Everything below concerns receptor agonist. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Compared with melanotan II, bremelanotide is a smaller cyclic peptide with a more constrained backbone, which affects receptor selectivity and metabolic stability. Published descriptions give a plasma half-life on the order of a few hours after subcutaneous administration, with elimination through hepatic and renal routes and limited plasma protein binding. Central access is inferred from effects observed in animal models, although direct measurement in humans is limited. Handling and storage requirements follow from the peptide backbone, which is susceptible to hydrolysis and oxidation.
The melanocortin system comprises five G protein-coupled receptors, designated MC1 through MC5, that signal mainly through cyclic AMP accumulation. MC1R and MC2R are associated with pigmentation and adrenal steroid production, while MC3R and MC4R are expressed in the central nervous system and influence energy balance and behavior. MC5R appears in exocrine tissues. Natural agonists include alpha-melanocyte-stimulating hormone and adrenocorticotropic hormone, and endogenous antagonists such as agouti-related protein modulate the same sites. This receptor family provides the framework within which bremelanotide activity is described.
| 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 |
From a pharmacokinetic standpoint, the peptide is usually delivered by injection because oral bioavailability is very low; proteases in the digestive tract degrade it rapidly. After subcutaneous administration, plasma concentrations reach a peak within roughly one hour. Its elimination half-life is relatively short, with most reports placing it in the range of a few hours. Nasal formulations have also been examined, though absorption varies widely between individuals. Metabolism proceeds mainly through peptidase cleavage, and the resulting products are excreted by the kidneys.
PT-141 initiates cellular signaling by binding to specific subtypes within the melanocortin receptor family. These receptors belong to the G protein-coupled receptor superfamily, and activation raises intracellular cyclic adenosine monophosphate levels. This cascade ultimately influences neuronal circuits in the central nervous system that are associated with sexual desire and arousal. Research indicates the compound's action concentrates in hypothalamic regions rather than peripheral tissues, which helps explain some observed pharmacological features. The selectivity of receptor binding underlies its functional differences.
Bremelanotide is a moderately large peptide with a molecular mass near 1025 daltons. In lyophilised form it appears as a white to off-white powder and is freely soluble in water and other polar solvents. The intact lactam ring is essential for receptor affinity, while linearised fragments bind far more weakly. Solutions are sensitive to extremes of pH and to prolonged exposure to light and heat, so handling typically involves buffered conditions and cold storage. Its short plasma half-life reflects rapid distribution and clearance rather than chemical breakdown inside the vial.
Development of the peptide passed through several delivery formats, including an intranasal version tested in early trials and an injectable version that entered later clinical study. Regulatory approval for a subcutaneous product in the United States was granted in 2019 after review of controlled trials in premenopausal women. Outside the clinic, the compound circulates in research and non-pharmaceutical markets under its code name, where identity and purity vary considerably between suppliers. Synonyms appearing across technical literature include bremelanotide, PT-141, and Palatin 141.
PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide developed as a melanocortin receptor agonist. The peptide contains seven amino acids with an internal lactam bridge that constrains the backbone into a stable ring. Cyclisation of this kind improves resistance to enzymatic degradation relative to linear analogues. The compound was first explored for effects on melanin production, because several melanocortin receptors influence pigmentation. Its later association with sexual desire emerged from observations made during that early work, and the molecule became the subject of a separate development programme.
Lyophilized peptide arrives as a white to off-white cake or powder and is normally held at minus twenty degrees Celsius or colder for extended periods. Short-term bench work at ambient temperature is tolerable for minutes, not hours, because the solid is hygroscopic and picks up moisture that promotes hydrolysis. Vials should stay in a desiccator or a sealed bag with desiccant, protected from light, since aromatic residues in the sequence are susceptible to photo-oxidation. Inventory records that note arrival date and storage location reduce the chance of using degraded material.
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.
