Document Detail

IGF-1 splice variant and IGF-1 peptide expression patterns in young and old human skeletal muscle prior to and following sequential exercise bouts.
MedLine Citation:
PMID:  20668872     Owner:  NLM     Status:  In-Process    
Genes and proteins involved in insulin-like growth factor (IGF)-1 signaling are thought to be differentially expressed in older versus younger mammalian skeletal muscle following acute exercise. The purpose of this study was to examine how multiple bouts of conventional resistance training meant to elicit hypertrophy affect the mRNA expression of IGF-1EA and IGF-1EC (MGF) as well as the expression of total IGF-1 peptides in human skeletal muscle. Ten younger (18-25 years) and 10 older (60-75 years) males completed three sequential workouts (M, W, F) consisting of nine sets of lower body exercises with ten repetitions per set at an intensity of 80% of one repetition maximum. Vastus lateralis muscle biopsies were collected prior to intervention (T1), 48 h following workout 1 (T2), 48 h following workout 2 (T3), and 24 h following workout 3 (T4). RT-PCR was performed to assess baseline and changes in MGF and IGF-IEA mRNA. Samples were also assayed for total muscle IGF-1 peptides using ELISA-based methods. There were no baseline differences in MGF or IGF-1EA mRNA expression and IGF-1 peptides between age groups. Interestingly, MGF expression increased at T2-T4 in the older group relative to baseline values (p < 0.05), albeit muscle IGF-1EA mRNA and IGF-1 peptides remained stably expressed throughout the intervention in both age groups. Repeated conventional exercise bouts resulted in a summative increase in MGF mRNA expression only in older individuals which is contrary to previous research examining this gene at different post-exercise time points, albeit the physiological consequences of these findings remain unknown.
Michael D Roberts; Vincent J Dalbo; Kyle L Sunderland; Chris N Poole; Scott E Hassell; Debra Bemben; Joel Cramer; Jeff Stout; Chad M Kerksick
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-07-29
Journal Detail:
Title:  European journal of applied physiology     Volume:  110     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-05     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  961-9     Citation Subset:  IM    
Health and Exercise Science Department, University of Oklahoma, Norman, OK 73019-6081, USA.
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