tuftsin raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-04-21. Anything still debated is marked as such rather than presented as settled.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
=== Other uses === The distinctive dried seed heads, which resemble the spouts of watering cans, are widely sold throughout the world for decorative purposes and for dried flower arranging. A unique fabric called lotus silk, from the lotus plant fibres, is produced only at Inle Lake, Myanmar, and in Siem Reap, Cambodia. This thread is used for weaving special robes for Buddha images called kya thingan (lotus robe).
The inauguration of Richard Nixon in January led to a reevaluation of the U.S. role in the war. U.S. forces peaked at 543,000 in April. U.S. military strategy remained relatively unchanged from the offensive strategy of 1968 until the Battle of Hamburger Hill in May which led to a change a more reactive approach. The U.S. and South Vietnam agreed on a policy of Vietnamization with South Vietnamese forces being expanded and equipped to take over more of the ground combat from the departing Americans which began to withdraw in late June without any reciprocal commitment by the North Vietnamese. The morale of U.S. ground forces began to fray with increasing racial tensions and the first instances of fragging and combat refusal. The antiwar movement in the U.S. continued to grow and public opinion turned increasingly antiwar when the Mỹ Lai massacre was revealed in November.
Prior to this, babies born in different states had received different levels of screening. On April 24, 2008, President George W. Bush signed into law the Newborn Screening Saves Lives Act of 2007. This act was enacted to increase awareness among parents, health professionals, and the public on testing newborns to identify certain disorders. It also sought to improve, expand, and enhance current newborn screening programs at the state level.
Sources: en.wikipedia.org
Positive social connections and interactions are further key elements of well-being. In addition to the intrinsic joy of engaging with others, social networks can offer material and emotional support during challenging times. They help people build trust, share values, promote the exchange of information, and provide access to new opportunities. Different types of social relationships may influence well-being in different ways, such as the contrasts between friends, family members, romantic partners, co-workers, and teammates. Researchers often focus specifically on the connection between friendship and well-being. Friendship is a voluntary social relationship between people characterized by mutual concern, trust, and support. Friends tend to spend time with each other, enjoy each other's company, and know personal facts about one another. Friendship can promote emotional support, a sense of belonging, self-esteem, practical guidance, and reduced stress. Different forms of friendship can influence well-being differently. A central aspect is the strength of the connection, distinguishing close friends from distant ones. Strength is determined by factors such as time spent together, trust, emotional intensity, and readiness to support each other in difficult times. The number of friends a person has is another relevant factor, and having many friends is usually beneficial. However, if a person already has numerous friends, making even more friends may not significantly impact their well-being.
=== Extraction and purification === In October 1920, Canadian Frederick Banting concluded that the digestive secretions that Minkowski had originally studied were breaking down the islet secretion, thereby making it impossible to extract successfully. A surgeon by training, Banting knew that blockages of the pancreatic duct would lead most of the pancreas to atrophy, while leaving the islets of Langerhans intact. He reasoned that a relatively pure extract could be made from the islets once most of the rest of the pancreas was gone. He jotted a note to himself: "Ligate pancreatic ducts of dog. Keep dogs alive till acini degenerate leaving Islets. Try to isolate the internal secretion of these + relieve glycosurea[sic]."
==== Phosphodiesterase PDE5 inhibitors ==== Avanafil (Razatus; Spedra; Stendra; TA-1790; Zepeed) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [114] Lodenafil (CRIS-031; Helleva) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [115] Mirodenafil (Aibishi; Bravonto; Mvix; SK-3530) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [116] Sildenafil (Revatio; Revatio IV; UK-92480; Viagra) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [117] Sildenafil chewable tablets (Nurigra) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [118] Sildenafil orally soluble film (sildenafil ODF; SPO-1101; Vultis) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [119] Sildenafil orally soluble film (orodispersible sildenafil; Please; sildenafil oral dissolving film; sildenafil orally-disintegrating film; sildenafil OSF) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [120] Sildenafil oral spray (ASP-001; ASP-002; Bandol; Hezkue) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [121] Sildenafil oro-dispersible tablets (Erecta; FACSID-50) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [122] Simmerafil (Onvita; Onweida; semenafil; TPN-171; TPN-171-H) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [123] Tadalafil (Adcirca; Cialis; GF-196960; IC-351; LY-450190; Zalutia) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [124] Tadalafil oral disintegrating film (SPO-1102; Vulteum; tadalafil ODF) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [125] Tadalafil oral film (OGOOD) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [126] Udenafil (DA-8159; Jurvigo; ME-3113; MZ101; Udzire; WC-3043; WC-3055; Zydena) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [127] Vardenafil (BAY-389456; Levitra; Nuviva; Staxyn; vardenafil ODT; vardenafil orodispersible tablet; Vivanza) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [128]
Sources: en.wikipedia.org
Insulin receptor substrates (IRS) are important ligands in the insulin response of human cells. IRS-1, for example, is an IRS protein that contains a phosphotyrosine binding-domain (PTB-domain). In addition, the insulin receptor contains a NPXY motif. The PTB-domain binds the NPXY sequence. Thus, the insulin receptor binds IRS.
== External links == Wladimir Lyra Archived 12 November 2023 at the Wayback Machine, "Living in a comet: How to build a Dyson treehouse". Las Cruces Sun-News, March 2020. Dyson Tree – Innovative Technologies from Science Fiction for Space Application.
Food chains are often used in ecological modeling (such as a three-species food chain). They are simplified abstractions of real food webs, but complex in their dynamics and mathematical implications. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web. The mean chain length of an entire web is the arithmetic average of the lengths of all chains in the food web. The food chain is an energy source diagram. The food chain begins with a producer, which is eaten by a primary consumer. The primary consumer may be eaten by a secondary consumer, which in turn may be consumed by a tertiary consumer. The tertiary consumers may sometimes become prey to the top predators known as the quaternary consumers. For example, a food chain might start with a green plant as the producer, which is eaten by a snail, the primary consumer. The snail might then be the prey of a secondary consumer such as a frog, which itself may be eaten by a tertiary consumer such as a snake which in turn may be consumed by an eagle. This simple view of a food chain with fixed trophic levels within a species: species A is eaten by species B, B is eaten by C, ... is often contrasted by the real situation in which the juveniles of a species belong to a lower trophic level than the adults, a situation more often seen in aquatic and amphibious environments, e.g., in insects and fishes. This complexity was denominated metaphoetesis by G. E. Hutchinson, 1959.
Normally in humans only one follicle becomes dominant and survives to grow to 18–30 mm in size and ovulate, the remaining follicles in the cohort undergo atresia. The sharp increase in estradiol production by the dominant follicle (possibly along with a decrease in gonadotrophin surge-attenuating factor) cause a positive effect on the hypothalamus and pituitary and rapid GnRH pulses occur and an LH surge results. The increase in serum estradiol levels causes a decrease in FSH production by inhibiting GnRH production in the hypothalamus. The decrease in serum FSH level causes the smaller follicles in the current cohort to undergo atresia as they lack sufficient sensitivity to FSH to survive. Occasionally two follicles reach the 10 mm stage at the same time by chance and as both are equally sensitive to FSH both survive and grow in the low FSH environment and thus two ovulations can occur in one cycle possibly leading to non-identical (dizygotic) twins.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
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.