This is a working overview of somatotroph, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-29 and is reviewed periodically as new material appears.
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.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic pentapeptide | Chain of five amino acid residues |
| Molecular mass | Approximately 712 Da | Consistent with a five-residue chain |
| Receptor target | GHS-R1a | Growth hormone secretagogue receptor |
| Primary action | Growth hormone release | Pituitary somatotroph stimulation |
| Research origin | Developed in the 1990s | Small-peptide secretagogue program |
Selectivity distinguishes ipamorelin from first-generation secretagogues such as GHRP-6. At doses that reliably raise growth hormone, it shows little stimulation of adrenocorticotropic hormone or cortisol release in animal models, and it does not markedly raise prolactin or appetite. Binding at GHS-R1a on pituitary somatotrophs triggers calcium influx and pulsatile growth hormone secretion. Because the compound mimics the natural ghrelin signal, the release pattern tends to follow the body's own rhythm rather than producing a sustained elevation.
Most published work on ipamorelin comes from rodent studies and small early-phase human trials. Subcutaneous and intravenous routes have been used, while oral delivery is limited by poor absorption and rapid breakdown in the gut. The reported plasma half-life is short, on the order of two hours, and varies with species and assay method. Whether chronic use produces meaningful clinical benefit remains unresolved, and long-term safety data in humans are sparse. No major regulatory agency has approved the compound as a therapeutic drug.
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, incorporating two non-natural residues that resist enzymatic breakdown. Researchers at Novo Nordisk described the compound in the 1990s while searching for agents that release growth hormone with fewer side effects than earlier secretagogues. The molecule acts as an agonist at the ghrelin receptor, also called GHS-R1a, which is expressed in the pituitary and in several peripheral tissues.
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 is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Researchers at a pharmaceutical company first described it in the 1990s while screening small peptides for growth hormone releasing activity. Its chain contains five amino acid residues, two of which are non-natural building blocks, including 2-aminoisobutyric acid and a naphthylalanine derivative. The molecule was designed to act at the ghrelin receptor while avoiding several effects observed with earlier secretagogues.
At the cellular level, ipamorelin binds the growth hormone secretagogue receptor, also called the ghrelin receptor. Activation of this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to release of growth hormone into circulation. Because release follows a pulsatile pattern, studies often report peak concentration and total area under the curve rather than a single time point. Selectivity for this receptor is the property most frequently discussed in comparative work.
Compared with older secretagogues such as hexarelin or GHRP-6, ipamorelin shows weaker stimulation of cortisol, prolactin, and appetite in the animal models used for early characterization. Whether that selectivity is preserved across longer human exposures remains an open question, because published clinical data are limited in size and duration. Reported effects on food intake are generally described as modest. The compound is therefore treated in the literature as a relatively selective research tool rather than a fully characterized therapeutic agent.
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.
The first-generation Molteno and other nonvalved implants sometimes require the ligation of the tube until the bleb formed is mildly fibrosed and water-tight. This is done to reduce postoperative hypotony—sudden drops in postoperative intraocular pressure. Valved implants, such as the Ahmed glaucoma valve, attempt to control postoperative hypotony by using a mechanical valve. Ab interno implants, such as the Xen Gel Stent, are transscleral implants by an ab interno procedure to channel aqueous humor into the non-dissected Tenon's space, creating a subconjunctival drainage area similar to a bleb. The implants are transscleral and different from other ab interno implants that do not create a transscleral drainage, such as iStent, CyPass, or Hydrus. The ongoing scarring over the conjunctival dissipation segment of the shunt may become too thick for the aqueous humor to filter through. This may require preventive measures using antifibrotic medications, such as 5-fluorouracil or mitomycin-C (during the procedure), or other nonantifibrotic medication methods, such as collagen matrix implant, or biodegradable spacer, or later on create a necessity for revision surgery with the sole or combinative use of donor patch grafts or collagen matrix implant.
=== Epidermal barrier === Necrobiosis, mainly affecting dermis and subcutaneous tissue, can also impact the epidermis. TNF-α and IFN-γ impair keratinocyte function, inhibiting keratinocyte proliferation and migration, two processes essential for reepithelialization and wound closure. Chronic keratinocyte dysfunction can lead to tissue atrophy. Furthermore, inflammatory signaling may downregulate key cell-cell adhesion molecules such as E-cadherin and β-catenin, compromising epidermal tight junctions and leading to skin barrier dysfunction. All of these factors impact the epidermal integrity and barrier.
