Everything below concerns GLP-1 receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
The primary target is the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises intracellular cyclic AMP, which potentiates glucose-dependent insulin secretion and lowers glucagon release when blood glucose is elevated. Signalling in the hypothalamus and brainstem is associated with reduced appetite and slower gastric emptying. Because the insulinotropic effect depends on prevailing glucose levels, the hypoglycaemic risk of the peptide alone is described as low in most study settings. The relative contribution of peripheral and central actions remains an active research question.
Large randomised trials in adults with type 2 diabetes and in adults with obesity have reported reductions in body weight and improvements in several cardiovascular risk markers. One outcome trial found a lower incidence of major adverse cardiovascular events in participants with diabetes and established cardiovascular disease. Gastrointestinal effects such as nausea and vomiting are the most frequently reported adverse events and often diminish over time. Changes in lean body mass during weight loss are an area of ongoing investigation. Effects in adolescents and in pregnancy are less well characterised, and current labelling advises against use during pregnancy.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released after nutrient intake. The molecule contains 31 amino acid residues and differs from the native sequence at several positions. A non-natural residue at position eight resists the enzyme that normally truncates the hormone, while a lysine-linked fatty diacid side chain promotes binding to serum albumin. These two modifications extend the circulating half-life from minutes to roughly one week. The peptide is produced by solid-phase synthesis followed by selective acylation, and its identity and purity are confirmed by spectrometric and chromatographic techniques.
Certificate of analysis documents from suppliers typically report purity by chromatographic area, water content, and counter-ion identity. Independent verification is advisable because reported values can be generated under differing conditions. Impurity profiles matter for research use, where aggregates, deamidation products, and residual solvents may influence experimental results. Container, lot, and chain-of-custody records support traceability. Analytical results are method-dependent, so comparisons between laboratories require the same procedure and reference standards.
Lyophilized peptide material is typically stored at or below -20 °C, with -80 °C used for longer-term archives. Vials should remain sealed and desiccated because moisture promotes aggregation and hydrolysis. Repeated freeze-thaw cycles are avoided since they can alter peptide conformation and reduce recovery. Once reconstituted, solutions are generally kept at 2-8 °C and used within a defined window. Stability beyond those windows depends on buffer composition and concentration, and exact limits are product-specific rather than universal.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Acylated GLP-1 receptor agonist | 31-residue synthetic peptide |
| Molecular formula | C187H291N45O59 | established for the free peptide |
| Appearance | White to off-white powder | as supplied before formulation |
| Solubility | Freely soluble in water | aqueous buffers near neutral pH |
| Typical storage | 2 to 8 degrees Celsius, protected from light | powder and solution forms differ in shelf life |
Clinical development of this compound followed earlier short-acting GLP-1 analogues that required frequent injection. Once-weekly subcutaneous formulations entered use after 2017, and an oral formulation using a permeation enhancer later became available. The oral version pairs the peptide with sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, a carrier that improves uptake across the gastric epithelium. Interest has expanded from glycaemic control into weight management and metabolic liver disease. Regulatory status and approved indications differ between countries, and the product remains subject to ongoing safety monitoring.
Semaglutide is a synthetic peptide that acts as an agonist at the glucagon-like peptide-1 receptor. It is a structural analogue of human GLP-1(7-37), modified to resist enzymatic degradation by dipeptidyl peptidase-4. The peptide backbone contains alpha-aminoisobutyric acid at position 8, a substitution that stabilises the helix and slows cleavage. A fatty diacid side chain attached through a linker at lysine 34 promotes binding to serum albumin, which extends the circulating half-life. These two modifications together allow less frequent administration than native GLP-1 requires.
