Growth Hormone (GH) but not IGF-I-Secretion is Stimulated in Aged Rats by Chronic Hexarelin and GHRP-6 administration.

Settembrini B, Figueroa J, Gallardo M, Chiocchio S

Endocrine regulations1 Mar 1998Cited by 2 (Europe PMC)

PMID10407366PepBankPUB-10407366

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 study15

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

01AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats, 20 µg/kg of hexarelin was the minimal dose producing the maximal GH response.
In plain wordsIn young and old rats, 20 µg/kg of hexarelin was the smallest dose giving the largest growth hormone response.
Peptide
Hexarelin
Outcome
IncreaseMinimal dose giving maximal GH response
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Measurements
Minimal dose with maximal GH response
20 µg/kg bw
HEXA
Source sentences
Summary
It was found that 20 µg/kg bw of HEXA or GHRP-6 was the minimal dose producing the maximal GH response.
2 context sentences(design, population, supporting numbers)
Summary · context
To determine the minimal effective dose of HEXA and GHRP-6 in aged animals, different doses (5, 10, 20, 40, and 80 µg/kg) of either HEXA or GHRP-6 were administered subcutaneously to young and aged rats.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736602
02AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats, 20 µg/kg of GHRP‑6 was the minimal dose producing the maximal GH response.
In plain wordsIn young and old rats, 20 µg/kg of GHRP‑6 was the smallest dose giving the largest growth hormone response.
Peptide
GHRP-6
Outcome
IncreaseMinimal dose giving maximal GH response
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Measurements
Minimal dose with maximal GH response
20 µg/kg bw
GHRP-6
Source sentences
Summary
It was found that 20 µg/kg bw of HEXA or GHRP-6 was the minimal dose producing the maximal GH response.
2 context sentences(design, population, supporting numbers)
Summary · context
To determine the minimal effective dose of HEXA and GHRP-6 in aged animals, different doses (5, 10, 20, 40, and 80 µg/kg) of either HEXA or GHRP-6 were administered subcutaneously to young and aged rats.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736603
03AnimalAnimal study (in vivo)Efficacy outcome
In rats given the minimal dose, PRL and LH measurements showed that hexarelin stimulated GH release specifically.
In plain wordsIn rats, hexarelin raised growth hormone specifically, as shown by measuring two other hormones, PRL and LH.
Peptide
Hexarelin
Outcome
IncreaseSelectivity of GH release versus PRL and LH
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Source sentences
Summary
Plasma PRL and LH determinations in the animals injected with the minimal dose showed that HEXA and GHRP-6 stimulate the GH release specifically.
1 context sentence(design, population, supporting numbers)
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736604
04AnimalAnimal study (in vivo)Efficacy outcome
In rats given the minimal dose, PRL and LH measurements showed that GHRP‑6 stimulated GH release specifically.
In plain wordsIn rats, GHRP‑6 raised growth hormone specifically, as shown by measuring two other hormones, PRL and LH.
Peptide
GHRP-6
Outcome
IncreaseSelectivity of GH release versus PRL and LH
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Source sentences
Summary
Plasma PRL and LH determinations in the animals injected with the minimal dose showed that HEXA and GHRP-6 stimulate the GH release specifically.
1 context sentence(design, population, supporting numbers)
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736605
05AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats treated with hexarelin for 15 days, GH was still released in response to the repeated administration.
In plain wordsIn young and old rats, hexarelin still released growth hormone after 15 days of twice-daily treatment.
Peptide
Hexarelin
Outcome
IncreaseGH response after 15 days of treatment
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 daysAs given in this study (rat).
Source sentences
Summary
It was found that both young and aged animals released GH in response to the repeated administration of GH releasing peptides after 15 days of treatment.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736606
06AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats treated with GHRP‑6 for 15 days, GH was still released in response to the repeated administration.
In plain wordsIn young and old rats, GHRP‑6 still released growth hormone after 15 days of twice-daily treatment.
Peptide
GHRP-6
Outcome
IncreaseGH response after 15 days of treatment
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 daysAs given in this study (rat).
Source sentences
Summary
It was found that both young and aged animals released GH in response to the repeated administration of GH releasing peptides after 15 days of treatment.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736607
07AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats treated with hexarelin for 30 days, plasma GH did not change on acute testing with hexarelin.
In plain wordsIn young and old rats, after 30 days of hexarelin treatment, a new hexarelin dose no longer changed growth hormone.
Peptide
Hexarelin
Outcome
No significant changeGH response after 30 days of treatment
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 30 daysAs given in this study (rat).
Source sentences
Summary
However, after 30 days of treatment plasma GH did not change when young and aged HEXA treated animals were acutely tested with such peptide, but increased significantly in the GHRP-6 treated animals when they were acutely tested with GHRP-6.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736608
08AnimalAnimal study (in vivo)Efficacy outcome
In young and aged rats treated with GHRP‑6 for 30 days, plasma GH increased significantly on acute testing with GHRP‑6.
In plain wordsIn young and old rats, after 30 days of GHRP‑6 treatment, a new GHRP‑6 dose still raised growth hormone.
Peptide
GHRP-6
Outcome
IncreaseGH response after 30 days of treatment
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 30 daysAs given in this study (rat).
Source sentences
Summary
However, after 30 days of treatment plasma GH did not change when young and aged HEXA treated animals were acutely tested with such peptide, but increased significantly in the GHRP-6 treated animals when they were acutely tested with GHRP-6.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736609
09AnimalAnimal study (in vivo)Efficacy outcome
In young rats chronically treated with hexarelin, plasma IGF-I increased when they were acutely tested with hexarelin.
In plain wordsIn young rats treated with hexarelin for weeks, IGF-I rose when they received a new hexarelin dose.
Peptide
Hexarelin
Outcome
IncreasePlasma IGF-I in young rats after chronic treatment
Study
ratn: not reported in source
Young rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 or 30 daysAs given in this study (rat).
Source sentences
Summary
In response to the long term treatment with the GH-releasing peptides, plasma IGF-I levels increased in young animals when they were acutely tested with the corresponding peptide.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736610
10AnimalAnimal study (in vivo)Efficacy outcome
In young rats chronically treated with GHRP‑6, plasma IGF-I increased when they were acutely tested with GHRP‑6.
In plain wordsIn young rats treated with GHRP‑6 for weeks, IGF-I rose when they received a new GHRP‑6 dose.
Peptide
GHRP-6
Outcome
IncreasePlasma IGF-I in young rats after chronic treatment
Study
ratn: not reported in source
Young rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 or 30 daysAs given in this study (rat).
Source sentences
Summary
In response to the long term treatment with the GH-releasing peptides, plasma IGF-I levels increased in young animals when they were acutely tested with the corresponding peptide.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736611
11AnimalAnimal study (in vivo)Efficacy outcome
In aged rats, plasma IGF-I was not modified by acute hexarelin after 15 or 30 days of treatment.
In plain wordsIn old rats treated with hexarelin for weeks, IGF-I did not change after a new hexarelin dose.
Peptide
Hexarelin
Outcome
No significant changePlasma IGF-I in aged rats after chronic treatment
Study
ratn: not reported in source
Aged rats (22-24 months)
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 or 30 daysAs given in this study (rat).
Source sentences
Summary
However, plasma IGF-I levels in aged rats were not modified by the acute administration of either HEXA or GHRP-6 after 15 or 30 days of treatment.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736612
12AnimalAnimal study (in vivo)Efficacy outcome
In aged rats, plasma IGF-I was not modified by acute GHRP‑6 after 15 or 30 days of treatment.
In plain wordsIn old rats treated with GHRP‑6 for weeks, IGF-I did not change after a new GHRP‑6 dose.
Peptide
GHRP-6
Outcome
No significant changePlasma IGF-I in aged rats after chronic treatment
Study
ratn: not reported in source
Aged rats (22-24 months)
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg twice a day · subcutaneous · 15 or 30 daysAs given in this study (rat).
Source sentences
Summary
However, plasma IGF-I levels in aged rats were not modified by the acute administration of either HEXA or GHRP-6 after 15 or 30 days of treatment.
2 context sentences(design, population, supporting numbers)
Summary · context
Based on the results obtained in the latter experiments, young and aged rats were chronically treated with s.c. injections of 20 µg/kg twice a day for 15 or 30 days.
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736613
13AnimalAnimal study (in vivo)Efficacy outcome
Hexarelin stimulated GH release in aged rats, and the size of the response was similar to that in young rats.
In plain wordsIn old rats, hexarelin raised growth hormone about as much as it did in young rats.
Peptide
Hexarelin
Outcome
IncreaseGH release in aged versus young rats
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Comparator
Young rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Source sentences
Summary
HEXA and GHRP-6 stimulated GH release in aged rats and the magnitude of GH responses was similar to that in young rats
1 context sentence(design, population, supporting numbers)
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736614
14AnimalAnimal study (in vivo)Efficacy outcome
GHRP‑6 stimulated GH release in aged rats, and the size of the response was similar to that in young rats.
In plain wordsIn old rats, GHRP‑6 raised growth hormone about as much as it did in young rats.
Peptide
GHRP-6
Outcome
IncreaseGH release in aged versus young rats
Study
ratn: not reported in source
Young and aged (22-24 months) rats
Comparator
Young rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Studied dose
20 µg/kg · subcutaneousAs given in this study (rat).
Source sentences
Summary
HEXA and GHRP-6 stimulated GH release in aged rats and the magnitude of GH responses was similar to that in young rats
1 context sentence(design, population, supporting numbers)
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
Report a problemFND-1040736615

