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Study · Animal study (in vivo) · mouse · 2025

10 results

Intranasal Delivery of a Ghrelin Mimetic Engages the Brain Ghrelin Signaling System in Mice.

Poelman R, Le May MV, Schéle E, Stoltenborg I, Dickson SL

Endocrinology1 Feb 2025Cited by 3 (Europe PMC)

PMID39813130 (opens in a new tab)PMCIDPMC11795113 (opens in a new tab)DOI10.1210/endocr/bqae166 (opens in a new tab)PepBankPUB-39813130
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Summary

Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor (GHSR), promotes food intake and other feeding behaviors, and stimulates growth hormone (GH) release from the pituitary. Growth hormone secretagogues (GHS), such as GHRP-6 and MK-0677, are synthetic GHSR ligands that activate orexigenic neuropeptide Y neurons that coexpress agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus when administered systemically. Systemic GHRP-6 also stimulates GH release in humans and rats. Thus, GHS and ghrelin have therapeutic relevance in patients who could benefit from its orexigenic and/or GH-releasing effects. This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system. Effective compounds and doses were selected based on increased food intake after intranasal application in mice. Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope. We also assessed the effect of intranasal GHRP-6 on serum GH levels. Intranasal GHRP-6 increased food intake by increasing meal frequency and size. Fos expression in the arcuate nucleus was higher in GHRP-6-treated mice than in saline controls. When examining the neurochemical identity of c-fos-mRNA-expressing neurons, we found coexpression with 63.5 ± 1.9% Ghsr mRNA, 79 ± 6.8% Agrp mRNA, and 11.4 ± 2.5% Ghrh mRNA, demonstrating GHRP-6's ability to engage arcuate nucleus neurons involved in food intake and GH release. Additionally, intranasal GHRP-6 elevated GH serum levels. These findings suggest that intranasal GHRP-6, but not ghrelin or MK-0677, can engage the brain ghrelin signaling system.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study10

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

  1. 01AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intranasal GHRP‑6 increased food intake.

    In plain wordsIn mice, intranasal GHRP‑6 increased food intake.

    Peptide
    GHRP-6
    Outcome
    IncreaseFood intake
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Appetite and food intake · Metabolic and weight
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
    2 context sentences
    Summary · context
    Intranasal GHRP-6 increased food intake by increasing meal frequency and size.
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  2. 02AnimalAnimal study (in vivo)Safety outcome

    In mice, intranasal GHRP‑6 increased food intake without adverse effects.

    In plain wordsIn mice, intranasal GHRP‑6 increased food intake without adverse effects.

    Peptide
    GHRP-6
    Outcome
    Not applicableAdverse effects
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Adverse events · Whole body
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  3. 03AnimalAnimal study (in vivo)Efficacy outcome

    In mice tested with intranasal secretagogues, only GHRP-6, rather than MK-0677, increased food intake without adverse effects.

    In plain wordsIn mice, only GHRP-6, rather than MK-0677, increased food intake without adverse effects.

    Peptide
    MK-677 (ibutamoren)
    Outcome
    Direction not reportedFood intake without adverse effects
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Appetite and food intake · Metabolic and weight
    Studied dose
    Dose not stated · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  4. 04AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intranasal GHRP‑6 increased meal frequency.

    In plain wordsIn mice, intranasal GHRP‑6 increased meal frequency.

    Peptide
    GHRP-6
    Outcome
    IncreaseMeal frequency
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Appetite and food intake · Metabolic and weight
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Intranasal GHRP-6 increased food intake by increasing meal frequency and size.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  5. 05AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intranasal GHRP‑6 increased meal size.

    In plain wordsIn mice, intranasal GHRP‑6 increased meal size.

    Peptide
    GHRP-6
    Outcome
    IncreaseMeal size
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Appetite and food intake · Metabolic and weight
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Intranasal GHRP-6 increased food intake by increasing meal frequency and size.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  6. 06AnimalAnimal study (in vivo)Mechanism

    In mice, GHRP‑6 increased arcuate nucleus Fos expression versus saline controls.

    In plain wordsIn mice, GHRP‑6 increased arcuate nucleus Fos expression compared with saline controls.

    Peptide
    GHRP-6
    Outcome
    IncreaseArcuate nucleus Fos expression
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Comparator
    Saline controls
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Fos expression in the arcuate nucleus was higher in GHRP-6-treated mice than in saline controls.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  7. 07AnimalAnimal study (in vivo)Mechanism

    In mice treated with GHRP‑6, c-fos-mRNA-expressing neurons showed 63.5 ± 1.9% coexpression with Ghsr mRNA.

    In plain wordsIn mice treated with GHRP‑6, activated neurons showed Ghsr gene coexpression.

    Peptide
    GHRP-6
    Outcome
    Not applicableGhsr mRNA coexpression
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Measurements

    Ghsr mRNA coexpression
    63.5%
    c-fos-mRNA-expressing neurons

    Source sentences

    Summary
    When examining the neurochemical identity of c-fos-mRNA-expressing neurons, we found coexpression with 63.5 ± 1.9% Ghsr mRNA, 79 ± 6.8% Agrp mRNA, and 11.4 ± 2.5% Ghrh mRNA,
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  8. 08AnimalAnimal study (in vivo)Mechanism

    In mice treated with GHRP‑6, c-fos-mRNA-expressing neurons showed 79 ± 6.8% coexpression with Agrp mRNA.

    In plain wordsIn mice treated with GHRP‑6, activated neurons showed Agrp gene coexpression.

    Peptide
    GHRP-6
    Outcome
    Not applicableAgrp mRNA coexpression
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Measurements

    Agrp mRNA coexpression
    79%
    c-fos-mRNA-expressing neurons

    Source sentences

    Summary
    When examining the neurochemical identity of c-fos-mRNA-expressing neurons, we found coexpression with 63.5 ± 1.9% Ghsr mRNA, 79 ± 6.8% Agrp mRNA, and 11.4 ± 2.5% Ghrh mRNA,
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  9. 09AnimalAnimal study (in vivo)Mechanism

    In mice treated with GHRP‑6, c-fos-mRNA-expressing neurons showed 11.4 ± 2.5% coexpression with Ghrh mRNA.

    In plain wordsIn mice treated with GHRP‑6, activated neurons showed Ghrh gene coexpression.

    Peptide
    GHRP-6
    Outcome
    Not applicableGhrh mRNA coexpression
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Receptor activity and mechanism · Nervous system and cognition
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Measurements

    Ghrh mRNA coexpression
    11.4%
    c-fos-mRNA-expressing neurons

    Source sentences

    Summary
    When examining the neurochemical identity of c-fos-mRNA-expressing neurons, we found coexpression with 63.5 ± 1.9% Ghsr mRNA, 79 ± 6.8% Agrp mRNA, and 11.4 ± 2.5% Ghrh mRNA,
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.
  10. 10AnimalAnimal study (in vivo)Efficacy outcome

    In mice, intranasal GHRP‑6 increased serum GH levels.

    In plain wordsIn mice, intranasal GHRP‑6 increased growth hormone levels in blood.

    Peptide
    GHRP-6
    Outcome
    IncreaseSerum growth hormone
    Study

    mousen: not reported in source

    mice receiving intranasal secretagogues
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    5 mg/kg · intranasalAs given in this study (mouse).

    Source sentences

    Summary
    Additionally, intranasal GHRP-6 elevated GH serum levels.
    1 context sentence
    Summary · context
    This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.

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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