphorylation was increased to the same extent (6-fold) under the two conditions. The concentration of malonyl-CoA was reduced 13% by exercise in both conditions (P < 0.05). Pyruvate dehydrogenase activity was higher during exercise in H-CHO than in L-CHO (P < 0.01). In H-CHO only, the concentrations of acetyl-CoA and acetylcarnitine were increased (P < 0.001), and the concentration of free carnitine was decreased (P < 0.01), by exercise. The data suggest that a decrease in the concentration of malonyl-CoA, secondary to alpha2-AMPK activation and ACC inhibition (by phosphorylation), contributes to the increase in fat oxidation observed at the onset of exercise regardless of muscle glycogen levels. They also suggest that, with high muscle glycogen, the availability of free carnitine may limit fat oxidation during exercise, due to its increased use for acetylcarnitine formation.

Integrity signals

Registry

Crossref · 10.1152/ajpendo.00379.2004

Cites

50 of 50 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

We couldn’t retrieve this paper’s full text, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The reduction in intra-muscular free carnitine limits the ability of CPT-1 to transport long chain FA to the mitochondria.

    “Thus, the reduction in intra-muscular free carnitine limits the ability of CPT-1 to transport long chain FA to the mitochondria [157].”

    From Regulation of Energy Substrate Metabolism in Endurance Exercise (2021) · cites this paper as [157]

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Roepstorff, C., Halberg, N., Hillig, T., Saha, A. K., Ruderman, N. B., Wojtaszewski, J. F. P., Richter, E. A., & Kiens, B.
Affiliations
University of Copenhagen (DK)
ORCID
Venue
American Journal of Physiology-Endocrinology and Metabolism
Publisher
American Physiological Society
Published
2005-01
Volume
288
Issue
1
Pages
E133-E142
ISSN
  • 0193-1849 (ISSN-L)
  • 1522-1555
DOI
10.1152/ajpendo.00379.2004
OpenAlex
W2143035710
Cited by
173
References
50
Citations by year
2026: 1 · 2025: 3 · 2024: 3 · 2023: 3 · 2022: 3 · 2021: 5 · 2020: 5 · 2019: 7 · 2018: 6 · 2017: 8 · 2016: 7 · 2015: 9 · 2014: 15 · 2013: 9 · 2012: 12
FWCI
3.43
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • American Journal of Physiology-Endocrinology and Metabolism (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Research at the University of Copenhagen (University of Copenhagen) (submittedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology › Adipose Tissue and Metabolism
Keywords
fat oxidation, skeletal muscle, physical activity, malonyl-CoA, L-carnitine, acetyl-L-carnitine, acetyl-CoA carboxylase, muscle glycogen, low-carbohydrate diet, pyruvate dehydrogenase, acetyl-CoA, free carnitine
MeSH terms
Acetyl-CoA Carboxylase, Acetyl Coenzyme A, Acetylcarnitine, Adenylate Kinase, Adult, Carnitine, Dietary Carbohydrates, Fatty Acids, Glucose, Glycogen, Heart Rate, Humans, Insulin, Male, Malonyl Coenzyme A, Oxidation-Reduction, Pyruvate Dehydrogenase Complex, Exercise, Muscle, Skeletal

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review