Everything below concerns RP-HPLC purity. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-05-05. Numbers and descriptions here follow the published literature rather than marketing material.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Gunston, Bill. An Illustrated Guide to Allied Fighters of World War II. London: Salamander Books Ltd, 1981. ISBN 0-668-05228-7. Gunston, Bill. Aerei della seconda guerra mondiale (in Italian). Milan: Peruzzo editore, 1984. No ISBN. Gunston, Bill and Mike Spick. Modern Air Combat. Crescent Books, 1983, ISBN 91-972803-8-0. Gunston, Bill. North American P-51 Mustang. New York: Gallery Books, 1990. ISBN 0-8317-1402-6. Gunston, Bill and Robert F. Dorr. "North American P-51 Mustang: The Fighter That Won the War." Wings of Fame, Volume 1. London: Aerospace, 1995, pp. 56–115. ISBN 1-874023-74-3. Hagedorn, Dan. Central American and Caribbean Air Forces. Tonbridge, Kent, UK: Air-Britain (Historians), 1993. ISBN 0-85130-210-6. Hagedorn, Dan. Latin American Air Wars & Aircraft. Crowborough, UK: Hikoki, 2006. ISBN 1-902109-44-9. Hammond, Grant. The Mind of War: John Boyd and American Security, Smithsonian Institution Press, 2001, ISBN 1-56098-941-6. Hastings, Max. Bomber Command. Minneapolis, Minnesota: Zenith Press, 1979. ISBN 978-0-76034-520-7. Hatch, Gardner N.; Winter, Frank H. (1993). P-51 Mustang. Paducah, KY: Turner Publishing Company. ISBN 978-1-56311-080-1. Hess, William N. Fighting Mustang: The Chronicle of the P-51. New York: Doubleday and Company, 1970. ISBN 0-912173-04-1. "History, Boeing: P-51 Mustang". Boeing. Retrieved: 24 June 2014. Jackson, Robert. Aircraft of World War II: Development, Weaponry, Specifications. Edison, New Jersey: Chartwell Books, 2003. ISBN 0-7858-1696-8. Jackson, Robert. Mustang: The Operational Record.
=== Participation === Individuals with dwarfism are capable of actively participating in various aspects of society. They have access to education and sports, and can pursue careers, engaging in a wide range of professions.
As of 2014, low-end refurbished 60 MHz and 90 MHz systems were sold as FT–NMR instruments, and in 2010 the "average workhorse" NMR instrument was configured for 300 MHz. CW spectroscopy is inefficient in comparison with Fourier analysis techniques (see below) since it probes the NMR response at individual frequencies or field strengths in succession. Since the NMR signal is intrinsically weak, the observed spectrum suffers from a poor signal-to-noise ratio. This can be mitigated by signal averaging, i.e. adding the spectra from repeated measurements. While the NMR signal is the same in each scan and so adds linearly, the random noise adds more slowly – proportional to the square root of the number of spectra added (see random walk). Hence the overall signal-to-noise ratio increases as the square-root of the number of spectra measured. However, monitoring an NMR signal at a single frequency as a function of time may be better suited for kinetic studies than pulsed Fourier-transform NMR spectrosocopy.
Sources: en.wikipedia.org
== External links == Histology image: 14805loa – Histology Learning System at Boston University Anatomy photo: Reproductive/mammal/ovary2/ovary5 - Comparative Organology at University of California, Davis - "Mammal, canine ovary (LM, High)" Anatomy photo: Reproductive/mammal/ovary5/ovary6 - Comparative Organology at University of California, Davis - "Mammal, bovine ovary (LM, Medium)" Anatomy Atlases – Microscopic Anatomy, plate 13.249 Slide at trinity.edu
== 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.
== Membership == In 1975, chairman Frank Zeidler claimed that SPUSA had around 500 members nationwide. SPUSA saw growth during the late 1970s and early to mid-1980s, expanding from around 600 members to around 1,700 members. In 2008, WMNF claimed that SPUSA had around 3,000 members. However, in 2010, CommonDreams wrote that SPUSA had only 1,000 members, and party members described that as an increase in membership. In May 2011, The New York Times stated that SPUSA had "about 1,000 members nationally". In February 2012, The Root stated that SPUSA had "around 1,500" members.
The complete fosfomycin biosynthetic gene cluster from Streptomyces fradiae has been cloned and sequenced and the heterologous production of fosfomycin in S. lividans has been achieved by Ryan Woodyer of the Huimin Zhao and Wilfred van der Donk research groups.
Sources: en.wikipedia.org
== Biosynthesis == CDPS-encoding genes are found in genomic locations with genes encoding additional biosynthetic enzymes (CDPS DmtB1 is an example, encoded by the gene of dmt1 locus). These additional biosynthetic enzymes are for example: oxidoreductases, prenyltransferases, methyltransferases, or cyclases and some proteins as cytochrome P450s.
The AAA pathway involves the condensation of α-ketoglutarate and acetyl-CoA via the intermediate AAA for the synthesis of L-lysine. This pathway has been shown to be present in several yeast species, as well as protists and higher fungi. It has also been reported that an alternative variant of the AAA route has been found in Thermus thermophilus and Pyrococcus horikoshii, which could indicate that this pathway is more widely spread in prokaryotes than originally proposed. The first and rate-limiting step in the AAA pathway is the condensation reaction between acetyl-CoA and α‑ketoglutarate catalysed by homocitrate-synthase (HCS) (E.C 2.3.3.14) to give the intermediate homocitryl‑CoA, which is hydrolysed by the same enzyme to produce homocitrate. Homocitrate is enzymatically dehydrated by homoaconitase (HAc) (E.C 4.2.1.36) to yield cis-homoaconitate. HAc then catalyses a second reaction in which cis-homoaconitate undergoes rehydration to produce homoisocitrate. The resulting product undergoes an oxidative decarboxylation by homoisocitrate dehydrogenase (HIDH) (E.C 1.1.1.87) to yield α‑ketoadipate. AAA is then formed via a pyridoxal 5′-phosphate (PLP)-dependent aminotransferase (PLP-AT) (E.C 2.6.1.39), using glutamate as the amino donor. From this point on, the AAA pathway varies with [something is missing here ? -> at the very least, section header! ] on the kingdom.
The progenitor of the Samoyeds was the Nenets Herding Laika, a reindeer herding spitz commonly used throughout the Arctic, especially the Nenets people, who were pejoratively referred to as Samoyeds at that time. DNA evidence confirms that Samoyeds are a basal breed that predates the emergence of the modern breeds in the 19th century. A genomic study of two dog specimens nearly 100 years old obtained from the Nenets people on the Yamal Peninsula found that these are related to two specimens dated 2,000 years old and 850 years old, which suggests continuity of the lineage in this region. The two 100-year-old dogs were closely related with the Samoyed breed, which indicates that the ancient Arctic lineage lives on in the modern Samoyed dog.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.