This is a working overview of growth hormone, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-03 and is reviewed periodically as new material appears.
作用位置在垂体前叶。tesamorelin 与 GHRH 受体结合后激活腺苷酸环化酶，升高细胞内 cAMP，再经蛋白激酶 A 通路促进生长激素的合成与释放。由于它作用于内源调控节点，生长激素仍以脉冲方式分泌，而不是被持续抬升到固定水平。生长激素随后在肝脏等组织诱导胰岛素样生长因子 1 产生，构成完整的生长激素轴响应。
研究背景集中在特定人群的体成分改变，尤其是与脂肪分布异常相关的内脏脂肪堆积。不同地区对它的监管状态与获批适应症并不一致，部分市场仅限特定诊断人群使用。在一般人群中的长期效应、与其他激素的相互作用以及停药后的维持情况仍属开放问题，现有数据不足以给出普遍结论。
Pharmacodynamic studies show that tesamorelin reduces visceral adipose tissue more than subcutaneous adipose tissue in the studied population. This selectivity may relate to differences in blood flow and hormone sensitivity between fat depots. Effects on glucose metabolism and insulin sensitivity have been investigated, with some trials reporting modest changes and others showing stability. The precise relationship between growth hormone exposure, IGF-1 levels, and visceral fat loss remains an active area of analysis.
Tesamorelin binds to growth hormone-releasing hormone receptors on somatotroph cells in the anterior pituitary. Receptor activation increases intracellular cyclic AMP and promotes synthesis and secretion of growth hormone. Because the peptide mimics endogenous GHRH, it amplifies the normal pulsatile release of growth hormone rather than providing exogenous growth hormone directly. This upstream action distinguishes tesamorelin from recombinant growth hormone preparations and from growth hormone secretagogues that act at different receptors.
Stimulated growth hormone release leads to hepatic production of insulin-like growth factor 1, a key mediator of many growth hormone effects. In clinical studies, tesamorelin increased IGF-1 levels in a dose-dependent manner, although the response varies among individuals. The drug's effect on visceral fat is thought to involve growth hormone-mediated lipolysis and altered adipocyte metabolism. Muscle mass and lean body mass have also been assessed as secondary outcomes, but changes are generally smaller and less consistent than fat reductions.
| 性质 | 取值 | 备注 |
|---|---|---|
| 分子类型 | 合成四十四肽 | GHRH 类似物 |
| N 端修饰 | 反式-3-己烯酰基 | 延缓酶切 |
| 分子量 | 约 5135 Da | 依序列与修饰 |
| 受体靶点 | 垂体 GHRH 受体 | 经 cAMP 通路 |
| 常见同义名 | GHRH(1-44) 类似物 | 文献通用称法 |
Tesamorelin binds to growth hormone-releasing hormone receptors on the surface of pituitary somatotroph cells. This binding activates adenylate cyclase, raising intracellular cyclic AMP levels and triggering the release of growth hormone into circulation. The elevated growth hormone then stimulates hepatic production of insulin-like growth factor 1. Because the effect is mediated through the endogenous axis, secretion remains subject to feedback regulation. This distinguishes it from direct growth hormone administration, which bypasses pituitary control entirely.
Clinical investigation has focused on HIV-associated lipodystrophy, a condition in which antiretroviral therapy contributes to abnormal fat distribution. Excess visceral adipose tissue accumulates in the abdomen while peripheral fat may be lost. Tesamorelin was evaluated for reducing this visceral fat depot, with trials measuring changes in abdominal fat by imaging rather than by body weight alone. The rationale rests on the known lipolytic effects of growth hormone. Effects on visceral fat are documented, while long-term outcomes regarding cardiovascular risk remain less clearly established.
Tesamorelin binds the growth hormone–releasing hormone receptor on pituitary somatotroph cells. The receptor signals through the Gs protein, raising intracellular cAMP and activating protein kinase A. That cascade triggers release of stored growth hormone in pulses rather than a steady stream. Because the drug acts at the receptor that normally controls this process, its effect depends on the body's own signaling architecture rather than on a synthetic pathway. The resulting hormone profile reflects the timing of each pulse, not only its size.
Measured responses usually involve growth hormone and insulin-like growth factor 1, known as IGF-1. Growth hormone rises in bursts and is difficult to sample reliably, while IGF-1 shifts more slowly and can be assessed from a single blood draw. Studies therefore treat IGF-1 as the more practical pharmacodynamic marker. Both are indirect, showing that the receptor was engaged rather than that the peptide reached a particular concentration. Direct exposure measurement requires an assay aimed at the molecule itself.
Tenascin X (TN-X), also known as flexillin or hexabrachion-like protein, is a 450 kDa glycoprotein, a member of the tenascin family, that is expressed in connective tissues. In humans it is encoded by the TNXB gene. The TN-X protein is expressed in many parts of the human body, including the skin, muscles, kidneys, blood vessels, and digestive tract. Deficiencies in the TN-X protein due to mutations or not enough of it being produced (haploinsufficiency) can lead to a rare condition called classical-like Ehlers–Danlos syndrome (EDS). People with EDS may have loose joints and weak tissues because their bodies make defective collagen.
