incretin hormone is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-12-06. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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。
| 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 |
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.
Lyophilised material appears as a white to off-white cake or powder that is hygroscopic, and containers are usually equilibrated to room temperature before opening to limit condensation. Dissolution is performed in water, phosphate-buffered saline, or a mildly alkaline buffer, since solubility rises above neutral pH. Gentle inversion or low-speed mixing is preferred, because vigorous vortexing can promote surface denaturation and aggregation. Complete dissolution may require several minutes, and brief sonication is sometimes applied. Passing the solution through a 0.22 micrometre membrane removes particulates but does not by itself sterilise the liquid.
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.
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.
Receptor activation raises intracellular cyclic AMP through Gs coupling, which promotes glucose-dependent insulin release and suppresses glucagon secretion when blood glucose is elevated. Effects outside the pancreas include slower gastric emptying and altered appetite signalling in the hypothalamus and hindbrain. The relative contribution of each tissue to overall metabolic outcomes remains an area of active investigation. Central mechanisms in particular are inferred mainly from animal models and indirect human measures rather than direct observation.
Leroy-Beaulieu was born in Rome. After spending her childhood in Italy where her father, Philippe Leroy, worked in the local film industry, she went to Paris at 16 to study drama against the advice of her parents; her father especially tried to keep her from pursuing a career that followed in his footsteps but was unsuccessful. After appearing on the stage, Leroy-Beaulieu made her screen début in Roger Vadim's 1983 comedy-drama film Surprise Party. The following year, she played Fauve Mistral in the 1984 mini-series version of Judith Krantz's novel Mistral's Daughter. In 1985, Leroy-Beaulieu played her first major screen role (and earned a nomination for the César Award for Most Promising Actress), playing the distraught mother in the Academy Award for Best Foreign Film-nominated comedy Trois hommes et un couffin (Three Men and a Cradle). The success of Coline Serreau's comedy helped her film career and a string of parts in costume films followed such films as Andrzej Wajda's Les Possédés in 1988, Philippe Le Guay's Les Deux Fragonard, and Robert Enrico's and Richard T. Heffron's La Révolution française (Mademoiselle Leroy-Beaulieu acted out the role of Charlotte Corday in the latter production), whose release in 1989 was timed to coincide with celebrations for the bi-centenary of the 1789 Revolution. Leroy-Beaulieu starred in the title role of the French film Natalia, which was screened at the 1988 Cannes Film Festival.
=== Multimodal methods === ImmunoStruct is a multimodal deep learning approach to immunogenicity prediction that fuses information from peptide–MHC sequence, structure, and biochemical properties. Rather than treating protein sequences as text alone, it combines complementary representations of the data to model interactions relevant to antigen presentation and T cell recognition. ImmunoStruct has demonstrated strong predictive performances on infectious disease epitopes (IEDB dataset) and human cancer neoepitopes (CEDAR dataset), and is generalizable to SARS-CoV-2 epitopes and cancer survival prediction. Its multimodal attention mechanism allows the model to differentially weight sequence, structural, and biochemical features for individual peptides, enabling analysis of structural determinants and peptide–MHC interactions associated with immunogenicity.
The increasing aggressiveness of Hitler prompted the Czechoslovak military to start to build extensive border fortifications in 1936 to defend the troubled border region. Immediately after the Anschluss of Austria into the German Reich in March 1938, Hitler made himself the advocate of ethnic Germans living in Czechoslovakia, which triggered the Sudeten Crisis. The following month, Sudeten Nazis, led by Konrad Henlein, agitated for autonomy. On 24 April 1938, the SdP proclaimed the Karlsbader Programm, which demanded in eight points the complete equality between the Sudeten Germans and the Czech people. The government accepted those claims on 30 June 1938. In August, British Prime Minister Neville Chamberlain sent Lord Runciman on a mission to Czechoslovakia to see if he could obtain a settlement between the Czechoslovak government and the Germans in the Sudetenland. Runciman's first day included meetings with President Beneš and Prime Minister Milan Hodža as well as a direct meeting with the Sudeten Germans from Henlein's SdP. On the next day, he met with Dr and Mme Beneš and later met non-Nazi Germans in his hotel. A full account of his report, including summaries of the conclusions of his meetings with the various parties, which he made in person to the Cabinet on his return to the United Kingdom, is found in the Document CC 39(38). Lord Runciman expressed sadness that he could not bring about agreement with the various parties, but he agreed with Lord Halifax that the time that had been gained was important.
