title: Ribosome biogenesis adaptation in resistance training-induced human skeletal muscle hypertrophy.
abstract: Resistance training (RT) has the capacity to increase skeletal muscle mass, which is due in part to transient increases in the rate of muscle protein synthesis during postexercise recovery. The role of ribosome biogenesis in supporting the increased muscle protein synthetic demands is not known. This study examined the effect of both a single acute bout of resistance exercise (RE) and a chronic RT program on the muscle ribosome biogenesis response. Fourteen healthy young men performed a single bout of RE both before and after 8 wk of chronic RT. Muscle cross-sectional area was increased by 6 ± 4.5% in response to 8 wk of RT. Acute RE-induced activation of the ERK and mTOR pathways were similar before and after RT, as assessed by phosphorylation of ERK, MNK1, p70S6K, and S6 ribosomal protein 1 h postexercise. Phosphorylation of TIF-IA was also similarly elevated following both RE sessions. Cyclin D1 protein levels, which appeared to be regulated at the translational rather than transcriptional level, were acutely increased after RE. UBF was the only protein found to be highly phosphorylated at rest after 8 wk of training. Also, muscle levels of the rRNAs, including the precursor 45S and the mature transcripts (28S, 18S, and 5.8S), were increased in response to RT. We propose that ribosome biogenesis is an important yet overlooked event in RE-induced muscle hypertrophy that warrants further investigation.
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand;
authors.forename: Vandre C
authors.initials: VC
authors.lastname: Figueiredo
authors.affiliation: Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia; and.
authors.forename: Marissa K
authors.initials: MK
authors.lastname: Caldow
authors.affiliation: Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Vivien
authors.initials: V
authors.lastname: Massie
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand;
authors.forename: James F
authors.initials: JF
authors.lastname: Markworth
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand; d.cameron-smith@auckland.ac.nz.
authors.forename: David
authors.initials: D
authors.lastname: Cameron-Smith
authors.affiliation: Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Blazevich
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D004734:Energy Metabolism / Q000502:physiology; D006801:Humans; D006984:Hypertrophy; D008297:Male; D053858:Metabolic Networks and Pathways; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D010442:Peptide Chain Initiation, Translational / Q000502:physiology; D055070:Resistance Training; D012146:Rest / Q000502:physiology; D012270:Ribosomes / Q000502:physiology*; D055815:Young Adult
keywords: cyclin D1; ribosomal RNA; transcription initiation factor 1A; upstream binding protein