This is a working overview of GLP-1, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-10-25 and is reviewed periodically as new material appears.
The compound binds the GLP-1 receptor on pancreatic beta cells and other tissues, activating a G-protein signaling cascade that raises intracellular cyclic AMP. This action increases glucose-dependent insulin secretion when blood glucose is elevated, while binding also slows gastric emptying and reduces glucagon release. In the central nervous system, receptor activation in the hypothalamus and brainstem contributes to reduced appetite. The fatty acid chain binds albumin, which protects the peptide from renal filtration and enzymatic degradation. This albumin binding is central to its extended circulation time.
Native GLP-1 is degraded rapidly by dipeptidyl peptidase-4. Semaglutide resists this cleavage because alanine at position 8 is replaced by alpha-aminoisobutyric acid. A second substitution at position 34 introduces arginine, which further stabilizes the peptide. The most distinctive modification is a spacer and C18 fatty diacid attached at lysine 26, enabling strong albumin affinity. These three changes together produce a half-life measured in days rather than minutes, and the same structural logic underlies other long-acting analogs in this class.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | 31 amino acids |
| Backbone modification | Aib at position 8 | Blocks DPP-4 cleavage |
| Fatty acid chain | C18 diacid | Supports albumin binding |
| Native half-life | 1 to 2 minutes | Endogenous GLP-1 |
| Analog half-life | Approximately one week | Extended by albumin binding |
纯度评价多采用反相高效液相色谱，流动相常加入三氟乙酸或甲酸作为离子对改性剂，检测波长设在二百一十四纳米或二百二十纳米。分子量确认依靠电喷雾电离质谱或基质辅助激光解吸电离质谱，实测值应与理论值在数 ppm 内吻合。肽图分析通过酶切后液相色谱串联质谱完成，用于核查序列与修饰位点。体积排阻色谱用于定量共价与非共价聚集体。生物基质浓度测定则采用免疫分析或液相色谱串联质谱。
肽类的主要降解路径包括天冬酰胺脱酰胺、甲硫氨酸氧化、天冬氨酸异构化以及由 β-折叠驱动的聚集，这些反应对 pH 与缓冲液种类较为敏感。磷酸盐、丙二醇与苯酚等辅料会影响局部微环境与界面行为。强制降解研究借助高温、强光、氧化剂与极端 pH 暴露来预测产物谱。关于长期室温存放的数据相对有限，超出标签条件的稳定性仍属开放问题，需要在具体制剂中通过实时与加速试验加以确认。
容器与密封系统同样参与稳定性表现。硅油涂层、胶塞材质与顶空氧含量可能改变聚集速率与氧化水平。分析结果因此需要在完整包装形式下评估，而不能仅凭原料药数据推断。法规文件通常要求同时提交批次数据与代表性容器中的稳定性趋势。
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.
Lyophilised semaglutide is generally held at -20 °C or below, protected from light and moisture. Reconstituted solutions are typically kept at 2-8 °C and used within a defined window because degradation accumulates over time. Repeated freeze-thaw cycles are discouraged, since each cycle can promote aggregation and reduce monomeric content. Room-temperature stability of the solid has been examined in some studies but remains incompletely characterised for long durations, so cold storage is the conservative default for research material.
Degradation proceeds along several parallel routes. Deamidation of asparagine and glutamine residues generates charged variants that shift retention time in chromatographic analysis. Oxidation targets methionine and can be accelerated by trace metals or dissolved oxygen. Non-covalent aggregation produces dimers, oligomers, and larger species that are difficult to reverse. Isomerisation at aspartate residues is slower but measurable under thermal stress. The distribution among these pathways depends on pH, buffer composition, ionic strength, and the presence of excipients such as sugars or surfactants.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nm is the standard purity method, reported as area percent. Mass spectrometry, usually with electrospray ionisation, confirms identity and reveals covalent modifications. Size-exclusion chromatography quantifies aggregates and fragments. Peptide mapping after enzymatic digestion localises changes to specific sequence regions. Circular dichroism and infrared spectroscopy report on secondary structure, while light scattering tracks particle formation in liquid formulations. No single technique captures every quality attribute.
