If you have been reading about 二肽基肽酶-4 and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Activation of the GLP-1 receptor couples to Gs signalling and raises intracellular cyclic AMP in pancreatic beta cells. The resulting insulin release depends on prevailing glucose concentrations, so the effect is greater when glucose is elevated. Receptor engagement also suppresses glucagon secretion and slows gastric emptying, which flattens post-meal glucose excursions. In the central nervous system, signalling in hypothalamic and brainstem regions is associated with reduced appetite and lower energy intake. Studies continue to examine effects on cardiac, renal and hepatic endpoints; whether those benefits are independent of weight change remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | Parent peptide; salt forms also reported |
| Molecular mass | about 4113.6 Da | Average mass of the free peptide |
| Peptide length | 31 amino acids | Backbone related to GLP-1(7-37) |
| Key substitution | Aib at position 8 | Blocks DPP-4 cleavage |
| Albumin binding | Via C-18 diacid side chain | Prolongs circulation time |
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。
序列层面的改动同时解决了两个问题，即酶解稳定性与肾脏清除速度。天然 GLP-1 在循环中的半衰期仅约两分钟，主要被二肽基肽酶-4 迅速灭活。酰化侧链与白蛋白的可逆结合形成循环储库，使分子缓慢释放并持续激活受体。这种设计思路后来被广泛用于同类长效肽的开发，属于该类药物化学改造的典型范式。
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.
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.
=== Investigations === Several sets of investigations, both congressional via the Senate Armed Services Committee, military via courts-martial, and criminal for non-military contractors, were launched in response to the scandal. Seymour Hersh, who exposed the Abu Ghraib scandal, and reports in Newsweek, has taken the case even further. In 2003, Donald Rumsfeld instituted a policy that "encouraged physical coercion and sexual humiliation of Iraqi prisoners in an effort to generate more intelligence about the growing insurgency in Iraq.". This policy stemmed from an earlier policy taken toward al-Qaeda prisoners. A memo to the Bush White House from counsel Alberto Gonzales claimed that the new sort of war renders the Geneva Conventions' limitations on interrogating enemy prisoners "obsolete". The program was approved by the CIA, NSA, and the National Security Council. President George W. Bush was informed of it. The Under Secretary of Defense for Intelligence Steven Cambone administered the operation. His deputy, William Boykin, instructed the head of operations at Camp X-ray Maj. Gen. Geoffrey Miller to do the same at Abu Ghraib. Miller told Brig. Gen. Janis Karpinski that the prison would now be dedicated to gathering intelligence. Douglas Feith and William Haynes were also involved in the operation. On May 18, 2004, a military intelligence analyst named Samuel Provance came out to the press, stating "There's definitely a cover-up".
Juice is prepared by mechanically squeezing or macerating (sometimes referred to as cold pressing) fruit or vegetable flesh without the application of heat or solvents. For example, orange juice is the liquid extract of the fruit of the orange tree, and tomato juice is the liquid that results from pressing the fruit of the tomato plant. Juice may be prepared at home from fresh fruit and vegetables using a variety of hand or electric juicers. Many commercial juices are filtered to remove fiber or pulp, but high-pulp fresh orange juice is a popular beverage. Additives are put in some juices, such as sugar and artificial flavours (in some fruit juice-based beverages) or savoury seasonings (e.g., in Clamato or Caesar tomato juice drinks). Common methods for the preservation and processing of fruit juices include canning, pasteurization, concentrating, freezing, evaporation, and spray drying. Although processing methods vary between juices, the general processing method of juices includes:
Hegseth refuses to rule out US military force against it. Syria is removed by the US Department of State from its State Sponsors of Terrorism list. Nearly 90,000 people are told to evacuate as a wildfire approaches Reno, Nevada. August 25 Ghislaine Maxwell loses her attempt to overturn her sex trafficking conviction. US officials corroborate Trump's claim that the US Navy cleared mines from the Strait of Hormuz Traffic Separation Scheme, saying underwater drones identified more than 100 suspected mines that were subsequently removed or detonated by contractors. Trump says the US will destroy Iranian vessels that lay further mines. Secretary of State Marco Rubio tells allies that the US is not expected to resume major combat operations against Iran "for the time being", with another US official saying this policy is likely to continue until after the midterm elections. August 26 Meta agrees to a $17.1 billion settlement over claims brought by 29 states that its platforms harm children. Palestine Action is designated by the US as a terrorist organization. The FDA approves the new daraxonrasib drug by Revolution Medicines to treat pancreatic cancer. Studies and testing found that patients taking the drug nearly doubled their survival time with fewer side effects. SpaceX and Louisiana governor Jeff Landry co-announce a plan to build a $100 billion spaceport on 125,000 acres (51,000 ha) of land in Vermilion Parish. The US military schedules a trial date for the suspected 9/11 mastermind Khalid Sheik Mohammed in 2028.
== Details == The Japanese version included the song "Lost On The Moon" as a bonus track, while a special tour version was released in 2004 with a bonus disc, which included live versions of "Barely Breathing" and "Half-Life", alternate versions of "Bite Your Tongue" and "On a High", and a remix of "Reasons For Living". "Half-Life" was also featured in the 2003 film What a Girl Wants.
Sources: en.wikipedia.org
There are several causes of hyperthyroidism. Most often, the entire gland is overproducing thyroid hormone. Less commonly, a single nodule is responsible for the excess hormone secretion, called a "hot" nodule. Thyroiditis (inflammation of the thyroid) can also cause hyperthyroidism. Functional thyroid tissue producing an excess of thyroid hormone occurs in a number of clinical conditions. The major causes in humans are:
The enzyme converts the precursor (6R)-2-acetyl-6-(3-acetyl-2,4,6-trihydroxy-5-methylphenyl)-3-hydroxy-6-methylcyclohexa-2,4-dien-1-one into (S)-usnic acid using oxidised nicotinamide adenine dinucleotide (NAD+) as cofactor and forming an ether bond. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is reduced-(S)-usnate:NAD+ oxidoreductase (ether-bond-forming). This enzyme is also called L-usnic acid dehydrogenase.
== Research == As of August 2025, KNX-100 is in phase 2 clinical trials for treatment of agitation and aggression in dementia, phase 1 trials for opioid-related disorders and substance-related disorders, and the preclinical research stage of development for behavioral disorders. Phase 1 trials were first planned for 2019. Several clinical trials of KNX-100 have been registered with details provided. In addition to the preceding indications, there is also interest in KNX-100 for other potential applications like treatment of social anxiety, other types of addiction besides substance addiction like gambling, and pain, among others. Besides KNX-100, Kinoxis Therapeutics also has selective oxytocin receptor partial agonists like its KNX-200 series and oxytocin receptor positive allosteric modulators like its KNX-300/400 series in its developmental pipeline.
Sources: en.wikipedia.org
It belongs to the incretin mimetic class and acts as a long-acting glucagon-like peptide-1 receptor agonist. The class includes several peptides with different half-lives and routes of administration.
The side chain enables reversible binding to albumin in the bloodstream, which protects the peptide from rapid renal clearance. This extends the interval between administrations compared with unmodified GLP-1.
No. It shares much of the native sequence but carries substitutions and an added side chain. These changes increase stability against enzymatic breakdown.
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.