epithalamin raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-28. Anything still debated is marked as such rather than presented as settled.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
Epitalon is a synthetic tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by HPLC area | Higher grades are also offered |
| Primary analytical method | Reversed-phase HPLC, UV detection | Frequently paired with mass spectrometry |
| Confirmatory technique | Electrospray mass spectrometry | Observed mass compared with theory |
| Storage temperature | Minus 20 degrees Celsius, dry powder | Sealed, desiccated, protected from light |
| Solution handling | Prepare fresh before use | Hydrolysis proceeds in aqueous media |
Regulatory status varies by country and is not harmonized. Epitalon is not an approved drug in major Western jurisdictions. In some countries it is sold as a research chemical, and in others it has appeared in products marketed for other categories. This inconsistent status means that purity, labeling accuracy, and documentation differ widely between suppliers, and verification of identity and purity through independent analysis is the usual way buyers assess a given lot.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
== Publications == The first edition was published by the WHO on 15 May 2018, and complements the WHO Model List of Essential Medicines (EML), which was published more than 40 years earlier. More than 150 countries have adapted the WHO Model List of Essential Medicines. A second edition was published in July 2019, and a third in 2020.
Thermospray ionization is a form of atmospheric pressure ionization in mass spectrometry. It transfers ions from the liquid phase to the gas phase for analysis. It is particularly useful in liquid chromatography-mass spectrometry.
=== Effect on diet and lifestyle === The refrigerator allows households to keep food fresh for longer than before. The most notable improvement is for meat and other highly perishable wares, which previously needed to be preserved or otherwise processed for long-term storage and transport. This change in the supply chains of food products led to a marked increase in the quality of food in areas where refrigeration was being used. Additionally, the increased freshness and shelf life of food caused by the advent of refrigeration in addition to growing global communication methods has resulted in an increase in cultural exchange through food products from different regions of the world. There have also been claims that this increase in the quality of food is responsible for an increase in the height of United States citizens around the early 1900s. Refrigeration has also contributed to a decrease in the quality of food in some regions. By allowing, in part, for the phenomenon of globalization in the food sector, refrigeration has made the creation and transportation of ultra-processed foods and convenience foods inexpensive, leading to their prevalence, especially in lower-income regions. These regions of lessened access to higher quality foods are referred to as food deserts. Freezers allow people to buy food in bulk and eat it at leisure, and bulk purchases may save money. Ice cream, a popular commodity of the 20th century, could previously only be obtained by traveling to where the product was made and eating it on the spot. Now it is a common food item.
Flavor ingredients used in instant ramen noodle soup include dried vegetables and meats, salt, MSG, onion, garlic, yeast extract, hydrolyzed vegetable protein, essential oil extracts and natural or synthetic flavor compounds. Essential oils derived from onion, garlic and clove are sometimes used as flavorings for instant ramen soup, and may be manufactured using expeller pressing or solvent extraction and distillation. Sophisticated methods exist that create flavor compounds, or complex flavors, for the flavoring of instant ramen noodle soups. A desired flavor is analyzed using techniques such as gas chromatography utilized with mass spectrometry and olfactometry, so that it can be reconstituted through blending more common ingredients.
Sources: en.wikipedia.org
A gonadotropin release inhibitor is a substance that reduces the secretion of gonadotropins by the anterior pituitary gland. In particular, this means that it reduces the amount of luteinizing hormone (LH) and/or follicle stimulating hormone (FSH) released. Gonadotropins are hormones that signal to the gonads and play a crucial role in the process of gonadal development and function in vertebrates. In birds and mammals, luteinizing hormone (LH) regulates sex steroid production as well as ovulation, whereas follicle stimulating hormone (FSH) promotes spermatogenesis and ovarian follicle maturation. Their release is primarily induced by gonadotropin-releasing hormone (GnRH) (a hypothalamic decapeptide isolated from the mammalian brain in the early 1970s), however several other GnRHs have also been identified in the brains of other vertebrates. Some neurochemicals and peripheral hormones (e.g.gamma-aminobutyric acid (GABA), opiates, gonadal sex steroids, inhibin) can modulate gonadotropin release, but a more specific hypothalamic inhibitory hormone was only identified more recently. In birds, a peptide Gonadotropin-inhibitory hormone was found to suppress gonadotropin release, and later homologous neuropeptides were discovered in mammals, coded by the gene NPVF.
