IGF-1 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-05-10. Numbers and descriptions here follow the published literature rather than marketing material.
Signaling begins at the GHRH receptor, a class B G protein-coupled receptor displayed on somatotroph cells of the anterior pituitary. Receptor occupancy activates Gs proteins, which raise adenylyl cyclase activity and intracellular cyclic AMP, in turn driving protein kinase A dependent pathways. The downstream output is synthesis and pulsatile secretion of growth hormone into the bloodstream. Hepatic tissue and peripheral sites respond by increasing insulin-like growth factor 1 production. Somatostatin and IGF-1 itself supply negative feedback that caps the size and duration of each secretory burst.
Metabolic interest in this compound centers on fat distribution rather than on hormone levels alone. Imaging trials in adults with excess abdominal fat report reductions in visceral adipose tissue, while subcutaneous depots change comparatively little. Growth hormone and IGF-1 are presumed to carry the effect, but the separate contribution of each is not firmly established. Whether these changes persist after treatment stops, and whether they alter longer-term health outcomes, remain open questions that published work does not answer consistently.
Tesamorelin is a synthetic peptide of forty-four amino acids whose sequence reproduces human growth hormone-releasing hormone. Its distinguishing feature sits at the amino terminus, where a trans-3-hexenoyl group replaces the free amine. That acylation slows cleavage by dipeptidyl peptidase IV, an enzyme that otherwise removes the first two residues and inactivates the natural hormone quickly. The modified peptide therefore persists longer in circulation while keeping the same receptor target. It is handled as a lyophilized solid and dissolved shortly before use.
Several related peptides act on the same receptor, including sermorelin, a shorter GHRH fragment, and modified analogs such as CJC-1295 and modified GRF(1-29) that are common in research settings rather than approved products. Tesamorelin differs from growth hormone itself in that it acts upstream, prompting the pituitary to release the hormone through physiological signaling rather than supplying it directly. Terminology in the literature distinguishes GHRH analogs, growth hormone secretagogues, and recombinant growth hormone, although popular discussion often blurs these categories together. Precise naming matters when comparing study results.
Tesamorelin is a synthetic peptide of 44 amino acids that reproduces the sequence of human growth hormone-releasing hormone (GHRH) and carries a trans-3-hexenoyl group on its N-terminal tyrosine. That small fatty-acid modification blocks cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GHRH in plasma. The result is a molecule with a longer circulating half-life than the natural hormone while retaining the same receptor target. It is supplied as a lyophilized powder for reconstitution and belongs to the broader class of GHRH analogs studied for effects on pituitary growth hormone secretion.
Development work on the compound, originally designated TH9507, focused on conditions in which reduced growth hormone signaling is thought to contribute to altered body composition. The United States Food and Drug Administration approved it in 2010 for the treatment of excess visceral abdominal fat in adults with human immunodeficiency virus infection and lipodystrophy. Later research examined other populations, including adults with mild cognitive impairment, where a large trial did not meet its primary endpoints. This mixed record illustrates how a single mechanism can produce clear effects in one setting and inconclusive results in another.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic 44-residue peptide | GHRH analog backbone |
| Approximate molecular mass | 5136 Da | Varies with counterion and hydration state |
| N-terminal group | trans-3-hexenoyl | Increases resistance to dipeptidyl peptidase IV |
| Primary receptor | GHRH receptor (GHRHR) | Class B G protein-coupled receptor on somatotrophs |
| Principal mediator | IGF-1 | Rises indirectly after growth hormone release |
监管记录显示，特沙莫瑞林于 2010 年在美国首次获得批准，用于人类免疫缺陷病毒感染相关的脂肪营养不良患者。批准依据来自降低内脏脂肪的临床试验，而非体重或瘦体重的普遍改善。后续出现了不同制剂版本，但其核心适应症保持一致。关于长期心血管结局和死亡率影响，现有证据仍不充分。
在临床研究之外，特沙莫瑞林常被讨论为生长激素分泌促进剂，但这一说法需要限定。它并不等同于生长激素本身，也不属于普通减重药物。部分研究关注其减少腹部脂肪和改善脂质谱的潜力，另一些研究则关注胰岛素抵抗和 IGF-1 升高等信号。这些效应的临床意义仍在评估中，尚未形成统一结论。
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。
tesamorelin 是一种人工合成的四十四肽，序列与内源性生长激素释放激素（GHRH）的 1-44 片段一致，区别在于 N 端加接了一个反式-3-己烯酰基。该修饰抑制二肽基肽酶 IV 的快速切割，从而延长分子在循环中的存留时间。作为肽类分子，它难以经胃肠道吸收，文献中讨论的均是注射途径。分类上通常把它归为 GHRH 类似物，以区别于生长激素本身。
=== Tricyclic antidepressant === Tricyclic antidepressants (TCAs) have a different side effect profile than SSRIs. In a study of inpatients the tricyclic antidepressant amitriptyline, in particular, appears to be more effective.
