This is a working overview of 生长激素轴, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-04-16. Anything still debated is marked as such rather than presented as settled.
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。
Practical handling centers on limiting moisture, oxygen, and temperature excursions. Lyophilized material is generally held at or below minus twenty degrees Celsius, protected from light and kept sealed until use. Once reconstituted, solutions are typically kept cold and used within a short window because hydrolysis and microbial growth both accelerate in liquid form. Repeated freeze-thaw cycles are avoided, since they promote aggregation. Vial contents should be inspected for particulates and clarity before analysis, and working aliquots are prepared to reduce the number of times the stock is opened.
Quantitation of the peptide relies mainly on reversed-phase high-performance liquid chromatography with ultraviolet detection, typically at 214 nanometers, where the peptide bond absorbs. Identity is confirmed by mass spectrometry, most often electrospray ionization coupled to liquid chromatography, and by peptide mapping after enzymatic digestion. Because related impurities differ only slightly in sequence or modification, method development emphasizes resolution rather than speed. Purity is usually reported as a percentage of the main peak area, with individual impurities listed separately when they exceed a defined reporting threshold.
| 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.
Binding of tesamorelin to the growth hormone-releasing hormone receptor on anterior pituitary somatotrophs activates a Gs protein pathway, raises cyclic AMP, and triggers release of stored growth hormone into the bloodstream. Because the analogue resists dipeptidyl peptidase-4, its plasma residence time exceeds that of native GHRH, producing a larger and more sustained secretory signal. The released growth hormone then acts on the liver and peripheral tissues to raise insulin-like growth factor 1, which feeds back on the hypothalamus and pituitary. This axis explains both the intended effects on fat distribution and the biological markers used to track them.
Studies of the compound rely on imaging and laboratory endpoints rather than on symptoms alone. Visceral adipose tissue is usually quantified by computed tomography or magnetic resonance imaging at the level of the abdomen, with waist circumference serving as a cheaper but less specific proxy. Blood work tracks insulin-like growth factor 1, fasting glucose, glycated hemoglobin, and lipid fractions. In the pivotal trials the imaging endpoint fell by roughly fifteen to twenty percent over six months, subcutaneous fat changed little, and the visceral fat returned toward baseline after treatment stopped, a pattern that shapes how clinicians discuss durability.
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone (GHRH). Its sequence corresponds to the 44-amino-acid form of human GHRH with a trans-3-hexenoyl group attached to the N-terminal tyrosine. This modification slows enzymatic cleavage and extends the peptide's activity relative to the native hormone. The compound is produced by solid-phase peptide synthesis and supplied as a lyophilized powder. Researchers classify it as a GHRH receptor agonist. Its structure places it in the same family as other growth hormone secretagogues that act on the pituitary.
Binding of tesamorelin to GHRH receptors on pituitary somatotroph cells triggers cyclic AMP signaling and the release of growth hormone into circulation. Because the peptide acts upstream of the growth hormone axis, its effects are partly mediated by hepatic insulin-like growth factor 1 (IGF-1) production. The pulsatile character of endogenous growth hormone secretion is preserved rather than replaced. Whether amplified signaling produces effects beyond those of native GHRH remains an area of ongoing investigation.
A documented effect of tesamorelin is a reduction in visceral adipose tissue in some study populations. Researchers have reported decreases in trunk fat measured by computed tomography alongside changes in lipid markers. The mechanism is thought to involve growth hormone-mediated lipolysis, though the precise contribution of direct versus indirect pathways is not fully resolved. Studies have generally examined defined groups over finite periods, so long-term outcomes are less well characterized. Findings have not been uniform across all trials.
