Everything below concerns certificate of analysis. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
| 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 |
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
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.
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.
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.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
In 1869 Dmitrii Mendeleev reported that when he arranged the elements in a row according to their atomic weights, there was a certain periodicity to them. For instance, the second element, lithium, had similar properties to the ninth element, sodium, and the sixteenth element, potassium — a period of seven. Likewise, beryllium, magnesium, and calcium were similar and all were seven places apart from each other on Mendeleev's table. Using these patterns, Mendeleev predicted the existence and properties of new elements, which were later discovered in nature: scandium, gallium, and germanium. Moreover, the periodic table could predict how many atoms of other elements that an atom could bond with — e.g., germanium and carbon are in the same group on the table and their atoms both combine with two oxygen atoms each (GeO2 and CO2). Mendeleev found these patterns validated atomic theory because it showed that the elements could be categorized by their atomic weight. Inserting a new element into the middle of a period would break the parallel between that period and the next, and would also violate Dalton's law of multiple proportions.
If you are a libertarian you may find some nourishment in my book Letters to a Young Contrarian where I say that in the same breath as I-as I mourn the decay of some of my socialist allegiances that deep down I've always been a sympathizer of the libertarian anti-statist point of view. And one of the things that attracted me to socialism in the beginning was the idea of withering away of the state. In a 1986 video debate on Socialism vs Capitalism with John Judis VS Harry Binswanger and John Ridpath, Hitchens said:
==== Enzymatic ==== The enzymes traditionally used to digest heparin or HS are naturally produced by the soil bacterium Pedobacter heparinus (formerly named Flavobacterium heparinum). This bacterium is capable of using either heparin or HS as its sole carbon and nitrogen source. To do so, it produces a range of enzymes such as lyases, glucuronidases, sulfoesterases, and sulfamidases. The lyases have mainly been used in heparin/HS studies. The bacterium produces three lyases, heparinases I (EC 4.2.2.7), II (no EC number assigned) and III (EC 4.2.2.8) and each has distinct substrate specificities as detailed below.
== Hazards == Bottles of di-tert-butyl dicarbonate buildup of internal pressure in sealed containers caused by its slow decomposition to di-tert-butyl carbonate and ultimately tert-butanol and CO2 in the presence of moisture. For this reason, it is usually sold and stored in plastic bottles rather than glass ones. The main hazard of the reagent is its inhalational toxicity. Its median lethal concentration of 100 mg/m3 over 4 hours in rats is comparable to that of phosgene (49 mg/m3 over 50 min in rats).
Sources: en.wikipedia.org
Peukert wrote: "Eclectic as regards ideas, but up to date in its attitude to technology, National Socialism laid claims to offer a "conclusive" new answer to the challenges and discomforts of the modern age". Peukert wrote that: "The much heralded Volksgemeinschaft of the National Socialists in no way abolished the real contradictions of a modern industrial society; rather these were inadvertently aggravated by the use of highly modern industrial and propaganda techniques for achieving war readiness. In fact, the long-term characteristics of a modern industrial society, which had been interrupted by the world economic crisis, continued to run their course". Reflecting the influence of functionalist historians like Martin Broszat and Hans Mommsen, Peukert wrote the inability to achieve the idealized volksgemeinschaft of their dreams left the National Socialists increasingly frustrated and led them to lash out against groups considered to be enemies of the volksgemeinschaft as a way of compensation. Peukert argued that for the National Socialists "it was more important to travel hopefully than to arrive", as for the Nazis had no solutions to the problems of classical modernity other than a creating a sense of movement towards the vague goal of the utopian society that was to be the volksgemeinschaft. Peukert wrote the "violent answers" of the Nazis to the "contradictions of modernity" were not the basis of a successful social order, and as such the dynamism of the Nazi movement was primarily negative and the "movement" had a strong self-destructive streak.
