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Study · Animal study (in vivo) · rat · 1991

9 results

Sex differences in growth hormone (GH) secretion by rats administered GH-releasing hexapeptide.

Bercu BB, Weideman CA, Walker RF

Endocrinology1 Nov 1991Cited by 15 (Europe PMC)

PMID1935789 (opens in a new tab)DOI10.1210/endo-129-5-2592 (opens in a new tab)PepBankPUB-01935789
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 study9

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

  1. 01AnimalAnimal study (in vivo)Efficacy outcome

    In rats given GHRP‑6, GH was significantly elevated at 15 min in six of six females versus three of six males.

    In plain wordsIn rats given GHRP‑6, GH rose at 15 min in six of six females versus three of six males.

    Peptide
    GHRP-6
    Outcome
    IncreaseAcute GH response by sex
    Study

    ratn = 12

    male and female rats
    Comparator
    Male rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    0.5 mg/kg · subcutaneousAs given in this study (rat).

    Source sentences

    Summary
    Plasma GH was significantly elevated in female rats (six of six) compared to male rats (three of six) 15 min after administration of a single sc injection of GHRP-6 (0.5 mg/kg).
  2. 02AnimalAnimal study (in vivo)Efficacy outcome

    In conscious male rats, GHRP‑6 administration was associated with suppression of episodic GH secretion.

    In plain wordsIn male rats, GHRP‑6 was linked to reduced episodic GH secretion.

    Peptide
    GHRP-6
    Outcome
    DecreaseEpisodic GH secretion in males
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated

    Source sentences

    Summary
    In male rats, GHRP-6 administration was associated with suppression of episodic GH secretion and desensitization to a second injection administered 6 h later
    1 context sentence
    Summary · context
    The purpose of this study was to compare GH secretion after the administration of GH-releasing hexapeptide (GHRP-6) in conscious male and female rats.
  3. 03AnimalAnimal study (in vivo)Efficacy outcome

    In conscious male rats, GHRP‑6 administration was associated with desensitization to a second injection 6 h later.

    In plain wordsIn male rats, the GH response decreased with a second GHRP‑6 injection.

    Peptide
    GHRP-6
    Outcome
    DecreaseRepeat-dose response in males
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated · 6 hAs given in this study (rat).

    Source sentences

    Summary
    In male rats, GHRP-6 administration was associated with suppression of episodic GH secretion and desensitization to a second injection administered 6 h later
    1 context sentence
    Summary · context
    The purpose of this study was to compare GH secretion after the administration of GH-releasing hexapeptide (GHRP-6) in conscious male and female rats.
  4. 04AnimalAnimal study (in vivo)Efficacy outcome

    In conscious female rats, GH secretion occurred after both GHRP‑6 injections.

    In plain wordsIn female rats, both GHRP‑6 injections stimulated GH secretion.

    Peptide
    GHRP-6
    Outcome
    IncreaseRepeat-dose response in females
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated

    Source sentences

    Summary
    whereas in female rats, GH secretion occurred after both GHRP-6 injections.
    1 context sentence
    Summary · context
    The purpose of this study was to compare GH secretion after the administration of GH-releasing hexapeptide (GHRP-6) in conscious male and female rats.
  5. 05AnimalAnimal study (in vivo)Efficacy outcome

    In male rats, twice-daily GHRP‑6 decreased mean plasma GH from 110 to 2.8 ng/ml after 14 days.

    In plain wordsIn male rats, repeated GHRP‑6 decreased mean blood GH from baseline.

    Peptide
    GHRP-6
    Outcome
    DecreaseChronic plasma GH in males
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated · 14 daysAs given in this study (rat).

    Measurements

    Mean GH
    110 ng/ml
    male baseline
    Mean GH
    2.8 ng/ml
    male after treatment

    Source sentences

    Summary
    After 14 consecutive days of administering GHRP-6 twice per day, mean plasma GH concentrations in males decreased from 110 +/- 91 to 2.8 +/- 0.6 ng/ml (P less than 0.05) and in females increased from 170 +/- 53 ng/ml to 361 +/- 81 ng/ml (P less than 0.05).
  6. 06AnimalAnimal study (in vivo)Efficacy outcome

    In female rats, twice-daily GHRP‑6 increased mean plasma GH from 170 to 361 ng/ml after 14 days.

    In plain wordsIn female rats, repeated GHRP‑6 increased mean blood GH from baseline.

    Peptide
    GHRP-6
    Outcome
    IncreaseChronic plasma GH in females
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated · 14 daysAs given in this study (rat).

    Measurements

    Mean GH
    170 ng/ml
    female baseline
    Mean GH
    361 ng/ml
    female after treatment

    Source sentences

    Summary
    After 14 consecutive days of administering GHRP-6 twice per day, mean plasma GH concentrations in males decreased from 110 +/- 91 to 2.8 +/- 0.6 ng/ml (P less than 0.05) and in females increased from 170 +/- 53 ng/ml to 361 +/- 81 ng/ml (P less than 0.05).
  7. 07AnimalAnimal study (in vivo)Efficacy outcome

    After GHRP‑6 treatment, female rats had lower pituitary GH concentrations than male rats.

    In plain wordsIn rats given GHRP‑6, females had lower pituitary GH levels than males.

    Peptide
    GHRP-6
    Outcome
    DecreasePituitary GH by sex
    Study

    ratn: not reported in source

    male and female rats
    Comparator
    Male rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated · 14 daysAs given in this study (rat).

    Measurements

    Pituitary GH
    5.1 micrograms/mg
    female
    Pituitary GH
    12.9 micrograms/mg
    male

    Source sentences

    Summary
    After 14 consecutive days of GHRP-6 administration, the mean pituitary GH concentration in female rats was significantly lower than that in male rats (5.1 +/- 0.2 vs. 12.9 +/- 1.2 micrograms/mg, respectively).
  8. 08AnimalAnimal study (in vivo)Mechanism

    In female rats after GHRP‑6, lower pituitary GH concentrations correlated with higher GH secretion.

    In plain wordsIn female rats given GHRP‑6, lower pituitary GH was linked to higher GH secretion.

    Peptide
    GHRP-6
    Outcome
    DecreasePituitary GH association with secretion
    Study

    ratn: not reported in source

    male and female rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones
    Studied dose
    Dose not stated

    Source sentences

    Summary
    Lower pituitary GH concentrations in females correlated with higher GH secretion after GHRP-6 administration.

Studies that did not test the peptide alone1

In this study, GHRP-6 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-6.

  1. 09AnimalNot a test of GHRP-6 aloneAnimal study (in vivo)Mechanism

    In pentobarbital-anesthetized male rats, the GHRP‑6 desensitization observed in conscious males was absent.

    In plain wordsIn male rats under pentobarbital anesthesia, GHRP‑6 did not show the desensitization seen in conscious males.

    Peptide
    GHRP-6
    Outcome
    DecreaseAnesthesia and desensitization
    Study

    ratn: not reported in source

    male and female rats
    Comparator
    Conscious male rats
    Outcome group
    Growth hormone and IGF-1 · Endocrine and hormones

    Source sentences

    Summary
    Desensitization to GHRP-6 in conscious male rats was not observed in pentobarbital-anesthetized male rats, suggesting that GHRP-6 administration enhanced somatostatin release in the conscious state.

    In this study, GHRP-6 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-6.

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

    21 Oct 2026, 15:59 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 03:13 UTC

    First added · source update from Europe PMC

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