ArticleNutrition & metabolism2013
Supplementation of carnitine leads to an activation of the IGF-1/PI3K/Akt signalling pathway and down regulates the E3 ligase MuRF1 in skeletal muscle of rats.
Article in Nutrition & metabolism, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 24 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
24 citing papers in PubMed, 2 syntheses or guidelines pooled it, 42 citations in OpenAlex.
- L-Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review.Nutrients · 2024Pooled it
- The bright and the dark sides of L-carnitine supplementation: a systematic review.Journal of the International Society of Sports Nutrition · 2020Pooled it
- l-Carnitine Supplementation in Older Women. A Pilot Study on Aging Skeletal Muscle Mass and Function.Nutrients · 2018Trial
- Attrition of amino acids in the life span of broiler chickens.Animal nutrition (Zhongguo xu mu shou yi xue hui) · 2025Review
- Comprehensive review of the expanding roles of the carnitine pool in metabolic physiology: beyond fatty acid oxidation.Journal of translational medicine · 2025Review
- The effect of L-carnitine supplementation on anthropometric and malnutrition status in acute ischemic stroke patients: a triple-blinded randomized clinical trial.BMC nutrition · 2025Article
- Influence of Amino Acids and Exercise on Muscle Protein Turnover, Particularly in Cancer Cachexia.Cancers · 2024Review
- Effects of L-Carnitine Intake on Exercise-Induced Muscle Damage and Oxidative Stress: A Narrative Scoping Review.Nutrients · 2023Article
- L-carnitine prevents lenvatinib-induced muscle toxicity without impairment of the anti-angiogenic efficacy.Frontiers in pharmacology · 2023Article
- Rifaximin enhances the L‑carnitine‑mediated preventive effects on skeletal muscle atrophy in cirrhotic rats by modulating the gut‑liver‑muscle axis.International journal of molecular medicine · 2022Article
- L-Carnitine Combined with Leucine Supplementation Does Not Improve the Effectiveness of Progressive Resistance Training in Healthy Aged Women.The journal of nutrition, health & aging · 2022Article
- HumanInternational journal of biological sciences · 2022Article
- Article
- Pathophysiological mechanisms of statin-associated myopathies: possible role of the ubiquitin-proteasome system.Journal of cachexia, sarcopenia and muscle · 2020Review
- L-Carnitine metabolism, protein turnover and energy expenditure in supplemented and exercised Labrador Retrievers.Journal of animal physiology and animal nutrition · 2020Article
- Article
- Long-term resistance exercise-induced muscular hypertrophy is associated with autophagy modulation in rats.The journal of physiological sciences : JPS · 2018Article
- l-Carnitine Supplementation in Recovery after Exercise.Nutrients · 2018Review
- Potential therapeutic interventions for chronic kidney disease-associated sarcopenia via indoxyl sulfate-induced mitochondrial dysfunction.Journal of cachexia, sarcopenia and muscle · 2017Article
- Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundRecently, it has been shown that carnitine down-regulates genes involved in the ubiquitin-proteasome system (UPS) in muscle of pigs and rats. The mechanisms underlying this observation are yet unknown. Based on the previous finding that carnitine increases plasma IGF-1 concentration, we investigated the hypothesis that carnitine down-regulates genes of the UPS by modulation of the of the IGF-1/PI3K/Akt signalling pathway which is an important regulator of UPS activity in muscle.
methodsMale Sprague-Dawley rats, aged four weeks, were fed either a control diet with a low native carnitine concentration or the same diet supplemented with carnitine (1250 mg/kg diet) for four weeks. Components of the UPS and IGF-1/PI3K/Akt signalling pathway in skeletal muscle were examined.
resultsRats fed the diet supplemented with carnitine had lower mRNA and protein levels of MuRF1, the most important E3 ubiquitin ligase in muscle, decreased concentrations of ubiquitin-protein conjugates in skeletal muscle and higher IGF-1 concentration in plasma than control rats (P < 0.05). Moreover, in skeletal muscle of rats fed the diet supplemented with carnitine there was an activation of the PI3K/Akt signalling pathway, as indicated by increased protein levels of phosphorylated (activated) Akt1 (P < 0.05).
conclusionThe present study shows that supplementation of carnitine markedly decreases the expression of MuRF1 and concentrations of ubiquitinated proteins in skeletal muscle of rats, indicating a diminished degradation of myofibrillar proteins by the UPS. The study moreover shows that supplementation of carnitine leads to an activation of the IGF-1/PI3K/Akt signalling pathway which in turn might contribute to the observed down-regulation of MuRF1 and muscle protein ubiquitination.
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.