This is a working overview of pentapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
Identity and purity assessment for a research peptide of this kind typically combines reversed-phase high-performance liquid chromatography with mass spectrometry. The chromatographic run separates related impurities and yields a purity percentage, while electrospray ionization or matrix-assisted laser desorption mass spectrometry confirms the expected molecular mass. Amino acid analysis or tandem mass spectrometry sequencing can add confidence when material is intended for quantitative work. Laboratories differ in how they calculate and report purity, so figures from different sources are not always directly comparable.
Lyophilized material is generally stored cold and dry, with desiccant, and protected from light. In solution the peptide is more vulnerable: the histidine side chain can oxidize, and repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. A mildly acidic aqueous buffer is often used for short-term handling because it limits several degradation routes. Accurate prediction of long-term stability under a given set of conditions is difficult, and published stability data remain sparse.
Published discussion of this compound is uneven. Some references describe it as a tool for probing growth hormone regulation, while others focus on analytical characterization or on comparisons with related secretagogues. Statements about selectivity, half-life and potency often trace back to a small number of original reports that later authors cite secondhand. Readers evaluating a claim should therefore check whether a figure reflects a direct measurement or a repeated citation, and whether the underlying study was conducted in animals, in isolated cells or in human volunteers.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid as supplied |
| Solubility | Freely soluble in water and polar solvents | Dissolution may require brief mixing |
| Typical storage temperature | Minus 20 degrees Celsius or below | Dry, desiccated, protected from light |
| Common analytical method | Reversed-phase HPLC with mass spectrometry | Purity plus identity confirmation |
| Common synonyms | Ipamorelin acetate, NNC 26-0161 | Research code used in early literature |
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.
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.
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.
The two substrates of this enzyme are sequoyitol and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 2D-5-O-methyl-2,3,5/4,6-pentahydroxycyclohexanone, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 5-O-methyl-myo-inositol:NAD+ oxidoreductase. This enzyme is also called D-pinitol dehydrogenase.
The observation of such magnetic resonance frequencies of the nuclei present in a molecule makes it possible to determine essential chemical and structural information about the molecule. The improvements of the NMR method benefited from the development of electromagnetic technology and advanced electronics and their introduction into civilian use. Originally as a research tool it was limited primarily to dynamic nuclear polarization, by the work of Anatole Abragam and Albert Overhauser, and to condensed matter physics, where it produced one of the first demonstrations of the validity of the BCS theory of superconductivity by the observation by Charles Slichter of the Hebel-Slichter effect. It soon showed its potential in organic chemistry, where NMR has become indispensable, and by the 1990s improvement in the sensitivity and resolution of NMR spectroscopy resulted in its broad use in analytical chemistry, biochemistry and materials science. In the 2020s zero- to ultralow-field nuclear magnetic resonance (ZULF NMR), a form of spectroscopy that provides abundant analytical results without the need for large magnetic fields, was developed. It is combined with a special technique that makes it possible to hyperpolarize atomic nuclei.
This molecule is then reduced to mevalonate by the enzyme HMG-CoA reductase. Production of mevalonate is the rate-limiting and irreversible step in cholesterol synthesis and is the site of action for statins (a class of cholesterol-lowering drugs).
Sources: en.wikipedia.org
Play Australian rules football at any level; Enter the club premises or clubrooms on game day; Train under the direction of a club-devised program; or Return to their clubs' training sessions until two months before their bans expired. Because of these limitations, the bans also covered most forms of coaching. As such, two former players (Mark McVeigh and Henry Slattery) who were employed as non-playing coaches were suspended from their jobs, and players serving as playing coaches in country leagues were suspended from performing either function. The bans extended to any sport administered by a signatory to the WADA code, precluding active involvement in almost any organised sport during 2016. Players were not completely banned from involvement with the AFL, and were permitted to:
=== Nuclear medicine === Theranostics originated in the field of nuclear medicine; iodine isotope 131 for the diagnostic study and treatment of thyroid cancer was one of its earliest applications. Nuclear medicine encompasses various substances, either alone or in combination, that can be used for diagnostic imaging and targeted therapy. These substances may include ligands of receptors present on the target tissue or compounds, like iodine, that are internalized by the target through metabolic processes. By using these mechanisms, theranostics enables the localization of pathological tissues with imaging and the targeted destruction of these tissues using high doses of radiation.
Polystyrene Composition – The University of Southern Mississippi SPI resin identification code – Society of the Plastics Industry Polystyrene: Local Ordinances – Californians Against Waste Take a Closer Look at Today's Polystyrene Packaging (brochure by the industry group American Chemistry Council, arguing that the material is "safe, affordable and environmentally responsible") Lettieri TR, Hartman AW, Hembree GG, Marx E (1991). "Certification of SRM1960: Nominal 10 μm Diameter Polystyrene Spheres ("Space Beads")". Journal of Research of the National Institute of Standards and Technology. 96 (6): 669–691. doi:10.6028/jres.096.044. PMC 4915770. PMID 28184141.
Sources: en.wikipedia.org
Reversed-phase liquid chromatography is standard for purity, and mass spectrometry is standard for identity. Amino acid analysis is used when quantitative composition matters. No single technique answers every question, so laboratories usually combine two or three.
The peptide contains aromatic and imidazole groups that absorb ultraviolet light and can participate in photo-induced reactions. Those reactions can alter the molecule or generate new species. Amber glass or opaque packaging reduces the exposure.
Long-term stability data across many temperature and humidity conditions are limited. Most guidance is extrapolated from short studies on related peptides. The effect of repeated handling on a specific lot is generally not characterized.
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。