The short version of Melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-08 and is reviewed periodically as new material appears.
Across literature and commercial listings, the substance appears under several names, including bremelanotide, PT-141, and various brand designations. A CAS registry number provides a unique identifier for the compound, aiding retrieval from chemical databases. Synonym lists may also contain early development codes and descriptive chemical names. When consulting sources, researchers need to confirm that the cited names refer to the same molecular structure to avoid confusion. Naming consistency matters especially when comparing analytical data across publications.
PT-141 is a synthetic cyclic heptapeptide whose development code is bremelanotide. It belongs to the class of melanocortin receptor agonists and acts by mimicking endogenous peptide hormones. The compound originated from research on melanotan II, where investigators exploring derivatives found distinct pharmacological features. Unlike the parent compound, PT-141 showed effects on pathways related to sexual desire and function in early studies, prompting its development as a separate candidate. Its molecular design aimed to separate receptor activity from pigmentary effects.
The molecular backbone consists of seven amino acid residues joined into a ring through a disulfide bridge. This cyclic conformation is critical for receptor binding. The sequence includes an acetylated N-terminus and an amidated C-terminus, modifications that improve resistance to enzymatic breakdown. One residue is in the D-configuration, a feature that further stabilizes the peptide against protease activity. Together, the ring structure and specific stereochemistry determine selectivity among melanocortin receptor subtypes.
Regulatory status varies by jurisdiction, where approved prescription products, compounded preparations and research-grade material are treated as distinct categories with different documentation requirements. Suppliers of research material commonly issue a certificate of analysis listing purity, identity and sometimes endotoxin content. Independent verification by a third-party laboratory is often recommended because self-reported figures are difficult to check. Literature discussions usually state the source, purity and storage conditions of the material used, since these details affect reproducibility. Analysts note that a reported purity figure does not by itself describe biological activity.
Lyophilised peptide is generally held below minus twenty degrees Celsius, protected from light and moisture, because hydrolysis and oxidation accumulate faster at ambient temperature. Once reconstituted, solutions are typically kept between two and eight degrees Celsius and used within a short window defined by the supplier. Repeated freeze-thaw cycles are avoided since they promote aggregation and loss of soluble material. Container material matters as well, because peptides adsorb to certain plastics and glass surfaces at low concentration. Stability figures supplied by a vendor apply only to the specific lot and buffer that were tested.
Identity and purity are usually established with reversed-phase high-performance liquid chromatography combined with mass spectrometry. A gradient of water and acetonitrile containing trifluoroacetic acid is a common mobile phase, and ultraviolet detection near 214 nanometres responds to the peptide backbone. Mass spectrometry confirms the expected molecular mass and helps reveal truncation or oxidation products. Purity is reported as a peak-area percentage, a figure that depends on the wavelength and gradient used, so values from different laboratories are not always directly comparable. Peptide mapping and amino acid analysis provide additional confirmation when required.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic peptide | Melanocortin receptor agonist family |
| Molecular weight | Approximately 1025 Da | Free base form |
| Appearance | White to off-white powder | Lyophilized product |
| Solubility | Soluble in water | Also dissolves in polar organic solvents |
| Storage temperature | -20 degrees Celsius | Dry and protected from light |
Outside the approved product, bremelanotide circulates as a research chemical sold by peptide vendors, often labelled PT-141. Such material is not manufactured under pharmaceutical quality standards, and independent testing has repeatedly found content that differs from the label. Analytical certificates supplied with a purchase are not strong evidence of purity because they are usually generated by the seller. Online discussion tends to blur the distinction between the approved drug and unregulated powder, which complicates interpretation of reported experiences.
PT-141 is the original development code for bremelanotide, a synthetic peptide first studied as a potential tanning and sexual-response agent in the 1990s. Researchers at a small American biotechnology firm designed it as a shortened analogue of melanotan II, which itself came from work on alpha-melanocyte-stimulating hormone. Early screening focused on pigmentation, but behavioural observations in animal models redirected attention toward sexual motivation. That shift made PT-141 one of the first melanocortin compounds investigated specifically for effects on desire rather than on skin colour.
Clinical development proceeded through two routes of administration. An intranasal formulation advanced first, but variable absorption and tolerability problems led to a switch to subcutaneous injection. The United States Food and Drug Administration approved the subcutaneous product in 2019 for hypoactive sexual desire disorder in premenopausal women. Marketing rights subsequently changed hands, and commercial availability has fluctuated since approval. Use in men, in postmenopausal women, and in combination with other agents remains outside the approved label.
=== Inlet for liquids === A now well established setup for the controlled evaporation and subsequent analysis of liquids with PTR-MS has been published in 2013 by Fischer et al. As the authors saw the main application of their setup in the calibration of PTR-MS instruments via aqueous standards, they named it "Liquid Calibration Unit (LCU)". The LCU sprays a liquid standard into a gas stream at well-defined flow rates via a purpose-built nebulizer (optimized for reduced probability of clogging and high tolerance to salts in the liquid). The resulting micro-droplets are injected into a heated (> 100 °C) evaporation chamber. This concept offers two main advantages: (i) the evaporation of compounds is enhanced by the enlarged surface area of the droplets and (ii) compounds which are dissociated in water, such as acids (or bases), experience a shift in pH value when the water evaporates from a droplet. This in turn reduces dissociation and supports total evaporation of the compound. The resulting continuous gas flow containing the analytes can be directly introduced into a PTR-MS instrument for analysis.
