Everything below concerns 非天然氨基酸. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-22. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
In the scientific literature, ipamorelin appears mainly in preclinical studies, receptor binding assays, and reviews of growth hormone secretagogues. Authors often discuss its selectivity profile alongside limitations such as small sample sizes, short study durations, and differences between species. Some papers examine pharmacokinetics and clearance, but human data are limited and not sufficient to define general clinical effects. Regulatory discussion treats the compound as an investigational or research substance rather than an approved therapy in most jurisdictions. Open questions include oral bioavailability, long-term endocrine effects, and whether selectivity observed in animals persists in humans.
Research peptides such as ipamorelin are commonly supplied as lyophilized powder and characterized by analytical certificates. Reversed-phase high-performance liquid chromatography is used to estimate purity by ultraviolet absorbance, while mass spectrometry confirms molecular identity and detects sequence-related impurities. Counterion content, water content, and residual synthesis reagents can affect the reported mass balance. A certificate of analysis may list a purity percentage, but that number depends on the analytical method and the definition of impurity peaks. Independent verification is often recommended because research supply chains vary in quality control practices.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic pentapeptide | Growth hormone secretagogue family |
| Molecular mass | Approximately 711.9 Da | Free base, calculated value |
| Receptor target | GHS-R1a, the ghrelin receptor | Agonist activity reported |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 | C-terminal amide |
| Reported selectivity | Little change in ACTH, cortisol, prolactin | Based mainly on animal data |
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor type 1a, the same G protein-coupled receptor that binds ghrelin. Receptor activation couples to Gq/11 signaling, raising intracellular calcium through inositol trisphosphate and diacylglycerol, which in turn promotes exocytosis of growth hormone from pituitary somatotroph cells. Ipamorelin binds this receptor with high affinity and shows weak activity at other secretagogue-related targets in vitro. Its action requires the intact receptor and is not reversed by growth hormone-releasing hormone antagonists.
Compared with earlier growth hormone secretagogues such as GHRP-6 and hexarelin, ipamorelin has been reported to produce less stimulation of adrenocorticotropic hormone, cortisol, and prolactin in animal and early human studies. This selectivity is usually attributed to differences in receptor subtype interactions and to the tissue distribution of the receptor. Effects on appetite appear weaker than those of ghrelin itself, although the supporting evidence base is small. Whether these differences produce a distinct clinical profile remains an open question, since controlled human trials are limited.
Ipamorelin is a synthetic pentapeptide first described in the 1990s by researchers at Novo Nordisk during a program to develop selective growth hormone secretagogues. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, incorporating two non-natural residues, alpha-aminoisobutyric acid and D-2-naphthylalanine. The C-terminus is amidated, and the material is supplied as a white lyophilized powder. The molecular formula is C38H49N9O5 and the monoisotopic mass is approximately 711.85 daltons. The short chain and modified residues give it greater resistance to enzymatic degradation than many larger peptide hormones.
Published animal and early human work describes growth hormone release that is separated from comparable rises in adrenocorticotropic hormone and cortisol. Prolactin changes are reported as small in the same studies. Selectivity is attributed to binding at the ghrelin receptor and to the downstream signaling that follows, rather than to differences in how quickly the peptide is cleared. Authors commonly label the compound selective rather than potent, because the same mass produces a smaller growth hormone response than some older secretagogues tested in parallel. Whether that profile holds across species and routes of administration remains an open question.
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 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。
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.
Selectivity is the property most often attached to this peptide. Published animal and early human studies record increases in growth hormone release after administration, with adrenocorticotropic hormone and cortisol responses remaining small by comparison. Effects on appetite-related pathways also appear weaker than those reported for several earlier secretagogues. Reviews that compare members of the growth hormone secretagogue family cite these findings frequently, though the receptor-level explanation for the selectivity continues to be debated rather than settled.
It was thought appropriate to choose a name to dissociate nicotinic acid from nicotine, to avoid the perception that vitamins or niacin-rich food contains nicotine, or that cigarettes contain vitamins. The resulting name niacin was derived from nicotinic acid + vitamin. Carpenter found in 1951, that niacin in corn is biologically unavailable, and can be released only in very alkaline lime water of pH 11. This explains why a Latin-American culture that used alkali-treated cornmeal to make tortilla was not at risk for niacin deficiency. The modern explanation is that alkali treatment enhances the bioavailability of tryptophan, not directly for any form of the vitamin. In 1955, Altschul and colleagues described large amounts of nicotinic acid as having a lipid-lowering property. As such, niacin is the oldest known lipid-lowering drug. Lovastatin, the first 'statin' drug, was first marketed in 1987.
The inorganic carbon species include carbon dioxide, carbonic acid, bicarbonate anion, and carbonate. It is customary to express carbon dioxide and carbonic acid simultaneously as CO2*. CT is a key parameter when making measurements related to the pH of natural aqueous systems, and carbon dioxide flux estimates.
== Etymology == Naja christyi was first described by Belgian-British zoologist George Albert Boulenger in 1904. The generic name Naja is a Latinisation of the Sanskrit word nāgá (नाग) meaning "cobra". The specific epithet, christyi, is in honor of Dr. Cuthbert Christy, who led several biological expeditions to the Democratic Republic of the Congo.
=== In eukaryotes === As with any protein or RNA, rRNA production is prone to errors resulting in the production of non-functional rRNA. To correct this, the cell allows for degradation of rRNA through the non-functional rRNA decay (NRD) pathway. Much of the research in this topic was conducted on eukaryotic cells, specifically Saccharomyces cerevisiae yeast. Currently, only a basic understanding of how cells are able to target functionally defective ribosomes for ubiquination and degradation in eukaryotes is available.
