This is a working overview of 肠促胰素, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-01-21 and is reviewed periodically as new material appears.
Tirzepatide 是一种由 39 个氨基酸组成的合成肽，分子结构上以 GIP 序列为骨架并引入脂肪酸侧链修饰，使其能够同时与葡萄糖依赖性促胰岛素多肽（GIP）受体和胰高血糖素样肽-1（GLP-1）受体结合。这种双重激动特性使它在同类肽类药物中区别于选择性 GLP-1 受体激动剂。该分子最早由一家制药公司在 2010 年代报道，随后进入糖尿病与体重管理领域的临床研究。
在生理层面，GIP 与 GLP-1 均为肠道内分泌细胞分泌的肠促胰素，进食后参与胰岛素分泌调节与胃排空抑制。Tirzepatide 通过同时激活这两条信号通路，使胰岛素分泌的葡萄糖依赖性增强，并延缓冲胃排空、降低食欲信号。与单一 GLP-1 激动相比，双靶点作用在血糖控制和体重变化上的效应幅度更大，但具体贡献比例仍在研究之中。
Identity and purity are usually established with reversed-phase high-performance liquid chromatography for the main peak and with mass spectrometry for the observed molecular mass. Peptide mapping after enzymatic digestion confirms the primary sequence, while amino acid analysis provides a quantitative composition check. Size-exclusion chromatography and ion-exchange chromatography are used to look for aggregates and charge variants. Water content, residual solvents, and counter-ion content are measured separately, since a lyophilised powder is often reported on an as-is basis unless a correction is applied.
Research-grade material circulates through suppliers that differ widely in documentation and testing practice, so a certificate of analysis is a starting point rather than proof of quality. Independent verification typically repeats chromatographic purity and mass confirmation on the received lot, and compares results against a retained reference standard. Regulatory status varies by jurisdiction, and a substance cleared as a medicine is not interchangeable with a research chemical of the same name. Open questions include how closely non-pharmaceutical lots match approved material in impurity profile and in aggregate content.
| 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 |
Regulatory and quality discussions place the peptide within established guidance for synthetic peptides and biologics. Forced degradation studies, in which samples are exposed to heat, acid, base, peroxide, and light, identify likely degradation products and validate the selectivity of analytical methods. Reference standards allow comparison across laboratories and production batches. Purity specifications reported in the literature usually combine chromatographic purity with mass confirmation. Which impurity thresholds are meaningful for long-term behavior is still debated, and no single universal specification has been adopted across all jurisdictions.
Routine characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity assessment, usually with ultraviolet detection near 214 nanometers. Intact mass measurement by liquid chromatography coupled to mass spectrometry confirms molecular identity against a theoretical value. Sequence-level confirmation uses enzymatic digestion followed by tandem mass spectrometry, an approach known as peptide mapping. Amino acid analysis gives an independent check on composition. Circular dichroism spectra are used to estimate helical content in aqueous buffer.
Stability depends strongly on physical form. The dry powder is generally regarded as stable for extended periods when held at or below minus twenty degrees Celsius in a sealed, desiccated container. In solution, degradation pathways include deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation. Reaction rates for these pathways rise with temperature. Repeated freezing and thawing of solutions promotes aggregation, and light exposure can accelerate some oxidative changes. Buffer composition and pH influence which pathway dominates at a given temperature.
Tirzepatide activates both the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor, making it a dual agonist rather than a selective agent. Engagement of the GLP-1 receptor is linked to glucose-dependent insulin release, slower gastric emptying, and reduced appetite signalling. The relative contribution of the GIP arm remains an active research question; proposed roles include improved insulin sensitivity and altered adipose tissue handling. Receptor occupancy studies suggest the molecule interacts with both targets at circulating concentrations achieved during therapy.
Development began in the 2010s, when researchers modified a GIP-based scaffold to add GLP-1 activity and then attached the fatty diacid to lengthen its half-life. Clinical evaluation proceeded through large phase 3 programmes in type 2 diabetes and in obesity, and regulators in the United States cleared the compound for type 2 diabetes in 2022 and for chronic weight management in 2023. Several cardiovascular and metabolic outcome studies are still reporting, so the picture of long-term benefit and risk is incomplete. Approvals in other regions followed on different timelines.