== In iPS cell reprogramming == A number of different cellular processes must take place in order for somatic cells to undergo reprogramming into induced pluripotent stem cells (iPS cells). iPS cell reprogramming, also known as somatic cell reprogramming, can be achieved by ectopic expression of Oct4, Klf4, Sox2, and c-Myc (OKSM). Upon induction, mouse fibroblasts must undergo MET to successfully begin the initiation phase of reprogramming. Epithelial-associated genes such as E-cadherin/Cdh1, Cldns −3, −4, −7, −11, Occludin (Ocln), Epithelial cell adhesion molecule (Epcam), and Crumbs homolog 3 (Crb3), were all upregulated before Nanog, a key transcription factor in maintaining pluripotency, was turned on. Additionally, mesenchymal-associated genes such as Snail, Slug, Zeb −1, −2, and N-cadherin were downregulated within the first 5 days post-OKSM induction. Addition of exogenous TGF-β1, which blocks MET, decreased iPS reprogramming efficiency significantly. These findings are all consistent with previous observations that embryonic stem cells resemble epithelial cells and express E-cadherin. Recent studies have suggested that ectopic expression of Klf4 in iPS cell reprogramming may be specifically responsible for inducing E-cadherin expression by binding to promoter regions and the first intron of CDH1 (the gene encoding for E-cadherin).
The 7 kDa DNA-binding proteins are a family of DNA-binding proteins from Sulfolobales archaea. These proteins bind DNA in a mostly sequence-independent manner, with some preference for G/C rich regions and affinities that differ from each other. They serve a genome-packaing purpose analogous to histones. They are resistant to high temperatures as well as low and high pH.
=== Pathogenic fungi === The glyoxylate cycle may serve an entirely different purpose in some species of pathogenic fungi. The levels of the main enzymes of the glyoxylate cycle, ICL and MS, are greatly increased upon contact with a human host. Mutants of a particular species of fungi that lacked ICL were also significantly less virulent in studies with mice compared to the wild type. The exact link between these two observations is still being explored, but it can be concluded that the glyoxylate cycle is a significant factor in the pathogenesis of these microbes.
The United States occupied Iraq between the toppling of the Ba'athist Iraqi government and the dissolution of the Coalition Provisional Authority on 28 June 2004. Thereafter, the United States remained in Iraq after obtaining United Nations Security Council approvals and resolutions, negotiated with involvement from the Transitional Government of Iraq. On 1 January 2009, the Government of Iraq obtained full responsibility for security in all of Iraq. Consequently, United States Forces – Iraq did not have responsibility for, nor control of, any ground in Iraq. Its mission was limited to defense and security cooperation only.
The first treatments with Adelaide-produced insulin were delivered by Robertson's Medical Science Club colleague, Dr. Trent Champion de Crespigny (Honorary Physician to the Adelaide Children's Hospital). The first treated was gravely-ill 9 years-old Dawson Hanna (1913–1926), at the Adelaide Children's Hospital on 7 January 1923, who lived for another three years. The first adult treated with Adelaide-produced insulin was the comatose and moribund 34 years-old Clifford Harry Cornish (1888–1954), at the Adelaide Hospital on 31 January 1923, who lived for another thirty years. All of the Adelaide-produced insulin used for these treatments had been delivered "free of charge" to the patients.
Sources: en.wikipedia.org
== Causes == The cause of the scarring in UIP may be known (less commonly) or unknown (more commonly). Since the medical term for conditions of unknown cause is "idiopathic", the clinical term for UIP of unknown cause is idiopathic pulmonary fibrosis (IPF). Examples of known causes of UIP include connective tissue diseases (primarily rheumatoid arthritis), drug toxicity, chronic hypersensitivity pneumonitis, asbestosis and Hermansky–Pudlak syndrome.
=== Founding === Five Guys was founded in 1986 by Janie and Jerry Murrell. Jerry and the couple's sons Jim, Matt, Chad, and Ben were the original "Five Guys". The Murrells had a fifth son, Tyler, two years later. Today, all five sons, the current "Five Guys", are involved in the business: Matt and Jim travel the United States visiting stores, Chad oversees training, Ben selects the franchisees, and Tyler runs the bakery. The first Five Guys was in Arlington's Westmont Shopping Center. Buns were baked in the same center by Brenner's Bakery. This location closed, in favor of another in Alexandria, Virginia, at the intersection of King and North Beauregard Streets, which closed on September 21, 2013.
