secretagogue is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-10-18. Numbers and descriptions here follow the published literature rather than marketing material.
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。
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。
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.
| 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 |
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.
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.
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.
== Adverse effects == The most common side effects (seen in more than 1% of patients) are upper abdominal (belly) pain, diarrhoea, dry mouth, and nausea or vomiting. Allergic reactions of the skin like itching, rashes, hives and angiooedema are rare. The same is true for anaphylactic shock and convulsions.
== Overdose == Enobosarm has been assessed in clinical trials at doses ranging from 0.1 to 18 mg/day. However, most research has been done at doses of 0.1 to 3 mg/day, with two phase 3 clinical trials using a dosage of 3 mg/day. A few small phase 1 and phase 2 trials of enobosarm for breast cancer have employed doses of 9 to 18 mg/day. Larger, phase 3 trials of enobosarm at a dose of 9 mg/day for breast cancer (e.g., ARTEST, n=210) are now underway. Doses of up to 100 mg have been assessed in single-dose pharmacokinetic studies and doses of up to 30 mg/day have been given in short 14-day pharmacokinetic studies. Enobosarm sold via black-market Internet suppliers and used non-medically is often taken at much higher doses than those used widely in clinical trials (e.g., 10–30 mg/day), with unknown adverse effects and risks.
^ Pesek, J. J.; Matyska, M. T.; Prabhakaran, S. J. (2005). "Synthesis and characterization of chemically bonded stationary phases on hydride surfaces by hydrosilation of alkynes and dienes". Journal of Separation Science. 28 (18): 2437–43. doi:10.1002/jssc.200500249. PMID 16405172. ^ Pesek, J. J.; Matyska, M. T.; Gangakhedkar, S.; Siddiq, R. (2006). "Synthesis and HPLC evaluation of carboxylic acid phases on a hydride surface". Journal of Separation Science. 29 (6): 872–80. doi:10.1002/jssc.200500433. PMID 16830499. ^ Hemström, P.; Irgum, K. (2006). "Hydrophilic interaction chromatography". Journal of Separation Science. 29 (12): 1784–821. doi:10.1002/jssc.200600199. PMID 16970185. ^ C. Kulsing, Y. Nolvachai, P.J. Marriott, R.I. Boysen, M.T. Matyska, J.J. Pesek, M.T.W. Hearn, J. Phys. Chem B, 119 (2015) 3063-3069. ^ J. Soukup, P. Janas, P. Jandera, J. Chromatogr. A, 1286 (2013) 111-118
Bacteria do not have a membrane-bound nucleus, and their genetic material is typically a single circular bacterial chromosome of DNA located in the cytoplasm in an irregularly shaped body called the nucleoid. The nucleoid contains the chromosome with its associated proteins and RNA. Like all other organisms, bacteria contain ribosomes for the production of proteins, but the structure of the bacterial ribosome is different from that of eukaryotes and archaea. Its translation process is also different. Some bacteria produce intracellular nutrient storage granules, such as glycogen, polyphosphate, sulfur or polyhydroxyalkanoates. Bacteria such as the photosynthetic cyanobacteria, produce internal gas vacuoles, which they use to regulate their buoyancy, allowing them to move up or down into water layers with different light intensities and nutrient levels.
Sources: en.wikipedia.org
== External links == Cut-Flower Care — How to Make Your Fresh-Cut Flowers Last by Rose G. Edinger, Brooklyn Botanical Garden, Spring 2003, retrieved October 21, 2006 — What are preserved flowers? Everything you want to know about preserved flowers Archived 2021-01-28 at the Wayback Machine by Floralonly, Albert, published 28, May 2020
Thus, the molar mass of a substance X can be calculated as M(X) = Ar(X) ⋅ Mu, with the molar mass constant Mu equal to exactly 1 Da/ent, which (for all practical purposes) is equal to 1 g/mol, as the mole was historically defined such that the Avogadro number (the number of atomic-scale entities comprising one mole) was exactly equal to the number of daltons in a gram (g/Da). This means that (for all practical purposes): 1 mol = (g/Da) ent. The relationship between the molar mass of carbon-12, M(12C) = 12 g/mol, and its atomic mass, ma(12C) = 12 Da, can be expressed as M(12C) = ma(12C) · NA. Rearranging and substituting the given values into the equation yields the following expression for the Avogadro constant: NA = (g/Da) mol−1, making the Avogadro number equal to the number of daltons in a gram, and equivalently the number of atoms in 12 grams of carbon-12 (as in the 1971 definition of the mole). The mole was defined in such a way that the numerical value of the molar mass of a substance in g/mol, i.e. M(X)/(g/mol), was equal to the numerical value of the average mass of one entity (atom, molecule, formula unit) in Da, i.e. ma(X)/Da = Ar(X), so that M(X) = Ar(X) g/mol. The equivalence was exact before the redefinition of the mole in 2019, and is now only approximate, but equality may still be assumed with high accuracy. Thus, for example, the average mass of a molecule of water is about 18.0153 Da, and the molar mass of water is about 18.0153 g/mol.
Garcia E, Rhee SG (1983). "Cascade control of Escherichia coli glutamine synthetase Purification and properties of PII uridylyltransferase and uridylyl-removing enzyme". J. Biol. Chem. 258 (4): 2246–53. doi:10.1016/S0021-9258(18)32914-4. PMID 6130097. van Heeswijk WC, Rabenberg M, Westerhoff HV, Kahn D (1993). "The genes of the glutamine synthetase adenylylation cascade are not regulated by nitrogen in Escherichia coli". Mol. Microbiol. 9 (3): 443–57. doi:10.1111/j.1365-2958.1993.tb01706.x. PMID 8412694. S2CID 8691388.
