deamidation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-30. Anything still debated is marked as such rather than presented as settled.
Ipamorelin 是一种合成五肽，序列为 Aib-His-D-2-Nal-D-Phe-Lys-NH2，分子式 C38H49N9O5，游离碱分子量约 711.85 g/mol。它属于生长激素促分泌素（GHS）家族，作用靶点是胃饥饿素受体 GHS-R1a。该化合物由诺和诺德的研究团队在二十世纪九十年代末报道，设计目标是提高对生长激素释放的选择性。C 端酰胺化与 N 端 Aib 残基是两个用于抵抗肽酶降解的结构特征。
在 GHS 家族中，早期肽类如 GHRP-6 与 GHRP-2 会同时促进生长激素、皮质醇与催乳素的释放，并明显增加食欲。Ipamorelin 在动物与早期人体研究中表现出对生长激素释放的相对选择性，对上述其他激素的影响较小。这种差异通常归因于受体结合模式与下游信号偏向的不同，而完整的分子解释仍有待补充。需要区分的是，选择性是研究观察中的相对程度，并非绝对界限。
从用途定位看，ipamorelin 目前主要以研究用肽的身份被讨论，未见主要药品监管机构将其批准为治疗药物。市售材料通常标注仅供研究使用，不得用于人体或诊断程序。文献中它常与生长激素促分泌素、GHS-R1a 激动剂、胃饥饿素拟似物等表述并列出现。既有研究的样本量普遍偏小，因此对其效应强度与一致性的描述应保持谨慎。
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor type 1a, the same G protein-coupled receptor that binds ghrelin. Receptor activation couples to Gq/11 signaling, raising intracellular calcium through inositol trisphosphate and diacylglycerol, which in turn promotes exocytosis of growth hormone from pituitary somatotroph cells. Ipamorelin binds this receptor with high affinity and shows weak activity at other secretagogue-related targets in vitro. Its action requires the intact receptor and is not reversed by growth hormone-releasing hormone antagonists.
Compared with earlier growth hormone secretagogues such as GHRP-6 and hexarelin, ipamorelin has been reported to produce less stimulation of adrenocorticotropic hormone, cortisol, and prolactin in animal and early human studies. This selectivity is usually attributed to differences in receptor subtype interactions and to the tissue distribution of the receptor. Effects on appetite appear weaker than those of ghrelin itself, although the supporting evidence base is small. Whether these differences produce a distinct clinical profile remains an open question, since controlled human trials are limited.
Ipamorelin is a synthetic pentapeptide first described in the 1990s by researchers at Novo Nordisk during a program to develop selective growth hormone secretagogues. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues, alpha-aminoisobutyric acid and D-2-naphthylalanine. The C-terminus is amidated, and the material is supplied as a white lyophilized powder. The molecular formula is C38H49N9O5 and the monoisotopic mass is approximately 711.85 daltons. The short chain and modified residues give it greater resistance to enzymatic degradation than many larger peptide hormones.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C38H49N9O5 | 五肽，C 端酰胺化 |
| 分子量 | 约 711.85 g/mol | 游离碱形式 |
| 外观 | 白色至类白色冻干粉 | 研究用材料的常见形态 |
| 溶解性 | 溶于水及 DMSO 等极性溶剂 | 建议现配现用 |
| 储存温度 | -20 °C 或更低 | 干燥、避光、限制冻融次数 |
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue family. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, and its molecular mass is approximately 711.9 daltons. The compound was described in the late 1990s by researchers seeking molecules that release growth hormone with fewer side effects than earlier secretagogues. It is a laboratory and research compound, not an approved medicine in most jurisdictions.
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor, also called the ghrelin receptor or GHS-R1a. Binding to this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to growth hormone release. The effect is mediated through phospholipase C and calcium mobilization rather than through the cyclic AMP pathway used by growth hormone releasing hormone. The two pathways are complementary, and combined stimulation produces a larger response than either alone.
Compared with other secretagogues such as GHRP-2, GHRP-6, and hexarelin, ipamorelin is described as more selective. Published animal work reports little or no increase in adrenocorticotropic hormone, cortisol, or prolactin at doses that release growth hormone. This selectivity is the property most often cited in the research literature. Whether the same profile holds across species and dosing schedules remains an open question, since human data are limited and come largely from small studies.
Lyophilized ipamorelin powder is the form usually supplied for laboratory work. Kept dry, protected from light, and held at minus 20 degrees Celsius or below, it remains stable for extended periods, often measured in years. Once dissolved, the peptide degrades faster through hydrolysis, oxidation, and deamidation, so solutions are typically refrigerated and used within weeks. Repeated freeze-thaw cycles and exposure to alkaline conditions accelerate loss of the parent compound.
Reversed-phase high-performance liquid chromatography is the standard tool for assessing purity. Detection near 214 nanometers captures the peptide backbone, and the resulting chromatogram shows the main peak alongside related impurities. Electrospray ionization mass spectrometry confirms molecular mass and supports sequence verification. Common degradation products include oxidized residues, deamidated forms, and truncated fragments, each appearing as a distinct peak or shoulder in the trace.
Quality claims for research peptides vary widely across suppliers. A certificate of analysis should list purity by chromatography, the mass found by spectrometry, and the analytical conditions used. Independent testing at a third-party laboratory is a common way to check identity and purity, because documents alone cannot confirm what is inside a vial. Purity figures describe the proportion of the target peptide among detected species, and they say nothing about biological activity or sterility.
