非天然氨基酸 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 2025-11-19 and is reviewed periodically as new material appears.
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.
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.
Ipamorelin is a synthetic pentapeptide that acts on the growth hormone secretagogue receptor, also known as the ghrelin receptor. Its sequence contains five amino acid residues, including a non-natural residue that increases stability against enzymatic breakdown. The compound was developed in the 1990s as part of research into small peptides that stimulate pituitary hormone release. Unlike larger protein hormones, it can be produced by solid-phase peptide synthesis and characterized by standard analytical methods.
At the receptor level, ipamorelin binds GHS-R1a and triggers signaling through Gq-coupled pathways. Activation leads to calcium release and downstream effects in pituitary somatotroph cells. These events promote the release of growth hormone into circulation. The response depends on the presence of the receptor and on the physiological state of the animal or tissue studied. Because the receptor is also found in other tissues, effects beyond the pituitary have been examined in laboratory models, though the extent of those effects remains an area of ongoing study.
One distinguishing feature reported in animal studies is selectivity. Ipamorelin stimulated growth hormone release with limited elevation of adrenocorticotropic hormone or cortisol compared with earlier secretagogues such as GHRP-6. This pattern has been described as more selective for the growth hormone axis. The finding comes mainly from preclinical work, and the degree to which it holds across species and doses is not fully settled. Reports also describe effects on gastric motility in animal models, suggesting activity outside the pituitary, though the clinical relevance of this observation is uncertain.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H49N9O5 | Pentapeptide with amidated C-terminus |
| Molecular weight | 711.85 g/mol | Monoisotopic mass |
| Primary receptor | GHS-R1a | Ghrelin receptor, Gq/11 coupled |
| Peptide class | Synthetic pentapeptide | Contains two non-natural residues |
| Reported selectivity | Lower cortisol and prolactin effect | Observed in animal and early human work |
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.
Lyophilized material is generally stored frozen and protected from light and moisture. Typical recommendations place dry powder at temperatures well below freezing, while reconstituted solutions are kept cold and used within a defined window. Repeated freezing and thawing should be avoided because it can promote aggregation and loss of material. The choice of solvent matters as well; compatibility with the intended diluent should be checked before preparation. These handling practices aim to preserve both the quantity and the integrity of the peptide.
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.
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.
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 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。
=== Serving chicken without antibiotics === In February 2014, Chick-fil-A announced plans to serve chicken raised without antibiotics in its restaurants nationwide within five years, the first fast-food restaurant to make this commitment. This was implemented by May 2019. Later the company stated that "to maintain supply of the high-quality chicken", they would shift from a policy of No Antibiotics Ever (NAE) to No Antibiotics Important To Human Medicine (NAIHM) starting in the spring of 2024. In March 2024, Chick-fil-A announced it would depart from the company's previous commitment of using only "antibiotic-free" chicken.
Bread is a significant part of German cuisine, with German bakeries producing about 600 main types of bread and 1,200 types of pastries and rolls (Brötchen). German cheeses account for about 22% of all cheese produced in Europe. Germans produce their ubiquitous sausages in almost 1,500 varieties, including Bratwurst and Weißwurst. The national alcoholic drink is beer. Germany's beer consumption per capita stood at 110 litres (24 imp gal; 29 US gal) in 2013 and remains among the highest in the world. German beer purity regulations date back to the 16th century. Wine has become popular in many parts of the country, especially near the German wine regions. In 2019, Germany was the ninth-largest wine producer in the world. The 2018 Michelin Guide awarded eleven restaurants in Germany three stars, giving the country a cumulative total of 300 stars.