==== Other constituents ==== Soy contains isoflavones—polyphenolic compounds, produced by legumes including peanuts and chickpeas. Isoflavones are closely related to flavonoids found in other plants, vegetables and flowers. Soy contains the phytoestrogen coumestans, also are found in beans and split-peas, with the best sources being alfalfa, clover, and soybean sprouts. Coumestrol, an isoflavone coumarin derivative, is the only coumestan in foods. Saponins, a class of natural surfactants (soaps), are sterols that are present in small amounts in various plant foods, including soybeans, other legumes, and cereals, such as oats.
anhydrous Having or containing no water molecules, referring especially to water of hydration. Because many processes in chemistry are impeded in the presence of water, it is often of critical importance that water-free reagents and techniques are used. Anhydrous compounds tend to gradually absorb water from the atmosphere. Contrast hydrous.
Conservationist, Sylvan Height's Waterfowl Park and EcoCenter, North Carolina, United States of America. For services to Global Wildlife Conservation of Water Birds. Dr. Robert Murray Lyman. Author of Military History; Trustee and former Chairman, the Kohima Educational Trust. For services to Military History and to Charitable Work in Nagaland, Northeast India. Steven Lawrie Lynch. Lately Managing Director, British Chamber of Commerce, Beijing, China. For services to the British Business Community in China. Mary Dionesse Martin. Board Member and Honorary Treasurer, Cheshire Homes, Mbabane, Eswatini. For services to People with Disabilities in Eswatini. Sharon Marie Martin. Educator (retired), the Government's Public Education System, Cayman Islands. For services to Education and to the community in the Cayman Islands. Justin Owen McPhee. Lately Commanding Officer, Falkland Islands Defence Force. For services to Defence in the Falkland Islands. Diane Miles. Co-Founder and Trustee, Afrikaya charity, The Gambia. For services to Education in The Gambia. John Charles Mitchell. Head of Roamer Team, Eastern European and Central Asia Directorate, Foreign, Commonwealth and Development Office. For services to British Foreign Policy. John Gabriel Monaghan. Station Manager (retired), Devon and Somerset Fire and Rescue Service; Founder and Project Manager, Fire Aid Nepal. For services to Emergency and Disaster Response and to local Communities in Nepal. Calypso Mabel Nash. Lately Acting Head of Chancery, British Embassy Tehran, Iran. For services to British Foreign Policy.
Clinical pathologists may assist physicians in interpreting complex tests such as platelet aggregometry, hemoglobin or serum protein electrophoresis, or coagulation profiles. If interfering substances are suspected, they may recommend alternate test methods. For example, hemolysis, icterus, lipemia, or heterophile antibodies may confound results obtained by traditional methods such as ion-selective electrodes, enzymatic assays or immunoassays. Alternate methods such as blood gas analysers, point-of-care testing or mass spectrometry may help resolve the clinical question.
== Role in Peptide Synthesis == The use of Fmoc as a temporary protecting group for amine at the N-terminus in solid phase synthesis is very widespread for Fmoc/tBu approach, because its removal with piperidine does not disturb the acid-labile linker between the peptide and the resin. A typical SPPS Fmoc deprotection is performed with a solution of 20% piperidine in N,N-dimethylformamide (DMF).
Sources: en.wikipedia.org
=== Eye drops vs. other treatments === The TAGS randomised controlled trial investigated whether eye drops or trabeculectomy is more effective in treating advanced primary open-angle glaucoma. After two years, researchers found that vision and quality of life are similar in both treatments. At the same time, eye pressure was lower in people who underwent surgery, and in the long run, surgery is more cost-effective. The LiGHT trial compared the effectiveness of eye drops and selective laser trabeculoplasty for open-angle glaucoma. Both contributed to a similar quality of life, but most people undergoing laser treatment were able to stop using eye drops. Laser trabeculoplasty was also shown to be more cost-effective.
Type VII was the first recessive OI type confirmed, initially found among First Nations people in Quebec. Type VIII – OI caused by a mutation in the gene LEPRE1 on chromosome 1p34.2; clinically similar to OI types II and III, depending on affected individual. Type IX – OI caused by homozygous or compound heterozygous mutation in the PPIB gene on chromosome 15q22.31. Type X – OI caused by homozygous mutation in the SERPINH1 gene on chromosome 11q13. Type XI – OI caused by mutations in FKBP10 on chromosome 17q21. The mutations cause a decrease in the secretion of trimeric procollagen molecules. Other mutations in this gene can cause autosomal recessive Bruck syndrome, which is similar to OI. Type XII – OI caused by a frameshift mutation in SP7 on chromosome 12q13.13. This mutation causes bone deformities, fractures, and delayed tooth eruption. Type XIII – OI caused by a mutation in the bone morphogenetic protein 1 (BMP1) gene on chromosome 8p21.3. This mutation causes recurrent fractures, high bone mass, and hypermobile joints. Type XIV – OI caused by mutations in the TMEM38B gene on chromosome 9q31.2. This mutation causes recurrent fractures and osteopenia, although the disease trajectory is highly variable. Type XV – OI caused by homozygous or compound heterozygous mutations in the WNT1 gene on chromosome 12q13.12. It is autosomal recessive. Type XVI – OI caused by mutations in the CREB3L1 gene on chromosome 11p11.2.
