Changes in muscle free carnitine and acetylcarnitine with increasing work intensity in the Thoroughbred horse.
Abstract: Treadmill exercise in Thoroughbred horses of 2 min duration and increasing intensity resulted in increased formation and accumulation of acetylcarnitine in the working middle gluteal muscle. At high work intensities a plateau in acetylcarnitine formation was reached corresponding to approximately 70% of the total carnitine pool (approx. 30 mmol.kg-1 dry muscle). Formation of acetylcarnitine was mirrored by an equal fall in the free carnitine content, which stabilised, at the highest work intensities, at around 8 mmol.kg-1 dry muscle. Acetylcarnitine and carnitine reached their point of maximum change at a work intensity just below that resulting in the rapid production and accumulation of lactate and glycerol 3-phosphate. It is possible that the formation of acetylcarnitine is important in the regulation of the intramitochondrial acetyl CoA/CoA ratio; equally these changes may represent a blocking mechanism aimed at preventing the transfer of unwanted free fatty acids (as acylcarnitines) into the mitochondria at work intensities where they could contribute little to energy production.
Publication Date: 1990-01-01 PubMed ID: 2335175DOI: 10.1007/BF00846025Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research study investigates the effect of increasing work intensity on levels of muscle free carnitine and acetylcarnitine in Thoroughbred horses.
Study Overview
The study comprised of treadmill exercises in Thoroughbred horses for 2 minutes with an incremental intensity. The focus of the experiment was to observe how increased work intensities affected the formation and accumulation of acetylcarnitine in the gluteal muscles of the horses.
Results and Findings
Major findings from the study were:
- With the increase in work intensity, there was a significant rise in the formation and build-up of acetylcarnitine, reaching supremacy at about 70% of the total carnitine pool or approximately 30 mmol.kg-1 dry muscle.
- The increase in acetylcarnitine was balanced by an equal decrease in free carnitine content, which plateaued at nearly 8 mmol.kg-1 dry muscle at the highest work intensities.
- The points of maximal change for both acetylcarnitine and free carnitine were recorded at a work intensity slightly below the level resulting in the rapid production and accumulation of lactate and glycerol 3-phosphate, which are by-products of glucose metabolism.
Possible Implications
The following possible implications were discussed in the research:
- Acetylcarnitine formation could play a pivotal role in the regulation of the intramitochondrial acetyl CoA/CoA ratio, impacting the energy metabolism in the cell. It envelopes the process of conversion of acetyl CoA to acetylcarnitine as well as its reverse reaction, which is important for energy production.
- The alterations in acetylcarnitine and free carnitine levels may also signify a mechanism aimed at avoiding the transfer of unnecessary free fatty acids into the mitochondria, which might otherwise contribute insufficiently towards energy production at higher work intensities.
Cite This Article
APA
Harris RC, Foster CV.
(1990).
Changes in muscle free carnitine and acetylcarnitine with increasing work intensity in the Thoroughbred horse.
Eur J Appl Physiol Occup Physiol, 60(2), 81-85.
https://doi.org/10.1007/BF00846025 Publication
Researcher Affiliations
- Department of Comparative Physiology, Animal Health Trust, Newmarket, Suffolk, England.
MeSH Terms
- Acetylcarnitine / metabolism
- Animal Husbandry
- Animals
- Carnitine / analogs & derivatives
- Carnitine / metabolism
- Female
- Glycerophosphates / metabolism
- Horses / physiology
- Lactates / metabolism
- Lactic Acid
- Male
- Muscles / metabolism
- Physical Exertion
- Rest
References
This article includes 17 references
- Pearson DJ, Tubbs PK. Carnitine and derivatives in rat tissues.. Biochem J 1967 Dec;105(3):953-63.
- Snow DH, Guy PS. Percutaneous needle muscle biopsy in the horse.. Equine Vet J 1976 Oct;8(4):150-5.
- Foster CV, Harris RC. Formation of acetylcarnitine in muscle of horse during high intensity exercise.. Eur J Appl Physiol Occup Physiol 1987;56(6):639-42.
- Carter AL, Lennon DL, Stratman FW. Increased acetyl carnitine in rat skeletal muscle as a result of high-intensity short-duration exercise. Implications in the control of pyruvate dehydrogenase activity.. FEBS Lett 1981 Apr 6;126(1):21-4.
- Brecher P. The interaction of long-chain acyl CoA with membranes.. Mol Cell Biochem 1983;57(1):3-15.
- Snow DH, Harris RC, Gash SP. Metabolic response of equine muscle to intermittent maximal exercise.. J Appl Physiol (1985) 1985 May;58(5):1689-97.
- Bookelman H, Trijbels JM, Sengers RC, Janssen AJ, Veerkamp JH, Stadhouders AM. Pyruvate oxidation in rat and human skeletal muscle mitochondria.. Biochem Med 1978 Dec;20(3):395-403.
- Uziel G, Garavaglia B, Di Donato S. Carnitine stimulation of pyruvate dehydrogenase complex (PDHC) in isolated human skeletal muscle mitochondria.. Muscle Nerve 1988 Jul;11(7):720-4.
- Bieber LL. Carnitine.. Annu Rev Biochem 1988;57:261-83.
- Alkonyi I, Kerner J, Sándor A. The possible role of carnitine and carnitine acetyl-transferase in the contracting frog skeletal muscle.. FEBS Lett 1975 Apr 1;52(2):265-8.
- Christiansen RZ, Bremer J. Active transport of butyrobetaine and carnitine into isolated liver cells.. Biochim Biophys Acta 1976 Nov 2;448(4):562-77.
- MARQUIS NR, FRITZ IB. ENZYMOLOGICAL DETERMINATION OF FREE CARNITINE CONCENTRATIONS IN RAT TISSUES.. J Lipid Res 1964 Apr;5:184-7.
- Harris RC, Hultman E, Nordesjö LO. Glycogen, glycolytic intermediates and high-energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest. Methods and variance of values.. Scand J Clin Lab Invest 1974 Apr;33(2):109-20.
- Harris RC, Marlin DJ, Snow DH. Metabolic response to maximal exercise of 800 and 2,000 m in the thoroughbred horse.. J Appl Physiol (1985) 1987 Jul;63(1):12-9.
- Garland PB, Randle PJ. Control of pyruvate dehydrogenase in the perfused rat heart by the intracellular concentration of acetyl-coenzyme A.. Biochem J 1964 Apr;91(1):6C-7C.
- Harris RC, Foster CV, Hultman E. Acetylcarnitine formation during intense muscular contraction in humans.. J Appl Physiol (1985) 1987 Jul;63(1):440-2.
- Childress CC, Sacktor B, Traynor DR. Function of carnitine in the fatty acid oxidase-deficient insect flight muscle.. J Biol Chem 1967 Feb 25;242(4):754-60.
Citations
This article has been cited 3 times.- Heinonen OJ. Carnitine and physical exercise. Sports Med 1996 Aug;22(2):109-32.
- el-Hayek R, Valdivia C, Valdivia HH, Hogan K, Coronado R. Activation of the Ca2+ release channel of skeletal muscle sarcoplasmic reticulum by palmitoyl carnitine. Biophys J 1993 Aug;65(2):779-89.
- Friolet R, Hoppeler H, Krähenbühl S. Relationship between the coenzyme A and the carnitine pools in human skeletal muscle at rest and after exhaustive exercise under normoxic and acutely hypoxic conditions. J Clin Invest 1994 Oct;94(4):1490-5.
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