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 2025-12-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
=== Institution === Filomena Teixeira launched in 2007 an association for missing children, the Association of Family Members of Portuguese Missing Children. At the inauguration was Laurinda Meira, the mother of Rui Pereira, who disappeared in Famalicão, also in 1998. Two thousand children were also present.
Cast iron was first produced in China during 5th century BC, but did not become widely produced in Europe until the medieval period. The earliest cast iron artifacts were discovered by archaeologists in what is now modern Luhe County, Jiangsu in China. Cast iron was used in ancient China for warfare, agriculture, and architecture. During the medieval period, means were found in Europe of producing wrought iron from cast iron (in this context known as pig iron) using finery forges. For all these processes, charcoal was required as fuel.
In music, birdsong has influenced composers and musicians in several ways: they can be inspired by birdsong; they can intentionally imitate bird song in a composition, as Vivaldi, Messiaen, and Beethoven did, along with many later composers; they can incorporate recordings of birds into their works, as Ottorino Respighi first did; or like Beatrice Harrison and David Rothenberg, they can duet with birds. A 2023 archaeological excavation of a 10,000-year-old site in Israel yielded hollow wing bones of coots and ducks with perforations made on the side that are thought to have allowed them to be used as flutes or whistles possibly used by Natufian people to lure birds of prey.
It is divided between its east and west coasts by the Titiwangsa Mountains, rising to a peak elevation of 2,183 metres (7,162 ft) at Mount Korbu, part of a series of mountain ranges running down the centre of the peninsula. These mountains are heavily forested, and mainly composed of granite and other igneous rocks. Much of it has been eroded, creating a karst landscape. The range is the origin of some of Peninsular Malaysia's river systems. The coastal plains surrounding the peninsula reach a maximum width of 50 kilometres (31 mi), and the peninsula's coastline is nearly 1,931 km (1,200 mi) long, although harbours are only available on the western side.
Hemoglobin D (HbD) is a variant of hemoglobin, a protein complex that makes up red blood cells. Based on the locations of the original identification, it has been known by several names such as hemoglobin D-Los Angeles, hemoglobin D-Punjab, D-North Carolina, D-Portugal, D-Oak Ridge, and D-Chicago. Hemoglobin D-Los Angeles was the first type identified by Harvey Itano in 1951, and was subsequently discovered that hemoglobin D-Punjab is the most abundant type that is common in the Sikhs of Punjab (of both Pakistan and India) and of Gujarat. Unlike normal adult human hemoglobin (HbA) which has glutamic acid at its 121 amino acid position, it has glutamine instead. The single amino acid substitution can cause various blood diseases, from fatal genetic anemia to mild hemolytic anemia, an abnormal destruction of red blood cells. Depending on the type of genetic inheritance, it can produce four different conditions: heterozygous (inherited in only one of the chromosome 11) HbD trait, HbD-thalassemia, HbS-D (sickle cell) disease, and, very rarely, homozygous (inherited in both chromosome 11) HbD disease. It is the fourth hemoglobin type discovered after HbA, HbC and HbS; the third hemoglobin variant identified after HbC and HbS; and the fourth most common hemoglobin variant after HbC, HbS, and HbO.
Sources: en.wikipedia.org
chemokinesis A non-directional, random change in the movement of a molecule, cell, or organism in response to a chemical stimulus, e.g. a change in speed resulting from exposure to a particular chemical compound.
Insertions add one or more extra nucleotides into the DNA. They are usually caused by transposable elements, or errors during replication of repeating elements. Insertions in the coding region of a gene may alter splicing of the mRNA (splice site mutation), or cause a shift in the reading frame (frameshift), both of which can significantly alter the gene product. Insertions can be reversed by excision of the transposable element. Deletions remove one or more nucleotides from the DNA. Like insertions, these mutations can alter the reading frame of the gene. In general, they are irreversible: Though exactly the same sequence might, in theory, be restored by an insertion, transposable elements able to revert a very short deletion (say 1–2 bases) in any location either are highly unlikely to exist or do not exist at all. Substitution mutations, often caused by chemicals or malfunction of DNA replication, exchange a single nucleotide for another. These changes are classified as transitions or transversions. Most common is the transition that exchanges a purine for a purine (A ↔ G) or a pyrimidine for a pyrimidine, (C ↔ T). A transition can be caused by nitrous acid, base mispairing, or mutagenic base analogues such as BrdU. Less common is a transversion, which exchanges a purine for a pyrimidine or a pyrimidine for a purine (C/T ↔ A/G). An example of a transversion is the conversion of adenine (A) into a cytosine (C). Point mutations are modifications of single base pairs of DNA or other small base pairs within a gene.
She also decided against sending him a letter threatening him with the sack, which had been drafted. Instead she asked Mayhew to write to Heseltine complaining of what he thought were "material inaccuracies" in his letter to Horne, and asking Heseltine to write to Horne again, correcting them. Mayhew's letter of rebuke to Heseltine – marked "Confidential" – reached Heseltine at lunchtime on Monday 6 January and was immediately leaked to the press by Colette Bowe, an information officer at the Department of Trade and Industry, at Brittan's request (some years later he admitted that he acted on the "express" instructions of Charles Powell and Bernard Ingham, Thatcher's two senior advisers). Heseltine was able to produce extra documents which Mayhew accepted as backing up his letter to Horne, but not before The Sun had called Heseltine "You Liar!" on its front page (the newspaper was later required to make a donation to charity in lieu of libel damages).
