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Study · Animal study (in vivo) · rat · 1998

5 results

The nonpeptide growth hormone secretagogue, MK-0677, activates hypothalamic arcuate nucleus neurons in vivo.

Bailey AR, Smith RG, Leng G

Journal of neuroendocrinology1 Feb 1998Cited by 16 (Europe PMC)

PMID9535057 (opens in a new tab)DOI10.1046/j.1365-2826.1998.00176.x (opens in a new tab)PepBankPUB-09535057
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 study5

3 results from studies that gave the peptide. No result from this study comes from people.

  1. 01AnimalAnimal study (in vivo)Mechanism

    In male rats, central and systemic MK-0677 induced Fos-like immunoreactivity in the arcuate nucleus.

    In plain wordsIn rats, central and systemic MK-0677 activated arcuate neurons.

    Peptide
    MK-677 (ibutamoren)
    Outcome
    IncreaseArcuate Fos immunoreactivity
    Study

    ratn: not reported in source

    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated · central and systemic injectionAs given in this study (rat).

    Source sentences

    Summary
    In conscious male rats, both central and systemic injection of MK-0677 induced fos-like immunoreactivity specifically within the arcuate nucleus indicating selective neuronal activation of neurons within this region.
    1 context sentence
    Summary · context
    Therefore, in the present study, we have employed both immunocytochemical and in vivo electrophysiological techniques to examine the effects of MK-0677 within the hypothalamic arcuate nucleus of the male rat.
  2. 02AnimalAnimal study (in vivo)Mechanism

    In rats, systemic GHRP‑6 induced Fos-like immunoreactivity in more lateral arcuate regions than MK-0677.

    In plain wordsIn rats, GHRP‑6 activated more lateral arcuate regions than MK-0677.

    Peptide
    GHRP-6
    Outcome
    IncreaseLateral arcuate Fos immunoreactivity
    Study

    ratn: not reported in source

    Comparator
    MK-0677
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated · systemic injectionAs given in this study (rat).

    Source sentences

    Summary
    MK-0677 induced-activation was generally confined close to the wall of the third ventricle, whereas systemic injection of the peptide secretagogue, GHRP-6, also induced fos-like immunoreactivity in more lateral regions of the nucleus.
    1 context sentence
    Summary · context
    Therefore, in the present study, we have employed both immunocytochemical and in vivo electrophysiological techniques to examine the effects of MK-0677 within the hypothalamic arcuate nucleus of the male rat.
  3. 03AnimalAnimal study (in vivo)Mechanism

    In anaesthetized rats, MK-0677 increased neuroendocrine arcuate neuron electrical activity.

    In plain wordsIn rats, MK-0677 increased electrical activity in neuroendocrine arcuate neurons.

    Peptide
    MK-677 (ibutamoren)
    Outcome
    IncreaseNeuroendocrine arcuate electrical activity
    Study

    ratn: not reported in source

    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    Dose not stated · intravenousAs given in this study (rat).

    Source sentences

    Summary
    In urethane anaesthetized rats, intravenous injection of MK-0677 increased the electrical activity of a population of antidromically identified (i.e. neuroendocrine) arcuate neurons with a similar electrophysiological profile to cells excited by GHRP-6.
    1 context sentence
    Summary · context
    Therefore, in the present study, we have employed both immunocytochemical and in vivo electrophysiological techniques to examine the effects of MK-0677 within the hypothalamic arcuate nucleus of the male rat.

Studies that did not test the peptide alone2

In this study, MK-677 (ibutamoren) 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 MK-677 (ibutamoren).

  1. 04AnimalNot a test of MK-677 (ibutamoren) aloneAnimal study (in vivo)Mechanism

    In rats, subsequent somatostatin could attenuate electrical activity of arcuate neurons excited by MK-0677.

    In plain wordsIn rats, somatostatin could reduce activity in arcuate neurons excited by MK-0677.

    Peptide
    MK-677 (ibutamoren)
    Outcome
    DecreaseSomatostatin attenuation of neuronal excitation
    Study

    ratn: not reported in source

    Outcome group
    Receptor activity and mechanism · Nervous system and cognition

    Source sentences

    Summary
    The activity of neuroendocrine arcuate neurons excited by MK-0677 injection could be attenuated by a subsequent systemic injection of somatostatin.
    1 context sentence
    Summary · context
    Therefore, in the present study, we have employed both immunocytochemical and in vivo electrophysiological techniques to examine the effects of MK-0677 within the hypothalamic arcuate nucleus of the male rat.

    In this study, MK-677 (ibutamoren) 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 MK-677 (ibutamoren).

  2. 05AnimalNot a test of MK-677 (ibutamoren) aloneAnimal study (in vivo)Mechanism

    In rats, somatostatin did not alter activity in neuroendocrine neurons unaffected by MK-0677 or non-neuroendocrine neurons.

    In plain wordsIn rats, somatostatin did not alter activity in neurons unaffected by MK-0677 or non-neuroendocrine neurons.

    Peptide
    MK-677 (ibutamoren)
    Outcome
    No significant changeSomatostatin response in unaffected neurons
    Study

    ratn: not reported in source

    Outcome group
    Receptor activity and mechanism · Nervous system and cognition

    Source sentences

    Summary
    However, the activity of neuroendocrine arcuate neurons unaffected by MK-0677 injection and the activity of non-neuroendocrine arcuate neurons was unaltered by somatostatin injection.
    1 context sentence
    Summary · context
    Therefore, in the present study, we have employed both immunocytochemical and in vivo electrophysiological techniques to examine the effects of MK-0677 within the hypothalamic arcuate nucleus of the male rat.

    In this study, MK-677 (ibutamoren) 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 MK-677 (ibutamoren).

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 3Current

    14 Oct 2026, 05:02 UTC

    Study results updated

  2. Version 2

    14 Oct 2026, 01:46 UTC

    Study data updated · source update from Europe PMC

  3. Version 1

    9 Oct 2026, 03:13 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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