Amino Acids

, Volume 42, Issue 4, pp 1405–1416

Acute regulation of IGF-I by alterations in post-exercise macronutrients


    • Department of KinesiologyAuburn University
  • G. Fisher
    • Department of KinesiologyAuburn University
  • J. L. Sartin
    • Department of Anatomy, Physiology, and PharmacologyCollege of Veterinary Medicine, Auburn University
  • T. H. Elsasser
    • Bovine Functional Genomics Laboratory, Agricultural Research ServiceU.S. Department of Agriculture
  • G. Wu
    • Cardiovascular Research Institute, Department of Systems Biology and Translational MedicineTexas A&M Health Science Center
    • Department of Animal ScienceTexas A&M University
  • W. Cowan
    • Department of Health and Physical EducationAthens State University
  • D. D. Pascoe
    • Department of KinesiologyAuburn University
Original Article

DOI: 10.1007/s00726-011-0837-y

Cite this article as:
Foster, E.B., Fisher, G., Sartin, J.L. et al. Amino Acids (2012) 42: 1405. doi:10.1007/s00726-011-0837-y


This investigation sought to examine the contributions of exercise and nutrient replenishment on in vivo regulation of the insulin-like growth factor-I (IGF-I) axis components. Eight college-aged males completed three high-intensity interval training (HIIT) protocols followed by three post-exercise nutritional protocols: (1) placebo (EX); (2) carbohydrate only (CHO); and (3) essential amino acid/carbohydrate (EAA/CHO). Samples were analyzed for growth hormone (GH), free IGF-I, IGFBP-1, IGFBP-2, insulin, hematocrit, hemoglobin, serum leucine, matrix metalloproteinase-9 (MMP-9) proteolytic activity, and presence of IGFBP-3 protease activity. No evidence for IGFBP-3 proteolysis was observed. Significant increases in [free IGF-I] and [leucine] were observed in the EAA/CHO group only. Significant differences were noted in [IGFBP-1] and [IGFBP-2] across conditions. Significant increases in [GH] and MMP-9 activity were observed in all groups. These results indicate that post-exercise macronutrient ratio is a determinant of [free IGF-I], [IGFBP-1 and -2] and may play a role in modulating the IGF-I axis in vivo.



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© Springer-Verlag 2011