This is a working overview of GLP-1 receptor agonist, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-08. Anything still debated is marked as such rather than presented as settled.
Three structural changes define the molecule. At position 8 an alpha-aminoisobutyric acid residue replaces alanine, which blocks dipeptidyl peptidase-4 cleavage. At position 34 arginine replaces lysine, and at position 26 a lysine carries a C18 fatty diacid attached through a short linker. The fatty chain binds serum albumin, and this albumin association reduces renal filtration and enzymatic attack. The unchanged backbone retains the receptor contacts that produce signalling. The free base has the formula C187H291N45O59 and a molecular weight near 4114 daltons.
Receptor activation follows the canonical Gs pathway: binding increases intracellular cyclic AMP, which promotes protein kinase A activity. In pancreatic beta cells this amplifies glucose-dependent insulin release, so secretion rises when blood glucose is high and changes little when it is low. The same signalling suppresses glucagon release from alpha cells and slows gastric emptying. Receptors in the hypothalamus and brainstem are thought to contribute to reduced appetite and lower energy intake. Which of these effects dominates clinical outcomes remains an area of active study.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | free base, without counter-ion |
| Molecular weight | About 4114 Da | peptide backbone plus attached lipid chain |
| Plasma half-life | About 165 hours | supports once-weekly dosing in humans |
| Plasma protein binding | Greater than 99 percent | attributed mainly to serum albumin |
| Receptor target | GLP-1 receptor | Gs-coupled, raises intracellular cyclic AMP |
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 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.
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 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。
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.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released after nutrient intake. The molecule contains 31 amino acid residues and differs from the native sequence at several positions. A non-natural residue at position eight resists the enzyme that normally truncates the hormone, while a lysine-linked fatty diacid side chain promotes binding to serum albumin. These two modifications extend the circulating half-life from minutes to roughly one week. The peptide is produced by solid-phase synthesis followed by selective acylation, and its identity and purity are confirmed by spectrometric and chromatographic techniques.
After the collapse of the Kingdom of Yugoslavia in the April War (1941), the entire country was occupied and partitioned between Axis powers. Central territories of Serbia and the northern region of Banat were occupied by Nazi Germany, that enforced direct control over the Territory of the Military Commander in Serbia, with a puppet Government installed in Belgrade. Southern regions of Metohija and Kosovo were occupied by Fascist Italy and annexed into the Italian Albania. The region of Bačka was annexed by Hungary, while Syrmia was possessed by the Independent State of Croatia. Southeastern parts of Serbia were occupied by Bulgaria. At the beginning of the occupation, there were two resistance movements: Chetniks and Partisans. They had conflicting ideological and political programs, with Chetniks abandoning initial joint resistance efforts alongside Partisans by the end of the Uprising in Serbia, switching instead to extensive collaboration with Axis forces. Partisans advocated transformation of Yugoslavia into a federation, with Serbia becoming one of its federal units. In the autumn of 1941, first provisional institutions were established by partisans in some liberated territories, headed by the Main National Liberation Committee for Serbia. It was seated in Užice, and thus the movement became known as the Republic of Užice. However, the German offensive crushed this proto-state in December of the same year. After that, main partisan forces moved to Bosnia.
Trap-jaw ants of the genus Odontomachus are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom. One study of Odontomachus bauri recorded peak speeds of between 126 and 230 km/h (78 and 143 mph), with the jaws closing within 130 microseconds on average. The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backward to escape a threat. Before striking, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory organs resembling hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws also are seen in other ponerines such as Anochetus, as well as some genera in the tribe Attini, such as Daceton, Orectognathus, and Strumigenys, which are viewed as examples of convergent evolution. A Malaysian species of ant in the Camponotus cylindricus group has enlarged mandibular glands that extend into their gaster. If combat takes a turn for the worse, a worker may perform a final act of suicidal altruism by rupturing the membrane of its gaster, causing the content of its mandibular glands to burst from the anterior region of its head, spraying a poisonous, corrosive secretion containing acetophenones and other chemicals that immobilise small insect attackers. The worker subsequently dies.
=== APOA-I: A Possible Novel Biomarker for Metabolic Side Effects in First Episode Schizophrenia === The authors of this study sought to determine the effect on metabolism of the drug risperidone in schizophrenia patients. After discovering that risperidone did have negative metabolic side effects, they tested membrane proteins for glucose and lipid transport in control and experimental groups by MALDI-TOF and fingerprinting. Results showed altered fingerprints and therefore altered levels of folding in the proteins. So, they concluded that risperidone negatively effects glucose and lipid transport proteins in the cell membranes of patients.