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Sources: en.wikipedia.org
The Green Berets would become actively involved against the Iranian-backed Special Groups, TF-17 relied a good deal on the Green Berets mentoring teams with the ISOF, the Green Berets placed ODA's in outfits such as the INIS and the Iraqi commando brigade. The ODA's consisted of 20 men and became — during the course of 2007 — the key to coalition operations in provinces such as Dhi Ghar or Maysan, the teams ensured that operations in the Shia militant strongholds had an Iraqi face to them — something of great symbolic importance to the US relationship with the Iraqi government. Green Berets and Polish GROM conducted Operation Jackal against insurgents in Diwaniyah in 2007. During May and June 2007, many Shia arrest operations were conducted by the British SAS and TF-17s Green Berets and Iraqi commandos led to Muqtada al-Sadr to initially flee to Iran, and in August he declared a Mahdi Army ceasefire with the coalition.
=== Later history === In the 1960s, virologist and cancer researcher Chester M. Southam injected HeLa cancer cells into patients at the Jewish Chronic Disease Hospital. When three doctors resigned after refusing to inject patients without their consent, the experiment gained considerable media attention. The NIH was a major source of funding for Southam's research and required all research involving human subjects to obtain their consent before any experimentation. Upon investigating all of their grantee institutions, the NIH discovered that the majority of them did not protect the rights of human subjects. From then on, the NIH has required all grantee institutions to approve any research proposals involving human experimentation with review boards. In 1967, the Division of Regional Medical Programs was created to administer grants for research for heart disease, cancer, and strokes. That same year, the NIH director lobbied the White House for increased federal funding to increase research and the speed with which health benefits could be brought to the people. An advisory committee was formed to oversee the further development of the NIH and its research programs. By 1971, cancer research was in full force, and President Nixon signed the National Cancer Act, initiating a National Cancer Program, President's Cancer Panel, National Cancer Advisory Board, and 15 new research, training, and demonstration centers. Funding for the NIH has often been a source of contention in the US Congress, serving as a proxy for the political currents of the time.
Nicotinamide adenine dinucleotide (NAD+), a derivative of vitamin B3 (niacin), is an important coenzyme that acts as a hydrogen acceptor. Hundreds of separate types of dehydrogenases remove electrons from their substrates and reduce NAD+ into NADH. This reduced form of the coenzyme is then a substrate for any of the reductases in the cell that need to transfer hydrogen atoms to their substrates. Nicotinamide adenine dinucleotide exists in two related forms in the cell, NADH and NADPH. The NAD+/NADH form is more important in catabolic reactions, while NADP+/NADPH is used in anabolic reactions.
Sources: en.wikipedia.org
=== Upper motor neuron syndrome === Botulinum toxin type-A is now a common treatment for muscles affected by the upper motor neuron syndrome (UMNS), such as cerebral palsy, for muscles with an impaired ability to effectively lengthen. Muscles affected by UMNS frequently are limited by weakness, loss of reciprocal inhibition, decreased movement control, and hypertonicity (including spasticity). In January 2014, botulinum toxin was approved by UK's Medicines and Healthcare products Regulatory Agency (MHRA) for the treatment of ankle disability due to lower limb spasticity associated with stroke in adults. Joint motion may be restricted by severe muscle imbalance related to the syndrome, when some muscles are markedly hypertonic, and lack effective active lengthening. Injecting an overactive muscle to decrease its level of contraction can allow improved reciprocal motion, so improved ability to move and exercise.
== List of death row inmates granted clemency by the President == 1978: Mohamad Kunjo s/o Ramalan, a Singaporean convicted of murdering a lorry driver in 1975 and sentenced to hang in 1976. After losing his appeals against his sentence over the next two years, he filed for clemency, which was granted by President Benjamin Sheares in 1978. His death sentence was commuted to life imprisonment. 1980: Bobby Chung Hua Watt, a Singaporean convicted of murdering his brother-in-law's brother in 1975. He was found guilty of murder and condemned to hang. After losing his appeal against his death sentence, he was initially scheduled to be executed on 18 January 1980. However, on 15 January 1980, President Benjamin Sheares granted him clemency and his death sentence was commuted to life imprisonment. He was released from prison in 1993 for good behaviour after serving at least two-thirds of his life sentence. 1983: Siti Aminah binte Jaffar, a Singaporean convicted of drug trafficking in 1977 and sentenced to death in 1978 along with her lover, Anwar Ali Khan. The two of them appealed to President Devan Nair for clemency in 1983. Anwar's plea was rejected and he was executed, but Siti's was accepted and she had her death sentence changed to life imprisonment. She was released from prison in 1991. 1993: Sim Ah Cheoh, a Singaporean convicted of drug trafficking in 1985 and sentenced to death in 1988 along with her two accomplices.
