Everything below concerns 脂肪酸侧链. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
The peptide backbone contains 39 amino acids and includes alpha-aminoisobutyric acid residues, which are not among the standard proteinogenic set. A C20 fatty diacid moiety is attached through a linker, allowing the compound to bind serum albumin and extend its circulation time. This albumin binding is the main reason the molecule supports once-weekly administration rather than more frequent dosing. The measured molecular mass is approximately 4,813 daltons, placing it firmly in the peptide rather than small-molecule class.
Tirzepatide is a synthetic peptide that activates both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. This dual agonist profile distinguishes it from earlier incretin-based compounds that act on a single receptor. The molecule was engineered from the native GIP sequence and carries several non-natural residues that slow enzymatic breakdown. Researchers designed it to combine the insulinotropic effects of GIP signaling with the appetite and gastric-emptying effects associated with GLP-1 activation.
Pharmacologically, tirzepatide activates two distinct G protein-coupled receptors: the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Binding at each target triggers cyclic AMP accumulation and downstream signaling in pancreatic beta cells, adipose tissue and the central nervous system. Because the two pathways overlap only partially, the combined effect on insulin secretion, glucagon suppression and appetite signaling differs from that of selective single-receptor compounds. Affinity is not equal across the two targets, and the clinical meaning of that imbalance remains an area of active study.
Clinical research programs have evaluated tirzepatide in adults with type 2 diabetes and in adults with obesity or excess weight. Trials generally reported reductions in glycated hemoglobin and body weight across treatment periods of several months. Since these studies enrolled defined populations under controlled conditions, the findings describe group averages rather than individual outcomes. Open questions include the durability of effects after treatment stops, variation among subgroups, and the long-term consequences of sustained dual receptor stimulation. Published trial summaries should be consulted for exact measurements rather than secondary accounts.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Modified synthetic peptide | 39-residue backbone with non-natural residues |
| Receptor targets | GIP and GLP-1 | Dual incretin receptor agonist |
| Approximate molecular mass | 4,813 Da | Calculated from the peptide sequence |
| Administration route | Subcutaneous injection | Weekly schedule in approved products |
| Albumin binding | Present | Mediated by a C20 fatty diacid side chain |
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.
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。
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.
Tirzepatide is a synthetic peptide composed of 39 amino acids. It acts as a dual agonist at two incretin receptors, the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. The molecule was designed by modifying the native sequence of glucose-dependent insulinotropic polypeptide to improve metabolic stability and extend its circulation time. Its structure includes several non-natural amino acid residues and a fatty acid side chain. These features distinguish it from earlier single-receptor incretin analogs studied in the same period.
Tirzepatide is a synthetic linear peptide of 39 amino acids that acts as a dual agonist at the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. Its sequence derives from native GIP but incorporates non-natural residues and a C20 fatty diacid moiety linked to a lysine side chain. The lipophilic chain promotes albumin binding, which slows renal clearance and extends circulation time. The unmodified peptide has a molecular formula of C225H348N48O68 and a molecular mass near 4,813 daltons.
Receptor activation by tirzepatide raises intracellular cyclic AMP through Gs-coupled signalling at both targets. At the GLP-1 receptor the downstream effect includes glucose-dependent insulin release, suppressed glucagon secretion, delayed gastric emptying, and reduced appetite signalling in the hypothalamus. GIP receptor engagement adds insulinotropic activity and appears to influence lipid handling in adipose tissue. Because both receptors are stimulated at the same time, the pharmacological profile differs from that of selective GLP-1 receptor agonists, and the relative contribution of each arm remains an area of active investigation.
Stachys affinis, commonly called crosne, Chinese artichoke, Japanese artichoke, knotroot, or artichoke betony, is a perennial herbaceous plant of the family Lamiaceae, originating from China. Its rhizome is a root vegetable that can be eaten raw, pickled, dried or cooked.
