This is a working overview of body composition, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-18 and is reviewed periodically as new material appears.
临床研究通常测量体重、腰围、空腹血糖、糖化血红蛋白和血脂,并记录不良事件。药代动力学评估关注浓度-时间曲线,药效动力学评估关注代谢标志物变化。体重下降由能量摄入减少、能量消耗变化和脂肪组织重塑共同造成,具体权重仍不明确。研究之间的终点定义和随访时长差异使横向比较复杂。
瑞他鲁肽同时激活GLP-1受体、GIP受体和胰高血糖素受体,这三者均属于B类G蛋白偶联受体。受体激活后主要经cAMP信号通路传递效应。GLP-1成分与食欲抑制和胃排空延缓相关,GIP成分影响脂肪组织与胰岛素分泌,胰高血糖素成分则促进肝糖输出和能量消耗。各受体贡献的相对比例在人体中尚未完全量化。
Development has progressed from single- and multiple-ascending-dose studies in healthy volunteers into larger randomized trials in adults with obesity, type 2 diabetes, and fatty liver disease. Early reports describe dose-dependent reductions in body weight and improvements in glycemic markers over treatment periods of several months. Whether the glucagon arm adds tolerability cost without added benefit is still debated. Long-term cardiovascular outcomes, effects after treatment stops, and performance in older or comorbid populations are open questions rather than settled findings. Approval status may change, so the current investigational label should be confirmed against regulatory sources.
Retatrutide is an investigational synthetic peptide developed under the code LY3437943, with a backbone derived from glucose-dependent insulinotropic polypeptide. Several non-proteinogenic residues, including alpha-aminoisobutyric acid, appear in that backbone, and a fatty diacid side chain attached through a linker extends circulation time. The molecule carries roughly thirty-nine amino acid units and a total mass near 4.7 kilodaltons. Administration is by subcutaneous injection once weekly. Published work uses both the name retatrutide and the code LY3437943.
Pharmacologically the compound activates three receptors: GLP-1, GIP, and glucagon. GLP-1 and GIP signaling contribute to glucose-dependent insulin release, delayed gastric emptying, and reduced appetite, while glucagon receptor activation is associated with increased energy expenditure and hepatic fat oxidation. The single-molecule design is intended to keep these activities in one peptide rather than combining separate agents. Relative activity at each receptor differs, and the balance between them is a central question in interpretation. The glucagon component is partly offset by incretin-mediated insulin secretion, an interaction that remains incompletely characterized.
| Property | Value | Notes |
|---|---|---|
| 分子量 | 约4.7 kDa | 合成肽,具体数值随形式而变化 |
| 外观 | 白色至类白色冻干粉 | 常见于多肽制剂 |
| 溶解度类别 | 水溶性 | 可溶于水性缓冲液,pH影响溶解 |
| 典型储存温度 | -20°C或更低 | 冻干粉长期保存 |
| 典型分析方法 | 反相高效液相色谱与质谱 | 用于纯度、身份和杂质分析 |
Characterization panels may add amino acid analysis for compositional confirmation, circular dichroism for secondary structure in solution, and light scattering for aggregation tendency. Aggregation is a central concern for peptides bearing hydrophobic side chains, since it can lower measured potency and complicate accurate dosing. Stability studies examine temperature, humidity, pH, and light exposure over defined intervals, reporting the percentage of intact peptide remaining. Results depend strongly on the assay used, so comparing values across studies requires matching method details.
Peptide content and purity are commonly measured by reversed-phase high-performance liquid chromatography with ultraviolet detection, using gradient elution over a C18 column. Identity is confirmed by mass spectrometry, because the theoretical monoisotopic mass allows unambiguous assignment of the main component. Impurity profiling resolves deletion sequences, oxidized residues, and truncated fragments. Since the molecule carries a lipophilic side chain, mobile phases often include ion-pairing agents and organic modifiers to keep peaks symmetric.
Lyophilized material is generally held at minus 20 degrees Celsius or colder for long-term storage, protected from moisture and light. Solutions are handled under refrigeration, typically between 2 and 8 degrees Celsius, and used within a short window because degradation and microbial growth both accelerate in liquid. Repeated freeze-thaw cycles are avoided, and vials are equilibrated to room temperature before opening to reduce condensation. These are general laboratory conventions for peptides of this size rather than product-specific directions.
