This is a working overview of incretin hormone, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-01-06. Anything still debated is marked as such rather than presented as settled.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
Serum protein binding dominates the pharmacokinetic profile. The attached chain associates strongly with albumin, shielding the peptide from enzymatic attack and slowing filtration by the kidney. This interaction extends the circulation half-life to roughly one week in humans, which supports weekly administration intervals. An oral version pairs the peptide with an absorption enhancer that transiently alters gastric epithelium, permitting limited uptake; bioavailability by that route is substantially lower than by injection.
Semaglutide belongs to the glucagon-like peptide-1 receptor agonist class, a group of synthetic peptides that imitate an incretin hormone released by intestinal L cells after food intake. Native GLP-1 circulates for only a few minutes because dipeptidyl peptidase-4 cleaves it rapidly. The hormone acts on pancreatic islets, the gastrointestinal tract, and several brain regions. Because the natural peptide is short-lived, development work concentrated on analogues that keep receptor activity while resisting enzymatic breakdown and renal clearance.
The semaglutide sequence is a 31-residue analogue of human GLP-1, altered at three positions relative to the parent hormone. Aminoisobutyric acid replaces alanine at position 8, arginine replaces lysine at position 34, and a lipophilic diacid is attached to lysine 26 through a short linker. These features are reported consistently in the structural literature. The position 8 substitution blocks recognition by dipeptidyl peptidase-4, while the attached chain drives strong, reversible association with a carrier protein in blood.
| Property | Value | Notes |
|---|---|---|
| Molecular class | 31-amino-acid peptide | Modified glucagon-like peptide-1 analogue |
| Molecular mass | approximately 4114 Da | Calculated for the free peptide backbone |
| Appearance | white to off-white powder | Typical of purified lyophilised peptide batches |
| Solubility class | freely soluble in water | Aqueous solubility improves at slightly alkaline pH |
| Typical storage | -20 degrees Celsius, dry, dark | Protect from repeated freeze-thaw cycles |
Reverse-phase high-performance liquid chromatography is the standard method for purity assessment, separating the peptide from truncated or oxidized variants. Mass spectrometry confirms molecular mass and detects modifications, while ultraviolet absorbance near 280 nanometers supports concentration measurement through tryptophan and tyrosine residues. Circular dichroism can indicate secondary structure, though the peptide is largely helical in solution, and ion-exchange chromatography resolves charge variants. Purity values above 95 percent are typical for research-grade material. Stability studies track degradation over time under defined conditions.
Lyophilized semaglutide is typically stored at temperatures between minus 20 and minus 80 degrees Celsius for long-term preservation. Short-term storage at 2 to 8 degrees Celsius is common for working aliquots. Repeated freeze-thaw cycles can degrade the peptide and are usually avoided. The molecule is hygroscopic in its solid form, so containers should remain sealed with desiccant. Solutions are less stable than powders and are generally prepared fresh. Light exposure is limited because aromatic residues can undergo photo-oxidation.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1, a hormone released from intestinal L cells after food intake. The molecule is a 31-amino-acid backbone modified at three positions to resist cleavage by dipeptidyl peptidase-4, the enzyme that degrades native GLP-1 within minutes. A lysine residue at position 26 carries a linker and a C18 fatty diacid, which promotes binding to serum albumin and slows renal clearance. These changes extend the circulating half-life from roughly two minutes to about one week in humans.
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.
Three structural changes define the molecule. At position 8 an alpha-aminoisobutyric acid residue replaces alanine, which blocks dipeptidyl peptidase-4 cleavage. At position 34 arginine replaces lysine, and at position 26 a lysine carries a C18 fatty diacid attached through a short linker. The fatty chain binds serum albumin, and this albumin association reduces renal filtration and enzymatic attack. The unchanged backbone retains the receptor contacts that produce signalling. The free base has the formula C187H291N45O59 and a molecular weight near 4114 daltons.
Receptor activation follows the canonical Gs pathway: binding increases intracellular cyclic AMP, which promotes protein kinase A activity. In pancreatic beta cells this amplifies glucose-dependent insulin release, so secretion rises when blood glucose is high and changes little when it is low. The same signalling suppresses glucagon release from alpha cells and slows gastric emptying. Receptors in the hypothalamus and brainstem are thought to contribute to reduced appetite and lower energy intake. Which of these effects dominates clinical outcomes remains an area of active study.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released by intestinal L cells after food intake. The natural hormone acts on pancreatic and central receptors but is degraded within minutes by dipeptidyl peptidase-4 and other peptidases. Semaglutide belongs to the class of long-acting GLP-1 receptor agonists, a group distinguished by structural changes that slow breakdown and extend circulation time. Its development followed earlier short-acting analogues and reflects a general strategy in peptide drug design: preserve receptor activity while blocking proteolytic clearance.
