If you have been reading about melanocortin receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-06-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
==== Histone O-GlcNAcylation ==== Histone proteins, the primary protein component of chromatin, have been reported to be modified by O-GlcNAc, though other studies have not been able to detect histone O-GlcNAc. The presence of O-GlcNAc on histones has been suggested to affect gene transcription as well as other histone marks such as acetylation and monoubiquitination. TET2 has been reported to interact with the TPR domain of OGT and facilitate recruitment of OGT to histones. Phosphorylation of OGT T444 via AMPK has been found to inhibit OGT-chromatin association and downregulate H2B S112 O-GlcNAc.
The newest formulation to come out was in 2014 when zohydro, an increased dosage formula of hydrocodone, was released; this is so far the strongest hydrocodone formulation created for pain management, on par with a moderate dose of oxycodone .
Menus included 72 items; for the first time about 15% was frozen. Shrimp cocktail and butter cookies were consistent favorites; Lobster Newberg, fresh bread, processed meat products, and ice cream were among other choices. The food was similar to that used for Apollo, but were sealed in cans for preservation. The crew found it to be better than that of Apollo but still unsatisfying, partially due to food tasting different in space than on Earth. The frozen foods were the most popular, and they enjoyed spicy foods due to sinus congestion from weightlessness dulling their senses of taste and smell. Weightlessness also complicated the process of both eating and cleaning up, with crews spending up to 90 minutes a day on housekeeping. At the request of astronauts, NASA included cream sherry for one Skylab mission and packaged some for testing on a reduced-gravity aircraft. In microgravity, smells quickly permeate the environment and the agency found that the sherry triggered the gag reflex. Concern over public reaction to taking alcohol into space led NASA to abandon its plans. The astronauts instead drank the purchased supply while consuming their pre-mission special diet. The astronauts of the Apollo–Soyuz Test Project (1975) received samples of Soviet space food when the combined crew dined together. Among the foods provided by Soyuz 19 were canned beef tongue, packaged Riga bread, tubes of borscht (beet soup), and caviar. The borscht was labeled "vodka".
The golden age of taxidermy was during the Victorian era, when mounted animals became a popular part of interior design and decor. English ornithologist John Hancock is considered to be the father of modern taxidermy. An avid collector of birds, which he had shot personally, he began modeling them with clay and casting in plaster. For the Great Exhibition of 1851 in London, he mounted a series of stuffed birds as an exhibit. They generated much interest among the public and scientists alike who considered them superior to earlier models, and they were regarded as the first lifelike and artistic specimens on display. A judge remarked that Hancock's exhibit "... will go far towards raising the art of taxidermy to a level with other arts which have hitherto held higher pretensions". Hancock's display sparked great national interest in taxidermy, and amateur and professional collections for public view proliferated rapidly. Displays of birds were particularly common in middle-class Victorian homes – even Queen Victoria amassed an impressive bird collection. Taxidermy was also increasingly used by the bereaved owners of dead pets to 'resurrect' them.
l-DOPA, also known as l-3,4-dihydroxyphenylalanine and used medically as levodopa, is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize l-DOPA, make it via biosynthesis from the amino acid l-tyrosine. l-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), which are collectively known as catecholamines. Furthermore, l-DOPA itself mediates neurotrophic factor release by the brain and central nervous system. In some plant families (of the order Caryophyllales), l-DOPA is the central precursor of a biosynthetic pathway that produces a class of pigments called betalains. l-DOPA can be manufactured and in its pure form is sold as a drug with the INNTooltip International Nonproprietary Name levodopa. As a drug, it is used in the treatment of Parkinson's disease and dopamine-responsive dystonia, as well as restless leg syndrome. l-DOPA has a counterpart with opposite chirality, d-DOPA. As is true for many molecules, the human body produces only one of these isomers (the l-DOPA form). The enantiomeric purity of l-DOPA may be analyzed by determination of the optical rotation or by chiral thin-layer chromatography.
Sources: en.wikipedia.org
=== Roman era === During the Roman era there was a settlement named Abona at the present Sea Mills; this was important enough to feature in the 3rd-century Antonine Itinerary which documents towns and distances in the Roman empire, and was connected to Bath by a road. Archaeological excavations at Abona have found a street pattern, shops, cemeteries and wharves, indicating that the town served as a port. Another settlement at what is now Inns Court, Filwood, had possibly developed from earlier Iron Age farmsteads. There were also isolated villas and small settlements throughout the area, notably Kings Weston Roman Villa and another at Brislington.
=== Agriculture's role in the economy === The significance and structure of a country's agricultural sector will affect digital agriculture adoption. For example, a grain-based economy needs difference technologies than a major vegetable producer. Automated, digitally-enabled harvesting systems might make sense for grains, pulses and cotton, but only a few specialty crops generate enough value to justify large investments in mechanized or automated harvesting. Farm size also affects technology choices, as economies of scale make large investments possible (e.g., adoption of precision agriculture is more likely on larger farms). On the other hand, digital agriculture solutions focused on ICTs and e-commerce would benefit an economy dominated by smallholders. In China, where the average farm size is less than 1 ha, Alibaba's customer-to-customer e-commerce platform called Rural Taobao has helped melon growers in Bachu County market their produce all over the country. Other structural factors, such as percent of the population employed in agriculture, farm density, farm mechanization rates, and other factors also impact how different regions adopt digital agriculture.
