Growth Hormone Molecular Heterogeneity and Exercise

In Brief NINDL, B. C., W. J. KRAEMER, J. O. MARX, A. P. TUCKOW, and W. C. HYMER. Growth hormone molecular heterogeneity and exercise. Exerc. Sport Sci. Rev., Vol. 31, No. 4, pp. 161–166, 2003. There are more than 100 molecular isoforms of circulating growth hormone (GH), but the traditional measurement approach in the exercise literature has only focused on the main isoform ( i.e., 22 kDa). New assay methodologies now can assess various GH isoforms. The current data suggest that exercise results in the preferential release of GH isoforms with extended half-lives, thereby sustaining biological actions. Exercise induces alterations in the molecular isoforms of growth hormone (GH), which potentially enhances the biological activity of GH.