Heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-17. Anything still debated is marked as such rather than presented as settled.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
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.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
== Isolation and synthesis == Vinblastine may be isolated from the Madagascar Periwinkle (Catharanthus roseus), its only known biological producer, along with several of its precursors, catharanthine and vindoline. Extraction is costly and yields of vinblastine and its precursors are low, although procedures for rapid isolation with improved yields avoiding auto-oxidation have been developed. Enantioselective synthesis has been of considerable interest in recent years, as the natural mixture of isomers is not an economical source for the required C16'S, C14'R stereochemistry of biologically active vinblastine. Initially, the approach depends upon an enantioselective Sharpless epoxidation, which sets the stereochemistry at C20. The desired configuration around C16 and C14 can then be fixed during the ensuing steps. In this pathway, vinblastine is constructed by a series of cyclization and coupling reactions which create the required stereochemistry. The overall yield may be as great as 22%, which makes this synthetic approach more attractive than extraction from natural sources, whose overall yield is about 10%. Stereochemistry is controlled through a mixture of chiral agents (Sharpless catalysts), and reaction conditions (temperature, and selected enantiopure starting materials). Due to difficulty of stereochemical restraints in total synthetic processes, other semi-synthetic methods from precursors, catharanthine and vindoline, continue to be developed.
=== March === 8 March The report of a 20-year survey by The Botanical Society of Britain and Ireland revealed that 56% of Ireland's native plant species are in decline due to habitat loss, altered grazing pressure, and degradation (re-seeding, over-fertilising, nitrogen deposition, herbicides, soil drainage, mineral enrichment), rather than rising temperatures whose botanical effects – so far – are minor. By contrast, 80% of non-native plants introduced into Ireland since 1500 have increased. The Taoiseach Leo Varadkar marked International Women's Day by announcing the Government's intention to hold a referendum to enshrine gender equality in the Constitution by amending Articles 40 and 41. 13 March – President of the United States Joe Biden announced that he will visit Ireland, north and south, in April for the 25th anniversary of the Good Friday Agreement (signed on 10 April 1998). It was reported two weeks later that Biden will arrive in Belfast on 11 April, then he will be based in Dublin from 12 to 15 April from where he will make trips to other parts of the country. Former US president Bill Clinton and his wife Hillary will visit Belfast the following week. 15 March – 46-year-old Stephen Silver was found guilty of the capital murder of Detective Garda Colm Horkan who was shot dead in Castlerea, County Roscommon in June 2020. 16 March – Ryan Tubridy announced that he would be stepping down as the presenter of The Late Late Show after 14 years, with his last show in May.
Low density lipoprotein receptor-related protein 1 (LRP1), also known as alpha-2-macroglobulin receptor (A2MR), apolipoprotein E receptor (APOER) or cluster of differentiation 91 (CD91), is a protein forming a receptor found in the plasma membrane of cells involved in receptor-mediated endocytosis. In humans, the LRP1 protein is encoded by the LRP1 gene. LRP1 is also a key signalling protein and, thus, involved in various biological processes, such as lipoprotein metabolism and cell motility, and diseases, such as neurodegenerative diseases, atherosclerosis, and cancer.
Sources: en.wikipedia.org
== Pharmacology == Semax is a heptapeptide and synthetic analogue of a fragment of adrenocorticotropic hormone (ACTH), ACTH (4-10), of the following amino acid sequence: Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP in single-letter form). In animals, Semax rapidly elevates the levels and expression of brain-derived neurotrophic factor (BDNF) and its signaling receptor tropomyosin receptor kinase B (TrkB) in the hippocampus, and rapidly activates serotonergic and dopaminergic brain systems. Accordingly, it has been found to produce antidepressant-like and anxiolytic-like effects, attenuate the behavioral effects of exposure to chronic stress, and potentiate the locomotor activity produced by D-amphetamine. As such, it has been suggested that Semax may be effective in the treatment of depression. Though the exact mechanism of action of Semax is unclear, there is evidence that it may act through melanocortin receptors. Specifically, there is a report of Semax competitively antagonizing the action of α-melanocyte-stimulating hormone (α-MSH) at the MC4 and MC5 receptors in both in vitro and in vivo experimental conditions, indicating that it may act as an antagonist or partial agonist of these receptors. (&alpha-MSH acts as a full agonist of all five melanocortin receptors). Semax did not antagonize α-MSH at the MC3 receptor, though this receptor could still be a target of the drug. As for the MC1 and MC2 receptors, they were not assayed.
== Rhabdomyolysis == Exertional rhabdomyolysis is an extreme and potentially deadly form of overtraining that leads to a breakdown of skeletal muscle which makes its way into the blood. Many molecules such as potassium, creatine kinase, phosphate, and myoglobin are released into circulation. Myoglobin is the protein that causes the lethal reaction in the body. Early detection of the syndrome is essential in full recovery. A serious late complication of rhabdomyolysis which occurs in 15% of the population is acute kidney injury, and in some cases it can lead to death.