Sources: en.wikipedia.org
For example, γδ T cells express a T-cell receptor comprising γ and δ chains instead of the α and β chains that conventional T cell receptors use, and they are able to recognize antigen without the need for presenting it on MHC proteins (though some have shown the ability to recognize MHC-presented antigens), instead having a mode of recognition that resembles that of antibodies, or recognizing phosphoantigens (antigens that are phosphorylated) through butyrophilin. Mucosa-associated invariant T cells (MAIT) cells recognize ligands presented by the MHC-related protein MR1, which presents metabolites of riboflavin, pyridoxine, and folates. NKT cells recognize glycolipid antigens presented on CD1d, most prominently α-galactosylceramide. In contrast to T cell receptors, antibodies can recognize any type of molecule at virtually any size and can recognize either linear or conformational epitopes (the amino acids that comprise an epitope do not need to be next to each other in the primary structure but do need to be near one another when the protein is folded). At the molecular level, an antigen can be characterized by its ability to bind to an antibody's paratopes. Different antibodies have the potential to discriminate among specific epitopes present on the antigen surface.
Sheikh Muszaphar later regarded Mahathir as the 'father of Malaysia's space programme.' At UMNO's general assembly in 2002, he announced that he would resign as prime minister, only for supporters to rush to the stage and convince him tearfully to remain. He subsequently fixed his retirement for October 2003, giving him time to ensure an orderly and uncontroversial transition to his anointed successor, Abdullah Badawi. Mahathir simultaneously pledged that he would not take on an elder statesman role after retirement. During his final year in office, Mahathir introduced the teaching of Mathematics and Science in English (PPSMI) in 2003, believing that it is crucial for Malaysians to remain competitive in a fast-changing world. During the Severe Acute Respiratory Syndrome (SARS) outbreak, Mahathir introduced an RM8 billion stimulus package, contributing to Malaysia's 6.5% economic growth in the third quarter of 2003. The package focused on four main strategies and 90 measures to stimulate economic activity, boost consumption, and encourage investment. On 29 October 2003, the cabinet paid tribute to Mahathir for his invaluable service to the nation as prime minister for the last 22 years. He also received a record-breaking outpouring of public gratitude, marked by a 5.5 km-long banner displaying messages from over 50,000 Malaysians. The following day, Mahathir presented a review of Malaysia's five-year economic plan at Parliament House. Having spent over 22 years in office, Mahathir was the world's longest-serving elected leader when he retired on 31 October 2003.
==== Australia ==== Harmala alkaloids are considered Schedule 9 prohibited substances under the Poisons Standard (October 2015). A Schedule 9 substance is a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities.
The side effects of estradiol cypionate are the same as those of estradiol. Examples of such side effects include breast tenderness and enlargement, nausea, vomiting, bloating, edema, headache, migraine, and melasma. High-dose estrogen therapy with estradiol cypionate injections may also cause an increased risk of thromboembolism, changes in blood lipid profile, increased insulin resistance, and increased levels of prolactin.
Sources: en.wikipedia.org
Single nucleotide polymorphisms (SNPs) play an important role in genome wide association studies because they act as primary biomarkers. SNPs are currently the marker of choice due to their large numbers in virtually all populations of individuals. The location of these biomarkers can be tremendously important in terms of predicting functional significance, genetic mapping and population genetics. Each SNP represents a nucleotide change between two individuals at a defined location. SNPs are the most common genetic variant found in all individual with one SNP every 100–300 bp in some species. Since there is a massive number of SNPs on the genome, there is a clear need to prioritize SNPs according to their potential effect in order to expedite genotyping and analysis.
Vantin (by Pfizer) in suspension or tablet form. Toraxim (by Delta Pharma Ltd., Bangladesh) Trucef (by Renata Limited, Bangladesh) Tricef (by Alkaloid Skopje, North Macedonia) Orelox (by Sanofi-Aventis) MAPDOX-CV: Combination cefpodoxime–clavulanic acid MONOTAX O (cefpodoxime)/MONOTAX CV (cefpodoxime–clavulanic acid) by Zydus Healthcare Ltd. ACXIME 200/CV (by Allencia Biosciences, India) POSTPOD-50 (cefpodoxime 50mg/5ml) by Laafon Galaxy Pharmaceuticals
13 October NASA launches its Psyche mission to visit the large metallic asteroid 16 Psyche. A meta-analysis finds that three doses of a COVID-19 vaccine offer 69% effectiveness against long COVID, while two doses offer 37% efficacy. 21 studies provide new insights about the human brain at the cellular level such as identifying and characterizing differentially expressed genes in shared cell-types in a language-associated region of the cortex compared to other apes and showing human variability of the expression of 150–250 genes for most cell types of profiled cortical tissues of 75 individuals with brain diseases. A policy studies review of 200 guidelines about AI ethics, safety and governance summarizes resonating principles and common concerns, providing an evaluating situation report amid what it calls an "AI ethics boom". 14 October – The Joint European Torus nuclear fusion laboratory conducts its final experiments after 40 years in operation.
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.
差别集中在三处：第 8 位残基被非天然氨基酸取代，第 34 位换成精氨酸，第 26 位增加一条脂肪酸侧链。前两处改动降低酶解速率，侧链则通过白蛋白结合延长循环时间。综合结果是半衰期从约两分钟延长到约一周。