Published information places retatrutide in clinical development rather than on the market as an approved therapy. Early-stage and mid-stage trials have examined tolerability and changes in body weight, and larger studies continue to report results over time. Open questions include the durability of effects after treatment stops, the composition of weight lost, and cardiovascular outcomes over long periods. Statements about definitive benefit should therefore be treated as provisional. Regulatory status varies by jurisdiction and changes as applications are reviewed.
Retatrutide is an investigational synthetic peptide designed to activate three distinct receptor systems within a single molecule. Its pharmacological profile combines activity at the glucose-dependent insulinotropic polypeptide receptor, the glucagon-like peptide-1 receptor, and the glucagon receptor. This arrangement places it within a broader class of agents often described as multi-agonists, which contrast with compounds that engage one or two targets. Research interest centers on whether simultaneous signaling produces effects that single-receptor agonists cannot achieve alone. A single molecular entity also simplifies manufacturing and delivery logistics compared with combining separate agents.
Mechanistic proposals link each receptor to a different physiological role. Activation of the glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors is associated with reduced appetite, slower gastric emptying, and glucose-dependent insulin release. Glucagon receptor signaling, by contrast, is associated with increased energy expenditure and altered lipid handling, though it can also raise blood glucose. The design intent is to balance these contributions so that weight reduction is enhanced without unacceptable glycemic trade-offs. How well that balance holds across individuals is not fully resolved.
Body composition is assessed with dual-energy X-ray absorptiometry or comparable methods, which separate fat mass from lean mass. Reported losses include both compartments, and the ratio between them is a subject of ongoing analysis rather than a settled result. Waist circumference, blood pressure, and lipid panels are collected as supporting measures. Resting energy expenditure and substrate oxidation are measured in smaller mechanistic studies, where glucagon receptor activity is expected to matter. These substudies are typically short and small, so their findings carry wide uncertainty.
Interpretation depends on study phase and duration. Phase 2 programs are powered for weight and safety signals, not for cardiovascular or renal outcomes, which require event-driven designs. Gastrointestinal events such as nausea, diarrhea, vomiting, and constipation are the most frequently reported adverse effects and tend to cluster around dose escalation. Small increases in heart rate have been described. Because follow-up after treatment discontinuation is limited, questions about weight regain and durability are open rather than answered.
Trial reports for this compound rely on a small set of repeated measures. Body weight is normally expressed as percent change from baseline at a fixed week, with absolute kilograms given secondarily. Glycemic endpoints include HbA1c, fasting glucose, and, in some protocols, continuous glucose monitoring summaries. Imaging endpoints such as MRI-derived proton density fat fraction quantify liver fat. Standardization matters because a percent change and a categorical responder analysis can tell different stories about the same dataset.
Robert Shonov, who worked in the US consulate in Vladivostok before being subcontracted to summarize Russian media reports for the embassy in Moscow was arrested, charged with cooperating "on a confidential basis with a foreign state, [or] international or foreign organisation", and detained at Lefortovo Prison. The State Department said the allegations were without merit. The FSB later said it had charged Shonov for “confidential collaboration” with a foreign state, allegedly collecting information on the Russian war effort in Ukraine, its military draft and protest activities in the run-up to the 2024 presidential elections. Hungary blocked the disbursement of an upcoming tranche of military support for Ukraine provided under the European Union's European Peace Facility (EPF), arguing that the fund was too focused on Ukraine and that the funds could be used elsewhere. Hungarian Foreign Minister Peter Szijjarto previously said that the country would block the disbursement as well as any new sanctions package on Russia until Ukraine removed OTP Bank, Hungary's largest commercial bank, in the list of sponsors of the war in Ukraine due to the position of the bank's management to continue operations in Russia and its client republics in the Donbas, which itself was based on a decision by the National Agency for the Prevention of Corruption of Ukraine. Hungary also demanded the removal of three people from a new sanctions list proposed by the European Commission as part of the 11th package of sanctions against Russia.
Transforming growth factor beta-3 is a protein that in humans is encoded by the TGFB3 gene. It is a type of protein, known as a cytokine, which is involved in cell differentiation, embryogenesis and development. It belongs to a large family of cytokines called the Transforming growth factor beta superfamily, which includes the TGF-β family, Bone morphogenetic proteins (BMPs), growth and differentiation factors (GDFs), inhibins and activins. TGF-β3 is believed to regulate molecules involved in cellular adhesion and extracellular matrix (ECM) formation during the process of palate development. Without TGF-β3, mammals develop a deformity known as a cleft palate. This is caused by failure of epithelial cells in both sides of the developing palate to fuse. TGF-β3 also plays an essential role in controlling the development of lungs in mammals, by also regulating cell adhesion and ECM formation in this tissue, and controls wound healing by regulating the movements of epidermal and dermal cells in injured skin.
