The short version of Cyclic heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-08. Anything still debated is marked as such rather than presented as settled.
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.
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.
Compared with the related compound melanotan II, PT-141 shows markedly weaker activation of receptors tied to pigmentation. This difference stems from subtle structural variations that alter affinity distribution across receptor subtypes. Investigators propose that such selectivity produces a different side effect profile in specific applications. However, downstream consequences of prolonged receptor activation remain uncertain in the literature. Published studies do not fully agree on the duration of signaling pathway activity and the mechanisms of desensitization.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Cyclic heptapeptide | Synthetic melanocortin analogue |
| Molecular formula | C50H68N14O10 | Corresponds to a mass near 1025 daltons |
| Appearance | White to off-white powder | Lyophilised solid before reconstitution |
| Solubility | Soluble in water and polar solvents | Poor solubility in nonpolar media |
| Common synonyms | Bremelanotide, PT-141 | Code name and international name used interchangeably |
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.
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 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.
== Medical uses == Skin, vaginal, mouth, and esophageal Candida infections usually respond well to treatment with nystatin. Infections of nails or hyperkeratinized skin do not respond well. When given parenterally (that is, other routes besides oral/topical/vaginal), its activity is reduced due to presence of plasma. Oral nystatin is often used as a preventive treatment in people who are at risk for fungal infections, such as AIDS patients with a low CD4+ count and people receiving chemotherapy. It has been investigated for use in patients after liver transplantation, but fluconazole was found to be much more effective for preventing colonization, invasive infection, and death. It is effective in treating oral candidiasis in elderly people who wear dentures. It is also used in very low birth-weight (less than 1500 g or 3 lb 5oz o) infants to prevent invasive fungal infections, although fluconazole is the preferred treatment. It has been found to reduce the rate of invasive fungal infections and also reduce deaths when used in these babies. Liposomal nystatin is not commercially available, but investigational use has shown greater in vitro activity than colloidal formulations of amphotericin B, and demonstrated effectiveness against some amphotericin B-resistant forms of fungi. It offers an intriguing possibility for difficult-to-treat systemic infections, such as invasive aspergillosis, or infections that demonstrate resistance to amphotericin B. Cryptococcus is also sensitive to nystatin.
=== Hernia repair === Multi-layered OFM devices, reinforced with synthetic polymer were first described in 2008 and in the scientific literature in 2010. These devices, termed ‘reinforced biologics’ have been designed for applications in the surgical repair of hernia as an alternative to synthetic surgical mesh (a mesh prosthesis). OFM reinforced biologics are distributed in the US by Tela Bio Inc. Clinical studies have shown that OFM reinforced biologics have lower hernia recurrence rates versus synthetic hernia meshes. or biologics such as acellular dermis.
Companies specialising in the handling, ripening, preparation, packaging, conservation, distribution, importing and exporting of all types of fresh and frozen products. The purchasing centres of the large food distribution chains (supermarkets, greengrocer chains, etc.) that source their fresh produce in Mercabarna. Companies that specialise in supplying the catering industry. Logistics companies specialising in food and other support services: large cold-chain logistic operators, transport companies, quality control laboratories, packaging companies, auto repair shops, banks, restaurants, hotels, petrol stations, day-care centres, chemists, IT companies, courier services, consulting firms, hardware stores, etc.
In the early 19th century, the British sought to reform the settlers, threatening to suspend the Public Meeting unless it observed the government's instructions to eliminate slavery outright. After a generation of wrangling, slavery was abolished in the British Empire in 1833. As a result of their enslaved Africans' abilities in the work of mahogany extraction, owners in British Honduras were compensated £53.34 per enslaved African on average (equivalent to £5,100 in 2025), the highest amount paid in any British territory. The end of slavery did little to change the formerly enslaved Africans' working conditions if they stayed at their trade. A series of institutions restricted the ability of emancipated African individuals to buy land, in a debt-peonage system. Former "extra special" mahogany or logwood cutters undergirded the early ascription of the capacities (and consequently the limitations) of people of African descent in the colony. Because a small elite controlled the settlement's land and commerce, formerly enslaved Africans had little choice but to continue to work in timber cutting. In 1836, after the emancipation of Central America from Spanish rule, the British claimed the right to administer the region. In 1862, the United Kingdom formally declared it a British Crown Colony, subordinate to Jamaica, and named it British Honduras. Since 1854, the richest inhabitants elected an assembly of notables by censal vote, which was replaced by a legislative council appointed by the British government. As a colony, Belize began to attract British investors.
