The short version of incretin fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-05-01. Anything still debated is marked as such rather than presented as settled.
Storage at minus 20 degrees Celsius or lower in a desiccated container preserves the peptide for extended periods, while working solutions are commonly held at two to eight degrees Celsius for short intervals. Light exposure and repeated freeze-thaw cycles accelerate degradation, so dividing material into single-use aliquots is generally recommended. Adsorption to glass and plastic surfaces can lower the measured concentration of dilute solutions, particularly below one milligram per millilitre. The degradation routes most often reported for GLP-1 analogues are deamidation, methionine oxidation, and backbone hydrolysis. Relative rates under specific conditions are frequently described only for individual formulations.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 or 280 nanometres is widely used to assess purity and to resolve related impurities. Liquid chromatography coupled to mass spectrometry confirms identity through the protonated molecular ion and fragment ions formed in tandem experiments. Capillary electrophoresis and peptide mapping after enzymatic digestion supply complementary information on charge variants and modification sites. Circular dichroism and nuclear magnetic resonance can report on secondary structure in solution. Absolute quantification usually depends on an external standard, and reported purity depends on the detection wavelength and integration parameters chosen.
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.
| Property | Value | Notes |
|---|---|---|
| Purity assessment | RP-HPLC, 214 nm | Wavelength affects relative peak areas |
| Identity confirmation | LC-MS/MS | Precursor and fragment ion masses compared |
| Common degradation | Deamidation, oxidation | Amide and methionine residues are main sites |
| Working solution storage | 2-8 °C, short term | Longer holding favours frozen aliquots |
| Adsorption risk | Higher below 1 mg/mL | Glass and plastic surfaces both affected |
Semaglutide 是一种经结构修饰的胰高血糖素样肽-1 类似物，其主链与内源性 GLP-1(7-36) 约有百分之九十四的序列一致性。第 8 位丙氨酸被 α-氨基异丁酸取代，使二肽基肽酶-4 无法识别原有切割位点。第 34 位赖氨酸换为精氨酸，进一步降低酶解速率。第 26 位赖氨酸经间隔基连接一条含十八个碳的二酸脂肪链，该侧链赋予分子与血浆白蛋白结合的能力。
该分子作为 GLP-1 受体的选择性激动剂发挥作用，受体属于 B 类 G 蛋白偶联受体家族，激活后经 Gs 通路提升细胞内环腺苷酸水平。在胰腺 β 细胞，信号促进葡萄糖依赖性的胰岛素释放，血糖偏低时该作用明显减弱。在胰岛 α 细胞，胰高血糖素分泌受到抑制。中枢神经系统与胃肠道同样存在受体表达，相应信号参与食欲调节以及胃排空速率的降低。
皮下注射后吸收相对缓慢，绝对生物利用度约为百分之八十九，血药浓度峰值通常出现在给药后一到三天。与白蛋白结合使清除减慢，终末半衰期约为一百六十五小时，接近一周。连续给药约四到五周后达到稳态暴露水平。表观分布容积约为每千克零点二五升，血浆蛋白结合率超过百分之九十九。代谢以蛋白水解切割和脂肪二酸侧链的 β-氧化为主，相关产物主要经尿液与粪便排出。
Quality control for peptide material focuses on identity, purity, content and the profile of impurities. Common degradants include deamidated and oxidised forms, plus aggregates formed during storage or handling. Forced degradation studies under heat, light, acid and peroxide help define which conditions accelerate change and which analytical methods detect it. Limits for individual impurities are set by pharmacopoeial monographs or manufacturer specifications. How much a given impurity affects biological activity is often uncertain, and conclusions may depend on the assay used.
Solid peptide material is generally kept at reduced temperature to limit degradation. Short-term storage at 2 to 8 degrees Celsius is common, while longer archival storage at minus 20 degrees Celsius or below is typical for lyophilised powder. Vials should remain sealed and protected from light, because ultraviolet exposure can oxidise susceptible residues. Repeated freeze-thaw cycles are avoided, as they promote aggregation and loss of soluble material. Solutions are less stable than solids and are usually prepared close to the time of use.
Reversed-phase high-performance liquid chromatography is widely used to assess purity and to separate the parent peptide from related substances. Mass spectrometry confirms identity and can resolve modifications that differ by a few daltons. Size-exclusion chromatography detects dimers and higher aggregates, which are relevant to both stability and immunogenicity questions. Peptide mapping with enzymatic digestion locates specific modifications along the sequence. Circular dichroism provides a secondary-structure profile, although it gives limited information about local conformational changes.
Receptor binding triggers G protein signaling that raises intracellular cyclic AMP in pancreatic beta cells. Insulin release follows in a glucose-dependent manner, so secretion increases when blood glucose is elevated and diminishes when it is not. The same signaling suppresses glucagon release from alpha cells and slows gastric emptying, which blunts the post-meal glucose rise. In the brain, receptor activation in regions such as the arcuate nucleus is associated with reduced appetite and lower energy intake. How much each of these effects contributes to overall weight change is not fully settled.
