Effects of GnRH immunization on the reproductive axis and thymulin.

Su S, Sun X, Zhou X, Fang F, Li Y

The Journal of endocrinology27 May 2015Cited by 9 (Europe PMC)

PMID26016747DOI10.1530/joe-14-0720PepBankPUB-26016747

Publisher page PubMedAsk about this study

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.

Natural levels measured6

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

01AnimalEndogenous levelAnimal study (in vivo)Mechanism
In GnRH-immunized rats, endogenous thymulin decreased during the first two weeks of booster immunization.
In plain wordsIn rats, natural thymulin levels decreased early after GnRH immunization.
Peptide
Thymulin (serum thymic factor)
Outcome
DecreaseEarly thymulin suppression
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
The results showed that, in the first 2 weeks of booster immunization, thymulin was repressed when reproductive hormones were severely reduced.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674701
02AnimalEndogenous levelAnimal study (in vivo)Mechanism
In immunized rats, endogenous thymulin feedback increased during later immune stages.
In plain wordsIn rats, natural thymulin feedback increased during later immune stages.
Peptide
Thymulin (serum thymic factor)
Outcome
IncreaseLater thymulin feedback
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
The self-feedback regulation of thymulin was then stimulated in later immune stages: the rising circulating thymulin upregulated LH and FSH, including GnRH in the hypothalamus, although the levels of those hormones were still significantly lower than in the control groups.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674702
03AnimalEndogenous levelAnimal study (in vivo)Mechanism
In immunized rats, rising endogenous thymulin was linked to increased LH, which remained below control levels.
In plain wordsIn rats, rising natural thymulin was linked to higher LH, but LH remained below control levels.
Peptide
Thymulin (serum thymic factor)
Outcome
IncreaseLH regulation
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
The self-feedback regulation of thymulin was then stimulated in later immune stages: the rising circulating thymulin upregulated LH and FSH, including GnRH in the hypothalamus, although the levels of those hormones were still significantly lower than in the control groups.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674703
04AnimalEndogenous levelAnimal study (in vivo)Mechanism
In immunized rats, rising endogenous thymulin was linked to increased FSH, which remained below control levels.
In plain wordsIn rats, rising natural thymulin was linked to higher FSH, but FSH remained below control levels.
Peptide
Thymulin (serum thymic factor)
Outcome
IncreaseFSH regulation
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
The self-feedback regulation of thymulin was then stimulated in later immune stages: the rising circulating thymulin upregulated LH and FSH, including GnRH in the hypothalamus, although the levels of those hormones were still significantly lower than in the control groups.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674704
05AnimalEndogenous levelAnimal study (in vivo)Mechanism
In immunized rats, rising endogenous thymulin was linked to increased hypothalamic GnRH, which remained below control levels.
In plain wordsIn rats, rising natural thymulin was linked to higher hypothalamic GnRH, which remained below control levels.
Peptide
Thymulin (serum thymic factor)
Outcome
IncreaseHypothalamic GnRH regulation
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
The self-feedback regulation of thymulin was then stimulated in later immune stages: the rising circulating thymulin upregulated LH and FSH, including GnRH in the hypothalamus, although the levels of those hormones were still significantly lower than in the control groups.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674705
06AnimalEndogenous levelAnimal study (in vivo)Mechanism
In rats, endogenous thymulin produced feedback regulation of GnRH neurons through astrocytes.
In plain wordsIn rats, natural thymulin affected GnRH neurons through astrocyte feedback.
Peptide
Thymulin (serum thymic factor)
Outcome
Not applicableAstrocyte-mediated neuronal feedback
Study
ratn: not reported in source
GnRH-immunized rats
Outcome group
Sex hormones and fertility · Endocrine and hormones
Source sentences
Summary
In astrocytes, thymulin produced a feedback effect in regulated GnRH neurons.
1 context sentence(design, population, supporting numbers)
Summary · context
We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo.
This result measures the body's own Thymulin (serum thymic factor). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-2601674706

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
21 Oct 2026, 15:58 UTC
Study results updated
Version 2
21 Oct 2026, 13:55 UTC
Study data updated · source update from Europe PMC
Version 1
21 Oct 2026, 12:50 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

PepBank is a research reference. Talk to a doctor before you use any peptide.