This is a working overview of Pro-Gly-Pro, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-28 and is reviewed periodically as new material appears.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
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.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
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.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
Pharmacology can be applied within clinical sciences. Clinical pharmacology is the application of pharmacological methods and principles in the study of drugs in humans. An example of this is posology, which is the study of the dosage of medicines. Pharmacology is closely related to toxicology. Both pharmacology and toxicology are scientific disciplines that focus on understanding the properties and actions of chemicals. However, pharmacology emphasizes the therapeutic effects of chemicals, usually drugs or compounds that could become drugs, whereas toxicology is the study of chemical's adverse effects and risk assessment. Pharmacological knowledge is used to advise pharmacotherapy in medicine and pharmacy.
One such design has a curved electrostatic path so that the more energetic ions are forced round the outer part of the bend. Another such design incorporates an electrostatic mirror in which the more energetic ions penetrate more deeply before reflection. In both designs, the faster ions have a longer flight path to offset their increased velocity, and all ions of the same mass arrive at the detector simultaneously.
== History == The company was founded in 1929 by Dharampal Sugandhi in Chandni Chowk, Delhi, as a perfumery business producing incense sticks, rose water, and tobacco products. In 1958, Satyapal Sugandhi introduced the BABA tobacco brand. During the 1980s, the group diversified into packaged foods with the launch of Catch Salt & Pepper (1987), followed by Catch Natural Spring Water in 1999. The group's subsequent launches included confectionery products under brands such as Rajnigandha, Pass Pass, and Pulse Candy. In 2019, the DS Group acquired an 11–18% stake in the Switzerland-based Lalique Group . In 2023, it introduced the Swiss chocolate brand Läderach to India and acquired the Indian confectionery brand LuvIt.
Soft and fluffy tempeh made from soy pulp or tofu dregs. Tempe gembus usually can be found in traditional markets of Java, at a price lower than that of common soybean tempeh. It is made into a variety of dishes; for example it can be battered and/or fried, used in sayur lodeh, or tempe bacem. Tempe gembus is known by different names across Java; for example as tahu cokol or tahu susur in Temanggung.
However, some in the Japanese archaeological community remain skeptical about the presence of cattle in Japan during the Yayoi period, and there is a persistent view that they were brought to Japan from the Korean peninsula by the toraijin, a group of people who came to Japan in the mid-5th century during the Kofun period. At the Nango-Ōhigashi site in Gose City, Nara Prefecture, excavations revealed cow bones believed to date back to the 5th century. At the Funamiya Kofun Tumulus (late 5th century) in Asago City, Hyōgo Prefecture, pieces of a cow-shaped haniwa (clay figurine), believed to be the oldest in Japan, have been excavated. In addition, a cow-shaped haniwa was excavated from the Hashida No. 1 Tumulus in Tawaramoto Town, Shiki-gun, Nara Prefecture in the first half of the 6th century, and was designated as an Important Cultural Property of Japan in 1958. On the other hand, recent genetic studies have shown that Wagyu and Korean cattle (Hanwoo and others) differ greatly in their genetic information. Livestock cattle are divided into two major lineages: northern lineage cattle (Bos taurus) and Indian lineage cattle (Bos indicus), and both Wagyu and Korean cattle belong to the northern lineage and do not contain Indian lineage such as Zebu cattle. However, in terms of mitochondrial DNA haplogroups, haplogroup T4 (East Asian type) is predominant in the Wagyu (Japanese Black) at about 65%, while haplogroup T3 (European type) is predominant in Korean cattle at 66–83%.
Sources: en.wikipedia.org
== Structure == LH is a heterodimeric glycoprotein. Each monomeric unit is a glycoprotein molecule; one alpha and one beta subunit make the full, functional protein. Its structure is similar to that of the other glycoprotein hormones, follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), and human chorionic gonadotropin (hCG). The protein dimer contains 2 glycopeptidic subunits (labeled alpha- and beta- subunits) that are non-covalently associated:
== History == The FDA's approval of sildenafil in 1998 was a ground-breaking commercial event for the treatment of ED, with sales exceeding US$1 billion. Subsequently, the FDA approved both vardenafil and tadalafil in 2003. It initially was developed by the biotechnology company ICOS, and then again developed and marketed worldwide by Lilly ICOS, LLC, the joint venture of ICOS Corporation and Eli Lilly and Company. Tadalafil was approved in 2009 in the United States for the treatment of pulmonary arterial hypertension and is under regulatory review in other regions for this condition. In late November 2008, Eli Lilly sold the exclusive rights to commercialize tadalafil for pulmonary arterial hypertension in the United States to United Therapeutics for an upfront payment of $150 million. Tadalafil was discovered by Glaxo Wellcome (now GlaxoSmithKline) under a partnership between Glaxo and ICOS to develop new drugs that began in August 1991. In 1993, the Bothell, Washington, biotechnology company ICOS Corporation began studying compound IC351, a phosphodiesterase type 5 (PDE5) enzyme inhibitor. In 1994, Pfizer scientists discovered that sildenafil, which also inhibits the PDE5 enzyme, caused penile erection in males participating in a clinical study of a heart medicine. Although ICOS scientists were not testing compound IC351 for treating ED, they recognized its potential usefulness for treating that disorder. Soon, in 1994, ICOS received a patent for compound IC351 (structurally unlike sildenafil and vardenafil), and Phase 1 clinical trials began in 1995.