Native GLP-1 is degraded rapidly by dipeptidyl peptidase-4. Semaglutide resists this cleavage because alanine at position 8 is replaced by alpha-aminoisobutyric acid. A second substitution at position 34 introduces arginine, which further stabilizes the peptide. The most distinctive modification is a spacer and C18 fatty diacid attached at lysine 26, enabling strong albumin affinity. These three changes together produce a half-life measured in days rather than minutes, and the same structural logic underlies other long-acting analogs in this class.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1, a hormone released from intestinal L-cells after food intake. It contains 31 amino acids and differs from native GLP-1 through modifications that slow enzymatic breakdown. The peptide was developed to extend the short circulating half-life of endogenous GLP-1, which is measured in minutes. Researchers introduced the compound in the early 2010s. Two backbone changes and a fatty acid side chain define its structure, distinguishing it from earlier GLP-1 receptor agonists.
The compound binds the GLP-1 receptor on pancreatic beta cells and other tissues, activating a G-protein signaling cascade that raises intracellular cyclic AMP. This action increases glucose-dependent insulin secretion when blood glucose is elevated, while binding also slows gastric emptying and reduces glucagon release. In the central nervous system, receptor activation in the hypothalamus and brainstem contributes to reduced appetite. The fatty acid chain binds albumin, which protects the peptide from renal filtration and enzymatic degradation. This albumin binding is central to its extended circulation time.
The sequence incorporates alpha-aminoisobutyric acid at position 8, replacing the alanine found in the natural hormone. This substitution blocks the primary DPP-4 recognition site and contributes most of the enzymatic stability. Albumin binding further protects the peptide and reduces the frequency of administration required to maintain active plasma levels. Because the fatty acid chain increases lipophilicity, the compound is formulated as a solution rather than a simple aqueous buffer. Researchers describe the design as an incremental optimization of earlier GLP-1 analogs rather than a wholly new scaffold.
Reported molecular weight is approximately 4113.6 daltons for the free base, and the peptide is supplied as a lyophilized powder or in buffered liquid form depending on the intended use. It is freely soluble in water when formulated with appropriate excipients, though the unconjugated peptide shows limited stability at neutral pH over long periods. Analytical characterization typically relies on reversed-phase high-performance liquid chromatography and mass spectrometry. Purity specifications for research-grade material commonly exceed ninety-five percent by area. Isotopic and impurity profiles differ between suppliers.
Two principal therapeutic variants exist under separate regulatory filings, one indicated for glycemic control in type 2 diabetes and one for chronic weight management. Both use the same active molecule; differences lie in formulation strength, titration schedule, and labeling. Regulatory agencies in the United States and European Union approved injectable forms in 2017 and 2018 respectively. An oral tablet formulation received approval later, using a carrier molecule to enhance absorption across the gastric epithelium. Labeling differs by jurisdiction and by indication.
Storage guidance for the finished injectable product distinguishes the unused state from the in-use state. Before first use, pens are kept refrigerated between 2 and 8 degrees Celsius, protected from light, and never frozen, since freezing can disrupt the peptide or the device. After first use, label instructions in several markets permit storage at room temperature up to about 30 degrees Celsius for a limited number of days. Solid research-grade material is normally held at or below minus 20 degrees Celsius, often with desiccant, and allowed to equilibrate before opening.
Quantification and purity assessment rely on separation methods coupled to optical or mass detection. Reversed-phase high-performance liquid chromatography resolves the intact peptide from related impurities and is the standard assay technique. Size-exclusion chromatography measures aggregates, while ion-exchange chromatography separates charge variants produced by deamidation. Mass spectrometry confirms identity and detects mass shifts of a few daltons. In biological matrices, liquid chromatography with tandem mass spectrometry is often used because immunoassays can cross-react with endogenous GLP-1 or with circulating fragments.
As a peptide, semaglutide is sensitive to conditions that break amide bonds or modify side chains. Deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation are the main degradation routes described in published stability work. Rate depends strongly on pH, buffer species, ionic strength, temperature and exposure to light. Formulators therefore choose a defined solution pH and often add excipients such as phosphate buffer, propylene glycol and phenol, each of which plays a separate role in pH control, tonicity or preservation.