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
In China nearly all universities and research institutions are public. Typically, provincial governments run public universities. However, some are administered by municipal governments or are national, which the central government directly administers. Private undergraduate colleges exist but are primarily vocational colleges sponsored by private entities. Private universities can award bachelor's degrees. Public universities tend to enjoy a higher reputation domestically and globally.
== Applications == Peroxidase can be used for treatment of industrial waste waters. For example, phenols, which are important pollutants, can be removed by enzyme-catalyzed polymerization using horseradish peroxidase. Thus phenols are oxidized to phenoxy radicals, which participate in reactions where polymers and oligomers are produced that are less toxic than phenols. It also can be used to convert toxic materials into less harmful substances. There are many investigations about the use of peroxidase in many manufacturing processes like adhesives, computer chips, car parts, and linings of drums and cans. Other studies have shown that peroxidases may be used successfully to polymerize anilines and phenols in organic solvent matrices. Peroxidases are sometimes used as histological markers. Cytochrome c peroxidase is used as a soluble, easily purified model for cytochrome c oxidase.
During the course of the symposium a semantic difficulty became apparent. To some of the participants, "microsomes" mean the ribonucleoprotein particles of the microsome fraction contaminated by other protein and lipid material; to others, the microsomes consist of protein and lipid contaminated by particles. The phrase "microsomal particles" does not seem adequate, and "ribonucleoprotein particles of the microsome fraction" is much too awkward. During the meeting, the word "ribosome" was suggested, which has a very satisfactory name and a pleasant sound. The present confusion would be eliminated if "ribosome" were adopted to designate ribonucleoprotein particles in sizes ranging from 35 to 100S. Albert Claude, Christian de Duve, and George Emil Palade were jointly awarded the Nobel Prize in Physiology or Medicine, in 1974, for the discovery of the ribosome. The Nobel Prize in Chemistry 2009 was awarded to Venkatraman Ramakrishnan, Thomas A. Steitz, and Ada E. Yonath for determining the detailed structure and mechanism of the ribosome.
Sources: en.wikipedia.org
By inhibiting this pathway, less collagen was produced and deposited in the heart, preventing the formation of cardiac fibrosis. Huang and Chen (2013) claim that oxymatrine may even be involved in inhibiting the expression of TGF-β1 receptors, which would further support that oxymatrine attenuates the signal transduction pathway involved in collagen production. They also reported that inhibition of the TGF-β1 receptor may also prevent ventricular remodeling.
Lewis Clayton Cantley (born February 20, 1949) is an American cell biologist and biochemist who has made significant advances to the understanding of cancer metabolism. Among his most notable contributions are the discovery and study of the enzyme PI-3-kinase, now known to be important to understanding cancer and diabetes mellitus. He was Meyer Director and Professor of Cancer Biology at the Sandra and Edward Meyer Cancer Center at Weill Cornell Medicine in New York City. He is a professor in the Departments of Systems Biology and Medicine at Harvard Medical School, and the Director of Cancer Research at the Beth Israel Deaconess Medical Center, in Boston, Massachusetts. In 2016, he was elected Chairman of the Board for the Hope Funds for Cancer Research.
== Legal == Anti-doping policies instituted by individual sporting governing bodies may conflict with local laws. A notable case includes the National Football League (NFL)'s inability to suspend players found with banned substances, after it was ruled by a federal court that local labor laws superseded the NFL's anti-doping regime. The challenge was supported by the National Football League Players Association. Athletes caught doping may be subject to penalties from their local, as well from the individual sporting, governing body. The legal status of anabolic steroids varies from country to country. Fighters found using performance-enhancing drugs in mixed martial arts competitions (e.g. the UFC) could face civil and/or criminal charges once Bill S-209 passes. Under certain circumstances, when athletes need to take a prohibited substance to treat a medical condition, therapeutic use exemptions may be granted.
According to CTV News Queen's Park Bureau Chief, Colin D'Mello, Premier Ford removed Fedeli as Finance Minister on June 20, 2019 in the "wake of a disastrous budget rollout that's left the Progressive Conservative government drowning in negative publicity." Minister Fedeli tabled the Ford government's first budget on April 11, 2019. According to the Sault Star, Fedeli was demoted from "highly-touted finance post" and "blamed" for the "failure to sell voters on the $163.4-billion budget and the cost of breaking a 10-year deal that ultimately expands beer and wine sales in grocery stores, costing taxpayers $1 billion." NDP Timiskaming-Cochrane MPP, John Vanthof, said that the 2019 budget failed northern Ontario by not providing funds for Highway 69, the Ring of Fire, expanded broadband access, and cuts to Indigenous Affairs, Ministry of Natural Resources, the Ministry of Agriculture, Food, and Rural Affairs, and more. Vanthof said that there "will be beer in corner stores, drinks at 9 in the morning, tailgate parties, and blue licence plates, but when the fog is cleared, there is also an over $500 million cut to the Ministry of Northern Development and Mines." In the fiscal year 2019, the publicly funded Legal Aid Ontario will receive $133 million less than previously, representing a funding cut of 30 per cent, as part of the Ford government's deficit-cutting plan, presented in the April 2019 budget.