As cirrhosis can be caused by many different entities that injure the liver in different ways, cause-specific abnormalities may be seen. For example, in chronic hepatitis B, there is infiltration of the liver parenchyma with lymphocytes. In congestive hepatopathy there are erythrocytes and a greater amount of fibrosis in the tissue surrounding the hepatic veins. In primary biliary cholangitis, there is fibrosis around the bile duct, the presence of granulomas and pooling of bile. Lastly in alcoholic cirrhosis, there is infiltration of the liver with neutrophils. Macroscopically, the liver is initially enlarged, but with the progression of the disease, it becomes smaller. Its surface is irregular, the consistency is firm, and if associated with steatosis, the color is yellow. Depending on the size of the nodules, there are three macroscopic types: micronodular, macronodular, and mixed cirrhosis. In the micronodular form (Laennec's cirrhosis or portal cirrhosis), regenerating nodules are under 3 mm. In macronodular cirrhosis (post-necrotic cirrhosis), the nodules are larger than 3 mm. Mixed cirrhosis consists of nodules of different sizes.
7-CPP antagonist SRIF-A CyCam cyclo(7-Ahep-Phe-Trp-Lys-Thr(Bzl)) cyclo(7-aminoheptanoylphenylalanyl-tryptophyl-lysyl-benzylthreonyl) cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl)) Cyclosomatostatin may have the possibility of treating complications of acute hemorrhage. Hepatic insulin sensitizing substance (HISS), a hormone, will be secreted by the liver which stimulates skeletal muscle glucose uptake when responding to insulin. This action makes up around 56% of total insulin action. Hemorrhage was shown to cause insulin resistance by this type of HISS-dependent insulin resistance (HDIR). Two animal tests were done, which shows that cyclosomatostatin can help prevent HDIR without correcting the hyperglycemic condition in the situation of hemorrhage and exogenous somatostatin infusion. Cyclosomatostatin may be related to other indications, including the potential of blocking the suppression of gastric emptying triggered by corticotropin-releasing hormone (CRH), the key regulator of the hypothalamic-pituitary-adrenal axis released to alter the body response caused by stress. Furthermore, cyclosomatostatin, even if used alone, may modulate neurotransmitter levels. It increases acetylcholine (ACh) release by reversing the inhibitory effect of a substance, DHP agonist Bay K 8844, to L-type voltage-sensitive Ca2+ calcium channel.
Candidates complete a Personal Fitness Test (PFT) upon arrival, which consists of at least 50 sit-ups in two minutes, 60 press-ups in two minutes, and a 1.5-mile (2.4 km) run in 10 minutes and 30 seconds. They then complete an Annual Fitness Test (AFT), which consists of marching 8 miles (13 km) in two hours while carrying 25 lb (11 kg) of equipment. Candidates then march cross-country against the clock, increasing the distance covered each day; this culminates in an endurance test known as the "Endurance", in which candidates march 40 miles (64 km) with full equipment before climbing up and down the mountain Pen y Fan (886 m; 2,907 ft) in 20 hours. By the end of this phase, candidates must then be able to run 4 miles (6.4 km) in 30 minutes or less and swim 2 miles (3.2 km) in 90 minutes or less. After completing aptitude phase, officer candidates are required to spend a week assessing their ability to carry out planning for UKSF operations while fatigued and stressed. Following mountain training, the jungle phase takes place in Belize, Brunei, or Malaysia. Candidates are taught navigation, patrol formation and movement, and jungle survival skills. Candidates then return to the UK to begin training in battle plans and foreign weapons, and then take part in combat survival exercises, ending in week-long escape and evasion training. Candidates are formed into patrols and, with nothing more than a tin can filled with survival equipment, are dressed in World War II-era uniforms and told to head for a particular destination by sunrise.