Fowler was initially skeptical but was ultimately convinced that Bohr was correct, and by 1915 "spectroscopists had transferred [the Pickering–Fowler series] definitively [from hydrogen] to helium." Bohr's theoretical work on the Pickering series had demonstrated the need for "a re-examination of problems that seemed already to have been solved within classical theories" and provided important confirmation for his atomic theory. In 1938, Russian physicist Pyotr Leonidovich Kapitsa discovered that helium-4 has almost no viscosity at temperatures near absolute zero, a phenomenon now called superfluidity. This phenomenon is related to Bose–Einstein condensation. In 1972, the same phenomenon was observed in helium-3, but at temperatures much closer to absolute zero, by American physicists Douglas D. Osheroff, David M. Lee, and Robert C. Richardson. The phenomenon in helium-3 is thought to be related to pairing of helium-3 fermions to make bosons, in analogy to the Cooper pairs of electrons producing superconductivity. In 1961, Vignos and Fairbank reported the existence of a different phase of solid helium-4, designated the gamma-phase. It exists for a narrow range of pressure between 1.45 K (−271.70 °C; −457.06 °F) and 1.78 K (−271.37 °C; −456.47 °F).
=== Coating === Optically transparent, multilayer films made from graphene oxide are impermeable under dry conditions. Exposed to water (or water vapor), they allow passage of molecules below a certain size. The films consist of millions of randomly stacked flakes, leaving nano-sized capillaries between them. Closing these nanocapillaries using chemical reduction with hydroiodic acid creates "reduced graphene oxide" (r-GO) films that are completely impermeable to gases, liquids or strong chemicals greater than 100 nanometers thick. Glassware or copper plates covered with such a graphene "paint" can be used as containers for corrosive acids. Graphene-coated plastic films could be used in medical packaging to improve shelf life. Layer-by-layer coatings based on amine-modified graphene oxide and Nafion show excellent antimicrobial performance that is not compromised when heated for 2 hours at 200 °C.
21 April – Mark Menzies quits the Conservative Party and says he will stand down from Parliament at the next election. Robin Swann, who is the perspective Ulster Unionist candidate for South Antrim, announces he will step down from his post as Northern Ireland's Health Minister once the general election campaign begins. 22 April – Parliament passes the Safety of Rwanda Bill, with plans to deport the first asylum seekers to Kigali in July. Two men, including a parliamentary researcher, are charged with spying for China after providing information that could be "useful to an enemy". Conservative councillor Richard Solesbury-Timms, who represents Middleton Cheney on West Northamptonshire Council, leaves the party to sit as an independent citing the party's dealing with allegations against the council leader. 23 April – Patrick Harvie says he will resign as co-leader of the Scottish Greens if the party votes to end its coalition agreement with the SNP. Alliance Party MLA Patrick Brown resigns his South Down seat in the Northern Ireland Assembly, citing personal reasons for doing so. 24 April – Rishi Sunak vows to increase UK defence spending to 2.5% of GDP by 2030. Labour unveils its plans for improvements to train services, which include automatic refunds for delays, a "best price" guarantee and improved internet coverage. Jeffrey Donaldson appears at Newry Magistrates' Court to face charges of historic child abuse. Johnny Timpson, the UK's inaugural disability ambassador, resigns over the UK government's policy of clawing back benefit overpayment.
