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Study · Not a test of the peptide alone · 2005

6 results

Testosterone supplementation in healthy older men drives GH and IGF-I secretion without potentiating peptidyl secretagogue efficacy.

Veldhuis JD, Keenan DM, Mielke K, Miles JM, Bowers CY

European journal of endocrinology1 Oct 2005Cited by 25 (Europe PMC)

PMID16189179 (opens in a new tab)DOI10.1530/eje.1.02001 (opens in a new tab)PepBankPUB-16189179
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 study6

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

Studies that did not test the peptide alone6

In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking GHRP-2.

  1. 01HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, testosterone increased fasting GH concentrations versus placebo.

    In plain wordsIn older men, testosterone raised fasting growth hormone levels compared with placebo.

    Peptide
    GHRP-2
    Outcome
    IncreaseFasting GH concentration with testosterone
    Study

    n = 7

    Comparator
    Placebo
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Statistical contrasts revealed that administration of testosterone compared with placebo in seven men aged 60-77 years increased fasting concentrations of GH (P < 0.01) and IGF-I (P = 0.003), and basal (P < 0.005) and pulsatile (P < 0.01) GH secretion.
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

  2. 02HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, testosterone increased fasting IGF-I concentrations versus placebo.

    In plain wordsIn older men, testosterone raised fasting IGF-I levels compared with placebo.

    Peptide
    GHRP-2
    Outcome
    IncreaseFasting IGF-I concentration with testosterone
    Study

    n = 7

    Comparator
    Placebo
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Statistical contrasts revealed that administration of testosterone compared with placebo in seven men aged 60-77 years increased fasting concentrations of GH (P < 0.01) and IGF-I (P = 0.003), and basal (P < 0.005) and pulsatile (P < 0.01) GH secretion.
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

  3. 03HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, testosterone increased basal GH secretion versus placebo.

    In plain wordsIn older men, testosterone raised baseline growth hormone release compared with placebo.

    Peptide
    GHRP-2
    Outcome
    IncreaseBasal GH secretion with testosterone
    Study

    n = 7

    Comparator
    Placebo
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Statistical contrasts revealed that administration of testosterone compared with placebo in seven men aged 60-77 years increased fasting concentrations of GH (P < 0.01) and IGF-I (P = 0.003), and basal (P < 0.005) and pulsatile (P < 0.01) GH secretion.
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

  4. 04HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, testosterone increased pulsatile GH secretion versus placebo.

    In plain wordsIn older men, testosterone raised pulsed growth hormone release compared with placebo.

    Peptide
    GHRP-2
    Outcome
    IncreasePulsatile GH secretion with testosterone
    Study

    n = 7

    Comparator
    Placebo
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Statistical contrasts revealed that administration of testosterone compared with placebo in seven men aged 60-77 years increased fasting concentrations of GH (P < 0.01) and IGF-I (P = 0.003), and basal (P < 0.005) and pulsatile (P < 0.01) GH secretion.
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

  5. 05HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, testosterone did not alter the absolute value or rank order of secretagogue efficacy, including l-arginine/GHRP‑2 and GHRH/GHRP‑2.

    In plain wordsIn older men, testosterone did not change how strongly GHRP‑2 combinations stimulated growth hormone.

    Peptide
    GHRP-2
    Outcome
    No significant changeSecretagogue efficacy after testosterone
    Study

    n = 7

    Comparator
    Placebo
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Testosterone did not alter the absolute value or rank order of secretagogue efficacy: l-arginine/GHRP-2 (23-fold effect over saline) = GHRH/GHRP-2 (20-fold) > l-arginine/GHRH (7.5-fold).
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

  6. 06HumanNot a test of GHRP-2 aloneRandomized controlled trialEfficacy outcome

    In healthy older men, each secretagogue pair, including those with GHRP‑2, accelerated initial GH secretion within a burst.

    In plain wordsIn older men, each pair of GH stimulants, including pairs with GHRP‑2, sped up the start of growth hormone release.

    Peptide
    GHRP-2
    Outcome
    IncreaseSpeed of initial GH secretion within a burst with secretagogue pairs
    Study

    n = 7

    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Waveform reconstruction indicated that each stimulus pair accelerated initial GH secretion within a burst (P < 0.01).
    2 context sentences
    Summary · context
    Randomized double-blind crossover design of placebo versus testosterone administration in healthy older men.
    Summary · context
    Deconvolution analysis was used to estimate basal GH secretion and the mass (integral) and waveform (time-shape) of GH secretory bursts.

    In this study, GHRP-2 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-2.

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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