Everything below concerns ESI-MS. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, a structure that differs from natural ghrelin in length and in the presence of non-natural amino acid residues. Early laboratory work described it as a comparatively selective agent that stimulates growth hormone release with limited effect on other pituitary hormones. The compound is supplied as a lyophilized solid for research use and has no identified natural source in the body.
现有文献多来自小规模、短期的研究，涉及生长激素缺乏、术后肠麻痹等方向。长期使用是否导致受体脱敏，以及重复给药后效应是否衰减，仍属开放问题。不同研究之间的剂量、给药途径和受试者特征差异较大，因此结论外推需谨慎。关于临床获益的确切证据尚不充分，需要更大规模的对照试验来澄清。
Ipamorelin 是一种合成五肽，在 20 世纪 90 年代被报道为生长激素促分泌剂。其结构基于胃饥饿素受体激动剂的设计思路，但并非天然激素。早期药理学研究显示，它可刺激垂体释放生长激素，而对应激激素轴的影响相对较小。该化合物常被用作研究生长激素调节通路的工具分子。
在机制层面，ipamorelin 与生长激素促分泌受体 1a 型结合，该受体也介导胃饥饿素的多种效应。受体激活后，细胞内信号促进生长激素从垂体前叶释放。由于对促肾上腺皮质激素和皮质醇的刺激较弱，它被视为选择性较高的促分泌剂。这种选择性在动物模型和少量人体研究中被观察到，但人体数据仍然有限。
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic pentapeptide | GHS-R1a agonist family |
| Receptor target | Ghrelin receptor (GHS-R1a) | G-protein-coupled receptor |
| Sequence length | Five amino acid residues | Includes non-natural residues |
| Primary reported output | Pulsatile growth hormone release | Observed in animal and early human work |
| Molecular formula | C38H49N9O5 | Corresponds to roughly 711.9 g/mol |
Verification of identity and purity relies on analytical methods used across peptide chemistry. Reverse-phase high-performance liquid chromatography separates components by hydrophobicity and provides a purity estimate. Mass spectrometry confirms molecular mass and helps detect modifications. Together these techniques give complementary information about whether a sample matches its expected structure. Results depend on method parameters and reference standards, so reported purity values are meaningful only when the analytical conditions are stated. Consistency between laboratories requires comparable protocols and well-characterized reference materials.
Peptides such as ipamorelin are subject to chemical and physical degradation. Hydrolysis of peptide bonds, oxidation of susceptible residues, and aggregation are common pathways that reduce purity over time. The rate of these processes depends on temperature, moisture, pH, and the number of freeze-thaw cycles a sample undergoes. Because the compound is typically handled as a lyophilized powder, controlling moisture during storage is a central concern. Degradation products can be detected with separation techniques that resolve the parent peptide from related impurities.
Human data remain limited and come mainly from small, short-term studies conducted decades ago. The peptide has not received approval as a medicine from major regulators, so current availability is largely as a research chemical. Reported effects on growth hormone pulsatility, appetite, and body composition should be read as preliminary, since few independent groups have replicated the original findings. Analytical characterization of research-grade material varies between suppliers, which complicates comparison across studies. Regulatory status also differs by country, and some jurisdictions classify it as a prescription-only or otherwise restricted item.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class. It acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. The compound was designed in the 1990s during a search for agents that release growth hormone with fewer off-target hormonal effects than earlier secretagogues. It appears in the research literature under several sequence-based names. Material supplied for laboratory work is normally a lyophilized solid, and it is not marketed as an approved therapeutic in major jurisdictions.
The molecule contains five residues, including alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, and it ends in a lysine amide. Non-natural and D-configured residues make the chain less susceptible to common peptidases, which helps explain its resistance to rapid breakdown. Its molecular formula is C38H49N9O5, corresponding to a free-base mass near 711.9 daltons. The C-terminal amide removes a negative charge and is a recurring feature in receptor-active peptides of this family. These structural choices are usually discussed as the basis for its selectivity profile.
Identity and purity assessment of ipamorelin relies mainly on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometers, a wavelength where the peptide backbone absorbs. Mass confirmation is typically obtained by electrospray ionization mass spectrometry or by liquid chromatography coupled to mass spectrometry, comparing the observed mass with the calculated value. Amino acid analysis and peptide mapping after enzymatic digestion can confirm the sequence. Impurity profiles include deletion peptides, truncated fragments, and oxidation products, reported as relative area percentages.