=== Medical === Indigenous healers in Africa use different parts of the locust bean tree for health benefits. In a survey conducted on healers in Togo, Parkia biglobosa was one of the highest cited plants used for treating hypertension. The tree was also one of two plants "listed as having real wound-healing properties in South-Western Nigeria, influencing the proliferation of dermal fibroblasts significantly." In a similar survey conducted in Guinea relating to their use of antimalarial plants, Parkia biglobosa was cited among those most often successfully used. In an analysis on the antibacterial properties of the plant, another study found that "these properties compare favourably with those of streptomycin, making it a potential source of compounds used in the management of bacterial infections."
=== From specimen collection === Most causes of in vitro hemolysis are related to specimen collection. Difficult collections, unsecure line connections, contamination, and incorrect needle size, as well as improper tube mixing and incorrectly filled tubes are all frequent causes of hemolysis. In vitro hemolysis during specimen collection can cause inaccurate laboratory test results by contaminating the surrounding plasma with the contents of hemolyzed red blood cells. For example, the concentration of potassium inside red blood cells is much higher than in the plasma and so an elevated potassium level is usually found in biochemistry tests of hemolyzed blood. After the blood collection process, in vitro hemolysis can still occur in a sample due to external factors, such as prolonged storage, incorrect storage conditions and excessive physical forces by dropping or vigorously mixing the tube.
=== New album and arena successes (2025–present) === Following a seven-year studio recording hiatus, the group announced sessions for their eighth studio album under the working title Potop ("Deluge"). In late 2025, they released the lead single "Moja jedina,". The accompanying tour circuit saw the group sell out consecutive theater and club dates across the former Yugoslavia, including performances at Zagreb's Boogaloo and Boćarski Dom. Throughout the summer of 2026, the band headlined major regional outdoor events, including the 59th Gitarijada u Zaječaru, Arsenal Fest, Ljubljana and a concert at Pula's Kaštel. On September 5, 2026, Goran Bare & Majke performed a massive standalone headline show at the open-air Šalata Stadium in Zagreb, marking their largest outdoor performance in the capital city since 2018. Unprecedented lineup stability historically known for frequent and abrupt personnel changes, the era since 2015 marks the most stable period in the band's four-decade history. On 21 September 2026, the band ended a concert in Makarska early due to Goran Bare's health issues preventing him from completing the first song. Bare died on 9 October 2026, at the age of 61.
After the award ceremony in Sweden, a banquet is held in the Blue Hall at the Stockholm City Hall, which is attended by the Swedish Royal Family and around 1,300 guests. The Nobel Peace Prize banquet is held in Norway at the Oslo Grand Hotel after the award ceremony. Apart from the laureate, guests include the president of the Storting, on occasion the Swedish prime minister, and, since 2006, the King and Queen of Norway. In total, about 250 guests attend.
The Soviet Union constructed a series of fast reactors, the first being mercury-cooled and fueled with plutonium metal, and the later plants sodium-cooled and fueled with plutonium oxide. BR-1 (1955) was 100W (thermal) was followed by BR-2 at 100 kW and then the 5 MW BR-5. BOR-60 (first criticality 1969) was 60 MW, with construction started in 1965.
Sources: en.wikipedia.org
Copper-free click chemistry is a bioorthogonal reaction as a variant of an azide-alkyne Huisgen cycloaddition. By eliminating cytotoxic copper catalysts, the reaction proceeds without live-cell toxicity. It was developed as a faster alternative to the Staudinger ligation with the first generation of Cu-free click chemistry, producing rate constants over 63 times faster. Although the reaction produces a regioisomeric mixture of triazoles, the lack of regioselectivity in the reaction is not a major concern for its applications in bioorthogonal chemistry. More regiospecific and less bioorthogonal requirements are best served by the traditional Huisgen cycloaddition, especially given the low yield and synthetic difficulty of synthesizing a strained cyclooctyne (compared to the addition of a terminal alkyne). The bioorthogonality of the reaction has allowed the Cu-free click reaction to be applied within cultured cells, live zebrafish, and mice. The absence of exogenous metal catalysts makes the Cu-free chemical reactions suitable for the in vivo applications of bioorthogonal chemistry or bioorthogonal click chemistry.
