Pineal gland raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
Typical storage for the lyophilized powder is −20 °C or lower, in a sealed container protected from light and moisture. Hygroscopic material should be allowed to equilibrate to room temperature before the vial is opened, which limits condensation on the contents. Working solutions are commonly divided into single-use aliquots and frozen to avoid repeated freeze-thaw cycles. Dilute solutions are more prone to adsorption onto plastic surfaces and to loss during filtration, so procedures that minimize transfers and use low-binding labware are preferable.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Computed for the free acid of Ala-Glu-Asp-Gly |
| Molecular mass | About 390.35 g/mol | Free peptide; salt forms shift the value |
| Appearance | White to off-white solid | Typical of short peptides after freeze-drying |
| Solubility class | Freely soluble in water | Aqueous buffers are also commonly used |
| Common synonyms | Epitalon, epithalone, AEDG | AEDG is the single-letter sequence |
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
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.
The most widely cited claim is that epitalon activates telomerase and thereby extends telomere length. Supporting evidence comes largely from cultured human cells, where treatment was associated with increased telomerase activity and delayed replicative senescence. Telomerase activation is a biologically consequential effect, since the enzyme is largely silenced in most somatic cells. However, the route by which a short peptide would reach and act on the enzyme's regulatory machinery has not been established. Independent replication in human trials is scarce, so the link between cell-culture observations and whole-body aging remains an open question.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
1993/1626) Castle Vale Housing Action Trust (Area and Constitution) Order 1993 (S.I. 1993/1634) Gipsy Encampments (Borough of Surrey Heath) Order 1993 (S.I. 1993/1635) Tower Hamlets Housing Action Trust (Area and Constitution) Order 1993 (S.I. 1993/1636) Value Added Tax (General) (Amendment) (No. 5) Regulations 1993 (S.I. 1993/1639) Reconstitution of the Witham First District Internal Drainage Board Order 1993 (S.I. 1993/1640) Import (Plant Health Fees) (England and Wales) Order 1993 (S.I. 1993/1641) Plant Passport (Plant Health Fees) (England and Wales) Regulations 1993 (S.I. 1993/1642) Environmental Protection (Controls on Injurious Substances) (No. 2) Regulations 1993 (S.I. 1993/1643) Alcan Aluminium UK Ltd. (Rateable Values) (Scotland) Order 1993 (S.I. 1993/1644) Forth Ports plc (Rateable Values) (Scotland) Order 1993 (S.I. 1993/1645) Caledonian MacBrayne Limited (Rateable Values) (Scotland) Order 1993 (S.I. 1993/1646) Tunbridge Wells and Eridge Light Railway Order 1993 (S.I. 1993/1651) Asylum and Immigration Appeals Act 1993 (Commencement and Transitional Provisions) Order 1993 (S.I. 1993/1655) Immigration (Restricted Right of Appeal against Deportation) (Exemption) Order 1993 (S.I. 1993/1656) Immigration (Variation of Leave) (Amendment) Order 1993 (S.I. 1993/1657) Extraction Solvents in Food Regulations 1993 (S.I. 1993/1658) Education (Assisted Places) (Scotland) Amendment Regulations 1993 (S.I. 1993/1659) St Mary's Music School (Aided Places) Amendment Regulations 1993 (S.I. 1993/1660) Asylum Appeals (Procedure) Rules 1993 (S.I.
=== Fortification === According to the Global Fortification Data Exchange, vitamin K deficiency is so rare that no countries require that foods be fortified. The World Health Organization does not have recommendations on vitamin K fortification.
== Curtius rearrangement == The Bergmann degradation makes use of the azide degradation described by the Curtius rearrangement. Curtius also attempted to degrade benzoylated amino acids; however, his method involved splitting the carbamate with strongly energetic treatment with acids, which lead to decomposition of the resultant aldehyde and acid amides. This convinced Bergmann that Curtius' azide degradation could be followed by treatment with benzyl alcohol (his carbobenzoxy method) to isolate the resultant amino acid aldehyde and residual peptide amide for sequencing purposes.
Portugal's culture has developed due to the influence from various civilisations that have crossed Europe, especially the Mediterranean. Later, during the period of Portugal's engagement in the Age of Discovery, cultural elements from outside of Europe were introduced and became a central element of Portuguese national identity. Portugal is known for its heritage and architecture, sacred sites, festivities, poetry, its music (especially the fado), and cuisine (including its wine). As of 2026, UNESCO inscribed 17 properties in Portugal on the World Heritage List. Portugal's national day is on 10 June, celebrated as the Dia de Portugal, de Camões e das Comunidades Portuguesas (Portugal, Camões, and Portuguese Communities Day).
Sources: en.wikipedia.org
Research and Development, a "non-combative" modification that has been likened to Portal, in which the player uses the gravity gun and other aspects of the Source engine physics to solve puzzles and progress forward. Rexaura, a Portal modification developed by Ben "Mevious" Bryant featuring 20 (from 00 to 19) puzzles designed around manipulating and ricocheting energy pellets. Riot Act - A mod set in the Half-Life 2 universe, following a member of the civilian resistance on their escape from the Combine prison at Nova Prospekt.
=== Catalase === The catalase test tests whether a microbe produces the enzyme catalase, which catalyzes the breakdown of hydrogen peroxide. Smearing a colony sample onto a glass slide and adding a solution of hydrogen peroxide (3% H2O2) will indicate whether the enzyme is present or not. Bubbling is a positive test while nothing happening is a negative result.
As for the Basque Country, Rodríguez Zapatero announced shortly after having rejected on February 1, 2005, in the Congress of Deputies – with the support of the PP – the "Ibarretxe Plan", that he was willing to "dialogue" with ETA to put an end to terrorism. Almost a year later, on March 22, 2006, ETA announced a "permanent ceasefire" and that it would talk with the government about the "end of violence" if in parallel a "table of parties" was formed that would include the outlawed Batasuna. The PP's response was to accuse the government of having unilaterally broken the Antiterrorist Pact of 2000 and then subjected it to intense harassment both in the Cortes and in the streets, supporting the long series of demonstrations against the "surrender" to ETA called by the Association of Victims of Terrorism.
Blood smear examination is usually performed in conjunction with a complete blood count in order to investigate abnormal results or confirm results that the automated analyzer has flagged as unreliable. Microscopic examination of the shape, size, and coloration of red blood cells is useful for determining the cause of anemia. Disorders such as iron deficiency anemia, sickle cell anemia, megaloblastic anemia and microangiopathic hemolytic anemia result in characteristic abnormalities on the blood film. The proportions of different types of white blood cells can be determined from the blood smear. This is known as a manual white blood cell differential. The white blood cell differential can reveal abnormalities in the proportions of white blood cell types, such as neutrophilia and eosinophilia, as well as the presence of abnormal cells such as the circulating blast cells seen in acute leukemia. Qualitative abnormalities of white blood cells, like toxic granulation, are also visible on the blood smear. Modern complete blood count analyzers can provide an automated white blood cell differential, but they have a limited ability to differentiate immature and abnormal cells, so manual examination of the blood smear is frequently indicated. Blood smear examination is the preferred diagnostic method for certain parasitic infections, such as malaria and babesiosis. Rarely, bacteria may be visible on the blood smear in patients with severe sepsis.
=== Anesthesia === Esketamine is used for similar indications as ketamine. Such uses include induction of anesthesia in high-risk patients such as those with circulatory shock, severe bronchospasm, or as a supplement to regional anesthesia with incomplete nerve blocks. Esketamine binds more strongly to NMDA receptors than racemic ketamine, making it roughly twice as potent with faster recovery and fewer cognitive side effects; its pain relief benefits are somewhat inconsistent.
Sources: en.wikipedia.org
=== Neoantigens === Many tumors express mutations. These mutations potentially create new targetable antigens (neoantigens) for use in T-cell immunotherapy. The presence of CD8+ T cells in cancer lesions, as identified using RNA sequencing data, is higher in tumors with a high mutational burden. The level of transcripts associated with the cytolytic activity of natural killer cells and T cells positively correlates with mutational load in many human tumors. In non–small cell lung cancer patients treated with lambrolizumab, mutational load shows a strong correlation with clinical response. In melanoma patients treated with ipilimumab, the long-term benefit is also associated with a higher mutational load, although less significantly. The predicted MHC binding neoantigens in patients with a long-term clinical benefit were enriched for a series of tetrapeptide motifs that were not found in tumors of patients with no or minimal clinical benefit. However, human neoantigens identified in other studies do not show the bias toward tetrapeptide signatures. Finally, effectiveness of neoantigens may also be regulated by the specific HLA repertoire possessed by specific patient sub-groups.
is its oven dry mass (the attainment of constant mass generally after drying in an oven set at 103±2 °C (218±4 °F) for 24 hours as mentioned by Walker et al., 1993). The equation can also be expressed as a fraction of the mass of the water and the mass of the oven dry wood rather than a percentage. For example, 0.59 kg/kg (oven dry basis) expresses the same moisture content as 59% (oven dry basis).
Each country has its own laws and regulations for the import and export of goods into and out of a country, which its customs authority enforces. The import or export of certain goods may be restricted or prohibited, in which case customs controls enforce these policies. Customs enforcement at borders can also entail collecting excise tax and preventing the smuggling of dangerous or illegal goods. A customs duty is a tariff or tax on the importation (usually) or exportation (unusually) of goods. In many countries, border controls for arriving passengers at many international airports and some road crossings are separated into red and green channels to prioritise customs enforcement. Within the European Union's common customs area, airports may operate additional blue channels for passengers arriving from within that area. For such passengers, border control may focus specifically on prohibited items and other goods that are not covered by the common policy. Luggage tags for checked luggage travelling within the EU are green-edged to facilitate identification. In most EU member states, travellers coming from other EU countries within the Schengen Area can use the green lane. However, airports outside the Schengen Area, or those with frequent flights arriving from jurisdictions within the Schengen Area but outside the European Union, may use blue channels for convenience and efficiency. A customs area is a designated area for storing commercial goods that have not cleared border controls.
phosphate backbone Also phosphodiester backbone, sugar–phosphate backbone, and phosphate–sugar backbone. The linear chain of alternating phosphate and sugar compounds that results from the linking of consecutive nucleotides in the same strand of a nucleic acid molecule, and which serves as the structural framework of the nucleic acid. Each individual strand is held together by a repeating series of phosphodiester bonds connecting each phosphate group to the ribose or deoxyribose sugars of two adjacent nucleotides. These bonds are created by ligases and broken by nucleases.
Sources: en.wikipedia.org
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.
Epitalon and epithalon both circulate, and the difference reflects transliteration of a name coined in Russian-language publications. Reference to the extract it derives from, epithalamin, explains the shared stem. Databases and suppliers are inconsistent, so a search for one spelling alone may miss relevant entries.
No. Epithalamin is a multi-component preparation obtained from pineal tissue, and its exact composition is not fully characterised. Epitalon is a single defined tetrapeptide described as a short synthetic counterpart of that extract, so the two are related in origin but not interchangeable in identity.
The powder is normally kept at −20 °C or below in a sealed, moisture-protected container. Letting the vial reach room temperature before opening helps prevent condensation on the contents.