The short version of GLP-1 receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-05. Anything still debated is marked as such rather than presented as settled.
溶解操作一般使用注射用水或适宜的水性缓冲液，必要时加入少量助溶剂以改善溶解速度，但应避免剧烈涡旋振荡，因为剪切力可能促进聚集。配制后的溶液在冷藏条件下的稳定时间通常短于固体形态，具体时限取决于浓度、缓冲体系与容器材质。是否加入防腐成分，则取决于用途是否为多次取样。
定量分析的主流方法是反相高效液相色谱联用紫外或质谱检测，利用肽在疏水固定相上的保留行为确定纯度与含量。对于生物基质中的浓度测定，常采用液相色谱串联质谱，并配合固相萃取或蛋白沉淀进行样品前处理。免疫分析法也可使用，但可能受到结构相关肽的交叉反应干扰。
Clinical research programs have evaluated tirzepatide in adults with type 2 diabetes and in adults with obesity or excess weight. Trials generally reported reductions in glycated hemoglobin and body weight across treatment periods of several months. Since these studies enrolled defined populations under controlled conditions, the findings describe group averages rather than individual outcomes. Open questions include the durability of effects after treatment stops, variation among subgroups, and the long-term consequences of sustained dual receptor stimulation. Published trial summaries should be consulted for exact measurements rather than secondary accounts.
Tirzepatide is a synthetic peptide built from 39 amino acid residues. Its backbone derives from the native glucose-dependent insulinotropic polypeptide sequence, altered at several positions to resist enzymatic cleavage. A fatty diacid group attached through a linker extends plasma residence time by promoting reversible binding to serum albumin. The molecule carries a net negative charge near physiological pH and has a reported molecular weight close to 4813 daltons. These features separate it from shorter incretin analogs and account for its prolonged dosing interval.
Pharmacologically, tirzepatide activates two distinct G protein-coupled receptors: the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Binding at each target triggers cyclic AMP accumulation and downstream signaling in pancreatic beta cells, adipose tissue and the central nervous system. Because the two pathways overlap only partially, the combined effect on insulin secretion, glucagon suppression and appetite signaling differs from that of selective single-receptor compounds. Affinity is not equal across the two targets, and the clinical meaning of that imbalance remains an area of active study.
| Property | Value | Notes |
|---|---|---|
| 储存温度 | 2 至 8 摄氏度 | 固体粉末，避光密封 |
| 外观 | 白色至类白色冻干粉 | 溶解后为澄清至微乳光 |
| 溶解性 | 易溶于水性缓冲液 | 避免剧烈振荡 |
| 常规纯度方法 | 反相高效液相色谱 | 紫外或质谱检测 |
| 定量方法 | 液相色谱串联质谱 | 配合固相萃取前处理 |
Structure-activity work shows that fatty acid length, linker chemistry and the position of acylation all influence albumin affinity and receptor potency. Plasma protein binding exceeds 99 percent, which restricts distribution and slows renal clearance. Degradation proceeds largely through general proteolysis and fatty acid oxidation rather than cytochrome P450 metabolism, so exposure to common oxidative drug interactions is limited. Whether these clearance routes vary meaningfully between individuals is not fully established.
The molecule is a synthetic 39-amino-acid peptide whose backbone derives from the sequence of human glucose-dependent insulinotropic polypeptide, with several substitutions that raise metabolic stability and shift receptor preference. A C20 fatty diacid is attached through a short linker to a lysine side chain, a modification that increases binding to serum albumin. The reported monoisotopic mass is approximately 4813 Da. Near neutral pH the peptide carries a net negative charge, and the lipid tail makes the molecule markedly more hydrophobic than the unmodified parent sequence.
Dual agonism at the GIP and GLP-1 receptors underlies the observed pharmacology. Activation of GLP-1 receptors raises glucose-dependent insulin release, lowers glucagon secretion, slows gastric emptying and reduces appetite. GIP receptor activation contributes additional effects on adipose tissue and on energy balance, and the combined action on appetite appears larger than either pathway alone in animal models. Signalling bias and the relative contribution of each receptor arm to weight-related effects remain areas of active investigation.