An antihemorrhagic (British English: antihaemorrhagic) agent is a substance that promotes hemostasis (a process which stops bleeding). It may also be known as a hemostatic (also spelled haemostatic) agent. Antihemorrhagic agents used in medicine have various mechanisms of action:
=== Differential diagnosis === Several disorders share some characteristics with EDS. For example, in cutis laxa, the skin is loose, hanging, and wrinkled. In EDS, the skin can be pulled away from the body, but is elastic and returns to normal when let go. In Marfan syndrome, the joints are very mobile, and similar cardiovascular complications occur. People with a "marfanoid" appearance are often tall and thin with long arms and legs and "spidery" fingers, while EDS phenotypes vary considerably. Certain subtypes of EDS may involve short stature, large eyes, and the appearance of a small mouth and chin, due to a small palate. The palate can have a high arch, causing dental crowding. Blood vessels can sometimes be easily seen through translucent skin, especially on the chest. The genetic connective tissue disorder Loeys–Dietz syndrome also has symptoms that overlap with EDS. In the past, Menkes disease, a copper metabolism disorder, was thought to be a form of EDS. People are commonly misdiagnosed with fibromyalgia, bleeding disorders, or other disorders that can mimic EDS symptoms. Because of these similar disorders and complications that can arise from an unmonitored case of EDS, a correct diagnosis is important. Pseudoxanthoma elasticum is worth consideration in diagnosis.
=== Physical and atomic === Rutherfordium is expected to be a solid under normal conditions and have a hexagonal close-packed crystal structure (c/a = 1.61), similar to its lighter congener hafnium. It should be a metal with density ~17 g/cm3. The atomic radius of rutherfordium is expected to be ~150 pm. Due to relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, Rf+ and Rf2+ ions are predicted to give up 6d electrons instead of 7s electrons, which is the opposite of the behavior of its lighter homologs. When under high pressure (variously calculated as 72 or ~50 GPa), rutherfordium is expected to transition to body-centered cubic crystal structure; hafnium transforms to this structure at 71±1 GPa, but has an intermediate ω structure that it transforms to at 38±8 GPa that should be lacking for rutherfordium.
=== Microbial growth === Since the main method of microbial decontamination for freeze drying is the low-temperature dehydration process, spoilage organisms and pathogens resistant to these conditions can remain in the product. Although microbial growth is inhibited by the low moisture conditions, it can still survive in the food product. An example of this is a viral hepatitis A outbreak that occurred in the United States in 2016, associated with frozen strawberries. If the product is not properly packaged and/or stored, the product can absorb moisture, allowing the once inhibited pathogens to begin reproducing as well.
Sources: en.wikipedia.org
The taste of soy sauce is predominated by saltiness, followed by moderate umami, sweetness, and finally slight bitterness, which is hard to perceive due to the masking effect of other tastes. The overall flavor of soy sauce is a result of the balance and interaction among different taste components. The saltiness is largely attributed to the presence of NaCl (common salt) in brine. The sugars hydrolyzed from starch add sweetness into soy sauce. Umami is largely caused by the presence of free amino acids, mainly glutamine and aspartic acid. Sodium from the brine and disodium ribonucleotides from the soy also add to the umami. Other amino acids cause additional basic flavors, with sweet coming from Ala, Gly, Ser, and Thr; bitter coming from Arg, His, Ile, Leu, Met, Phe, Trp, Tyr, and Val; and no taste from Cys, Lys, and Pro. The amino-acid nitrogen content, an indication of the free amino acid concentration, is used in China for grading soy sauce. The highest "special grade" is defined at ≥ 0.8 g/100 mL. Despite a large variety of volatile and odorant compounds that have been identified in soy sauce, the food product per se does not present a strong aroma. Alcohols, acids, esters, aldehydes, ketones, phenols, heterocyclic compounds, alkynes and benzenes have been identified in Chinese soy sauces. An explanation for this observation is that the aroma of soy sauce does not depend largely on the aroma-active compounds. The subtle aroma is a result of a "critical balance" achieved among all volatile and odorant compounds, whose respective concentrations are relatively low.
=== Monocyte activation test === The monocyte activation test (MAT) uses the monocytes in human blood in vitro to detect pyrogens. It was added to the European Pharmacopoeia in 2010 and accepted by the FDA in 2012.
== Rivalries == Essendon's biggest rivals are Carlton, Richmond, and Collingwood, as these teams and Essendon are the four biggest and most supported clubs in Victoria. Matches between the clubs are often close regardless of form and ladder positions. If out of the race themselves, all four have the desire to deny the others a finals spot or a premiership. Essendon also has a fierce rivalry with Hawthorn, stemming from excessive on-field violence in the 1980s, perhaps reaching its zenith with the infamous Line in the Sand Match in 2004. Additionally, Essendon has a three-decade rivalry with the West Coast Eagles.
==== Non-selective ==== α-MSH β-MSH γ-MSH ACTH Afamelanotide Bremelanotide Melanotan II Modimelanotide Setmelanotide — MC4 receptor agonist which is FDA approved to help with chronic weight management in those with pathogenic (or uncertain) variants in POMC and certain related genes.
Sources: en.wikipedia.org
tesamorelin 属 GHRH 类似物，作用于垂体受体以促进内源生长激素释放；生长激素本身是直接补充的外源激素。两者在给药逻辑、作用位点和反馈调控路径上并不相同。
作为多肽，它难以通过胃肠道吸收，通常需要注射给药。口服会因消化酶降解而失去活性，因此文献中讨论的都是注射途径。
公开研究多集中在内脏脂肪、体成分分布以及与生长激素轴相关的代谢指标。长期安全性和在普通人群中的适用性尚缺乏一致结论。
It targets the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Binding stimulates cyclic AMP signaling and growth hormone secretion. This is the same receptor used by endogenous GHRH.