Everything below concerns 肠促胰素. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
In clinical research, tirzepatide has been studied in randomized controlled trials for glycemic control and body weight reduction. These trials typically measure changes in hemoglobin A1c and body weight over periods of several months. The drug is administered by subcutaneous injection, and its pharmacokinetic profile supports once-weekly dosing. Post-marketing surveillance continues to evaluate long-term outcomes and rare adverse events.
Tirzepatide is a synthetic peptide that acts as a dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. The molecule contains 39 amino acids and features a C20 fatty diacid moiety attached via a linker, which promotes albumin binding and extends its circulating half-life. Its sequence incorporates non-natural amino acids and modifications that reduce susceptibility to degradation by dipeptidyl peptidase-4. This dual receptor activity distinguishes it from selective GLP-1 receptor agonists.
The GIP receptor is expressed in pancreatic islets, adipose tissue, and the central nervous system, while GLP-1 receptors are found in pancreatic islets, the gastrointestinal tract, and the brain. Activation of both receptors can enhance glucose-dependent insulin secretion and reduce glucagon release. The relative contribution of each receptor to the overall pharmacological effect remains an area of ongoing investigation. Preclinical studies suggest that GIP receptor agonism may modulate appetite and energy balance, but the precise mechanisms in humans are not fully established.
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。
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 |
|---|---|---|
| Molecular class | Synthetic peptide | Dual GIP/GLP-1 receptor agonist |
| Amino acid count | 39 | Contains non-natural residues |
| Modification | C20 fatty diacid | Attached via linker; promotes albumin binding |
| Half-life | Approximately 5 days | Supports once-weekly dosing |
| Primary route | Subcutaneous injection | Not for intravenous use |
After subcutaneous injection, absorption is gradual, and peak plasma levels are generally reached within one to three days. Albumin binding extends the apparent half-life to roughly five days, which supports a weekly administration schedule. Metabolism proceeds mainly through proteolytic cleavage of the peptide backbone and beta-oxidation of the fatty acid chain, rather than through cytochrome P450 pathways. Eliminated fragments are largely recycled through general protein turnover, and excretion of intact drug in urine is minimal. These properties distinguish the molecule from short-acting incretin mimetics.
Tirzepatide is a synthetic peptide of 39 amino acids engineered from the native glucose-dependent insulinotropic polypeptide sequence. Its structure incorporates several non-natural residues and a C-terminal segment derived from glucagon-like peptide-1, together with a C20 fatty diacid moiety attached through a linker. The lipophilic side chain promotes binding to serum albumin, which slows renal clearance after administration. The compound is classified as a dual incretin receptor agonist and is supplied as a lyophilized powder for reconstitution or as a preformulated solution, depending on the presentation.
The peptide activates two G protein-coupled receptors, GIPR and GLP-1R. Binding triggers adenylyl cyclase activity and raises intracellular cyclic AMP in pancreatic beta cells, which potentiates insulin release when glucose is elevated. Signaling in the central nervous system is associated with reduced appetite and lower energy intake, while effects on gastric emptying and glucagon secretion are also reported. Because activity at both receptors is retained, the pharmacological profile is often described as incretin-based rather than selective for a single receptor.
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.
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.
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.
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.
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.
== Advertising == A&W does not do national advertising; the primary factor for such being the lack of restaurants in certain parts of the United States. Its first attempt at doing a national television commercial was on June 16, 1969, when it booked for a slot on NBC's Monday Night at the Movies to advertise take-home gallons of root beer. In 1976, A&W Restaurants participated in the Easter Seals Telethon, where money from large root beer mugs was collected by the local restaurant on behalf of the TV station broadcasting the telethon in the area. In 1997, the chain adopted All American Food as its slogan in order to achieve widespread brand recognition. The chain increased its marketing budget in February 2000, eyeing for a new line of burgers in January 2001. For the summer of 2007, the chain launched the Moove to American campaign, which was created to counter competing chains relying exclusively on foreign beef; the campaign started on June 28 with a stunt featuring 35 cows sent on a barge to the Statue of Liberty. The aim was to petition the National Cattlemen's Beef Association to support consumption of U.S. beef. There was also a campaign to set up a new custom burger, with the winner heading over to Louisville to work for its serving in restaurants. A grassroots partnership with Green Bay Packers receiver Greg Jennings began in 2009, where Papa Burgers were sold at a price of 85 cents in Green Bay restaurants if Jennings made a touchdown. Due to its success, the campaign expanded to include all of Wisconsin in 2010.
=== Trust in the institutions === In 2019, the Pew Research Center interviewed over 2,000 Americans aged 18 and over on their views of various components of the federal government. They found that 54% of the people between the ages of 18 and 29 wanted larger government compared to 43% who preferred smaller government and fewer services. Older people were more likely to pick the second option. 2018 polls conducted by the Pew Research Center found that 70% of Americans aged 13 to 17 wanted the government to play a more active role in solving their problems. A 2022 poll by Pew showed that overall, medical experts, the military, and scientists were among the most trusted groups in the United States. But while a majority of Americans believed it was important for their country to remain a global leader in science, people aged 18 to 29 were somewhat less inclined to think so compared to older cohorts and were slightly more optimistic about the standing of U.S. science on the international stage. However, Generation Z's trust in institutions or the nation itself has been declining. Polls conducted during the early 2020s showed that only a minority of Americans aged 18–29 thought that their country was heading in the right direction or agreed that democracy was the best form of government. About two thirds did not trust their government.