Noriega and Torrijos later used their knowledge of the U.S. wiretapping operations to tilt the Panama Canal negotiations in their favor. Noriega's drug-related activities came to the U.S. government's attention once again during the ratification process for the Panama Canal treaties, but were once again downplayed by the U.S. intelligence services to get the treaty ratified by the U.S. Senate.
All were impressed by the new DNA model, especially Brenner who subsequently worked with Crick at Cambridge in the Cavendish Laboratory and the new Laboratory of Molecular Biology. According to the late Dr. Beryl Oughton, later Rimmer, they all travelled together in two cars once Dorothy Hodgkin announced to them that they were off to Cambridge to see the model of the structure of DNA. Orgel also later worked with Crick at the Salk Institute for Biological Studies. Crick was often described as very talkative, with Watson – in The Double Helix – implying lack of modesty. His personality combined with his scientific accomplishments produced many opportunities for Crick to stimulate reactions from others, both inside and outside the scientific world, which was the centre of his intellectual and professional life. Crick spoke rapidly, and rather loudly, and had an infectious and reverberating laugh, and a lively sense of humour. One colleague from the Salk Institute described him as "a brainstorming intellectual powerhouse with a mischievous smile. ... Francis was never mean-spirited, just incisive. He detected microscopic flaws in logic. In a room full of smart scientists, Francis continually re-earned his position as the heavyweight champ."
Sources: en.wikipedia.org
Spironolactone is an antimineralocorticoid (antagonist of the mineralocorticoid receptor) and potassium-sparing diuretic, which is mainly used to treat high blood pressure, edema, high aldosterone levels, and low potassium levels caused by other diuretics, among other uses. Spironolactone is an antiandrogen as a secondary and originally unintended action. It works as an antiandrogen mainly by acting as an androgen receptor antagonist. The medication is also a weak steroidogenesis inhibitor, and inhibits the enzymatic synthesis of androgens. However, this action is of low potency, and spironolactone has mixed and inconsistent effects on hormone levels. In any case, testosterone levels are usually unchanged by spironolactone. Studies in transgender women have found testosterone levels to be unaltered with spironolactone or to be decreased. Spironolactone is described as a relatively weak antiandrogen. It is widely used in the treatment of acne, excessive hair growth, and hyperandrogenism in women, who have much lower testosterone levels than men. Because of its antimineralocorticoid activity, spironolactone has antimineralocorticoid side effects and can cause high potassium levels. Hospitalization and/or death can potentially result from high potassium levels due to spironolactone, but the risk of high potassium levels in people taking spironolactone appears to be minimal in those without risk factors for it. As such, monitoring of potassium levels may not be necessary in most cases.
The parish church of St Peter and St Paul stands on Church Road. It was largely destroyed by German bombing on 16 April 1941 and rebuilt in the 1950s incorporating the medieval tower and reusing much of the flint and fragments of the original stone building. The most noteworthy historic building is Bromley College, London Road. The central public open spaces are; Queen's Gardens, Martin's Hill, Church House Gardens, Library Gardens and College Green.
=== Pituitary gland (hypophysis) === The pituitary gland (or hypophysis) is an endocrine gland about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold (diaphragma sellae). The pituitary is functionally connected to the hypothalamus by the median eminence via a small tube called the infundibular stem or pituitary stalk. The anterior pituitary (adenohypophysis) is connected to the hypothalamus via the hypothalamo–hypophyseal portal vessels, which allows for quicker and more efficient communication between the hypothalamus and the pituitary.
Seven Labour MPs, including former shadow chancellor John McDonnell and former shadow minister Rebecca Long-Bailey, have the Labour whip suspended for six months after voting against the government and in favour of an SNP amendment to scrap the two-child benefit cap. McDonnell said, "I'm following Keir Starmer's example as he said put country before party". Dressage rider Charlotte Dujardin withdraws from the 2024 Summer Olympics after a video emerged online of her excessively whipping a horse. Dujardin describes her actions as an "error of judgement." 24 July July 2024 Welsh Labour leadership election: Eluned Morgan is elected unopposed as the new leader of Welsh Labour after nominations close at midday. A policeman is filmed kicking and stamping on the head of a man at Manchester Airport. The officer concerned is subsequently suspended from the force pending an investigation. 26 July France railway arson attack: A series of attacks are staged on the infrastructure of the TGV rail network, resulting in damage and cancellations. Eurostar trains linking the UK and France are also affected by this. The UK confirms it will retract a previous objection to ICC arrest warrants against Israeli Prime Minister Benjamin Netanyahu and Defense Minister Yoav Gallant. The Independent Office for Police Conduct confirms a police officer will face a criminal investigation over an incident where a man was kicked and stamped on at Manchester Airport.
== Drug interactions == Tylosin may increase digitalis blood levels, thus its toxicity, and may be antagonistic to chloramphenicol or lincosamides. Colorimetric assays of serum ALT and AST may be falsely elevated by macrolide antibiotics.
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.