In the early 20th century, taxidermy was taken forward under the leadership of artists such as Carl Akeley, James L. Clark, William T. Hornaday, Coleman Jonas, Fredrick, and William Kaempfer, and Leon Pray. These and other taxidermists developed anatomically accurate figures which incorporated every detail in artistically interesting poses, with mounts in realistic settings and poses that were considered more appropriate for the species. This was quite a change from the caricatures popularly offered as hunting trophies. Additional modern uses of taxidermy have been the use of "faux taxidermy" or fake animal heads that draw on the inspiration of traditional taxidermy. Decorating with sculpted fake animal heads that are painted in different colors has become a popular trend in interior design.
=== Euthanasia === Sodium thiopental is used intravenously for the purposes of euthanasia. In both Belgium and the Netherlands, where active euthanasia is allowed by law, the standard protocol recommends sodium thiopental as the ideal agent to induce coma, followed by pancuronium bromide to paralyze muscles and stop breathing. Intravenous administration is the most reliable and rapid way to accomplish euthanasia. Death is quick. A coma is first induced by intravenous administration of 20 mg/kg thiopental sodium (Nesdonal) in a small volume (10 mL physiological saline). Then, a triple dose of a non-depolarizing neuromuscular blocking drug is given, such as 20 mg pancuronium bromide (Pavulon) or 20 mg vecuronium bromide (Norcuron). The paralytic should be given intravenously to ensure optimal bioavailability but pancuronium bromide may be administered intramuscularly at an increased dosage level of 40 mg.
== Family and personal life == Dan Ariely was born to Yoram and Dafna Ariely in New York City while his father was studying for an MBA at Columbia University. He has two younger sisters. The family emigrated to Israel when he was three years old. He grew up in Ramat Hasharon. In his senior year of high school, Ariely was active in Hanoar Haoved Vehalomed, an Israeli youth movement affiliated with the Labor Zionist movement. While he was preparing a ktovet esh (fire inscription) for a traditional nighttime ceremony, the flammable materials he was mixing exploded, causing third-degree burns to over 70 percent of his body. In his writings entitled "Painful Lessons", Ariely described his hospitalization and treatments, detailing how that experience led to his research on "how to better deliver painful and unavoidable treatments to patients". Ariely was previously married to Sumedha (Sumi) Gupta in 1998; they have two children. After a second manuscript of his was retracted for containing fabricated data, it was reported that Ariely is seeking political office under the banner of the Pirate Party of Israel.
== Research and pipeline == In 2025, Novo tested whether semaglutide helped slow progression for Alzheimer's disease. However, on November 24, 2025, the company announced that the studies failed to find any effect of the drug on cognition and functioning in people with mild cognitive impairment or with dementia. Novo was researching pulmonary delivery systems for diabetic medications, and in the early stages of research into autoimmune and chronic inflammatory diseases, using technologies such as translational immunology and monoclonal antibodies. In September 2014, the company announced a decision to discontinue all research in inflammatory disorders, including the discontinuation of R&D in anti-IL-20 for the treatment of rheumatoid arthritis. In September 2018, it was reported that the company would lay off 400 administrative staff, laboratory technicians and scientists, in Denmark and China in order to concentrate research and development efforts on "transformational biological and technological innovation".
== E == efficacy – empirical – encephalitis – end-stage disease – endemic – endogenous – endoscopy – endotoxin – endpoint – enteric – enteritis – entry inhibitors – Env – envelope – enzyme – enzyme-linked immunosorbent assay (ELISA) – eosinophil – eosinophilic folliculitis – epidemic – epidemiological surveillance – epidemiology – epithelium – epitope – Epstein-Barr virus (EBV) – erythema – erythema multiforme – erythrocytes – etiology – exogenous – exotoxin – expanded access – experimental drug – expression system
Sources: en.wikipedia.org
=== Eclampsia === Magnesium sulfate is effective in decreasing the risk that pre-eclampsia progresses to eclampsia. Intravenous magnesium sulfate is used to prevent and treat seizures of eclampsia. It reduces the systolic blood pressure but does not alter the diastolic blood pressure, so the blood perfusion to the fetus is not compromised. It is also commonly used for eclampsia where compared to diazepam or phenytoin it results in better outcomes.