Brewing yeasts may be classed as "top-cropping" (or "top-fermenting") and "bottom-cropping" (or "bottom-fermenting"). Top-cropping yeasts are so called because they form a foam at the top of the wort during fermentation. An example of a top-cropping yeast is Saccharomyces cerevisiae, sometimes called an "ale yeast". Bottom-cropping yeasts are typically used to produce lager-type beers, though they can also produce ale-type beers. These yeasts ferment well at low temperatures. An example of bottom-cropping yeast is Saccharomyces pastorianus, formerly known as S. carlsbergensis. Decades ago, taxonomists reclassified S. carlsbergensis (uvarum) as a member of S. cerevisiae, noting that the only distinct difference between the two is metabolic. Lager strains of Saccharomyces secrete an enzyme called melibiase, allowing them to hydrolyse melibiose, a disaccharide, into more fermentable monosaccharides. Top- and bottom-cropping and cold- and warm-fermenting distinctions are largely generalizations used by laypersons to communicate to the general public. The most common top-cropping brewer's yeast, S. cerevisiae, is the same species as the common baking yeast. Brewer's yeast is also very rich in essential minerals and the B vitamins (except B12), a feature exploited in food products made from leftover (by-product) yeast from brewing.
== Relationship with astrobiology == Endolithic microorganisms have been considered a model for the search for life on other planets by inquiring about what sort of microorganisms on Earth inhabit specific minerals, which helps to propose those lithologies as life detection targets on an extra-terrestrial surface such as Mars. Several studies have been carried out in extreme places that serve as analogs for Mars's surface and subsurface, and many studies in geomicrobiology on Earth's hot and cold deserts have been developed. In these extreme environments, microorganisms find protection against thermal buffering, UV radiation, and desiccation while living inside pores and fissures of minerals and rocks. Life in these endolithic habitats might face similar stress due to the scarcity of water and high UV radiation that rule on modern Mars. An excellent example of these adaptations is the non-hygroscopic but microporous translucent gypsum crusts, which are found as potential substrates that can mitigate exposure to UV radiation and desiccation and allow microbial colonization in hyper-arid deserts. In the same way, the ability to grow under high water stress and oligotrophic conditions confer to endolithic microorganisms to survive in conditions similar to those found on Mars. There is evidence of the past existence of water on the red planet; perhaps, these microorganisms could develop adaptations found in current deserts on the Earth.
Sources: en.wikipedia.org
diakinesis In meiosis, the fifth and final substage of prophase I, following diplonema and preceding metaphase I. During diakinesis, the chromosomes are further condensed, the two centrosomes reach opposite poles of the cell, and the spindle apparatus begins to extend from the poles to the equator.
== Application in human evolution and disease == In the human genome, the frequency and characteristics of de novo mutations have been studied as important contextual factors to our evolution. Compared to the human reference genome, a typical human genome varies at approximately 4.1 to 5.0 million loci, and the majority of this genetic diversity is shared by nearly 0.5% of the population. The typical human genome also contains 40,000 to 200,000 rare variants observed in less than 0.5% of the population that can only have occurred from at least one de novo germline mutation in the history of human evolution. De novo mutations have also been researched as playing a crucial role in the persistence of genetic disease in humans. With recents advancements in next-generation sequencing (NGS), all types of de novo mutations within the genome can be directly studied, the detection of which provides a magnitude of insight toward the causes of both rare and common genetic disorders. Currently, the best estimate of the average human germline SNV mutation rate is 1.18 x 10^-8, with an approximate ~78 novel mutations per generation. The ability to conduct whole genome sequencing of parents and offspring allows for the comparison of mutation rates between generations, narrowing down the origin possibilities of certain genetic disorders.
=== Single particles === Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) was designed for particle suspensions in 2000 by Claude Degueldre. He first tested this new methodology at the Forel Institute of the University of Geneva and presented this approach at the 'Colloid 2oo2' symposium during the spring 2002 meeting of the EMRS, and in the proceedings in 2003. This study presents the theory of SP ICP-MS and the results of tests carried out on clay particles (montmorillonite) as well as other suspensions of colloids. This method was then tested on thorium dioxide nanoparticles, zirconium dioxide and gold nanoparticles and uranium dioxide nano- and micro-particles.
== Background == Marley was born in Covina, California and raised in Salem, Oregon. Growing up, Marley was a reptile enthusiast. From his earliest memories, Marley was always drawing, and most often his subject was monsters. His father was an aviarist and breeder of rare color mutations of Australian parrots and great blue turacos. Marley served as a missionary in the Atacama Desert in Chile for two years at 19 years old. After this, he studied design at Brigham Young University. During university, he took sabbaticals to work with fashion brands such as Donna Karan, Gucci, Nike, and Giorgio Armani.