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28. Fatty acids are a major component of the lipids (up to 70% by weight) in some species such as microalgae but in some other organisms are not found in their standalone form, but instead exist as three main classes of esters: triglycerides, phospholipids, and cholesteryl esters. In any of these forms, fatty acids are both important dietary sources of fuel for animals and important structural components for cells.
The Bloomberg tablets are a collection of 405 preserved wooden tablets that were found at the site of the Bloomberg building in the financial district of London. Excavations of the site took place between 2010 and 2013, after which the current Bloomberg building was constructed on the site of the archaeological dig. The tablets are the earliest written documents found in Britain, dating from 50 to 80 AD in the early Roman period. These tablets predate the Vindolanda tablets, which were previously the earliest writing examples found in Britain, dating to 100 AD or later.
== Clinical significance == The insulin oscillations are particularly pronounced in the portal vein delivering blood from the pancreas to the liver, which is a major insulin target. Disturbances of the insulin oscillations occur early in type 2 diabetes and may contribute to insulin resistance. Pulsatile insulin delivery to the portal vein or islet cell transplantation to the liver of diabetic patients are therefore attractive therapeutic alternatives.
Sources: en.wikipedia.org
=== Role in melanoma metastasis === Heavily pigmented melanoma cells have a Young's modulus of about 4.93 kPa, compared to non-pigmented cells, with a value of 0.98 kPa. The elasticity of melanoma cells is crucial to metastasis and growth; non-pigmented tumors were larger than pigmented tumors, and spread far more easily. Pigmented and non-pigmented cells are both present in melanoma tumors, so that they can both be drug-resistant and metastatic.
=== Disorders involving the immune mechanism === 279 Disorders involving the immune mechanism 279.0 Deficiency of humoral immunity 279.00 Hypogammaglobulinemia unspecified 279.01 Selective IgA immunodeficiency 279.02 Selective IgM immunodeficiency 279.03 Other selective immunoglobulin deficiencies 279.04 Congenital hypogammaglobulinemia 279.05 Immunodeficiency with increased IgM 279.06 Common variable immunodeficiency 279.09 Other deficiency of humoral immunity 279.1 Deficiency of cell-mediated immunity 279.10 Immunodeficiency with predominant t-cell defect unspecified 279.11 DiGeorge syndrome 279.12 Wiskott–Aldrich syndrome 279.13 Nezelof syndrome 279.19 Other deficiency of cell-mediated immunity 279.2 Combined immunity deficiency Severe combined immunodeficiency 279.3 Unspecified immunity deficiency 279.4 Autoimmune disease not elsewhere classified 279.5 Graft-versus-host disease 279.8 Other specified disorders involving the immune mechanism 279.9 Unspecified disorder of immune mechanism
Portal venous systems A portal venous system is a series of veins or venules that directly connect two capillary beds. The two systems in verebrates are the hepatic portal system, and the hypophyseal portal system.
=== Varieties and cultivars === Lotus varieties have been classified according to their use into three types: rhizome lotus, seed lotus, and flower lotus. Varieties that show more than one of these characteristics are classified by the strongest feature. Regarding production area in China, rhizome lotus has the largest area with 200,000 ha (490,000 acres), followed by seed lotus with 20,000 ha (49,000 acres).
21 March A Kon Tum Province refugee center was attacked for the second time by a PAVN battalion using mortars and B-40 rockets. Seventeen civilians were killed and 36 wounded, many of them women and children. A third of the center was destroyed.
Sources: en.wikipedia.org
意味着单个分子可同时结合三种代谢受体,而不是只作用于一种。其目的是整合食欲、胰岛素和能量消耗通路,但人体中的协同程度仍在研究。
不是。研究还评估血糖控制、肝脏脂肪、血脂和心血管风险标志物。不同终点的证据成熟度不同。
胰高血糖素成分在人体中的净效应存在争议,因为它可能升高血糖,也可能增加能量消耗。长期平衡和个体差异尚未明确。
As of the mid-2020s retatrutide remains investigational and is not an approved medicine in the United States or the European Union. It has been supplied mainly to participants in clinical trials. Labels and availability can change, so regulatory listings should be checked directly.