Enobosarm is not subject to this local transformation and potentiation, and so is theorized to have greatly reduced effects in these tissues relative to testosterone and certain other steroidal androgens. This is likewise theorized to be the case for non-5α-reductase-potentiated anabolic steroids like nandrolone and oxandrolone, which have high myotrophic–androgenic potency ratios in animals. The lack of 5α-reduction may result in reduced androgenic side effects like scalp hair loss, facial and body hair growth, and prostate growth. On the other hand, although SARMs, like enobosarm, as well as anabolic steroids, may have reduced virilizing effects in skin and hair follicles, this is not necessarily the case for virilization in general. In particular, the muscle-promoting effects of these agents can be considered a masculinizing effect. The potential masculinizing effects of enobosarm and SARMs in general are largely uncharacterized and unknown. Aside from metabolism differences related to 5α-reduction, enobosarm has also shown much greater impact in the liver, specifically on certain aspects of hepatic protein synthesis like reduction of sex hormone-binding globulin (SHBG) production, than even highly supraphysiological doses of parenteral testosterone. This phenomenon has also been seen with other SARMs, such as LGD-4033, as well as with synthetic orally active 17α-alkylated anabolic steroids like stanozolol.
1854: British conchologist and geologist Mary Horner Lyell is most well known for her scientific work in 1854, where she studied her collection of land snails from the Canary Islands. She was married to the notable British geologist Charles Lyell and assisted him in his scientific work. It is believed by historians that she likely made major contributions to her husband's work. 1854–1855: English social reformer and statistician, and the founder of modern nursing Florence Nightingale organized care for wounded soldiers during the Crimean War. Her pie charts clearly showed that most deaths resulted from disease rather than battle wounds or "other causes," which led the general public to demand improved sanitation at field hospitals. 1855: Working with her father, Welsh astronomer and photographer Thereza Dillwyn Llewelyn produced some of the earliest photographs of the moon. 1856: American atmospheric scientist Eunice Newton Foote presented her paper "Circumstances affecting the heat of the sun's rays" at an annual meeting of the American Association for the Advancement of Sciences. She was an early researcher of the greenhouse effect. 1862: Belgian botanist Marie-Anne Libert became the first woman to join the Royal Botanical Society of Belgium. She was named an honorary member. 1863: German naturalist Amalie Dietrich arrived in Australia to collect plant, animal and anthropological specimens for the German Godeffroy Museum.
