TY - JOUR
T1 - The effect of recombinant human growth hormone and resistance training on IGF-I mRNA expression in the muscles of elderly men
AU - Hameed, M
AU - Lange, K H W
AU - Andersen, J L
AU - Schjerling, P
AU - Kjaer, M
AU - Harridge, S D R
AU - Goldspink, G
PY - 2004/2/15
Y1 - 2004/2/15
N2 - 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.
AB - 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.
KW - Aged
KW - Aged, 80 and over
KW - Aging/drug effects
KW - Analysis of Variance
KW - Double-Blind Method
KW - Exercise/physiology
KW - Gene Expression Regulation/drug effects
KW - Human Growth Hormone/pharmacology
KW - Humans
KW - Insulin-Like Growth Factor I/biosynthesis
KW - Male
KW - Muscle, Skeletal/drug effects
KW - Protein Isoforms/biosynthesis
KW - RNA, Messenger/biosynthesis
KW - Recombinant Proteins/pharmacology
KW - Weight Lifting/physiology
U2 - 10.1113/jphysiol.2003.051722
DO - 10.1113/jphysiol.2003.051722
M3 - Journal article
C2 - 14565994
SN - 0022-3751
VL - 555
SP - 231
EP - 240
JO - The Journal of Physiology
JF - The Journal of Physiology
IS - Pt 1
ER -