1993/2131) Courts and Legal Services Act 1990 (Commencement No. 9) Order 1993 (S.I. 1993/2132) Rules of the Supreme Court (Amendment) 1993 (S.I. 1993/2133) Leasehold Reform, Housing and Urban Development Act 1993 (Commencement and Transitional Provisions No. 1) Order 1993 (S.I. 1993/2134) Edinburgh Assay Office (Amendment) Order 1993 (S.I. 1993/2135) County Court (Amendment No. 2) Rules 1993 (S.I. 1993/2150) Combined Probation Areas (Hertfordshire) Order 1993 (S.I. 1993/2151) Manchester, Liverpool Road (Castlefield Properties Limited) Light Railway Order 1993 (S.I. 1993/2153) East Kent Light Railway Order 1993 (S.I. 1993/2154) Mental Health (Nurses) Amendment Order 1993 (S.I. 1993/2155) Mental Health (Hospital, Guardianship and Consent to Treatment) Amendment Regulations 1993 (S.I. 1993/2156) Leasehold Reform, Housing and Urban Development Act 1993 (Commencement No. 2) (Scotland) Order 1993 (S.I. 1993/2163) Housing (Preservation of Right to Buy) (Scotland) Regulations 1993 (S.I. 1993/2164) Employment Protection (Continuity of Employment) Regulations 1993 (S.I. 1993/2165) Controlled Drugs (Substances Useful for Manufacture) (Intra–Community Trade) Regulations 1993 (S.I. 1993/2166) Tobacco Products (Amendment) Regulations 1993 (S.I. 1993/2167) A45/A452 Trunk Roads (Stonebridge Grade Separation) Order 1993 (S.I. 1993/2168) Education (Further Education Institutions Information) (Wales) Regulations 1993 (S.I. 1993/2169) A45 Trunk Road (Middle Bickenhill to Stonebridge) (De-Trunking) Order 1993 (S.I.
Sources: en.wikipedia.org
== Geography == Perhaps partly because the range runs through large portions of both the United States and Canada, and partly because the range was formed over numerous geologic time periods, one of which is sometimes termed the Appalachian orogeny, writing communities struggle to agree on an encyclopedic definition of the mountain range. However, each of the governments has an agency that informs the public about the major landforms that make up the countries, the United States Geological Survey (USGS) and the Geological Survey of Canada (GSC). The landforms are referred to as physiographic regions. The regions create precise boundaries from which maps can be drawn. The Appalachian Highlands is the name of one of the eight physiographic regions of the contiguous 48 United States. The Appalachian Uplands is the name of one of seven physiographic regions of Canada.
Solanine is a glycoalkaloid poison created by various plants in the genus Solanum, such as the potato plant. When the plant's stem, tubers, or leaves are exposed to sunlight, it stimulates the biosynthesis of solanine and other glycoalkaloids as a defense mechanism so it is not eaten. It is therefore considered to be a natural pesticide. Though the structures of the intermediates in this biosynthetic pathway are shown, many of the specific enzymes involved in these chemical processes are not known. However, it is known that in the biosynthesis of solanine, cholesterol is first converted into the steroidal alkaloid solanidine. This is accomplished through a series of hydroxylation, transamination, oxidation, cyclization, dehydration, and reduction reactions. Specifically, solanidine formation involves sequential hydroxylation, transamination, and cyclization reactions.The solanidine is then converted into solanine through a series of glycosylation reactions catalyzed by specific glycosyltransferases. Plants like the potato and tomato constantly synthesize low levels of glycoalkaloids like solanine. However, under stress, such as the presence of a pest or herbivore, they increase the synthesis of compounds like solanine as a natural chemical defense. This rapid increase in glycoalkaloid concentration gives the potatoes a bitter taste, and stressful stimuli like light also stimulate photosynthesis and the accumulation of chlorophyll. As a result, the potatoes turn green, and are thus unattractive to pests.
=== 19th century === In 1878, Lilly hired his brother, James, as his first full-time salesman, and the subsequent sales team marketed the company's drugs nationally. By 1879, the company had grown to $48,000 in sales. The company moved its Indianapolis headquarters from Pearl Street to larger quarters at 36 South Meridian Street. In 1881, the company moved to its current headquarters in Indianapolis's south-side industrial area, and the company later purchased additional facilities for research and production. The same year, Lilly incorporated the business as Eli Lilly and Company, elected a board of directors, and issued stock to family members and close associates. Lilly's first innovative product was gelatin-coating for pills and capsules. The company's other early innovations included fruit flavorings and sugarcoated pills, which made the medicines easier to swallow. In 1882, Colonel Lilly's only son, Josiah K. Lilly Sr. (J. K.), a pharmaceutical chemist, graduated from the Philadelphia College of Pharmacy in Philadelphia, and returned to Indianapolis to join the family business as a superintendent of its laboratory. In 1883, the company contracted to mix and sell Succus Alteran, its first widely successful product and one its best sellers. The product was marketed as a "blood purifier" and as a treatment for syphilis, some types of rheumatism, and skin diseases such as eczema and psoriasis. By the late 1880s, Colonel Lilly was one of the Indianapolis area's leading businessmen, and the company had over 100 employees and $200,000 in annual sales.
Thyrotropin-releasing hormone has a stimulatory effect on prolactin release, although prolactin is the only anterior pituitary hormone whose principal control is inhibitory. Several variants and forms are known per species. Many fish have variants prolactin A and prolactin B. Most vertebrates, including humans, also have the closely related somatolactin. In humans, 14, 16, and 22 kDa variants exist.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.