A practical reference on Melanocortin receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-23. Anything still debated is marked as such rather than presented as settled.
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。
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
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.
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 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.
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.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
However, by 24 hours after the dose, unchanged EMP could no longer be detected in the circulation. The clearance of EMP from blood plasma is 4.85 ± 0.684 L/h. The volumes of distribution of EMP with intravenous injection were small; under a two-compartment model, the volume of distribution for the central compartment was 0.043 L/kg and for the peripheral compartment was 0.11 L/kg. The plasma protein binding of EMP is high. Estramustine is accumulated in tumor tissue, for instance prostate cancer and glioma tissue, with estramustine levels much higher in these tissues than in plasma (e.g., 6.3- and 15.9-fold, respectively). Conversely, levels of estromustine in tumor versus plasma are similar (1.0- and 0.5-fold, respectively). Estramustine and estromustine appear to accumulate in adipose tissue. The elimination half-life of estromustine with oral EMP was 13.6 hours on average, with a range of 8.8 to 22.7 hours. Conversely, the elimination half-life of estromustine with intravenous injection was 10.3 hours, with a range of 7.36 to 12.3 hours. For comparison, the corresponding elimination half-lives of estrone were 16.5 and 14.7 hours for oral and intravenous administration, respectively. Estramustine and estromustine are mainly excreted in bile and hence in feces. They are not believed to be excreted in urine.
Alternate splicing of the FGA gene produces a minor expanded isoform of Aα termed AαE which replaces Aα in 1–3% of circulating fibrinogen; alternate splicing of FGG produces a minor isoform of γ termed γ' which replaces γ in 8–10% of circulating fibrinogen; FGB is not alternatively spliced. Hence, the final fibrinogen product is composed principally of Aα, Bβ, and γ chains with a small percentage of it containing AαE and/or γ' chains in place of Aα and/or γ chains, respectively. The three genes are transcribed and translated in co-ordination by a mechanism(s) which remains incompletely understood. The coordinated transcription of these three fibrinogen genes is rapidly and greatly increased by systemic conditions such as inflammation and tissue injury. Cytokines produced during these systemic conditions, such as interleukin 6 and interleukin 1β, appear responsible for up-regulating this transcription.
== Applicable fiber types == There are many fiber types that can be excellent candidates for the preparation of preimpregnated fibers. The most common fibers among these candidates are the following fibers.
Sources: en.wikipedia.org
=== Cap snatching in Hantaviridae === Cap snatching has also been investigated in depth for the family Hantaviridae (Bunyavirales). There is evidence that the N protein binds to the 5' cap and protects them from degradation by cellular machinery. The N protein accumulates in cytoplasmic cellular processing bodies (P bodies), sequestering the protected 5' caps as a pool of available primers for the RdRp to begin viral mRNA synthesis. There are four nucleotides on the vRNA that are adjacent the 5' cap for binding. The virus preferentially cleaves mRNA cap at a G residue 14 nucleotides downstream from the cap. Additionally, it usually cleaves caps from nonsense mRNA instead of actively translated mRNA. The N protein can guard host mRNA caps without P-bodies, but they are not used as efficiently by the RdRp. The Hantaviridae RdRp can also engage in a "prime and realign" mechanism: The host oligonucleotide primes mRNA transcription and initiates transcription with a terminal G residue. After several nucleotides are added, the nascent RNA realigns by moving two nucleotides backwards on the repeated terminal sequence (AUCAUCAUC) so that the host G is once again the first nucleotide, creating a 5' end extension.
=== Allergens === Both centipede bites and centipede-containing medicine can cause allergic reactions, yet no natural centipede allergen has been characterized and officially identified until 2021. The novel allergen found in S. mutilans, Sco m 5, was the first natural centipede allergen to be identified and characterized by Lan et al. It was found that Sco m 5 can promote the degranulation of mast cells (i.e. degranulation of mast cells is associated with edema at the respiratory tract). Centipedes used in clinical practice are required to be boiled before administration, and it is whether to keep or discard the head of centipedes in medical uses remained controversial, as the head contains the venom glands.
Alternatively, if the load is moving at a low delta-v relative to the destination, then it can be captured by means of a mass catcher. This could consist of a large, flexible net or inflatable structure that would transfer the momentum of the mass to the larger facility. Once in place, the materials can be moved into place by mechanical means or by means of small thrusters. Materials can be used for manufacturing either in their raw form, or by processing them to extract the constituent elements. Processing techniques include various chemical, thermal, electrolytic, and magnetic methods for separation. In the near term, relatively straightforward methods can be used to extract aluminum, iron, oxygen, and silicon from lunar and asteroidal sources. Less concentrated elements will likely require more advanced processing facilities, which may have to wait until a space manufacturing infrastructure is fully developed. Some of the chemical processes will require a source of hydrogen for the production of water and acid mixtures. Hydrogen gas can also be used to extract oxygen from the lunar regolith, although the process is not very efficient. So a readily available source of useful volatiles is a positive factor in the development of space manufacturing. Alternatively, oxygen can be liberated from the lunar regolith without reusing any imported materials by heating the regolith to 4,530 °F (2,500 °C) in a vacuum. This was tested on Earth with lunar simulant in a vacuum chamber. As much as 20% of the sample was released as free oxygen. Eric Cardiff calls the remainder slag.
Sources: en.wikipedia.org
==== Thyroid hormones ==== There is some evidence for the addition of a thyroid hormone, triiodothyronine, in patients with normal thyroid function. For TRD patients, T3 has been studied in the STAR-D study with having a remission rate of 24.7%. T4 is also being studied for this purpose and found remission rates of 21.5%–64.7% for TRD patients.
== Early life and research == Atul Malhotra is a US citizen born in Edmonton, Alberta, Canada. He attended the University of Alberta in Canada, obtaining a bachelor's degree in Chemistry and a Medical degree in chemistry from the same university. He completed his internal medicine residency at the Mayo Clinic in Rochester, Minnesota. Malhotra does research in the domains of pulmonary medicine, intensive care unit (ICU), obstructive sleep apnea (OSA), and other respiratory biology disciplines. He studies the biology underlying the consequences of sleep apnea as well as its causation. His group uses computational modelling, cell culture techniques, rodent models, epidemiology, and clinical trials in addition to its primary focus on human physiology. Finding new therapeutic targets for sleep apnea is the main goal of his lab to meet a critical public health need. He was global principal investigator for the SURMOUNT-OSA study which led to the FDA approval of tirzepatide for treatment of moderate to severe sleep apnea in people with obesity.
=== Medications === The antifibrotics pirfenidone and nintedanib have been shown to slow the decline in lung function (as measured by forced vital capacity [FVC]) in those with ILD compared to placebo. Pirfenidone was associated with a 45% less decline in FVC at 52 weeks compared to placebo in a trial involving people with idiopathic pulmonary fibrosis, and was associated with a slower FVC decline in those with progressive pulmonary fibrosis. Nintedanib was also associated with a slower FVC decline and increased mean survival in people with ILD. The immunomodulator tocilizumab has a benefit in scleroderma associated ILD by helping to preserve lung function (as measured by FVC) at 48 weeks. The immunomodulators cyclophosphamide, mycophenolate mofetil and rituximab all showed improved lung function (as measured by % predicted FVC) compared to placebo in systemic sclerosis or scleroderma associated ILD. The inhaled vasodilator treprostinil (a synthetic prostacyclin which acts as a prostaglandin I2 analogue) is indicated in the treatment of pulmonary hypertension secondary to interstitial lung disease and is associated with improved exercise capacity as measured by a 6-minute walk test.
Sources: en.wikipedia.org
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。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.