Glucose transporter type 4 (GLUT4), also known as solute carrier family 2, facilitated glucose transporter member 4, is a protein encoded, in humans, by the SLC2A4 gene. GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). GLUT4 is distinctive because it is predominantly stored within intracellular vesicles, highlighting the importance of its trafficking and regulation as a central area of research. The first evidence for this glucose transport protein was provided by David James in 1988. The gene that encodes GLUT4 was cloned and mapped in 1989. At the cell surface, GLUT4 permits the facilitated diffusion of circulating glucose down its concentration gradient into muscle and fat cells. Once within cells, glucose is rapidly phosphorylated by glucokinase in the liver and hexokinase in other tissues to form glucose-6-phosphate, which then enters glycolysis or is polymerized into glycogen. Glucose-6-phosphate cannot diffuse back out of cells, which also serves to maintain the concentration gradient for glucose to passively enter cells.
Sources: en.wikipedia.org
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over 100 μM; its mass is roughly 42 kDa, with a diameter of 4 to 7 nm. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells. It can be present as either a free monomer called G-actin (globular) or as part of a linear polymer microfilament called F-actin (filamentous), both of which are essential for the cellular functions of mobility and the contraction of cells during cell division. Actin participates in many important cellular processes, including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape. Many of these processes are mediated by extensive and intimate interactions of actin with cellular membranes. In vertebrates, three main groups of actin isoforms, alpha, beta, and gamma have been identified. The alpha actins, found in muscle tissues, are a major constituent of the contractile apparatus. The beta and gamma actins coexist in most cell types as components of the cytoskeleton, and as mediators of internal cell motility.
More recently, the initiative focused on improving security around Mexico's southern border and countering the production and trafficking of heroin and fentanyl. Until March 2017, more than $1.6bn has been invested in the Merida initiative, of which almost $900,000 was spent on protective equipment necessary for the secured demolishing of narcotic labs. In Mexico, the DEA combats operations of DTOs by conducting bilateral investigations with foreign counterparts, providing investigative assistance and leads to DEA domestic offices and other agencies, providing training and technical equipment to 'host nation participants to initiate and carry out complex criminal investigations, providing assistance in developing drug control laws and regulations, and providing training and material support to foreign law enforcement counterparts'.
=== North America === Accium BioSciences at Swedish Medical Center Cherry Hill, Seattle, WA André E. Lalonde Accelerator Mass Spectrometry Laboratory (AEL AMS) at the University of Ottawa in Ottawa, Canada Beta Analytic Accelerator Mass Spectrometry Facility in Miami, Florida Center for Accelerator Mass Spectrometry (CAMS) at the Lawrence Livermore National Laboratory Center for Applied Isotope Studies (CAIS) at University of Georgia. DirectAMS (D-AMS) radiocarbon labs in Bothell, WA & Seattle, WA Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan Institute for Structure and Nuclear Astrophysics, The University of Notre Dame, Notre Dame, Indiana Institute of Energy and the Environment Radiocarbon Laboratory at the Pennsylvania State University, University Park, Pennsylvania MegaSIMS at the University of California, Los Angeles in Los Angeles, CA National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic Institution NSF - Arizona Accelerator Mass Spectrometry (AMS) Laboratory Pharmaron ABS, Inc. in Germantown, Maryland Purdue Rare Isotope Measurement Laboratory at Purdue University in West Lafayette, Indiana Trace Element Accelerator Mass Spectrometer (TEAMS) at the Naval Research Laboratory in Washington, DC W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (KCCAMS) Facility at the University of California, Irvine
An ultra low temperature (ULT) freezer is a refrigerator that stores contents at −80 to −86 °C (−112 to −123 °F). An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature standard. ULT freezers come in upright and chest freezer formats.
Sources: en.wikipedia.org
Native GLP-1 is a short-lived peptide cleared within one to two minutes by dipeptidyl peptidase-4 and related enzymes. Semaglutide keeps the receptor-binding backbone but adds substitutions and a lipid chain. These changes block the main cleavage site and allow reversible albumin binding, extending the half-life to roughly 165 hours.
Albumin is the most abundant protein in plasma and carries molecules that bear fatty-acid chains. Binding shields the peptide from renal filtration and from peptidases, keeping a circulating reservoir. Slow release from this reservoir produces sustained receptor occupancy and supports infrequent dosing.
The insulinotropic effect is glucose-dependent, meaning secretion increases mainly when glucose is elevated. This property is often described as lowering the chance of hypoglycaemia when the compound is used alone. Other glucose-lowering agents used at the same time can still cause low blood glucose.
Long-term storage is usually at minus 20 to minus 80 degrees Celsius in a sealed, desiccated container. Working aliquots can be held briefly at 2 to 8 degrees Celsius.