PT-141

PT-141 (Bremelanotide) — melanocortin receptor agonist for research

PT-141, also known as bremelanotide, is a cyclic heptapeptide with agonist activity at MC3R and MC4R melanocortin receptors. Structurally, it is derived from Melanotan II, from which it differs in higher affinity for the MC4R receptor with limited activity towards MC1R. In preclinical studies, PT-141 is a tool for analyzing melanocortin signaling in models of the central nervous system. The product is intended solely for research purposes (Research Use Only) – it is not a medicinal product. Browse available PT-141 variants from One Peptides.

What is PT-141?

PT-141 (bremelanotide) is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, belonging to the class of melanocortin receptor agonists. Its history dates back to research on alpha-MSH (melanocyte-stimulating hormone) analogues conducted at the University of Arizona by the team of Victor Hruby and Mac Hadley in the 1980s and 1990s.

PT-141 was created as a metabolite and structural analogue of Melanotan II (MT-II), from which it differs in its receptor selectivity profile. While MT-II has activity on multiple melanocortin receptor subtypes — including MC1R (responsible for pigmentation in cell models) — PT-141 has preferential affinity for MC3R and MC4R receptors, located primarily in structures of the central nervous system.

The melanocortin system includes five receptor subtypes (MC1R-MC5R), endogenous ligands (alpha-MSH, beta-MSH, gamma-MSH, ACTH) and an endogenous antagonist (AgRP). In preclinical studies, PT-141 is used as a pharmacological tool to analyze the role of the MC4R receptor in animal models – in particular in the context of signaling in the hypothalamus and other CNS structures. Studies in rodent models have provided observations regarding the effects of MC4R activation on various physiological functions regulated by this pathway.

PT-141 variants available

The product has a Certificate of Analysis (CoA) documenting the purity and identity of the substance. Detailed parameters can be found on the product card.

Which PT-141 variant should you choose?

PT-141 (Bremelanotide) is available from One Peptides in the form of a lyophilisate containing 10 mg of substance per vial. This amount allows for both in vitro receptor binding experiments and studies on in vivo animal models analyzing melanocortin signaling.

When planning comparative experiments with Melanotan II, it is worth taking into account the differences in the receptor selectivity of both peptides – PT-141 has a higher affinity for MC4R, while MT-II activates a broader spectrum of melanocortin receptors, including MC1R.

How does PT-141 differ from similar peptides?

PT-141 vs Melanotan II

PT-141 and Melanotan II are structurally related — PT-141 is a cyclic metabolite of MT-II — but they differ in their receptor selectivity profile. Melanotan II activates a wide spectrum of melanocortin receptors, including MC1R, which in melanocyte cell models is associated with pigmentation processes. PT-141 shows preferential affinity for MC3R and MC4R with significantly reduced activity towards MC1R. This difference in selectivity makes PT-141 a more precise tool for studying MC4R signaling in CNS models, while MT-II is applicable in studies also involving the pigmentation pathway. More about Melanotan in the category Melanotan.

PT-141 vs Kisspeptin

PT-141 and kisspeptin act on completely different regulatory axes. PT-141 is an agonist of MC3R/MC4R melanocortin receptors – elements of the melanocortin system in the CNS. Kisspeptin, on the other hand, acts through the KISS1R receptor (GPR54) and is a master regulator of the GnRH (gonadotropin releasing hormone) axis, controlling the secretion of gonadotropins in neuroendocrine models. Although both peptides are studied in the context of hypothalamus-regulated functions, their molecular targets, receptors and signaling cascades do not overlap. These are complementary tools, useful in various research paradigms. More about kisspeptin in the category Kisspeptin.

FAQ — Frequently asked questions

1. Is PT-141 from the One Peptides offer a medicinal product?
NO. PT-141 (bremelanotide) offered by One Peptides is a chemical substance intended solely for research purposes (Research Use Only). It is not a medicinal product and is not intended for use in humans or animals outside the context of approved research protocols.

2. What is the difference between PT-141 and Melanotan II at the molecular level?
PT-141 is a cyclic heptapeptide derived from Melanotan II, but it differs from it in its receptor selectivity profile. PT-141 has preferential affinity for MC3R and MC4R receptors, whereas MT-II activates a broader spectrum of melanocortin receptors, including MC1R. Structurally, PT-141 lacks the linear N-terminal tail present in MT-II.

3. What melanocortin receptors are targeted by PT-141?
PT-141 acts primarily as an agonist of MC3R and MC4R receptors. The MC4R receptor is expressed primarily in structures of the central nervous system, including the hypothalamus, amygdala and brainstem. The MC3R receptor is also present in the CNS and peripheral tissues. The activity of PT-141 against MC1R (pigmentation receptor) and MC5R is significantly reduced compared to MT-II.

4. How to store PT-141 in lyophilized form?
PT-141 lyophilisate should be stored at -20 degrees Celsius, in the original packaging, away from light and moisture. After reconstitution, the working solution should be stored at 2-8 degrees Celsius and used within the time frame consistent with the research protocol.

5. What is the melanocortin system tested with PT-141?
The melanocortin system is a signaling network that includes five receptor subtypes (MC1R-MC5R), endogenous agonist peptides (proopiomelanocortin derivatives – alpha-MSH, beta-MSH, gamma-MSH, ACTH) and an endogenous antagonist – AgRP protein. This system is present in the CNS and peripheral tissues, and PT-141 serves as a synthetic tool to selectively activate MC3R/MC4R within this system.

Quality and standards at One Peptides

Each batch of PT-141 in the One Peptides offer is analyzed using high-performance liquid chromatography (HPLC) and mass spectrometry (MS), which helps confirm the purity and identity of the peptide. Each product is accompanied by a certificate of analysis (CoA) and a safety data sheet (SDS). Quality documentation is available for download from the product card.