== Causes == Refeeding syndrome – This causes a demand for phosphate in cells due to the action of hexokinase, an enzyme that attaches phosphate to glucose to begin metabolism of glucose. Also, production of ATP when cells are fed and recharge their energy supplies requires phosphate. A similar mechanism is seen in the treatment of diabetic ketoacidosis, which can be complicated by respiratory failure in these cases due to respiratory muscle weakness. Respiratory alkalosis – Any alkalemic condition moves phosphate out of the blood into cells. This includes most common respiratory alkalemia (a higher than normal blood pH from low carbon dioxide levels in the blood), which in turn is caused by any hyperventilation (such as may result from sepsis, fever, pain, anxiety, drug withdrawal, and many other causes). This phenomenon is seen because in respiratory alkalosis carbon dioxide (CO2) decreases in the extracellular space, causing intracellular CO2 to freely diffuse out of the cell. This drop in intracellular CO2 causes a rise in cellular pH which has a stimulating effect on glycolysis. Since the process of glycolysis requires phosphate (the end product is adenosine triphosphate), the result is a massive uptake of phosphate into metabolically active tissue (such as muscle) from the serum. However, that this effect is not seen in metabolic alkalosis, for in such cases the cause of the alkalosis is increased bicarbonate rather than decreased CO2. Bicarbonate, unlike CO2, has poor diffusion across the cellular membrane and therefore there is little change in intracellular pH.
The Copyright Term Directive 2006 article 1 states the principle that copyrights last for 70 years after the death of the author. The Copyright and Information Society Directive 2001 was passed to regulate copyright over the internet, and the effect of article 5 is that internet service providers are not liable for data they transmit even if it infringes copyright. However under article 6, member states must give "adequate legal protection" for copyrights. The Resale Rights Directive creates a right to royalties for authors where works are resold. The Enforcement Directive requires member states have effective remedies and legal processes. Under the European Patent Convention, which is separate from the EU, the general patent term is 20 years from the date that a patent (of an invention) is filed with an official register, and the development of an EU patent attempts to harmonise standards around these norms. The Trade Marks Directive enables a common system of trade mark registration so that, with exceptions, a registered trade mark applies across all EU member states.
== Theca interna == Theca interna cells express receptors for luteinizing hormone (LH) to produce androstenedione (an androgen), which via a few steps, gives the granulosa cells the precursor for estrogen manufacturing. After rupture of the mature ovarian follicle, the theca interna cells differentiate into the theca lutein cells of the corpus luteum, which continue to secrete androgens.
Sources: en.wikipedia.org
=== Straight side chain === The genetic code has been described as a frozen accident and the reasons why there is only one standard amino acid with a straight chain, alanine, could simply be redundancy with valine, leucine and isoleucine. However, straight chained amino acids are reported to form much more stable alpha helices.
On April 5, the Iraqi government announced "the complete crushing of acts of sedition, sabotage and rioting in all towns of Iraq." An estimated 25,000 to 100,000 Iraqis were killed in the uprisings. In Kuwait, the Emir was restored, and suspected Iraqi collaborators were repressed. Eventually, over 400,000 people were expelled from the country, including a large number of Palestinians, because of PLO support of Saddam. Yasser Arafat did not apologize for his support of Iraq, but after his death Mahmoud Abbas formally apologized in 2004 on behalf of the PLO. This came after the Kuwaiti government formally forgave the group. There was some criticism of the Bush administration, as they chose to allow Saddam to remain in power instead of pushing on to capture Baghdad and overthrowing his government. In their co-written 1998 book, A World Transformed, Bush and Brent Scowcroft argued that such a course would have fractured the alliance, and would have had many unnecessary political and human costs associated with it. In 1992, the US defense secretary during the war, Dick Cheney, made the same point:
=== Ch–Che === Michael Chamberlin (1937–2025). American molecular biologist at UC Berkeley, with research focussed on gene expression in both prokaryotes and eukaryotes. Member Natl. Acad. Sci. USA. Britton Chance (1913–2010). American biochemist at the University of Pennsylvania. He studied enzyme structure and function, and invented the stopped-flow spectrophotometer for studying fast reactions. Member Natl. Acad. Sci. USA. Christopher Chang (b. 1974). American bioinorganic chemist at UC Berkeley. His research includes molecular imaging sensors for the study of redox biology. Jean-Pierre Changeux (b. 1936). French biochemist and neuroscientist at the Collège de France and Institut Pasteur. Originator of the allosteric model of cooperativity, but now known mainly for work in neuroscience. Emmett Chappelle (1925–2019). American biochemist at NASA, known for using bioluminescence to develop a method of detecting ATP. Erwin Chargaff (1905–2002). Austrian-American biochemist at Columbia, known for Chargaff's rules, according to the first of which the number of guanine units in DNA is equal to the number of cytosine units, and the number of adenine units is equal to the number of thymine units. Emmanuelle Charpentier (b. 1968). French microbiologist, geneticist and biochemist. She (with Jennifer Doudna) discovered genome editing with CRISPR. Nobel Prize for Chemistry in 2020. Foreign Associate Natl. Acad. Sci. USA Martha Chase (1927–2003).
