melanocortin signalling is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-05-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
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 |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Analog of an ACTH fragment |
| Amino acid length | Seven residues | Met-Glu-His-Phe-Pro-Gly-Pro |
| Origin | Moscow, 1980s | Institute of Molecular Genetics |
| Approved regions | Russia and some neighboring states | Not cleared in Western markets |
| Common trade names | Multiple national brands | Sold as a nasal formulation |
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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== Further reading == Barrett SE, Burke RS, Abrams MT, Bason C, Busuek M, Carlini E, et al. (June 2014). "Development of a liver-targeted siRNA delivery platform with a broad therapeutic window utilizing biodegradable polypeptide-based polymer conjugates". Journal of Controlled Release. 183: 124–37. doi:10.1016/j.jconrel.2014.03.028. PMID 24657948. Grazon C, Salas-Ambrosio P, Ibarboure E, Buol A, Garanger E, Grinstaff MW, et al. (January 2020). "Aqueous Ring-Opening Polymerization-Induced Self-Assembly (ROPISA) of N-Carboxyanhydrides" (PDF). Angewandte Chemie. 59 (2): 622–626. doi:10.1002/ange.201912028. PMID 31650664. S2CID 241302007. Jiang, Jinhui; Zhang, Xinyue; Fan, Zhen; Du, Jianzhong (2019-10-15). "Ring-Opening Polymerization of N-Carboxyanhydride-Induced Self-Assembly for Fabricating Biodegradable Polymer Vesicles". ACS Macro Letters. 8 (10): 1216–1221. doi:10.1021/acsmacrolett.9b00606. PMID 35651173. S2CID 203135939. Kramer JR, Onoa B, Bustamante C, Bertozzi CR (October 2015). "Chemically tunable mucin chimeras assembled on living cells". Proceedings of the National Academy of Sciences of the United States of America. 112 (41): 12574–9. Bibcode:2015PNAS..11212574K. doi:10.1073/pnas.1516127112. PMC 4611660. PMID 26420872.
In the absence of catalysts, proteins are slow to hydrolyze. The breakdown of proteins to small peptides and amino acids (proteolysis) is a step in digestion; these breakdown products are then absorbed in the small intestine. The hydrolysis of proteins relies on enzymes called proteases or peptidases. Proteases, which are themselves proteins, come in several types according to the particular peptide bonds that they cleave as well as their tendency to cleave peptide bonds at the terminus of a protein (exopeptidases) vs peptide bonds at the interior of the protein (endopeptidases). Pepsin is an endopeptidase in the stomach. Subsequent to the stomach, the pancreas secretes other proteases to complete the hydrolysis, these include trypsin and chymotrypsin. Protein hydrolysis is employed commercially as a means of producing amino acids from bulk sources of protein, such as blood meal, feathers, keratin. Such materials are treated with hot hydrochloric acid, which effects the hydrolysis of the peptide bonds.
Sources: en.wikipedia.org
Weight gain is also less of a concern with ziprasidone compared to other atypical antipsychotics. In fact, in a trial of long term therapy with ziprasidone, overweight patients (BMI > 27) actually had a mean weight loss overall. According to the manufacturer insert, ziprasidone caused an average weight gain of 2.2 kg (4.8 lbs), which is significantly lower than other atypical antipsychotics, making this medication better for patients that are concerned about their weight. In December 2014, the FDA warned that ziprasidone could cause a potentially fatal skin reaction, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), although this was believed to occur only rarely.
Liu Wencai's administration was notorious for its corruption but effective in achieving Liu Wenhui's goals, collecting 30,000 silver dollars in its first year through the enforcement of various taxes. Liu Wencai also advised his brother to appoint loyalists as county magistrates in areas under their control, ensuring local revenue flowed directly to his forces. In Yibin, Liu Wenhui promoted modern education in both the military and civilian spheres. Also in 1922, Liu Xiang, who had become Sichuan governor, was defeated in a war against Xiong Kewu and Deng Xihou. Liu Wenhui moved his troops to Chongqing to support his nephew, but after Liu Xiang's defeat, he negotiated a withdrawal back to Yibin to avoid the loss of his army. Liu Xiang was subsequently forced to resign his position as governor. From 1922 to 1924, there was constant conflict in Sichuan. According to historian Robert Kapp, the region functioned as a politically isolated ecosystem for much of the early Republican period. Because it was insulated by geography from the rest of China, this allowed a highly fragmented and fluid balance of power to emerge against local warlords. Outside powers, including Wu Peifu of the Zhili Clique and Sun Yat-sen of the Kuomintang, also intervened intermittently in the Sichuan melee to support their chosen side in the larger context of the North-South conflict. Liu Wenhui was generally aligned with Liu Xiang and Liu Chengxun during this period, being promoted to commander of the Ninth Division in February 1923 by Liu Chengxun.