=== Systems biology and systems medicine === Beginning in the 1990s, Hood focused more on cross-disciplinary biology and systems biology. He established in 1992 the first cross-disciplinary biology department, the Molecular Biotechnology Department at the University of Washington. In 2000, he co-founded the Institute for Systems Biology (ISB) in Seattle, Washington to develop strategies and technologies for systems approaches to biology and medicine. He co-led the Hood-Price research lab at ISB with Nathan Price until Price left to join Center for Human Healthspan at the Buck Institute for Research on Aging. Hood pioneered the systems biology concept of considering human biology as a "network of networks." In this model, understanding how systems function requires knowledge of: (1) the components of each network (including genetic, molecular, cellular, organ networks), (2) how these networks inter- and intra-connect, (3) how the networks change over time and undergo perturbations, and (4) how function is achieved within these networks. At the ISB under Hood's direction, genomic, transcriptomic, metabolomic and proteomic technologies are used to understand the "network of networks" and are focused on diverse biological systems (e.g. yeast, mice and humans). Hood applies the notion of systems biology to the study of medicine, specifically to cancer and neurodegenerative disease.
Hypotension (low blood pressure) Dysphoria Tachycardia Malaise Psychomotor impairment It is not believed to be addictive but is known to produce mild withdrawal effects (e.g., anorexia) after abrupt discontinuation.
Sources: en.wikipedia.org
== Etymology and regional names == The name "bilberry" appears to have a Scandinavian origin, possibly from as early as 1577, while the earliest known English use of the name "blueberry" dates back to 1594, appearing in the Acts of Parliament of Scotland. The name "bilberry" is similar to the Danish word bølle for whortleberry with the addition of "berry". In Scandinavian languages, terms for bilberries have names with the meaning "blueberry", such as blåbär in Swedish and blåbær in Danish and Norwegian. The bilberry (especially Vaccinium myrtillus) may be called blaeberry in Scottish and Northern English regional dialects, whortleberry in southern England, and fraochán in Ireland.
=== Fragment based (group contribution) === Analogously, the "partition coefficient"—a measurement of differential solubility and itself a component of QSAR predictions—can be predicted either by atomic methods (known as "XLogP" or "ALogP") or by chemical fragment methods (known as "CLogP" and other variations). It has been shown that the logP of compound can be determined by the sum of its fragments; fragment-based methods are generally accepted as better predictors than atomic-based methods. Fragmentary values have been determined statistically, based on empirical data for known logP values. This method gives mixed results and is generally not trusted to have accuracy of more than ±0.1 units. Group or fragment-based QSAR is also known as GQSAR. GQSAR allows flexibility to study various molecular fragments of interest in relation to the variation in biological response. The molecular fragments could be substituents at various substitution sites in congeneric set of molecules or could be on the basis of pre-defined chemical rules in case of non-congeneric sets. GQSAR also considers cross-terms fragment descriptors, which could be helpful in identification of key fragment interactions in determining variation of activity. Lead discovery using fragnomics is an emerging paradigm. In this context FB-QSAR proves to be a promising strategy for fragment library design and in fragment-to-lead identification endeavours. An advanced approach on fragment or group-based QSAR based on the concept of pharmacophore-similarity is developed.
== Absorption, metabolism and excretion == When found in foods, most pantothenic acid is in the form of CoA or bound to acyl carrier protein (ACP). For the intestinal cells to absorb this vitamin, it must be converted into free pantothenic acid. Within the lumen of the intestine, CoA and ACP are hydrolyzed into 4'-phosphopantetheine. The 4'-phosphopantetheine is then dephosphorylated into pantetheine. Pantetheinase, an intestinal enzyme, then hydrolyzes pantetheine into free pantothenic acid. Free pantothenic acid is absorbed into intestinal cells via a saturable, sodium-dependent active transport system. At high levels of intake, when this mechanism is saturated, some pantothenic acid may also be additionally absorbed via passive diffusion. As a whole, when intake increases 10-fold, absorption rate decreases to 10%. Pantothenic acid is excreted in urine. This occurs after its release from CoA. Urinary amounts are on the order of 2.6 mg/day, but decreased to negligible amounts when subjects in multi-week experimental situations were fed diets devoid of the vitamin. Mutation of pantothenate kinase (the first enzyme in the pathway converting pantothenic acid to CoA) is the cause of pantothenate kinase associated neurodegeneration (PKAN), a rare neurodegenerative disease.
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。
Reversed-phase high-performance liquid chromatography with ultraviolet detection is the standard technique for purity and content. Mass spectrometry provides orthogonal confirmation of identity. The two are normally used together rather than in isolation.