This is a working overview of 双受体激动, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
Characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity and related-substance profiling, with ultraviolet detection near 214 nanometers. Mass spectrometry confirms molecular mass and reveals modifications such as oxidation or deamidation. Peptide mapping after enzymatic digestion verifies the amino acid sequence, while amino acid analysis supplies compositional data. Circular dichroism and infrared spectroscopy are used to assess secondary structure, particularly the alpha-helical content that influences aggregation behavior in solution.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized or solid form |
| Solubility | Sparingly soluble in water | May require buffer or pH adjustment |
| Typical storage temperature | 2–8 °C | Refrigerated; protect from light |
| Common analytical method | RP-HPLC | For purity and impurity profiling |
| Molecular weight | Approximately 4813 Da | For the peptide backbone; varies with counterions |
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。
Bulk peptide material is normally characterised by reversed-phase high-performance liquid chromatography, which separates the target sequence from truncation products and other closely related impurities. Ultraviolet detection near 214 nanometres is common because the peptide backbone absorbs in that region. Mass spectrometry, usually electrospray ionisation coupled to a mass analyser, is used to confirm the molecular mass. Because the molecule carries a lipophilic side chain, gradient methods often need a relatively high organic modifier fraction to elute it within a practical retention window.
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.
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.
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.
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.
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.
Interferon enhances the immune response by increasing the expression of genes involved in the antiviral immune response through activation of interferon receptors on the surface of the cell. Potential novel treatments including the NMT inhibitor, has been shown to completely inhibit Lassa (LAS) and Junín (JUN)viral infections in cells based assays. Another host-directed antiviral acts on EPRS1 which in turn acts, in human cells, as a proviral factor in mammarenaviruses infection, including LCMV, JUNV, and LASV, and its inhibition using halofuginon compound, a prolyl domain inhibitor of EPRS1, completely abolishes the viral infection by interrupting viral assembly and budding. PKR has been shown to act as a proviral factor while the inhibition of its kinase activity restricted the virus replication and infectivity.
==== Effectors ==== Pseudomonas syringae isolates carry a range of virulence factors called type III secretion system (T3SS) effector proteins. These proteins primarily function to cause disease symptoms and manipulate the host's immune response to facilitate infection. The major family of T3SS effectors in P. syringae is the hrp gene cluster, coding for the Hrp secretion apparatus.
=== 2024–present: I'm a Celebrity... South Africa and Everything. All At Once === In April 2024, Collins made a guest appearance on the E4 reality series The Underdog: Josh Must Win, in which contestants believe they are competing on a reality show called The Favourite, however unbeknownst to them, the game is being controlled by Amber Gill, Nick Grimshaw, Pete Wicks and Vicky Pattison who must ensure that Josh, a non-typical reality show contestant, is declared the winner. Collins was enlisted to help with a photoshoot in which she assigned costumes to the contestants and advised them on various different poses. In May 2024, Collins appeared on the Daily Mail's podcast series Everything I Know About Me where she spoke about her life and career. In September 2024, Collins appeared on the BBC genealogy documentary series Who Do You Think You Are?. Collins was keen to learn more about her mother's side of the family, after she was fostered at birth and ultimately discovered that her grandmother was a diagnosed chronic schizophrenic who spent time in two psychiatric hospitals. Throughout the episode, she meets her distant cousins who reside in Dagenham near to where Collins grew up, and sees a photo of her grandmother for the first time. She also discovers that her ancestors lived on Dorset Street in Spitalfields, where Jack the Ripper is believed to have murdered his final victim Mary Jane Kelly in November 1888. In January 2025, she appeared on an episode of Pointless Celebrities alongside Hayley Hasselhoff, filmed two years prior.