Planar cell polarity (PCP) is a type of cell polarity in which the cells are oriented in a coordinated way across the plane of an epithelial tissue. The orientation is controlled by different cytoplasmic and transmembrane proteins concentrating on two opposite ends of the cells and forming dimers between neighboring cells. Common examples of PCP oriented tissue include animal fur, bird feathers, fish scales, wings of a fruit fly, and stereocilia in the inner ear. PCP also plays a major role in other biological processes, such as wound healing and embryonic development.
Sources: en.wikipedia.org
== Causes == Type 1 diabetes is caused by the destruction of β-cells—the only cells in the body that produce insulin—and the consequent progressive insulin deficiency. Without insulin, the body cannot respond effectively to increases in blood sugar. Due to this, people with untreated diabetes have persistent hyperglycemia. In 70–90% of cases, β-cells are destroyed by one's own immune system, for reasons that are not entirely clear. The best-studied components of this autoimmune response are β-cell-targeted autoantibodies that begin to develop in the months or years before symptoms arise. Typically, antibodies against insulin or the protein GAD65,are the first to develop, followed by antibodies against the proteins IA-2, IA-2β, and/or ZNT8. People with a higher level of these antibodies, especially those who develop them earlier in life, are at higher risk for developing symptomatic type 1 diabetes. The trigger for the development of these antibodies remains unclear. Several explanatory theories have been put forward, and the cause may involve genetic susceptibility, a diabetogenic trigger, and/or exposure to an antigen. The remaining 10–30% of patients with type 1 diabetes have β-cell destruction but no sign of autoimmunity; this is called idiopathic type 1 diabetes (its cause is unknown).
As is standard for peptide representation, the sequence is given from amino terminus to carboxyl terminus; also standard is omission of the designation of chirality, with assumption that all amino acids are in their L- form. The abbreviations are the standard abbreviations for the corresponding proteinogenic amino acids, except for pyroGlu, which refers to pyroglutamic acid, a derivative of glutamic acid. The NH2 at the carboxyl terminus indicates that rather than terminating as a free carboxylate, it terminates as a carboxamide.
=== Sexual dysfunction === Bupropion is less likely than other antidepressants to cause sexual dysfunction. A range of studies indicate that bupropion not only produces fewer sexual side effects than other antidepressants but can actually help to alleviate sexual dysfunction including sexual dysfunction induced by SSRI antidepressants. There have also been small studies suggesting that bupropion or a bupropion/trazodone combination may improve some measures of sexual function in women who have hypoactive sexual desire disorder (HSDD) and are not depressed. According to an expert consensus recommendation from the International Society for the Study of Women's Sexual Health, bupropion can be considered as an off-label treatment for HSDD despite limited safety and efficacy data. Likewise, a 2022 systematic review and meta-analysis of bupropion for sexual desire disorder in women reported that although data were limited, bupropion appeared to be dose-dependently effective for the condition.
Cyclic ADP-ribose, frequently abbreviated as cADPR, is a cyclic adenine nucleotide (like cAMP) with two phosphate groups present on 5' OH of the adenosine (like ADP), further connected to another ribose at the 5' position, which, in turn, closes the cycle by glycosidic bonding to the nitrogen 1 (N1) of the same adenine base (whose position N9 has the glycosidic bond to the other ribose). The N1-glycosidic bond to adenine is what distinguishes cADPR from ADP-ribose (ADPR), the non-cyclic analog. cADPR is produced from nicotinamide adenine dinucleotide (NAD+) by ADP-ribosyl cyclases (EC 3.2.2.5) as part of a second messenger system.
Sources: en.wikipedia.org
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.
It is registered as a medicine in Russia and has been used clinically there for decades. No regulatory agency in Western Europe or North America has approved it for any indication.
Semax corresponds to the four-to-ten fragment of adrenocorticotropic hormone. Because it omits the first three residues, it lacks the adrenal-stimulating action of the full hormone.
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。