(The times are half-lives.) Plutonium-239 is further irradiated by a source that has a high neutron flux, several times higher than a conventional nuclear reactor, such as the 85-megawatt High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory in Tennessee, US. The higher flux promotes fusion reactions involving not one but several neutrons, converting 239Pu to 244Cm and then to 249Cm:
In July 2020, Duterte signed the Anti-Terrorism Act of 2020, which expanded the powers of the government to address the country's growing security challenges. In its enactment, the law repealed the Human Security Act of 2007, which was described by the 2020 law's proponents as weak and inadequate. However, the 2020 law received intense criticism, notably from the academia and rights groups, for allegedly being prone to abuse; a total of 37 petitions were filed by several groups asking the Supreme Court to have the law nullified, making the law the most assailed legislation in Philippine history; the Court ultimately upheld the validity of the law in December 2021, but struck two of the law's provisions. As Duterte's term approached its end, the military intensified its efforts against Islamic terrorists, which continued to carry a series of attacks in Mindanao and Sulu; notable among these attacks involved suicide bombing, a tactic not commonly used by Filipino terrorists. In February 2021, Duterte created the National Amnesty Commission, which would process amnesty applications of former rebels and determine their eligibility. Additionally, he expanded his administration's reintegration program to include former violent extremists. From 2016 to 2021, 1,544 ASG members, 971 Bangsamoro Islamic Freedom Fighters members, and 1,427 Dawlah Islamiyah members were reportedly captured, killed, or surrendered.
=== Insects as a novel protein source for pet food === A challenge that is presented when feeding companion animals with food intolerance or sensitivities is finding protein sources that will not irritate their gastrointestinal tracts. Animal protein is a major cause of gastrointestinal problems, and insect protein may be an alternative source for these pets. Insects have the potential to be used as a novel protein in diets for sensitive animals. A novel protein is a protein source to which the animal has not previously been exposed. There are some risks to using novel protein sources, such as contaminants, antinutritional factors (ANFs), and allergens which are not well known. When referring specifically to dog and cat nutrition, the use of alternative protein sources must be able to deliver the ten essential amino acids (EAA) that are not synthesized from the body (including Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Trp and Val). One additional amino acid which is specific to cats who are obligate carnivores by nature is taurine. This requirement is based on the low enzymatic action of cysteine dioxygenase and cysteine sulphinic acid decarboxylase within feline metabolism, where the competing pathway of pyruvate for an energy source overrides taurine synthesis. McCuster et al. created a study to identify amino acid composition of different insects, specifically addressing the presence of taurine in comparison to the National Research Council's (NRC) minimal requirements (MR) for the dog and cat.
Sources: en.wikipedia.org
In 2004, the Uni-President Group introduced Mister Donut in Taiwan through the newly established joint-venture Mister Donut Taiwan Corp., announcing a goal to open 100 outlets in Taiwan in three years.
The Kockums shipyard responsible for the design of the x-stern on Swedish submarines eventually exported it to Australia with the Collins class as well as to Japan with the Sōryū class. With the introduction of the type 212, the German and Italian Navies came to feature it as well. The US Navy with its Columbia class, the British Navy with its Dreadnought class, and the French Navy with its Barracuda class are all about to join the x-stern family. Hence, as judged by the situation in the early 2020s, the x-stern is about to become the dominant technology. When a submarine performs an emergency surfacing, all depth and trim control methods are used simultaneously, together with propelling the boat upwards. Such surfacing is very quick, so the vessel may even partially jump out of the water, potentially damaging submarine systems.
However, it is possible that some isotopes that are now considered stable will be revealed to decay with extremely long half-lives (as happened with bismuth). For each of the 80 stable elements, the number of stable isotopes is given. Only 90 isotopes are stable against any possible decay, and an additional 161 are energetically unstable (see List of nuclides) but have never been observed to decay. Thus, 251 isotopes (nuclides) are stable by definition (including an excited state, tantalum-180m, for which no decay has yet been observed). In April 2019 it was announced that the half-life of xenon-124 had been measured to 1.8 × 1022 years. This is the longest half-life directly measured for any unstable isotope; only the (indirectly measured) half-life of tellurium-128 is longer. Of the chemical elements, only 1 element (tin) has 10 such stable isotopes, 5 have 7 stable isotopes, 7 have 6 stable isotopes, 11 have 5 stable isotopes, 9 have 4 stable isotopes, 5 have 3 stable isotopes, 16 have 2 stable isotopes, and 26 have 1 stable isotope. Additionally, 31 nuclides of the naturally occurring elements have unstable isotopes with a half-life long enough to have survived for the age of the Solar System (108 years or more), and an additional four such nuclides represent three elements (bismuth, thorium, uranium) having no stable isotope. These 35 radioactive naturally occurring nuclides comprise the radioactive primordial nuclides. The total number of primordial nuclides is then 251 (the stable nuclides) plus the 35 radioactive primordial nuclides, for a total of 286.