=== Mosquitoes === Methods of resistance include thickening of the cuticle of the insect to limit permeation of the insecticide, metabolic resistance via overexpression of metabolizing cytochrome P450 mono-oxygenases and glutathione-S-transferases, and the knockdown resistance (kdr) sodium channel mutations which render the action of insecticides ineffectual, even when co-administered with piperonyl butoxide. Characterization of the different forms of resistance among mosquitoes has become a top priority in groups studying tropical medicine due to the high mortality of those who reside in endemic areas.
Ammunition and other resources are generally placed in locations appropriate to the environment rather than appearing as arbitrary pickups; contemporary reviewers noted that weapons, ammunition, and health supplies were integrated into the surrounding world to reinforce the game's sense of realism. The game frequently combines combat with environmental puzzles. These challenges can involve operating machinery, navigating conveyor systems, manipulating movable objects, finding alternative routes, or using environmental hazards against enemies. For example, the player can manipulate valves to release dangerous steam, while boxes and other objects can be arranged to create paths to otherwise inaccessible areas. These puzzles are generally presented as problems within the environment rather than as explicitly marked challenges, requiring the player to observe the surroundings and determine an appropriate solution. Enemy encounters are similarly integrated into the environment. The player encounters a variety of alien organisms, including headcrabs, bullsquids, Vortigaunts, and headcrab zombies, as well as human opponents such as military soldiers and Black Ops assassins. Human enemies were noted for their use of coordinated behavior and tactical responses, while different alien species possess distinct methods of attacking the player. Valve demonstrated AI features such as fear and group behavior during the game's development, contributing to encounters in which enemies could react to the player's actions rather than simply attacking from predetermined positions.
Sources: en.wikipedia.org
In the months and years following the appearance of pubic hair, other areas of skin that respond to androgens may develop androgenic hair. The usual sequence is: underarm (axillary) hair, perianal hair, upper lip hair, sideburn (preauricular) hair, periareolar hair, and the beard area. As with most human biological processes, this specific order may vary among some individuals. Arm, leg, chest, abdominal, and back hair become heavier more gradually. There is a large range in amount of body hair among adult men, and significant differences in timing and quantity of hair growth among different racial groups. Facial hair is often present in late adolescence, but may not appear until significantly later. Facial hair will continue to get coarser, darker and thicker for another 2–4 years after puberty. Some men do not develop full facial hair for up to 10 years after the completion of puberty.
NOS Events – The NOS is also responsible for broadcasting live special events, such as breaking news, weddings of the Dutch royal family, and the Dutch elections. (This department was called NOS Actueel, but that name is defunct since on 1 January 2006 NOS RTV changed its corporate identity) Nieuwsuur (Newshour) – Co-produced with the NTR, the NOS provides news and political affairs coverage for NPO 2's nightly hour-long news magazine programme.
