PT-141 (Bremelanotide):
Melanocortin Agonist Research
PT-141 (Bremelanotide) is a synthetic cyclic heptapeptide melanocortin receptor agonist derived from Melanotan II. It acts on central melanocortin receptors and has been extensively studied in preclinical models for its distinctive CNS-mediated mechanism of action.
What Is PT-141?
PT-141 (Bremelanotide; cyclo[Nle4, Asp5, D-Phe7]-α-MSH(4-10)) is a synthetic cyclic heptapeptide derived from Melanotan II by removal of the C-terminal amide. Discovered during Melanotan II research at the University of Arizona, PT-141 was found to activate central melanocortin receptors (particularly MC3R and MC4R) with high affinity and selectivity, while lacking significant activity at MC1R (which mediates skin tanning) compared to its parent compound.
A synthetic form of Bremelanotide (Vyleesi) is FDA-approved for a specific indication in premenopausal women. The compound continues to be a valuable research tool for studying the central melanocortin system, dopaminergic signaling, hypothalamic circuits, and related CNS pathways. Lumen Peppers provides research-grade PT-141 for in vitro and preclinical laboratory investigation only.
Key Research Findings
PT-141 research spans central melanocortin system biology, dopaminergic neuroscience, hypothalamic circuit research, and metabolic regulation.
Central Melanocortin Activation
PT-141 binds MC3R and MC4R in hypothalamic and limbic brain regions with high affinity. Rodent studies confirm CNS-mediated action with intracerebroventricular (ICV) administration producing effects comparable to peripheral SC dosing, confirming the primary site of action is central.
Dopaminergic Modulation
Microdialysis studies show PT-141 increases extracellular dopamine in the nucleus accumbens and medial preoptic area (mPOA) of the hypothalamus. This dopaminergic activation is proposed as the key downstream mechanism linking MC4R activation to reward and motivational circuits.
Hypothalamic Circuit Research
PT-141 activates oxytocin neurons in the paraventricular nucleus (PVN) of the hypothalamus in rodent studies. Oxytocin release downstream of MC4R activation is proposed as an additional signaling pathway contributing to PT-141's CNS effects.
Metabolic Research
MC4R is a critical regulator of energy homeostasis. MC4R-null mice are hyperphagic and obese; MC4R agonism with PT-141 in rodent models reduces food intake and increases energy expenditure — providing a research tool for studying hypothalamic energy regulation.
Blood Pressure Research
PT-141 transiently elevates blood pressure in rodent models, attributed to peripheral vascular MC receptor activation. This cardiovascular effect has been characterized across dose ranges and has been incorporated into preclinical safety profiling protocols.
MC Receptor Selectivity
PT-141's selectivity profile (MC3R/MC4R ≫ MC1R/MC5R) has made it a valuable pharmacological tool for dissecting the specific contributions of individual melanocortin receptor subtypes in CNS and peripheral tissue research.
Proposed Mechanisms of Action
PT-141 binds MC3R and MC4R (Gs-coupled GPCRs) in hypothalamic and limbic neurons. Receptor activation increases intracellular cAMP via adenylyl cyclase, activating PKA and CREB-mediated gene transcription — triggering downstream neurotransmitter release cascades.
MC4R activation in hypothalamic neurons projecting to the nucleus accumbens (NAc) increases dopamine release in the mesolimbic reward pathway. This DA elevation in the NAc is detectable by microdialysis within 30–60 min of SC PT-141 administration in rodents.
MC4R-expressing oxytocin neurons in the paraventricular nucleus (PVN) are directly activated by PT-141, triggering oxytocin release into both the peripheral circulation and brain regions including the mPOA — mediating hypothalamic circuit effects.
The arcuate nucleus (ARC) of the hypothalamus integrates energy signals through MC3R/MC4R on second-order neurons projecting to PVN, LH, and brainstem. PT-141/MC4R agonism promotes anorexigenic signaling, reduces NPY/AgRP activity, and increases POMC-derived peptide tone.
In some peripheral research models, PT-141 activates nitric oxide synthase (NOS) via MC receptor coupling to eNOS, contributing to vascular tone changes. This peripheral NO mechanism has been studied in vascular biology models alongside the central MC4R pathway.
Active Research Applications
CNS Melanocortin Research
Hypothalamic circuit studies using ICV and SC PT-141 to map MC3R/MC4R-expressing neuron populations and their downstream projections.
Dopamine Biology
In vivo microdialysis studies measuring real-time dopamine release in NAc, mPOA, and PFC following MC agonist administration.
Energy Homeostasis
Food intake, energy expenditure, and body weight studies in wildtype and MC4R-null mouse models comparing MC agonist profiles.
Receptor Pharmacology
Radioligand binding studies, cAMP reporter assays, and β-arrestin recruitment assays characterizing PT-141 activity at MC1-5R subtypes.
Vascular Biology
Blood pressure telemetry, vascular tone, and NOS pathway studies examining PT-141's peripheral cardiovascular effects across dose ranges.
Drug Development Tool
Use as a reference MC4R agonist in comparative pharmacology studies alongside other melanocortin analogs, bremelanotide metabolites, and next-generation MC agonists.
Protocol Notes for Researchers
PT-141 (Bremelanotide) — Research Grade ≥99%
Research-grade purity ≥99% · Third-party HPLC verified · Ships from the U.S.
All products sold by Lumen Peppers are intended exclusively for in vitro laboratory research and investigative purposes. These compounds are not approved by the FDA for human or veterinary use. They are not drugs, supplements, or medications. Lumen Peppers makes no therapeutic claims. Researchers are solely responsible for ensuring compliance with all applicable laws and regulations in their jurisdiction.