=== Simplifications === In case of conservative body forces, ∇ × B = 0. For a barotropic fluid, ∇ρ × ∇p = 0. This is also true for a constant density fluid (including incompressible fluid) where ∇ρ = 0. Note that this is not the same as an incompressible flow, for which the barotropic term cannot be neglected. This note seems to be talking about the fact that conservation of momentum says
Sources: en.wikipedia.org
Naturally occurring erbium is composed of 6 stable isotopes, 162Er, 164Er, 166Er, 167Er, 168Er, and 170Er, with 166Er being the most abundant (33.503% natural abundance). Of the artificial radioisotopes characterized, the most stable are 169Er with a half-life of 9.39 d, 172Er with a half-life of 49.3 h, and 160Er with a half-life of 28.58 h. All of the remaining radioactive isotopes have half-lives that are less than 11 h, and the majority of these have half-lives that are less than 4 minutes. This element also has 26 meta states, with the most stable being 149m1Er with a half-life of 8.9 s. The known isotopes of erbium range from 143Er to 180Er. The primary decay mode before the most abundant stable isotope, 166Er, is electron capture, and the primary mode after is beta decay. The primary decay products before 166Er are element 67 (holmium) isotopes, and the primary products after are element 69 (thulium) isotopes. 165Er has been identified as useful for use in Auger therapy, as it decays via electron capture and emits no gamma radiation. It can also be used as a radioactive tracer to label antibodies and peptides, though it cannot be detected by any kind of imaging for the study of its biological distribution. The isotope can be produced via the bombardment of 165Ho with beams of protons or deuterium, a reaction which is especially convenient because 165Ho is a monoisotopic element and relatively inexpensive.
22 November – With Storm Bert set to arrive in Scotland the following day, bringing snow and ice, Police Scotland urges motorists not to travel. 23 November – Police Scotland arrest seven people in connection with Bonfire Night disturbances in the Pollokshields area of Glasgow. 24 November – Alex Cole-Hamilton, the leader of the Scottish Liberal Democrats says his party will vote down the Scottish Government's upcoming budget if it contains even a "penny" promoting Scottish independence. Police charge a senior British Army officer over an incident during which he took decommissioned hand grenades through security at Edinburgh Airport on 16 October. 25 November – 50 non-essential workers are evacuated from the Valaris 120 oil rig 150 miles off the coast of Aberdeen following a crash with a vessel. 26 November – Aberdeen Football Club withdraws an application for a temporary alcohol licence. 27 November – The Scottish Government launches a public consultation on potential sped limit changes that could see the speed limit reduced from 60 mph to 50 mph for cars on single carriageways, but increased from 40 mph to 50 mph for HGV vehicles. HGVs could also have speed limits on dual carriageways increased to 60 mph. 28 November – The Scottish Government announces that all pensioner households will receive a Winter Fuel Payment from Winter 2025–26, with those on Pension Credit receiving £200 or £300 dependent on age and the rest receiving £100. The Scottish Government abandons plans to upgrade the A96 between Aberdeen and Inverness to make it a full dual carriageway by 2030.
Natural uranium (NU or Unat) is uranium with the same isotopic ratio as found in nature. It contains 0.711% uranium-235, 99.284% uranium-238, and a trace of uranium-234 by weight (0.0055%). Approximately 2.2% of its radioactivity comes from uranium-235, 48.6% from uranium-238, and 49.2% from uranium-234. Natural uranium can be used to fuel both low- and high-power nuclear reactors. Historically, graphite-moderated reactors and heavy water-moderated reactors have been fueled with natural uranium in the pure metal (U) or uranium dioxide (UO2) ceramic forms. However, experimental fuelings with uranium trioxide (UO3) and triuranium octaoxide (U3O8) have shown promise. The 0.72% uranium-235 is not sufficient to produce a self-sustaining critical chain reaction in light water reactors or nuclear weapons; these applications must use enriched uranium. Nuclear weapons take a concentration of 90% uranium-235, and light water reactors require a concentration of roughly 3% uranium-235. Unenriched natural uranium is appropriate fuel for a heavy-water reactor, like a CANDU reactor. On rare occasions, earlier in geologic history, when uranium-235 was more abundant, uranium ore was found to have naturally engaged in fission, forming natural nuclear fission reactors. Uranium-235 decays at a faster rate (half-life of 700 million years) compared to uranium-238, which decays extremely slowly (half-life of 4.5 billion years). Therefore, a billion years ago, there was more than double the uranium-235 compared to now.
Sources: en.wikipedia.org
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.
In animal studies it showed greater selectivity for growth hormone release, with less effect on cortisol and adrenocorticotropic hormone than compounds such as GHRP-6. This selectivity is one of the most frequently cited features in preclinical literature. Whether the same profile applies in other contexts is not fully established.
The receptor-level events are reasonably well described, but the full range of downstream effects is not. Studies have reported activity in tissues beyond the pituitary, including the gut. How these observations translate across species and conditions remains an open question.
两者都是 GHS-R1a 激动剂，但 ipamorelin 在研究中显示出更高的生长激素释放选择性。早期资料显示它对皮质醇、催乳素与食欲的刺激弱于 GHRP-6。这些差异是相对程度，而非绝对区分。