=== Prevention === Prevention relies on a farm to plate approach involving the whole supply chain anchored in risk analysis and good hygiene practices. Internationally, the Codex Alimentarius General Principles of Food Hygiene provide the foundation for national food safety systems and industry controls. These guidelines are then implemented through various prerequisite programs and HACCP (Hazard Analysis and Critical Control Point) which identify, monitor, and control hazards at specific steps in production. For consumers and food service businesses, evidence-based guidance involves four key steps: Clean, Separate, Cook, Chill. These techniques reduce cross-contamination and ensure lethal heat treatment and rapid refrigeration. Since supply chains are complex, it is critical to prioritize monitoring high-risk foods, such as minimally processed fresh produce, and modifying controls such as, agricultural water safety, manure management, worker hygiene, and post-harvest sanitation. Overall, strengthening surveillance and rapid information-sharing through a One Health lens by linking human, animal, and environmental data, improves outbreak detection and targeted interventions. This is a priority of the WHO Global Strategy for Food Safety 2022–2030.
The production was held at the Eugene O'Neill Theatre in New York City to raise money for the American Foundation for Equal Rights. Freeman had a lead role in the 2012 drama The Magic of Belle Isle, as an alcoholic novelist trying to write again. The film fared poorly with critics, gaining only a 29% approval rating on Rotten Tomatoes. Lastly in 2012, Freeman reprised his role as Lucius Fox for the third time in The Dark Knight Rises. A number of box office hits were released in 2013. Freeman appeared in the action-thriller Olympus Has Fallen, the first installment in what would become the Has Fallen film series; he portrays Speaker of the House Allan Trumbull. The San Francisco Chronicle critic gave Olympus Has Fallen 3 out of 4 stars and opined that Freeman gave an amicable supporting performance. He then starred in the science fiction drama Oblivion, with co-star Tom Cruise, as veteran soldier Malcolm Beech, and appeared in the thriller Now You See Me, as an ex-magician. Lastly, he played a retiree in Last Vegas, with co-stars Michael Douglas, Robert De Niro, Kevin Kline, and Mary Steenburgen. Filmed in Las Vegas and Atlanta, Last Vegas was praised for its cast's chemistry, and one critic thought Freeman brought the most amusement. In 2014, Freeman voiced the character Vitruvius in The Lego Movie, a commercially successful 3D animation. He starred in Transcendence, a science fiction thriller directed by Wally Pfister in his directorial debut, in which Freeman plays scientist Joseph Tagger. Critic reviews of the film were generally mixed, according to Metacritic.
==== Research and traditional medicine ==== Preliminary research indicates that the phytochemicals, betulin and possibly other triterpenes, are active in Episalvan gel and wound healing properties of birch bark. Over centuries, birch bark was used in traditional medicine practices by North American indigenous people for treating superficial wounds by applying bark directly to the skin. Splints made with birch bark were used as casts for broken limbs in the 16th century.
=== Artificial retina === The artificial retina of Professor José Sahel and his team at the Quinze-Vingts National Ophthalmology Hospital Centre aims to allow people with degenerative retinal disease, numbering 1.5 million in 2008, to accomplish everyday activities. Placed under the existing retina, it directly stimulates the neurons, replacing defective cells. These implants should eventually allow patients to recognize faces, read large print and move independently in a restricted environment. The challenge for the Altran teams was to find solutions to produce artificial retina in series, in order to bring solutions to the widest number of patients.
Sources: en.wikipedia.org
== Further reading == Watkins, Steve (29 June 2018). "Which Cincinnati public company CEO delivers the best bang for the buck? (Video)". Cincinnati Business Courier. American City Business Journals. Retrieved 31 Aug 2019. It's rare to see a CEO make less money than a CFO or an executive vice president. But that's how it worked last year at Medpace Holdings Inc....
=== Chemi-ionization === Chemi-ionization is the formation of an ion through the reaction of a gas phase atom or molecule with an atom or molecule in an excited state. Chemi-ionization can be represented by
Modern units use a magnetic door gasket that holds the door sealed but allows it to be pushed open from the inside. This gasket was invented, developed and manufactured by Max Baermann (1903–1984) of Bergisch Gladbach/Germany. Regarding total life-cycle costs, many governments offer incentives to encourage recycling of old refrigerators. One example is the Phoenix refrigerator program launched in Australia. This government incentive picked up old refrigerators, paying their owners for "donating" the refrigerator. The refrigerator was then refurbished, with new door seals, a thorough cleaning, and the removal of items such as the cover that is strapped to the back of many older units. The resulting refrigerators, now over 10% more efficient, were then given to low-income families. The United States also has a program for collecting and replacing older, less-efficient refrigerators and other white goods. These programs seek to replace large appliances that are old and inefficient or faulty by newer, more energy-efficient appliances, to reduce the cost imposed on lower-income families, and reduce pollution caused by the older appliances.
Sources: en.wikipedia.org
两者都是 GHS-R1a 激动剂，但 ipamorelin 在研究中显示出更高的生长激素释放选择性。早期资料显示它对皮质醇、催乳素与食欲的刺激弱于 GHRP-6。这些差异是相对程度，而非绝对区分。
公开资料中它主要以研究用肽的形式出现，未获主要监管机构批准用于治疗。可得材料通常标注仅供研究使用。任何临床用途的宣称都缺少监管依据。
序列中的 Aib 与 D-2-Nal 等非天然残基可提高对肽酶的抵抗能力，并影响受体结合的构象。这类修饰在合成肽设计中较为常见。它们也使常规氨基酸分析需要额外步骤才能确认序列。
Aib 即 α-氨基异丁酸，是一种非蛋白质源氨基酸，其侧链为两个甲基。它在肽链中倾向于诱导螺旋构象并限制骨架的柔性。这种刚性被认为有助于抵抗蛋白酶切割。