Degradation pathways for tirzepatide include deamidation, oxidation, and aggregation, which are common for therapeutic peptides. These processes can be monitored by size-exclusion chromatography (SEC) for aggregates and ion-exchange chromatography for charge variants. Forced degradation studies under acidic, basic, oxidative, and thermal stress help identify potential impurities. The exact stability profile depends on formulation, concentration, and container-closure system.
Analytical characterization of tirzepatide typically employs reversed-phase high-performance liquid chromatography (RP-HPLC) for purity assessment and peptide mapping. Mass spectrometry, often coupled with electrospray ionization, confirms molecular weight and sequence integrity. Amino acid analysis and capillary electrophoresis may also be used to detect impurities or degradation products. These methods are essential for batch release and stability studies.
Storage recommendations for tirzepatide generally specify refrigeration at 2–8 °C to maintain stability. The peptide should be protected from light and kept in its original packaging to prevent aggregation or adsorption. Freezing is not recommended because freeze-thaw cycles can cause aggregation or precipitation. Once dispensed, storage conditions and in-use periods follow product-specific labeling, which may allow room temperature storage for a limited time.
Receptor activation by tirzepatide raises intracellular cyclic AMP through Gs-coupled signalling at both targets. At the GLP-1 receptor the downstream effect includes glucose-dependent insulin release, suppressed glucagon secretion, delayed gastric emptying, and reduced appetite signalling in the hypothalamus. GIP receptor engagement adds insulinotropic activity and appears to influence lipid handling in adipose tissue. Because both receptors are stimulated at the same time, the pharmacological profile differs from that of selective GLP-1 receptor agonists, and the relative contribution of each arm remains an area of active investigation.
Clinical development proceeded through large phase 3 programmes in type 2 diabetes and in obesity or overweight with at least one weight-related comorbidity. Regulatory approvals followed in several jurisdictions for both indications. Weekly subcutaneous dosing reflects an elimination half-life of roughly five days. Open questions include the durability of metabolic effects after treatment stops, long-term cardiovascular and hepatic outcomes beyond completed trials, and whether the dual mechanism confers benefits independent of total receptor occupancy. Published literature continues to expand on these points. Substantial uncertainty remains about interindividual variability in response.
Tirzepatide is a synthetic linear peptide of 39 amino acids that acts as a dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. Its sequence derives from native GIP but incorporates non-natural residues and a C20 fatty diacid moiety linked to a lysine side chain. The lipophilic chain promotes albumin binding, which slows renal clearance and extends circulation time. The unmodified peptide has a molecular formula of C225H348N48O68 and a molecular mass near 4,813 daltons.
Strigolactones (SLs) were originally discovered through studies of the germination of the parasitic weed Striga lutea. It was found that the germination of Striga species was stimulated by the presence of a compound exuded by the roots of its host plant. It was later shown that SLs that are exuded into the soil also promote the growth of symbiotic arbuscular mycorrhizal (AM) fungi. More recently, another role of SLs was identified in the inhibition of shoot branching. This discovery of the role of SLs in shoot branching led to a dramatic increase in the interest in these hormones, and it has since been shown that SLs play important roles in leaf senescence, phosphate starvation response, salt tolerance, and light signalling.
== Early life and education == Otto Hahn was born in Frankfurt am Main on 8 March 1879, the youngest son of Heinrich Hahn, a prosperous glazier and founder of the Glasbau Hahn company, and Charlotte Hahn (née Giese). He had an older half-brother Karl, his mother's son from her previous marriage, and two older brothers, Heiner and Julius. The family lived above his father's workshop. The younger three boys were educated at the Klinger Oberrealschule in Frankfurt. At the age of 15, Otto began to take a special interest in chemistry, and carried out simple experiments in the laundry room of the family home. His father wanted him to study architecture, as he had built or acquired several residential and business properties, but Otto persuaded him that his ambition was to become an industrial chemist. In 1897, after passing his Abitur, Hahn began to study chemistry at Marburg University. His subsidiary subjects were mathematics, physics, mineralogy and philosophy. Hahn joined the Students' Association of Natural Sciences and Medicine, a student fraternity and a forerunner of today's Landsmannschaft Nibelungi (Coburger Convent der akademischen Landsmannschaften und Turnerschaften). He spent his third and fourth semesters at the Ludwig-Maximilians-Universität München, studying organic chemistry under Adolf von Baeyer, physical chemistry under Wilhelm Muthmann, and inorganic chemistry under Karl Andreas Hofmann. In 1901, Hahn received his doctorate at Marburg University for a dissertation entitled "On Bromine Derivates of Isoeugenol", a topic in classical organic chemistry.
