CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids
Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.ORCID iD: 0000-0003-2921-833x
Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.ORCID iD: 0000-0001-5885-2378
Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.ORCID iD: 0000-0003-3747-0148
Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.ORCID iD: 0000-0003-1942-2919
Show others and affiliations
2019 (English)In: Frontiers in nutrition, ISSN 2296-861X, Vol. 6, article id 96Article in journal (Refereed) Published
Abstract [en]

Human muscles contain a mixture of type I and type II fibers with different contractile and metabolic properties. Little is presently known about the effect of anabolic stimuli, in particular nutrition, on the molecular responses of these different fiber types. Here, we examine the effect of resistance exercise in combination with intake of essential amino acids (EAA) on mTORC1 signaling in individual type I and type II human muscle fibers. Five strength-trained men performed two sessions of heavy leg press exercise. During exercise and recovery, the subjects ingested an aqueous solution of EAA (290 mg/kg) or flavored water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibers dissected out and weighed (range 0.95-8.1 mu g). The fibers were homogenized individually and identified as type I or II by incubation with antibodies against the different isoforms of myosin. They were also analyzed for both the levels of protein as well as phosphorylation of proteins in the mTORC1 pathway using Western blotting. The levels of the S6K1 and eEF2 proteins were similar to 50% higher in type II than in type I fibers (P < 0.05), but no difference was found between fiber types with respect to the level of mTOR protein. Resistance exercise led to non-significant increases (2-3-fold) in mTOR and S6K1 phosphorylation as well as a 50% decrease (P < 0.05) in eEF2 phosphorylation in both fiber types. Intake of EAA caused a 2 and 6-fold higher (P < 0.05) elevation of mTOR and S6K1 phosphorylation, respectively, in both type I and type II fibers compared to placebo, with no effect on phosphorylation of eEF2. In conclusion, protein levels of S6K1 and eEF2 were significantly higher in type II than type I fibers suggesting higher capacity of the mTOR pathway in type II fibers. Ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and S6K1 in both fiber types, but with considerable variation between single fibers of both types.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019. Vol. 6, article id 96
Keywords [en]
muscle fiber type, protein expression, S6K1, single muscle fiber, EAA
National Category
Nutrition and Dietetics
Research subject
Medicine/Technology
Identifiers
URN: urn:nbn:se:gih:diva-5807DOI: 10.3389/fnut.2019.00096ISI: 000472610200002PubMedID: 31294029OAI: oai:DiVA.org:gih-5807DiVA, id: diva2:1342859
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14

Open Access in DiVA

fulltext(2488 kB)12 downloads
File information
File name FULLTEXT01.pdfFile size 2488 kBChecksum SHA-512
60df0c509fed11a395db62ad002953e7f1311ecf9b2df6fd295cbb34719fb2cc08d1eb6107d6a4d3f525d4cc0f9912ec7f48e66427f27f1e80c07725e68ff282
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMed

Authority records BETA

Edman, SebastianSöderlund, KarinMoberg, MarcusApro, WilliamBlomstrand, Eva

Search in DiVA

By author/editor
Edman, SebastianSöderlund, KarinMoberg, MarcusApro, WilliamBlomstrand, Eva
By organisation
Eva Blomstrand's research groupÅstrand Laboratory of Work Physiology
Nutrition and Dietetics

Search outside of DiVA

GoogleGoogle Scholar
Total: 12 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 94 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf