AEDG raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-08-31. Anything still debated is marked as such rather than presented as settled.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
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.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Calculated from the four residues with three water losses |
| Molecular mass | About 390.35 g/mol | Monoisotopic mass near 390.14, used for mass-spectrometric identification |
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG; no disulfide bonds or modified residues |
| Appearance | White to off-white solid | Supplied as a dried powder |
| Isoelectric point | Around 4 | Estimated from aspartate and glutamate side-chain pKa values |
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
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.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
where Ep is potential energy, q is the charge of the particle, and U is the electric potential difference (also known as voltage). When the charged particle is accelerated into time-of-flight tube (TOF tube or flight tube) by the voltage U, its potential energy is converted to kinetic energy. The kinetic energy of any mass is:
== Medical uses == Metribolone was never approved for medical use, a situation unlikely to change given its liver toxicity even at low doses. It was studied for the potential treatment of advanced breast cancer in women but development was abandoned.
The WHO Model List of Essential Medicines (a.k.a. Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health system. The list is frequently used by countries to help develop their own local lists of essential medicines. As of 2016, more than 155 countries have created national lists of essential medicines based on the World Health Organization's model list. This includes both developed and developing countries. The list is divided into core items and complementary items. The core items are deemed to be the most cost-effective options for key health problems and are usable with little additional health care resources. The complementary items either require additional infrastructure such as specially trained health care providers or diagnostic equipment or have a lower benefit–cost ratio. About 25% of items are in the complementary list. Some medications are listed as both core and complementary. While most medications on the list are available as generic products, being under patent does not prevent inclusion. The first list was published in 1977 and included 208 medications. The WHO updates the list every two years. There are 306 medications in the 14th list in 2005, 410 in the 19th list in 2015, 433 in the 20th list in 2017, 460 in the 21st list in 2019, and 479 in the 22nd list in 2021. Various national lists contain between 334 and 580 medications. The Essential Medicines List (EML) was updated in September 2025 to its 24th edition.
These reactive oxygen species and their reaction products, such as the hydroxyl radical, are very harmful to cells, as they oxidize proteins and cause mutations in DNA. This cellular damage may contribute to disease and is proposed as one cause of aging. The cytochrome c oxidase complex is highly efficient at reducing oxygen to water, and it releases very few partly reduced intermediates; however small amounts of superoxide anion and peroxide are produced by the electron transport chain. Particularly important is the reduction of coenzyme Q in complex III, as a highly reactive ubisemiquinone free radical is formed as an intermediate in the Q cycle. This unstable species can lead to electron "leakage" when electrons transfer directly to oxygen, forming superoxide. As the production of reactive oxygen species by these proton-pumping complexes is greatest at high membrane potentials, it has been proposed that mitochondria regulate their activity to maintain the membrane potential within a narrow range that balances ATP production against oxidant generation. For instance, oxidants can activate uncoupling proteins that reduce membrane potential. To counteract these reactive oxygen species, cells contain numerous antioxidant systems, including antioxidant vitamins such as vitamin C and vitamin E, and antioxidant enzymes such as superoxide dismutase, catalase, and peroxidases, which detoxify the reactive species, limiting damage to the cell.
Sources: en.wikipedia.org
The lungs of birds are relatively small, but are connected to eight or nine air sacs that extend through much of the body, and are in turn connected to air spaces within the bones. On inhalation, air travels through the trachea of a bird into the air sacs. Air then travels continuously from the air sacs at the back, through the lungs, which are relatively fixed in size, to the air sacs at the front. From here, the air is exhaled. These fixed size lungs are called "circulatory lungs", as distinct from the "bellows-type lungs" found in most other animals. The lungs of birds contain millions of tiny parallel passages called parabronchi. Small sacs called atria radiate from the walls of the tiny passages; these, like the alveoli in other lungs, are the site of gas exchange by simple diffusion. The blood flow around the parabronchi and their atria forms a cross-current process of gas exchange (see diagram on the right). The air sacs, which hold air, do not contribute much to gas exchange, despite being thin-walled, as they are poorly vascularised. The air sacs expand and contract due to changes in the volume in the thorax and abdomen. This volume change is caused by the movement of the sternum and ribs and this movement is often synchronised with movement of the flight muscles. Parabronchi in which the air flow is unidirectional are called paleopulmonic parabronchi and are found in all birds. Some birds, however, have, in addition, a lung structure where the air flow in the parabronchi is bidirectional. These are termed neopulmonic parabronchi.
=== Industry influence on research === In 2015, the New York Times published an article on the Global Energy Balance Network, a nonprofit founded in 2014 that advocated for people to focus on increasing exercise rather than reducing calorie intake to avoid obesity and to be healthy. The organization was founded with at least $1.5M in funding from the Coca-Cola Company, and the company has provided $4M in research funding to the two founding scientists Gregory A. Hand and Steven N. Blair since 2008.
== Biosynthesis == Kynurenine gives its name to the kynurenine pathway which leads from the amino acid tryptophan to many important enzyme cofactors including niacin and nicotinamide adenine dinucleotide.
