GLP-1 类似物 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-02-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
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 |
|---|---|---|
| Chemical class | GLP-1 receptor agonist peptide | Mimics endogenous incretin signaling |
| Molecular mass | Approximately 4114 Da | Modified 31-amino-acid backbone |
| Appearance | White to off-white powder | Typical of lyophilized peptide material |
| Solubility | Soluble in water | Behavior depends on salt form and buffer |
| Elimination half-life | About one week | Supported by albumin binding and protease resistance |
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.
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 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。
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 dissolves readily in water and in aqueous buffers near neutral pH. Solubility decreases near the isoelectric point, where net charge is minimal. Common laboratory solvents include phosphate-buffered saline and dilute ammonium bicarbonate. Strongly acidic or basic conditions may accelerate hydrolysis. Working concentrations are usually prepared by diluting a concentrated stock. Vial surfaces can adsorb small amounts of peptide at low concentrations, so carrier proteins or low-binding tubes are sometimes used.
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.
where SCr is serum creatinine (mg/dL), k is 0.7 for females and 0.9 for males, a is −0.241 for females and −0.302 for males, min indicates the minimum of SCr/k or 1, and max indicates the maximum of SCr/k or 1. As separate equations for different populations: For creatinine (IDMS calibrated) in mg/dL:
If references are made, the Court of Justice will give a preliminary ruling, in order for the member state court to conclude the case and award a remedy. The right to an effective remedy is a general principle of EU law, enshrined in the Charter of Fundamental Rights article 47. Most of the time Regulations and Directives will set out the relevant remedies to be awarded, or they will be construed from the legislation according to the practices of the member state. It could also be that the government is responsible for failure to properly implement a Directive or Regulation, and must therefore pay damages. In Francovich v Italy, the Italian government had failed to set up an insurance fund for employees to claim unpaid wages if their employers had gone insolvent, as the Insolvency Protection Directive required. Francovich, the former employee of a bankrupt Venetian firm, was therefore allowed to claim 6 million Lira from the Italian government in damages for his loss. The Court of Justice held that if a Directive would confer identifiable rights on individuals, and there is a causal link between a member state's violation of EU and a claimant's loss, damages must be paid. The fact that the incompatible law is an Act of Parliament is no defence. So, in Factortame it was irrelevant that Parliament had legislated to require a quota of British ownership of fishing vessels in primary legislation.
Ethologist Jonathan Balcombe stated that female bonobos rub their clitorises together rapidly for ten to twenty seconds, and this behavior, "which may be repeated in rapid succession, is usually accompanied by grinding, shrieking, and clitoral engorgement"; he added that, on average, they engage in this practice "about once every two hours", and as bonobos sometimes mate face-to-face, "evolutionary biologist Marlene Zuk has suggested that the position of the clitoris in bonobos and some other primates has evolved to maximize stimulation during sexual intercourse". Many strepsirrhine species exhibit elongated clitorises that are either fully or partially tunneled by the urethra, including mouse lemurs, dwarf lemurs, all Eulemur species, lorises and galagos. Some of these species also exhibit a membrane seal across the vagina that closes the vaginal opening during the non-mating seasons, most notably mouse and dwarf lemurs. The clitoral morphology of the ring-tailed lemur is the most well-studied. They are described as having "elongated, pendulous clitorises that are [fully] tunneled by a urethra". The urethra is surrounded by erectile tissue, which allows for significant swelling during breeding seasons, but this erectile tissue differs from the typical male corpus spongiosum. Non-pregnant adult ring-tailed females do not show higher testosterone levels than males, but they do exhibit higher A4 and estrogen levels during seasonal aggression. During pregnancy, estrogen, A4, and testosterone levels are raised, but female fetuses are still "protected" from excess testosterone.
A polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter—by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, or when biomass burns at lower temperatures as in forest fires. The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are also found in fossil fuel deposits such as coal and in petroleum. Exposure to PAHs can lead to different types of cancer, fetal development complications, and cardiovascular issues. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life.
Sources: en.wikipedia.org
denotes contact. The second assumption in contact mechanics is related to the fact, that no tension force is allowed to occur within the contact area (contacting bodies can be lifted up without adhesion forces). This leads to an inequality which the stresses have to obey at the contact interface. It is formulated for the normal stress
This species is of typical tetra shape but grows to a maximum overall length of approximately 2 cm (0.8 in) to 3 cm (1.2 in). Most exhibit striking orange and reddish coloration with mild translucency near the pelvic fin. The eye frequently mirrors the color of the fish and is outlined in black. The fish's natural diet consist of small invertebrates and plants. Although somewhat hard to find in fish stores, H. amandae is commonly kept as an aquarium fish by hobbyists.