Citrus greening disease (Chinese: 黃龍病; pinyin: huánglóngbìng abbr. HLB) is a disease of citrus trees caused by bacteria of the genus Liberibacter. These microbes are transmitted by two species of bug: the Asian citrus psyllid Diaphorina citri and the African citrus psyllid Trioza erytreae. It has no known cure. It is graft-transmissible. There are three different types of the disease: a heat-tolerant Asian form, and the heat-sensitive African and American forms. It was first described and reported in southern China in 1919. The African variation was first reported in 1937 in South Africa, where it is still widespread. It reached Florida in 2005, and within three years had spread to the majority of citrus farms. The rapid increase in this disease has threatened the citrus industry in the entire US. As of 2009, 33 countries had reported the infection in their citrus crop.
Sources: en.wikipedia.org
PFOA is also formed as an unintended byproduct in the production of fluorotelomers and is present in finished goods treated with fluorotelomers, including those intended for food contact. Fluorotelomers are applied to food contact papers because they are lipophobic: they prevent oil from soaking into the paper from fatty foods. Also, fluorotelomers can be metabolized into PFOA. In a U.S. Food and Drug Administration (USFDA) study, lipophobic fluorotelomer-based paper coatings (which can be applied to food contact paper in the concentration range of 0.4%) were found to contain 88,000–160,000 parts per billion PFOA before application, while the oil from microwave popcorn bags contained 6–290 parts per billion PFOA after heating. Toxicologists estimate that microwave popcorn could account for about 20% of the PFOA levels measured in an individual consuming 10 bags a year if 1% of the fluorotelomers are metabolized to PFOA. In 2008 as news stories began to raise concerns about PFOA in microwaved popcorn, Dan Turner, DuPont's global public relations chief, said, "I serve microwave popcorn to my three-year-old." Five years later, journalist Peter Laufer wrote to Turner to ask if his child was still eating microwave popcorn. "I am not going to comment on such a personal inquiry", Turner replied. Fluorotelomer coatings are used in fast food wrappers, candy wrappers, and pizza box liners. PAPS, a type of paper fluorotelomer coating, and PFOA precursor, is also used in food contact papers.
You don't need to eat foods from animals to have enough protein in your diet. Plant proteins alone can provide enough of the essential and non-essential amino acids, as long as sources of dietary protein are varied and caloric intake is high enough to meet energy needs. Whole grains, legumes, vegetables, seeds and nuts all contain both essential and non-essential amino acids. You don't need to consciously combine these foods ("complementary proteins") within a given meal. Some institutions use the Protein Digestibility Corrected Amino Acid Score to assess diets without consideration of protein combining and hence find the use of combinations to be a challenge to their methodology.
Heseltine was summoned by BPC to be told to sort out his firm's debts, but instead persuaded them to accept, instead of payment, an equity stake of at least 40% in a new, merged business. The portmanteau name "Haymarket" was suggested by Sir Geoffrey Crowther, chairman of BPC.
Peas also contain high levels of dietary fibre, which consists of cellulose, gums, hemicellulose, pectin, mucilage, lignin, and resistant starches. Dry pea has 17-27% dietary fibre depending on their cultivar, environment, and global growing region. In terms of sugars, pea seeds contain 5-6% sucrose and raffinose. Sucrose ranges from 2.2% to 2.6%, whereas oligosaccharides, such as stachyose have a range of 1.3-3.2%, verbascose 1.2-4.0%, and raffinose 0.2-1.0% depending on cultivar and environment. The fat content of pea seeds ranges from 1.2% to 1.8% depending on the cultivar and about 25% of fatty acids are composed of oleic acid (18:1) and 50% of linoleic acid (18:2). Pea seeds are also a rich source of minerals and vitamins, such as folic acid, riboflavin, pyridoxine, and niacin.
==== Absorption ==== When taken orally, DMT is metabolized by monoamine oxidase (MAO) enzymes in the liver and gut, and is thus not orally bioavailable unless a monoamine oxidase inhibitor (MAOI) is taken (as is naturally found in the ayahuasca brew). As such, DMT by itself is instead taken by parenteral administration. Closely coextending with peak psychedelic effects, the mean time to reach peak concentration (Tmax) has been determined to be 10 to 15 minutes in whole blood after intramuscular injection, and 2 to 3 minutes after intravenous administration. When taken orally mixed in an ayahuasca decoction or in freeze-dried ayahuasca gel caps, DMT Tmax is considerably delayed to 1.8 hours on average, and 1.5 to 2 hours, respectively. DMT peak level concentrations (Cmax) measured in the blood after intramuscular (IM) injection (0.7 mg/kg, n = 11) and in plasma following intravenous administration (0.4 mg/kg, n = 10) of fully psychedelic doses are in the range of around 14 to 154 μg/L and 32 to 204 μg/L, respectively. The corresponding molar concentrations of DMT are therefore in the range of 0.074–0.818 μmol/L in whole blood and 0.170–1.08 μmol in plasma.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.