If you have been reading about electrospray ionisation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-19. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
Signal transduction begins when the peptide binds GHSR-1a on pituitary somatotrophs. The receptor couples to Gq/11 proteins, activating phospholipase C, which cleaves phosphatidylinositol bisphosphate into inositol trisphosphate and diacylglycerol. Inositol trisphosphate releases calcium from intracellular stores, and the resulting rise in cytosolic calcium drives growth hormone vesicle fusion. Concurrent Gs coupling and cyclic AMP elevation have also been reported, and the relative contribution of each arm to the overall secretory response is not fully settled.
Structural features distinguish the molecule from earlier secretagogues. An alpha-aminoisobutyric acid residue near the N-terminus and a D-naphthylalanine substitution increase receptor affinity, while C-terminal amidation improves resistance to exopeptidases. These modifications are associated with reduced stimulation of appetite and of the hypothalamic-pituitary-adrenal axis compared with hexarelin or growth hormone releasing peptide-6. Whether the same profile applies at every dose level studied is a matter of ongoing investigation rather than settled consensus.
Ipamorelin is a synthetic pentapeptide that acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. Its sequence incorporates non-natural residues, which slows enzymatic breakdown relative to short native peptides. In laboratory and early clinical work the compound is described as a selective growth hormone secretagogue because it raises growth hormone with comparatively little effect on other pituitary outputs. The degree to which that selectivity holds across species and dosing regimens remains an open question in the published literature.
| 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 |
Lyophilized material is generally held at minus twenty degrees Celsius or lower, protected from moisture and light. Repeated excursions to room temperature cause condensation inside the vial and gradual moisture uptake, both of which shorten shelf life. Containers should be allowed to equilibrate before opening so that water does not condense on the solid. Dividing a batch into single-use aliquots reduces freeze-thaw cycling. Solid peptide handled this way is usually considered stable for months to years, while the same material in solution degrades on a much shorter timescale.
Common solvents for laboratory work include water, buffered saline, and dimethyl sulfoxide. Once dissolved, the peptide is exposed to hydrolysis and oxidation, and alkaline conditions accelerate breakdown. Low-binding plasticware and the addition of a carrier protein reduce losses to container surfaces, which can otherwise be substantial at low concentrations. Solutions are typically kept cold and used within days. Investigators working with the compound generally prepare fresh working dilutions rather than storing dilute stocks, and they avoid repeated warming of the same vial.
Reversed-phase high-performance liquid chromatography is the standard method for purity assessment, most often on a C18 column with a water and acetonitrile gradient and trifluoroacetic acid or formic acid as an ion-pairing agent. Mass spectrometry by electrospray or matrix-assisted laser desorption confirms the expected mass and reveals truncated or modified sequences. Amino acid analysis and sequencing provide orthogonal structural evidence. Typical impurities include deletion sequences, oxidized products, and dimeric species. Detection wavelength, usually 214 or 220 nanometers, should be reported because response factors differ between peptides.
Mass spectrometry confirms identity and reveals structural deviations that chromatography alone can miss. Positive-mode electrospray ionisation generally yields multiply charged ions whose deconvoluted mass is checked against the theoretical value. Amino acid analysis, and enzymatic digestion with subsequent fragment mapping, provide independent confirmation of sequence and of the terminal amide. Analysts take care to separate the target from deletion sequences, which may differ by one residue and therefore by only a small mass increment.
The lyophilised solid is normally held at -20 °C or colder, shielded from light and moisture. Stability in that state is measured in years, although shelf life depends on residual water content and the container seal. Once dissolved, the peptide is more fragile: aqueous solutions are commonly kept at 2-8 °C and used within days to weeks, and repeated freeze-thaw cycling is avoided. Strongly acidic or basic conditions accelerate hydrolysis, and prolonged exposure to them can strip the terminal amide.
33. Eksp Klin Farmakol. 2006 Nov-Dec;69(6):13-6. [Comparative study of the effects of melatonin and epitalon on the protracted memory under the shuttle labyrinth test conditions in rats in the course of aging]. [Article in Russian] Vinogradova IA. The influence of the chronic administration of melatonin (epiphyseal hormone) and epitalon (a synthetic tetrapeptide increasing melatonin production) on the learning process and the protracted memory has been studied in LIO rats in the course of aging for 2 years under standard illumination regime (12L :12D). The daily administration of melatonin (Sigma, USA) with drinking water (in 10 mg/liter dose at night) in rats beginning with the age of 4 months did not influence the learning processes in young and adult animals but it was found to contribute to optimization of the brain cognitive function in rats in the course of aging, by improving the protracted memory process. Epitalon administered in a daily dose of 0.1 microg per animal beginning with the age of 4 months showed mnemotropic properties (decreasing the extent of memory disorders) in old rats under conditions of the shuttle labyrinth test.
