Melanocortin receptor 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.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
Integral polytopic proteins are transmembrane proteins that span across the membrane more than once. These proteins may have different transmembrane topology. These proteins have one of two structural architectures: Helix bundle proteins, which are present in all types of biological membranes; Beta barrel proteins, which are found only in outer membranes of Gram-negative bacteria, and outer membranes of mitochondria and chloroplasts. Bitopic proteins are transmembrane proteins that span across the membrane only once. Transmembrane helices from these proteins have significantly different amino acid distributions to transmembrane helices from polytopic proteins. Integral monotopic proteins are integral membrane proteins that are attached to only one side of the membrane and do not span the whole way across.
Secondly, elements 104 and 105 were given names favored by JINR, despite earlier recognition of LBL as an equal co-discoverer for both of them. Thirdly and most importantly, IUPAC rejected the name seaborgium for element 106, having just approved a rule that an element could not be named after a living person, even though the 1993 report had given the LBL team the sole credit for its discovery. In 1995, IUPAC abandoned the controversial rule and established a committee of national representatives aimed at finding a compromise. They suggested seaborgium for element 106 in exchange for the removal of all the other American proposals, except for the established name lawrencium for element 103. The equally entrenched name nobelium for element 102 was replaced by flerovium after Georgy Flerov, following the recognition by the 1993 report that that element had been first synthesized in Dubna. This was rejected by American scientists and the decision was retracted. The name flerovium was later used for element 114. In 1996, IUPAC held another meeting, reconsidered all names in hand, and accepted another set of recommendations; it was approved and published in 1997. Element 105 was named dubnium (Db), after Dubna in Russia, the location of the JINR; the American suggestions were used for elements 102, 103, 104, and 106. The name dubnium had been used for element 104 in the previous IUPAC recommendation. The American scientists "reluctantly" approved this decision.
=== Insect === The Drosophila melanogaster genome contains 29 serpin encoding genes. Amino acid sequence analysis has placed 14 of these serpins in serpin clade Q and three in serpin clade K with the remaining twelve classified as orphan serpins not belonging to any clade. The clade classification system is difficult to use for Drosophila serpins and instead a nomenclature system has been adopted that is based on the position of serpin genes on the Drosophila chromosomes. Thirteen of the Drosophila serpins occur as isolated genes in the genome (including Serpin-27A, see below), with the remaining 16 organised into five gene clusters that occur at chromosome positions 28D (2 serpins), 42D (5 serpins), 43A (4 serpins), 77B (3 serpins) and 88E (2 serpins). Studies on Drosophila serpins reveal that Serpin-27A inhibits the Easter protease (the final protease in the Nudel, Gastrulation Defective, Snake and Easter proteolytic cascade) and thus controls dorsoventral patterning. Easter functions to cleave Spätzle (a chemokine-type ligand), which results in toll-mediated signaling. As well as its central role in embryonic patterning, toll signaling is also important for the innate immune response in insects. Accordingly, serpin-27A also functions to control the insect immune response. In Tenebrio molitor (a large beetle), a protein (SPN93) comprising two discrete tandem serpin domains functions to regulate the toll proteolytic cascade. Serpins have been found in tick saliva, suppressing T lymphocyte production and inhibiting expression of TNF-α, IFN-γ, and IL-6.
== Pharmacokinetics == Icodextrin is not significantly metabolised inside the peritoneum. Instead, it is absorbed slowly (40% after 12 hours) into the bloodstream via the lymph vessels. There it is broken down into oligosaccharides by the enzyme alpha-amylase. In patients with intact kidney function, both icodextrin and its fragments are excreted via the kidney by glomerular filtration.
Sources: en.wikipedia.org
=== The Hagedorn Prize === The Hagedorn Prize, named after Hans Christian Hagedorn, celebrates achievements in the understanding and treatment of diabetes. Hagedorn's work significantly advanced the quality of insulin production and diabetes care, making this award a tribute to his legacy in the field. The Hagedorn Prize is recognised as the most prestigious award in Internal Medicine in Denmark.. Hagedorn died in 1971 at age 83.
== Types of reactions == An exergonic reaction is a spontaneous chemical reaction that releases energy. It is thermodynamically favored, indexed by a negative value of ΔG (Gibbs free energy). Over the course of a reaction, energy needs to be put in, and this activation energy drives the reactants from a stable state to a highly energetically unstable transition state to a more stable state that is lower in energy (see: reaction coordinate). The reactants are usually complex molecules that are broken into simpler products. The entire reaction is usually catabolic. The release of energy (called Gibbs free energy) is negative (i.e. −ΔG) because energy is released from the reactants to the products. An endergonic reaction is an anabolic chemical reaction that consumes energy. It is the opposite of an exergonic reaction. It has a positive ΔG because it takes more energy to break the bonds of the reactant than the energy of the products offer, i.e. the products have weaker bonds than the reactants. Thus, endergonic reactions are thermodynamically unfavorable. Additionally, endergonic reactions are usually anabolic. The free energy (ΔG) gained or lost in a reaction can be calculated as follows: ΔG = ΔH − TΔS where ∆G = Gibbs free energy, ∆H = enthalpy, T = temperature (in kelvins), and ∆S = entropy.
