Downregulation of melanocortin receptors in brain areas involved in food intake and reward mechanisms in obese (OLETF) rats.

Lindblom J, Schiöth HB, Watanobe H, Suda T, Wikberg JE, Bergström L

Brain research1 Jan 2000Cited by 17 (Europe PMC)

PMID10661510DOI10.1016/s0006-8993(99)02125-3PepBankPUB-10661510

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 study5

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

Studies that did not test the peptide alone5

In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

01AnimalNot a test of Melanotan I (afamelanotide) aloneAnimal study (in vivo)Mechanism
In OLETF rats, total [125I]NDP-MSH melanocortin receptor binding was reduced in the ventromedial hypothalamic nucleus compared with LETO controls.
In plain wordsIn obese rats, there were fewer melanocortin receptors in one brain area that controls feeding than in control rats.
Peptide
Melanotan I (afamelanotide)
Outcome
DecreaseTotal MC receptor binding in ventromedial hypothalamic nucleus
Study
ratn: not reported in source
ovariectomized estradiol-replaced female OLETF rats
Comparator
LETO rats
Outcome group
Receptor activity and mechanism · Nervous system and cognition
Source sentences
Summary
We found that OLETF rats show a reduction in total [125I]NDP-MSH MC receptor binding in the ventromedial hypothalamic nucleus
1 context sentence(design, population, supporting numbers)
Summary · context
We investigated by autoradiography if the expression of MC receptors were altered in ovariectomized estradiol-replaced female OLETF rats compared to their controls (Long-Evans-Tokushima-Otsuka (LETO) rats).
In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).
Report a problemFND-1066151001
02AnimalNot a test of Melanotan I (afamelanotide) aloneAnimal study (in vivo)Mechanism
In OLETF rats, melanocortin receptor levels in the arcuate nucleus were not changed compared with LETO controls.
In plain wordsIn obese rats, melanocortin receptor levels in one brain area did not differ from control rats.
Peptide
Melanotan I (afamelanotide)
Outcome
No significant changeMC receptor level in arcuate nucleus
Study
ratn: not reported in source
ovariectomized estradiol-replaced female OLETF rats
Comparator
LETO rats
Outcome group
Receptor activity and mechanism · Nervous system and cognition
Source sentences
Summary
The levels of MC receptors in the arcuate nucleus and the paraventricular hypothalamic nucleus were not changed.
1 context sentence(design, population, supporting numbers)
Summary · context
We investigated by autoradiography if the expression of MC receptors were altered in ovariectomized estradiol-replaced female OLETF rats compared to their controls (Long-Evans-Tokushima-Otsuka (LETO) rats).
In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).
Report a problemFND-1066151002
03AnimalNot a test of Melanotan I (afamelanotide) aloneAnimal study (in vivo)Mechanism
In OLETF rats, melanocortin receptor levels in the paraventricular hypothalamic nucleus were not changed compared with LETO controls.
In plain wordsIn obese rats, melanocortin receptor levels in one brain area did not differ from control rats.
Peptide
Melanotan I (afamelanotide)
Outcome
No significant changeMC receptor level in paraventricular hypothalamic nucleus
Study
ratn: not reported in source
ovariectomized estradiol-replaced female OLETF rats
Comparator
LETO rats
Outcome group
Receptor activity and mechanism · Nervous system and cognition
Source sentences
Summary
The levels of MC receptors in the arcuate nucleus and the paraventricular hypothalamic nucleus were not changed.
1 context sentence(design, population, supporting numbers)
Summary · context
We investigated by autoradiography if the expression of MC receptors were altered in ovariectomized estradiol-replaced female OLETF rats compared to their controls (Long-Evans-Tokushima-Otsuka (LETO) rats).
In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).
Report a problemFND-1066151003
04AnimalNot a test of Melanotan I (afamelanotide) aloneAnimal study (in vivo)Mechanism
In OLETF rats, melanocortin receptor binding was reduced in the nucleus accumbens shell compared with LETO controls.
In plain wordsIn obese rats, there were fewer melanocortin receptors in a brain reward area than in control rats.
Peptide
Melanotan I (afamelanotide)
Outcome
DecreaseMC receptor binding in nucleus accumbens shell
Study
ratn: not reported in source
ovariectomized estradiol-replaced female OLETF rats
Comparator
LETO rats
Outcome group
Receptor activity and mechanism · Nervous system and cognition
Source sentences
Summary
Interestingly, the OLETF rats also showed reduced MC-receptor binding in areas such as the nucleus accumbens shell, and the ventral tegmental area, both of which are believed to be involved in reward systems.
1 context sentence(design, population, supporting numbers)
Summary · context
We investigated by autoradiography if the expression of MC receptors were altered in ovariectomized estradiol-replaced female OLETF rats compared to their controls (Long-Evans-Tokushima-Otsuka (LETO) rats).
In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).
Report a problemFND-1066151004
05AnimalNot a test of Melanotan I (afamelanotide) aloneAnimal study (in vivo)Mechanism
In OLETF rats, melanocortin receptor binding was reduced in the ventral tegmental area compared with LETO controls.
In plain wordsIn obese rats, there were fewer melanocortin receptors in a brain reward area than in control rats.
Peptide
Melanotan I (afamelanotide)
Outcome
DecreaseMC receptor binding in ventral tegmental area
Study
ratn: not reported in source
ovariectomized estradiol-replaced female OLETF rats
Comparator
LETO rats
Outcome group
Receptor activity and mechanism · Nervous system and cognition
Source sentences
Summary
Interestingly, the OLETF rats also showed reduced MC-receptor binding in areas such as the nucleus accumbens shell, and the ventral tegmental area, both of which are believed to be involved in reward systems.
1 context sentence(design, population, supporting numbers)
Summary · context
We investigated by autoradiography if the expression of MC receptors were altered in ovariectomized estradiol-replaced female OLETF rats compared to their controls (Long-Evans-Tokushima-Otsuka (LETO) rats).
In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).
Report a problemFND-1066151005

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

Subjects

Terms as the source lists them.

Publication types

MeSH terms

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