=== Alternative medicine === A 2018 Cochrane review on acupuncture and related interventions for the treatment of carpal tunnel syndrome concluded that "Acupuncture and laser acupuncture may have little or no effect in the short term on symptoms of carpal tunnel syndrome (CTS) in comparison with placebo or sham acupuncture." It was also noted that all studies had an unclear or high overall risk of bias and that all evidence was of low or very low quality.
Sources: en.wikipedia.org
The kinetic energy distribution in the direction of ion flight can be corrected by using a reflectron. The reflectron uses a constant electrostatic field to reflect the ion beam toward the detector. The more energetic ions penetrate deeper into the reflectron, and take a slightly longer path to the detector. Less energetic ions of the same mass-to-charge ratio penetrate a shorter distance into the reflectron and, correspondingly, take a shorter path to the detector. The flat surface of the ion detector (typically a microchannel plate, MCP) is placed at the plane where ions of same m/z but with different energies arrive at the same time counted with respect to the onset of the extraction pulse in the ion source. A point of simultaneous arrival of ions of the same mass-to-charge ratio but with different energies is often referred as time-of-flight focus. An additional advantage to the re-TOF arrangement is that twice the flight path is achieved in a given length of the TOF instrument.
This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, inverse of the thermodynamic power cycle. In the power cycle, heat is supplied from a high-temperature source to the engine, part of the heat being used to produce work and the rest being rejected to a low-temperature sink. This satisfies the second law of thermodynamics. A refrigeration cycle describes the changes that take place in the refrigerant as it alternately absorbs and rejects heat as it circulates through a refrigerator. It is also applied to heating, ventilation, and air conditioning HVACR work, when describing the "process" of refrigerant flow through an HVACR unit, whether it is a packaged or split system. Heat naturally flows from hot to cold. Work is applied to cool a living space or storage volume by pumping heat from a lower temperature heat source into a higher temperature heat sink. Insulation is used to reduce the work and energy needed to achieve and maintain a lower temperature in the cooled space. The operating principle of the refrigeration cycle was described mathematically by Sadi Carnot in 1824 as a heat engine. The most common types of refrigeration systems use the reverse-Rankine vapor-compression refrigeration cycle, although absorption heat pumps are used in a minority of applications. Cyclic refrigeration can be classified as:
=== Shortages === In February 2023, news organizations began reporting on shortages of Adderall in the United States that had lasted for over five months. The US Food and Drug Administration (FDA) first reported the shortage in October 2022. In May 2023, seven months into the shortage, the FDA commissioner stated that "a number of generic drugs are in shortage at any given time because there's not enough profit". He points out that Adderall is a special case because it is a controlled substance and the amount available for prescription is controlled by the Drug Enforcement Administration. He also faults a "tremendous increase in prescribing" due to virtual prescribing and general overprescribing and overdiagnosing, adding that "if only the people that needed these drugs got them, there probably wouldn't be a [stimulant medication] shortage". The shortage has continued into 2025. It has led to the creation and expansion of businesses that outsource the search for Adderall. One company charges $50 per U.S. customer to hire workers in the Philippines or another country to make phone calls to all the pharmacies located near the customer and check whether they have any Adderall.
As of 1 Jan 2008, all officers from Quartermaster, Transportation and Ordnance branches who have attended the Captain's Career Course, with the exception of EOD officers (89E), are transitioned to the Logistics branch. Officer
=== N05CD Benzodiazepine derivatives === N05CD01 Flurazepam N05CD02 Nitrazepam N05CD03 Flunitrazepam N05CD04 Estazolam N05CD05 Triazolam N05CD06 Lormetazepam N05CD07 Temazepam N05CD08 Midazolam N05CD09 Brotizolam N05CD10 Quazepam N05CD11 Loprazolam N05CD12 Doxefazepam N05CD13 Cinolazepam N05CD14 Remimazolam N05CD15 Nimetazepam
Sources: en.wikipedia.org
Many common language terms used for fruit and seeds differ from botanical classifications. For example, in botany, a fruit is a ripened ovary or carpel that contains seeds, e.g., an orange, pomegranate, tomato or a pumpkin. A nut is a type of fruit (and not a seed), and a seed is a ripened ovule. In culinary language, a fruit is the sweet- or not sweet- (even sour-) tasting produce of a specific plant (e.g., a peach, pear or lemon); nuts are hard, oily, non-sweet plant produce in shells (e.g. hazelnut, acorn). Vegetables, so-called, typically are savory or non-sweet produce (e.g. zucchini, lettuce, broccoli, and tomato). But some may be sweet-tasting (sweet potato).
