This is a working overview of incretin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-18 and is reviewed periodically as new material appears.
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.
Development began in the early 2010s with the goal of extending GLP-1 activity beyond the brief window achieved by native peptide infusion. The earliest approved formulation was a subcutaneous injection given once weekly. A later oral tablet pairs the peptide with an absorption enhancer, sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, usually shortened to SNAC. That carrier lowers local pH and helps the peptide cross gastric tissue. Both routes deliver the same active molecule.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, a gut hormone released after meals. Its backbone retains the GLP-1 sequence but incorporates two substitutions that slow enzymatic breakdown by dipeptidyl peptidase-4. A short polyethylene glycol linker and a C18 fatty diacid are attached to the peptide chain, allowing the molecule to bind serum albumin and remain in circulation far longer than the native hormone. The result is a circulating half-life measured in days rather than the minutes typical of endogenous GLP-1.
Receptor activation occurs at GLP-1 receptors distributed across pancreatic islets, the hypothalamus, and the gastrointestinal tract. Binding triggers G protein signaling that raises cyclic AMP and enhances glucose-dependent insulin release. Because the effect depends on prevailing glucose levels, insulin secretion does not rise when blood sugar is already low. Signaling in the brain and gut also influences appetite and gastric emptying, which is why the compound appears in both metabolic and weight-related research literature.
| 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 |
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.
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.
This refrigeration method cools a contained area by melting ice, by sublimating dry ice, or evaporating liquid nitrogen. A simple example of this is a portable cooler, where ice is poured over the items that need to be refrigerated, keeping them cool and insulated from heat. Regular ice maintains freezing temperatures, but not below the freezing point, unless salt is used to cool the ice down further (as in a traditional ice-cream maker). Mixtures of other solvents with coolants like water ice, dry ice, or liquid nitrogen are also used to make cooling baths for chemistry. Dry ice can reliably bring the temperature well below the freezing point of water, to as low as 195K.
Bokkoms is whole, salted and dried mullet and is a well-known speciality the West Coast region of South Africa. This salted fish is dried in the sun and wind and is eaten after peeling off the skin. In some cases it is also smoked.
==== North Korea ==== The most restrictive internal border controls are in North Korea. Citizens are not allowed to travel outside their areas of residence without explicit authorisation, and access to the capital city, Pyongyang, is heavily restricted. Similar restrictions are imposed on tourists, who are only allowed to leave Pyongyang on government-authorised tours to approved tourist sites.
== See also == First 100 days of the second Trump presidency – Period from January to April 2025 List of executive actions by Donald Trump Lists of presidential trips made by Donald Trump (international trips) Second presidential transition of Donald Trump – Transfer of presidential power from Joe Biden to Donald Trump Timeline of the 2024 United States presidential election
Jean Yee Hwa Yang is an Australian statistician known for her work on variance reduction for microarrays, and for inferring proteins from mass spectrometry data. Yang is a Professor in the School of Mathematics and Statistics at the University of Sydney.
Sources: en.wikipedia.org
== Gameplay == Half-Life Alyx is a first-person shooter played in virtual reality (VR). Players control the Resistance member Alyx Vance, who fights the Combine, an alien empire that has conquered Earth. Like previous Half-Life games, Alyx incorporates combat, puzzles, exploration and narrative. Players use VR to get supplies, use interfaces, throw objects and use weapons. Like the gravity gun from Half-Life 2, the gravity gloves allow players to pick up objects from a distance. By solving hacking puzzles, Alyx can interact with Combine technology. Alyx includes elements of survival horror, with frightening encounters and scarce ammunition. In one chapter, players encounter Jeff, a blind monster attracted to sound, and must move quietly and throw objects to distract him. Alien spores in the area cause Alyx to cough, which players can prevent by holding their hands over their mouths. Alyx supports all VR headsets compatible with SteamVR, including the Valve Index, HTC Vive, Oculus Rift, Meta Quest and all Windows Mixed Reality headsets. As the gameplay was designed for VR, Valve said they had no plans for a non-VR version. Alyx also supports user mods via the Steam Workshop.
