GHS-R1a raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-04-28 and is reviewed periodically as new material appears.
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.
| 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 |
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.
Purity is normally reported as a percentage of total peak area, a figure that does not account for water content, residual solvents, or counterions. Trifluoroacetate and acetate are the most frequent counterions in lyophilized peptides, and they shift the true peptide content away from the mass of the powder. A separate quantitative assay is therefore needed to state content accurately. Certificates of analysis often omit these details, which makes batch-to-batch comparison difficult and limits conclusions drawn when results from different suppliers are compared.
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.
Purity assessment for this peptide relies mainly on reversed-phase high-performance liquid chromatography. A C18 column with a water-acetonitrile gradient containing trifluoroacetic acid separates the target from truncated sequences and oxidation products. Detection near 214 nm exploits the amide backbone, while the aromatic side chains allow additional monitoring close to 280 nm. Reported purity values depend on the method, so a certificate of analysis carries weight only when gradient, column and integration parameters are given.
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.
Activity is mediated mainly through the growth hormone secretagogue receptor, now generally called the ghrelin receptor or GHS-R1a. Binding at this G-protein-coupled receptor triggers phospholipase C signaling, calcium mobilization, and release of growth hormone from pituitary somatotrophs. Reports describe less pronounced stimulation of adrenocorticotropic hormone and prolactin compared with earlier secretagogues such as hexarelin or GHRP-6. Selectivity figures vary between assay systems, so the degree of separation from other secretagogues is an area of ongoing comparison rather than a fixed constant.
In animal and early human studies, ipamorelin produces pulsatile growth hormone release and a secondary rise in insulin-like growth factor 1. The magnitude and duration of that rise depend on route, sampling schedule, and the baseline endocrine state of the subject. Whether repeated exposure alters the response over time is not firmly settled, since some reports describe stable pulsatility while others note attenuation. Most published data come from small samples, which limits the strength of any general claim about long-term behavior.
L'Origine du monde (Origin of the World), painted by Gustave Courbet in 1866, was an early Realist painting of a vulva that only became exhibited many years later. The painting was commissioned by Ottoman diplomat Halil Şerif Paşa. The woman used as the model for the painting was probably Halil's lover Constance Quéniaux. However, another potential model is Marie-Anne Detourbay, who was also a lover of Halil Şerif Pasha. Japanese sculptor and manga artist Megumi Igarashi has focused much of her work on painting and modelling vulvas and vulva-themed works. She has used molds to create dioramas – three-dimensional models of her vulva with the hope of demystifying the female genitals. An art installation called The Dinner Party by feminist artist, Judy Chicago, portrays a symbolic history of famous women. The dinner plates each depict an elaborate vulval form and they are arranged in a triangular vulva shape. Another installation was made by British artist Jamie McCartney who used the casts of four hundred vulvas to create The Great Wall of Vagina in 2011. The casts are life-size. Explanations written by the project's sexual health adviser accompany these. The purpose of the artist was to "address some of the stigmas and misconceptions that are commonplace".
== Diagnosis == While Sjögren's disease is one of the most common autoimmune diseases, it has no specific and non-invasive diagnostic tests. Diagnosing Sjögren's disease is complicated by the range of symptoms that a patient may manifest, and the similarity between symptoms of Sjögren's disease and those of other conditions. Also, patients with Sjögren’s symptoms approach different specialities for treatment, which can make diagnosis difficult. Since dry eyes and dry mouth are very common symptoms, and frequently occur in people over 40, affected people may believe the symptoms are age-related. Therefore, they often ignore them. Some medications can cause symptoms similar to those of Sjögren's disease.
=== Biological slug mucus === Mucus from gastropods is composed of a combination of water and glycoproteins, enzymes, and trace amounts of metal ions. Mucin glycoproteins, like achacin and glycosaminoglycans (GAGs) like hyaluronic acid are the primary components of mucus, contributing to its antimicrobial properties. Amino groups interact with the sulfate and carboxyl groups found in the glycosaminoglycans to promote bonding and hydrophobic interactions during gel formations. Other molecules like allantoin, or 5-ureidohyantoin, can be found in slug mucus to prompt cell proliferation and wound healing, as well as collagen synthesis, respectively. Significant amounts of zinc, iron, copper, and manganese metal ions are typically found in the chemical composition of slug mucus.
