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 2025-08-27 and is reviewed periodically as new material appears.
Early research on PT-141 grew out of work on melanotan II, a related cyclic peptide studied for pigmentation. Investigators observed that centrally acting melanocortin agonists also influenced sexual behaviour in animal models, and the programme shifted toward that endpoint. A nasal formulation was evaluated in clinical trials but showed inconsistent absorption, and later studies used subcutaneous administration instead. Regulatory approval in the United States followed in 2019 for a defined population of premenopausal women with acquired, generalised hypoactive sexual desire disorder. That approval was specific to that group rather than a broad indication.
Bremelanotide acts as a non-selective agonist at melanocortin receptors, with reported activity at MC1R, MC3R, MC4R and MC5R. The proposed basis for its central effects is activation of MC4R populations in the hypothalamus, a region associated with appetite and reproductive signalling. Because the peptide carries a net positive charge and polar side chains, it does not cross biological membranes freely, which is one reason oral administration is not the standard route. Effects generally appear within an hour of parenteral administration and are described as centrally mediated rather than peripheral.
Bremelanotide, developed under the code PT-141, is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone. Its structure is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, with a lactam bridge joining the aspartate and lysine side chains. The molecule has the formula C50H68N14O10 and a monoisotopic mass near 1025 daltons. It is commonly prepared as the acetate salt and appears as a white to off-white lyophilised powder in solid form. The free acid is the pharmacologically relevant species, while the counter-ion improves handling and dissolution.
Regulatory review of bremelanotide concluded in 2019 with approval in the United States for a defined indication in premenopausal women. The reviewed formulation is a single-use prefilled autoinjector given subcutaneously, and its label carries cardiovascular monitoring language tied to blood pressure changes recorded during trials. Availability outside the approving jurisdiction varies, and in several countries the compound remains unapproved or is handled as a prescription-only item. Compounded and research-grade material also circulates, and it differs from the reviewed product in purity, characterization, and chain of custody.
Bremelanotide is a synthetic cyclic heptapeptide developed under the research code PT-141. The code reflects its position in an internal compound series rather than a chemical classification, and the name bremelanotide was later adopted for regulatory filings. Structurally it belongs to the melanocortin peptide family and shares a core sequence motif with alpha-melanocyte-stimulating hormone. The compound is supplied as an acetate salt in aqueous solution for injection. In reference literature it is indexed under both the code and the generic name, a dual listing that can complicate database searches.
Early work on melanocortin analogs in the 1980s and 1990s produced peptides intended to influence pigmentation and appetite. One of these, melanotan II, was observed to affect sexual desire as an incidental finding in self-administration reports. Researchers then pursued analogs with altered receptor selectivity and improved handling characteristics, and PT-141 emerged from that program in the late 1990s. The development path moved from dermatology and metabolism toward a central nervous system application, a shift that shaped both trial designs and the eventual label.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic heptapeptide | Synthetic analogue of alpha-MSH |
| Molecular formula | C50H68N14O10 | Acetate salt form commonly reported |
| Molecular mass | ~1025 Da | Monoisotopic value near 1025.2 |
| Key structural motif | Lactam bridge | Asp side chain to Lys side chain |
| Solid appearance | White to off-white powder | Lyophilised and hygroscopic |
Reconstitution is usually performed with sterile water or a dilute acetic acid solution, and the choice of solvent affects both dissolution speed and final pH. Complete dissolution should be confirmed by visual inspection before any aliquot is taken, since undissolved particles can concentrate in the sampling volume. Repeated freeze-thaw cycles are the most common cause of gradual loss of purity, so dividing a stock into single-use aliquots at the first opportunity is standard practice. Working solutions kept refrigerated are generally used within days rather than weeks.
Identity and purity are established with orthogonal methods rather than a single test. Reverse-phase high-performance liquid chromatography with ultraviolet detection gives a purity figure by area normalization, while mass spectrometry confirms the expected molecular ion. Amino acid analysis or peptide mapping can detect sequence errors that a mass value alone would miss, and residual counterion content is sometimes measured separately. Common impurities include truncated sequences, oxidized residues, and deamidated products; reporting them individually is more informative than a single composite purity number.