=== EC 1.13.11 With incorporation of two atoms of oxygen === EC 1.13.11.1: catechol 1,2-dioxygenase EC 1.13.11.2: catechol 2,3-dioxygenase EC 1.13.11.3: protocatechuate 3,4-dioxygenase EC 1.13.11.4: gentisate 1,2-dioxygenase EC 1.13.11.5: homogentisate 1,2-dioxygenase EC 1.13.11.6: 3-hydroxyanthranilate 3,4-dioxygenase EC 1.13.11.7: deleted EC 1.13.11.8: protocatechuate 4,5-dioxygenase EC 1.13.11.9: 2,5-dihydroxypyridine 5,6-dioxygenase EC 1.13.11.10: 7,8-dihydroxykynurenate 8,8a-dioxygenase EC 1.13.11.11: tryptophan 2,3-dioxygenase EC 1.13.11.12: linoleate 13S-lipoxygenas EC 1.13.11.13: The activity is the sum of several enzymatic and spontaneous reactions EC 1.13.11.14: 2,3-dihydroxybenzoate 3,4-dioxygenase EC 1.13.11.15: 3,4-dihydroxyphenylacetate 2,3-dioxygenase EC 1.13.11.16: 3-carboxyethylcatechol 2,3-dioxygenase EC 1.13.11.17: indole 2,3-dioxygenase EC 1.13.11.18: persulfide dioxygenase EC 1.13.11.19: cysteamine dioxygenase EC 1.13.11.20: cysteine dioxygenase EC 1.13.11.21: Now EC 1.14.99.36, β-carotene 15,15′-monooxygenase EC 1.13.11.22: caffeate 3,4-dioxygenase EC 1.13.11.23: 2,3-dihydroxyindole 2,3-dioxygenase EC 1.13.11.24: quercetin 2,3-dioxygenase EC 1.13.11.25: 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione 4,5-dioxygenase EC 1.13.11.26: peptide-tryptophan 2,3-dioxygenase EC 1.13.11.27: 4-hydroxyphenylpyruvate dioxygenase EC 1.13.11.28: 2,3-dihydroxybenzoate 2,3-dioxygenase EC 1.13.11.29: stizolobate synthase EC 1.13.11.30: stizolobinate synthase EC 1.13.11.31: arachidonate 12-lipoxygenase EC 1.13.11.32: Now EC 1.13.12.16, nitronate monooxygenase EC 1.13.11.33: arachidonate 15-lipoxygenase EC 1.13.11.34: arachidonate 5-lipoxygenase EC 1.13.11.35: pyrogallol 1,2-oxygenase EC 1.13.11.36: chloridazon-catechol dioxygenase EC 1.13.11.37: hydroxyquinol 1,2-dioxygenase EC 1.13.11.38: 1-hydroxy-2-naphthoate 1,2-dioxygenase EC 1.13.11.39: biphenyl-2,3-diol 1,2-dioxygenase EC 1.13.11.40: arachidonate 8-lipoxygenase EC 1.13.11.41: 2,4′-dihydroxyacetophenone dioxygenase EC 1.13.11.42: identical to EC 1.13.11.11, tryptophan 2,3-dioxygenase EC 1.13.11.43: lignostilbene αβ-dioxygenase EC 1.13.11.44: Activity is covered by EC 1.13.11.60, linoleate 8R-lipoxygenase and EC 5.4.4.6, 9,12-octadecadienoate 8-hydroperoxide 8S-isomerase EC 1.13.11.45: linoleate 11-lipoxygenase EC 1.13.11.46: 4-hydroxymandelate synthase EC 1.13.11.47: 3-hydroxy-4-oxoquinoline 2,4-dioxygenase EC 1.13.11.48: 3-hydroxy-2-methyl-quinolin-4-one 2,4-dioxygenase EC 1.13.11.49: chlorite O2-lyase EC 1.13.11.50: acetylacetone-cleaving enzyme EC 1.13.11.51: 9-cis-epoxycarotenoid dioxygenase EC 1.13.11.52: indoleamine 2,3-dioxygenase EC 1.13.11.53: acireductone dioxygenase (Ni2+-requiring) EC 1.13.11.54: acireductone dioxygenase [iron(II)-requiring] EC 1.13.11.55: sulfur oxygenase/reductase EC 1.13.11.56: 1,2-dihydroxynaphthalene dioxygenase EC 1.13.11.57: gallate dioxygenase EC 1.13.11.58: linoleate 9S-lipoxygenase EC 1.13.11.59: torulene dioxygenase EC 1.13.11.60: inoleate 8R-lipoxygenase EC 1.13.11.61: linolenate 9R-lipoxygenase EC 1.13.11.62: linoleate 10R-lipoxygenase EC 1.13.11.63: β-carotene 15,15′-dioxygenase EC 1.13.11.64: 5-nitrosalicylate dioxygenase EC 1.13.11.65: carotenoid isomerooxygenase EC 1.13.11.66: hydroquinone 1,2-dioxygenase EC 1.13.11.67: 8′-apo-β-carotenoid 14′,13′-cleaving dioxygenase EC 1.13.11.68: 9-cis-β-carotene 9′,10′-cleaving dioxygenase EC 1.13.11.69: carlactone synthase EC 1.13.11.70: all-trans-10′-apo-β-carotenal 13,14-cleaving dioxygenase EC 1.13.11.71: carotenoid-9′,10′-cleaving dioxygenase EC 1.13.11.72: 2-hydroxyethylphosphonate dioxygenase EC 1.13.11.73: methylphosphonate synthase EC 1.13.11.74: 2-aminophenol 1,6-dioxygenase EC 1.13.11.75: all-trans-8′-apo-β-carotenal 15,15′-oxygenase EC 1.13.11.76: 