A practical reference on GLP-1 receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-14. Anything still debated is marked as such rather than presented as settled.
脂肪酸侧链的存在使该肽与血浆白蛋白结合能力增强,从而延长循环半衰期,支持每周一次给药的用药间隔。白蛋白结合同时改变组织分布特征,减慢肾脏清除速度。该设计思路在多种长效肽类药物中被反复采用,属于既定的药代动力学策略。
该化合物的名称与结构由国际非专利名称体系统一维持,不同文献中出现的同义写法主要在拼写顺序或盐形式描述上不同。研究者通常通过受体结合实验、细胞内环磷酸腺苷积累测定以及动物模型来确认其双激动活性。相当一部分分子层面的细节——例如两条受体通路之间的信号交叉作用——尚处于开放问题状态。
当前公开资料把 tirzepatide 归为肠促胰素类受体双重激动剂。它并非激素天然变体,而是经过序列改造的工程化肽。其分子量、等电点与疏水性等基础参数已在药典和化学数据库中收录,可作为分析检测和质量研究的参照。
纯度评估通常综合反相色谱、体积排阻色谱与质谱三方面信息:前者反映疏水性杂质,后者反映聚集体,质谱则确认分子量与主要降解产物。有关降解途径的完整图谱——例如脱酰胺、氧化与水解各占多大比例——在不同储存条件下仍有差异,属于需要逐案验证的问题。
质量控制环节关注外观、含量、纯度、有关物质、水分与微生物限度等项目。检测结果需要有对照品和系统适用性数据支持,单次测定不足以判定批次的稳定性。实验室之间方法转移时,色谱柱品牌与梯度差异常导致保留时间漂移,因此方法验证十分必要。
| Property | Value | Notes |
|---|---|---|
| 分子类型 | 合成修饰肽 | 39 个氨基酸,含脂肪酸侧链 |
| 受体靶点 | GIP 与 GLP-1 受体 | 双重激动剂 |
| 分子量 | 约 4.8 kDa | 以游离肽计 |
| 外观 | 白色至类白色粉末 | 冻干形态常见 |
| 溶解性 | 可溶于水及水性缓冲液 | 溶解后宜低温保存 |
Tirzepatide is a synthetic peptide composed of 39 amino acids. It acts as a dual agonist at two incretin receptors, the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. The molecule was designed by modifying the native sequence of glucose-dependent insulinotropic polypeptide to improve metabolic stability and extend its circulation time. Its structure includes several non-natural amino acid residues and a fatty acid side chain. These features distinguish it from earlier single-receptor incretin analogs studied in the same period.
The compound first appeared in the scientific literature as an investigational agent for type 2 diabetes. Clinical development proceeded through phase 1, phase 2, and phase 3 programs that measured glycemic control as a primary endpoint while recording body weight as a secondary outcome. Regulatory approval in the United States followed in 2022 for glycemic control, and a separate indication for chronic weight management was added later. Subsequent trials have examined cardiovascular outcomes in adults with elevated cardiovascular risk. Debates continue over how much of the observed effect derives from each receptor arm.
Structural work on the molecule centers on a C20 fatty diacid moiety attached through a linker to the peptide backbone. This side chain promotes reversible binding to serum albumin, which slows renal clearance and supports a prolonged action profile. The peptide backbone incorporates aminoisobutyric acid substitutions that limit recognition by digestive enzymes. Together these modifications produce a molecule that is stable enough for subcutaneous delivery but still dependent on careful manufacturing control. Analytical characterization of the active pharmaceutical ingredient typically follows the conventions used for other synthetic peptides.
Peptide active ingredients of this type are typically supplied as lyophilized powder because the dry form resists hydrolysis during transport. The material is hygroscopic, so vials are usually equilibrated to room temperature before opening to avoid condensation on the solid. Repeated freeze-thaw cycles can promote aggregation and are generally avoided by aliquoting stock into single-use portions. Personnel handling the powder work in controlled environments to limit inhalation of fine particles. Written procedures usually specify these steps rather than leaving them to individual judgment.
Long-term storage of the solid generally relies on temperatures at or below minus twenty degrees Celsius, while short-term working stocks may be held refrigerated. Light exposure is limited because photodegradation can alter side chains over extended periods. Solutions prepared for analysis are less stable than the dry powder and are typically used within the same working day. Buffer choice matters, since some aqueous conditions favor deamidation or oxidation at specific residues. Stability data are usually generated under defined accelerated conditions and then extrapolated with stated assumptions.
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.
Identity and purity are assessed by reversed-phase high-performance liquid chromatography, with mass confirmation by electrospray ionisation mass spectrometry. Peptide mapping after enzymatic digestion verifies the primary sequence. Size-exclusion chromatography quantifies aggregates, while circular dichroism provides a secondary-structure fingerprint. Bioanalytical quantification in plasma uses immunoassay or LC-MS/MS. Reported purity for research-grade lots is commonly 95 percent or higher, and residual water content is checked by Karl Fischer titration.