The molecules that contribute vitamin E activity are four tocopherols and four tocotrienols, within each group of four identified by the prefixes alpha- (α-), beta- (β-), gamma- (γ-), and delta- (δ-). For alpha(α)-tocopherol each of the three "R" sites has a methyl group (CH3) attached. For beta(β)-tocopherol: R1 = methyl group, R2 = H, R3 = methyl group. For gamma(γ)-tocopherol: R1 = H, R2 = methyl group, R3 = methyl group. For delta(δ)-tocopherol: R1 = H, R2 = H, R3 = methyl group. The same configurations exist for the tocotrienols, except that the unsaturated side chain has three carbon-carbon double bonds whereas the tocopherols have a saturated side chain. (Esters such as alpha-tocopherol acetate are digested in the human body to yield the corresponding tocopherol.) Nutritional labeling only takes into account the α-tocopherol form because the human liver preferentially retains this form due to the structure of alpha-tocopherol transfer protein. This form is present in much higher amounts in blood plasma than other forms, and it is known to cover the dietary requirement of vitamin E. The other forms are not considered essential.
=== Queen's Fire Services Medal (QFSM) === England and Wales Peter John Dale, Chief Fire Officer, Staffordshire Fire Service. Alan Kenneth Dixon, Assistant Divisional Officer, Cleveland Fire Brigade. Kenneth George Monk, lately Chief Fire Officer, Derbyshire Fire Service. Alan Keith Seaman, lately Temporary Chief Fire Officer, South Yorkshire Fire Service. Scotland John Clenaghan, Divisional Officer Grade 1, Strathclyde Fire Brigade. Alexander James Lobban, Firemaster, Grampian Fire Brigade. Northern Ireland Raymond Moore, Assistant Chief Fire Officer, Northern Ireland Fire Brigade. Overseas Lam Chun-man, Chief Fire Officer, Royal Hong Kong Fire Service.
== Adverse effects == The New England Journal of Medicine published two editorials in 2003 expressing concern about off-label uses of HGH and the proliferation of advertisements for "HGH-Releasing" dietary supplements, and emphasized that there is no evidence that use of HGH in healthy adults or in geriatric patients is safe and effective – and especially emphasized that risks of long-term HGH treatment are unknown. One editorial was by Jeffrey M. Drazen, M.D., the editor-in-chief of the journal; the other one was by Mary Lee Vance, who provided the NEJM's editorial original, cautious comment on a much cited 1990 study on the use of HGH in geriatric patients with low growth hormone levels. A small but controlled study of GH given to severely ill adults in an intensive care unit setting for the purpose of increasing strength and reducing the muscle wasting of critical illness showed a higher mortality rate for the patients having received GH. The reason is unknown, but GH is now rarely used in ICU patients unless they have severe growth hormone deficiency. GH treatment usually decreases insulin sensitivity, but some studies showed no evidence for increased diabetes incidence in GH-treated adult hypopituitary patients. In past it was believed that GH treatment could increase the cancer risk; a large study recently concluded that "With relatively short follow-up, the overall primary cancer risk in 6840 patients receiving GH as adults was not increased.
Sources: en.wikipedia.org
It binds and activates both the GIP and GLP-1 receptors, making it a dual incretin receptor agonist. Single-receptor GLP-1 agonists act on one target only. The dual profile is the defining pharmacological feature of the molecule.
A fatty diacid side chain promotes reversible binding to serum albumin. This association slows renal clearance and protects the peptide from rapid enzymatic degradation. The result is a prolonged circulation time that supports weekly administration.
The first regulatory approval, for type 2 diabetes, was granted in the United States in 2022. An additional approval for chronic weight management followed in 2023. Availability and approved indications vary by country and are set by each national regulator.
It is a synthetic peptide that activates both the GIP and GLP-1 receptors, making it a dual agonist. Approved products are given by injection rather than by mouth. It is not a small molecule and does not belong to the older sulfonylurea or thiazolidinedione families.