Influence of exercise duration on serum insulin-like growth factor and its binding proteins in athletes

  • U. N. Nguyen
  • F. Mougin
  • M. L. Simon-Rigaud
  • J. D. Rouillon
  • P. Marguet
  • J. Regnard
ORIGINAL ARTICLE

Abstract

The changes in circulating concentrations of insulin-like growth factors during exercise have to date remained incomplete in their documentation. Therefore, we examined in 25 healthy athletes the effects of three different durations of three types of exercise – incremental ergometer cycling exercise (ICE), long-distance Nordic ski race (NSR) and a treadmill-simulated soccer game (TSG) lasting 20 min, 3 h, and 2 × 45 min separated by a 15-min half-time rest respectively, on plasma concentrations of growth hormone ([GH]), insulin-like growth factor-1 ([IGF-I]) and its binding proteins 1 and 3 ([IGFBP-1], [IGFBP-3]). Compared to baseline, serum [GH] increased by 15.2-fold after ICE (P < 0.001), 2.9-fold after NSR (P < 0.01) and 4.6-fold after TSG. Serum [IGF-I] rose by 11.9% after ICE (P < 0.001), while it decreased by −14.6% after NSR (P < 0.001) and was unchanged after TSG. Serum [IGFBP-1] was slightly increased (1.7-fold) after ICE (P < 0.01), but increased markedly (11.8-fold) after NSR (P < 0.001) and by 6.3-fold after the second session of TSG (P < 0.01) (it remained unchanged at the end of the first period of TSG, i.e. after 45-min exercise). The [IGFBP-3] increased by 14.7% after ICE (P < 0.001) and by 6% after TSG (P < 0.05) while it did not change after NSR. From our results it would appear that [IGFBP-1] increase to bind free IGF and hinder their insulin-like action during long-term exercise (lasting beyond 45 min). It is suggested that IGFBP-1 might thus contribute both to preventing hypoglycaemic action of IGF and to facilitating glucose uptake by muscle cells when muscle glycogen stores become deplete.

Key words Insulin-like growth factor-1 Insulin-like growth factor binding proteins-1 and 3 Nordic ski Soccer game Incremental exercise 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • U. N. Nguyen
    • 1
  • F. Mougin
    • 2
  • M. L. Simon-Rigaud
    • 3
  • J. D. Rouillon
    • 2
  • P. Marguet
    • 4
  • J. Regnard
    • 1
  1. 1.Laboratoire de Physiologie - Explorations Fonctionnelles Rénales et Métaboliques, Centre Hospitalier Universaire (CHU), J. Minjoz, Boulevard Fleming, F-25030 Besançon Cedex, FranceFR
  2. 2.Laboratoire des Sciences du Sport. Unite de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives F-25030 Besançon Cedex, FranceFR
  3. 3.Service de Physiopathologie Respiratoire – Médecine du Sport, CHU de Besançon, F-25030 Besançon Cedex, FranceFR
  4. 4.Service d'Urgences, Centre Hospitalier General de Pontarlier, F-25300 Pontarlier, FranceFR

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