Luis Moroder (6 December 1940 – 18 May 2024) was an Italian peptide chemist, who pioneered research on the interactions between peptide hormones and cell membrane-bound hormone receptors. He later expanded this research to other biological systems of medical relevance such as protein inhibitors, collagens, and synthetic proteins. A hallmark of his research is interdisciplinarity as reflected in his use and development of methods in organic chemistry, biophysics and molecular biology. He was a co-editor of the five-volume Houben-Weyl, Methods of Organic Chemistry, Synthesis of Peptides and Peptidomimetics. From 2008 he was the editor-in-chief of the Journal of Peptide Science, the official journal of the European Peptide Society.
For an intravenously administered drug, the bioavailability F will equal 1, since the drug is directly introduced to the bloodstream. If the patient requires an oral dose, bioavailability will be less than 1 (depending upon absorption, first pass metabolism etc.), requiring a larger loading dose.
=== Organic synthesis === Acetonitrile is a common two-carbon building block in organic synthesis of many useful chemicals, including acetamidine hydrochloride, thiamine, and 1-naphthaleneacetic acid, along with more complex nitriles. Its reaction with cyanogen chloride affords malononitrile.
GABA, also known as gamma-aminobutyric acid or γ-aminobutyric acid, is the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system. GABA is sold as a dietary supplement in many countries. It has been traditionally thought that exogenous GABA (i.e., taken as a supplement) does not cross the blood–brain barrier, but data obtained from more recent research (2010s) in rats describes the notion as being unclear. The carboxylate form of GABA is γ-aminobutyrate.
Sources: en.wikipedia.org
The UNESCO International Bioethics Committee recommended a precautionary global moratorium on the creation of mirror-image organisms, and the UK Government Office for Science held an expert roundtable that recommended "prevent[ing] the development of replicating mirror organisms." Several philanthropic funders have also stated that they will not fund research with the goal of creating mirror-image organisms, including Renaissance Philanthropy. In 2026, the UN Scientific Advisory Board called for "proactive multilateral action, such as a dedicated global forum, to define clear 'red lines', strengthen safety and monitoring practices, and establish responsible policy well before mirror life becomes feasible", and Chinese and US policy research organizations issued a joint statement calling for "national and international frameworks to guard against the risks posed by mirror life, reaffirming the shared view that such organisms should never be created." Some scientists and scholars have argued that concerns about mirror-image life are theoretical and/or that bans on research and funding bans are premature. Others have argued that the immune system might be able to recognize mirror versions of a certain type of biomolecule. Some scientists have proposed developing guidelines for synthetic biological entities regardless of their chirality.
Besides inhibiting human acetylcholinesterase (although to a lesser degree than the insect enzyme), carbamate insecticides also target human melatonin receptors. The human health effects of carbamates are well documented in the list of known endocrine disruptor compounds. Clinical effects of carbamate exposure can vary from slightly toxic to highly toxic depending on a variety of factors including such as dose and route of exposure with ingestion and inhalation resulting in the most rapid clinical effects. These clinical manifestations of carbamate intoxication are muscarinic signs, nicotinic signs, and in rare cases central nervous system signs.
== Function and mechanism == "SARS" and its enzyme product seryl-tRNA synthetase are involved in protein translation; specifically, seryl-tRNA synthetase catalyses the transfer of L-serine to tRNA (Ser). The cytosolic enzyme recognises its cognate tRNA species and binds with a high level of specificity, allowing the accurate interaction between corresponding codons and anticodons on mRNA and tRNA during protein translation.
The GlyR agonism of sarcosine is relevant at concentrations frequently used in experimental settings (0.5–2 mM), complicating the pharmacological interpretation. Aside from effects on glycine-related structures and NMDA receptors, sarcosine has been shown to modulate AMPA receptor function and downstream mTOR signalling in rodent models of depression. Long-term sarcosine administration (21 days) ameliorated chronic unpredictable stress-induced depressive behaviour in rats In the rat forced swim test, a single systemic dose of sarcosine produced rapid antidepressant-like effects accompanied by increased phosphorylation of mTOR and its upstream kinases in the hippocampus, and these behavioural and molecular effects were abolished by pretreatment with the AMPA receptor antagonist NBQX or the mTOR inhibitor rapamycin. Sarcosine also increased phosphorylation of the GluR1 subunit at the protein kinase A site Ser845, a change commonly interpreted as enhanced AMPA receptor membrane insertion. Cryo-EM study published in 2025 resolved the structure of human GlyT1 in complex with sarcosine at 2.8 Å resolution, revealing the transporter in an occluded conformation.
