A practical reference on GHS-R1a: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-14. Anything still debated is marked as such rather than presented as settled.
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。
杂质谱一般包含缺失序列片段、差向异构体、氧化产物以及残留溶剂或反离子，其中组氨酸与芳香残基的氧化常被重点关注。反相色谱中这类杂质往往紧邻主峰洗脱，因此方法需要足够的分离度并经过系统适用性验证。纯度百分比的解读依赖于检测波长与梯度条件，不同实验室公布的数字不宜直接横向比较。参考标准品有助于跨批次对照，但其自身赋值同样需要可追溯来源。
冻干状态下的肽通常比溶液状态更稳定，常规做法是维持 -20 °C 或更低温度、保持干燥并避开强光。复溶后的降解主要来自水解、氧化与脱酰胺，速率受 pH、缓冲液种类、离子强度与温度共同影响，碱性条件一般会加快这些反应。反复冻融会造成聚集与容器吸附损失，分装保存能降低该风险。容器材质与金属离子也可能参与氧化过程，需与操作条件一并考虑。
对 ipamorelin 的常规表征以反相高效液相色谱测定纯度，检测波长多设为 214 nm，因为肽键在该波长有较强吸收。身份确认通常借助电喷雾电离质谱或串联质谱，将实测分子量与理论值逐项比对。序列层面可用肽图分析或氨基酸分析进一步验证。这些手段组合起来，可以分别覆盖纯度、身份与序列三个不同层次的信息。
| Property | Value | Notes |
|---|---|---|
| 分子式 | C38H49N9O5 | 五肽，含非天然氨基酸残基 |
| 分子量 | 711.85 g/mol | 理论值，盐形式可能略有差异 |
| 外观 | 白色至类白色粉末 | 冻干粉常见 |
| 溶解性 | 易溶于水 | 也可溶于部分极性有机溶剂 |
| 储存条件 | -20°C，干燥避光 | 长期保存通常推荐 |
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.
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.
Coral reefs are under stress around the world. In particular, coral mining, agricultural and urban runoff, pollution (organic and inorganic), overfishing, blast fishing, disease, and the digging of canals and access into islands and bays are localized threats to coral ecosystems. Broader threats are sea temperature rise, sea level rise and pH changes from ocean acidification, all associated with greenhouse gas emissions. In 1998, 16% of the world's reefs died as a result of increased water temperature. Approximately 10% of the world's coral reefs are dead. About 60% of the world's reefs are at risk due to human-related activities. The threat to reef health is particularly strong in Southeast Asia, where 80% of reefs are endangered. Over 50% of the world's coral reefs may be destroyed by 2030; as a result, most nations protect them through environmental laws. In the Caribbean and tropical Pacific, direct contact between ~40–70% of common seaweeds and coral causes bleaching and death to the coral via transfer of lipid-soluble metabolites. Seaweed and algae proliferate given adequate nutrients and limited grazing by herbivores such as parrotfish. Water temperature changes of more than 1–2 °C (1.8–3.6 °F) or salinity changes can kill some species of coral. Under such environmental stresses, corals expel their Symbiodinium; without them, coral tissues reveal the white of their skeletons, an event known as coral bleaching.
Kopi luwak (Indonesian pronunciation: [ˈkopi ˈlu.aʔ]), also known as civet coffee, is a coffee that consists of partially digested coffee cherries, which have been eaten and defecated by the Asian palm civet (Paradoxurus hermaphroditus). The cherries are fermented as they pass through a civet's intestines, and after being defecated with other fecal matter, they are collected. Although kopi luwak is a form of processing rather than a variety of coffee, it is known as one of the most expensive coffees in the world, with retail prices reaching $100 per kilogram ($45/lb) for farmed beans and $1,000 per kilogram ($450/lb) for wild-collected beans. Another epithet for it is the "Holy Grail of coffees".
Shimeji (Japanese: シメジ, 占地 or 湿地) is a group of edible mushrooms native to East Asia, but also found in northern Europe. Hon-shimeji (Lyophyllum shimeji) is a mycorrhizal fungus and difficult to cultivate. Other species are saprotrophs, and buna-shimeji (Hypsizygus tessulatus) is now widely cultivated. Shimeji is rich in umami-tasting compounds such as guanylic acid, glutamic acid, and aspartic acid.
