The effect of maximal physical exercise on relationships between the growth hormone (GH) and insulin-like growth factor 1 (IGF-1) and transcriptional activity of CYP1A2 in young ice hockey players

J Sports Med Phys Fitness. 2015 Mar;55(3):158-63. Epub 2014 Jul 16.


Background: The maximal physical exercise influences on changes in GH, IGF-1 concentrations and activity of CYP1A2. The aim of this study was to answer the question whether the change of endogenous GH and IGF-1 influenced the expression of CYP1A2 and whether these changes correlate with others parameters of blood and test.

Methods: The twenty ice young hockey players were subjected to maximal exercise cycle test. The test duration was mean 21.0 ± 2.4 min, and work done was mean 3261.3 ± 558.3 J/kg. In blood samples collected before and after the exercise were evaluated: concentrations of GH and IGF-1 which were determined in the serum by IRMA method and the transcriptional activity of CYP1A2 in RNA isolated from whole blood by the QRT-PCR reaction.

Results: Before the exercise the median of GH was mean 0.31 ± 0.23 μU/mL and after the exercise increased to mean 21.6 ± 16.6 μU/mL (P<0.001). Mean of serum IGF-1 level before the exercise and immediately after test did not change. Statistically significant increase in value of Ct for CYP1A2 (P<0.001) was found.

Conclusion: The results of the study showed that: an intense exercise of young ice hockey players led to a significant increase in GH concentration, which caused the Ct values of CYP1A2 increase, whereas IGF-1 did not change. GH and IGF-1 levels after the exercise depended on the work done and the relative levels of CYP1A2 expression correlated with the time and the amount of work done by the athletes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Athletes*
  • Cytochrome P-450 CYP1A2 / genetics*
  • Cytochrome P-450 CYP1A2 / metabolism
  • Exercise Test
  • Gene Expression*
  • Growth Hormone / blood*
  • Hockey
  • Humans
  • Insulin-Like Growth Factor I / analysis*
  • Physical Exertion*
  • RNA / metabolism


  • RNA
  • Insulin-Like Growth Factor I
  • Growth Hormone
  • CYP1A2 protein, human
  • Cytochrome P-450 CYP1A2