An overdose of benzodiazepines can cause dangerous deep unconsciousness, but are less toxic than their predecessors, the barbiturates, and death rarely results when a benzodiazepine is the only drug taken. Combined with other central nervous system (CNS) depressants such as alcohol and opioids, the potential for toxicity and fatal overdose increases significantly. Flumazenil is generally considered a first-line treatment in benzodiazepine overdose, although its usage outside the controllable environment of medical facilities possesses great risk of developing seizures and other life-threating conditions. Benzodiazepines are commonly used recreationally and also often taken in combination with other addictive substances, and are controlled in most countries.
== Clinical trials == Tedizolid proved its noninferiority to linezolid in two phase-III trials, known as the ESTABLISH trials. Tedizolid is the second treatment approved by the US Food and Drug Administration (FDA) under the Generating Antibiotic Incentives Now (known as the GAIN Act) federal law. New antibiotics manufactured under the act will be designated as a Qualified Infectious Disease Product (QIDP), allowing an expedited review by the FDA and an additional five years of market exclusivity.
Sources: en.wikipedia.org
=== Molecular representations for chirality === Computational methods for representing molecular chirality must encode three-dimensional stereochemical information in a format suitable for machine learning algorithms. SMILES (Simplified Molecular Input Line Entry System) notation incorporates stereochemistry through the use of @ and @@ symbols at chiral centers, where @ typically denotes anticlockwise and @@ denotes clockwise configuration when viewing the chiral center along the bond from the center to the first atom in the SMILES string. Traditional molecular descriptors used in computational chemistry, such as circular fingerprints (Extended Connectivity Fingerprints or ECFP), can encode structural information including stereochemical features. These descriptors represent molecules as fixed-length binary vectors that capture local atomic environments and connectivity patterns. However, conventional fingerprints may not optimally capture the subtle three-dimensional differences between enantiomers. Neural network-based molecular representations can be derived from SMILES strings. Variational autoencoders and heteroencoders trained on large databases of molecular structures can generate latent space vectors (LSVs) that encode molecular properties in a continuous, lower-dimensional space. These methods calculate difference vectors between the descriptor of a molecule and that of its enantiomer, or between the original descriptor and one derived from a stereochemistry-depleted SMILES string.
On multiple occasions the combined UNITA and SADF forces launched unsuccessful offensives which became bogged down in minefields along narrow avenues of approach and were abandoned when the attackers came under heavy fire from the Cuban and FAPLA artillerymen west of the Cuito River. The defenders' artillery was sited just beyond the maximum range of the South African artillery and on high ground which gave them a commanding view of the battlefield. This advantage, coupled with the proliferation of minefields, and heavily reinforced FAPLA-Cuban defensive positions rendered further attacks by the South African troops futile. Operations Hooper and Packer were terminated after the SADF had killed almost 700 FAPLA troops and destroyed about half of the Angolan brigades' remaining tanks and armoured vehicles. Cuba had suffered 42 dead and the loss of 6 tanks. South African casualties were relatively light: 13 dead and several dozen severely wounded. Three SADF tanks were also abandoned in a minefield, while most of the others were damaged beyond immediate repair or rendered unserviceable due to mechanical problems. UNITA suffered thousands of casualties, prompting accusations that its troops had been used as "cannon fodder" by the SADF. Cuban post-action reports claimed that UNITA insurgents had been sent through the minefields at gunpoint to clear the way for the South African armour.
===== Evidences against the happiness set point theory ===== In recent large panel studies divorce, death of a spouse, unemployment, disability and similar events have been shown to change the long-term subjective well-being, even though some adaptation does occur and inborn factors affect this. Fujita and Diener found that 24% of people changed significantly between the first five years of the study and the last five years. Almost one in four people showed changes in their well-being over the years; indeed sometimes those changes were quite dramatic. Bruce Headey found that 5–6% of people dramatically increased their life satisfaction over a 15- to 20-year period and that the goals people pursued significantly affected their life satisfaction.