=== EC 1.6.2 With a heme protein as acceptor === EC 1.6.2.1: now EC 1.6.99.3 NADH dehydrogenase EC 1.6.2.2: cytochrome-b5 reductase EC 1.6.2.3: deleted EC 1.6.2.4: NADPH—hemoprotein reductase EC 1.6.2.5: NADPH—cytochrome-c2 reductase EC 1.6.2.6: leghemoglobin reductase
These are known as 'targeted primary health care outlet'—as these outlets primarily target people who inject drugs and/or 'low-threshold health care outlet'—as these reduce common barriers clients often face when they try to access health care from the conventional health care outlets. For accessing sterile injecting equipment clients frequently visit NSP outlets, and for receiving pharmacotherapy (e.g. methadone, buprenorphine) they visit OST clinics; these frequent visits are used opportunistically to offer much needed health care. These targeted outlets have the potential to mitigate clients' perceived barriers to access to healthcare delivered in traditional settings. The provision of accessible, acceptable and opportunistic services which are responsive to the needs of this population is valuable, facilitating a reduced reliance on inappropriate and cost-ineffective emergency department care.
== Medical uses == In the European Union, afamelanotide is indicated for the prevention of phototoxicity in adults with erythropoietic protoporphyria. In the United States, afamelanotide is indicated for increasing pain-free light exposure in adults with a history of reactions to light (phototoxicity) from erythropoietic protoporphyria.
karyorrhexis The fragmentation and degeneration of the nucleus of a dying cell, during which the nuclear envelope is destroyed and the contents of the nucleus, including chromatin, are dispersed throughout the cytoplasm and degraded by enzymes. Karyorrhexis is usually preceded by pyknosis and may occur as a result of apoptosis, cellular senescence, or necrosis.
Sources: en.wikipedia.org
Treating any other infections prior to surgery also reduces the risks of a postoperative wound infection. Examples of these pre-existing infections are urinary tract infection or lower reproductive system infection. Removing the hair where the skin will be cut helps to reduce the risk of complications, though shaving is not considered to be appropriate and instead depilatories are used. Those who come in contact with the person who is receiving the surgery clean and disinfect their own skin surfaces. The patient's skin is also cleaned, scrubbed and treated with antiseptics. Patients undergoing surgery often receive antibiotics before surgery. During the surgery, there are several precautions that can be taken to reduce the risk of postoperative wound complications. These are: minimizing traffic in the operating room, providing adequate ventilation, not closing wounds that are infected, minimize tissue handling, re-administer prophylactic antibiotics if large amounts of fluid are lost during surgery, and keeping the patient warm. Lately, studies have highlighted new preventative measures of avoiding repeated reprocessing and intraoperatively guarding the implants in the sterile-field, for surgeries implanting single-use devices such as orthopedic and spine surgeries. The risk of complications after surgery can be reduced by: maintaining blood glucose levels in the normal range and constant evaluation of surgical site infection.
The president had only joined the cry of "Down with the Republicans!" in Montalembert in the hope of effecting a revision of the constitution without having recourse to a coup d'état. His concessions only increased the boldness of the monarchists, who had only accepted Louis-Napoléon as president in opposition to the Republic and as a step in the direction of the monarchy. A conflict was now inevitable between his personal policy and the majority of the Chamber, who were divided into legitimists and Orléanists in spite of the death of Louis-Philippe in August 1850. Louis-Napoléon exploited their projects for a restoration of the monarchy, which he knew to be unpopular in the country, and which gave him the opportunity of furthering his own personal ambitions. From 8 August to 12 November 1850 he went about France stating the case for a revision of the constitution in speeches which he varied according to each place; he held reviews, at which cries of "Vive Napoléon!" showed that the army was with him; he superseded General Changarnier, on whose arms the parliament relied for the projected monarchical coup d'état; he replaced his Orléanist ministry with obscure men devoted to his own cause, such as Morny, Fleury and Persigny, and gathered round him officers of the African army, broken men like General Saint-Arnaud; in fact he practically declared open war.