=== Tandem Mobi === The Tandem Mobi is a smaller durable pump intended to be worn on the body or carried in clothing. It uses a 200-unit cartridge and is operated principally from a compatible smartphone app, while a physical button can deliver a preset bolus. The FDA cleared the pump in July 2023, and Tandem began its full United States launch in February 2024. The company obtained a CE mark for Mobi in 2025 and subsequently began introducing it in European markets.
Sources: en.wikipedia.org
== Function == PYY exerts its action through NPY receptors; it inhibits gastric motility and increases water and electrolyte absorption in the colon. PYY may also suppress pancreatic secretion. It is secreted by the neuroendocrine cells in the ileum and colon in response to a meal, and has been shown to reduce appetite. PYY works by slowing the gastric emptying; hence, it increases efficiency of digestion and nutrient absorption after a meal. Research has also indicated PYY may be useful in removing aluminium accumulated in the brain.
Codeine is an opiate and prodrug of morphine mainly used to treat pain, coughing, and diarrhea. It is commonly used as a recreational drug. It is found naturally in the sap of the opium poppy, Papaver somniferum. It is typically used to treat mild to moderate degrees of pain. Greater benefit may occur when combined with paracetamol (acetaminophen) as codeine/paracetamol or a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Evidence does not support its use for acute cough suppression in children. In Europe, it is not recommended as a cough medicine for those under 12 years of age. It is generally taken orally. It usually starts working after half an hour, with maximum effect at two hours. Its effects last for about four to six hours. Codeine exhibits abuse potential similar to other opioid medications, including a risk of addiction and overdose. Common side effects include nausea, vomiting, constipation, itchiness, lightheadedness, and drowsiness. Serious side effects may include breathing difficulties and addiction. Whether it can be used safely during pregnancy is unclear. Care should be used during breastfeeding, as it may result in opiate toxicity in the baby. Its use as of 2016 is not recommended for children. Codeine works by being broken down by the liver into morphine; how quickly this occurs depends on a person's genetics. Codeine was discovered in 1832 by Pierre Jean Robiquet. In 2013, about 361,000 kg (795,000 lb) of codeine were produced while 249,000 kg (549,000 lb) were used, which made it the most commonly taken opiate.
stimulating action through direct receptor agonism and downstream effects depressing action through direct receptor agonism and downstream effects (ex.: inverse agonist) blocking/antagonizing action (as with silent antagonists), the drug binds the receptor but does not activate it stabilizing action, the drug seems to act neither as a stimulant or as a depressant (ex.: some drugs possess receptor activity that allows them to stabilize general receptor activation, like buprenorphine in opioid dependent individuals or aripiprazole in schizophrenia, all depending on the dose and the recipient) exchanging/replacing substances or accumulating them to form a reserve (ex.: glycogen storage) direct beneficial chemical reaction as in free radical scavenging direct harmful chemical reaction which might result in damage or destruction of the cells, through induced toxic or lethal damage (cytotoxicity or irritation)
=== March === March 2 A major car crash in Imperial County, California kills 13 people and injures 13 others. COVID-19 pandemic Against CDC warnings, Texas Governor Greg Abbott lifts the statewide mask requirement and allows businesses to open at 100% capacity beginning March 10. Oregon reports its first cases of the Lineage P.1 variant in two people from Douglas County who previously traveled to Brazil. March 5 COVID-19 pandemic Illinois reports its first case of the Lineage P.1 variant first detected in Brazil in a person from Chicago. Tennessee reports its first case of the 501.V2 variant first detected in South Africa. March 6 – The Senate passes the American Rescue Plan Act, President Biden's $1.9 trillion COVID-19 relief package. March 7 – March 2021 Hawaii floods – Floods in Hawaii leave one missing, destroy six homes, force evacuations, and leave 1,300 without electricity. March 8 Missouri Senator Roy Blunt announces he will not run for re-election in 2022. The trial for Derek Chauvin, a former police officer involved in the murder of George Floyd last May, begins with jury selection. COVID-19 pandemic Hawaii reports its first case of South Africa's 501.V2 variant in an Oahu resident with no travel history. Michigan reports its first case of the 501.V2 variant in a child from Jackson County. March 10 COVID-19 pandemic Michigan surpasses 600,000 confirmed cases of COVID-19. New Jersey reports its first case of 501.V2 variant first detected in South Africa.
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and cleared quickly. Semaglutide carries a position 8 substitution that blocks that cleavage and a fatty diacid chain that binds albumin. Together these changes extend its circulating half-life to about one week.
Yes. Stimulation of insulin secretion is glucose-dependent, meaning the effect is larger when blood glucose is high and minimal when it is normal. This property separates GLP-1 receptor agonists from agents that drive insulin release regardless of glucose level.
Receptor expression in hypothalamic and brainstem regions is well documented, and reduced energy intake is consistently observed. The relative contribution of central versus peripheral signaling to total weight change is still an open question addressed by ongoing research.
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.