== Reporting of yields == In their 2010 Synlett article, Martina Wernerova and organic chemist, Tomáš Hudlický, raised concerns about inaccurate reporting of yields, and offered solutions—including the proper characterization of compounds. After performing careful control experiments, Wernerova and Hudlický said that each physical manipulation (including extraction/washing, drying over desiccant, filtration, and column chromatography) results in a loss of yield of about 2%. Thus, isolated yields measured after standard aqueous workup and chromatographic purification should seldom exceed 94%. They called this phenomenon "yield inflation" and said that yield inflation had gradually crept upward in recent decades in chemistry literature. They attributed yield inflation to careless measurement of yield on reactions conducted on small scale, wishful thinking and a desire to report higher numbers for publication purposes.
== Research and career == Dunn-Walters has over a hundred primary research publications. She studies B cell development in disease, and how the immune system changes during ageing. She has developed new characterisation techniques to understand immune responses, including single-cell and repertoire approaches. She discovered IgM memory B cells in the spleen, that the older immune system has a less diverse repertoire of B cells, that there are at least 10 different types of B cells, that different types of B cells may have different repertoires and therefore be responding to different stimuli. She works in collaboration with computer scientists and together they have produced online tools for repertoire analysis. More recently, the development of new tools for distinguishing between productive and sterile transcripts of Ig constant region genes in B cells has shown that B cells become primed for Immunoglobulin class switching in a stage before they actually switch. She is part of the CARINA (Catalyst Reducing Immune Ageing) Network, a collective which looks to understand how ageing impacts the immune system and vice versa. Dunn-Walters has served on grants awarding and strategy committees for funding bodies such as the UK Research and Innovation (UKRI) MRC and BBSRC, Research Council of Norway, Fondazione Cariplo Italy. She is a member of the British Society for Research on Ageing where she has previously served on the board and as Programme Secretary.
=== Mass spectrometry === Ion funnels are frequently used in mass spectroscopy devices to collect ions from an ionization source. Previous devices lacking an ion funnel often lost ions during the transition from ionization source to the detector of the mass spectrometer. This loss was due to the increasing number of collisions undergone by ions with other gas molecules present in the atmosphere. The introduction of the ion funnel greatly reduced the amount of ions lost during experiments by guiding ions towards a desired destination, and through modification of the number of inlets is also able to increases sensitivity of measurements taken by the mass spectrometer. Multiple inlets allow multiple electrospray emitters, reducing the flow through each individual emitter. This creates many highly efficient electrosprays at low flow rates. Multiple inlets also improve sensitivity, with a linearly arranged 19 electrospray emitter coupled to 19 inlets operating at 18 Torr giving a nine-fold increase compared to a single inlet.
Sources: en.wikipedia.org
In Ethiopia, the Civil Aviation Accident Prevention and Investigation Bureau of the Ethiopian Civil Aviation Authority (ECAA), which is an agency of the Ministry of Transport and Communications, conducts aircraft accident investigations in Ethiopia or involving Ethiopian aircraft. In France, the agency responsible for investigation of civilian air crashes is the Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA). Its purpose is to establish the circumstances and causes of the accident and to make recommendations for their future avoidance. In Germany, the agency for investigating air crashes is the Federal Bureau of Aircraft Accidents Investigation (BFU). It is an agency of the Federal Ministry of Transport and Digital Infrastructure. The focus of the BFU is to improve safety by determining the causes of accidents and serious incidents and making safety recommendations to prevent recurrence.
At 3%, calcium is the fifth most abundant element in the Earth's crust, and the third most abundant metal behind aluminium and iron. It is also the fourth most abundant element in the lunar highlands. Sedimentary calcium carbonate deposits pervade the Earth's surface as fossilised remains of past marine life; they occur in two forms, the rhombohedral calcite (more common) and the orthorhombic aragonite (forming in more temperate seas). Minerals of the first type include limestone, dolomite, marble, chalk, and Iceland spar; aragonite beds make up the Bahamas, the Florida Keys, and the Red Sea basins. Corals, sea shells, and pearls are mostly made up of calcium carbonate. Among the other important minerals of calcium are gypsum (CaSO4·2H2O), anhydrite (CaSO4), fluorite (CaF2), and apatite ([Ca5(PO4)3X], X = OH, Cl, or F) The major producers of calcium are China (about 10000 to 12000 tonnes per year), Russia (about 6000 to 8000 tonnes per year), and the United States (about 2000 to 4000 tonnes per year). Canada and France are among the minor producers. In 2005, about 24000 tonnes of calcium were produced; about half of the world's extracted calcium is used by the United States, with about 80% of the output used each year. In Russia and China, Davy's method of electrolysis is still used, but is instead applied to molten calcium chloride. Since calcium is less reactive than strontium or barium, the oxide–nitride coating that results in air is stable and lathe machining and other standard metallurgical techniques are suitable for calcium. In the U.S.
4 On 21 December 1995, a major reshuffle took place amongst existing Ministers, mainly to discharge particular Ministers of portfolios which had proven troublesome for the government. 5 On 26 April 1996, George Cash resigned from the ministry due to ill health. Graham Kierath and Kevin Minson adopted his portfolios, whilst Norman Moore was elected leader of the Government in the Legislative Council four days later.
Most engineering materials show some nonlinear elastic and inelastic behavior under operating conditions that involve large loads. In such materials the assumptions of linear elastic fracture mechanics may not hold, that is,
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.