After the war, Stalin sought to secure the Soviet Union's western border by installing communist-dominated regimes under Soviet influence in bordering countries. During and in the years immediately after the war, the Soviet Union annexed several countries as Soviet Socialist Republics within the Union of Soviet Socialist Republics. Many of these were originally countries effectively ceded to it by Nazi Germany in the Molotov–Ribbentrop Pact, before Germany invaded the Soviet Union. These later annexed territories include Eastern Poland (incorporated into two different SSRs), Latvia (became Latvia SSR), Estonia (became Estonian SSR), Lithuania (became Lithuania SSR), part of eastern Finland (Karelo-Finnish SSR and annexed into the Russian SFSR) and northern Romania (became the Moldavian SSR). In Hungary, when the Soviets installed a communist government, Mátyás Rákosi was appointed General Secretary of the Hungarian Communist Party, which began one of the harshest dictatorships in Europe under the People's Republic of Hungary. In Bulgaria, toward the end of World War II, the Soviet Union crossed the border and created the conditions for a communist coup d'état on the following night. The Soviet military commander in Sofia assumed supreme authority, and the communists whom he instructed, including Kimon Georgiev (who was not a communist himself, but a member of the elitarian political organization "Zveno", working together with the communists), took full control of domestic politics in the People's Republic of Bulgaria.
Sources: en.wikipedia.org
== Society and culture == Benzocaine is found, particularly in Britain in the 2010s, as an additive in street cocaine and also as a bulking agent in "legal highs". Benzocaine gives a numbing effect similar to cocaine and as a bulking and binding agent it can not be detected once mixed. It is the most popular cutting agent worldwide.
=== 1965 === January 24: Winston Churchill dies. February 18: The Gambia becomes independent from the UK under Commonwealth status. March 18: Alexei Leonov conducts the first extravehicular activity or spacewalk in history from his spacecraft, Voskhod 2 in space. March 23: Ranger 9 transmitted live footage of the surface of the Moon before crashing into its surface. April 24: Dominican Civil War: Forces loyal to former President Juan Bosch overthrow current leader Donald Reid Cabral. June 3: Ed White conducts the first American spacewalk from his spacecraft, Gemini IV. July 14–15: Mariner 4 successfully takes pictures of the surface of Mars. August 5: Beginning of the Indo-Pakistani war of 1965. August 9: Singapore gains independence after being expelled from Malaysia. October 1: Six Indonesian generals are killed by the 30 September Movement during an abortive coup d'état later blamed on the Communist Party of Indonesia. Mass killings of suspected communists begin shortly after. November 1: The Chadian Civil War was waged between rebels and the Chadian government. November 11: The white-dominated government of Rhodesia declares its independence which was regarded as an illegal proclamation by British Prime Minister Harold Wilson. Rhodesia was never formally recognised by any country but receives support from neighboring Portuguese Mozambique and the South African apartheid regime in their war against African guerrillas that determined to oust the white government. November 1965: Venera 3 was launched.
Robert Boyle improved Guericke's design and conducted experiments on the properties of vacuum. Robert Hooke also helped Boyle produce an air pump that helped to produce the vacuum. By 1709, Francis Hauksbee improved on the design further with his two-cylinder pump, where two pistons worked via a rack-and-pinion design that reportedly "gave a vacuum within about one inch of mercury of perfect." This design remained popular and only slightly changed until well into the nineteenth century.
Sources: en.wikipedia.org
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。
生长激素释放激素通过其专用受体起作用，而 ipamorelin 主要作用于胃饥饿素受体。两者可影响生长激素释放，但信号通路和下游效应并不相同。
研究多集中在生长激素释放的急性调节、受体选择性以及不同给药方式下的药代动力学。临床终点研究数量有限，长期结局尚不明确。
肽键在 214 nm 附近有较强吸收，适合检测缺少芳香侧链的短肽。该波长的基线受流动相组成与梯度影响较大。因此流动相与梯度条件需要固定并完整记录。