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 2026-03-22 and is reviewed periodically as new material appears.
Published work supports the view that engaging two incretin receptors produces changes in glucose handling and body weight larger than those seen with single-receptor activation. Why that difference arises is not fully settled. Open questions include how much of the observed weight effect depends on central versus peripheral signaling, and whether the two receptors form interacting complexes. Most reported findings come from controlled trials and animal models, and translation between species is imperfect. Further research is expected to refine these points over time.
Tirzepatide is a synthetic peptide built from 39 amino acid residues. Its sequence is related to human glucose-dependent insulinotropic polypeptide, with modifications that include a C-terminal extension and a C20 fatty diacid joined through a linker. Those changes raise the molecule's affinity for serum albumin, which slows renal filtration and lengthens the time it stays in circulation. The free base has an average molecular mass near 4813.5 daltons. The compound is made by solid-phase peptide synthesis followed by chromatographic purification.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C225H348N48O68 | 39-residue synthetic peptide |
| Average molecular mass | About 4813.5 Da | Free base form |
| Appearance | White to off-white powder | Solid after lyophilization |
| Solubility class | Freely soluble in water | Also soluble in neutral aqueous buffers |
| Typical storage | At or below -20 °C, desiccated | Protect from light and moisture |
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。
固体状态的 tirzepatide 通常以冻干粉形式保存，推荐在低温、避光、干燥条件下存放，常见区间为 2 至 8 摄氏度，长期保存可考虑更低温度并避免反复冻融。冻融循环会导致肽链聚集或析出，从而影响后续定量结果。容器密封性与湿度控制同样是稳定性研究中反复强调的因素。
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。
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.
The Parliament of Canada passes all federal statute laws. It comprises the monarch, the House of Commons, and the Senate. While Canada inherited the British concept of parliamentary supremacy, this was later, with the enactment of the Constitution Act, 1982, all but completely superseded by the American notion of the supremacy of the law. Each of the 343 members of Parliament in the House of Commons is elected by simple plurality in an electoral district or riding. The Constitution Act, 1982, requires that no more than five years pass between elections, although the Canada Elections Act limits this to four years with a "fixed" election date in October; general elections still must be called by the governor general and can be triggered by either the advice of the prime minister or a lost confidence vote in the House. The 105 members of the Senate, whose seats are apportioned on a regional basis, serve until age 75. Canadian federalism divides government responsibilities between the federal government and the 10 provinces. Provincial legislatures are unicameral and operate in parliamentary fashion similar to the House of Commons. Canada's three territories also have legislatures, but these are not sovereign, have fewer constitutional responsibilities than the provinces, and differ structurally from their provincial counterparts.
=== Rules for generic biologics === Since the 1990s, many successful new drugs for the treatment of cancer, autoimmune diseases, and other conditions have been protein-based biotechnology drugs, regulated by the Center for Biologics Evaluation and Research. Many of these drugs are extremely expensive; for example, the anti-cancer drug Avastin costs $55,000 for a year of treatment, while the enzyme replacement therapy drug Cerezyme costs $200,000 per year, and must be taken by Gaucher's disease patients for life. Biotechnology drugs do not have the simple, readily verifiable chemical structures of conventional drugs, and are produced through complex, often proprietary, techniques, such as transgenic mammalian cell cultures. Because of these complexities, the 1984 Hatch-Waxman Act did not include biologics in the Abbreviated New Drug Application (ANDA) process. This precluded the possibility of generic drug competition for biotechnology drugs. In February 2007, identical bills were introduced into the House to create an ANDA process for the approval of generic biologics, but were not passed.
A mass spectrum is a histogram plot of intensity vs. mass-to-charge ratio (m/z) in a chemical sample, usually acquired using an instrument called a mass spectrometer. Not all mass spectra of a given substance are the same; for example, some mass spectrometers break the analyte molecules into fragments; others observe the intact molecular masses with little fragmentation. A mass spectrum can represent many different types of information based on the type of mass spectrometer and the specific experiment applied. Common fragmentation processes for organic molecules are the McLafferty rearrangement and alpha cleavage. Straight chain alkanes and alkyl groups produce a typical series of peaks: 29 (CH3CH2+), 43 (CH3CH2CH2+), 57 (CH3CH2CH2CH2+), 71 (CH3CH2CH2CH2CH2+) etc.
