The short version of 双受体激动 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-14. Anything still debated is marked as such rather than presented as settled.
Common degradation routes include hydrolysis of labile amide bonds, deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation. Aggregates can form during freeze-thaw cycling, at elevated pH, or when peptide concentration is high. Each route produces characteristic chromatographic or mass shifts that are tracked during stability studies. Whether a given minor impurity alters biological activity is often an open question, and specification limits are typically set on identity and purity rather than on functional data for trace species.
Lyophilized material is generally held at -20 degrees Celsius or lower, desiccated and protected from light, where it remains stable for extended periods. Reconstituted or ready-to-use solution is usually kept at 2 to 8 degrees Celsius with minimal agitation. Repeated freeze-thaw cycles should be avoided because they promote aggregation and reduce the soluble monomer fraction. Shipment of frozen solid commonly uses dry ice, while refrigerated liquid moves with validated cold packs. Stability beyond documented periods is not established.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid form |
| Purity assay | 95 percent or greater by RP-HPLC | Typical research-grade specification |
| Storage temperature | 2 to 8 degrees Celsius | Formulated solution, do not freeze |
| Common analytical method | LC-MS with peptide mapping | Identity and impurity confirmation |
| Primary degradation routes | Deamidation, oxidation, aggregation | Tracked in stability programs |
Like most synthetic peptides of this size, the material is commonly supplied as a lyophilised powder that appears white to off-white. It dissolves in aqueous buffers and in mixtures of water with a small proportion of organic solvent, though the fatty acid portion reduces solubility in pure water relative to short peptides. Hygroscopic behaviour is reported for many peptide powders, so weighing is usually performed quickly and under controlled humidity. Working solutions are typically prepared fresh and kept cold.
Long-term storage of lyophilised peptide powder is generally at minus twenty degrees Celsius or colder, with desiccant and protection from light. Short-term storage at two to eight degrees Celsius is common during active use. In solution, stability depends strongly on pH, concentration, and the presence of preservatives, and hydrolysis or aggregation can develop over weeks. Published stability data specific to this molecule are limited, so recommended conditions for research material are usually extrapolated from general peptide handling practice rather than from a dedicated study.
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.
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.
At the receptor level, tirzepatide activates both the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Both belong to the class B family of G protein-coupled receptors and signal largely through cyclic AMP accumulation. The compound binds the two receptors with differing affinity, and the pattern of signaling at each site is described in the literature as biased rather than simply proportional to occupancy. Tissues carrying these receptors include pancreatic islets, adipose tissue, the central nervous system, and the gastrointestinal tract. The relative weight of each receptor population in producing metabolic effects continues to be studied.
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.
=== Emulsifier === Only a limited number of emulsifiers are commonly regarded as safe to use for parenteral administration, of which the most important is lecithin. Lecithin can be biodegraded and metabolized, since it is an integral part of biological membranes, making it virtually non-toxic. Other emulsifiers can only be excreted via the kidneys, creating a toxic load. The emulsifier of choice for most fat emulsions used for parenteral nutrition is a highly purified egg lecithin, due to its low toxicity and complete integration with cell membranes. Use of egg-derived emulsifiers is not recommended for people with an egg allergy due to the risk of reaction. In situations where there is no suitable emulsifying agent for a person at risk of developing essential fatty acid deficiency, cooking oils may be spread upon large portions of available skin for supplementation by transdermal absorption. Another type of fat emulsion Omegaven is being used experimentally within the US primarily in the pediatric population. It is made of fish oil instead of the soybean oil based formulas more widely in use. Research has shown use of Omegaven may reverse and prevent liver disease and cholestasis.
=== Knockout studies === The large number of mouse compared to human FPR receptors makes it difficult to extrapolate human FPR functions based on genetic (e.g. gene knockout or forced overexpression) or other experimental manipulations of the FPR receptors in mice. In any event, combined disruption of the Fpr2 and Fpr3 genes causes mice to mount enhanced acute inflammatory responses as evidenced in three models, intestine inflammation caused by mesenteric artery ischemia-reperfusion, paw swelling caused by carrageenan injection, and arthritis caused by the intraperitoneal injection of arthritis-inducing serum. Since Fpr2 gene knockout mice exhibit a faulty innate immune response to intravenous listeria monocytogenes injection, these results suggest that the human FPR2 receptor and mouse Fpr3 receptor have equivalent functions in dampening at least certain inflammatory response.