== Pathophysiology == Myxedema describes a specific form of cutaneous and dermal edema secondary to increased deposition of connective tissue components. The connective fibres are separated by an increased amount of protein and glycosaminoglycans. This protein-mucopolysaccharide complex binds water, producing non-pitting boggy edema, in particular around eyes, hands, feet and in the supraclavicular fossae. This deposition involves not only the skin but also the tongue, myocardium, kidney medulla, lung, intestine and most other organs of the body (apart from the stomach). Myxoedema is also responsible for the thickening of the laryngeal and pharyngeal mucous membranes, which results in thick slurred speech and hoarseness, both of which are seen commonly in hypothyroidism. The accumulation of glycosaminoglycans (GAGs) in the dermal tissues consists characteristically of hyaluronic acid with very little change in the dermatan sulfate abundance and perhaps a decrease in chondroitin sulfate. The tissue change in myxedema can be related directly to the physicochemical properties of hyaluronate. Its hygroscopic nature allows it to swell to one thousand times its dry weight when hydrated. The pathogenesis of generalized myxedema is thought to be fairly well understood and related to the deficiency of thyroid hormone, but the pathogenesis of pretibial and orbital myxedema due to Graves' disease is not fully understood, however, two mechanisms predominate:
An electrocardiogram (ECG) is a recording of the heart's electrical activity, acquired using electrodes placed on the skin. The taking of an ECG is an important part of the workup of an AMI, and ECGs are often not just taken once but may be repeated over minutes to hours, or in response to changes in signs or symptoms. ECG readouts produce a waveform with different labeled features. In addition to a rise in biomarkers, a rise in the ST segment, changes in the shape or flipping of T waves, new Q waves, or a new left bundle branch block can be used to diagnose an AMI. In addition, ST elevation can be used to diagnose an ST segment myocardial infarction (STEMI). A rise must be new in V2 and V3 ≥2 mm (0.2 mV) for males or ≥1.5 mm (0.15 mV) for females or ≥1 mm (0.1 mV) in two other adjacent chest or limb leads. ST elevation is associated with infarction, and may be preceded by changes indicating ischemia, such as ST depression or inversion of the T waves. Abnormalities can help differentiate the location of an infarct, based on the leads that are affected by changes. Early STEMIs may be preceded by peaked T waves. Other ECG abnormalities relating to complications of acute myocardial infarctions may also be evident, such as atrial or ventricular fibrillation.
Sources: en.wikipedia.org
These competitions are now known as the A-League Men, A-League Women and A-League Youth. On 15 May 2024, FA won the rights to host the 2026 AFC Women's Asian Cup. On 11 February 2025, a second tier Australian Championship was announced. On 15 January 2026, FA announced former Stan CEO Martin Kugeler as its new CEO, taking over from interim CEO Heather Garriock who took the role in May 2025, following the departure of James Johnson.
In 1947, David Lester and Leon Greenberg found strong evidence that paracetamol was a major metabolite of acetanilide in human blood, and in a subsequent study, they reported that large doses of paracetamol given to albino rats did not cause methemoglobinemia. In 1948, Bernard Brodie, Julius Axelrod and Frederick Flinn confirmed that paracetamol was the major metabolite of acetanilide in humans, and established that it was just as efficacious an analgesic as its precursor. They also suggested that methemoglobinemia is produced in humans mainly by another metabolite, phenylhydroxylamine. A follow-up paper by Brodie and Axelrod in 1949 established that phenacetin was also metabolized to paracetamol. This led to a "rediscovery" of paracetamol. Paracetamol was first marketed in the United States in 1950 under the name Trigesic, a combination of paracetamol, aspirin, and caffeine. Reports in 1951 of three users stricken with the blood disease agranulocytosis led to its removal from the marketplace, and it took several years until it became clear that the disease was unconnected. The following year, 1952, paracetamol returned to the U.S. market as a prescription drug. In the United Kingdom, marketing of paracetamol began in 1956 by Sterling-Winthrop Co. as Panadol, available only by prescription, and promoted as preferable to aspirin since it was safe for children and people with ulcers.
Demon receives a warning from Fast Forward's former foster sister Rose Dartnell (who Fast Forward previously referred to as his potential girlfriend) about his violent tendencies, sharing he regularly tried to kill his foster siblings and left her permanently scarred in a murder attempt. Despite this, Rose loves him and wants to “fix him”. Demon tries to see the ocean by traveling east with Fast Forward, Emmy and Maggot. This trip is cancelled when Fast Forward reaches Richmond and, having completed a drug deal, turns around. Dori's father dies, wrecking her emotionally. Demon drops out of school and moves in with Dori. They both become increasingly dependent on pain killers as they live in squalor. Emmy also becomes heavily involved in drugs and runs away with Fast Forward as June loses track of her. Rose tells Demon that Fast Forward uses his girlfriends as “bait” for drug dealers in Mexico, and that Emmy is most likely being held hostage and raped. She gives him Emmy’s bracelet (a childhood gift from Demon) as evidence. After months of searching, June finds Emmy and rescues her from an Atlanta drug den with the assistance of Demon and her brother. June sends Emmy to an expensive rehab facility. U-Haul confronts Angus in the Winfield house, telling her Coach Winfield has been embezzling funds. He threatens to expose Coach if Angus doesn’t sleep with him, revealing he has been sexually obsessed with her since she was a young child, watching her and taking her clothing. A terrified Angus calls Demon for help.
The term "isotope", Greek for "at the same place", was suggested to Soddy by Margaret Todd, a Scottish physician and family friend, during a conversation in which he explained his ideas to her. He received the 1921 Nobel Prize in Chemistry in part for his work on isotopes.
Sources: en.wikipedia.org
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.
It is not recognised as an endogenous peptide hormone. The four-residue sequence can appear inside larger proteins and in digestive fragments of dietary protein, but no dedicated pathway producing it as a signalling molecule has been identified.
Several cell-culture reports describe increased telomerase activity after treatment, measured by enzyme assays or by transcript levels. Results differ between cell types and laboratories, and measured telomere lengthening has been reported in some studies but not in others, which leaves the physiological relevance open.
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.