== Community engagement and education == Breakthrough T1D offers education and resources, in both English and Spanish, for people of all living with T1D. Some of those who receive support are parents who care for children with T1D, children attending school with T1D, pregnant women with T1D, college students with T1D, and adults with T1D. Whether it is caring for children with T1D, sending children back to school safely, pregnancy and T1D, living with T1D as an adult, college life and T1D, and support groups. Breakthrough T1D also arranges community engagement which allows newly diagnosed families to connect with other T1D families for mutual support.
== Fort Montgomery chain (1776–1777) == In 1776 a chain and boom were stretched across the river from Fort Montgomery on the west bank, at the lower entrance to the Highlands just north of the modern-day Bear Mountain Bridge, to Anthony's Nose on the east bank. Captain Thomas Machin headed the chain effort. In November 1776, a faulty link broke under stress induced by the river current, highlighting some of the difficulties of trying to chain the Hudson. It was repaired and reset. After the British captured forts Montgomery and Clinton, a second fortress built opposite it at the mouth of Popolopen's Kill (today's Popolopen Creek) on its south bank, on October 6, 1777, they dismantled the chain. Free to do so, they raided upriver as far as Kingston, then the capitol of New York State, putting the torch to it and burning all but several of its hundreds of buildings to the ground. Governor George Clinton, a member of the committee assigned by the New York Convention to devise a means of defending the Hudson, was heartened as the British had never attempted to run ships through the chain. He concluded that the basic idea of obstructing the river seemed sound. After Captain Machin recovered from wounds from battle with the British, he began work on the stronger Great Chain at West Point, which was constructed and installed in 1778.
Sources: en.wikipedia.org
Cardiac muscle is involuntary, striated muscle that is found in the walls and the histological foundation of the heart, specifically the myocardium. The cardiac muscle cells, (also called cardiomyocytes or myocardiocytes), predominantly contain only one nucleus, although populations with two to four nuclei do exist. The myocardium is the muscle tissue of the heart and forms a thick middle layer between the outer epicardium layer and the inner endocardium layer. Coordinated contractions of cardiac muscle cells in the heart propel blood out of the atria and ventricles to the blood vessels of the left/body/systemic and right/lungs/pulmonary circulatory systems. This complex mechanism illustrates systole of the heart. Cardiac muscle cells, unlike most other tissues in the body, rely on an available blood and electrical supply to deliver oxygen and nutrients and to remove waste products such as carbon dioxide. The coronary arteries help fulfill this function.
Arginine:glycine amidinotransferase deficiency or AGAT deficiency is an autosomal recessive cerebral creatine deficiency caused by a deficiency of the enzyme arginine:glycine amidinotransferase. This enzyme deficiency results in decreased creatine synthesis, and is caused by biallelic pathogenic variants in GATM. Individuals with AGAT deficiency are intellectually disabled and have muscle weakness. The symptoms of AGAT deficiency are caused by the lack of creatine in specific tissues, most notably muscle and brain. Oral creatine supplementation can be used to treat AGAT deficiency, with early intervention providing the best results. All creatine deficiencies are rare, and there have been fewer than 20 individuals reported in medical literature with AGAT deficiency. This disorder was first described in 2000.
=== 2020 === On 9 March 2020, Sensex tumbled down by 1941.67 points amid the fears of coronavirus pandemic and Yes Bank crisis. This was the second worst single-day fall in the history, where the investors lost ₹6.50 lakh crores ($91 billion). While on 12 March 2020, the index plunged down by 2919.26 points, the second–worst fall in the history, ending in red to a 33-month low at 32,778.14. The fall wiped off ₹11.2 lakh crores wealth ($160 billion). On Friday, 13 March, trading was halted for 45 minutes for the first time in 12 years since January 2008 due to lower circuit. Sensex touched a low of 29,687.52 down by 3090.62 points (or 9.43%). However, after the 45-minute halt, the index saw biggest intra-day recovery by 5,380 points to end up by 1325 points. Continuing the losing streak, wealth worth ₹14.22 lakh crore ($200 Billion) was erased on 23 March 2020 as BSE SENSEX lost 3,934.72 points to end at 25,981.24. As on 21 January 2021, Sensex has recovered to 50,167.71.
=== Oxygen carriers === Hemoglobin, which is the principal oxygen-carrier in humans, has four subunits in which the iron(II) ion is coordinated by the planar macrocyclic ligand protoporphyrin IX (PIX) and the imidazole nitrogen atom of a histidine residue. The sixth coordination site contains a water molecule or a dioxygen molecule. By contrast the protein myoglobin, found in muscle cells, has only one such unit. The active site is located in a hydrophobic pocket. This is important as without it the iron(II) would be irreversibly oxidized to iron(III). The equilibrium constant for the formation of HbO2 is such that oxygen is taken up or released depending on the partial pressure of oxygen in the lungs or in muscle. In hemoglobin the four subunits show a cooperativity effect that allows for easy oxygen transfer from hemoglobin to myoglobin. In both hemoglobin and myoglobin it is sometimes incorrectly stated that the oxygenated species contains iron(III). It is now known that the diamagnetic nature of these species is because the iron(II) atom is in the low-spin state. In oxyhemoglobin the iron atom is located in the plane of the porphyrin ring, but in the paramagnetic deoxyhemoglobin the iron atom lies above the plane of the ring. This change in spin state is a cooperative effect due to the higher crystal field splitting and smaller ionic radius of Fe2+ in the oxyhemoglobin moiety. Hemerythrin is another iron-containing oxygen carrier. The oxygen binding site is a binuclear iron center.
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。