The term "percent homology" is often used to mean "sequence similarity", that is the percentage of identical residues (percent identity), or the percentage of residues conserved with similar physicochemical properties (percent similarity), e.g. leucine and isoleucine, is usually used to "quantify the homology." Based on the definition of homology specified above this terminology is incorrect since sequence similarity is the observation, homology is the conclusion. The term "percent homology" is a misnomer; sequences are either homologous or not. As with morphological and anatomical structures, sequence similarity might occur because of convergent evolution, or, as with shorter sequences, by chance, meaning that they are not homologous. Homologous sequence regions are also called conserved. This is not to be confused with conservation in amino acid sequences, where the amino acid at a specific position has been substituted with a different one that has functionally equivalent physicochemical properties. Partial homology can occur where a segment of the compared sequences has a shared origin, while the rest does not. Such partial homology may result from a gene fusion event.
To determine if GSR is present in an area, presumptive tests, such as the modified Griess test and the sodium rhodizonate test, are performed. Any presumptive GSR samples are collected for confirmatory testing using instruments such as Scanning electron microscopy dispersive X-ray spectrometry (SEM-EDX) Flame or Graphite Furnace Atomic Absorption Spectrometry. There are both inorganic and organic components in GSR. Organic GSR (OGSR) consists of organic compounds such as nitroglycerine. Organic compounds can originate from the primer, propellants, lubricants or other additives used by manufacturers. Analysis of OGSR is not done with the same instrumentation as stated above, instead techniques like Gas Chromatography-Mass Spectrometry are used.
=== Diet === For most horses, diet has a significant impact on the degree of clinical signs. PSSM horses fed diets high in nonstructural carbohydrates (NSC), which stimulate insulin secretion, have been shown to have increased severity of rhabdomyolysis with exercise. Current recommendations for horses with PSSM include a low-starch, high-fat diet. Low-starch diets produce low blood glucose and insulin levels after eating, which may reduce the amount of glucose taken up by the muscle cells. High fat diets increase free fatty acid concentrations in the blood, which may promote the use of fat for energy (via free fatty acid oxidation) over glucose metabolism. Horses with the most severe clinical signs often show the greatest improvement on the diet. Dietary recommendations usually include a combination of calorie restriction, reduction of daily NSC content, and an increase in dietary fat. Diet recommendations need to be balanced with the animal's body condition score and exercise level, as it may be beneficial to wait on increasing dietary fat after an obese animal has lost weight. The diet should have <10% of digestible energy coming from NSC, and 15–20% of daily digestible energy coming from fat.
Sources: en.wikipedia.org
To make new legislation, TFEU article 294 defines the "ordinary legislative procedure" that applies for most EU acts. The essence is there are three readings, starting with a Commission proposal, where the Parliament must vote by a majority of all MEPs (not just those present) to block or suggest changes, and the Council must vote by qualified majority to approve changes, but by unanimity to block Commission amendment. Where the different institutions cannot agree at any stage, a "Conciliation Committee" is convened, representing MEPs, ministers and the commission to try to get agreement on a joint text: if this works, it will be sent back to the Parliament and Council to approve by absolute and qualified majority. This means, legislation can be blocked by a majority in Parliament, a minority in the council, and a majority in the commission: it is harder to change EU law than for it to stay the same. A different procedure exists for budgets. For "enhanced cooperation" among a sub-set of at least member states, authorisation must be given by the council. Member state governments should be informed by the Commission at the outset before any proposals start the legislative procedure. The EU as a whole can only act within its power set out in the Treaties. TEU articles 4 and 5 state that powers remain with the member states unless they have been conferred, although there is a debate about the Kompetenz-Kompetenz question: who ultimately has the "competence" to define the EU's "competence".