=== miRNA === Micro RNAs (miRNAs) are short, ~19-23 base pair long RNA oligonucleotides that are involved in the microRNA-induced silencing complex. Specifically, once loaded onto the ARGONAUTE enzyme, miRNAs work with mRNAs to repress translation and post-translationally destabilize mRNA. While they are functionally similar to siRNAs, miRNAs do not require extensive base-pairing for mRNA silencing (can require as few as seven base-pairs with target), thus allowing them to broadly affect a wider range of mRNA targets. In the cell, miRNA uses switch, tuning, and neutral interactions to finely regulate gene repression. As a therapeutic, miRNA has the potential to affect biochemical pathways throughout the organism. With more than 400 miRNA identified in humans, discerning their target gene for repression is the first challenge. Multiple databases have been built, for example TargetScan, using miRNA seed matching. In vitro assays assist in determining the phenotypic effects of miRNAs, but due to the complex nature of gene regulation not all identified miRNAs have the expected effect. Additionally, several miRNAs have been found to act as either tumor suppressors or oncogenes in vivo, such as the oncogenic miR-155 and miR-17-92. In clinical trials, miRNA are commonly used as biomarkers for a variety of diseases, potentially providing earlier diagnosis as well as disease progression, stage, and genetic links. Phase 1 and 2 trials currently test miRNA mimics (to express genes) and miRNA (to repress genes) in patients with cancers and other diseases.
Sources: en.wikipedia.org
Sherman leaves with Richmond and a tennis ball covered in the youth formula and heads to a presentation at Phleer Pharmaceuticals that Buddy is giving about the youth formula. Meanwhile, a worried Denise discovers what has happened and that Sherman's brain damage is progressing. With Cletus' help, Denise goes after him. Sherman takes advantage of the canine DNA crossed with Buddy's and throws the tennis ball to distract him. Buddy catches the ball in his mouth, and the youth formula transforms him back into a toddler, then further into a glowing mass of sentient genetic material. Sherman chases the genetic material, intent on drinking it to correct his condition. However, the material evaporates on the edge of a fountain before he can get to it. Cletus and Denise arrive too late to save him, and Denise breaks into tears, which hit the genetic material and fall into the fountain. As they go to leave, Sherman looks into the fountain, remarking that it is "pretty". Seeing the water is glowing, Denise realizes the genetic material has reconstituted thanks to her tears and that if Sherman drinks the fountain water before it dissipates, he will be restored to normal. Sherman drinks the water and is able to restore his genetic makeup to its proper order, restoring his intelligence. With Buddy Love defeated, Sherman and Denise finally get married. During the wedding reception, Sherman's older brother, Ernie Klump Sr., sings a song in honor of the couple, while Richmond continues to be hexed by the now normal-sized hamster.
Effects of ROS on cell metabolism are well documented in a variety of species. These include not only roles in apoptosis (programmed cell death) but also positive effects such as the induction of host defence genes and mobilization of ion transporters. This implicates them in control of cellular function. In particular, platelets involved in wound repair and blood homeostasis release ROS to recruit additional platelets to sites of injury. These also provide a link to the adaptive immune system via the recruitment of leukocytes. Reactive oxygen species are implicated in cellular activity to a variety of inflammatory responses including cardiovascular disease. They may also be involved in hearing impairment via cochlear damage induced by elevated sound levels, in ototoxicity of drugs such as cisplatin, and in congenital deafness in both animals and humans. ROS are also implicated in mediation of apoptosis or programmed cell death and ischaemic injury. Specific examples include stroke and heart attack. In general, the harmful effects of reactive oxygen species on the cell are the damage of DNA or RNA, oxidation of polyunsaturated fatty acids in lipids (lipid peroxidation), oxidation of amino acids in proteins, and oxidative deactivation of specific enzymes by oxidation co-factors. They play a role in causing dangerous genetic mutations.