Abscisic acid (also called ABA) is one of the most important plant growth inhibitors. It was discovered and researched under two different names, dormin and abscicin II, before its chemical properties were fully known. Once it was determined that the two compounds are the same, it was named abscisic acid. The name refers to the fact that it is found in high concentrations in newly abscissed or freshly fallen leaves. This class of PGR is composed of one chemical compound normally produced in the leaves of plants, originating from chloroplasts, especially when plants are under stress. In general, it acts as an inhibitory chemical compound that affects bud growth, and seed and bud dormancy. It mediates changes within the apical meristem, causing bud dormancy and the alteration of the last set of leaves into protective bud covers. Since it was found in freshly abscissed leaves, it was initially thought to play a role in the processes of natural leaf drop, but further research has disproven this. In plant species from temperate parts of the world, abscisic acid plays a role in leaf and seed dormancy by inhibiting growth, but, as it is dissipated from seeds or buds, growth begins. In other plants, as ABA levels decrease, growth then commences as gibberellin levels increase. Without ABA, buds and seeds would start to grow during warm periods in winter and would be killed when it froze again.
=== Sources === Print Bosco, David (2009). Five to Rule Them All: The UN Security Council and the Making of the Modern World. Oxford University Press. ISBN 978-0-19-532876-9. Dallek, Robert (1995). Franklin D. Roosevelt and American Foreign Policy, 1932–1945: With a New Afterword. Oxford University Press. ISBN 978-0-19-982666-7. Gaddis, John Lewis (1972). The United States and the Origins of the Cold War, 1941–1947. Columbia University Press. ISBN 978-0-231-12239-9. Hoopes, Townsend; Brinkley, Douglas (1997). FDR and the Creation of the U.N.. Yale University Press. ISBN 978-0-300-08553-2. Kimball, Warren F. (1991). The Juggler: Franklin Roosevelt as Wartime Statesman. Princeton University Press. ISBN 0-691-03730-2. Ma, Xiaohua (2003). The Sino-American alliance during World War II and the lifting of the Chinese exclusion acts. New York: Routledge. pp. 203–204. ISBN 0-415-94028-1. United States Department of State (1942). "Union of Soviet Socialist Republics". Foreign relations of the United States diplomatic papers, 1942. Europe Volume III. U.S. Government Printing Office. pp. 406–771. Welles, Sumner (January 1951). "Two Roosevelt Decisions: One Debit, One Credit". Foreign Affairs. Vol. 29, no. 2. pp. 182–204. Online "1942: Declaration of The United Nations". United Nations. Archived from the original on May 13, 2016. Retrieved April 21, 2016. "1945: The San Francisco Conference". United Nations. 1945. Archived from the original on October 30, 2015. Retrieved May 16, 2015. Urquhart, Brian (July 16, 1998). "Looking for the Sheriff". New York Review of Books.
=== Stocking === Research from the late 1800s to the 1980s suggests a trend of intentional stockings of nonindigenous fish into ponds, lakes, and rivers in the United States. At that time, little was known about environmental impacts or long-term effects of new species establishment and spread as a result of "fish rescue and transfer" efforts, or the importance of nongame fish to the ecological balance of aquatic ecosystems. Introductions of bowfin to areas they were considered a nonindigenous species included various lakes, rivers, and drainages in Connecticut, Delaware, Georgia, Illinois, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Virginia, West Virginia, and Wisconsin. Many of the introductions were intentional stockings, positively determining distribution resulting from flood transfers, or other inadvertent migrations is not possible. Bowfin are typically piscivorous, but as an introduced species, they are capable of being voracious predators that pose a threat to native fish and their prey.
== Awards == Vincent du Vigneaud Award for Excellence in Peptide Science (2000) American Chemical Society's Ralph F. Hirschmann Award in Peptide Chemistry (2004) Bruce Merrifield Award (2005) Fellow of the American Association of Pharmaceutical Scientists (2006) Dan K. Richardson Entrepreneurship Program's 2011 Entrepreneur of the Year
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.
Native GLP-1 is degraded within minutes by circulating enzymes. The synthetic version carries substitutions at positions that block enzymatic cleavage, plus a fatty acid side chain that promotes albumin binding. These two changes together extend circulation time from minutes to roughly a week.