Studies that did not test the peptide alone1

In this study, Hexarelin 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 Hexarelin.

15AnimalNot a test of Hexarelin aloneAnimal study (in vivo)Other
In young rats, the GH response to hexarelin was increased by ketamine-xylazine anesthesia and decreased by tribromoethanol, compared with conscious rats.
In plain wordsIn young rats, one anesthetic raised and another lowered the growth hormone response to hexarelin compared with conscious rats.
Peptide
Hexarelin
Outcome
MixedGH response to hexarelin under anesthesia
Study
ratn: not reported in source
Young rats
Outcome group
Growth hormone and IGF-1 · Endocrine and hormones
Source sentences
Summary
When compared to the changes found in conscious rats, the GH-response to HEXA was increased by ketamine-xylazine anesthesia, while it was decreased by tribromoethanol.
1 context sentence(design, population, supporting numbers)
Summary · context
The present studies were designed to investigate in aged rats (22-24 months old) the effectiveness and specificity of acute hexarelin (HEXA) administration on the release of growth hormone (GH), the minimal dose of the peptide that produces the maximal GH secretion and the effects of long term treat…
In this study, Hexarelin 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 Hexarelin.
Report a problemFND-1040736601

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.

Version 3Current
13 Oct 2026, 21:44 UTC
Study results updated
Version 2
13 Oct 2026, 16:31 UTC
Study data updated · source update from Europe PMC
Version 1
9 Oct 2026, 03:13 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

Publication types

Journal Article

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