Lyophilized ipamorelin is generally held at minus twenty degrees Celsius or colder, protected from light and moisture. In solution the peptide is less stable, and degradation proceeds through hydrolysis of the amide backbone, oxidation of the histidine residue, and aggregation. Repeated freeze-thaw cycles accelerate these processes, so dividing material into single-use aliquots before freezing is common practice in research settings. Buffered formulations near neutral pH tend to show the slowest degradation, while strongly acidic or basic conditions raise hydrolysis rates. Stability data specific to ipamorelin are sparse, and much guidance is extrapolated from other short peptides.
==== Cancer immunotherapy ==== In 1995, Robert Conry demonstrated that intramuscular injection of naked RNA encoding carcinoembryonic antigen elicited antigen-specific antibody responses. Then, it was elaborated by demonstrating that dendritic cells(DCs) exposed to mRNA coding for specific antigens or to total mRNA extracted from tumor cells and injected into tumor-bearing mice induced T cell immune responses and inhibited the growth of tumors. Then, researchers started to approach mRNA transfected DCs using vaccines based on ex vivo IVT mRNA-transfected DCs. Meanwhile, Argos Therapeutics had initiated a Phase III clinical trial using DCs with advanced renal cell carcinoma in 2015 (NCT01582672) but it was terminated due to the lack of efficacy. For further application, IVT mRNA was optimized for in situ transfections of DCs in vivo. It improved the translation efficiency and stability of IVT mRNA and enhanced the presentation of the mRNA-encoded antigen on MHC class I and II molecules. Then, they found out that the direct injection of naked IVT mRNA into lymph nodes was the most effective way to induce T cell responses. Based on this discovery, first-in-human testing of the injection of naked IVT mRNA encoding cancer antigens by BioNTech has started with patients with melanoma (NCT01684241). Recently, the new cancer immunotherapy, the combining of self-delivering RNA(sd-rxRNA) and adoptive cell transfer(ACT) therapy, was invented by RXi Pharmaceuticals and the Karolinska Institute.
2 MoS2 + 7 O2 → 2 MoO3 + 4 SO2 The trioxide, which is volatile at high temperatures, is the precursor to virtually all other Mo compounds as well as alloys. Molybdenum has several oxidation states, the most stable being +4 and +6 (bolded in the table at left). Molybdenum(VI) oxide is soluble in strong alkaline water, forming molybdates (MoO42−). Molybdates are weaker oxidants than chromates. They tend to form structurally complex oxyanions by condensation at lower pH values, such as [Mo7O24]6− and [Mo8O26]4−. Polymolybdates can incorporate other ions, forming polyoxometalates. The dark-blue phosphorus-containing heteropolymolybdate P[Mo12O40]3− is used for the spectroscopic detection of phosphorus. The broad range of oxidation states of molybdenum is reflected in various molybdenum chlorides:
A transaminase converts the oxaloacetate to aspartate for transport back across the membrane and into the intermembrane space. In oxidative phosphorylation, the passage of electrons from NADH and FADH2 through the electron transport chain releases the energy to pump protons out of the mitochondrial matrix and into the intermembrane space. This pumping generates a proton motive force that is the net effect of a pH gradient and an electric potential gradient across the inner mitochondrial membrane. Flow of protons down this potential gradient – that is, from the intermembrane space to the matrix – yields ATP by ATP synthase. Three ATP are produced per turn. Although oxygen consumption appears fundamental for the maintenance of the proton motive force, in the event of oxygen shortage (hypoxia), intracellular acidosis (mediated by enhanced glycolytic rates and ATP hydrolysis), contributes to mitochondrial membrane potential and directly drives ATP synthesis. Most of the ATP synthesized in the mitochondria will be used for cellular processes in the cytosol; thus it must be exported from its site of synthesis in the mitochondrial matrix. ATP outward movement is favored by the inner mitochondrial membrane's electrochemical potential because the cytosol has a relatively positive charge compared to the relatively negative matrix. For every ATP transported out, it costs 1 H+. Producing one ATP costs about 3 H+. Therefore, making and exporting one ATP requires 4H+.
Between 1676 and 1689, Gottfried Leibniz first attempted a mathematical formulation of the kind of energy that is associated with motion (kinetic energy). Using Huygens's work on collision, Leibniz noticed that in many mechanical systems (of several masses mi, each with velocity vi),
==== Thermal decomposition of limestone ==== It is produced by thermal decomposition of limestone, CaCO3 by heating (calcining) at about 850 °C (1,560 °F), in the manufacture of quicklime (calcium oxide, CaO), a compound that has many industrial uses:
Sources: en.wikipedia.org
A unique identifier assigned by the investigator to each trial subject to protect the subject's identity and used in lieu of the subject's name when the investigator reports adverse events and/or other trial-related data. (ICH E6) Subject/Trial Subject
Castor oil is a vegetable oil pressed from castor beans, the seeds of the plant Ricinus communis. The seeds are 40 to 60 percent oil. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is 313 °C (595 °F) and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about 90 percent of fatty acids are ricinoleates. Oleic acid and linoleic acid are the other significant components. Some 270,000–360,000 tonnes (600×10^6–790×10^6 lb) of castor oil are produced annually for a variety of uses, including soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold-resistant plastics, waxes and polishes, nylon, and perfumes.