2-amino-5-chlorophenol 1,6-dioxygenase EC 1.13.11.77: oleate 10S-lipoxygenase EC 1.13.11.78: 2-amino-1-hydroxyethylphosphonate dioxygenase (glycine-forming) EC 1.13.11.79: aerobic 5,6-dimethylbenzimidazole synthase EC 1.13.11.80: (3,5-dihydroxyphenyl)acetyl-CoA 1,2-dioxygenase EC 1.13.11.81: 7,8-dihydroneopterin oxygenase EC 1.13.11.82: 8′-apo-carotenoid 13,14-cleaving dioxygenase EC 1.13.11.83: 4-hydroxy-3-prenylphenylpyruvate oxygenase EC 1.13.11.84: crocetin dialdehyde synthase EC 1.13.11.85: exo-cleaving rubber dioxygenase EC 1.13.11.86: 5-aminosalicylate 1,2-dioxygenase EC 1.13.11.87: endo-cleaving rubber dioxygenase EC 1.13.11.88: isoeugenol monooxygenase EC 1.13.11.89: (hydroxymethyl)phosphonate dioxygenase EC 1.13.11.90: [1-hydroxy-2-(trimethylamino)ethyl]phosphonate dioxygenase (glycine-betaine-forming) EC 1.13.11.91: 3-mercaptopropionate dioxygenase EC 1.13.11.92: fatty acid α-dioxygenase
Sources: en.wikipedia.org
=== Military garrisons and agricultural colonies === The first emperor Qin Shi Huang is said to have sent several hundred thousand men and fifteen thousand women to form agricultural and military settlements in Lingnan (present day Guangxi and Guangdong), under the leadership of a general named Zhao Tuo. The famous Han emperor, Han Wu Di, ordered another two hundred thousand men to build ships to attack and colonialize the Lingnan region, adding to the population in Guangdong and Guangxi. The first urban conurbations in the region, for example, Panyu, were created by Han settlers rather than the Bai Yue, who preferred to maintain small settlements subsisting on swidden agriculture and rice farming. Later on, Guangdong, northern Vietnam, and Yunnan all experienced a surge in Han Chinese migrants during Wang Mang's reign. The demographic composition and culture of these regions during this period, could however scarcely be said to have been Sinitic outside the confines of these agricultural settlements and military outposts.
Anthony Tiran Todd (December 4, 1954 – November 6, 2024) was an American actor. Known for his distinctly deep and gravelly voice, he amassed numerous credits on screen and in video games since the 1980s, including the title character in the Candyman film series (1992–2021) and William Bludworth in the Final Destination franchise (2000–2025). For the former, he was nominated at the Critics' Choice and Fangoria Chainsaw Awards. Todd's films include Platoon (1986), Night of the Living Dead (1990), The Crow (1994), The Rock (1996), Wishmaster (1997), Hatchet, Minotaur (both 2006), The Man from Earth (2007), Frankenstein (2015), Death House (2017), and Hell Fest (2018). On television, he played Kurn in Star Trek: The Next Generation (1990–1991) and Star Trek: Deep Space Nine (1996), Lord Haikon on Stargate SG-1 (2005–2006), and appeared in the MTV series Scream (2019) and Devil May Cry (2025). Todd was a prolific voice actor, notably voicing the Vortigaunts in the Half-Life series of games, the Fallen in Michael Bay's Transformers: Revenge of the Fallen (2009), Zoom in The Flash (2014–2023), Darkseid in the DC Animated Movie Universe (2015–2020), Venom in the video game Marvel's Spider-Man 2 (2023), and Locus in the video game Indiana Jones and the Great Circle (2024). For Spider-Man 2, he received a British Academy Games Award nomination.