== History == Pharmaceutical company Johnson & Johnson's Ortho Research Laboratory wrote that case histories of his therapy, "were quite remarkable and your concepts most intriguing" and ICN Pharmaceuticals replied, "The results you have obtained with this drug in the treatment of gangrene have been most spectacular", but DeMarco was never able to commercialize the therapy beyond his own medical practice. Swiss pharmaceutical company Debiopharm S.A. replied, "Drug induced cell regeneration appears to be a revolutionary new form of treatment which is bound to be perceived as highly controversial by several regulatory agencies. We are not in a position to take the considerable time and risk involved in convincing the bureaucrats." Thus although intrigued, the pharmaceutical companies never showed a serious interest in developing his product. Regenerative medicine was a new field at the time and DeMarco likened the companies' antipathy of his discovery to the history of penicillin; although discovered in 1928, penicillin was not mass-produced until 1941 when production became a top priority World War II project to reduce the infection casualty rate. DeMarco's clinical use of a drug not approved by the U.S. Food and Drug Administration came to the attention of regulators in both New Jersey and Pennsylvania, leading to the suspension of his license to practice and the seizure of his supply of procaine hydrochloride, which investigators later found to be contaminated and mislabeled. The New Jersey Department of Health traced 64 cases of infectious hepatitis to Dr. DeMarco.
Tim Hortons is popularly known as "Timmies" or "Timmy's". The ubiquity of Tim Hortons, through the wide expansion of its outlets, makes it a prominent feature of Canadian life; Canadians eat more donuts per capita and have more donut outlets per capita than any other nation. Tim Hortons' prevalence in the coffee and donut market has led to its branding as a Canadian cultural icon. The media routinely refer to its iconic status, despite this being a relatively recent development; there were only a few outlets before the chain's expansion in the late 1990s and 2000s. A series of Tim's television commercials promotes this idea by showing vignettes of Canadians abroad and their homesickness for Tim Hortons. Canadian author Pierre Berton once wrote: "In so many ways the story of Tim Hortons is the essential Canadian story. It is a story of success and tragedy, of big dreams and small towns, of old-fashioned values and tough-fisted business, of hard work and of hockey." Commentator Rex Murphy posited that the reason Tim Hortons "transmuted into a hallowed piece of Canadiana" was perhaps consumers' "reverse-preference" against the sudden penetration of Starbucks in the 1990s. Other commentators have bemoaned the rise of Tim Hortons as a national symbol.
Sources: en.wikipedia.org
It is a synthetic pentapeptide belonging to the growth hormone secretagogue family. Its principal characterized target is the ghrelin receptor, also called GHS-R1a. The molecule contains non-natural amino acids and an amidated C-terminus.
Both act at the same G protein-coupled receptor, but ipamorelin is a short synthetic peptide with modified residues rather than the natural 28-amino-acid hormone. Reports describe weaker effects on appetite and on cortisol or prolactin release than those seen with ghrelin. Its resistance to enzymatic breakdown also differs from that of the natural ligand.
Receptor binding and downstream calcium signaling are well characterized in cell-based systems. Effects measured in whole organisms are less consistent across studies and species. The extent to which selective receptor behavior drives the observed hormonal profile is still debated.
It acts on the growth hormone secretagogue receptor, GHS-R1a, which is also the receptor for ghrelin. Binding triggers intracellular signaling that promotes growth hormone release from the pituitary. The interaction is the basis for its classification as a secretagogue.