The short version of Selank fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-03-11 and is reviewed periodically as new material appears.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
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 |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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 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 with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
== History == Efficacy was evaluated in TROPION-Breast01 (NCT05104866), a multicenter, open-label, randomized trial. Participants must have experienced disease progression, been deemed unsuitable for further endocrine therapy, and have received one or two lines of prior chemotherapy for unresectable or metastatic disease. Participants were excluded for a history of ILD/pneumonitis requiring steroids, ongoing ILD/pneumonitis, clinically active brain metastases, or clinically significant corneal disease. Participants also were excluded for ECOG performance status >1. Randomization was stratified by previous lines of chemotherapy, prior CDK4/6 inhibitor treatment, and geographical region. A total of 732 participants were randomized (1:1) to datopotamab deruxtecan (n=365) or investigator's choice of chemotherapy (n=367); eribulin (60%), capecitabine (21%), vinorelbine (10%), or gemcitabine (9%). Efficacy was evaluated in a pooled subgroup of 114 participants with locally advanced or metastatic epidermal growth factor receptor-mutated non-small cell lung cancer who had received prior treatment with an epidermal growth factor receptor-directed therapy and platinum-based chemotherapy and received datopotamab deruxtecan at the recommended dose across two clinical trials: TROPION-Lung05 and TROPION-Lung01. TROPION-Lung05 (NCT04484142) was a multi-center, single-arm trial, while TROPION-Lung01 (NCT04656652) was a multi-center, open-label, randomized controlled trial.
== Testing for catecholamines == Catecholamines are secreted by cells in tissues of different systems of the human body, mostly by the nervous and the endocrine systems. The adrenal glands secrete certain catecholamines into the blood when the person perceives a threat and prepares for a fight-or-flight response. However, acute or chronic excess of circulating catecholamines can potentially increase blood pressure and heart rate to very high levels and eventually provoke dangerous effects. Tests for fractionated plasma free metanephrines or the urine metanephrines are used to confirm or exclude certain diseases when the doctor identifies signs of hypertension and tachycardia that don't adequately respond to treatment. Each of the tests measure the amount of adrenaline and noradrenaline metabolites, respectively called metanephrine and normetanephrine. Blood tests are also done to analyze the amount of catecholamines present in the body. Catecholamine tests are done to identify rare tumors at the adrenal gland or in the nervous system. Catecholamine tests provide information relative to tumors such as: pheochromocytoma, paraganglioma, and neuroblastoma.
At the beginning of the war, the U.S. was neutral in the conflict because of its opposition to European colonialism, because the Việt Minh had recently been U.S. allies, and because, in the context of the Cold War, most of its attention was focused on Europe where Winston Churchill argued an "Iron Curtain" had fallen. The 1949 victory of Mao Zedong's Chinese Communist Party in the Chinese Civil War, the recognition of the DRV by the USSR and the newly formed People's Republic of China in January 1950, which prompted the US and the UK to recognize the State of Vietnam in response, and the signing of the Sino-Soviet Treaty of Friendship shortly after in February, shifted the US stance on the matter, and the war came to be viewed as another front in the anticommunist struggle. Indochina, and Southeast Asia more broadly, was declared vital by the U.S. government, and the containment of communism at the southern Chinese border, and, later, Korea, became one of the priorities of American foreign policy as it was believed that the fall of Indochina to communist hands would lead to the loss of other nations in the region. At this time, communism was seen as a uniform bloc, dominated by the Soviet Union. It was feared in Washington that if Ho were to win the war, he would establish a state politically aligned with Moscow, with the Soviets ultimately controlling Vietnamese affairs. This prospect spurred the U.S. to support France in their war effort, primarily through the Mutual Defense Assistance Act. In May 1950, after Chinese communist forces occupied Hainan island, U.S.
=== Protein modification === A classic way to crystalize is by adding a small amount of protease to the droplet, as digestion may yield a more crystallizable fragment by removing unstructured regions. Chemical modification can be used to improve crystallization. The most commonly used is reductive methylation, which changes surface lysines in a way that usually reduces entropy.
Sources: en.wikipedia.org
TsrM in thiostrepton biosynthesis PoyD and PoyC in polytheonamide biosynthesis TbtI in thiomuracin biosynthesis NosN in nosiheptide biosynthesis EpeE (previously called YydG) in epipeptide biosynthesis MoaA in molybdopterin biosynthesis PqqE in pyrroloquinoline quinone biosynthesis TunB in tunicamycin biosynthesis OxsB in oxetanocin biosynthesis BchE in anaerobic bacteriochlorophyll biosynthesis F0 synthases in F420 cofactor biosynthesis MqnE and MqnC in menaquinone biosynthesis QhpD in post-translational processing of quinohemoprotein amine dehydrogenase RumMC2 in ruminococcin C biosynthesis
== Ion-exchange chromatography == DEAE-C is a weak anion exchanger. This exchange is utilized to separate proteins that have faintly differing charges. Like all anion exchangers, the resin carries a positive charge that interacts favorably with negative charges. The positive charge of DEAE cellulose is due to a protonated amine group. To ensure that the resin is protonated and positively charged, the chromatography should be performed at least 2 pH units below the pKa of the amine group, 10. The strength of the bond between the resin and protein is highly dependent on the pH range in the column and the pI of the protein of interest. The resin is a weak exchanger because it is only partially ionized over most pH values, and an efficient separation with DEAE-C chromatography requires a specific, narrow pH range. Cellulose, dextran, agarose, and other insoluble complexes are unaffected because they compose inert matrices, hence why they are so often derivatized with strong and weak cation and anion exchangers in chromatography. DEAE-C beads have diethylaminoethyl chains covalently bound to oxygen atoms on the D-glucose subunits of cellulose.