How receptor activation translates into a change in desire is not established in detail. Proposed steps include modulation of dopaminergic signalling in reward circuits and downstream effects on autonomic tone. Human data consist mainly of clinical trials measuring self-reported outcomes rather than direct measurements of brain activity or transmitter release. The transient rise in blood pressure sometimes observed after administration is likewise reported consistently but explained only partly by known melanocortin pathways.
Melanocortin receptors form a family of five G-protein-coupled proteins, labelled MC1R through MC5R, that respond to peptides derived from pro-opiomelanocortin. Alpha-melanocyte-stimulating hormone and adrenocorticotropic hormone are the best-known endogenous ligands. The receptors are distributed differently across tissues, so a single agonist can produce effects in the brain, skin, adrenal gland and vasculature. This distribution explains why one peptide can influence both pigmentation and motivated behaviour.
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.
== Mechanism of action == Phenazopyridine's mechanism of action is not well known, and only basic information on its interaction with the body is available. It is known that the chemical has a direct topical analgesic effect on the mucosa lining of the urinary tract. It is rapidly excreted by the kidneys directly into the urine. Hydroxylation is the major form of metabolism in humans, and the azo bond is usually not cleaved. On the order of 65% of an oral dose will be secreted directly into the urine chemically unchanged.
==== Deoxygenated hemoglobin ==== Deoxygenated hemoglobin (deoxyhemoglobin) is the form of hemoglobin without the bound oxygen. The absorption spectra of oxyhemoglobin and deoxyhemoglobin differ. The oxyhemoglobin has significantly lower absorption of the 660 nm wavelength than deoxyhemoglobin, while at 940 nm its absorption is slightly higher. This difference is used for the measurement of the amount of oxygen in a patient's blood by an instrument called a pulse oximeter. This difference also accounts for the presentation of cyanosis, the blue to purplish color that tissues develop during hypoxia. Deoxygenated hemoglobin is paramagnetic; it is weakly attracted to magnetic fields. In contrast, oxygenated hemoglobin exhibits diamagnetism, a weak repulsion from a magnetic field.
== Treatment == The major emphasis of the treatment of JIA is helping the child or young person regain normal levels of physical and social functioning by controlling inflammation and extra-articular symptoms. Clinical remission should be the primary target for all people. Prompt recognition and management is important as early initiation of medication therapy increases the likelihood of a response to first-line treatments and low disability. Consensus treatment guidelines exist for the treatment of JIA. Optimal management of JIA requires a multidisciplinary team working to address the needs of an individual child. Optimizing physical and social functioning is accomplished using non-pharmacological strategies such as physical therapies, pain management strategies, and social supports. Medications are used to control inflammation and reduce or prevent extra-articular symptoms.Non-steroidal anti-inflammatory drugs (NSAIDs) are used for symptomatic relief of joint pain in children with JIA. Disease-modifying antirheumatic drugs (DMARDs), which inhibit specific pathways in the inflammation pathways responsible for JIA, are a primary treatment. Lifelong DMARD treatment is often required, and drug-free remission is exceedingly rare. Oligoarticular JIA (which comprises 40-50% of all JIA cases) by definition involves 4 or fewer joints in the first 6 months of the disease. After 6 months, some cases become polyarticular (involving more than 4 joints). This polyarticular subtype is associated with a lower remission rate with medical therapy.
== Design == The bag is typically partially folded when it is placed in a microwave, and inflates as a result of steam pressure from the heated kernels. Microwave popcorn bags are designed to avoid popped-kernel scorching, an undesirable effect that takes place when popped kernels are heated above 300 °F (150 °C). A susceptor—usually a metalized film laminated onto the paper of the bag—absorbs microwaves and concentrates heat at the film interface, thus ensuring a heat distribution focused on the hard-to-heat flavor coating so that the unpopped kernels are evenly coated prior to popping, thereby ensuring even flavor throughout the product. Some popcorn is flawed and will not pop because of possible damage to the shell, which allows the steam to escape. These unpopped kernels are known as "old men" or "grandpas". An early susceptor popcorn bag design was patented by The American Company General Mills in 1981 (US Patent #4,267,420).
== Sculptra used in cosmetic medicine == Today, Sculptra is used "off label" for other aesthetic enhancements, such as a non-surgical butt lift, alongside a wide range of anatomical regions of the body for overall rejuvenatory effects.