Epitheliomuscular cells whose bodies form part of the epithelium but whose bases extend to form muscle fibers in parallel rows. The fibers of the outward-facing cell layer generally run at right angles to the fibers of the inward-facing one. In Anthozoa (anemones, corals, etc.) and Scyphozoa (jellyfish), the mesoglea also contains some muscle cells. Cnidocytes, the harpoon-like "nettle cells" that give the phylum Cnidaria its name. These appear between or sometimes on top of the muscle cells. Nerve cells. Sensory cells appear between or sometimes on top of the muscle cells, and communicate via synapses (gaps across which chemical signals flow) with motor nerve cells, which lie mostly between the bases of the muscle cells. Some form a simple nerve net. Interstitial cells, which are unspecialized and can replace lost or damaged cells by transforming into the appropriate types. These are found between the bases of muscle cells. In addition to epitheliomuscular, nerve and interstitial cells, the inward-facing gastroderm ("stomach skin") contains gland cells that secrete digestive enzymes. In some species it also contains low concentrations of cnidocytes, which are used to subdue prey that is still struggling. The mesoglea contains small numbers of amoeba-like cells, and muscle cells in some species. However, the number of middle-layer cells and types are much lower than in sponges.
Sources: en.wikipedia.org
In gastric tissue, a loss of parietal cells due to chronic inflammation has been shown to affect chief cell differentiation and can induce chief cells to transdifferentiate back into neck cells and can lead to the formation of mucus cell metaplasia known as spasmolytic polypeptide expressing metaplasia (SPEM) that could be precancerous. If parietal cells are lost, mature chief cells do not form. Parietal cells may secrete factors that lead to transdifferentiation of chief cells, so if lost, chief cells do not normally develop.
In memory of this event, every November 5 is observed as a special non-working holiday in the province through Republic Act No. 6709, signed by President Corazon Aquino on February 10, 1989. On November 27, 1898, the Cantonal Republic of Negros unilaterally proclaimed independence, but this was short-lived as the territory became a protectorate of the United States on April 30, 1899. The state was renamed the Republic of Negros (Spanish: República de Negros) on July 22, 1899, and eventually dissolved by the United States and annexed by the U.S. Military Government of the Philippine Islands on April 30, 1901. The leaders of the short-lived republic were:
In some cases, hepatocyte degeneration is uncommon. E.g., with Alagille syndrome limited degeneration occurs, however, there may be a small amount of apoptosis and enlarged hepatocytes. Cholestasis is often marked by cholate stasis, which are a set of changes that occur in the periportal hepatocytes. Cholate stasis is more common in obstructive cholestasis compared to non-obstructive cholestasis. During the cholate stasis process, hepatocytes first undergo swelling and then degeneration. Under the microscope, this is evident as a lucent cell periphery and enlarged cytoplasm around the nucleus. Oftentimes, Mallory bodies may also be found in the periportal areas. Due to the retention of bile, which contains copper, stains made for staining copper-associated protein can be used to visualize bile accumulation in the hepatocytes. Cholestatic liver cell rosettes may occur in children with chronic cholestasis. Histologically, this is evident as two or more hepatocytes in a pseudotubular fashion that encircle a segment of enlarged bile canaliculi. Children may also have giant hepatocytes present, which are characterized by a pigmented spongy appearance. Giant cell formation is likely caused by the detergent properties of bile salts causing a loss of the lateral membrane and joining of hepatocytes. In the case of Alagille syndrome, hepatocyte degeneration is uncommon. However, there may be a small amount of apoptosis and enlarged hepatocytes. In non-obstructive cholestasis, changes to the portal tracts are unlikely. However, it may occur in some unique situations.
Sources: en.wikipedia.org
RP-HPLC is widely used for purity and impurity profiling. Mass spectrometry confirms identity.
Typically refrigerated at 2–8 °C. Protect from light and avoid freezing.
Deamidation, oxidation, and aggregation products. SEC and ion-exchange chromatography are used.
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.