The short version of Heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-30. Anything still debated is marked as such rather than presented as settled.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
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。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
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.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
The presence of ptaquiloside has been detected in a variety of ferns, including the species in the genera Pteridium (bracken), Pteris, Microlepia, and Hypolepis. Pteridium aquilinum (commonly known as bracken fern) is the most common ptaquiloside-containing fern with a wide geographical and ecological distribution. It is present in all continents from subtropic to subarctic areas. Bracken fern is a very adaptable plant and is capable of forming dense, rapidly expanding populations in course of the first phases of the ecological succession in forest cleanings and other disturbed rural areas. Its aggressive growth, characterized by an extensive rhizome system and rapidly growing fronds, sometimes enables it to be a dominant species in certain plant communities. The ptaquiloside content of bracken varies widely across species and changes with the part of the plant, the plant growing site and the collecting season. According to previous studies, the concentrations of ptaquiloside in bracken varied between 0 and 1% of the dry weight of the plant. Generally, ptaquiloside is found to occur in the highest concentrations in the young developing parts of bracken, such as the croziers and unfolding parts during the spring and early summer, while the concentrations of ptaquiloside in the rhizomes are rather low. However, studies on the concentrations of ptaquiloside in Danish bracken by Rasmussen et al. showed that the concentrations of ptaquiloside in the rhizomes were significantly higher than the previously reported values.
Proteinogenic amino acids Cysteine (Cys, C) Methionine (Met or M), an essential amino acid in humans Metabolic products: Cystine, a cysteine dimer, and an oxidation product of cysteine Homocysteine (Hcy) Homocystine, a homocysteine dimer, and an oxidation product of homocysteine Cystathionine, produced by the transsulfuration pathway S-Adenosyl methionine (SAM, SAMe, SAM-e, AdoMet), a common cofactor in methyltransferases S-Adenosyl homocysteine (SAH), a side product of biomethylation by methyltransferases
== Types of standard solutions == Standard solutions can be categorized by the type of analyte used to prepare them. These analytical standards can either be a primary standard or a secondary standard.
=== Synthesis of lithium-titanate breeder powder === Li2TiO3 powder is most commonly prepared by the mixing of lithium carbonate, Ti-nitrate solution, and citric acid followed by calcination, compaction, and sintering. The nanocrystalline material created is used as a breeder powder due to its high purity and activity.
In the subsurface environment, 39Ar is also produced through neutron capture by 39K or 42Ca, with proton or alpha emission respectively; 37Ar was created in subsurface nuclear explosions similarly from 40Ca. The content of 39Ar in natural argon is measured to be of (8.6±0.4)×10−16 g/g, or (0.964±0.024) Bq/kg weight. The content of 42Ar (half-life 33 years) in the Earth's atmosphere, though it had previously been reported as a cosmogenic isotope, is lower than 6×10−21 of the element. Many endeavors require argon depleted in the cosmogenic isotopes, known as depleted argon and this may be obtained from underground sources that have been isolated from the atmosphere long enough for these isotopes to decay. 36Ar, in the form of argon hydride, was detected in the Crab Nebula supernova remnant during 2013. This was the first time a noble molecule was detected in outer space.
Sources: en.wikipedia.org
Rennet () is a complex set of enzymes produced in the stomachs of ruminant mammals. Its key component is chymosin, a protease enzyme that curdles the casein proteins in milk. Rennet also contains other enzymes such as pepsin and a lipase. Rennet has traditionally been used to separate milk into solid curds and liquid whey, used in the production of cheeses. Rennet from calves has become less common for this use, to the point that less than 5% of cheese in the United States is made using animal rennet today. Most cheese is now made using chymosin derived from bacterial sources.
=== Blood, lymph and nerve supply === The tissues of the vulva are highly vascularised and blood supply is provided by the three pudendal arteries. Venous return is via the external and internal pudendal veins. The organs and tissues of the vulva are drained by a chain of superficial inguinal lymph nodes located along the blood vessels. The ilioinguinal nerve originates from the first lumbar nerve and gives branches that include the anterior labial nerves, which supply the skin of the mons pubis and the labia majora. The perineal nerve is one of the terminal branches of the pudendal nerve and this branches into the posterior labial nerves to supply the labia. The pudendal nerve branches include the dorsal nerve, which gives sensation to the clitoris. The clitoral glans is seen to be populated by a large number of small nerves, a number that decreases as the tissue changes towards the urethra. The density of nerves at the glans indicates that it is the center of heightened sensation. Cavernous nerves from the uterovaginal plexus supply the erectile tissue of the clitoris. These are joined underneath the pubic arch by the dorsal nerve of the clitoris. The pudendal nerve enters the pelvis through the lesser sciatic foramen and continues medial to the internal pudendal artery. The point where the nerve circles the ischial spine is the location where a pudendal block of local anesthetic can be administered to inhibit sensation to the vulva. A number of smaller nerves split off from the pudendal nerve.
== United States usage == The Congress of the United States customarily adjourns a session sine die on the morning of January 3, immediately before the next session holds its constitutionally mandated first meeting. It can also adjourn sine die at other times through a concurrent resolution that allows the Speaker of the House and Senate Majority Leader to resume the session. State legislatures follow suit and mark adjournment sine die with a ceremony, such as the Connecticut General Assembly wherein, on the final day of the legislative session, the House and Senate meet in a joint convention, and the Secretary of the State recites "Oyez, Oyez, Oyez", pounds the gavel, and declares the legislature adjourned sine die. In the Florida Legislature, the sergeants-at-arms of the Florida Senate and the Florida House of Representatives step outside their chambers each holding a handkerchief. When they meet in between the chambers, they both drop the handkerchiefs, signifying the end of the legislative session.
The classification presented here, for recent cephalopods, follows largely from Current Classification of Recent Cephalopoda (May 2001), for fossil cephalopods takes from Arkell et al. 1957, Teichert and Moore 1964, Teichert 1988, and others. The three subclasses are traditional, corresponding to the three orders of cephalopods recognized by Bather. Class Cephalopoda († indicates extinct groups)
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。