As a peptide, tirzepatide is handled as a lyophilised solid in research settings and as a preserved solution in finished products. Aqueous solubility is pH dependent and reaches a minimum near the isoelectric point, which lies close to pH 5.4. Stock solutions are typically prepared in neutral or slightly basic buffer to limit precipitation. The solid is hygroscopic and should be equilibrated to room temperature before opening so that condensation does not form on the powder surface.
Recommended storage for reference material is a freezer at approximately -20 degrees Celsius, protected from light and moisture. Commercial injectable presentations are stored refrigerated between 2 and 8 degrees Celsius and must not be frozen. Product labelling generally permits a limited period at controlled room temperature once dispensed, with the exact window depending on the presentation. Repeated temperature cycling is avoided because it can promote aggregation or deamidation of the peptide chain.
== Research == Ala-Kokko's research focuses on collagen in cartilage, and connective tissue disorders. She has, with her research group, succeeded in identifying the errors in cartilage collagen that lead to the development of osteoarthritis and diseases of the vertebrae, amongst others. Her results have assisted in the diagnosis and care of patients, as well as improvements to the way in which these diseases are treated. She has published about 160 articles based on her research, and she has been awarded five patents.
==== Scoring systems ==== To better understand how severe cachexia is in each person, doctors use scoring systems like the Cachexia Staging Score and Cachexia Score. The Cachexia Staging Score (CSS) looks at weight loss, muscle function, appetite loss, and lab test results to categorize people into four stages: non-cachexia, pre-cachexia, cachexia, and refractory cachexia. Those in more advanced stages have less muscle mass, more frequent age-related muscle loss, worse symptoms, poorer quality of life, as well as shorter survival periods.
"... It has been said, and is still being obstinately repeated by anti-Zionists again and again, that Zionism aims at the creation of an independent "Jewish State". But this is wholly fallacious. The "Jewish State" was never part of the Zionist programme. The "Jewish State" was the title of Herzl's first pamphlet, which had the supreme merit of forcing people to think. This pamphlet was followed by the first Zionist Congress, which accepted the Basle programme—the only programme in existence." At the San Remo conference of 19–26 April 1920, the principal Allied and Associated Powers mandated the creation of a Jewish homeland. Britain officially committed itself to the objective set out in the Balfour Declaration by insisting on its forming the basis of the Mandate for Palestine, which was formally approved by the League of Nations in June 1922. The preamble of the Mandate declared:
Sources: en.wikipedia.org
== Apologies == On May 21, 2001, the National Assembly of France passed the Taubira law, recognizing slavery as a crime against humanity. Apologies on behalf of African nations, for their role in trading their countrymen into slavery, remain an open issue since slavery was practiced in Africa even before the first Europeans arrived and the Atlantic slave trade was performed with a high degree of involvement of several African societies. The black slave market was supplied by well-established slave trade networks controlled by local African societies and individuals.
== Corruption == Corruption Perceptions Index 2019: Thailand ranked 101 of 180 nations (1=cleanest; 180=most corrupt). Other ASEAN nations ranked: Singapore, 4; Brunei, 35; Malaysia, 51; Indonesia, 85; Vietnam, 96; Philippines, 113; Myanmar, 130; Laos, 130 (tie); and Cambodia, 162. Corruption Perceptions Index 2018: Thailand ranked 99 of 180 nations (1=clean; 180=most corrupt). Other ASEAN nations ranked: Singapore, 3; Brunei, 31; Malaysia, 61; Indonesia, 89; Philippines, 99 (tie); Vietnam, 117; Myanmar, 132; Laos, 132 (tie); and Cambodia, 161. Corruption Perceptions Index 2017: Thailand ranked 96 of 180 nations (1=clean; 180=most corrupt). Other ASEAN nations ranked: Singapore, 6; Brunei, 32; Malaysia, 62; Indonesia, 96 (tie); Vietnam, 107; Philippines, 111; Myanmar, 130; Laos, 135; and Cambodia, 161. Corruption Perceptions Index 2016: Thailand ranked 101 of 176 nations (1=clean; 176=most corrupt). Other ASEAN nations ranked: Singapore, 7; Brunei, 41; Malaysia, 56; Indonesia, 90; Philippines, 101; Vietnam, 113; Laos, 123; Myanmar, 136; and Cambodia, 156. Corruption Perceptions Index 2015: Thailand ranked 76 of 167 nations (1=clean; 167=most corrupt) on this annual survey. Other ASEAN nations were ranked: Singapore, 8; Malaysia, 54; Indonesia, 88; Philippines, 95; Vietnam, 112; Laos, 139; Myanmar, 147; and Cambodia, 150. Corruption Perceptions Index 2014: Transparency International's CPI 2014 ranked Thailand 85 of 174 countries (1=clean; 174=most corrupt).