==== Quantities required ==== A rule of thumb for dry ice bath branding states that twenty pounds (9.1 kg) of dry ice and three US gallons (11 L) of 99% alcohol are sufficient to freeze-brand one hundred head of cattle inside a three to four-hour period. An entire day of freeze branding may consume 50–75 pounds (23–34 kilograms) of dry ice and six to nine US gallons (23 to 34 L) of ethanol. The dry ice should be broken up into egg-sized pieces, placed in a styrofoam container or styrofoam-insulated metal cooler and covered with at least three inches (7.6 cm) of alcohol. Many consumer coolers are made from plastics that become exceptionally brittle at cryogenic temperatures. This is a safety concern if heavy metal brands are frequently returned to coolant baths because 99% alcohol is extremely flammable. Insulated aluminum containers are preferred.
An insulinoma is a tumour of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumour. Most insulinomas are benign in that they grow exclusively at their origin within the pancreas, but a minority metastasize. Insulinomas are one of the functional pancreatic neuroendocrine tumour (PNET) group ("functional" because it increases production of insulin). In the Medical Subject Headings classification, insulinoma is the only subtype of "islet cell adenoma". Beta cells secrete insulin in response to increases in blood glucose. The resulting increase in insulin acts to lower blood glucose back to normal levels, the point at which further secretion of insulin is stopped. In contrast, the secretion of insulin by insulinomas is rather independent of blood glucose; these tumours continue to secrete insulin, causing blood glucose levels to fall further below normal. As a result, patients present symptoms of low blood glucose (hypoglycemia), which are improved by eating. The diagnosis of an insulinoma is usually made biochemically with low blood glucose, elevated insulin, proinsulin, and C-peptide levels, and confirmed by localizing the tumour with medical imaging or angiography. The definitive treatment is surgery.
Sex differences in hormone levels may induce women to respond differently than men to nicotine. When women undergo cyclic changes or different hormonal transition phases (menopause, pregnancy, adolescence), there are changes in their progesterone levels. Therefore, females have an increased biological vulnerability to nicotine's reinforcing effects compared to males, and progesterone may be used to counter this enhanced vulnerability. This information supports the idea that progesterone can affect behavior. Similar to nicotine, cocaine also increases the release of dopamine in the brain. The neurotransmitter is involved in the reward center and is one of the main neurotransmitters involved with substance abuse and reliance. In a study of cocaine users, it was reported that progesterone reduced craving and the feeling of being stimulated by cocaine. Thus, progesterone was suggested as an agent that decreases cocaine craving by reducing the dopaminergic properties of the drug.
Sources: en.wikipedia.org
==== Egypt ==== Egypt approved Viagra for sale in 2002, but soon afterwards allowed local companies to produce generic versions of the drug, citing the interests of poor people who would not be able to afford Pfizer's price.
The benthic layer is more efficient with low flow of methane, and efficiency decreases as methane flow or the speed of flow increases. Oxygen demand for cold seep ecosystems is much higher than other benthic ecosystems, so if the bottom water does not have enough oxygen, then the efficiency of aerobic microbes in removing methane is reduced. The benthic filter cannot affect methane that is not traveling through the sediment. Methane can bypass the benthic filter if it bubbles to the surface or travels through cracks and fissures in the sediment. These organisms are the only biological sink of methane in the ocean.
The redeeming feature of his trip was a dish of venison, he thought, served with a confit of pear in mulled wine and Savoy cabbage with a red wine and smoked chocolate sauce, but he otherwise felt that the food was "over-worked" and the service "peculiarly amateurish".
The ring destructive pathway consists of the selective cleavage of carbon-carbon bonds with release of small organic sulfides soluble in the surrounding aqueous environment, whereas the sulfur-specific pathways rely on successive sulfur redox reactions to release sulfur either as sulfide or sulfite anions as byproducts. The latter have thus been considered as a very promising pathway to produce sulfur-free compounds with a high calorific content, in particular in the desulfurization of sulfur heterocycles abundant in sour crude oil fractions.
=== Daria Greenock === Daria Greenock (Freya Mavor) is a VP at Pierpoint's CPS desk, and Harper's line manager during her internship. Daria works to foster a poised, professional relationship with Harper, who nonetheless finds herself drawn more to Eric's fiery, cutthroat management style, frequently undercutting Daria in the process. When Harper confides to Daria that Eric locked her in a conference room to berate her for a mistake, Daria tells Sara and the two push Harper to file a formal complaint, getting Eric fired and positioning Daria to become CPS' managing director in his place. Harper is initially allowed to keep the outsize bonus that Eric paid her as long as she keeps it quiet, but Daria later has Harper pay it back after Harper talks about it during a party. On RIF day, Harper accepts a deal to retract her complaint against Eric and get him rehired, leading to Daria's firing. In series 2, Daria is revealed to have joined Goldman Sachs; though she is on maternity leave, she visits the office during a sham interview with Harper, Eric, and Rishi to revel in their humiliation. In series 3, however, Daria agrees to help Harper short Pierpoint alongside Kenny and Jackie, who have also joined Goldman Sachs, out of spite towards their ex-employer.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.