8. Ir Med J. 2026 Sep 28;119(8):161. Type A Insulin Resistance Syndrome Due to a Pathogenic Variant in the INSR Gene. Afzal S, Brosnan E, Sadiq MS, Rizvi SR, Wassem Z, Iqbal F. PRESENTATION: A woman in her 40s initially diagnosed with type 1 diabetes in 1994 exhibited an atypical 30-year metabolic course, characterised by fluctuating insulin sensitivity, prolonged insulin independence and later insulin resistance despite a non-obese phenotype. DIAGNOSIS: Owing to the unusual clinical trajectory and a strong family history of young-onset diabetes, genetic testing identified a heterozygous pathogenic INSR mutation (p.M1180K), confirming Type A Insulin Resistance Syndrome (TAIRS). TREATMENT: Management evolved from insulin therapy to oral hypoglycaemic agents, including metformin and gliclazide alongside lifestyle modification resulting in partial glycaemic improvement. DISCUSSION: This case underscores the diagnostic challenge of TAIRS, which is frequently misclassified as type 1 or type 2 diabetes and highlights the importance of early genetic evaluation and multidisciplinary care.
== Occurrence == Rubidium is not abundant, being one of 56 elements that combined make up 0.05% of the Earth's crust; at roughly the 23rd most abundant element in the Earth's crust it is more abundant than zinc or copper. It occurs naturally in the minerals leucite, pollucite, carnallite, and zinnwaldite, which contain as much as 1% rubidium oxide. Lepidolite contains between 0.3% and 3.5% rubidium, and is the commercial source of the element. Some potassium minerals and potassium chlorides also contain the element in commercially significant quantities. Seawater contains an average of 125 μg/L of rubidium compared to the much higher value for potassium of 408 mg/L and the much lower value of 0.3 μg/L for caesium. Rubidium is the 18th most abundant element in seawater. Because of its large ionic radius, rubidium is one of the "incompatible elements". During magma crystallization, rubidium is concentrated together with its heavier analogue caesium in the liquid phase and crystallizes last. Therefore, the largest deposits of rubidium and caesium are zone pegmatite ore bodies formed by this enrichment process. Because rubidium substitutes for potassium in the crystallization of magma, the enrichment is far less effective than that of caesium. Zone pegmatite ore bodies containing mineable quantities of caesium as pollucite or the lithium minerals lepidolite are also a source for rubidium as a by-product.
Freeze-dried foods became a major component of astronaut and military rations. What began for astronaut crews as tubed meals and freeze-dried snacks that were difficult to rehydrate, were transformed into hot meals by improving the process of rehydrating freeze-dried meals with water. As technology and food processing improved, NASA looked for ways to provide a complete nutrient profile while reducing crumbs, disease-producing bacteria, and toxins. The crumb problem was solved with the addition of a gelatin coating on the foods to lock in and prevent crumbs. The complete nutrient profile was improved with the addition of an algae-based vegetable-like oil to add polyunsaturated fatty acids. Polyunsaturated fatty acids are beneficial in mental and vision development and, as they remain stable during space travel, can provide astronauts with added benefits. Disease-producing bacteria and toxins were reduced by quality control and the development of the Hazard Analysis and Critical Control Points (HACCP) plan, which is widely used today to evaluate food material before, during, and after processing. With the combination of these three innovations, NASA could provide safe and wholesome foods to their crews from freeze-dried meals. Military rations have also come a long way, from being served cured pork and corn meal to beefsteaks with mushroom gravy. How rations are chosen and developed is based on acceptance, nutrition, wholesomeness, producibility, cost, and sanitation.
Sources: pubmed.ncbi.nlm.nih.gov
United States Policies targeting Muslims: Since the implementation of added security measures in the aftermath of the 2001 World Trade Centre attacks, reports of discrimination against people perceived to be Muslim by American border security officers have been prevalent in the media. The travel restrictions implemented during the Trump presidency primarily against Muslim majority countries have provoked controversy over whether such measures are a legitimate Border security measure or unethically discriminatory. Separation of families seeking asylum: In April 2018, as part of its "zero tolerance" policy, the American government ordered the separation of the children of refugees and asylum seekers from their parents. As a consequence of popular outrage, and criticism from the medical and religious communities, the policy was put on hold by an executive order signed by Trump on 20 June 2018. Under the policy, federal authorities separated children from their parents, relatives, or other adults who accompanied them in crossing the border, whether apprehended during an illegal crossing or, in numerous reported cases, legally presenting themselves for asylum. The policy involved prosecuting all adults detained at the Mexican border, imprisoning parents, and handing minors to the American Department of Health and Human Services (Spanish: Departamento de Salud y Servicios Sociales de los Estados Unidos). The federal government reported that the policy resulted in the separation of over 2300 children from their parents.
polymer A macromolecule composed of multiple repeating subunits or monomers; a chain or aggregation of many individual molecules of the same compound or class of compound. The formation of polymers is known as polymerization and generally only occurs when nucleation sites are present and the concentration of monomers is sufficiently high. Many of the major classes of biomolecules are polymers, including nucleic acids and polypeptides.
