The short version of 非天然氨基酸 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-06-23. 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.
| 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 |
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.
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.
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.
Research quantities of ipamorelin are typically distributed as a white to off-white lyophilized powder. The solid dissolves readily in water and in aqueous buffers, and stock solutions are commonly prepared in sterile water or a mildly acidic diluent. Adsorption to plastic and glass surfaces can reduce the concentration of very dilute solutions, so containers and transfer steps deserve attention when accurate concentrations matter. Reconstituted material is generally used promptly rather than held for extended periods.
Storage recommendations for the dry solid center on low temperature and low moisture, most often -20 °C in a sealed, desiccated container protected from light. Solutions are less stable than the powder and are usually kept cold and used within a short window. Freeze-thaw cycling is a recognized source of loss, and aliquoting before freezing is a standard precaution. These practices derive from general peptide handling principles rather than from a single published stability trial, so exact shelf lives should be treated as approximate.
Body fat cells have regional responses to the overfeeding that was studied in adult subjects. In the upper body, an increase of adipocyte size correlated with upper-body fat gain; however, the number of fat cells was not significantly changed. In contrast to the upper body fat cell response, the number of lower-body adipocytes did significantly increase during the course of experiment. Notably, there was no change in the size of the lower-body adipocytes. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index without a significant increase in the overall number of adipocytes in adulthood.
=== Endocrine === Dexamethasone is the treatment for the very rare disorder of glucocorticoid resistance. In adrenal insufficiency and Addison's disease, dexamethasone is prescribed when the patient does not respond well to prednisone or methylprednisolone. It can be used in congenital adrenal hyperplasia in older adolescents and adults to suppress adrenocorticotropic hormone (ACTH) production. It is typically given at night.
Guttenplan (1978), London correspondent and current editor of The Nation Michael Musto (1978), gossip columnist for The Village Voice Andrea di Robilant (1979), Italian journalist for La Stampa and professore Tim Weiner (1979), Pulitzer Prize-winning reporter for The New York Times specializing in national security matters Kevin Baker (1980), freelance journalist and novelist John Leland (1981), journalist for The New York Times Jason Zweig (1982), financial journalist and columnist for The Wall Street Journal Barry C. Lynn (1983), journalist, senior fellow at the New America Foundation Ashley Kahn (1983), Grammy-winning music historian, journalist, and producer Daniel Wattenberg (1983), journalist for The Washington Times, son of neoconservative pundit Ben J. Wattenberg N.J.
== Further reading == Bachner, Paul (2021). In further pursuit of excellence: the college of American pathologists 1946-2020 (PDF) (1st ed.). Northfield: College of American Pathologists. ISBN 978-1-941096-61-1.
Sources: en.wikipedia.org
== Veterinary uses == A number of veterinary medicine teaching hospitals are participating in a long-term clinical study examining the effect of rapamycin on the longevity of dogs. A clinical trial led by NC State College of Veterinary Medicine (HALT), run at a number of veterinary hospitals across the US, found that rapamycin reverses the effects of hypertrophic cardiomyopathy in cats. In March 2025, the US Food and Drug Administration announced conditional approval of sirolimus delayed-release tablets (Felycin-CA1) for the management of ventricular hypertrophy in cats with subclinical hypertrophic cardiomyopathy. This is the first product approved for use in cats with hypertrophic cardiomyopathy for any indication. Cardiomyopathy is a disease of the heart muscle. Hypertrophic cardiomyopathy in cats causes thickening of the heart's left ventricle. It is the most common heart disease in cats and is one of the most common causes of death in cats. While the cause is unknown in most cases, hypertrophic cardiomyopathy is associated with a genetic mutation in certain breeds, such as Maine Coons, Ragdolls, and Persians. Hypertrophic cardiomyopathy is a progressive disease. Cats in the subclinical phase have thickening of their heart wall but do not show clinical symptoms of the disease yet. Cats may live for years in the subclinical phase, while others may progress to congestive heart failure, arterial thromboembolism, or sudden death.
== Regulation == In the European Union, regulations include the species of coffee bean, geographical origin, processing detail, year of crop, solvents used in decaffeination, and caffeine level. Various institutions govern the coffee industry and help to achieve standardization and release information to the public, including the International Coffee Organization (London), Codex Alimentarius Commission of the UN (Rome), and National Coffee Association (New York).
US and South African justification for arming UNITA lay partly in the increased supply by the Soviet Union of more sophisticated weapons to FAPLA, as well as the increased number of Cuban troops in Angola, which had rapidly swelled from 25,000 to 31,000 by the end of 1985. While the Lusaka Accords were still in force, the Cuban and Soviet military delegations had urged dos Santos to take advantage of the ceasefire with the SADF to eliminate UNITA. There was a considerable increase in Soviet military assistance to Angola during this period, with the transfer of another billion dollars' worth of arms to FAPLA, including about 200 new T-55 and T-62 tanks. Moscow trained more Angolan pilots and delivered more advanced fighter aircraft to Luanda, particularly Mikoyan-Gurevich MiG-23s. Over a three year period Angola had become the second largest importer of arms on the African continent. FAPLA's arsenal expanded so exponentially that the SADF became convinced that the Soviet-sponsored arms buildup was intended for deployment elsewhere. General Malan gave a speech in which he expressed alarm at the "flood" of Soviet military equipment and its sophisticated nature, claiming that it was much more than needed to cope with the SADF's limited expeditionary forces and UNITA. Malan theorised that "the Russians want to develop a strong, stabilised base in Angola and then use the equipment and personnel positioned there wherever necessary in the subcontinent".
nucleic acid sequence The precise order of consecutively linked nucleotides in a nucleic acid molecule such as DNA or RNA. Long sequences of nucleotides are the principal means by which biological systems store genetic information, and therefore the accurate replication, transcription, and translation of such sequences is of the utmost importance, lest the information be lost or corrupted. Nucleic acid sequences may be equivalently referred to as sequences of nucleotides, nitrogenous bases, nucleobases, or, in duplex molecules, base pairs, and they correspond directly to sequences of codons and amino acids.
A general synthetic route to organomercury compounds entails alkylation with Grignard reagents and organolithium compounds. Diethylmercury results from the reaction of mercury chloride with two equivalents of ethylmagnesium bromide, a conversion typically conducted in diethyl ether solution. Similarly, diphenylmercury can be prepared by reaction of mercury chloride and phenylmagnesium bromide. A related preparation entails formation of phenylsodium in the presence of mercury(II) salts. Hg(II) can be alkylated by treatment with diazonium salts in the presence of copper metal. In this way 2-chloromercuri-naphthalene has been prepared. 4-Chloromercuritoluene is obtained by the chloromercuration of sodium toluenesulfinite:
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。