Patients with no history of red cell antibodies may qualify for computer-assisted crossmatch, which does not involve combining patient serum with donor cells. If an antibody is suspected, potential donor units must first be screened for the corresponding antigen by phenotyping them. Antigen negative units are then tested against the patient plasma using an antiglobulin/indirect crossmatch technique at 37 degrees Celsius to enhance reactivity and make the test easier to read. In urgent cases where crossmatching cannot be completed, and the risk of dropping hemoglobin outweighs the risk of transfusing uncrossmatched blood, O-negative blood is used, followed by crossmatch as soon as possible. O-negative is also used for children and women of childbearing age. It is preferable for the laboratory to obtain a pre-transfusion sample in these cases so a type and screen can be performed to determine the actual blood group of the patient and to check for alloantibodies.
cellular immunity Also cell-mediated immunity. A class of immune response that does not rely on the production of antibodies but rather the activation of specific cell types such as phagocytes or cytotoxic T-lymphocytes, or the secretion of various cytokines from cells, in response to an antigen.
Other democratic socialist parties in Asia include the National United Party of Afghanistan in Afghanistan, the April Fifth Action in Hong Kong, the All India Trinamool Congress, the Samajwadi Party, the Samta Party and the Sikkim Democratic Front in India, the Progressive Socialist Party in Lebanon, the Federal Socialist Forum and the Naya Shakti Party in Nepal, the Labor Party in South Korea and the Syrian Democratic People's Party and the Democratic Arab Socialist Union in Syria.
Sources: en.wikipedia.org
Medical genetics is concerned with the diagnosis and management of hereditary disorders. Neurology is concerned with diseases of the nervous system. In the UK, neurology is a subspecialty of general medicine. Obstetrics and gynecology (often abbreviated as OB/GYN (American English) or Obs & Gynae (British English)) are concerned respectively with childbirth and the female reproductive and associated organs. Reproductive medicine and fertility medicine are generally practiced by gynecological specialists. Pediatrics (AE) or paediatrics (BE) is devoted to the care of infants, children, and adolescents. Like internal medicine, there are many pediatric subspecialties for specific age ranges, organ systems, disease classes, and sites of care delivery. Pharmaceutical medicine is the medical scientific discipline concerned with the discovery, development, evaluation, registration, monitoring and medical aspects of marketing of medicines for the benefit of patients and public health. Physical medicine and rehabilitation (or physiatry) is concerned with functional improvement after injury, illness, or congenital disorders. Podiatric medicine is the study of, diagnosis, and medical and surgical treatment of disorders of the foot, ankle, lower limb, hip and lower back. Preventive medicine is the branch of medicine concerned with preventing disease. Community health or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis.
Geheimrat Julius Wilhelm Theodor Curtius (27 May 1857 – 8 February 1928) was professor of Chemistry at Heidelberg University. He published the Curtius rearrangement in 1890/1894 and also discovered diazoacetic acid, hydrazine and hydrazoic acid. In 1882 he carried out the first ever peptide synthesis, creating the N-protected dipeptide, benzoylglycylglycine.
=== Articular cartilage === Cartilage is an avascular, aneural and alymphatic tissue within the body. The extracellular matrix (ECM) of collagen is what gives it its high strength. The figure below shows the components of the ECM.
==== Distribution ==== The volume of distribution of propranolol is about 4 L/kg or 320 L. The plasma protein binding of propranolol is approximately 90%, with a range of 85 to 96% in different studies. Propranolol is a highly lipophilic drug achieving high concentrations in the brain. The brain-to-blood ratio of propranolol in humans ranges from 15:1 to 33:1, whereas the ratio for the peripherally selective beta blocker atenolol has been found to be 0.2:1.
Sources: en.wikipedia.org
It is a synthetic pentapeptide in the growth hormone secretagogue family and acts as an agonist at the ghrelin receptor. It is handled as a laboratory research compound rather than a naturally occurring hormone.
Studies generally report growth hormone as the dominant output, with smaller or absent effects on adrenocorticotropic hormone and prolactin. The size of that separation depends on the assay and the dose examined, so it is best described as relative selectivity.
No natural source has been identified, and the molecule is produced by chemical synthesis. Its non-natural residues distinguish it from endogenous ghrelin even though both engage the same receptor.
不是。它属于人工合成的五肽，设计上模拟胃饥饿素受体的部分作用，但不存在于人体天然激素谱中。