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PT-141 (Bremelanotide) | CAS: 189691-06-3

CAS Number:
189691-06-3
Chemical Classification:
Research peptide

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PT-141 (Bremelanotide) (CAS 189691-06-3) is a cyclic melanocortin receptor agonist used to interrogate central melanocortin-4 signaling in specialty endocrine and behavioral research. Peripheral versus central receptor engagement, dose, and species differences mean that autonomic and appetitive readouts do not always align across published protocols. Researchers apply the peptide in intracerebroventricular titration studies, melanocortin-receptor binding competition assays, and rodent models monitoring feeding suppression or thermoregulatory shifts. Analytical batches include COA, LC-MS, HPLC, and NMR documentation; laboratory use only.

CAS
189691-06-3
Molecular Formula
C50H68N14O10
Molecular Weight
1025.2 g/mol
Purity
≥98%
Appearance
White lyophilized powder
Storage
Store at -20°C

Analytical Documentation

COA✓ Available
LC-MS✓ Available
HPLC✓ Available
NMR✓ Available

Research Inquiry

Overview

PT-141, known as bremelanotide in pharmaceutical research literature, is a cyclic heptapeptide melanocortin receptor agonist derived from melanotan II scaffold with modified pharmacokinetic properties studied in specialty receptor pharmacology programs. The peptide activates melanocortin MC3R and MC4R with bias profiles distinct from alpha-melanocyte stimulating hormone, enabling research on central melanocortin circuits governing autonomic and behavioral outputs. PT-141 serves as a ligand for mapping melanocortin signaling in hypothalamic neurons, spinal cord autonomic pathways, and peripheral MC receptor expressing tissues in controlled laboratory experiments without sexual medicine clinical claims. Supplied at ≥98% purity (C50H68N14O10; 1025.2 g/mol), this material supports controlled laboratory investigation under research-use-only conditions.

Mechanism of Action

PT-141 binds MC4R on hypothalamic and brainstem neurons, activating Gs and Gq coupling that modulates autonomic outflow and behavioral phenotypes in rodent research models. MC3R engagement on immune and central cells contributes to anti-inflammatory cytokine profiles in some stress experiments. Unlike peripherally restricted melanocortin agonists, PT-141 crosses the blood-brain barrier in research dosing paradigms, centralizing mechanism studies. Downstream cAMP elevation regulates pro-opiomelanocortin neuron feedback loops. PT-141 does not act at MC1R melanogenic pathways as potently as melanotan II in standard pigmentation research assays.

Receptor Binding & Signaling

PT-141 exhibits high affinity for MC3R and MC4R with lower MC1R and MC5R activity relative to melanotan II in cell-based assays. Selectivity panels exclude meaningful GLP-1R or dopamine receptor activation at research concentrations. Beta-arrestin bias differs from alpha-MSH, supporting biased agonism research. Species ortholog differences affect potency in rodent versus human receptor cell lines.

Research Applications

Melanocortin MC4R central signaling

Neurons from paraventricular nucleus and solitary tract nucleus express MC4R studied with PT-141 stimulation in electrophysiology and c-Fos mapping research. MC4R knockout animals attribute phenotypes to receptor-specific pathways. Platforms advance central melanocortin neurobiology.

Autonomic and cardiovascular reflex research

Rodent models measure blood pressure, heart rate variability, and baroreceptor reflex parameters after PT-141 administration in controlled IACUC-approved protocols. Spinal cord MC receptor expression studied in autonomic outflow research. Focus remains autonomic physiology not clinical endpoints.

Biased agonism pharmacology

Cell lines co-expressing MC4R with biosensors measure cAMP versus beta-arrestin recruitment after PT-141 compared with alpha-MSH and melanotan II. Structure-activity studies on cyclic peptide scaffold use PT-141 as reference ligand. Medicinal chemistry research on melanocortin peptides benefits from defined bias profiles.

Metabolic and energy intake crossover studies

MC4R regulates energy balance; PT-141 research examines feeding suppression and energy expenditure endpoints distinct from GLP-1 pathway tools in comparative metabolic neuroscience experiments. Pairing with melanocortin antagonists confirms receptor mediation.

Molecular Information

Sequence & Chain Summary

Cyclic lactam-bridged heptapeptide melanocortin analog (related to Melanotan II scaffold).

Modification Type

Cyclic structure via lactam bridge; Nle substitution at position 4 typical of melanocortin research peptides.

Structural Notes

PT-141 is a 1025.2 g/mol cyclic peptide requiring correct lactam cyclization verified by mass spectrometry and peptide mapping. Cyclization failure products appear as linear impurities in HPLC. Hydrophobic residues influence solubility requiring dilute acetic acid co-solvent in some reconstitution protocols. Batch-specific molecular characterization—including mass confirmation and purity profiling—is available through COA, LC-MS, HPLC, and NMR documentation supplied with PT-141 (Bremelanotide).

Molecular Formula
C50H68N14O10
Molecular Weight
1025.2 g/mol
Purity Specification
≥98%

Experimental Notes

Stability

Lyophilized PT-141 stable at −20°C protected from moisture. Cyclic peptides may undergo ring-opening degradation in strong alkaline buffers. Reconstituted solutions use promptly or aliquot frozen; minimize pH extremes during storage. Lyophilized PT-141 (Bremelanotide) should be protected from repeated freeze-thaw cycles, moisture, and prolonged exposure to ambient light where applicable. Analytical integrity is best preserved when material is stored under the conditions specified on the certificate of analysis.

Storage Conditions

Store at -20°C. PT-141 (Bremelanotide) is supplied as white lyophilized powder. For long-term archival storage in research inventories, maintain sealed containers with desiccant where recommended and document lot numbers for traceability across experimental runs.

Laboratory Handling

Reconstitute with sterile water optionally containing trace acetic acid for solubility. Protect from light. Use receptor-specific assays to confirm activity batch-to-batch. Reconstitute only with appropriate research-grade solvents compatible with your assay format. Allow vials to reach equilibrium before opening, work under clean bench conditions, and label all working solutions with concentration, date, and researcher ID per institutional SOPs.

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Frequently Asked Questions

Research-focused answers about PT-141 (Bremelanotide). For laboratory use only — not medical advice.

What is PT-141 (Bremelanotide) used for in research?
PT-141 is for melanocortin receptor pharmacology and neuroscience research in qualified laboratories. Not for human sexual dysfunction treatment or recreational use.
How does PT-141 (Bremelanotide) work biologically?
PT-141 activates central MC3R and MC4R, modulating autonomic and behavioral outputs through cAMP and calcium signaling in research models with blood-brain barrier penetration.
What receptors does PT-141 (Bremelanotide) interact with?
Primary targets are melanocortin MC3R and MC4R with lower MC1R activity than melanotan II. Minimal off-target GPCR activation at standard research concentrations.
Is PT-141 (Bremelanotide) stable at room temperature?
Lyophilized PT-141 stable at −20°C protected from moisture. Cyclic peptides may undergo ring-opening degradation in strong alkaline buffers. Reconstituted solutions use promptly or aliquot frozen; minimize pH extremes during storage. For short-term laboratory workflows, minimize time at room temperature and return unused material to recommended storage promptly. PT-141 (Bremelanotide) is not formulated for ambient long-term storage.
What is the recommended storage condition for PT-141 (Bremelanotide)?
Store at -20°C. Store lyophilized material in a dedicated −20°C freezer, protect from moisture ingress, and avoid repeated temperature cycling. Reconstituted solutions should be aliquoted and frozen if not used within the validated window of your internal stability study.