Nicholas Kemmer of the Cambridge team independently proposed the same name, based on the same reasoning as the Berkeley team. Seaborg originally considered the name "plutium", but later thought that it did not sound as good as "plutonium". He chose the letters "Pu" as a joke, in reference to the interjection "P U" to indicate an especially disgusting smell, which passed without notice into the periodic table. Alternative names considered by Seaborg and others were "ultimium" or "extremium" because of the erroneous belief that they had found the last possible element on the periodic table. Hahn and Strassmann, and independently Kurt Starke, were at this point also working on transuranic elements in Berlin. It is likely that Hahn and Strassmann were aware that plutonium-239 should be fissile. However, they did not have a strong neutron source. Element 93 was reported by Hahn and Strassmann, as well as Starke, in 1942. Hahn's group did not pursue element 94, likely because they were discouraged by McMillan and Abelson's lack of success in isolating it when they had first found element 93. However, since Hahn's group had access to the stronger cyclotron at Paris at this point, they would likely have been able to detect plutonium had they tried, albeit in tiny quantities (a few becquerels).
Sources: en.wikipedia.org
=== Distribution === Estradiol is rapidly distributed throughout the body, with a distribution phase of about 6 minutes following intravenous injection. Estradiol is taken up into cells via passive diffusion due to its lipophilicity. Due to binding to the ERs, estradiol is preferentially concentrated in tissues with the highest ER content. In animals, these tissues have included the uterus, vagina, mammary glands, pituitary gland, hypothalamus, other brain regions, adipose tissue, liver, and adrenal glands, among other tissues. In contrast to estradiol, due to its low affinities for the ERs, estrone is not accumulated in target tissues. Estradiol has been found to cross the blood–brain barrier in rhesus monkeys. The volume of distribution of estradiol has been found to be 0.85 to 1.17 L/kg. In another study however, its volume of distribution was only 0.082 ± 0.015 L/kg (4.8 L in women of average weight 58.4 kg). In terms of plasma protein binding, estradiol is bound loosely to albumin and tightly to SHBG, with approximately 97 to 98% of estradiol bound to plasma proteins. In the circulation, approximately 38% of estradiol is bound to SHBG and 60% is bound to albumin, with 2 to 3% free or unbound. However, with oral estradiol, there is an increase in hepatic SHBG production and hence SHBG levels (e.g., +50%), and this results in a relatively reduced fraction of free estradiol. As only free estradiol that is not bound to plasma proteins or SHBG is biologically active, this may reduce the potency of oral estradiol by some degree.
== Commercial uses == Under the brand names Equal, NutraSweet, and Canderel, aspartame is an ingredient in approximately 6,000 consumer foods and beverages sold worldwide, including (but not limited to) diet sodas and other soft drinks, instant breakfasts, breath mints, cereals, sugar-free chewing gum, cocoa mixes, frozen desserts, gelatin desserts, juices, laxatives, chewable vitamin supplements, milk drinks, pharmaceutical drugs and supplements, shake mixes, tabletop sweeteners, teas, instant coffees, topping mixes, wine coolers, and yogurt. It is provided as a table condiment in some countries. Aspartame is less suitable for baking than other sweeteners because it breaks down when heated and loses much of its sweetness.
The British soldiers were well positioned on the hillside and inflicted casualties on the Boers charging on horseback over a large distance, beating them back. This was the end of the war in the Western Transvaal and the last major battle of the war.
Initial research work was done by Alfred Champagnat at BP's Lavera Refinery in France; a small pilot plant there started operations in March 1963, and the same construction of the second pilot plant, at Grangemouth Oil Refinery in Britain, was authorized. The term SCP was coined in 1966 by Carroll L. Wilson of MIT. The "food from oil" idea became quite popular by the 1970s, with Champagnat being awarded the UNESCO Science Prize in 1976, and paraffin-fed yeast facilities being built in a number of countries. The primary use of the product was as poultry and cattle feed. The Soviets were particularly enthusiastic, opening large "BVK" (belkovo-vitaminny kontsentrat, i.e., "protein-vitamin concentrate") plants next to their oil refineries in Kstovo (1973) and Kirishi (1974). The Soviet Ministry of Microbiological Industry had eight plants of this kind by 1989. However, due to concerns of toxicity of alkanes in SCP and pressured by the environmentalist movements, the government decided to close them down, or convert to some other microbiological processes. Quorn is a range of vegetarian and vegan meat-substitutes made from Fusarium venenatum mycoprotein, sold in Europe and North America. Another type of single cell protein-based meat analogue (which does not use fungi however but rather bacteria) is Calysta. Other producers are Unibio (Denmark) Circe Biotechnologie (Austria) and String Bio (India). SCP has been argued to be a source of alternative or resilient food.