Stirring of a given sample of amylose is said to form fibrillar crystals which are said to precipitate out of the mother liquor. These long fibrils can be imaged using electron microscopy revealing transverse striations resembling a shish-kebab. Amylose fibrils are categorized with having one of two morphologies: ones with small rodlike fibrils and others with lath-shaped crystals.
No flerovium atoms were detected; this was thought to be because the compound nucleus 288Fl only has 174 neutrons instead of the supposed magic 184, and this would have significant impact on the reaction cross section (yield) and half-lives of nuclei produced. It was then 30 more years before flerovium was first made. Later work suggests the islands of stability around hassium and flerovium occur because these nuclei are respectively deformed and oblate, which make them resistant to spontaneous fission, and that the true island of stability for spherical nuclei occurs at around unbibium-306 (122 protons, 184 neutrons). In the 1970s and 1980s, theoretical studies debated whether element 114 would be a more volatile metal like lead, or an inert gas.
=== Precautions === Pioglitazone/metformin should not be used in people with type 1 diabetes or for the treatment of diabetic ketoacidosis and should be used with caution in people with edema. Serum ALT levels should be evaluated prior to the initiation of therapy with combination of pioglitazone and metformin and periodically thereafter per the clinical judgment of the health care professional.
Sources: en.wikipedia.org
As an antagonist at ionotropic AMPA, NMDA and Kainate glutamate receptors in the concentration range of 0.1-2.5 mM. As a noncompetitive antagonist at the glycine site of the NMDA receptor. As an antagonist of the α7 nicotinic acetylcholine receptor. However, recently (2011) direct recording of α7 nicotinic acetylcholine receptor currents in adult (noncultured) hippocampal interneurons by the Cooper laboratory validated a 2009 study that failed to find any blocking effect of kynurenic acid across a wide range of concentrations, thus suggesting that in noncultured, intact preparations from adult animals there is no effect of kynurenic acid on α7 nicotinic acetylcholine receptor currents. As a ligand for the orphan G protein-coupled receptor GPR35. As an agonist for the G protein-coupled receptor HCAR3.
== Digico Prince == In 1981, Digico started manufacturing a CP/M based microcomputer with business software options, named Digico Prince, with a claimed unique seven year maintenance guarantee. A more sophisticated multi-user Digico Prince II system was also available. The Digico 3800 user terminal had three Zilog Z80A processors, 64 kilo-bytes of memory and optionally two floppy disk drives. Up to three Digico 3800s could be connected to a 3810, 3820 or 3830 master workstation with a shared 5 MB Winchester disk drive. Up to 32 of these clusters could further be connected locally or remotely to a Digico 7800 server based on a Digico Micro 16E, providing more shared disc capacity and remote access to IBM, ICL and Honeywell mainframe computers.
Turtles have two or more accessory urinary bladders, located lateral to the neck of the urinary bladder and dorsal to the pubis, occupying a significant portion of their body cavity. Their bladder is also usually bilobed with a left and right section. The right section is located under the liver, which prevents large stones from remaining in that side while the left section is more likely to have calculi.
2 CH3OH + O2 → 2 CH2O + 2 H2O The silver-based catalyst usually operates at a higher temperature, about 650 °C. Two chemical reactions on it simultaneously produce formaldehyde: that shown above and the dehydrogenation reaction
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.
Reported activity is highest at MC4R, with lower potency at MC1R and MC3R. The MC4R interaction is generally treated as the most relevant to its central effects. Selectivity is not absolute, and activity across the family is dose-dependent.