==== Agriculture and land ==== Liu Wenhui's agricultural policy put much emphasis on wage laborers working under state-owned enterprises, a marked departure from Zhao Erfeng's more explicitly colonialist model of settlers working on state-owned land. In 1939, the Agriculture Improvement Institute was formed and embarked on a variety of projects across Xikang, including fertilizer plants, ranches, farms, plantations, and sericulture. In addition, the Institute installed weather monitoring stations across the province. Due to a lack of resources, none of these projects were particularly successful, save for perhaps the farm at Taining which was 2.5 million mu in area and remained in existence as of 2021. Although Liu maintained the Zhao-era policy that all wasteland or non-cultivated areas (huang) were state-owned, in practice state farms ended up renting even huang areas from landowners. This was because in the early Republican era, the government began selling deeds to the land in Xikang and charging taxes on the sale of deeds, deriving much profit from it. This state of affairs was not addressed by the Liu administration, perhaps due to the fact that much of the Qing-era uncultivated land was already being utilized. By 1940, income from the deed tax was equivalent to around one-third of that of the land tax.
=== Regulatory agencies === In the US, the Food and Drug Administration (FDA) can audit the files of local site investigators after they have finished participating in a study, to see if they were correctly following study procedures. This audit may be random, or for cause (because the investigator is suspected of fraudulent data). Avoiding an audit is an incentive for investigators to follow study procedures. A 'covered clinical study' refers to a trial submitted to the FDA as part of a marketing application (for example, as part of an NDA or 510(k)), about which the FDA may require disclosure of financial interest of the clinical investigator in the outcome of the study. For example, the applicant must disclose whether an investigator owns equity in the sponsor, or owns proprietary interest in the product under investigation. The FDA defines a covered study as "any study of a drug, biological product or device in humans submitted in a marketing application or reclassification petition that the applicant or FDA relies on to establish that the product is effective (including studies that show equivalence to an effective product) or any study in which a single investigator makes a significant contribution to the demonstration of safety". Alternatively, many American pharmaceutical companies have moved some clinical trials overseas. Benefits of conducting trials abroad include lower costs (in some countries) and the ability to run larger trials in shorter timeframes, whereas a potential disadvantage exists in lower-quality trial management.
== Biological function == Enzymes serve a wide variety of functions inside living organisms. They are indispensable for signal transduction and cell regulation, often via kinases and phosphatases. They also generate movement, with myosin hydrolyzing adenosine triphosphate (ATP) to generate muscle contraction, and also transport cargo around the cell as part of the cytoskeleton. Other ATPases in the cell membrane are ion pumps involved in active transport. Enzymes are also involved in more exotic functions, such as luciferase generating light in fireflies. Viruses can also contain enzymes for infecting cells, such as the HIV integrase and reverse transcriptase, or for viral release from cells, like the influenza virus neuraminidase. An important function of enzymes is in the digestive systems of animals. Enzymes such as amylases and proteases break down large molecules (starch or proteins, respectively) into smaller ones, so they can be absorbed by the intestines. Starch molecules, for example, are too large to be absorbed from the intestine, but enzymes hydrolyze the starch chains into smaller molecules such as maltose and eventually glucose, which can then be absorbed. Different enzymes digest different food substances. In ruminants, which have herbivorous diets, microorganisms in the gut produce another enzyme, cellulase, to break down the cellulose cell walls of plant fiber.
Octreotide is used in nuclear medicine imaging by labeling with indium-111 (Octreoscan) to noninvasively image neuroendocrine and other tumours expressing somatostatin receptors. It has been radiolabeled with carbon-11 as well as gallium-68 (using edotreotide), enabling imaging with positron emission tomography (PET).
Sources: en.wikipedia.org
Lowered Notch1 expression resulted in no tadpole tail regeneration, and induced Notch1 expression was able to partially rescue tail regeneration in the form of the notochord and spinal cord (but very little musculature.) Moreover, Wnt/beta-catenin activation has shown promising results in its involvement with dedifferentiation. In both a human epithelial cell transplant into mice and in vitro epithelial cell model, the activated canonical Wnt signaling pathway was found to be necessary for dedifferentiation. When in conjunction with Nanog, the canonical Wnt pathway also induced partial dedifferentiation in zebrafish endothelial cells, as seen by an increase in cell cycle re-entry and loss of cellular adhesion.
