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Study · Measured the body's own peptide · 2006

3 results

Efficacy of myonuclear addition may explain differential myofiber growth among resistance-trained young and older men and women.

Petrella JK, Kim JS, Cross JM, Kosek DJ, Bamman MM

American journal of physiology. Endocrinology and metabolism13 Jun 2006Cited by 273 (Europe PMC)

PMID16772322 (opens in a new tab)DOI10.1152/ajpendo.00190.2006 (opens in a new tab)PepBankPUB-16772322
Publisher pagePubMedAsk about this study
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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study3

No result from this study comes from a test of the peptide.

Natural levels measured3

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

  1. 01HumanEndogenous levelObservational studyMechanism

    In young adults, muscle MGF mRNA rose 81% after a single bout of resistance exercise.

    In plain wordsIn young adults, the body's own muscle MGF messenger RNA rose after one bout of resistance exercise.

    Peptide
    MGF / PEG-MGF
    Outcome
    IncreaseMuscle MGF mRNA after one resistance bout, young adults
    Study

    n = 26

    Comparator
    Baseline
    Outcome group
    Exercise and physical function · Musculoskeletal

    Measurements

    MGF mRNA change
    81%
    young adults, after one bout

    Source sentences

    Summary
    MGF mRNA increased only in young after one bout (81%) and by 16 wk (85%) (P < 0.001).
    3 context sentences
    Summary · context
    Twenty-six young (27.0 +/- 1 yr, 50% women) and 26 older (63.7 +/- 1 yr, 50% women) adults completed 16 wk of knee extensor resistance training.
    Summary · context
    Vastus lateralis biopsies were obtained at baseline, 24 h after one bout, and after 16 wk.
    Summary · context
    Muscle transcript levels of IGF-I and mechanogrowth factor (MGF) were determined by RT-PCR.

    This result measures the body's own MGF / PEG-MGF. Nobody was given the peptide. It is not evidence about taking it.

  2. 02HumanEndogenous levelObservational studyMechanism

    In young adults, muscle MGF mRNA was 85% higher after 16 weeks of resistance training.

    In plain wordsIn young adults, the body's own muscle MGF messenger RNA was higher after 16 weeks of resistance training.

    Peptide
    MGF / PEG-MGF
    Outcome
    IncreaseMuscle MGF mRNA after 16 weeks of resistance training, young adults
    Study

    n = 26

    Comparator
    Baseline
    Outcome group
    Exercise and physical function · Musculoskeletal

    Measurements

    MGF mRNA change
    85%
    young adults, at 16 weeks

    Source sentences

    Summary
    MGF mRNA increased only in young after one bout (81%) and by 16 wk (85%) (P < 0.001).
    3 context sentences
    Summary · context
    Twenty-six young (27.0 +/- 1 yr, 50% women) and 26 older (63.7 +/- 1 yr, 50% women) adults completed 16 wk of knee extensor resistance training.
    Summary · context
    Vastus lateralis biopsies were obtained at baseline, 24 h after one bout, and after 16 wk.
    Summary · context
    Muscle transcript levels of IGF-I and mechanogrowth factor (MGF) were determined by RT-PCR.

    This result measures the body's own MGF / PEG-MGF. Nobody was given the peptide. It is not evidence about taking it.

  3. 03HumanEndogenous levelObservational studyMechanism

    In older adults, muscle MGF mRNA did not increase after one resistance bout or after 16 weeks of resistance training, while it increased in young adults.

    In plain wordsIn older adults, the body's own muscle MGF messenger RNA did not rise after resistance exercise.

    Peptide
    MGF / PEG-MGF
    Outcome
    No significant changeMuscle MGF mRNA after resistance exercise, older adults
    Study

    n = 26

    Comparator
    Baseline
    Outcome group
    Exercise and physical function · Musculoskeletal

    Source sentences

    Summary
    MGF mRNA increased only in young after one bout (81%) and by 16 wk (85%) (P < 0.001).
    3 context sentences
    Summary · context
    Twenty-six young (27.0 +/- 1 yr, 50% women) and 26 older (63.7 +/- 1 yr, 50% women) adults completed 16 wk of knee extensor resistance training.
    Summary · context
    Vastus lateralis biopsies were obtained at baseline, 24 h after one bout, and after 16 wk.
    Summary · context
    Muscle transcript levels of IGF-I and mechanogrowth factor (MGF) were determined by RT-PCR.

    This result measures the body's own MGF / PEG-MGF. Nobody was given the peptide. It is not evidence about taking it.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    13 Oct 2026, 21:44 UTC

    Study results updated

  2. Version 1

    13 Oct 2026, 16:31 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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