=== Pharmaceuticals === The expiration date of pharmaceuticals specifies the date the manufacturer guarantees the full potency and safety of a drug. Most medications continue to be effective and safe for a time after the expiration date. A rare exception is a case of renal tubular acidosis purportedly caused by expired tetracycline. A study conducted by the U.S. Food and Drug Administration covered over 100 drugs, prescription and over-the-counter. The study showed that about 90% of them were safe and effective as long as 15 years past their expiration dates. Joel Davis, a former FDA expiration-date compliance chief, said that with a handful of exceptions - notably nitroglycerin, insulin and some liquid antibiotics - most expired drugs are probably effective. Shelf life is not significantly studied during drug development, and drug manufacturers have economic and liability incentives to specify shorter shelf lives so that consumers are encouraged to discard and repurchase products. One major exception is the Shelf Life Extension Program (SLEP) of the U.S. Department of Defense (DoD), which commissioned a major study of drug efficacy from the FDA starting in the mid-1980s. One criticism is that the U.S. Food and Drug Administration (FDA) refused to issue guidelines based on SLEP research for normal marketing of pharmaceuticals even though the FDA performed the study. The SLEP and FDA signed a memorandum that scientific data could not be shared with the public, public health departments, other government agencies, and drug manufacturers.
Sources: en.wikipedia.org
Mexico: Viajero Confiable is a Mexican trusted traveller programme which allows members to pass securely through customs and immigration controls in reduced time, using automated kiosks at participating airports. Viajero Confiable was introduced in three airports in 2014 and has since expanded to additional sites. Like the NEXUS, Global Entry, and TSA PreCheck programs, Viajero Confiable members travelling through participating airports may use designated lanes to clear customs quickly and securely, as the Mexican government has already conducted a background check on them and they are considered trusted travellers. At the participating airports, members may use automated kiosks to scan their passport and fingerprints, and complete an electronic immigration form. The programme is targeted at Mexican citizens, as well as U.S. or Canadian citizens who are members of the Global Entry or NEXUS programme and are lawful permanent residents of Mexico. New Zealand: In New Zealand, a SmartGate system exists at Auckland, Wellington, Christchurch and Queenstown airports, enabling holders of biometric passports issued by New Zealand, Australia, Canada, China, France, Germany, Ireland, the Netherlands, the United Kingdom, and the United States to clear border controls using automated facilities. The system can currently only be used by travellers 12 years of age or older; however, a trial is underway that may lower the age of eligibility to use eGate for people with an eligible ePassport from 12 to 10 years of age.
Targeted drug delivery, sometimes called smart drug delivery, is a method of delivering medication to a patient in a manner that increases the concentration of the medication in some parts of the body relative to others. This means of delivery is largely founded on nanomedicine, which plans to employ nanoparticle-mediated drug delivery in order to combat the downfalls of conventional drug delivery. These nanoparticles would be loaded with drugs and targeted to specific parts of the body where there is solely diseased tissue, thereby avoiding interaction with healthy tissue. The goal of a targeted drug delivery system is to prolong, localize, target and have a protected drug interaction with the diseased tissue. The conventional drug delivery system is the absorption of the drug across a biological membrane, whereas the targeted release system releases the drug in a dosage form. The advantages to the targeted release system is the reduction in the frequency of the dosages taken by the patient, having a more uniform effect of the drug, reduction of drug side-effects, and reduced fluctuation in circulating drug levels. The disadvantage of the system is high cost, which makes productivity more difficult, and the reduced ability to adjust the dosages. Targeted drug delivery systems have been developed to optimize regenerative techniques. The system is based on a method that delivers a certain amount of a therapeutic agent for a prolonged period of time to a targeted diseased area within the body.
== Awards == Hunt has been awarded several honors including the Distinguished Contribution Award from the American Society for Mass Spectrometry in 1994; the Christian B. Anfinsen Award from the Protein Society; the Chemical Instrumentation Award and Field and Franklin Award from the American Chemical Society; the Thomson Medal from the International Mass Spectrometry Society; the Human Proteome Organization's Distinguished Achievement Award in Proteomics, and the Association of Biomolecular Resource Facilities 2007 Award. In addition, he also received the Charles H. Stone Award (American Chemical Society) and the Pehr Edman Award for outstanding achievements in the application of mass spectrometry. He received the Chemical Instrumentation Award sponsored by the American Chemical Society in 1997.