The size of aquasomes ranges from 60 to 300 nanometers, hence their characterization as a nanoparticle drug carrier. The nanoscale of aquasomes gives them a high surface area to volume ratio. The smaller the core, the higher the surface area to volume ratio, which increases the drug loading capacity of the aquasome. Aquasomes possess water-like properties due to the presence of the carbohydrate coating, enabling them to protect and preserve fragile biological molecules. The size of aquasome particles increases as a function of the ratio between the concentration of the core to the coat due to the availability of free surface core particles for the coating material. The self-assembly process of aquasomes into their tri-layer structure is achieved by non-covalent and ionic bonds, along with physicochemical properties of their components. Calcium phosphate nanoparticles are formed before the carbohydrate coat is adsorbed onto the surface of the core through electrostatic interactions. Layers are then added to the structure to achieve desired size, while crosslinked polymers aid in further stabilization. The sonication process during the reaction of disodium hydrogen phosphate and calcium chloride to prepare calcium phosphate impacts the self-assembly process of aquasomes by increasing surface free energy of the core prepared. This assembly process allows the design of aquasomes for specific drug delivery applications. The structure of aquasomes can contribute to controlled drug release, drug stability, and intracellular targeting of the drug.
== Metabonomics == Metabonomics is defined as "the quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modification". The word origin is from the Greek μεταβολή meaning change and nomos meaning a rule set or set of laws. This approach was pioneered by Jeremy Nicholson at Murdoch University and has been used in toxicology, disease diagnosis and a number of other fields. Historically, the metabonomics approach was one of the first methods to apply the scope of systems biology to studies of metabolism. There has been some disagreement over the exact differences between 'metabolomics' and 'metabonomics'. The difference between the two terms is not related to choice of analytical platform: although metabonomics is more associated with NMR spectroscopy and metabolomics with mass spectrometry-based techniques, this is simply because of usages amongst different groups that have popularized the different terms. While there is still no absolute agreement, there is a growing consensus that 'metabolomics' places a greater emphasis on metabolic profiling at a cellular or organ level and is primarily concerned with normal endogenous metabolism. 'Metabonomics' extends metabolic profiling to include information about perturbations of metabolism caused by environmental factors (including diet and toxins), disease processes, and the involvement of extragenomic influences, such as gut microflora.
Sources: en.wikipedia.org
The corporate office has had a few locations, and previously maintained an office at 2516 Via Tejon in Palos Verdes, then at 2424 Moreton Street in Torrance before settling into Irvine (at 17901 Von Karman Avenue) in 1976.
The two substrates of this enzyme are 14-demethyllanosterol and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are 4,4-dimethyl-5α-cholesta-8,14,24-trien-3β-ol, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 4,4-dimethyl-5alpha-cholesta-8,24-dien-3beta-ol:NADP+ Delta14-oxidoreductase. This enzyme participates in biosynthesis of steroids.
Despite GLaDOS's attempts to dissuade her with lies and threats, Chell proceeds and eventually confronts GLaDOS in a large chamber where her hardware hangs overhead. A sphere falls from GLaDOS and Chell drops it in an incinerator. GLaDOS reveals that the sphere was the morality core of her conscience, one of multiple personality cores that Aperture Science employees installed after she flooded the center with neurotoxin gas; with the core removed, she can access the neurotoxin emitters again. A six-minute countdown starts as Chell dislodges and incinerates more of GLaDOS' personality cores, while GLaDOS mocks and attacks her. After Chell destroys the last personality core, a malfunction tears the room apart and transports everything to the surface. Chell lies outside the facility's gates amid the remains of GLaDOS, and is promptly dragged away by an unseen robotic entity. The final scene, viewed within the bowels of the facility, shows a candlelit Black Forest cake, and a Weighted Companion Cube, surrounded by shelves containing dozens of inactive personality cores. The cores begin to light up, before a robotic arm descends and extinguishes the candle on the cake, casting the room into darkness. Over the credits, GLaDOS delivers a concluding report through the song "Still Alive", declaring the experiment to be a success.
== Structure == Erythroferrone in humans is transcribed as a precursor of 354 amino acids, with a signal peptide of 28 amino acids. The mouse gene encodes a 340 amino acid protein which is 71% identical. Homology is greater at the C-terminal where there is a TNF-alpha-like domain. As a member of the C1q/TNF-Related Protein (CTRP) family, erythroferrone has a 4-domain structure with a unique N-terminus. The two larger domains are connected by a short, proline-rich, collagenous linker that is thought to promote protein multimerization. Erythroferrone is predicted to contain two PCSK3/furin recognition sites. The protein hormone weighs approximately 35-40 kDa.
Sources: en.wikipedia.org
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.
The dry powder is commonly kept at minus twenty degrees Celsius, desiccated and away from light. Solutions are generally prepared fresh because they break down faster than the solid form.
Tandem mass spectrometry or enzymatic peptide mapping can establish residue order. A single intact mass value indicates composition and molecular weight but not always the precise arrangement of residues.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.