Download PDF
Horm Metab Res 2005; 37(9): 566-571
DOI: 10.1055/s-2005-870424
Review
© Georg Thieme Verlag KG Stuttgart · New York

Effects of L-carnitine on Thyroid Hormone Metabolism and on Physical Exercise Tolerance

S.  Benvenga1
  • 1 Sezione di Endocrinologia del Dipartimento Clinico Sperimentale di Medicina e Farmacologia, University of Messina School of Medicine, and Programma di Endocrinologia Molecolare Clinica, Azienda Ospedaliera Universitaria Policlinico Gaetano Martino, 98125 Messina, Italy
Further Information

Publication History

Received 4 November 2004

Accepted after Revision 24 February 2005

Publication Date:
20 September 2005 (online)

Also available at
    Permissions and Reprints

Abstract

L-carnitine (CARN) is a water-soluble, naturally occurring quaternary amine ubiquitous in biological fluids and animal tissues; in these tissues, CARN plays an important role in energy metabolism. Skeletal muscles store about 95 % of a total of 20 g CARN contained in the adult human body, but high-intensity physical exercise decreases the CARN muscle content. The daily allowance of CARN is mainly satisfied by diet. Keeping in mind important interstudy differences, the general conclusion is that CARN supplementation may enhance athletic performance when coupled to physical exercise itself. Healthy, essentially sedentary persons and untrained individuals do not benefit from supplementation, and certainly not if CARN is administered for a few days. CARN was also shown to modulate thyroid hormone action in peripheral tissues, the most frequent modulation observed being inhibition.

Key words

L-carnitine · Nutrients · Sports · Physical exercise · Thyroid hormone modulators

