Everything below concerns ACTH 片段. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
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.
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 |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid from research suppliers |
| Solubility | Freely soluble in water | Also dissolves in aqueous buffers; solutions are used fresh |
| Typical storage temperature | -20 °C for lyophilized powder | Short-term transport at 2-8 °C is common |
| Common analytical method | Reverse-phase HPLC | Paired with mass spectrometry for identity confirmation |
| Common synonyms | ACTH(4-10) analogue; MEHFPGP | N-terminal methionine retained in the chain |
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
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.
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。
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。
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。
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。
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
== Physiology == Biochemically, hippuric acid is produced from benzoic acid and glycine, which occurs in the liver, intestine, and kidneys. In terms of mechanism, benzoic acid is converted to benzoyl CoA, an acylating agent. Hippuric acid may be formed from the essential amino acid phenylalanine through at least two pathways. Phenylalanine undergoes biotransformation to form an alpha-keto acid, phenylpyruvic acid, which can tautomerize to a reactive enol. The benzylic carbon is reactive which undergoes peroxidation followed by the competing pathways to either react with the alpha carbon subsequently form an dioxetanol intermediate followed by formation of oxalic acid and benzaldehyde, or, peroxidation can react with the carboxyl group to form an alpha-keto-beta-peroxylactone intermediate followed by formation of carbon monoxide, carbon dioxide, and benzaldehyde. Alternatively, under certain conditions, phenylpyruvic acid may undergo a redox mechanism, such as Iron(II) donating an electron, to directly release carbon dioxide, followed by carbon monoxide, for the formation of a stable toluene radical which is resolved by an antioxidant such as ascorbate. In all of the aforementioned cases, benzaldehyde undergoes biotransformation via CYP450 to benzoic acid followed by conjugation to glycine for formation of hippurate which undergoes urinary excretion. Similarly, toluene reacts with CYP450 to form benzaldehyde. Hippuric acid has been reported to be a marker for Parkinson's disease.
When purifying proteins, alkalies such as sodium hydroxide (NaOH) can be used safely and effectively. It is also widely used for depyrogenation of non-autoclavable equipment (e.g. plastics) and chromatography columns. In fact, when using an anion exchanger to remove pyrogens, it is necessary to clean the column with NaOH after each batch.
However, after the Qualifying Final between Collingwood and West Coast was drawn and replayed, Essendon lost to Collingwood in both the second semi-final and the grand final. Following the 1991 season, Essendon moved its home games from its traditional home ground at Windy Hill to the larger and newly renovated MCG. This move generated large increases in game attendances, memberships and revenue for the club. The club's training and administrative base remained at Windy Hill until 2013. Following the retirement of Tim Watson and Simon Madden in the early 1990s, the team was built on new players such as Gavin Wanganeen, Joe Misiti, Mark Mercuri, Michael Long, Dustin Fletcher (son of Ken) and James Hird, who was taken at No. 79 in the 1990 draft. This side became known as the "Baby Bombers", as the core of the 1993 premiership side was made up of young players early in their careers. The team won the 1993 Grand Final against Carlton and that same year, Gavin Wanganeen won the Brownlow Medal, the first awarded to an Essendon player since 1976. Three years later, James Hird was jointly awarded the medal with Michael Voss of Brisbane. In 2000, the club shifted the majority of its home games to the newly opened Docklands Stadium, signing a 25-year deal to play seven home matches per year at the venue, with the other four remaining at the MCG. The season was one of the most successful by any team in VFL/AFL history, and the club opened with 20 consecutive wins before they lost to the Western Bulldogs in round 21.
Sources: en.wikipedia.org
== Legal status == Thebacon is a Schedule I controlled substance in the United States, never having been in medical use there. The US DEA Administrative Controlled Substance Control Number assigned by the Controlled Substances Act (1970) for thebacon and all of its salts is 9315.
Natural strontium is a mixture of four stable isotopes: 84Sr, 86Sr, 87Sr, and 88Sr. Of these isotopes, 88Sr is the most abundant, making up about 82.6% of all natural strontium, though the abundance varies somewhat due to the production of radiogenic 87Sr as the daughter of long-lived beta-decaying 87Rb. This is the basis of rubidium–strontium dating. Of the unstable isotopes, the primary decay mode of the isotopes lighter than 86Sr is electron capture or positron emission to isotopes of rubidium, and that of the isotopes heavier than 88Sr is electron emission to isotopes of yttrium. Of special note are 89Sr and 90Sr. The former has a half-life of 50.56 days and is used to treat bone cancer due to strontium's chemical similarity and hence ability to replace calcium. While 90Sr (half-life 28.91 years) has been used similarly, it is more an isotope of concern in fallout from nuclear weapons and nuclear accidents due to its longer life (both are produced as fission products). Its presence in bones, where all strontium accumulates, can cause bone cancer, cancer of nearby tissues, and leukemia. The 1986 Chernobyl nuclear accident contaminated about 30,000 km2 with greater than 10 kBq/m2 of 90Sr, or an estimated 5% of the reactor's total content of 90Sr.
== History == Cellulose was discovered in 1838 by the French chemist Anselme Payen, who isolated it from plant matter and determined its chemical formula. Cellulose was used to produce the first successful thermoplastic polymer, celluloid, by Hyatt Manufacturing Company in 1870. Production of rayon ("artificial silk") from cellulose began in the 1890s and cellophane was invented in 1912. Hermann Staudinger determined the polymer structure of cellulose in 1920. The compound was first chemically synthesized (without the use of any biologically derived enzymes) in 1992, by Kobayashi and Shoda.
Manufacture of lysosomal enzymes with a mannose-6-phosphate marker added in the cis-Golgi network. Manufacture of secreted proteins, either secreted constitutively with no tag or secreted in a regulatory manner involving clathrin and paired basic amino acids in the signal peptide. Integral membrane proteins that stay embedded in the membrane as vesicles exit and bind to new membranes. Rab proteins are key in targeting the membrane; SNAP and SNARE proteins are key in the fusion event. Initial glycosylation as assembly continues. This is N-linked (O-linking occurs in the Golgi). N-linked glycosylation: If the protein is properly folded, oligosaccharyltransferase recognizes the AA sequence NXS or NXT (with the S/T residue phosphorylated) and adds a 14-sugar backbone (2-N-acetylglucosamine, 9-branching mannose, and 3-glucose at the end) to the side-chain nitrogen of Asn. The RER has ribosomes while the SER does not.
Sources: en.wikipedia.org
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.
A fraction of an intranasal dose is thought to reach the central nervous system, and this route is favoured partly for that reason. The proportion is not well characterized. Direct measurement in humans remains difficult with current methods.
Raised BDNF and NGF expression has been reported across several animal studies, which makes the signal fairly consistent. Whether the same change occurs in humans at usable doses is not established. It is best treated as a working hypothesis rather than a confirmed clinical mechanism.
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.