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Tannerstedt, Jörgen
Alternative names
Publications (3 of 3) Show all publications
Mascher, H., Tannerstedt, J., Brink-Elfegoun, T., Ekblom, B., Gustafsson, T. & Blomstrand, E. (2008). Repeated resistance exercise training induces different changes in mRNA expression of MAFbx and MuRF-1 in human skeletal muscle.. American Journal of Physiology. Endocrinology and Metabolism, 294(1), E43-51
Open this publication in new window or tab >>Repeated resistance exercise training induces different changes in mRNA expression of MAFbx and MuRF-1 in human skeletal muscle.
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2008 (English)In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 294, no 1, p. E43-51Article in journal (Refereed) Published
Abstract [en]

The gain in muscle mass as a result of resistance training is dependent on changes in both anabolic and catabolic reactions. A frequency of two to three exercise sessions per week is considered optimal for muscle gain in untrained individuals. Our hypothesis was that a second exercise session would enlarge the anabolic response and/or decrease the catabolic response. Eight male subjects performed resistance exercise on two occasions separated by 2 days. Muscle biopsies were taken from the vastus lateralis before and 15 min, 1 h, and 2 h after exercise. Exercise led to severalfold increases in phosphorylation of mTOR at Ser2448, p70 S6 kinase (p70S6k) at Ser424/Thr421 and Thr389, and ribosomal protein S6, which persisted for up to 2 h of recovery on both occasions. There was a tendency toward a larger effect of the second exercise on p70S6k and S6, but the difference did not reach statistical significance. The mRNA expression of MuRF-1, which increased after exercise, was 30% lower after the second exercise session than after the first one. MAFbx expression was not altered after exercise but downregulated 30% 48 h later, whereas myostatin expression was reduced by 45% after the first exercise and remained low until after the second exercise session. The results indicate that 1) changes in expression of genes involved in protein degradation are attenuated as a response to repetitive resistance training with minor additional increases in enzymes regulating protein synthesis and 2) the two ubiquitin ligases, MuRF-1 and MAFbx, are differently affected by the exercise as well as by repeated exercise.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:gih:diva-960 (URN)10.1152/ajpendo.00504.2007 (DOI)17971512 (PubMedID)
Available from: 2009-09-24 Created: 2009-09-21 Last updated: 2017-12-13Bibliographically approved
Eliasson, J., Elfegoun, T., Nilsson, J., Köhnke, R., Ekblom, B. & Blomstrand, E. (2006). Maximal lengthening contractions increase p70 S6 kinase phosphorylation in human skeletal muscle in the absence of nutritional supply.. American Journal of Physiology. Endocrinology and Metabolism, 291(6), 1197-1205
Open this publication in new window or tab >>Maximal lengthening contractions increase p70 S6 kinase phosphorylation in human skeletal muscle in the absence of nutritional supply.
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2006 (English)In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 291, no 6, p. 1197-1205Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to compare the training stimuli of eccentric (lengthening) and concentric (shortening) contractions regarding the effect on signaling enzymes involved in protein synthesis. Ten male subjects performed 4 x 6 maximal eccentric contractions on one leg followed by 4 x 6 maximal concentric contractions on the other. Six additional subjects performed the same protocol, but with maximal concentric and submaximal eccentric exercise of equal force to that of the maximal concentric contractions. Muscle biopsy samples were taken from the vastus lateralis before, immediately after, and 1 and 2 h after exercise in both legs. The average peak force produced during the maximal eccentric exercise was 31% higher than during the maximal concentric exercise, 2,490 (+/-100) vs. 1,894 (+/-108) N (P < 0.05). The maximal eccentric contractions led to two- to eightfold increases in the phosphorylation of p70 S6 kinase (p70(S6k)) and the ribosomal protein S6 that persisted for 2 h into recovery but no significant changes in phosphorylation of Akt or mammalian target of rapamycin (mTOR). Maximal concentric and submaximal eccentric contractions did not induce any significant changes in Akt, mTOR, p70(S6k), or S6 phosphorylation up to 2 h after the exercise. The results indicate that one session of maximal eccentric contractions activates p70(S6k) in human muscle via an Akt-independent pathway and suggest that maximal eccentric contractions are more effective than maximal concentric contractions in stimulating protein synthesis in the absence of a nutritional intake, an effect that may be mediated through a combination of greater tension and stretching of the muscle.

Keywords
mode of contraction; protein synthesis; translation initiation
National Category
Physiology
Identifiers
urn:nbn:se:gih:diva-175 (URN)10.1152/ajpendo.00141.2006 (DOI)16835402 (PubMedID)
Available from: 2007-03-30 Created: 2007-03-30 Last updated: 2018-01-12Bibliographically approved
Mascher, H., Tannerstedt, J. & Blomstrand, E. (2006). Nya aspekter på aminosyrors roll i den muskulära anpassningen till träning. Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, 15(3), 56-60
Open this publication in new window or tab >>Nya aspekter på aminosyrors roll i den muskulära anpassningen till träning
2006 (Swedish)In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 15, no 3, p. 56-60Article in journal (Other academic) Published
Abstract [sv]

Sammanfattningsvis kan sägas att tillgängligheten av protein/aminosyror är nödvändig för den muskulära anpassningen till träning vid både styrke- och uthållighetsträning. Betydligt fler studier har undersökt effekterna på styrketräning, men vid båda typer av träning är dock kunskaperna om de bakomliggande mekanismerna ännu så länge små. Genom den omfattande forskning som pågår inom området kommer med all säkerhet de molekylära och cellulära förändringar som sker i samband med träning att kartläggas inom en relativt snar framtid. Därmed öppnas nya möjligheter att förbättra och optimera träningen, t.ex. genom kombination av olika typer av aktiviteter (uthållighet och styrketräning). Denna kunskap är också avgörande för att förstå och eventuellt kunna påverka träningseffekten genom förändringar i nutritionens sammansättning.

Keywords
aminosyror, styrketräning, uthållighetsträning, proteinsyntes
National Category
Medical Bioscience
Identifiers
urn:nbn:se:gih:diva-304 (URN)
Available from: 2007-10-26 Created: 2007-10-26 Last updated: 2017-12-06
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