This is a working overview of Regulatory peptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-02. Anything still debated is marked as such rather than presented as settled.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
| 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 |
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.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
=== Neuron survival === Binding interaction between NGF and the TrkA receptor facilitates receptor dimerization and tyrosine residue phosphorylation of the cytoplasmic tail by adjacent Trk receptors. Trk receptor phosphorylation sites operate as Shc adaptor protein docking sites, which undergo phosphorylation by the TrkA receptor Once the cytoplasmic adaptor protein (Shc) is phosphorylated by the receptor cytoplasmic tail, cell survival is initiated through several intracellular pathways. One major pathway leads to the activation of the serine/threonine kinase, Akt. This pathway begins with the Trk receptor complex-recruitment of a second adaptor protein called growth factor-receptor bound protein-2 (Grb2) along with a docking protein called Grb2-associated Binder-1 (GAB1). Subsequently, phosphatidylinositol-3 kinase (PI3K) is activated, resulting in Akt kinase activation. Study results have shown that blocking PI3K or Akt activity results in death of sympathetic neurons in culture, regardless of NGF presence. However, if either kinase is constitutively active, neurons survive even without NGF. A second pathway contributing to cell survival occurs through activation of the mitogen-activated protein kinase (MAPK) kinase. In this pathway, recruitment of a guanine nucleotide exchange factor by the adaptor and docking proteins leads to activation of a membrane-associated G-protein known as Ras. The guanine nucleotide exchange factor mediates Ras activation through the GDP-GTP exchange process.
==== Antifungals ==== Regular use of an over-the-counter or prescription antifungal shampoo or cream is a common treatment. The topical antifungal medications ketoconazole and ciclopirox have the best evidence. Ketoconazole should be used twice per week. Shampoo or soap containing zinc pyrithione, selenium disulfide, or piroctone olamine is also used. Products containing zinc pyrithione have been banned in the European Union since 2021 due to concerns over environmental toxicity alongside the presence of suitable alternatives. These options are often used daily and may also be used in conjunction with a ketoconazole shampoo regimen on alternate days. It is unclear if other antifungals are equally effective, as this has not been sufficiently studied. Antifungals that have been studied and found to be effective in the treatment of seborrhoeic dermatitis include ketoconazole, fluconazole, miconazole, bifonazole, sertaconazole, clotrimazole, flutrimazole, ciclopirox, terbinafine, butenafine, selenium disulfide, piroctone olamine and lithium salts such as lithium gluconate and lithium succinate. Topical climbazole appears to have little effectiveness in the treatment of seborrhoeic dermatitis. Systemic therapy with oral antifungals including itraconazole, fluconazole, ketoconazole is effective. Adverse side effects have been documented for fluconazole and ketoconazole, with the latter not recommended for use, while itraconazole, with its good safety profile, is the most commonly prescribed.
August 19–September 1: The Viet Minh seizes control of Hanoi and much of the former Empire of Vietnam after the surrender of Japan, proclaiming the Democratic Republic of Vietnam and initiating civil conflicts. September 2: Surrender of Japan - The Empire of Japan surrenders unconditionally to the United States, officially ending World War II. General Douglas MacArthur presides over the occupation of Japan, and freezes out Russian and other allied representatives(V-J day). September 5: Igor Gouzenko, a Soviet agent working in the Soviet embassy in Canada, defects and provides proof to the Royal Canadian Mounted Police of a Soviet spy ring operating in Canada and the U.S. The revelations help change perceptions of the Soviet Union from an ally to a foe. October 25: Taiwan is transferred to the Republic of China from Japan. Initially the Chinese public was supportive of the transfer but later becomes less so as the newly appointed governor, General Chen Yi gains a reputation for being corrupt and mismanaging the island. Economic problems also occur as the governor extends the scope of the government monopoly over Taiwan's resources in order to sell these goods to the mainland to help fight the Communist forces. The conditions on the island later contribute to the February 28 incident. November: Iran crisis of 1946 - Stalin refuses to relinquish Soviet-occupied territory in Iran, beginning the Iran Crisis. Two short-lived pro-Soviet states, the Azerbaijan People's Government and the Republic of Mahabad, are formed. November 20: The Nuremberg trials begin.
Green garlic is indicative of harvesting that has taken place before the cloves have ripened, 'soft' garlic is the term given to a harvested garlic that is fully developed, while damaged garlic, with a caramelized appearance inside, has been harvested too late and a result of frost. When the leaves turn yellow in color, harvesting may be initiated.
