| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Surgery2 Department of Physiology, Royal Free and University College Medical School, Rowland Hill Street, London NW3 2PF, UK,3 Sports Medicine Research Unit, Bispebjerg Hospital, Copenhagen Muscle Research Centre, Copenhagen, Denmark4 Department of Molecular Muscle Biology, Copenhagen Muscle Research Centre, Copenhagen, Denmark
The expression of two isoforms of insulin-like growth factor-I (IGF-I): mechano growth factor (MGF) and IGF-IEa were studied in muscle in response to growth hormone (GH) administration with and without resistance training in healthy elderly men. A third isoform, IGF-IEb was also investigated in response to resistance training only. The subjects (age 74 ± 1 years, mean ±S.E.M) were assigned to either resistance training with placebo, resistance training combined with GH administration or GH administration alone. Real-time quantitative RT-PCR was used to determine mRNA levels in biopsies from the vastus lateralis muscle at baseline, after 5 and 12 weeks in the three groups. GH administration did not change MGF mRNA at 5 weeks, but significantly increased IGF-IEa mRNA (237%). After 12 weeks, MGF mRNA was significantly increased (80%) compared to baseline. Five weeks of resistance training significantly increased the mRNA expression of MGF (163%), IGF-IEa (68%) and IGF-IEb (75%). No further changes were observed after 12 weeks. However, after 5 weeks of training combined with GH treatment, MGF mRNA increased significantly (456%) and IGF-IEa mRNA by (167%). No further significant changes were noted at 12 weeks. The data suggest that when mechanical loading in the form of resistance training is combined with GH, MGF mRNA levels are enhanced. This may reflect an overall up-regulation of transcription of the IGF-I gene prior to splicing.
(Received 21 July 2003;
accepted after revision 14 October 2003;
first published online 18 October 2003)
Corresponding author M. Hameed: Department of Surgery, Royal Free and University College Medical School, Rowland Hill Street, London NW3 2PF, UK. Email: m.hameed{at}rfc.ucl.ac.uk
This article has been cited by other articles:
|
|
 |
|
  B. D. Hand, M. C. Kostek, R. E. Ferrell, M. J. Delmonico, L. W. Douglass, S. M. Roth, J. M. Hagberg, and B. F. Hurley Influence of promoter region variants of insulin-like growth factor pathway genes on the strength-training response of muscle phenotypes in older adults J Appl Physiol, November 1, 2007; 103(5): 1678 - 1687. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. I. Lewis, M. Fournier, T. W. Storer, S. Bhasin, J. Porszasz, S.-G. Ren, X. Da, and R. Casaburi Skeletal muscle adaptations to testosterone and resistance training in men with COPD J Appl Physiol, October 1, 2007; 103(4): 1299 - 1310. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. D. R. Harridge Plasticity of human skeletal muscle: gene expression to in vivo function Exp Physiol, September 1, 2007; 92(5): 783 - 797. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. Bamman, J. K. Petrella, J.-s. Kim, D. L. Mayhew, and J. M. Cross Cluster analysis tests the importance of myogenic gene expression during myofiber hypertrophy in humans J Appl Physiol, June 1, 2007; 102(6): 2232 - 2239. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Heinemeier, J. L. Olesen, P. Schjerling, F. Haddad, H. Langberg, K. M. Baldwin, and M. Kjaer Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types J Appl Physiol, February 1, 2007; 102(2): 573 - 581. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Liu, D. M. Bravata, I. Olkin, S. Nayak, B. Roberts, A. M. Garber, and A. R. Hoffman Systematic Review: The Safety and Efficacy of Growth Hormone in the Healthy Elderly Ann Intern Med, January 16, 2007; 146(2): 104 - 115. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Kvorning, M. Andersen, K. Brixen, P. Schjerling, C. Suetta, and K. Madsen Suppression of testosterone does not blunt mRNA expression of myoD, myogenin, IGF, myostatin or androgen receptor post strength training in humans J. Physiol., January 15, 2007; 578(2): 579 - 593. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A M Solomon and P M G Bouloux Modifying muscle mass - the endocrine perspective. J. Endocrinol., November 1, 2006; 191(2): 349 - 360. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G Goldspink and P Jakeman Research on mechano growth factor: its potential for optimising physical training as well as misuse in doping * Commentary Br. J. Sports Med., November 1, 2005; 39(11): 787 - 788. [Full Text] [PDF]
|
|
|
|
 |
|
 G. Goldspink Mechanical Signals, IGF-I Gene Splicing, and Muscle Adaptation Physiology, August 1, 2005; 20(4): 232 - 238. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-s. Kim, J. M. Cross, and M. M. Bamman Impact of resistance loading on myostatin expression and cell cycle regulation in young and older men and women Am J Physiol Endocrinol Metab, June 1, 2005; 288(6): E1110 - E1119. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Iida, E. Itoh, D.-S. Kim, J. P del Rincon, K. T Coschigano, J. J Kopchick, and M. O Thorner Muscle mechano growth factor is preferentially induced by growth hormone in growth hormone-deficient lit/lit mice J. Physiol., October 15, 2004; 560(2): 341 - 349. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. GOLDSPINK Age-Related Muscle Loss and Progressive Dysfunction in Mechanosensitive Growth Factor Signaling Ann. N.Y. Acad. Sci., June 1, 2004; 1019(1): 294 - 298. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