Sources: en.wikipedia.org
The NK-92 cell line is an immortalised cell line that has the characteristics of a type of immune cell found in human blood called 'natural killer' (NK) cells. Blood NK cells and NK-92 cells recognize and attack cancer cells as well as cells that have been infected with a virus, bacteria, or fungus. NK-92 cells were first isolated in 1992 in the laboratory of Hans Klingemann at the British Columbia Cancer Agency in Vancouver, Canada, from a patient who had a rare NK cell non-Hodgkin-lymphoma. These cells were subsequently developed into a continuously growing cell line. NK-92 cells are distinguished by their suitability for expansion to large numbers, ability to consistently kill cancer cells and testing in clinical trials. When NK-92 cells recognize a cancerous or infected cell, they secrete perforin that opens holes into the diseased cells and releases granzymes that kill the target cells. NK-92 cells are also capable of producing cytokines such as tumor necrosis factor alpha (TNF-a) and interferon gamma (IFN-y), which stimulates proliferation and activation of other immune cells.
This page discusses each of the main elements in the mixture of fission products produced by nuclear fission of the common nuclear fuels uranium and plutonium. The isotopes are listed by element, in order by atomic number. Neutron capture by the nuclear fuel in nuclear reactors and atomic bombs also produces actinides and transuranium elements (not listed here). These are found mixed with fission products in spent nuclear fuel and nuclear fallout. Neutron capture by materials of the nuclear reactor (shielding, cladding, etc.) or the environment (seawater, soil, etc.) produces activation products (not listed here). These are found in used nuclear reactors and nuclear fallout. A small but non-negligible proportion of fission events produces not two, but three fission products (not counting neutrons or subatomic particles). This ternary fission usually produces a very light nucleus such as helium (about 80% of ternary fissions produce an alpha particle) or hydrogen (most of the rest produce tritium or to a lesser extent deuterium and protium) as the third product. This is the main source of tritium from light water reactors. Another source of tritium is Helium-6 which immediately decays to (stable) Lithium-6. Lithium-6 produces tritium when hit by neutrons and is one of the main sources of commercially or militarily produced tritium. If the first or only step of nuclear reprocessing is an aqueous solution (as is the case in PUREX) this poses a problem as tritium contamination cannot be removed from water other than by costly isotope separation.
13 July Air pollution particles are shown to reduce insects' ability to find food and a mate, in experiments. This may be contributing to the dramatic fall in global insect populations, the scientists conclude. Scientists use CRISPR gene-editing to reduce the lignin content in poplar trees by as much as 50%, offering a potentially more sustainable method of fiber production. 14 July – The Indian Space Research Organisation (ISRO) successfully launches its Chandrayaan-3 spacecraft towards the Moon, aiming to become the fourth nation to achieve a soft landing on the lunar surface. 17 July – Astronomers of the Breakthrough Listen project report the development of a novel technique that can help distinguish between potential deliberate artificial alien signals and Earth-based radio interference via unique signatures from passing through ionized plasma of interstellar medium. 19 July – Astronomers report the discovery of a bizarre 'two-faced' star, with one side made up of hydrogen and the other consisting of helium. The object, designated ZTF J203349.8+322901.1, is a white dwarf located about 1,000 light years away. 18 July – The first example of naturally occurring graphene is reported, at a gold mine in South Africa. 19 July – Researchers report the discovery of self-healing of fatigue cracks in metals in vacuum.
Sources: en.wikipedia.org
It is a synthetic peptide and a dual agonist of two incretin receptors. It is not a small molecule, and it is not structurally related to the older single-receptor peptide agonists.
The C20 fatty diacid promotes tight binding to serum albumin. That binding reduces renal clearance and extends circulation time compared with an unmodified peptide of similar length.
It is not fully established. Studies indicate that both receptors contribute to the observed effects, but the exact split between the two signaling pathways in humans remains an open question.
Peptide mapping with tandem mass spectrometry is the standard approach. The peptide is digested with an enzyme such as trypsin, and the resulting fragments are matched against the expected sequence.