Sources: en.wikipedia.org
==== Mammalian studies ==== Studies conducted in rats have indicated that their degree of sexual arousal is sensitive to reductions in testosterone. When testosterone-deprived rats were given medium levels of testosterone, their sexual behaviors (copulation, partner preference, etc.) resumed, but not when given low amounts of the same hormone. Therefore, these mammals may provide a model for studying clinical populations among humans with sexual arousal deficits such as hypoactive sexual desire disorder. Every mammalian species examined demonstrated a marked increase in a male's testosterone level upon encountering a novel female. The reflexive testosterone increases in male mice is related to the male's initial level of sexual arousal. In non-human primates, it may be that testosterone in puberty stimulates sexual arousal, which allows the primate to increasingly seek out sexual experiences with females and thus creates a sexual preference for females. Some research has also indicated that if testosterone is eliminated in an adult male human or other adult male primate's system, its sexual motivation decreases, but there is no corresponding decrease in ability to engage in sexual activity (mounting, ejaculating, etc.). In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.
=== Recreational use === Recreational use of bupropion is uncommon. While bupropion demonstrates some potential for recreational use, this potential is less than that of other commonly used stimulants, being limited by features of its pharmacology. Case reports describe the recreational use of bupropion as producing a "high" similar to cocaine or amphetamine usage but with less intensity. There have been some anecdotal and case-study reports of bupropion abuse, but the bulk of evidence indicates that the subjective effects of bupropion when taken orally are markedly different from those of addictive stimulants such as cocaine or amphetamine. However, bupropion, by non-conventional routes of administration like injection or insufflation, has been reported to be used recreationally in the United States and Canada, notably in prisons. Bupropion has also been encountered as a novel designer drug or adulterant in the United States and Europe.
Thus, the two substrates of this enzyme are isopregnanolone and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are 5α-dihydroprogesterone, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 3β-hydroxy-5α-steroid:NADP+ 3-oxidoreductase.
Sources: en.wikipedia.org
Important branches today are the tourism industry with TUI AG in Hanover, one of Europe's largest travel companies, as well as trade and telecommunications. Hanover is one of Germany's main hubs for insurance and financial-services companies, for example Talanx and Hannover Re. In October 2018, the Lower Saxony unemployment rate stood at 5.0% and was marginally higher than the national average.
However, the amount of radium produced globally has always been small in comparison to other elements, and by the 2010s, annual production of radium, mainly via extraction from spent nuclear fuel, was less than 100 grams. In nature, radium is found in uranium ores in quantities as small as a seventh of a gram per ton of uraninite, and in thorium ores in trace amounts. Radium is not necessary for living organisms, and its radioactivity and chemical reactivity make adverse health effects likely when it is incorporated into biochemical processes because of its chemical mimicry of calcium, due to them both being group 2 elements. As of 2018, other than in nuclear medicine, radium has no commercial applications. Formerly, from the 1910s to the 1970s, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative power. In nearly all of its applications, radium has been replaced with less dangerous radioisotopes, with one of its few remaining non-medical uses being the production of actinium in nuclear reactors.
Crustacean hyperglycaemic hormone (CHH). CHH is primarily involved in blood sugar regulation, but also plays a role in the control of moulting and reproduction. Moult-inhibiting hormone (MIH). MIH inhibits Y-organs where moulting hormone (ecdysteroid) is secreted. A moulting cycle is initiated when MIH secretion diminishes or stops. Gonad-inhibiting hormone (GIH), also known as vitellogenesis-inhibiting hormone (VIH) because of its role in inhibiting vitellogenesis in female animals. Mandibular organ-inhibiting hormone (MOIH). MOIH represses the synthesis of methyl farnesoate, the precursor of insect juvenile hormone III in the mandibular organ. Ion transport peptide (ITP) from locust. ITP stimulates salt and water reabsorption and inhibits acid secretion in the ileum of the locust. Caenorhabditis elegans uncharacterised protein ZC168.2. These neurohormones are peptides of 70 to 80 amino acid residues which are processed from larger precursors. They contain six conserved cysteines that are involved in disulfide bonds.
=== Reporting === As per Art. 323, it will be the duty of the Union Commission to annually present a report to the President on the work done by the commission. On receipt of such report, the president shall present a copy before each House of Parliament, together with a memorandum, if any, explaining the reasons why he did not accept the advice of the commission. The president may also remove the chairman or other member of the commission if he/she/they:
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.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.