Icalcaprant (developmental code name CVL-354) is a κ-opioid receptor (KOR) antagonist which is under development for the treatment of major depressive disorder and substance-related disorders. It is taken by mouth. It acts as a selective antagonist of the KOR. The drug is also more weakly an antagonist of the μ-opioid receptor (MOR), with about 31-fold lower affinity and 27-fold lower inhibitory potency at the MOR relative to the KOR. It was originated by Pfizer and is under development by Cerevel Therapeutics (a subsidiary of AbbVie). As of September 2022, icalcaprant is in phase 1 clinical trials for major depressive disorder and is in the preclincal stage of development for substance-related disorders.
Sources: en.wikipedia.org
The muscle cell is damaged by the depletion of ATP and possibly the high temperatures, and cellular constituents "leak" into the circulation, including potassium, myoglobin, creatine, phosphate and creatine kinase. The other known causative gene for MH is CACNA1S, which encodes an L-type voltage-gated calcium channel α-subunit. There are two known mutations in this protein, both affecting the same residue, R1086. This residue is located in the large intracellular loop connecting domains 3 and 4, a domain possibly involved in negatively regulating RYR1 activity. When these mutant channels are expressed in human embryonic kidney (HEK 293) cells, the resulting channels are five times more sensitive to activation by caffeine (and presumably halothane) and activate at 5–10mV more hyperpolarized. Furthermore, cells expressing these channels have an increased basal cytosolic Ca2+ concentration. As these channels interact with and activate RYR1, these alterations result in a drastic increase of intracellular Ca2+, and, thereby, muscle excitability. Other mutations causing MH have been identified, although in most cases the relevant gene remains to be identified.
A typical Indian meal is built on a plain cereal, complemented by savoury dishes. The cooked cereal could be steamed rice; chapati, a thin unleavened bread; idli, a steamed breakfast cake; or dosa, a griddled pancake. The savoury dishes might include lentils, pulses, vegetables, meat, poultry and fish commonly spiced with ginger and garlic, but also coriander, cumin, turmeric, cinnamon, cardamom and others. In some instances, the ingredients may be mixed during the cooking process. India has distinctive vegetarian cuisines, each a feature of the geographical and cultural histories of its communities. About 20% to 39% of India's population consists of vegetarians. Although meat is eaten widely, the proportional consumption of meat is low. The most significant import of cooking techniques into India during the last millennium occurred during the Mughal Empire, spreading into northern India from regions to its northwest, along with dishes such as pilaf. Onions, garlic, almonds, and spices were added to the simple yogurt marinade of Persia. Rice was partially cooked and layered alternately with sauteed meat, the pot sealed tightly, and slow cooked according to another Persian cooking technique, to produce biryani, a feature of festive dining in many parts of India. The diversity of Indian food served worldwide has been partially concealed by the dominance of Punjabi cuisine.
Many types of benign tumors have the potential to become cancerous (malignant) through a process known as tumor progression. For this reason and other possible harms, some benign tumors are removed by surgery. When removed, benign tumors usually do not return. Exceptions to this rule may indicate malignant transformation.
== Lipid transportation == Due to the hydrophobic nature of membrane lipids, triglycerides and cholesterol, they require special transport proteins known as lipoproteins. The amphipathic structure of lipoproteins allows the triglycerides and cholesterol to be transported through the blood. Chylomicrons are one sub-group of lipoproteins which carry the digested lipids from small intestine to the rest of the body. The varying densities between the types of lipoproteins are characteristic to what type of fats they transport. For example, very-low-density lipoproteins (VLDL) carry the triglycerides synthesized by our body and low-density lipoproteins (LDL) transport cholesterol to our peripheral tissues. A number of these lipoproteins are synthesized in the liver, but not all of them originate from this organ.
Sources: en.wikipedia.org
It is a synthetic analog of GLP-1 produced through medicinal chemistry to resist enzymatic degradation. The design goal was longer circulation than the native hormone.
A fatty acid side chain attaches the peptide to serum albumin, which shields it from kidney filtration and protease activity. This interaction is the main reason its circulation time is extended.
No. The native hormone is GLP-1, and semaglutide is an engineered variant with three deliberate structural alterations. It does not appear in unmodified biological sources.
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.