The short version of melanocortin signalling fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-10-28 and is reviewed periodically as new material appears.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Mammals are a clade, and therefore the cladists are happy to acknowledge the traditional taxon Mammalia; and birds, too, are a clade, universally ascribed to the formal taxon Aves. Mammalia and Aves are, in fact, subclades within the grand clade of the Amniota. But the traditional class Reptilia is not a clade. It is just a section of the clade Amniota: The section that is left after the Mammalia and Aves have been hived off. It cannot be defined by synapomorphies, as is the proper way. Instead, it is defined by a combination of the features it has and the features it lacks: reptiles are the amniotes that lack fur or feathers. At best, the cladists suggest, we could say that the traditional Reptilia are 'non-avian, non-mammalian amniotes'. Despite the early proposals for replacing the paraphyletic Reptilia with a monophyletic Sauropsida, which includes birds, that term was never adopted widely or, when it was, was not applied consistently.
== Tissue distribution == IGFBP-3 mRNA is expressed in all tissue examined, with kidney, stomach, placenta, uterus and liver showing highest expression in rat tissues. Rat liver IGFBP-3 mRNA is found in nonparenchymal cells including sinusoidal endothelium, but not in hepatocytes. In contrast, human hepatocytes do express IGFBP-3.
DOTA-TATE (DOTATATE, DOTA-octreotate, oxodotreotide, DOTA-(Tyr3)-octreotate, and DOTA-0-Tyr3-Octreotate) is an eight amino acid long peptide, with a covalently bonded DOTA bifunctional chelator. DOTA-TATE can be reacted with the radionuclides gallium-68 (T1/2 = 68 min), lutetium-177 (T1/2 = 6.65 d) and copper-64 (T1/2 = 12.7 h) to form radiopharmaceuticals for positron emission tomography (PET) imaging or radionuclide therapy. 177Lu DOTA-TATE therapy is a form of peptide receptor radionuclide therapy (PRRT) which targets somatostatin receptors (SSR). In that form of application it is a form of targeted drug delivery.
A seismic metamaterial is a metamaterial that is designed to counteract the adverse effects of seismic waves on artificial structures. Current designs of seismic metamaterials use configurations of boreholes, trees, or proposed underground resonators to act as a large-scale material. Experiments have observed both reflections and bandgap attenuation from artificially induced seismic waves. These are the first experiments to verify that seismic metamaterials can be measured for frequencies below 100 Hz, where damage from Rayleigh waves is the most harmful to artificial structures.
Where duties are partially performed, at common law there is an obligation to pay for work accepted, unless the employer makes clear they will not accept partial performance, a position which encourages all out strikes and exacerbates disputes. Moreover, employers who cannot reasonably operate broken machinery, or is facing a closure from strikes, can stand down employees without pay. Even where industrial action is protected and valid, the FWC still has jurisdiction to suspend or terminate action if it threatens significant economic harm on application of a union or a federal or state Minister, if it threatens life, safety, health, welfare or part of the Australian economy, if a cooling off period would "assist in resolving the matters at issue", or if there is significant harm to a third party. For instance, in the 2011 Qantas industrial disputes, the Minister intervened to get a stop order to suspend a pilot strike at Qantas, given the impact on the national tourism industry. Secondary boycotts have been banned since 1977, so that unions cannot take action in solidarity with workers in different workplaces, even where anti-productive competition is driving pay down in a race to the bottom across a whole sector. The ban is enforceable by the Australian Competition and Consumer Commission regardless of whether the parties to a dispute pursue a complaint. It is not yet clear that self-employed workers have the right to take collective action, although under international law, the right to act and strike is guaranteed for "everyone".
Sources: en.wikipedia.org
=== Bombay blood === Also known as hh blood group, this rare blood type cannot receive blood from any of the ABO blood group, and must receive hh blood from either another person with this condition or themselves (autologous transfusions).
=== Other === The muscles that control breathing and limb movements can also be affected; rarely do these present as the first symptoms of myasthenia gravis, but develop over months to years. In a myasthenic crisis, a paralysis of the respiratory muscles occurs, necessitating assisted ventilation to sustain life. Crises may be triggered by various biological stressors such as infection, fever, an adverse reaction to medication, or emotional stress.
In contrast to product requirements or other laws that hinder market access, the Court of Justice developed a presumption that "selling arrangements" would be presumed to not fall into TFEU article 34, if they applied equally to all sellers, and affected them in the same manner in fact. In Keck and Mithouard two importers claimed that their prosecution under a French competition law, which prevented them selling Picon beer under wholesale price, was unlawful. The aim of the law was to prevent cut throat competition, not to hinder trade. The Court of Justice held, as "in law and in fact" it was an equally applicable "selling arrangement" (not something that alters a product's content) it was outside the scope of article 34, and so did not need to be justified. Selling arrangements can be held to have an unequal effect "in fact" particularly where traders from another member state are seeking to break into the market, but there are restrictions on advertising and marketing. In Konsumentombudsmannen v De Agostini the Court of Justice reviewed Swedish bans on advertising to children under age 12, and misleading commercials for skin care products. While the bans have remained (justifiable under article 36 or as a mandatory requirement) the Court emphasised that complete marketing bans could be disproportionate if advertising were "the only effective form of promotion enabling [a trader] to penetrate" the market.
On 20 January, the Brazilian Ministry of Health declared a national emergency following reports of deaths among Yamomami children due to malnutrition and easily curable diseases. The president of the FUNAI also led the creation of a task force to deal with the humanitarian crisis. Between 2019 and 2023, at least of 570 Yanomami children died from malnutrition, hunger and mercury contamination. Lula accused Jair Bolsonaro's government of having committed genocide against the Yanomami, several researchers blamed the entry of illegal miners into protected native lands for the high amount of deaths between the local indigenous peoples, as well as alleged connivance and omission of the federal and local/state administrations during the previous government. Due to the high number of deaths since 2023, reports on the situation decreased, until they stopped being published at the beginning of 2024, when there was a further increase in deaths due to violence.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.