Following the Christianization of the Roman Empire in late antiquity, vegetarianism practically disappeared from Europe, as it did elsewhere, except in India. Several orders of monks in medieval Europe restricted or banned the consumption of meat for ascetic reasons, but none of them eschewed fish. Moreover, the medieval definition of "fish" included such animals as seals, porpoises, dolphins, barnacle geese, puffins, and beavers. Vegetarianism re-emerged during the Renaissance, becoming more widespread in the 19th and 20th centuries. In 1847, the first Vegetarian Society was founded in the United Kingdom; Germany, the Netherlands, and other countries followed. In 1886, the vegetarian colony Nueva Germania was founded in Paraguay, though its vegetarian aspect would prove short-lived. The International Vegetarian Union, an association of the national societies, was founded in 1908. In the Western world, the popularity of vegetarianism grew during the 20th century as a result of nutritional, ethical, and—more recently—environmental and economic concerns. Virchand Gandhi was the official delegate representing Jainism at the first World's Parliament of Religions in Chicago in 1893. He was one of the first historical figures to defend Jain vegetarianism on a global stage to a Western audience. Gandhi systematically dismantled the contemporary Western assumption that vegetarianism led to physical weakness, successfully reframing the Jain diet in the West as a highly rational, scientifically grounded, and compassionate lifestyle.
States choose to balance for two reasons. First, they place their survival at risk if they fail to curb a potential hegemon before it becomes too strong; to ally with the dominant power means placing one's trust in its continued benevolence. Secondly, joining the weaker side increases the likelihood that the new member will be influential within the alliance. States choose to bandwagon because it may be a form of appeasement as the bandwagoner may hope to avoid an attack by diverting it elsewhere—a defensive reason—or because it may align with the dominant side in wartime to share the spoils of victory—an offensive reason. Realists claim that balancing is when states ally against the prevailing threat and results in a more secure world whereas in a bandwagoning world security is scarce as rising hegemons are not kept in check. With bandwagoning, the threatened state abandons hope of preventing the aggressor from gaining power at its expense and instead joins forces with its dangerous foe to get at least some small portion of the spoils of war. The weaker the state the more likely it is to bandwagon than to balance as they do little to affect the outcome and thus must choose the winning side. Strong states may change a losing side into a winning side and thus are more likely to balance. States will be tempted to bandwagon when allies are unavailable, however excessive confidence in allied support encourages weak states to free ride relying on the efforts of others to provide security.
=== Available forms === Mephedrone can come in capsules, tablets, or white powder, which users may swallow, insufflate, inject, smoke, or use rectally. When taken orally, users reported they could feel the effects within 15–45 minutes; when snorted, the effects were felt within minutes and peaked within half an hour. The effects last for between two and three hours when taken orally or nasally, but only half an hour if taken intravenously. It is sometimes sold mixed with methylone in a product called bubbles in the UK and also mixed with other cathinones, including ethcathinone, butylone, fluoromethcathinone and methedrone.
Sources: en.wikipedia.org
== Occurrence == Protactinium is one of the rarest and most expensive naturally occurring elements. It is found in the form of two isotopes, 231Pa and 234Pa, with the isotope 234Pa occurring in two different energy states. Nearly all natural protactinium is 231Pa. It is an alpha emitter and is formed by the decay of uranium-235, whereas the beta-radiating 234Pa is produced as a result of uranium-238 decay. Nearly all uranium-238 (99.8%) decays first to the shorter-lived 234mPa isomer. Protactinium occurs in uraninite (pitchblende) at concentrations of about 0.3–3 parts 231Pa per million parts (ppm) of ore. Whereas the usual content is closer to 0.3 ppm (e.g. in Jáchymov, Czech Republic), some ores from the Democratic Republic of the Congo have about 3 ppm. Protactinium is homogeneously dispersed in most natural materials and in water, but at much lower concentrations on the order of one part per trillion, corresponding to a radioactivity of 0.1 picocuries (pCi)/g. There is about 500 times more protactinium in sandy soil particles than in water, even when compared to water present in the same sample of soil. Much higher ratios of 2,000 and above are measured in loam soils and clays, such as bentonite.
== Function == Lactoferrin belongs to the innate immune system. Apart from its main biological function, namely binding and transport of iron ions, lactoferrin also has antibacterial, antiviral, antiparasitic, catalytic, anti-cancer, and anti-allergic functions and properties.
== Tissue distribution == EAAT1 is expressed throughout the CNS, and is highly expressed in astrocytes and Bergmann glia in the cerebellum. In the retina, EAAT1 is expressed in Muller cells. EAAT1 is also expressed in a number of other tissues including cardiac myocytes.
EDTA can also be used to test for bioavailability of heavy metals in sediments. However, it may influence the bioavailability of metals in solution, which may pose concerns regarding its effects in the environment, especially given its widespread uses and applications.
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。
It is normally kept frozen, desiccated, and away from light, with brief warming to room temperature before opening to limit condensation. Repeated freeze-thaw cycles are avoided because they stress the peptide. Once in solution, the material is held cold and used promptly.