Sources: en.wikipedia.org
6'-deoxychalcone synthase (EC 2.3.1.170) is an enzyme that catalyzes the synthesis of the polyketide, isoliquiritigenin, from one unit of coumaroyl-CoA and three of malonyl-CoA. The enzyme requires reduced nicotinamide adenine dinucleotide phosphate (NADPH) to activate its substrate. It is present in Glycyrrhiza echinata (Russian licorice) and other leguminous plants, where it is part of the pathway to phytoalexins such as the flavanone, liquiritigenin.
=== Lymphatic drainage === Lymphatic channels from the posterior half of the scalp drain to occipital and posterior auricular nodes. Lymphatic channels from the anterior half drain to the parotid nodes. The lymph eventually reaches the submandibular and deep cervical nodes.
Abbott expanded the range of stores offering EAS products from niche stores such as GNC to mainstream stores such as Walmart and Target. In March 2011, Abbott laboratories removed the EAS brand from international markets and ceased European production of EAS products. This included the closing of the Canadian and UK country businesses and regional distribution in Europe, Australia, and New Zealand along. In August 2018, the brand was discontinued by Abbott Laboratories.
== Gene expression == This gene encodes a member of the peroxisome proliferator-activated receptor (PPAR) subfamily of nuclear receptors. PPARs form heterodimers with retinoid X receptors (RXRs) and these heterodimers regulate transcription of various genes. Three subtypes of PPARs are known: PPAR-alpha, PPAR-delta, and PPAR-gamma. The protein encoded by this gene is PPAR-gamma and is a regulator of adipocyte differentiation. Alternatively spliced transcript variants that encode different isoforms have been described. The activity of PPARG can be regulated via phosphorylation through the MEK/ERK pathway. This modification decreases transcriptional activity of PPARG and leads to diabetic gene modifications, and results in insulin insensitivity. For example, the phosphorylation of serine 112 will inhibit PPARG function, and enhance adipogenic potential of fibroblasts.
The adhesion of slug slime derived and inspired bioadhesives is achieved through four primary mechanisms: chemical bonding, mechanical interlocking, electrostatic interaction and crosslinking reactions. Slug/snail bioinspired hydrogel adhesive can be formed by covalently crosslinking snail polyanionic glycosaminoglycan and positively charged methacrylated gelatin polymers. Under UV exposure the combination of these two compounds undergoes gelation and solidifies. Proteins in the mucus create super molecular entanglement by creating a 3D network that interacts with the linear polysaccharides in the mucus. This entanglement is fortifies by electrostatic forces of attraction between positively charges amino groups in the protein and negatively charged sulfate and carboxyl groups in the polysaccharides. Hydrogen bonding also contributes to the formation of the hydrogel structure do to the presence of hydroxyl groups, aromatic and aliphatic amino acid in the mucus.
Sources: en.wikipedia.org
The amino acid sequence matches human growth hormone-releasing hormone, but the amino terminus carries a trans-3-hexenoyl group instead of a free amine. That single structural change chiefly affects enzymatic stability rather than receptor selectivity.
Growth hormone released from the pituitary stimulates IGF-1 production in the liver and other tissues, so circulating IGF-1 generally rises during exposure. The size of the rise varies between individuals and depends on baseline hormonal status and other concurrent factors.
Reported imaging studies focus on visceral adipose tissue, where reductions are more consistently observed across trials. Subcutaneous depots show smaller and less reproducible changes, so the two compartments should not be treated as equivalent.
It is a synthetic peptide built from 44 amino acids arranged in the same order as human growth hormone-releasing hormone. A short fatty-acid chain, described as a trans-3-hexenoyl group, is attached to the first amino acid. The finished molecule is formulated as a sterile powder that is dissolved before use.