Dorothy Mary Crowfoot Hodgkin (née Crowfoot; 12 May 1910 – 29 July 1994) was an English chemist who advanced the technique of X-ray crystallography to determine the structure of biomolecules, which became essential for structural biology. She received the 1964 Nobel Prize in Chemistry, and is the only British woman scientist to have been awarded a Nobel Prize. Among her most influential discoveries are the confirmation of the structure of penicillin as previously surmised by Edward Abraham and Ernst Boris Chain; and mapping the structure of vitamin B12, for which in 1964 she became the third woman to win the Nobel Prize in Chemistry. Hodgkin also elucidated the structure of insulin in 1969 after 35 years of work. Hodgkin used the name "Dorothy Crowfoot" until twelve years after marrying Thomas Lionel Hodgkin, when she began using "Dorothy Crowfoot Hodgkin". Hodgkin is referred to as "Dorothy Hodgkin" by the Royal Society (when referring to its sponsorship of the Dorothy Hodgkin fellowship), and by Somerville College. The National Archives of the United Kingdom refer to her as "Dorothy Mary Crowfoot Hodgkin". The case of her Nobel prize is inscribed 'Crowfoot Hodgkin'.
== Early life and education == Sur did his early schooling at the St. Joseph's Collegiate School, Allahabad. He received a Bachelor of Technology degree in electrical engineering from the Indian Institute of Technology in Kanpur (IIT Kanpur) in 1974, and Master of Science and PhD degrees in electrical engineering in 1975 and 1978, respectively, from Vanderbilt University in Nashville. After postdoctoral research at Stony Brook University, he was appointed to the faculty of Yale University School of Medicine in 1983.
== Function == This gene encodes a transmembrane transporter that likely plays a role in monocarboxylic acid transport. A mutation in this gene has been associated with juvenile cataracts with microcornea and renal glucosuria. [provided by RefSeq, Mar 2010].
Sources: en.wikipedia.org
Sunflower, corn, and soybean oil have a higher proportion of omega-6 fatty acids than oils from fish, walnuts, flaxseed, and rapeseed (canola). Omega-6 fatty acids constitute a growing proportion of Americans' fat intake. They have been hypothesized to contribute to several negative health effects, including inflammation and immunodeficiency, but most cardiovascular health researchers believe the data shows that omega-6 fatty acids are safe and healthy for humans. In fact, omega-6 fatty acids are significantly associated with a lowered risk of cardiovascular disease, and the American Heart Association has stated that a reduction in omega-6 fatty acids could lead to an increase, not reduction, in cardiovascular disease. Research indicates that consumption of omega-6 fatty acids has no significant effect on inflammatory bowel disease.
==== Pelvic floor physical therapy ==== Pelvic floor physical therapy (pelvic floor physiotherapy / rehabilitation) may involve training of individual pelvic floor muscles, biofeedback, rectal balloon exercises, transcutaneous nerve stimulation or percutaneous tibial nerve stimulation. Rehabilitation program is personalized according to the symptoms. Patients with IRP fall into three groups: those with fecal incontinence, those with obstructed defecation, and those with both. In those with incontinence, there may be low resting pressure, low maximal squeeze pressure in the anal canal, and disordered rectal sensation or reduced rectal compliance. Treatment measures may include volumetric rehabilitation, electrostimulation, biofeedback, and pelviperineal kinesitherapy. There is improvement in incontinence in 68% of cases, and complete improvement in symptoms in 31% of cases. In those with obstructed defecation, there is usually pelvic floor dyssynergia or descending perineum syndrome. This may be treated with "bimodal rehabilitation", which is combined pelviperineal kinesitherapy and biofeedback training. The former is a muscular re-education method directed at the levator ani, especially puborectalis. It improves extension, elasticity, and performance of the muscle. In one study, patients with IRP underwent biofeedback retraining. 33% reported complete resolution of constipation, 19% partial improvement, and 48% had no improvement.
=== Contamination === Any addition of carbon to a sample of a different age will cause the measured date to be inaccurate. Contamination with modern carbon causes a sample to appear to be younger than it really is: the effect is greater for older samples. If a sample that is 17,000 years old is contaminated so that 1% of the sample is modern carbon, it will appear to be 600 years younger; for a sample that is 34,000 years old, the same amount of contamination would cause an error of 4,000 years. Contamination with old carbon, with no remaining 14C, causes an error in the other direction independent of age – a sample contaminated with 1% old carbon will appear to be about 80 years older than it truly is, regardless of the date of the sample.
=== Comprehensive Drug Abuse and Control Act === The original act, passed in 1970, allowed governments to attain funds, drugs, and equipment seized during raids through civil court hearings and drug convictions. Over the years, the list of items allowed to be seized grew in size. In 1984, the Act was amended to allow federal law enforcement agencies to "retain and use any and all proceeds from asset forfeitures, and to allow state and local police agencies to retain up to 80 percent of the assets value." The law now allowed police units to seize cars, cash, and property from drug raids, even without a conviction. "Because those who were targeted were typically poor or of moderate means, they often lacked resources to hire an attorney or pay the considerable court costs. As a result, most people who had their property seized did not challenge the government's action, especially because the government could retaliate by filing criminal charges." Between 1989 and 1992, federally funded state and local police agencies seized over $1 billion in assets. That did not include the DEA or other federally funded enforcement agencies.
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。