The two substrates of this enzyme are (3S,4R)-3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are protocatechuic acid, carbon dioxide, reduced NADH and a proton. This enzyme is a part of the terephthalate degradation pathway in bacteria.
The most important transport way in Schleswig-Holstein is Kiel Canal, which connect Brunsbüttel on North Sea with Kiel on Baltic Sea. Total cargo of ships reach peaks in 2007 and 2012, after that it continuous decline with 73.8 million tonnes in 2020.
== Charity == Through its fundraiser "Drink One for Dane", Dutch Bros Coffee donates to the Muscular Dystrophy Association. Its other annual charitable initiatives include Dutch Luv, which benefits local food banks, and Buck for Kids, which supports local youth organizations, including chapters of the Boys & Girls Clubs of America.
Sources: en.wikipedia.org
=== Short-term effects === The EMCDDA reported mephedrone can cause various unintended side effects including dilated pupils, poor concentration, teeth grinding, problems focusing visually, poor short-term memory, hallucinations, delusions, and erratic behaviour. They noted the most severe effects appear anecdotally to be linked with high doses or prolonged use, and the effects may be due to users taking other intoxicants at the same time. Other effects users in internet forums have noted include changes in body temperature, increased heart rate, breathing difficulties, loss of appetite, increased sweating, discolouration of extremities, anxiety, paranoia and depression. When snorted, it can also cause nose bleeds and nose burns. A survey conducted by the UK National Addiction Centre found 67% of mephedrone users experienced sweating, 51% suffered from headaches, 43% from heart palpitations, 27% from nausea and 15% from cold or blue fingers, indicative of vasoconstriction occurring. Doctors at Guy's Hospital in London reported that of 15 patients they treated after taking mephedrone in 2009, 53% were agitated, 40% had increased heart rates, 20% had systolic hypertension and 20% had seizures; three required treatment with benzodiazepines, predominantly to control their agitation. They reported none of their patients suffered from cold or blue peripheries, contrary to other reports.
When exposed to neutron bombardment 237Np can capture a neutron, undergo beta decay, and become 238Pu, this product being useful as a thermal energy source in a radioisotope thermoelectric generator (RTG or RITEG) for the production of electricity and heat. The first type of thermoelectric generator SNAP (Systems for Nuclear Auxiliary Power) was developed and used by NASA in the 1960's and during the Apollo missions to power the instruments left on the Moon surface by the astronauts. Thermoelectric generators were also embarked on board of deep space probes such as for the Pioneer 10 and 11 missions, the Voyager program, the Cassini–Huygens mission, and New Horizons. They also deliver electrical and thermal power to the Mars Science Laboratory (Curiosity rover) and Mars 2020 mission (Perseverance rover) both exploring the cold surface of Mars. Curiosity and Perseverance rovers are both equipped with the last version of multi-mission RTG, a more efficient and standardized system dubbed MMRTG. These applications are economically practical where photovoltaic power sources are weak or inconsistent due to probes being too far from the sun or rovers facing climate events that may obstruct sunlight for long periods (like Martian dust storms). Space probes and rovers also make use of the heat output of the generator to keep their instruments and internals warm.
== Interactions == LRP5 has been shown to interact with AXIN1. Canonical WNT signals are transduced through Frizzled receptor and LRP5/LRP6 coreceptor to downregulate GSK3beta (GSK3B) activity not depending on Ser-9 phosphorylation. Reduction of canonical Wnt signals upon depletion of LRP5 and LRP6 results in p120-catenin degradation.
== Women in Cinema Collective == In May 2017, following the sexual assault of a prominent Malayalam film actress in Kochi, Kallingal was among a group of women film professionals who petitioned the Chief Minister of Kerala and subsequently co-founded the Women in Cinema Collective (WCC). The WCC was formally registered as a society on 1 November 2017. The WCC's petition to the government resulted in the formation of the Justice Hema Committee in 2018, tasked with studying the conditions faced by women in the Malayalam film industry. The committee submitted its report in December 2019; it was made public in August 2024 and documented systemic issues including gender-based discrimination, inadequate workplace safety, and the prevalence of power-based exploitation. As a member of the Association of Malayalam Movie Artists (AMMA), Kallingal resigned in protest when the association reinstated a member accused in the 2017 assault case while the matter was still under judicial consideration. She was one of three WCC members — along with Geethu Mohandas and Remya Nambissan — to resign alongside the survivor herself. Kallingal has spoken publicly about the personal and professional costs of the collective's advocacy. "We knew it would be tough, but we never imagined it would cost us personal relationships, careers and expose us to such intense social trolling," she told The Federal in 2024.
=== Synthesis === Adrenochrome is readily synthesized from commercially available reagents: chloroacetic acid and catechol react in the presence of phosphoryl chloride to yield chloroacetylcatechol. After purification, chloroacetylcatechol is reacted with aqueous methylamine and treated with hydrochloric acid, yielding adrenalone hydrochloride. This is then hydrogenated to racemic adrenaline. Finally, adrenaline is oxidized to adrenochrome by an appropriate oxidizing agent such as silver oxide.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
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.