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Study · Animal study (in vivo) · sheep (ewe) · 2009

6 results

Melanocortins may stimulate reproduction by activating orexin neurons in the dorsomedial hypothalamus and kisspeptin neurons in the preoptic area of the ewe.

Backholer K, Smith J, Clarke IJ

Endocrinology9 Oct 2009Cited by 81 (Europe PMC)

PMID19819961 (opens in a new tab)DOI10.1210/en.2009-0604 (opens in a new tab)PepBankPUB-19819961
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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 study6

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

  1. 01AnimalAnimal study (in vivo)Efficacy outcome

    In luteal phase ewes, lateral ventricular infusion of MTII increased LH secretion.

    In plain wordsIn ewes, MTII infused into the brain increased LH secretion during the luteal phase.

    Peptide
    Melanotan II
    Outcome
    IncreaseLH secretion in luteal phase
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    10 microg/h · lateral ventricular infusionAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    Lateral ventricular infusion of MTII (10 microg/h) during the luteal phase increased LH secretion.
    1 context sentence
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.
  2. 02AnimalAnimal study (in vivo)Mechanism

    In luteal phase ewes, MTII infusion up-regulated orexin gene expression in the dorsomedial hypothalamus.

    In plain wordsIn ewes, MTII raised orexin gene activity in one brain region.

    Peptide
    Melanotan II
    Outcome
    IncreaseOrexin expression in dorsomedial hypothalamus
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    Dose not stated · lateral ventricular infusion · 20 hAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    Expression of orexin in the dorsomedial hypothalamus and kisspeptin in the POA was up-regulated by MTII treatment
    2 context sentences
    Summary · context
    MTII infusion (20 h) was repeated in luteal phase ewes and brains were harvested to measure gene expression of preproorexin and kisspeptin.
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.
  3. 03AnimalAnimal study (in vivo)Mechanism

    In luteal phase ewes, MTII infusion up-regulated kisspeptin gene expression in the preoptic area.

    In plain wordsIn ewes, MTII raised kisspeptin gene activity in one brain region.

    Peptide
    Melanotan II
    Outcome
    IncreaseKisspeptin expression in preoptic area
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    Dose not stated · lateral ventricular infusion · 20 hAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    Expression of orexin in the dorsomedial hypothalamus and kisspeptin in the POA was up-regulated by MTII treatment
    2 context sentences
    Summary · context
    MTII infusion (20 h) was repeated in luteal phase ewes and brains were harvested to measure gene expression of preproorexin and kisspeptin.
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.
  4. 04AnimalAnimal study (in vivo)Mechanism

    In luteal phase ewes, MTII infusion down-regulated Kiss1 gene expression in the arcuate nucleus.

    In plain wordsIn ewes, MTII lowered Kiss1 gene activity in one brain region.

    Peptide
    Melanotan II
    Outcome
    DecreaseKiss1 expression in arcuate nucleus
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    Dose not stated · lateral ventricular infusion · 20 hAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    Kiss1 in the arcuate nucleus was down-regulated.
    2 context sentences
    Summary · context
    MTII infusion (20 h) was repeated in luteal phase ewes and brains were harvested to measure gene expression of preproorexin and kisspeptin.
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.
  5. 05AnimalAnimal study (in vivo)Efficacy outcome

    In progesterone-primed seasonally anestrous ewes, MTII infusion raised basal LH levels.

    In plain wordsIn ewes outside the breeding season, MTII infused into the brain raised basal LH levels.

    Peptide
    Melanotan II
    Outcome
    IncreaseBasal LH in seasonal anestrus
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    10 microg/h · lateral ventricular infusion · 30 hAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    A rise in basal LH levels was seen
    2 context sentences
    Summary · context
    Seasonally anestrous ewes were progesterone primed and then treated (lateral ventricular) with MTII (10 microg/h) or vehicle for 30 h, and blood samples were collected every 2 h from 4 h before infusion until 6 h afterward to monitor acute response in terms of LH levels.
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.
  6. 06AnimalAnimal study (in vivo)Efficacy outcome

    In seasonally anestrous ewes, LH samples around the predicted surge did not indicate that an ovulatory event occurred after MTII.

    In plain wordsIn ewes outside the breeding season, MTII did not trigger signs of ovulation.

    Peptide
    Melanotan II
    Outcome
    No significant changeOvulatory event in seasonal anestrus
    Study

    sheep (ewe)n: not reported in source

    in vivo, ewes
    Outcome group
    Sex hormones and fertility · Reproductive and sexual health
    Studied dose
    10 microg/h · lateral ventricular infusion · 30 hAs given in this study (sheep (ewe)).

    Source sentences

    Summary
    samples collected around the time of the predicted LH surge did not indicate that an ovulatory event occurred.
    2 context sentences
    Summary · context
    Seasonally anestrous ewes were progesterone primed and then treated (lateral ventricular) with MTII (10 microg/h) or vehicle for 30 h, and blood samples were collected every 2 h from 4 h before infusion until 6 h afterward to monitor acute response in terms of LH levels.
    Summary · context
    To further test the hypothesis that melanocortins stimulate the reproductive axis, we treated ewes with melanocortin agonist (MTII) in the luteal phase of the estrous cycle and during seasonal anestrus.

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

    10 Oct 2026, 09:43 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 03:04 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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