References

  • 1 Loster H. Biochemical fundamentals of the effects of carnitine. In: Loster H (ed) Carnitine and Cardiovascular Diseases. Bochum; Ponte Press Verlags 2003: 3-48
    Google Scholar
  • 2 Anonymous . Recipes of All Nations. New York; WM Wise & Co, USA 1935: 779-781
    Google Scholar
  • 3 Tamai I, Ohashi R, Nezu J, Yabuchi H, Oku A, Shimane M, Say Y, Tsuji A. Molecular and functional identification of sodium ion-dependent, high affinity human carnitine transporter (OCTN2).  J Biol Chem. 1998;  273 20 378-20 382
    PubMedGoogle Scholar
  • 4 Rebouche C J. Carnitine movement across muscle cell membranes.  Biochem Biophys Acta. 1977;  471 145-155
    PubMedGoogle Scholar
  • 5 Huth P J, Schmidt M J, Hall P V, Fariello R G, Shug A L. The uptake of carnitine by slices of rat cerebral cortex.  J Neurochem. 1981;  36 715-723
    PubMedGoogle Scholar
  • 6 Cederblad G, Lindstedt S, Lundholm K. Concentration of carnitine in human muscle tissue.  Clin Chim Acta. 1974;  53 311-321
    CrossrefPubMedGoogle Scholar
  • 7 Rebouche C J. Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism.  Ann NY Acad Sci. 2004;  1033 30-41
    PubMedGoogle Scholar
  • 8 Arenas J, Huertas R, Campos Y, Diaz A E, Villalon J M, Vilas E. Effects of L-carnitine on the pyruvate dehydrogenase complex and carnitine palmitoyl transferase in muscle athletes.  FEBS Lett. 1994;  341 91-93
    CrossrefPubMedGoogle Scholar
  • 9 Arenas J, Ricoy J R, Encinas A R, Pola P, D’Iddio S, Zeviani M, Di Donato S, Corsi M. Carnitine in muscle, serum and urine of non-professional athletes; effects of physical exercise, training, and L-carnitine administration.  Muscle & Nerve. 1991;  14 598-604
    PubMedGoogle Scholar
  • 10 Lohninger A, Kaiser E, Legenstein E, Staniek H. Carnitine: Metabolism and function. In: Kaiser E, Lohninger A, eds Carnitine, its role in lung and heart disorders. Proceeding of the Satellite Symposium of the Central European Congress of Aenesthesiology (ZAK), Graz (Austria), September 13, 1985. Basel, New York; Karger 1985: 1-25
    Google Scholar
  • 11 Brass E P, Hiatt W R. The role of carnitine and carnitine supplementation during excercise in man and in individuals with special needs.  J Am Coll Nutr. 1998;  17 207-215
    PubMedGoogle Scholar
  • 12 Brass E P. Supplemental carnitine and exercise.  Am J Clin Nutr. 2000;  72 618S-623S
    PubMedGoogle Scholar
  • 13 Brass E P. Carnitine and sports medicine: use or abuse?.  Ann NY Acad Sci. 2004;  1033 67-78
    PubMedGoogle Scholar
  • 14 Benvenga S, Lakshmanan M, Trimarchi F. Carnitine is a naturally occurring inhibitor of thyroid hormone nuclear uptake.  Thyroid. 2000;  12 1043-1050
    PubMedGoogle Scholar
  • 15 Benvenga S, Ruggeri R M, Russo A, Lapa D, Campennì A, Trimarchi F. Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized double-blind, placebo-controlled clinical trial.  J Clin Endocrinol Metab. 2001;  86 3579-3594
    CrossrefPubMedGoogle Scholar
  • 16 Benvenga S, Lapa D, Cannavò S, Trimarchi F. Successive thyroid storms treated with L-carnitine and low doses of methimazole.  Am J Med. 2003;  115 417-418
    CrossrefPubMedGoogle Scholar
  • 17 Neumann G. Effects of L-carnitine in elite athletes. In: Seim H, Loster H (Eds) Carnitine: Pathobiochemical basics and clinical applications. Bochum; Ponte Press Verlags 1996: 61-71
    Google Scholar
  • 18 Luppa D, Loster H. L-carnitine through urine and sweat in athletes in dependence on energy expenditures during training. Bochum; Ponte Press Verlags 1996: 278-279
    Google Scholar
  • 19 Wyss V, Ganzit G P, Rienzi A. Effects of L-carnitine administration on VO2max and aerobic-anaerobic threshold in normoxia and acute hypoxia.  Eur J Appl Physiol. 1990;  60 1-6
    CrossrefPubMedGoogle Scholar
  • 20 Decombaz J, Deriaz O, Acheson K, Gmuender B, Jequier E. Effect of L-carnitine on submaximal exercise metabolism after depletion of muscle glycogen.  Med Sci Sports Exerc. 1993;  25 733-740
    PubMedGoogle Scholar
  • 21 Barnett C, Costill D L, Vukovich M D. et al . Effect of L-carnitine supplementation on muscle and blood carnitine content and lactate accumulation during high-intensity sprint cycling.  Int J Sports Nutr. 1994;  4 280-228
    PubMedGoogle Scholar
  • 22 Vukovich M D, Costill D L, Fink W J. Carnitine supplementation: effect on muscle carnitine and glycogen content during exercise.  Med Sci Sports Exerc. 1994;  26 1122-1129
    PubMedGoogle Scholar
  • 23 Cooper M B, Jones D A, Edwards R H, Corbucci G C, Montanari G, Trevisani C. The effect of marathon running on carnitine metabolism and on some aspects of muscle mitochondrial activities and antioxidant mechanisms.  J Sport Sciences. 1986;  4 79-87
    PubMedGoogle Scholar
  • 24 Dragan G I, Vasiliu A, Georgescu E, Dumas L. Studies concerning chronic and acute effects of L-carnitine on some biological parameters in elite athletes.  Physiologie. 1987;  24 23-28
    PubMedGoogle Scholar
  • 25 Huertas R, Campos Y, Diaz E, Esteban J, Vecchietti L, Montanari G, D’Iddio S, Corbi M, Arenas J. Respiratory chain enzymes in muscle of endurance athletes: effect of L-carnitine.  Biochem Biophys Res Commun. 1992;  188 102-107
    CrossrefPubMedGoogle Scholar
  • 26 Millington D S, Dubag G. Dietary supplement L-carnitine: analysis of different brands to determine bioavailability and content.  Clin Res Reg Affairs. 1993;  10 71-80
    PubMedGoogle Scholar
  • 27 Bremer J. Carnitine - metabolism and function.  Physiol Rev. 1983;  63 1420-1480
    PubMedGoogle Scholar
  • 28 Christinasen R Z, Bremer J. Active transport of butyrobetaine and carnitine into isolated liver cells.  Biochim Biopys Acta. 1976;  444 562-577
    PubMedGoogle Scholar
  • 29 Hiatt W R. Carnitine and peripheral arterial disease.  Ann NY Acad Sci. 2004;  1033 92-98
    PubMedGoogle Scholar
  • 30 Alesci S, De Martino M U, Mirani M, Benvenga S, Trimarchi F, Kino T, Chrousos G O. L-carnitine a nutritional modulator of glucocorticoid receptor functions.  FASEB J. 2003;  17 1553-1555
    PubMedGoogle Scholar
  • 31 Maebashi M, Kawamura N, Sato M, Imamura A, Yoshinaga K, Suzuki M. Urinary excretion of carnitine in patients with hyperthyroidism and hypothyroidism: augmentation by thyroid hormone.  Metabolism. 1977;  26 351-356
    Google Scholar
  • 32 Cederblad G, Engstrom G. Effect of thyroxine treatment on carnitine levels in mice.  Acta Pharmacol et Toxicol. 1978;  43 1-5
    PubMedGoogle Scholar
  • 33 Reed H L. Environmental influences upon thyroid hormone regulation. In: Braverman LE, Utoger RD (eds) Werner and Ingbar’s The thyroid. A fundamental and clinical text. Philadelphia; Lippincott Williams & Wilkins 2005: 219-229
    Google Scholar

Prof. Salvatore Benvenga

Sezione di Endocrinologia del Dipartimento Clinico Sperimentale di Medicina e Farmacologia, padiglione H, 4 piano

Policlinico Universitario Gaetano Martino · 98125 Messina · Italy

Phone: +39 (90) 221 35 17 or 3560

Fax: +39 (90) 221 35 18 or +39 (90) 69 39 17

Email: s.benvenga@me.nettuno.it