The cause of capsular contracture is unknown, but the common incidence factors include bacterial contamination, device-shell rupture, filler leakage, and hematoma. The surgical implantation procedures that have reduced the incidence of capsular contracture include submuscular emplacement, the use of breast implants with a textured surface (polyurethane-coated); limited pre-operative handling of the implants, limited contact with the chest skin of the implant pocket before the emplacement of the breast implant, and irrigation of the recipient site with triple-antibiotic solutions. The correction of capsular contracture might require an open capsulotomy (surgical release) of the collagen-fiber capsule, or the removal, and possible replacement, of the breast implant. Furthermore, in treating capsular contracture, the closed capsulotomy (disruption via external manipulation) once was a common maneuver for treating hard capsules, but now is a discouraged technique, because it can rupture the breast implant. Non-surgical treatments for collagen-fiber capsules include massage, external ultrasonic therapy, leukotriene pathway inhibitors such as zafirlukast (Accolate) or montelukast (Singulair), and pulsed electromagnetic field therapy (PEMFT).
Deborah Ann Dingell ( DING-gəl; née Insley; November 23, 1953) is an American politician serving as a U.S. representative from Michigan since 2015, representing the state's 6th congressional district since 2023. A member of the Democratic Party, she succeeded her late husband, John Dingell, who was the longest-serving member of Congress in U.S. history. Dingell is active in several organizations in Michigan and Washington, D.C., and serves on a number of boards. She is a founder and past chair of the National Women's Health Resource Center and the Children's Inn at the National Institutes of Health (NIH). She is also a member of the board of directors for Vital Voices Global Partnership. She is a 1975 graduate of the Edmund A. Walsh School of Foreign Service at Georgetown University. She worked as a consultant to the American Automobile Policy Council. She was a superdelegate for the 2012 Democratic National Convention in Charlotte, North Carolina.
With a triple on May 7, 2001, against Chicago, Bagwell achieved the 700th extra base hit of his career. For the second time in his career, he reached seven RBI in a game — again tying a club record — at Kansas City on July 7. Over four successive games from July 8–13, Bagwell homered and totaled five home runs in that span. In a contest at Enron Field against the St. Louis Cardinals on July 18, he hit for the cycle. He went 4-for-5 with five RBI as the Astros won, 17–11. He was the NL Player of the Month that July after batting .333 with nine home runs, and breaking his own club record with 36 RBI in a month, exceeding the 34 RBI in the previous August. While hitting his 32nd home run on August 19, 2001, against Pittsburgh, Bagwell collected his 100th RBI. It was the sixth consecutive season he reached at least 30 home runs and 100 RBI, making him the eighth player in MLB history to achieve such a streak, and the only Houston player to do so. Five days later, also against Pittsburgh, he scored his 100th run, joining Jimmie Foxx, Lou Gehrig, and Babe Ruth as the only players in MLB history with six consecutive seasons of 30 homers, 100 RBI and 100 runs scored. On September 30 at Chicago, Bagwell walked for his 100th of the season, thus making him the only player in MLB history to register six consecutive seasons of at least 30 home runs, 100 RBI, 100 runs scored, and 100 walks. The Astros won the NL Central division title and faced the Atlanta Braves in the NLDS.
== Effects on weather patterns == El Niño affects the global climate and disrupts normal weather patterns, which can lead to intense storms in some places and droughts in others. In June 2026, the UN warned that El Niño could become one of the strongest in decades, bringing extreme weather such as droughts, floods, storms and raising the chances of wildfires.
Sources: en.wikipedia.org
A nuclear isomer is a metastable state of an atomic nucleus in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have half-lives of 10−9 seconds or longer, 100 to 1000 times longer than the half-lives of the excited nuclear states that decay with a "prompt" half-life (ordinarily on the order of 10−12 seconds). Some references recommend using a threshold of 5×10−9 seconds to distinguish the metastable half-life from the normal "prompt" gamma-emission half-life. The half-lives of a number of isomers are far longer than this and may be minutes, hours, or years. The most extreme example known is the 180m73Ta nuclear isomer, which survives so long (at least 2.9×1017 years) that it has never been observed to decay spontaneously, and occurs naturally as a primordial nuclide, though uncommonly at only 1/8000 of all tantalum. The second most stable isomer is 210m83Bi, which does not occur naturally; its half-life is 3.04×106 years to alpha decay. The half-life of a nuclear isomer can exceed that of the ground state of the same nuclide, as with the two above, as well as, for example, 186m75Re, 192m277Ir, 212m84Po, 242m95Am and multiple holmium isomers.