Supplementation of all B vitamins, such as B5 and B9, because they might alleviate some of the symptoms (such as arrhythmia). Levothyroxine for Hypothyroidism Supportive treatment for developmental delays Antiseizure medication
The colors of the paintings in the cella, although more intense, are still limited to browns, greens and oranges. The big eyes and wide eyelids remind of late Kushana works. These new types of paintings suggest the emergence of a bold new style in Kucha around that time. A painter, holding a cup of paint, and whose clothes "exactly match" the painters in the "Cave of the Painters" (caftan, boots...) is visible in one of the murals of the cave. Originally at the front end of the left corridor, behind the first statue, the painting is now located in the Hermitage Museum. Two more devotee figures with the same clothes were located in the back corridor as well. One of the statues is a man in a particular type of armour with sectioned areas, which used to stand as a protector (possibly a Vajrapani) to the left side of the colossal Buddha of the main cella. This type of armour was in use for several centuries in art of the Northern segment of the Silk Road, and later became prevalent in China. The head is a tentative addition. Lü Guang, a Chinese general sent by Emperor Fu Jian (r. 357–385) of the Former Qin dynasty (351–394), who temporarily conquered Kucha in 383–385 CE, mentioned the powerful armour of Kuchaen soldiers, a type of chainmail and lamellar armour of Sasanian inspiration which can also be seen in the paintings of the Kizil Caves:
There are many applications for AMS throughout a variety of disciplines. AMS is most often employed to determine the concentration of 14C, e.g. by archaeologists for radiocarbon dating. Compared to other radiocarbon dating methods, AMS requires smaller sample sizes (about 50 mg), while yielding extensive chronologies. MS technology has expanded the scope of radiocarbon dating. Samples ranging from 50,000 years old to 100 years old can be successfully dated using AMS, as other forms of mass spectrometry provide insufficient suppression of molecular isobars to resolve 13CH and 12CH2 from 14C atoms. Because of the long half-life of 14C, decay counting requires significantly larger samples. 10Be, 26Al, and 36Cl are used for surface exposure dating in geology. 3H, 14C, 36Cl, and 129I are used as hydrological tracers. Accelerator mass spectrometry is widely used in biomedical research. In particular, 41Ca has been used to measure bone resorption in postmenopausal women. List of accelerator mass spectrometry facilities Arizona Accelerator Mass Spectrometry Laboratory
Sources: en.wikipedia.org
The synthesis of adrenocortical steroid hormones involves a chain of oxidation-reduction reactions catalyzed by a series of enzymes. Synthesis begins with a molecule of cholesterol. Through shared intermediates and pathways branching off those shared intermediates, the different classes of steroids are synthesized. Steroids are synthesized from cholesterol in their respective regions of the adrenal cortex. The process is controlled by steroidogenic acute regulatory protein (StAR) which sits in the mitochondrial membrane and regulates the passage of cholesterol. This is the rate-limiting step of steroid biosynthesis. Once StAR has transported cholesterol into the mitochondria, the cholesterol molecule undergoes a string of oxidation-reduction reactions catalyzed by a series of enzymes from the family of cytochrome P450 enzymes. A coenzyme system called adrenodoxin reductase transfers electrons to the P450 enzyme which initiates the oxidation-reduction reactions that transform cholesterol into the steroid hormones. Though synthesis is initiated inside mitochondria, precursors are shuttled to the endoplasmic reticulum for processing by enzymes present in the endoplasmic reticulum. The precursors are shuttled back to the mitochondria in the region of the adrenal cortex within which synthesis initially began and it is there that synthesis is completed.
miR-324-5p likely regulates cell growth and survival through interaction with multiple pathways. Published research demonstrates that this miRNA interacts with the Hedgehog (HH) signaling pathway via interactions with HH transcription factor Gli1 and HH protein receptor Smo, often contributing to tumorigenesis. miR-324-5p's activating interaction with the protein NfkB also regulates numerous components of cell survival, including cell cycle control, enzyme synthesis, and cell adhesion. In addition, miR-324-5p regulates components of the MAPK pathway, influencing cell growth, proliferation, and survival. Specifically, miR-324-5p downregulates RAF and ERK and is necessary for normal levels of cell growth. Reduced expression leads to increased cell growth and proliferation, and overexpression limits growth, leading to its role in oncogenesis.
However, he can't open the hatch by himself. The player must fight through the asylum and the local theater, which is now overrun with zombified soldiers, to meet him on the other side. The player and the deputy take off in a police helicopter. The game reaches its climax as the player and the deputy are forced to fight Dr. Franklin, who, after taking the full impact of the blast in episode 2, has been rebuilt into a half-zombie, half-machine cyborg. After the doctor's defeat, the player is pursued by Sheriff Rockwood in another helicopter with a mounted mini-gun. The player must defeat the sheriff and send him plummeting toward one of the great lakes before exploding. The game ends with the player and the deputy flying off into the sunrise while the game plays "You Are What I Eat" along with the end credits.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is the standard approach, separating the main peak from related impurities. Ultraviolet detection near 214 nanometers captures the peptide backbone. Mass spectrometry is then used alongside chromatography to confirm identity and detect covalent modifications.
Cycling between frozen and liquid states concentrates the peptide at ice interfaces, which favors non-covalent association. The resulting aggregates may be invisible to simple assays yet alter recovery and apparent potency. Limiting the number of cycles and aliquoting before storage are common mitigations.
Tryptophan and methionine side chains can undergo photo-induced oxidation, so amber glass or opaque packaging is typical. The effect is gradual and depends on wavelength and exposure time. Light protection is usually specified for both solid and solution forms.
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。