=== Youth councils === Under the terms of the Local Government Act 2002, district councils have to represent the interests of their future communities and consider the views of people affected by their decisions. To fulfill that requirement and give young people a say in the decision-making process, many councils have a youth council. In late December 2023, the Ashburton District Council scrapped their youth council, stating they could engage better with younger people online and describing the current youth council as "a youth club where they ate pizza." In early January 2024, the Gore District Council opted to restructure its youth council and ruled out dismantling it. In April 2024, the Whanganui District Council proposed scrapping its youth council by June 2024 as part of budget saving measures.
== Medical uses == ACE inhibitors were initially approved for the treatment of hypertension and can be used alone or in combination with other anti-hypertensive medications. Later, they were found useful for other cardiovascular and kidney diseases including:
=== Parkinson's disease === In the case of Parkinson's disease, a series of observational studies that consistently suggest a possibly substantial reduction in risk among smokers (and other consumers of tobacco products) has led to longstanding interest among epidemiologists. Non-biological factors that may contribute to such observations include reverse causality (whereby prodromal symptoms of Parkinson's disease may lead some smokers to quit before diagnosis), and personality considerations (people predisposed to Parkinson's disease tend to be relatively risk-averse, and may be less likely to have a history of smoking). Possible existence of a biological effect is supported by a few studies that involved low levels of exposure to nicotine without any active smoking. Another study considered a possible role of nicotine in reducing Parkinson's risk: nicotine stimulates the dopaminergic system of the brain, which is damaged in Parkinson's disease, while other compounds in tobacco smoke inhibit MAO-B, an enzyme which produces oxidative radicals by breaking down dopamine. A data-driven hypothesis that long-term administration of very low doses of nicotine (for example, in an ordinary diet) might provide a degree of neurological protection against Parkinson's disease remains open as a potential preventive strategy.
Sources: en.wikipedia.org
are calculated for a short time frame, and the matrices for longer periods of time are calculated by assuming mutations follow a Markov chain model. The base unit of time for the PAM matrices is the time required for 1 mutation to occur per 100 amino acids, sometimes called 'a PAM unit' or 'a PAM' of time. This is precisely the duration of mutation assumed by the PAM1 matrix. The constant
Pascal's law (also Pascal's principle or the principle of transmission of fluid-pressure) is a principle in fluid mechanics that states that a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. The law was established by French mathematician Blaise Pascal in 1653 and published in 1663.
Natural killer T cells (NKT cells – not to be confused with natural killer cells of the innate immune system) bridge the adaptive immune system with the innate immune system. Unlike conventional T cells that recognize protein peptide antigens presented by major histocompatibility complex (MHC) molecules, NKT cells recognize glycolipid antigens presented by CD1d. Once activated, these cells can perform functions ascribed to both helper and cytotoxic T cells: cytokine production and release of cytolytic/cell killing molecules. They are also able to recognize and eliminate some tumor cells and cells infected with herpes viruses.
==== Books in which Jung is a character in the narrative ==== Laurens van der Post was an Afrikaner author who claimed to have had a 16-year friendship with Jung, from which books and a film were created about Jung. The accuracy of van der Post's claims about his relationship to Jung has been questioned. In his novel The World is Made of Glass (1983), Morris West gives a fictional account of one of Jung's cases, placing the events in 1913. According to the author's note, the novel is "based upon a case recorded, very briefly, by Carl Gustav Jung in his autobiographical work Memories, Dreams, Reflections". Pilgrim, a supernatural novel in which Jung is a character. Possessing the Secret of Joy, a novel in which Jung is a therapist character. The Interpretation of Murder, a novel focused on Sigmund Freud in which he solves a murder in New York City.
