A practical reference on Pro-Gly-Pro tail: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-10-09 and is reviewed periodically as new material appears.
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 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.
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
== Legacy == Freeman was principally responsible for the establishment of structural biology as a discipline in Australia. He founded the first protein crystallography laboratory in Australia; by the time of his death, there were at least 15 active research groups carrying out protein crystallography in Australia and New Zealand. Many former members of the Freeman research group have moved on to join one of these other groups. The groups interact through the Society of Crystallographers of Australia and New Zealand (SCANZ); Freeman was instrumental in forming the organisation (then called the Society of Crystallographers of Australia) in 1976, and was its Foundation President. Working as a crystallographer, Freeman's major legacies are the understanding of plastocyanin and other blue copper proteins, and development of the MAD method as an extension of EXAFS spectroscopy. Freeman's work in ensuring Australian scientists have access to "big science" facilities will continue to assist researchers into the future. His teaching also leaves a legacy of "generations of students imbued with a love of science".
A central Food Production Committee, set up in early 1942, organised the conscripted labourers and attempted to help the white farmers to grow all the crops they could. Maize production grew by 40% between 1942 and 1944, the potato harvest doubled and the onion crop grew sixfold by the end of the war. Production of the colony's most important cash crop, tobacco, was high throughout the war, averaging about 40 million pounds (18 million kg) annually. The number of cattle slaughtered by the beef industry increased by 134%, from 71,000 head in 1937 to 160,000 head in 1945. Vegetable dehydration, one of the Food Production Committee's main initiatives, proved a great success, allowing Rhodesia to export many products to the UK that would previously have spoiled in transit. Southern Rhodesia also provided goods to the Eastern Group Supply Council, a body set up in 1940 to co-ordinate the build-up of war materiel in India and other British colonies and dominions east of Suez, with the goal of reducing the amount of supplies shipped from the UK. A Rhodesian officer, Brigadier E G Cook, was the group's deputy controller general. Between 1941 and 1945 Southern Rhodesia contributed large quantities of timber, leather goods, soap and building materials.
Body fat cells have regional responses to the overfeeding that was studied in adult subjects. In the upper body, an increase of adipocyte size correlated with upper-body fat gain; however, the number of fat cells was not significantly changed. In contrast to the upper body fat cell response, the number of lower-body adipocytes did significantly increase during the course of experiment. Notably, there was no change in the size of the lower-body adipocytes. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index without a significant increase in the overall number of adipocytes in adulthood.
== Forums == Bodybuilding.com once had the most popular Internet forums dedicated to fitness discussion. After its closure, Aftermath's Chris Person wrote that in the history of forums, it "was so gargantuan it barely needs mentioning". As of 2022, 18 million people used them, making them one of the last remaining, popular Web 1.0 forums. They were known for having a large amount of trolling; a politically diverse userbase (notable in comparison to other forums like right-wing 4chan); and expansive discussion of subjects unrelated to fitness, in the Misc. (miscellaneous) subforum. Users of the subforum were known as "Miscers". In health-related posts, users often logged their workouts, signed up for bodybuilding challenges made by others, reviewed supplements, and gave others motivational support. Notable users included WWE wrestler Lars Sullivan; bodybuilder Zyzz (who died of cardiac arrest in 2011, possibly from anabolic steroid use); and Elliot Rodger, the perpetrator of the 2014 Isla Vista killings. In 2014, the forums popularized the word "nutting" as slang for ejaculation. The forums were involved in many controversies. In 2008, a man named Abraham Biggs died of suicide after being bullied on the site. He livestreamed his suicide on Justin.tv, and posted a link to the stream on the forums beforehand. In 2011, user ThePoz discovered an exploit that allowed anyone to access private photographs of Facebook CEO Mark Zuckerberg on the Facebook site itself, then publicized the method on the forums.
According to a 11 January 2019 article in Haaretz, Justice Esther Hayut, the President of the High Court of Justice, announced that eleven justices would be debating the "legality" of the July 2018 Basic Law: Israel as the Nation-State of the Jewish People, also known as the Nation-state law, including its "historical stipulations".
Sources: en.wikipedia.org
MRI has the advantages of having very high spatial resolution and is very adept at morphological imaging and functional imaging. MRI does have several disadvantages though. First, MRI has a sensitivity of around 10−3 mol/L to 10−5 mol/L, which, compared to other types of imaging, can be very limiting. This problem stems from the fact that the population difference between the nuclear spin states is very small at room temperature. For example, at 1.5 teslas, a typical field strength for clinical MRI, the difference between high and low energy states is approximately 9 molecules per 2 million. Improvements to increase MR sensitivity include increasing magnetic field strength and hyperpolarization via optical pumping or dynamic nuclear polarization. There are also a variety of signal amplification schemes based on chemical exchange that increase sensitivity. To achieve molecular imaging of disease biomarkers using MRI, targeted MRI contrast agents with high specificity and high relaxivity (sensitivity) are required. To date, many studies have been devoted to developing targeted-MRI contrast agents to achieve molecular imaging by MRI. Commonly, peptides, antibodies, or small ligands, and small protein domains, such as HER-2 affibodies, have been applied to achieve targeting. To enhance the sensitivity of the contrast agents, these targeting moieties are usually linked to high payload MRI contrast agents or MRI contrast agents with high relaxivities.
All white, male residents aged eighteen to twenty-three were obligated to fulfil four and a half months (later extended to nine months) of full-time national service. This was followed by a three-year reservist obligation. By 1974, the national service intakes had been doubled, and white men over twenty-three were also conscripted. In 1978, the Rhodesian Army had about 14,000 white national servicemen, but continued manpower shortages forced it to recruit black volunteers in larger numbers and extend compulsory military service to all white males up to sixty years of age. By the end of the Rhodesian Bush War virtually all male white residents were either serving in the military or police in a full-time or part-time capacity. The size of the Rhodesian Army had swelled to about 20,000 personnel, and the BSAP to over 40,000, including reservists.
Spatial and temporal control of substrate labeling has been investigated using photoactivatable cyclooctynes. This allows equilibration of the alkyne prior to reaction in order to reduce artifacts as a result of concentration gradients. Masked cyclooctynes are unable to react with azides in the dark but become reactive alkynes upon irradiation with light.
Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing reticulin prior to counting. Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional.
Sources: en.wikipedia.org
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.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
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.