Severe renal impairment (estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m2) Known hypersensitivity to metformin Acute or chronic metabolic acidosis, including diabetic ketoacidosis (from uncontrolled diabetes), with or without coma
Nicotine was originally isolated from the tobacco plant in 1828 by chemists Wilhelm Heinrich Posselt and Karl Ludwig Reimann from Germany, who believed it was a poison. Its chemical empirical formula was described by Melsens in 1843, its structure was discovered by Adolf Pinner and Richard Wolffenstein in 1893, and it was first synthesized by Amé Pictet and A. Rotschy in 1904. Nicotine is named after the tobacco plant Nicotiana tabacum, which in turn is named after the French ambassador in Portugal, Jean Nicot de Villemain, who sent tobacco and seeds to Paris in 1560, presented to the French King, and who promoted their medicinal use. Smoking was believed to protect against illness, particularly the plague. However, the "holy herb", tobacco, had first reached Europe by the early 1530s, brought by Spanish explorers. Following its introduction, tobacco rapidly gained popularity in Europe for its stimulating effects, fueled by nicotine's addictive and pharmacological properties and tobacco's widespread embrace as a cure-all. By the early 17th century, this allure fueled its mercilessly laborious cultivation as a cash crop in the Virginia colonies, where John Rolfe's introduction in 1612 rescued Jamestown from economic collapse and famine, transforming it into a prosperous export hub with over 20,000 pounds shipped by 1619 and laying the groundwork for transatlantic trade.
=== General and cited references === Carnegie Library of Pittsburgh. Science and Technology Department. The Handy Science Answer Book. Pittsburgh: The Carnegie Library, 1997. ISBN 978-0-7876-1013-5. Perham, Nick; Moore, Simon C.; Shepherd, Jonathan; Cusens, Bryany (2007). "Identifying drunkenness in the night-time economy". Addiction. 102 (3): 377–80. doi:10.1111/j.1360-0443.2006.01699.x. PMID 17298644. Taylor, L., and S. Oberman. Drunk Driving Defense, 6th edition. New York: Aspen Law and Business, 2006. ISBN 978-0-7355-5429-0.
=== Other dipeptides === Homoanserine (N-(4-aminobutyryl)-L-histidine) is another dipeptide identified in the brain and muscles of mammals. Kyotorphin (L-tyrosyl-L-arginine) is a neuroactive dipeptide which plays a role in pain regulation in the brain. Balenine (or ophidine) (beta-alanyl-N tau-methyl histidine) has been identified in the muscles of several species of mammal (including man), and the chicken. Glorin (N-propionyl-γ-L-glutamyl-L-ornithine-δ-lac ethyl ester) is a chemotactic dipeptide for the slime mold Polysphondylium violaceum. Barettin (cyclo-[(6-bromo-8-en-tryptophan)-arginine]) is a cyclic dipeptide from the marine sponge Geodia barretti. Dialanine is commonly used as a model in molecular dynamics. Xenortides, isolated from the bacterium Xenorhabdus nematophila Oglufanide (H-L-Glu-Trp-OH, also known as Thymogen), immunomodulator researched for conditions including Hepatitis C.
Sources: en.wikipedia.org
It is a glucagon-like peptide-1 receptor agonist, often grouped with the incretin mimetics. Its backbone is modified from the human hormone to resist enzymatic degradation and to bind albumin. These two features distinguish it from the native peptide.
No. It shares high sequence identity but carries non-natural modifications that alter its stability and clearance. The naturally occurring hormone is broken down within minutes, while the synthetic analogue circulates far longer.
Attachment to serum albumin reduces renal filtration of the peptide and shields it from enzymatic breakdown. The consequence is a much longer interval between administrations than unmodified peptides allow. The precise contribution of binding affinity to overall duration is still being quantified.
It is a synthetic peptide of 31 amino acids, built to resemble the natural incretin hormone GLP-1. Because of its size and composition it is handled analytically like other therapeutic peptides, using chromatographic and mass spectrometric methods rather than the techniques typical of small organic drugs.