Setmelanotide-mediated MC4R activation improves hypothalamic obesity via CaMKK2/AMPK pathways.

Peng J, Ou Y, Zhou M, Wang X, Zhang X, Long H, Wu G, Che M, Li K, Yang L, Zhang Z, Yung KKL, Qi S, Feng Z

Frontiers in pharmacology12 Jan 2026

PMID41601974PMCIDPMC12833056DOI10.3389/fphar.2025.1730786PepBankPUB-41601974

Summary

Hypothalamic obesity (HO) is a disabling disease caused by central nervous system (CNS) damage due to neurosurgery, trauma, or tumors, especially in hypothalamus. The pathological mechanism of its neural circuits is still unclear, and there is currently no corresponding drug due to the complex etiology. G protein-coupled receptors (GPCRs) regulate neural function in many CNS diseases. Among them, melanocortin 4 receptor (MC4R) regulate metabolism and appetite in the hypothalamus. Setmelanotide, an MC4R agonist, has demonstrated anti-obesity effects in genetic forms of obesity; however, its efficacy and mechanisms in HO remain unexplored. This study explored the potential of treating HO by setmelanotide-targeted activation of MC4R in the paraventricular nucleus (PVN). We established a rat hypothalamic injury model to replicate human HO symptoms, such as hyperphagia (50% increase in food intake), elevated Lee index, and more than 25% weight gain. Immunofluorescence and immunoblot analysis showed that HO disrupted the PVN neuropeptides, leading to the inhibition of MC4R via calmodulin-dependent protein kinase kinase 2 (CaMKK2) and AMP-activated protein kinase (AMPK) signaling. Crucially, administration of setmelanotide restored CaMKK2/AMPK activity, reactivated MC4R neurons, and normalized appetite and feeding behavior during fasting-refeeding and the long-term treatment of obese rats (60% reduction in food intake), ultimately reversing obesity (23% weight loss). These findings underscore the critical role of MC4R dysfunction in hypothalamic injury and highlight the strategies to pharmacologically activate MC4R via CaMKK2/AMPK signaling to restore metabolic homeostasis, proposing a translatable therapeutic agent to manage obesity caused by CNS injury.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study5

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

01AnimalAnimal study (in vivo)Mechanism
In rats with hypothalamic obesity, setmelanotide restored CaMKK2/AMPK activity.
In plain wordsIn rats with hypothalamic obesity, setmelanotide restored CaMKK2/AMPK pathway activity.
Peptide
Setmelanotide
Outcome
IncreaseCaMKK2/AMPK activity
Study
ratn: not reported in source
Hypothalamic injury-induced obesity
Outcome group
Receptor activity and mechanism · Metabolic and weight
Studied dose
Dose not stated
Source sentences
Summary
Crucially, administration of setmelanotide restored CaMKK2/AMPK activity, reactivated MC4R neurons,
Show in the study text Report a problemFND-4160197401
02AnimalAnimal study (in vivo)Mechanism
In rats with hypothalamic obesity, setmelanotide reactivated MC4R neurons.
In plain wordsIn rats with hypothalamic obesity, setmelanotide reactivated MC4R nerve cells.
Peptide
Setmelanotide
Outcome
IncreaseMC4R neuron activity
Study
ratn: not reported in source
Hypothalamic injury-induced obesity
Outcome group
Receptor activity and mechanism · Metabolic and weight
Studied dose
Dose not stated
Source sentences
Summary
Crucially, administration of setmelanotide restored CaMKK2/AMPK activity, reactivated MC4R neurons,
Show in the study text Report a problemFND-4160197402
03AnimalAnimal study (in vivo)Efficacy outcome
In rats with hypothalamic obesity, setmelanotide normalized appetite and feeding behavior during fasting-refeeding and long-term treatment.
In plain wordsIn rats with hypothalamic obesity, setmelanotide normalized appetite and feeding behavior.
Peptide
Setmelanotide
Outcome
Not applicableAppetite and feeding behavior
Study
ratn: not reported in source
Hypothalamic injury-induced obesity
Outcome group
Appetite and food intake · Metabolic and weight
Studied dose
Dose not stated
Source sentences
Summary
and normalized appetite and feeding behavior during fasting-refeeding and the long-term treatment of obese rats (60% reduction in food intake),
Show in the study text Report a problemFND-4160197403
04AnimalAnimal study (in vivo)Efficacy outcome
In rats with hypothalamic obesity, long-term setmelanotide treatment reduced food intake by 60%.
In plain wordsIn rats with hypothalamic obesity, long-term setmelanotide treatment reduced food intake by 60%.
Peptide
Setmelanotide
Outcome
DecreaseFood intake
Study
ratn: not reported in source
Hypothalamic injury-induced obesity
Outcome group
Appetite and food intake · Metabolic and weight
Studied dose
Dose not stated
Measurements
Food intake reduction
60%
Long-term setmelanotide treatment in obese rats
Source sentences
Summary
and normalized appetite and feeding behavior during fasting-refeeding and the long-term treatment of obese rats (60% reduction in food intake),
Show in the study text Report a problemFND-4160197404
05AnimalAnimal study (in vivo)Efficacy outcome
In rats with hypothalamic obesity, setmelanotide treatment produced 23% weight loss.
In plain wordsIn rats with hypothalamic obesity, setmelanotide treatment produced 23% weight loss.
Peptide
Setmelanotide
Outcome
DecreaseBody weight
Study
ratn: not reported in source
Hypothalamic injury-induced obesity
Outcome group
Body weight · Metabolic and weight
Studied dose
Dose not stated
Measurements
Weight loss
23%
Setmelanotide treatment in obese rats
Source sentences
Summary
ultimately reversing obesity (23% weight loss).
Show in the study text Report a problemFND-4160197405

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
28 Oct 2026, 02:03 UTC
Study results updated
Version 1
27 Oct 2026, 16:36 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

Publication types

Keywords

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