==== Rentosertib ==== Rentosertib is an investigational new drug that targets TNIK (TRAF2 and NCK-interacting protein kinase). It is asserted to be the first drug generated entirely by generative AI to reach mid-stage human clinical trials, and the first to target a novel AI-discovered biological pathway. A multicenter, double-blind, placebo-controlled, randomized phase 2a trial was conducted in China, testing the drug in 71 IPF patients from July 2023 to June 2024, encompassing an administration period of 12 weeks. Participants were randomly assigned to receive 30 mg once daily (QD), 30 mg twice daily (BID), 60 mg QD, or placebo. The trial's primary endpoint was the incidence of treatment-emergent adverse events (TEAEs).
=== Plants === In plants, ADH catalyses the same reaction as in yeast and bacteria to ensure that there is a constant supply of NAD+. Maize has two versions of ADH – ADH1 and ADH2, Arabidopsis thaliana contains only one ADH gene. The structure of Arabidopsis ADH is 47%-conserved, relative to ADH from horse liver. Structurally and functionally important residues, such as the seven residues that provide ligands for the catalytic and noncatalytic zinc atoms, however, are conserved, suggesting that the enzymes have a similar structure. ADH is constitutively expressed at low levels in the roots of young plants grown on agar. If the roots lack oxygen, the expression of ADH increases significantly. Its expression is also increased in response to dehydration, to low temperatures, and to abscisic acid, and it plays an important role in fruit ripening, seedlings development, and pollen development. Differences in the sequences of ADH in different species have been used to create phylogenies showing how closely related different species of plants are. It is an ideal gene to use due to its convenient size (2–3 kb in length with a ≈1000 nucleotide coding sequence) and low copy number.
=== Surface plasmon resonance === The SBP-Tag has been used to reversibly immobilize recombinant proteins onto streptavidin-functionalized surfaces thereby permitting interaction assessment such as by surface plasmon resonance (SPR) techniques with re-use of the functionalized surface. SPR has also been used to compare the SBP-Tag with other streptavidin-binding peptides such as Strep-tag.
Sources: en.wikipedia.org
=== Mutational convergence === The most well-studied example is the Spike protein of SARS-CoV-2, which independently evolved at the same positions regardless of the underlying sublineage. The most eminent examples from the pre-Omicron era were E484K and N501Y, while in the Omicron era examples include R493Q, R346X, N444X, L452X, N460X, F486X, and F490X.
== R == Ronald T. Raines (born 1958), American chemist Adam Vladislavovich Rakovsky (1879–1941), Soviet physical chemist Venkatraman Ramakrishnan (born 1952), 2009 Nobel Prize in Chemistry William Ramsay (1852–1916), Scottish chemist, 1904 Nobel Prize in Chemistry C. N. R. Rao (born 1934), Indian chemist François-Marie Raoult (1830–1901), French chemist, known for Raoult's law Henry Rapoport (1918–2002), American chemist, UC Berkeley William Sage Rapson (1912–1999), South African chemist and co-author of Gold Usage Nil Ratan Dhar (1892–1986), Pioneering Indian soil chemist Ken Raymond (born 1942), American inorganic and bioinorganic chemist, UC Berkeley Prafulla Chandra Ray (1861–1944), Indian chemist Julius Rebek (born 1944), Hungarian American chemist Charles Lee Reese (1862–1940), American chemist and Chemical Director of DuPont Henri Victor Regnault (1810–1878), French chemist and physicist Tadeus Reichstein (1897–1996), chemist, 1950 Nobel Prize in Physiology or Medicine Oleg Reutov (1920-1998), soviet organic chemist Rhazes (Razi) (865–925), Persian physician, philosopher and alchemist Stuart A.
In 1948, the Australian psychiatrist John Cade discovered the usefulness of lithium salts in treating mania while working at the Bundoora Repatriation Mental Hospital in Melbourne. He was injecting guinea pigs with urine extracts taken from manic patients in an attempt to isolate a metabolic compound which might be causing mental symptoms. Since uric acid in gout was known to be psychoactive, he needed soluble urate for a control. He used lithium urate, already known to be the most soluble urate compound, and observed that it caused the guinea pigs to become tranquil. Cade traced the effect to the lithium ion itself, and after Cade ingested lithium himself to ensure its safety in humans, he proposed lithium salts as tranquilizers. In 1949, he published his findings in the Medical Journal of Australia in a paper entitled "Lithium salts in the treatment of psychotic excitement". He soon succeeded in controlling mania in chronically hospitalized patients with lithium. This was one of the first successful applications of a drug to treat mental illness, and it opened the door for the development of medicines for other mental problems in the next decades. In 1950, one of Cade's first patients died of lithium toxicity after Cade had successfully treated him and released him from the hospital. Afterward, Cade abandoned the research of lithium and focused instead on testing other salts of rubidium, cerium, and strontium for their potential utility in psychiatry.
== Target == In research on Xenopus oocytes, it was found that kurtoxin affects low-threshold α1G and α1H calcium channels, but not the high-threshold α1A, α1B, α1C, and α1E Ca channels. Like other α-scorpion toxins, kurtoxin was also found to interact with voltage-gated sodium channels. In rat neurons, less selectivity for kurtoxin on calcium channels is found. Here, the toxin interacts with high affinity with T-type, L-type, N-type, and P-type channels.
isochore A large region of genomic DNA with a relatively homogeneous composition of base pairs, distinguished from other regions by the proportion of pairs that are G-C or A-T. The genomes of most plants and vertebrates are composed of different classes of GC-rich and AT-rich isochores.
Sources: en.wikipedia.org
It activates both GIP and GLP-1 receptors. This dual action differentiates it from selective GLP-1 agonists.
It is given as a subcutaneous injection. Its long half-life supports weekly dosing.
No, it is synthetic. It contains non-natural amino acids and a fatty acid modification.
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。