Melanocortin receptor is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-04-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H68N14O10 | Free base; the drug product is formulated as an acetate salt |
| Molar mass | About 1025 g/mol | Calculated for the free base |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| CAS Registry Number | 189691-06-3 | Common listing for the free base |
| Typical storage | -20 °C, desiccated, protected from light | Repeated freeze-thaw cycles are best avoided |
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.
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.
In a 2016 survey conducted by the Varkey Foundation and Populus, the question of whether or not those 15 to 21 favored legal migration received mixed responses. In the United States, that margin of support was 16%, higher than the global average of 8%. (See chart above.) According to Gallup, Americans aged 18 to 34 are more likely to view immigration as a "good thing" than their elders. By 2024, a clear majority of young adults supported increased patrols along the American-Mexican border to combat illegal immigration into the United States.
The School of Clinical Medicine is the medical school of the University of Cambridge in England. The Cambridge Graduate Course in Medicine (A101) is the most competitive course offered by the university and in the UK, and is among the most competitive medical programmes for entry in the world. The school is located alongside Addenbrooke's Hospital and other institutions in multiple buildings across the Cambridge Biomedical Campus.
The connecting peptide, or C-peptide, is a short 31-amino-acid polypeptide that connects insulin's A-chain to its B-chain in the proinsulin molecule. In the context of diabetes or hypoglycemia, a measurement of C-peptide blood serum levels can be used to distinguish between different conditions with similar clinical features. In the insulin synthesis pathway, first preproinsulin is translocated into the endoplasmic reticulum of beta cells of the pancreas as one polypeptide comprising the regions of the A-chain, C-peptide, B-chain, and signal sequence. The signal sequence is cleaved from the N-terminus of the peptide by a signal peptidase, leaving proinsulin. After proinsulin is packaged into vesicles in the Golgi apparatus (beta-granules), the C-peptide is removed, leaving the A-chain and B-chain bound together by disulfide bonds, that constitute the insulin molecule. C-peptide has virtually no affinity for the insulin receptor, however, it is known to promote the activity of at least two enzymes - the sodium–potassium pump and nitric oxide synthase - downstream of binding to a membrane structure (presumably a G protein-coupled receptor). Nevertheless, the physiological significance of these effects of C-peptide is unresolved.
=== Misuse potential === Baclofen can produce a feeling of well-being, relaxation, and mild euphoria. Baclofen, at standard dosing, does not appear to possess addictive properties, and has not been associated with any degree of drug craving.
Sources: en.wikipedia.org
Despite their cultural depictions as "swimming dinosaurs", mosasaurs, ichthyosaurs, plesiosaurs, and other aquatic Mesozoic diapsids were not dinosaurs. Mosasaurs were actually lizards, and ichthyosaurs and plesiosaurs were even more distantly related to dinosaurs. Though some dinosaurs were or are semiaquatic (Hesperornis, Spinosaurus, auks, penguins), none are known to have been fully marine. Pterosaurs (informally called pterodactyls) are often called "flying dinosaurs" by popular media and the general public, but while pterosaurs were closely related to dinosaurs, dinosaurs are defined as the descendants of the last common ancestor of the Saurischia and the Ornithischia, which excludes the pterosaurs. Dimetrodon is often mistakenly called a dinosaur or considered to be a contemporary of dinosaurs in popular culture, but it became extinct some 40 million years before the first appearance of dinosaurs. Being a synapsid, Dimetrodon is actually more closely related to mammals than to dinosaurs, lizards, or other diapsids. Humans and non-avian dinosaurs did not coexist at any point, although humans and avian dinosaurs currently coexist. The last of the non-avian dinosaurs died 66 million years ago in the Cretaceous–Paleogene extinction event while the earliest members of the genus Homo (humans) evolved between 2.3 and 2.4 million years ago. With the exception of a tiny amount of the world's coal, fossil fuels such as petroleum and coal do not originate from dinosaur fossils.
=== Pharmacokinetics === Desloratadine is well absorbed from the gut and reaches highest blood plasma concentrations after about three hours. In the bloodstream, 83 to 87% of the substance are bound to plasma proteins. Desloratadine is metabolized to 3-hydroxydesloratadine in a three-step sequence in normal metabolizers. First, N-glucuronidation of desloratadine by UGT2B10; then, 3-hydroxylation of desloratadine N-glucuronide by CYP2C8; and finally, a non-enzymatic deconjugation of 3-hydroxydesloratadine N-glucuronide. Both desloratadine and 3-hydroxydesloratadine are eliminated via urine and feces with a half-life of 27 hours in normal metabolizers.
In March 2001 the license for Trovan was withdrawn in Europe, by the European Commission due to liver toxicity and some deaths. In June 2010, the US Supreme Court rejected Pfizer's appeal against a ruling allowing lawsuits by the Nigerian families to proceed. In December 2010, the United States diplomatic cables leak indicated that Pfizer hired investigators to find evidence of corruption against Nigerian attorney general Michael Aondoakaa to persuade him to drop legal action. The Washington Post reporter Joe Stephens, who helped break the story in 2000, called these actions "dangerously close to blackmail". In response, the company released a press statement describing the allegations as "preposterous" and saying that it acted in good faith. Aondoakka, who had allegedly demanded bribes from Pfizer in return for a settlement of the case, was declared unfit for office and had his U.S. visa revoked in association with corruption charges in 2010. The lawsuits were eventually settled out of court. Pfizer committed to paying US$35 million "to compensate the families of children in the study", another $30 million to "support healthcare initiatives in Kano", and $10 million to cover legal costs. Payouts began in 2011.
Sources: en.wikipedia.org
PT-141 is a research code for bremelanotide, a cyclic peptide that activates melanocortin receptors. It was developed for sexual dysfunction and later approved under a brand name as a subcutaneous injection. The same code is widely used by suppliers selling non-pharmaceutical material.
Both are synthetic melanocortin agonists and share a similar peptide backbone, but they are distinct molecules with different receptor profiles. Melanotan II was never approved as a medicine, whereas bremelanotide was. Findings about one compound should not be transferred to the other without direct evidence.
It is typically distributed as a lyophilized powder in sealed vials, sometimes with a separate solvent. Purity statements usually originate from the supplier rather than an independent laboratory. Storage recommendations vary between vendors, which makes comparison across sources difficult.
It belongs to the melanocortin receptor agonist family of peptides. Its cyclic structure distinguishes it from linear peptides and shapes its receptor binding profile.