Acute regulation of IGF-I by alterations in post-exercise macronutrients. Academic Article uri icon


  • 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.

published proceedings

  • Amino Acids

author list (cited authors)

  • Foster, E. B., Fisher, G., Sartin, J. L., Elsasser, T. H., Wu, G., Cowan, W., & Pascoe, D. D.

citation count

  • 14

complete list of authors

  • Foster, EB||Fisher, G||Sartin, JL||Elsasser, TH||Wu, G||Cowan, W||Pascoe, DD

publication date

  • April 2012