== History == The existence of tRNA was first hypothesized by Francis Crick as the "adaptor hypothesis" based on the assumption that there must exist an adapter molecule capable of mediating the translation of the RNA alphabet into the protein alphabet. Paul C Zamecnik, Mahlon Hoagland, and Mary Louise Stephenson discovered tRNA in 1958. Significant research on structure was conducted in the early 1960s by Alex Rich and Donald Caspar, two researchers in Boston, the Jacques Fresco group in Princeton University and a United Kingdom group at King's College London. In 1965, Robert W. Holley of Cornell University reported the primary structure and suggested three secondary structures. tRNA was first crystallized in Madison, Wisconsin, by Robert M. Bock. The cloverleaf structure was ascertained by several other studies in the following years and was finally confirmed using X-ray crystallography studies in 1974. Two independent groups, Kim Sung-Hou working under Alexander Rich and a British group headed by Aaron Klug, published the same crystallography findings within a year.
Sources: en.wikipedia.org
== Selected publications == Bence, Kendra K.; Delibegovic, Mirela; Xue, Bingzhong; Gorgun, Cem Z.; Hotamisligil, Gokhan S.; Neel, Benjamin G.; Kahn, Barbara B. (2006). "Neuronal PTP1B regulates body weight, adiposity and leptin action". Nature Medicine. 12 (8): 917–924. doi:10.1038/nm1435. ISSN 1546-170X. PMID 16845389. S2CID 10654045. Delibegovic, Mirela; Zimmer, Derek; Kauffman, Caitlin; Rak, Kimberly; Hong, Eun-Gyoung; Cho, You-Ree; Kim, Jason K.; Kahn, Barbara B.; Neel, Benjamin G.; Bence, Kendra K. (2009-03-01). "Liver-Specific Deletion of Protein-Tyrosine Phosphatase 1B (PTP1B) Improves Metabolic Syndrome and Attenuates Diet-Induced Endoplasmic Reticulum Stress". Diabetes. 58 (3): 590–599. doi:10.2337/db08-0913. ISSN 0012-1797. PMC 2646057. PMID 19074988. Delibegovic, Mirela; Bence, Kendra K.; Mody, Nimesh; Hong, Eun-Gyoung; Ko, Hwi Jin; Kim, Jason K.; Kahn, Barbara B.; Neel, Benjamin G. (2007-11-01). "Improved Glucose Homeostasis in Mice with Muscle-Specific Deletion of Protein-Tyrosine Phosphatase 1B". Molecular and Cellular Biology. 27 (21): 7727–7734. doi:10.1128/MCB.00959-07. ISSN 0270-7306. PMC 2169063. PMID 17724080.
=== 1979 === 5 August: Alison Chambers (16). Chambers had been placed into foster care at the age of 14 and had repeatedly absconded from Jordan's Brook House. She became acquainted with the Wests in mid-1979, and Fred later claimed to his solicitor that Chambers had died as a result of Rose becoming "too bloody vicious" with her. Her dismembered body, missing several bones and with a leather belt looped beneath her jaw and tied at the top of her head, was buried in the garden of Cromwell Street. This was the final murder where a definite sexual motive was established.
Prostaglandin H2 (PGH2), or prostaglandin H2 (PGH2), is a type of prostaglandin and a precursor for many other biologically significant molecules. It is synthesized from arachidonic acid in a reaction catalyzed by a cyclooxygenase enzyme. The conversion from arachidonic acid to prostaglandin H2 is a two-step process. First, COX-1 catalyzes the addition of two free oxygens to form the 1,2-dioxane bridge and a peroxide functional group to form prostaglandin G2 (PGG2). Second, COX-2 reduces the peroxide functional group to a secondary alcohol, forming prostaglandin H2. Other peroxidases like hydroquinone have been observed to reduce PGG2 to PGH2. PGH2 is unstable at room temperature, with a half life of 90–100 seconds, so it is often converted into a different prostaglandin. PGH2 is produced by every type of cell except for red blood cells and has a wide range of effects in the body.
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。