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Study · Measured the body's own peptide · 1995

2 results

No changes in the number of vasoactive intestinal polypeptide (VIP)-expressing neurons in the suprachiasmatic nucleus of homosexual men; comparison with vasopressin-expressing neurons.

Zhou JN, Hofman MA, Swaab DF

Brain research1 Feb 1995Cited by 9 (Europe PMC)

PMID7749749 (opens in a new tab)DOI10.1016/0006-8993(94)01430-p (opens in a new tab)PepBankPUB-07749749
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 study2

No result from this study comes from a test of the peptide.

Natural levels measured2

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.

  1. 01HumanEndogenous levelObservational studyOther

    In homosexual men, the number of neurons expressing the body's own VIP in the suprachiasmatic nucleus did not differ from that in heterosexual men.

    In plain wordsIn homosexual men, the number of neurons with the body's own VIP in a brain clock region was no different from heterosexual men.

    Peptide
    Vasoactive intestinal peptide (VIP, aviptadil)
    Outcome
    No significant changeNumber of VIP-expressing neurons in the suprachiasmatic nucleus
    Study

    n: not reported in source

    Comparator
    Heterosexual men
    Outcome group
    Endogenous peptide levels · Nervous system and cognition

    Source sentences

    Summary
    The present measurements in the same individuals showed that there is no difference in the number of vasoactive intestinal polypeptide (VIP)-expressing neurons in the SCN.
    1 context sentence
    Summary · context
    In an earlier study we found more than twice as many vasopressin (AVP) neurons in the suprachiasmatic nucleus (SCN) of homosexual men as compared to heterosexual men.

    This result measures the body's own Vasoactive intestinal peptide (VIP, aviptadil). Nobody was given the peptide. It is not evidence about taking it.

  2. 02HumanEndogenous levelObservational studyOther

    In homosexual men, the nuclear diameter of neurons expressing the body's own VIP in the suprachiasmatic nucleus was reduced compared with heterosexual men.

    In plain wordsIn homosexual men, brain clock neurons that make the body's own VIP had smaller nuclei than in heterosexual men.

    Peptide
    Vasoactive intestinal peptide (VIP, aviptadil)
    Outcome
    DecreaseNuclear diameter of VIP neurons in the suprachiasmatic nucleus
    Study

    n: not reported in source

    Comparator
    Heterosexual men
    Outcome group
    Endogenous peptide levels · Nervous system and cognition

    Source sentences

    Summary
    The reduced nuclear diameter of both VIP and AVP neurons in the SCN as found in homosexual men
    1 context sentence
    Summary · context
    In an earlier study we found more than twice as many vasopressin (AVP) neurons in the suprachiasmatic nucleus (SCN) of homosexual men as compared to heterosexual men.

    This result measures the body's own Vasoactive intestinal peptide (VIP, aviptadil). Nobody was given the peptide. It is not evidence about taking it.

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

    12 Oct 2026, 12:58 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 12:41 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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