Sources: en.wikipedia.org
=== The Human Betterment Foundation (1929–1942) === The Human Betterment Foundation operated in California from 1929 to 1942. In those years, the foundation specialized in researching eugenic sterilizations effects, providing literary contributions of their findings to the public. The foundation distributed literature, such as this in order to promote the efficacy of sterilizations among socially- Sterilizations during this time were promoted and imposed in state institutions. In the pamphlet, the organization describes that the problem is families living on government assistance or "public charity" use more of the public charity than those families sustaining themselves more by 50 percent. The pamphlet stated that families whose children ended up in state homes were increasingly doubling, at a fast rate. The foundation too states that additional children to the state is a burden, but also that taxation rates were increasing because of more children being in need along with the notion that with more children from unfit parents would increase crime and delinquency rates. And another example of anti-Latino sentiment was with state authorities when dealing with minorities. Immigrants that were feeble minded and at borderline intelligence were of the undesirable type. California's state authorities wrote in a survey conducted by the California State Board of Charities and Corrections that Latinos of low intelligence or mental sanity were of the undesirable types.
The limitation of performing PCR on the isolated fragments is that one must have an idea which genomic region is being targeted in order to generate the correct PCR primers. Sometimes this limitation is circumvented simply by cloning the isolated genomic DNA into a plasmid vector and then using primers that are specific to the cloning region of that vector. Alternatively, when one wants to find where the protein binds on a genome-wide scale, ChIP-sequencing is used and has recently emerged as a standard technology that can localize protein binding sites in a high-throughput, cost-effective fashion, allowing also for the characterization of the cistrome. Previously, DNA microarray was also used (ChIP-on-chip or ChIP-chip).
Ang has the same general catalytic properties as RNase A, it cleaves preferentially on the 3' side of pyrimidines and follows a transphosphorylation/hydrolysis mechanism. Although angiogenin contains many of the same catalytic residues as RNase A, it cleaves standard RNA substrates 105–106 times less efficiently than RNase A. The reason for this inefficiency is due to the 117 residue consisting of a glutamine, which blocks the catalytic site. Removal of this residue through mutation increases the ribonuclease activity between 11 and 30 fold. Despite this apparent weakness, the enzymatic activity of Ang appears to be essential for biological activity: replacements of important catalytic site residues (histidine-13 and histidine-114) invariably diminish both the ribonuclease activity toward tRNA by 10,000 fold and almost abolishes angiogenesis activities completely.
It is announced that folic acid will be added to non-wholemeal wheat flour in the UK to help prevent birth defects. 15 November Data from the Office for National Statistics indicates the UK economy grew by 0.1% in the third quarter of 2024, down from 0.5% in the second quarter. The decrease is attributed to uncertainty over Labour's first budget and continued high interest rates. Myles McHugh, a serving Metropolitan Police officer, is dismissed for gross misconduct after having viewed confidential files related to the murder of Sarah Everard without good cause. A tribunal also finds Hannah Rebbeck and Mark Harper guilty of gross misconduct for the same reason. Rebbeck, who has already left the police, would have been dismissed if she were still serving, while Harper is given a final written warning. The Met Office issues a weather warning for snow and ice for southern Scotland and northern England, beginning on 17 November. Figures indicate the cost of mortgages has risen despite a cut in interest rates, with an average two-year fixed term mortgage at 5.5%. 16 November – Snow and ice warnings are issued by the Met Office for late Sunday 17 November through to Tuesday 19 November, as cold Arctic air spreads across the United Kingdom. 17 November The UK government gives more details on a £1bn investment plan to bring what it calls a "London-style" bus service to the rest of England. Tickets for the 2025 Glastonbury Festival go on sale at 9am, and sell out in 35 minutes.
Sources: en.wikipedia.org
PT-141 was the development code used for bremelanotide during its preclinical and early clinical programme. The peptide is now generally referred to by its international nonproprietary name.
The two compounds share the same cyclic core and are both non-selective melanocortin agonists. They differ chiefly at the C-terminus, where bremelanotide carries a free carboxylic acid and melanotan II a terminal amide.
Receptor binding profiles are well characterised in vitro, but the downstream pathway linking MC4R activation to behavioural effects is not fully mapped. Several intermediate neural circuits have been proposed without definitive confirmation.
PT-141 was the internal development code assigned to bremelanotide during preclinical research. Reference sources sometimes index the peptide under the code rather than the generic name. The two terms describe the same molecule.