At the isoelectric point (pI), the total charge on the protein is 0 and it will not bind to the matrix. If the pH is above the pI, the protein will have a negative charge and bind to the matrix in an anion exchange column. The stability of the protein at values above or below the pI, will determine if an anion exchange column or cation exchange column should be used. If it is stable at pH values below the pI, the cation exchange column can be used. If it is stable at pH values above the pI then the anion exchange column can be used.
Sources: en.wikipedia.org
More Than Real, who won the prestigious 2010 Breeders' Cup Juvenile Fillies Turf; Creator (part owner), who won the third jewel of the Triple Crown, the Belmont Stakes in 2016; and Pizza Bianca, a homebred filly who won the 2021 Breeders' Cup Juvenile Fillies Turf. Flay served on the Breeders' Cup board of directors from 2014 to 2018.
By studying the ratio between two isotopes of the same element, we avoid effects involving the overall abundance of the element, which usually swamp the much smaller variations in isotopic abundances. Isotopic tracers are some of the most important tools in geology because they can be used to understand complex mixing processes in earth systems. Further discussion of the application of isotopic tracers in geology is covered under the heading of isotope geochemistry. Isotopic tracers are usually subdivided into two categories: stable isotope tracers and radiogenic isotope tracers. Stable isotope tracers involve only non-radiogenic isotopes and usually are mass-dependent. In theory, any element with two stable isotopes can be used as an isotopic tracer. However, the most commonly used stable isotope tracers involve relatively light isotopes, which readily undergo fractionation in natural systems. See also isotopic signature. A radiogenic isotope tracer involves an isotope produced by radioactive decay, which is usually in a ratio with a non-radiogenic isotope (whose abundance in the earth does not vary due to radioactive decay).
Qing authorities established the Canton System in 1757 to regulate trade more strictly, restricting non-Russian ships to the port of Canton. Although European demand for Chinese commodities like tea, silk, and porcelain was high, Chinese interest in European manufactured goods was insignificant, so that Chinese goods could only be bought with precious metals. To reduce the trade imbalance, the British sold large amounts of Indian opium to China. Faced with a drug crisis, Qing officials pursued ever more aggressive actions to halt the opium trade.
Acetylpropionylmorphine is an opioid analog that is an ester of morphine. It was developed in the early 1900s after first being synthesized in United Kingdom in 1875 but shelved along with heroin and various other esters of morphine. Acetylpropionylmorphone was never used medically, instead being widely sold as one of the first "designer drugs" for around five years following the introduction of the first international restrictions on the sale of heroin in 1925. It is described as being virtually identical to heroin and morphine in its effects, and consequently was itself banned internationally in 1930 by the Health Committee of the League of Nations, in order to prevent its sale as an unscheduled alternative to heroin.
Sources: en.wikipedia.org
Plant hormones (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book. Phytohormones occur across the plant kingdom, and even in algae, where they have similar functions to those seen in vascular plants ("higher plants"). Some phytohormones also occur in microorganisms, such as unicellular fungi and bacteria, however in these cases they do not play a hormonal role and can better be regarded as secondary metabolites.
=== Electrical === In electrical FFF a transverse electrical current (DC) is applied which creates an electric field. Depending on the charge of sample components, an electrophoretic drift velocity is induced, counteracted by the diffusion from Brownian motion, so the separation depends on the ratio of electrophoretic mobility and size. Application of electrical FFF has been limited and is currently rarely used. Other modifications have been developed, namely cyclical electrical FFF where a special alternating current is applied. It allows to separate according to electrophoretic mobility. Another variation is electrical asymmetrical flow FFF (EAF4), where an electrical field is applied in addition to a cross flow field. EAF4 overcomes the limitation of pure electrical FFF which has poor resolution and suffers from electrolysis products and bubbles contaminating the channel outflow and compromising the detector signals.
Flaps may include skin in their construction. Skin is important for many reasons, but its role in thermoregulation, immune function, and blood supply aid in flap survival. The skin can be divided into three main layers: the epidermis, dermis, and subcutaneous tissue. Blood is mainly supplied to the skin by two networks of blood vessels. The deep network lies between the dermis and the subcutaneous tissue, while the shallow network lies within the papillary layer of the dermis. The epidermis is supplied by diffusion from this shallow network and both networks are supplied by collaterals, and by perforating arteries that bring blood from deeper layers either between muscles (septocutaneous perforators) or through muscles (musculocutaneous perforators). This robust and redundant blood supply is important in flap surgery, because flaps are cut off from other blood vessels when they are raised and removed from surrounding native tissue. The remaining blood supply must then keep the tissue alive until additional blood supply can be formed through angiogenesis.
Sources: en.wikipedia.org
Ipamorelin is a synthetic pentapeptide that stimulates growth hormone release by activating the ghrelin receptor. It is handled as a research tool rather than as a licensed therapeutic product. Its short chain length makes it comparatively simple to synthesize and analyze.
Both bind the same receptor, but ghrelin is a 28-amino-acid hormone with roles in appetite and energy balance. Ipamorelin is a much smaller synthetic peptide selected for growth hormone release with limited effect on appetite signaling in animal models. The full overlap between their effects is not completely mapped.
Most published data come from animal studies and a small number of human trials. Findings on growth hormone release are reasonably consistent, while long-term effects and direct comparisons with other secretagogues remain incompletely studied. Open questions include duration of action across different populations.
Purity is commonly estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection. Mass spectrometry is used to confirm identity and to detect sequence-related impurities. Reported percentages depend on the method and the impurity threshold used.