This is a working overview of Ghrelin receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-02-03. Anything still debated is marked as such rather than presented as settled.
The compound was developed at Novo Nordisk during the 1990s as part of a programme seeking secretagogues with improved selectivity. It was described in the peer-reviewed literature in 1998 alongside related pentapeptides from the same series. Investigators advanced it because it raised growth hormone output in animal models while leaving other pituitary hormones comparatively unaffected. The development code NNC 26-0161 appears in earlier reports, and ipamorelin later became the common designation in published work.
Selectivity is the property most often attached to this peptide. Published animal and early human studies record increases in growth hormone release after administration, with adrenocorticotropic hormone and cortisol responses remaining small by comparison. Effects on appetite-related pathways also appear weaker than those reported for several earlier secretagogues. Reviews that compare members of the growth hormone secretagogue family cite these findings frequently, though the receptor-level explanation for the selectivity continues to be debated rather than settled.
Ipamorelin is a synthetic pentapeptide classified as a growth hormone secretagogue. Its sequence, Aib-His-D-2-Nal-D-Phe-Lys-NH2, combines three non-proteinogenic residues with a C-terminal amide. The N-terminal aminoisobutyric acid unit and the two aromatic D-amino acids distinguish it from peptides assembled only from standard L-amino acids. Its formula is C38H49N9O5, corresponding to an average mass near 711.9 Da. At neutral pH the molecule carries a net positive charge, a property that shapes its behaviour in chromatographic and electrophoretic systems.
对 ipamorelin 的常规表征以反相高效液相色谱测定纯度，检测波长多设为 214 nm，因为肽键在该波长有较强吸收。身份确认通常借助电喷雾电离质谱或串联质谱，将实测分子量与理论值逐项比对。序列层面可用肽图分析或氨基酸分析进一步验证。这些手段组合起来，可以分别覆盖纯度、身份与序列三个不同层次的信息。
杂质谱一般包含缺失序列片段、差向异构体、氧化产物以及残留溶剂或反离子，其中组氨酸与芳香残基的氧化常被重点关注。反相色谱中这类杂质往往紧邻主峰洗脱，因此方法需要足够的分离度并经过系统适用性验证。纯度百分比的解读依赖于检测波长与梯度条件，不同实验室公布的数字不宜直接横向比较。参考标准品有助于跨批次对照，但其自身赋值同样需要可追溯来源。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H49N9O5 | Pentapeptide with C-terminal amide |
| Average mass | Approximately 711.9 Da | Value derived from the formula |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and aqueous acetonitrile | Dissolution aided by acidic diluents |
| Common synonyms | Ipamorelin; NNC 26-0161 | Code name used in early reports |
At the cellular level, ipamorelin binds the growth hormone secretagogue receptor, also called the ghrelin receptor. Activation of this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to release of growth hormone into circulation. Because release follows a pulsatile pattern, studies often report peak concentration and total area under the curve rather than a single time point. Selectivity for this receptor is the property most frequently discussed in comparative work.
Compared with older secretagogues such as hexarelin or GHRP-6, ipamorelin shows weaker stimulation of cortisol, prolactin, and appetite in the animal models used for early characterization. Whether that selectivity is preserved across longer human exposures remains an open question, because published clinical data are limited in size and duration. Reported effects on food intake are generally described as modest. The compound is therefore treated in the literature as a relatively selective research tool rather than a fully characterized therapeutic agent.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Researchers at a pharmaceutical company first described it in the 1990s while screening small peptides for growth hormone releasing activity. Its chain contains five amino acid residues, two of which are non-natural building blocks, including 2-aminoisobutyric acid and a naphthylalanine derivative. The molecule was designed to act at the ghrelin receptor while avoiding several effects observed with earlier secretagogues.
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.
Analytical confirmation relies on reversed-phase high-performance liquid chromatography, often coupled to mass spectrometry for identity and purity assessment. Mass spectrometry distinguishes the intact molecule from truncation products and from oxidation or deamidation variants that share similar chromatographic retention. Immunoassays appear in some biological studies but can cross-react with related peptides, so they are weaker tools for identity work. Reported purity figures depend heavily on the gradient, detector, and integration method used, which complicates direct comparison between laboratories.
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.
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。
The word(s) of the year, sometimes capitalized as "Word(s) of the Year" and abbreviated "WOTY" (or "WotY"), refers to any of various assessments as to the most important word(s) or expression(s) in the public sphere during a specific year. The German tradition Wort des Jahres was started in 1971. In 1999 it was supplemented with the Austrian word of the year to express the pluricentric nature of German and its multiple standards varieties. The American Dialect Society's Word of the Year is the oldest English-language version, and the only one that is announced after the end of the calendar year, determined by a vote of independent linguists, and not tied to commercial interest. However, various other organizations also announce Words of the Year for a variety of purposes.
A construct in chemistry is molecular symmetry, as embodied in Group theory. Inorganic compounds display a particularly diverse symmetries, so it is logical that Group Theory is intimately associated with inorganic chemistry. Group theory provides the language to describe the shapes of molecules according to their point group symmetry. Group theory also enables factoring and simplification of theoretical calculations. Spectroscopic features are analyzed and described with respect to the symmetry properties of the, inter alia, vibrational or electronic states. Knowledge of the symmetry properties of the ground and excited states allows one to predict the numbers and intensities of absorptions in vibrational and electronic spectra. A classic application of group theory is the prediction of the number of C–O vibrations in substituted metal carbonyl complexes. The most common applications of symmetry to spectroscopy involve vibrational and electronic spectra. Group theory highlights commonalities and differences in the bonding of otherwise disparate species. For example, the metal-based orbitals transform identically for WF6 and W(CO)6, but the energies and populations of these orbitals differ significantly. A similar relationship exists between CO2 and molecular beryllium difluoride.