In 1913, chemists Frederick Soddy and Kasimir Fajans independently observed that alpha decay caused atoms to move down two places on the periodic table, while the loss of two beta particles restored it to its original position. Under the resulting reorganisation of the periodic table, radium was placed in group II, actinium in group III, thorium in group IV and uranium in group VI. This left a gap between thorium and uranium. Soddy predicted that this unknown element, which he referred to (after Dmitri Mendeleev) as "ekatantalium", would be an alpha emitter with chemical properties similar to tantalum. It was not long before Fajans and Oswald Helmuth Göhring discovered it as a decay product of a beta-emitting product of thorium. Based on the radioactive displacement law of Fajans and Soddy, this was an isotope of the missing element, which they named "brevium" after its short half-life. However, it was a beta emitter, and therefore could not be the mother isotope of actinium. This had to be another isotope of the same element. Hahn and Meitner set out to find the missing mother isotope. They developed a new technique for separating the tantalum group from pitchblende, which they hoped would speed the isolation of the new isotope. The work was interrupted by the First World War. Meitner became an X-ray nurse, working in Austrian Army hospitals, but she returned to the Kaiser Wilhelm Institute in October 1916.
Sources: en.wikipedia.org
Stuart Wright, Dancer's Guide to Injuries of the Lower Extremity (New York: Cornwall Books, 1985), p. 14. Swischuk, Leornard E. "Doing the Splits: Heard A Pop--Cannot Walk." Pediatric Emergency Care 23.11 (2007): 842-3. Web. 8 Sep. 2010. <http://ovidsp.tx.ovid.com>.
=== Family === U7-CNTX-Pn1a is considered as a member of the CSTX family. Although this family mainly contains toxins found in the venom of Cupiennius salei, U7-CNTX-Pn1a is also included because of its highly similar disulfide bond structure.
=== Labeling === For US food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value. For vitamin B6 labeling purposes 100% of the Daily Value was 2.0 mg, but as of May 27, 2016, it was revised to 1.7 mg to bring it into agreement with the adult RDA. A table of the old and new adult daily values is provided at Reference Daily Intake.
==== MeSH D13.570.583 – purine nucleosides ==== MeSH D13.570.583.138 – adenosine MeSH D13.570.583.138.025 – adenosine-5'-(n-ethylcarboxamide) MeSH D13.570.583.138.240 – s-adenosylhomocysteine MeSH D13.570.583.138.264 – s-adenosylmethionine MeSH D13.570.583.138.300 – 2-chloroadenosine MeSH D13.570.583.138.300.200 – cladribine MeSH D13.570.583.138.325 – deoxyadenosines MeSH D13.570.583.138.325.075 – cladribine MeSH D13.570.583.138.325.105 – dideoxyadenosine MeSH D13.570.583.138.325.800 – puromycin aminonucleoside MeSH D13.570.583.138.500 – isopentenyladenosine MeSH D13.570.583.138.630 – phenylisopropyladenosine MeSH D13.570.583.138.711 – puromycin MeSH D13.570.583.138.711.650 – puromycin aminonucleoside MeSH D13.570.583.138.900 – vidarabine MeSH D13.570.583.454 – guanosine MeSH D13.570.583.454.240 – deoxyguanosine MeSH D13.570.583.454.500 – nucleoside q MeSH D13.570.583.616 – inosine MeSH D13.570.583.616.130 – didanosine MeSH D13.570.583.616.450 – inosine pranobex MeSH D13.570.583.616.900 – thioinosine MeSH D13.570.583.616.900.500 – methylthioinosine MeSH D13.570.583.910 – tubercidin
In contrast to MRI, structural biology studies do not directly generate an image, but rely on complex computer calculations to generate three-dimensional molecular models. Currently most samples are examined in a solution in water, but methods are being developed to also work with solid samples. Data collection relies on placing the sample inside a powerful magnet, sending radio frequency signals through the sample, and measuring the absorption of those signals. Depending on the environment of atoms within the protein, the nuclei of individual atoms will absorb different frequencies of radio signals. Furthermore, the absorption signals of different nuclei may be perturbed by adjacent nuclei. This information can be used to determine the distance between nuclei. These distances in turn can be used to determine the overall structure of the protein. A typical study might involve how two proteins interact with each other, possibly with a view to developing small molecules that can be used to probe the normal biology of the interaction ("chemical biology") or to provide possible leads for pharmaceutical use (drug development). Frequently, the interacting pair of proteins may have been identified by studies of human genetics, indicating the interaction can be disrupted by unfavorable mutations, or they may play a key role in the normal biology of a "model" organism like the fruit fly, yeast, the worm C. elegans, or mice. To prepare a sample, methods of molecular biology are typically used to make quantities of protein by recombinant expression and purification from bacteria.
Sources: en.wikipedia.org
It belongs to the melanocortin receptor agonist family of peptides. Its cyclic structure distinguishes it from linear peptides and shapes its receptor binding profile.
It emerged from research on melanotan II. Investigators exploring derivatives observed distinct pharmacological features related to sexual function.
Common names include bremelanotide and PT-141. Chemical databases may also list early development codes and descriptive names.
Purity is normally expressed as a percentage of total peak area from a chromatographic run. The value depends on the column, gradient and detection wavelength chosen. Results generated under different conditions are therefore not always interchangeable.