Granzymes are serine proteases released by cytoplasmic granules within cytotoxic T cells and natural killer (NK) cells. They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infected with viruses or bacteria. Granzymes also kill bacteria and inhibit viral replication. In NK cells and T cells, granzymes are packaged in cytotoxic granules along with perforin. Granzymes can also be detected in the rough endoplasmic reticulum, golgi complex, and the trans-golgi reticulum. The contents of the cytotoxic granules function to permit entry of the granzymes into the target cell cytosol. The granules are released into an immune synapse formed with a target cell, where perforin mediates the delivery of the granzymes into endosomes in the target cell, and finally into the target cell cytosol. Granzymes are part of the serine esterase family. They are closely related to other immune serine proteases expressed by innate immune cells, such as neutrophil elastase and cathepsin G. Granzyme B activates apoptosis by activating caspases (especially caspase-3), which cleaves many substrates, including caspase-activated DNase to execute cell death. Granzyme B also cleaves the protein Bid, which recruits the proteins Bax and Bak to change the membrane permeability of the mitochondria, causing the release of cytochrome c (which is one of the parts needed to activate caspase-9 via the apoptosome), Smac/Diablo and Omi/HtrA2 (which suppress the inhibitor of apoptosis proteins (IAPs)), among other proteins.
Sources: en.wikipedia.org
=== Optical activity === Whether in water or the solid form, d-(+)-glucose is dextrorotatory, meaning it will rotate the direction of polarized light clockwise as seen looking toward the light source. The effect is due to the chirality of the molecules, and indeed the mirror-image isomer, l-(−)-glucose, is levorotatory (rotates polarized light counterclockwise) by the same amount. The strength of the effect is different for each of the five tautomers. The d- prefix does not refer directly to the optical properties of the compound. It indicates that the C-5 chiral center has the same handedness as that of d-glyceraldehyde (which was so labeled because it is dextrorotatory). The fact that d-glucose is dextrorotatory is a combined effect of its four chiral centers, not just of C-5; some of the other d-aldohexoses are levorotatory. The conversion between the two anomers can be observed in a polarimeter since pure α-d-glucose has a specific rotation angle of +112.2° mL/(dm·g), pure β-d-glucose of +17.5° mL/(dm·g). When equilibrium has been reached after a certain time due to mutarotation, the angle of rotation is +52.7° mL/(dm·g). By adding acid or base, this transformation is much accelerated. The equilibration takes place via the open-chain aldehyde form.
== Treatment == Treatment is most effective when it is early and aggressive. Patients may face issues such as poor nutrition, infections, and skin breakdown. Immobility can lead to pressure ulcers, muscle contractions, and the formation of blood clots in the legs (deep vein thrombosis) and the lungs (pulmonary embolism). Other complications also include the development of pneumonia and neuroleptic malignant syndrome. The first choice of treatment for catatonia is benzodiazepines, particularly lorazepam, which may be used as a diagnostic tool via the "lorazepam challenge". Patients are given a dose of lorazepam and their condition monitored; if there is an improvement within minutes, catatonia is likely. Patients who require a rapid response or do not respond to benzodiazepines may undergo a course of electroconvulsive therapy. This has been shown to produce favorable response rates, particularly in patients with malignant catatonia, and often succeeds where medication does not. Catatonia may be caused by external factors such as medical problems, side effects of certain medications, and psychiatric disorders such as depression and schizophrenia. The cause can affect treatment and outcomes: for example, catatonia associated with schizophrenia may respond less effectively to benzodiazepines.
In January 1975, the Presidency of the Socialist Republic of Serbia requested a revision of constitutional solutions with explanation that the constitution divided the republic into three parts, thus preventing Serbia from exercising its "historic right to a nation state in the Yugoslav federation". Furthermore, the study Marković requested was completed in 1977 and was named The Blue Book. Although there were differing opinions in the state leadership on the position of the provinces – for example, Edvard Kardelj supported the demands of Serbian leaders – the result of the arbitration was the conclusion that the position of the provinces within Serbia should not be changed. The Federal leadership, led by Tito, believed that the constitutional solution from 1974 could satisfy all the claims of the Socialist Republic of Serbia, but also respect the specifics and special interests of the autonomous provinces. Although the conflict was (temporarily) pacified in this way, the issue remained unresolved. For most of its existence in the SFRY, Serbia was loyal and generally subordinate to the federal government. This changed after the death of Josip Broz Tito in 1980, when Albanian, as well as Serbian nationalism in Kosovo arose. In 1981, major protests erupted in Kosovo demanding the status of republic. The League of Communists was split on how to respond. At the same time, an economic crisis in Yugoslavia started. The leaders of the country were unable to carry out any reforms due to the political instability.
Sources: en.wikipedia.org
它属于合成修饰肽,同时激动 GIP 与 GLP-1 两种肠促胰素受体。这类分子通常被称为双重肠促胰素受体激动剂,与选择性 GLP-1 激动剂在靶点范围上不同。
分子上的脂肪酸侧链使其与血浆白蛋白结合增强,显著延长循环半衰期。半衰期延长后,稳定血药浓度可在较长的给药间隔内维持,因此常见用法为每周一次。
同时激活两条肠促胰素通路可能在胰岛素分泌、胃排空和食欲调节上产生叠加效应。与单靶点相比,临床研究中观察到的血糖与体重变化幅度通常更明显,但各通路的具体贡献比例尚无定论。
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。