Sources: en.wikipedia.org
Herringbone stitch secures the edges of a textile to a backing fabric. This stitch is also a flexible way to join more than one layer of fabric. Herrigbone stitch is similar to a cross stitch with interlocking stitches. Slip-stitch is used to secure a backing fabric and is nearly invisible on the right side of the fabric. Couching is the most commonly used stitching method in textile stabilization. Torn, frayed, or weak areas can be secured to a support fabric with couching. Generally, a 5mm stitch spacing will give stability and be quicker to stitch than a closer spacing. Darning stitch is used to cover areas of loss and prevent further degradation. Laid couching is a long straight stitch, held in place with short perpendicular stitches. Brick couching is a short stitch placed over one or several threads and sewn in a brick-work like pattern. Thread types cotton thread is the most commonly used thread for stabilizing textiles. Fine polyester is also acceptable.
In an interview with The Independent, Joon-ho said that he did not "expect the entire audience to convert to veganism after watching the film" and said that he does not have an issue with meat consumption, but asked the audience to consider where their food comes from, and said if that happens, then the "level of meat consumption will gradually decline." Joon-Ho told LA Times that in his view, the food industry is "always trying to do is try to thicken the walls of the slaughterhouse so that nobody can peer inside it," with LA Times noting that Joon-Ho became vegan after visiting a slaughterhouse in South Korea, but ended the diet change after two months. Paul Dano, who plays Jay in the film, also told GQ that, while he is a meat-eater, it made him want to "be more conscientious consumer" and said it is easy to "forget that when we put our dollar down we are supporting something." Other scholars noted vegetarian themes in the films The Fault in Our Stars, The Princess Diaries series, and the 2009 film, Vegetarian.
In the 2010s, Ells tried to diversify the company by creating or acquiring several subsidiaries. These subsidiaries offered very different cuisines compared to their parent company. Examples include soul food (Soul Daddy), Asian cuisine (ShopHouse Southeast Asian Kitchen), pizza (Pizzeria Locale), and burgers (Tasty Made). In 2023, Chipotle had also tried incorporating California-inspired bowls into the Farmesa Fresh Eatery concept. The few test locations were not a financial success, and all concepts were discontinued. In 2011, Steve Ells was a judge for the TV show America's Next Great Restaurant and investor of ANGR Holdings, the company that would launch the winning concept's restaurants. Chipotle agreed to purchase Ells' investment in ANGR at his cost, provide support for ANGR operations, and invest a total of $2.3 million in cash contributions. The winning concept, Soul Daddy, was quickly closed after operating for eight weeks. In September 2011, Chipotle opened an Asian fast-casual concept restaurant named ShopHouse Southeast Asian Kitchen in Washington, D.C. The company said the new restaurant "would follow the Chipotle service format and its focus on 'food with integrity' in ingredients". Chipotle's plan was to start with only one store and see how the restaurant worked out before expanding the concept. On July 29, 2016, the company announced the opening of its first Tasty Made burger restaurant in the fall.
=== Usage === A survey conducted in late 2009 by the National Addiction Centre (UK) found 41.3% of readers of Mixmag had used mephedrone in the last month, making it the fourth-most popular drug amongst clubbers. Of those, two-thirds snorted the drug and the average dosage per session was 0.9 g; the length of sessions increased as the dosage increased. Users who snorted the drug reported using more per session than those who took it orally (0.97 g compared to 0.74 g) and also reported using it more often (five days per month compared to three days per month). An Irish study of people on a methadone treatment program for heroin addicts found 29 of 209 patients tested positive for mephedrone usage.
Aldo Carl Leopold (December 18, 1919 – November 18, 2009) was an American academic and plant physiologist, son of Aldo Leopold, a noted ecologist. He is known for his research on soybeans which led to techniques allowing insulin to be dried and later processed into an inhalable insulin. Aldo Carl Leopold was born to Aldo Leopold, a noted ecologist and employee of the United States Forest Service, and Estella Leopold in Albuquerque, New Mexico as the 4th of 5 children.
Sources: en.wikipedia.org
Filtering removes particulate matter that can block columns or scatter light. A 0.22 micrometre membrane is typical, and the filter material should be checked for peptide adsorption.
Peptides can bind to glass and plastic, so a fraction of the material leaves the solution. The effect is proportionally larger in dilute samples and can bias quantitative results.
Reverse-phase high-performance liquid chromatography is the most widely reported approach. Purity figures should always be quoted together with the wavelength, gradient, and integration parameters used.
It is a synthetic analog of GLP-1 produced through medicinal chemistry to resist enzymatic degradation. The design goal was longer circulation than the native hormone.