== Product range == The Femarelle product range was developed to address the changing needs of women throughout different stages of menopause. Each formulation combines DT56a with selected vitamins, minerals, or botanical ingredients tailored to specific menopausal concerns.
== Medical uses == Zalcitabine was the third antiretroviral to be approved by the Food and Drug Administration (FDA) for the treatment of HIV/AIDS. It was approved on June 19, 1992, as a monotherapy and again in 1996 for use in combination with zidovudine (AZT). Using combinations of NRTIs was in practice prior to the second FDA approval and the triple drug combinations with dual NRTIs and a protease inhibitor (PI) were not far off by this time. In 1992 dideoxycytidine was listed as a specialty drug. The sale and distribution of zalcitabine has been discontinued since December 31, 2006.
== Research and career == Pratt works in atmospheric chemistry. She was appointed to the faculty at the University of Michigan in 2013. She is interested in various chemical reactions that occur in the environment, including those that occur between trace gases, in aqueous solutions and on surfaces. Primary atmospheric particles can originate from natural and human-made sources, which include sea spray, soot and bacteria. These undergo various reactions and can form secondary atmospheric particles, evolving into dynamical chemical mixtures such as aerosols. These particles can take on a variety of different sizes, between 3 nm and 10 μm. Pratt investigates the interactions between trace gases and clouds using mass spectrometry. She is particularly interested in the atmospheric composition of winter environments, for example, in the Polar regions. The Arctic is undergoing a rapid loss of sea ice. Pratt makes use of mass spectrometries to various degrees of sensitivity, for examples aerosol time-of-flight mass spectrometry (aerosols of 0.07 – 1.6 μm diameter), chemical ionization mass spectrometry (gases at sub parts per trillion) and ambient ion mass spectrometry. These results are combined with one-dimensional modelling to understand how atmospheric compositions as a function of altitude and time. She looks to establish the feedbacks between human-made emissions, aerosols and the Earth to better predict air quality. In 2018, she started a United States Department of Energy project to use single particle mass spectrometry during the Polar night.
According to the United States Geological Survey (USGS), 10,200 tonnes of bismuth were produced worldwide by mining and 17,100 tonnes by refining in 2016. Since then, USGS does not provide mining data for bismuth, considering them unreliable. Globally, bismuth is mostly produced by refining, as a byproduct of extraction of other metals such as lead, copper, tin, molybdenum, and tungsten, though the refining-to-mining ratio depends on the country. Bismuth travels in crude lead bullion (which can contain up to 10% bismuth) through several stages of refining, until it is removed by the Kroll-Betterton process, which separates the impurities as slag, or the electrolytic Betts process. Bismuth behaves similarly with another of its major metals, copper. The raw bismuth metal from both processes contains still considerable amounts of other metals, foremost lead. By reacting the molten mixture with chlorine gas, the metals are converted to their chlorides, while bismuth remains unchanged. Impurities can also be removed by various other methods, for example, with fluxes and treatments yielding high-purity bismuth metal (over 99% Bi).
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and neutral endopeptidases. Semaglutide carries a non-natural amino acid at position eight that blocks that cleavage, and a fatty diacid side chain that binds albumin. The result is a much longer duration of action than the native hormone.
The fatty diacid chain associates strongly with serum albumin, which keeps the peptide in circulation and shields it from rapid renal clearance. Bound peptide is released gradually, producing a sustained receptor signal. This mechanism also reduces the peak-to-trough variation seen with shorter-acting analogues.
The balance between peripheral receptor activation and signalling in the central nervous system is not fully resolved. The extent to which slowed gastric emptying accounts for reduced energy intake, compared with direct effects on appetite circuits, is debated. Long-term effects on lean mass and on tissues outside the gut and brain are still under study.
The lyophilized powder is dissolved in a suitable solvent, often sterile water or a buffered diluent, with gentle mixing rather than vigorous shaking. Foaming and shear should be avoided because they can promote aggregation. The resulting solution is then stored cold and protected from light.