They may move along microfilament tracks, and the fact that the microfilament mesh changes shape to form a honeycomb structure surrounding the chloroplasts after they have moved suggests that microfilaments may help to anchor chloroplasts in place.
Sources: en.wikipedia.org
CO(NH2)2 + H2O → 2 NH3 + CO2 Being a solid highly soluble in water (1200 g/L at 25 °C (77 °F)), urea is much easier and safer to handle and store than the more irritant, caustic and hazardous ammonia, so it is the reactant of choice. Trucks and cars using these catalytic converters need to carry a supply of diesel exhaust fluid, also sold as AdBlue, a solution of urea in water.
Further studies demonstrate that supportive settings significantly reduce the likelihood of adverse reactions, including panic, paranoia, or psychological distress. Positive therapeutic outcomes are strongly correlated with the participant's trust in the environment and the facilitators.
The other method involves transesterification of sucrose and fatty acid methyl ester using sodium methoxide as a basic catalyst. The by-product methanol can be removed via distillation to drive the equilibrium to favor sucrose esters.
CPPs found applications as transporters of contrast agents across plasma membranes. These contrast agents are able to label the tumor cells, making the compounds important tools in cancer diagnosis; they are also used in in vivo and in vitro cellular experiments. The most important classes of CPP are isolated from viruses, such as TAT (transactivated-transcription) derived from HIV-1, penetratin, and transportan. The most widely used CPPs are based on TAT derivatives. TAT is an arginine-rich CPP. Several improvements for this substrate includes the usage of unnatural β or γ amino acids. This strategy offers multiple advantages, such resistance to proteolytic degradation, a natural degradation process by which peptide bonds are hydrolyzed to amino acids. Unnatural acid insertion in the peptide chain has multiple advantages. It facilitates the formation of stable foldamers with distinct secondary structure. β-Peptides are conformationally more stable in aqueous solution than naturally occurring peptides, especially for small chains. The secondary structure is reinforced by the presence of a rigid β-amino acid, which contains cyclohexane or cyclopentane fragments. These fragments generate a more rigid structure and influence the opening angle of the foldamer. These features are important for new peptide design. Helical β-peptides mimic antimicrobial activities of host defense peptides. This feature requires the orientation of cationic –hydrophilic on one side, and hydrophobic residues on the other side of the helix.
Vitamin C was discovered in 1912, isolated in 1928 and synthesized in 1933, making it the first vitamin to be synthesized. Shortly thereafter Tadeus Reichstein succeeded in synthesizing the vitamin in bulk by what is now called the Reichstein process. This made possible the inexpensive mass-production of vitamin C. In 1934, Hoffmann–La Roche bought the Reichstein process patent, trademarked synthetic vitamin C under the brand name Redoxon, and began to market it as a dietary supplement. In 1907, a laboratory animal model which would help to identify the antiscorbutic factor was serendipitously discovered by the Norwegian physicians Axel Holst and Theodor Frølich, who when studying shipboard beriberi, fed guinea pigs their test diet of grains and flour and were surprised when scurvy resulted instead of beriberi. Unknown at that time, this species did not make its own vitamin C (being a caviomorph), whereas mice and rats do. In 1912, the Polish biochemist Casimir Funk developed the concept of vitamins. One of these was thought to be the anti-scorbutic factor. In 1928, this was referred to as "water-soluble C", although its chemical structure had not been determined.
Sources: en.wikipedia.org
建议在低温、避光、干燥环境中密封保存，常见条件为 2 至 8 摄氏度，长期存放可置于更低温度。应避免反复冻融，并尽量减少容器开启次数。
溶解后的稳定时间通常短于固体形态，受浓度、缓冲液和容器材质影响。冷藏条件下一般只能维持较短时间，具体期限应通过实际稳定性实验确认。
反相高效液相色谱用于纯度与含量测定，液相色谱串联质谱用于生物基质中的定量，体积排阻色谱用于检测聚集体。多种方法结合才能较完整地表征样品。
It is a synthetic peptide that activates both the GIP and GLP-1 receptors, making it a dual agonist. Approved products are given by injection rather than by mouth. It is not a small molecule and does not belong to the older sulfonylurea or thiazolidinedione families.