However, because of how quickly their revolts would further radicalize the lower classes, the Creoles quickly stopped supporting general violent insurrection because they benefitted from social change that occurred through the systems of the Spanish crown. Institutional change ensured stability by supporting the political institutions that allowed for the creation of a wealthy Creole class and further adapting those institutions to meet demands, rather than propose a radical shift in the complete make-up of socioeconomic life and traditions. However, institutional change did not come as anticipated and further spurred on the radicalization of Spanish-American social classes towards independence.
Sources: en.wikipedia.org
== Chemistry == Vancomycin is a branched tricyclic glycosylated nonribosomal peptide produced by the Actinomycetota species Amycolatopsis orientalis (formerly designated Nocardia orientalis). Vancomycin exhibits atropisomerism—it has multiple chemically distinct rotamers owing to the rotational restriction of some of the bonds. The form present in the drug is the thermodynamically more stable conformer.
Theriaca andromachi or Venice Treacle contained 64 ingredients. In addition to viper flesh and opium, it included cinnamon, agarikon and gum arabic. The ingredients were pulverized and reduced to an electuary with honey. The following ingredients for the theriac were taken from the Amsterdammer Apotheek (1683) and translated from the old Latin names into the Latin names now used where possible. Not all ingredients are known, and identifications and assignments below are tentative. Roots: Iris, Balsamorhiza deltoidea, Potentilla reptans (creeping cinquefoil), Rheum rhabarbarum (garden rhubarb), Zingiber officinale, Ulmus × hollandica 'Angustifolia' odorata, Gentiana, Meum athamanticum (spignel), Valeriana, Corydalis cava (hollowroot), glycyrrhiza Stems and barks: Cinnamomum verum (cinnamon), Cinnamomum aromaticum (cassia) Leaves: Teucrium scordium (water germander), Fraxinus excelsior, Clinopodium calamintha (lesser calamint), Marrubium vulgare (white or common horehound), Cymbopogon citratus (West-Indian lemongrass), Teucrium chamaedrys (wall germander), Cupressaceae, Laurus nobilis (bay laurel), Teucrium montanum (mountain germander), Cytinus hypocistis Flowers: Rosa, Crocus sativus, Lavandula stoechas (French lavender), Lavandula angustifolia (common or English lavender), Centaurea minoris (common centaury) Fruits and seeds: Brassica napus (rapeseed), Petroselinum (parsley), Nigella sativa, Pimpinella anisum (anise), Elettaria cardamomum, Foeniculum vulgare (fennel), Hypericum perforatum (St.
However, selegiline can strongly potentiate the reinforcing effects of exogenous β-phenethylamine by inhibiting its MAO-B-mediated metabolism. Misuse of the combination of selegiline and β-phenethylamine has been reported.
Approaches to mitigate inaccurate information and hallucinations include the use of retrieval-augmented generation and "grounding" by configuring the corpus to be used by the AI which is used for example in the open source chatbot "WikiChat" that essentially prevents the hallucinations by retrieving facts only from a multilingual Wikipedia corpus, thereby providing a novel way to use Wikipedias. On 12 August, researchers demonstrate an open source 'AI Scientist' which generates novel research ideas, writes code, executes experiments, and writes a final research paper in the field of machine learning evaluated by an automated reviewer. The authors of the preprint advise "treating generated papers as hints of promising ideas for practitioners to follow up on". On 11 May, a study shows that 52% of ChatGPT answers to 517 programming questions on Stack Overflow contain incorrect information and 77% are verbose where study participants still preferred ChatGPT answers 35% of the time but also overlooked the misinformation in the ChatGPT answers 39% of the time. 10 June – A study finds African elephants use personal name-like calls to address one another. 11 June – Scientists report that serious kidney disease may be associated with human spaceflight. 12 June A study links the apparent gap in life expectancy between male and female organisms to reproductive cells driving sex-dependent differences in lifespan and suggests a role for vitamin D in improving longevity.
Sources: en.wikipedia.org
It is a synthetic five-amino-acid peptide that acts as a growth hormone secretagogue. Three of its residues are non-standard amino acids, and the chain ends in an amide rather than a free acid. The molecule is small enough that it can be characterised by routine peptide analytical techniques.
It has not received marketing approval as a medicine in the United States or the European Union. Supplied material is generally described and handled as a research chemical. Regulatory treatment varies by jurisdiction, and some countries restrict growth hormone secretagogues under sports or medicines legislation.
Earlier secretagogues were associated with broader hormonal responses, including measurable changes in cortisol and prolactin. Reports on this peptide describe a narrower profile in which growth hormone release is the most prominent effect. The observation is influential because it shapes how the compound is compared with other members of the same receptor family.
肽键在 214 nm 附近有较强吸收，适合检测缺少芳香侧链的短肽。该波长的基线受流动相组成与梯度影响较大。因此流动相与梯度条件需要固定并完整记录。