==== Possible roles in pathophysiology ==== Astrocytes can transfer mitochondria into adjacent neurons to improve neuronal function. It is therefore plausible that the damage to astrocyte mitochondria seen in GP astrocytes could affect the activity of neurons. A number of hypothalamic functions show declines in aging that may be related to GP astrocytes. For example, GP astrocytes are in close contact with neurons that make a neurotransmitter called dopamine in both the rat and human hypothalamus. The dopamine produced by these neurons is carried to the nearby pituitary gland to inhibit the release of a hormone called prolactin from the pituitary. The activity of dopaminergic neurons declines during aging, leading to elevations in blood levels of prolactin that can provoke breast cancer. An aging-associated change in astrocyte function might contribute to this change in dopaminergic activity. FABP7+ astrocytes are in close contact with neurons in the arcuate nucleus of the hypothalamus that are responsive to a hormone called leptin that is produced by fat cells. Leptin-sensitive neurons regulate appetite and body weight. FABP7+ astrocytes regulate the responsiveness of these neurons to leptin. Mitochondrial damage in these astrocytes could thus alter the function of leptin-sensitive neurons and could contribute to an aging-associated dysregulation of feeding and body weight. GP astrocytes may also be involved in the hypothalamic regulation of overall glucose metabolism.
Sources: en.wikipedia.org
==== Lamarckian inheritance ==== Similarly, his experiments with Wilfred Eade Agar to test William McDougall's supposed demonstration of Lamarckian inheritance of training in rats were negative and showed the inadequacy of McDougall's controls, the first results being published in 1935.
=== Head of intelligence === Noriega proved to be a very capable head of intelligence. During his tenure, he exiled 1,300 Panamanians whom he viewed as threats to the government. He also kept files on several officials within the military, the government, and the judiciary, allowing him to blackmail them later. Noriega also held the positions of head of the political police and head of immigration. His tenure was marked by intimidation and harassment of opposition parties and their leaders. He was described as doing much of Torrijos's "dirty work". For instance, Noriega ordered the death of Jesús Héctor Gallego Herrera, a priest whose work at an agricultural cooperative was seen as a threat by the government. Gallego's body is reported to have been thrown from a helicopter into the sea. He also made an effort during this period to portray Panama as a hub of enforcement against drug smuggling, possibly as a result of pressure from Torrijos. By the early 1970s, American law enforcement officials had reports of Noriega's possible involvement with narcotics trafficking. No formal criminal investigations were begun, and no indictment was brought: according to Dinges, this was due to the potential diplomatic consequences. This evidence included the testimony of an arrested boat courier, and of a drug smuggler arrested in New York. Though Torrijos frequently promised the U.S. cooperation in dealing with drug smuggling, Noriega would have headed any effort at enforcement, and the U.S. began to see Noriega as an obstacle to combatting drug smuggling. Dinges writes that the U.S.
On 16 March 1935, Deputy Premier Alick McCallum resigned from the Ministry and from Parliament. On 26 March, Frank Wise filled the vacancy in the Executive Council whilst a reshuffle took place amongst some of the lower-order ministers.
== Reception == Action Half-Life was the favored modification for a small subculture described by Rock, Paper, Shotgun's writer Quintin Smith as a "mad cabal of mappers who obsessed over easter eggs", with some levels containing secret areas much larger and more complex than the main level. These often included whole story-lines, puzzles, and scripted sequences. IGN said the game is a standard shooter aside from the stunts and although they look cool, they get tiresome quickly. PC Games liked the level design and said the game is more suited for experienced players. XtremPC played the beta 2.7 version and said the game is far below the quality of Action Quake 2. CNET Gamecenter placed it on its list of top 10 Half-Life mods, writing: "Action Half-Life, however, manages to capture a sense of danger and suspense that's missing from most frag-a-minute deathmatches."
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.
Reversed-phase high-performance liquid chromatography is run alongside mass spectrometry. The chromatogram separates components and gives a purity figure, while the mass spectrum confirms that the measured molecular mass matches the expected sequence. Neither measurement on its own is treated as sufficient.