These kilns can be the fastest to dry and most efficient with energy usage. In a vacuum, water boils at a lower temperature. In addition to increased speed, a vacuum kiln can also produce an improved quality in the wood. Low ambient pressure does lower the boiling point of water but the amount of energy required to convert the liquid to vapor is the same. Savings come from not being required to heat a huge building and not being required to vent the heat while lowering humidity. Since all free water can be removed at below 115 °F, quality is improved. While conventional drying uses warm, dry air to skim water off the surface, vacuum kilns can boil water from within the wood. This enables a good vacuum kiln to dry very thick wood very quickly. It is possible to dry 12/4 Red Oak fresh off the saw to 7% in 11 days. Since wood is dried with a vapor gradient - vapor pressure to ambient pressure - humidity can be kept very high. Because of this, a good vacuum kiln can dry 4.5" thick White Oak fresh off the saw to 8% in less than a month, a feat that was previously thought to be impossible.
Specialized UV gas-discharge lamps containing different gases produce UV radiation at particular spectral lines for scientific purposes. Argon and deuterium arc lamps are often used as stable sources, either windowless or with various windows such as magnesium fluoride. These are often the emitting sources in UV spectroscopy equipment for chemical analysis. Other UV sources with more continuous emission spectra include xenon arc lamps (commonly used as sunlight simulators), deuterium arc lamps, mercury-xenon arc lamps, and metal-halide arc lamps.
Milk ejection reflex/Letdown reflex: in lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be 'let down' into lactiferous ducts, from where it can be excreted via the nipple. Suckling by the infant at the nipple is relayed by spinal nerves to the hypothalamus. The stimulation causes neurons that produce oxytocin to fire action potentials in intermittent bursts; these bursts result in oxytocin pulses from the neurosecretory nerve terminals of the pituitary gland. Uterine contraction: important for cervical dilation before birth, oxytocin causes contractions during the second and third stages of labor. Oxytocin release during breastfeeding causes mild but often painful contractions during the first few weeks of lactation. This also assists the uterus in clotting the placental attachment point postpartum. However, in knockout mice lacking the oxytocin receptor, reproductive behavior and birth are normal. In male rats, oxytocin may induce erections. A burst of oxytocin is released during ejaculation in several species, including human males; its suggested function is to stimulate contractions of the reproductive tract, aiding sperm release. Human sexual response: Oxytocin levels in plasma rise during sexual stimulation and orgasm. At least two uncontrolled studies have found increases in plasma oxytocin at orgasm in both men and women. Plasma oxytocin levels are increased around the time of self-stimulated orgasm and are still higher than baseline when measured five minutes after self arousal.
In the Philippines, circumcision is known as "tuli" and is generally viewed as a rite of passage. An overwhelming majority of Filipino men are circumcised. Often this occurs in April and May, when Filipino boys are taken by their parents. The practice dates back to the arrival of Islam in 1450. Pressure to be circumcised is even in the language: one Tagalog profanity for "uncircumcised" is supot, meaning "coward". A circumcised eight- or ten-year-old is no longer considered a boy and is given more adult roles in the family and society.
Sources: en.wikipedia.org
PT-141 is a laboratory code for bremelanotide, a synthetic peptide that activates melanocortin receptors. It has been developed both as an injectable pharmaceutical product and as a research chemical. The two contexts differ sharply in how identity, purity, and dosing are controlled.
It is neither a steroid nor a naturally occurring human hormone. Bremelanotide is a manufactured peptide that mimics part of the melanocortin signalling system by binding receptor proteins. Its effects come from receptor activation, not from replacing a circulating hormone.
The internal lactam bridge locks the peptide into a defined shape, which raises receptor affinity and slows enzymatic breakdown. Linear versions of the same sequence are less stable and bind more weakly. Ring geometry is therefore central to how the molecule behaves in the body.
It primarily activates specific subtypes in the melanocortin receptor family. These receptors are G protein-coupled and mediate signaling mainly within the central nervous system.