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Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle.
Am J Physiol Endocrinol Metab. 2010 Feb; 298(2):E257-69.AJ

Abstract

Exercise stimulates muscle protein fractional synthesis rate (FSR), but the importance of contractile intensity and whether it interplays with feeding is not understood. This was investigated following two distinct resistance exercise (RE) contraction intensities using an intrasubject design in the fasted (n = 10) and fed (n = 10) states. RE consisted of 10 sets of knee extensions. One leg worked against light load (LL) at 16% of one-repetition maximum (1RM), the other leg against heavy load (HL) at 70% 1RM, with intensities equalized for total lifted load. Males were infused with [(13)C]leucine, and vastus lateralis biopsies were obtained bilaterally at rest as well as 0.5, 3, and 5.5 h after RE. Western blots were run on muscle lysates and phosphospecific antibodies used to detect phosphorylation status of targets involved in regulation of FSR. The intramuscular collagen FSR was evenly increased following LL- and HL-RE and was not affected by feeding. Myofibrillar FSR was unaffected by LL-RE, whereas HL-RE resulted in a delayed improvement (0.14 +/- 0.02%/h, P < 0.05). Myofibrillar FSR was increased at rest by feeding (P < 0.05) and remained elevated late in the postexercise period compared with the fasting condition. The Rp-s6k-4E-binding protein-1 (BP1) and the mitogen-activated protein kinase (MAPk) pathways were activated by the HL intensity and were suggested to be responsible for regulating myofibrillar FSR in response to adequate contractile activity. Feeding predominantly affected Rp-s6k and eukaryotic elongation factor 2 phosphorylations in correspondence with the observed changes in myofibrillar FSR, whereas 4E-BP1 remained to respond only to the HL contraction intensity. Thus the study design allows us to conclude that the MAPk- and mammalian target of rapamycin-dependent signaling responds to contractile activity, whereas elongation mainly was found to respond to feeding. Furthermore, although functionally linked, the contractile and the supportive matrix structures upregulate their protein synthesis rate quite differently in response to feeding and contractile activity and intensity.

Authors+Show Affiliations

Institute of Sports Medicine, Bispebjerg Hospital and Center of Healthy Aging, University of Copenhagen, Copenhagen, Denmark. l.holm.isotope@gmail.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19903866

Citation

Holm, Lars, et al. "Contraction Intensity and Feeding Affect Collagen and Myofibrillar Protein Synthesis Rates Differently in Human Skeletal Muscle." American Journal of Physiology. Endocrinology and Metabolism, vol. 298, no. 2, 2010, pp. E257-69.
Holm L, van Hall G, Rose AJ, et al. Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle. Am J Physiol Endocrinol Metab. 2010;298(2):E257-69.
Holm, L., van Hall, G., Rose, A. J., Miller, B. F., Doessing, S., Richter, E. A., & Kjaer, M. (2010). Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle. American Journal of Physiology. Endocrinology and Metabolism, 298(2), E257-69. https://doi.org/10.1152/ajpendo.00609.2009
Holm L, et al. Contraction Intensity and Feeding Affect Collagen and Myofibrillar Protein Synthesis Rates Differently in Human Skeletal Muscle. Am J Physiol Endocrinol Metab. 2010;298(2):E257-69. PubMed PMID: 19903866.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle. AU - Holm,Lars, AU - van Hall,Gerrit, AU - Rose,Adam J, AU - Miller,Benjamin F, AU - Doessing,Simon, AU - Richter,Erik A, AU - Kjaer,Michael, Y1 - 2009/11/10/ PY - 2009/11/12/entrez PY - 2009/11/12/pubmed PY - 2010/9/2/medline SP - E257 EP - 69 JF - American journal of physiology. Endocrinology and metabolism JO - Am J Physiol Endocrinol Metab VL - 298 IS - 2 N2 - Exercise stimulates muscle protein fractional synthesis rate (FSR), but the importance of contractile intensity and whether it interplays with feeding is not understood. This was investigated following two distinct resistance exercise (RE) contraction intensities using an intrasubject design in the fasted (n = 10) and fed (n = 10) states. RE consisted of 10 sets of knee extensions. One leg worked against light load (LL) at 16% of one-repetition maximum (1RM), the other leg against heavy load (HL) at 70% 1RM, with intensities equalized for total lifted load. Males were infused with [(13)C]leucine, and vastus lateralis biopsies were obtained bilaterally at rest as well as 0.5, 3, and 5.5 h after RE. Western blots were run on muscle lysates and phosphospecific antibodies used to detect phosphorylation status of targets involved in regulation of FSR. The intramuscular collagen FSR was evenly increased following LL- and HL-RE and was not affected by feeding. Myofibrillar FSR was unaffected by LL-RE, whereas HL-RE resulted in a delayed improvement (0.14 +/- 0.02%/h, P < 0.05). Myofibrillar FSR was increased at rest by feeding (P < 0.05) and remained elevated late in the postexercise period compared with the fasting condition. The Rp-s6k-4E-binding protein-1 (BP1) and the mitogen-activated protein kinase (MAPk) pathways were activated by the HL intensity and were suggested to be responsible for regulating myofibrillar FSR in response to adequate contractile activity. Feeding predominantly affected Rp-s6k and eukaryotic elongation factor 2 phosphorylations in correspondence with the observed changes in myofibrillar FSR, whereas 4E-BP1 remained to respond only to the HL contraction intensity. Thus the study design allows us to conclude that the MAPk- and mammalian target of rapamycin-dependent signaling responds to contractile activity, whereas elongation mainly was found to respond to feeding. Furthermore, although functionally linked, the contractile and the supportive matrix structures upregulate their protein synthesis rate quite differently in response to feeding and contractile activity and intensity. SN - 1522-1555 UR - https://www.unboundmedicine.com/medline/citation/19903866/Contraction_intensity_and_feeding_affect_collagen_and_myofibrillar_protein_synthesis_rates_differently_in_human_skeletal_muscle_ L2 - https://journals.physiology.org/doi/10.1152/ajpendo.00609.2009?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -