IGF-1 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-11-20 and is reviewed periodically as new material appears.
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.
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。
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。
| 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。
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.
Lurasidone [(3aR,4S,7R,7aS)-2-{(1R,2R)-2-[4-(1,2-benzisothiazol-3-yl) piperazin-1-ylmethyl]-cyclohexylmethyl}-hexahydro-4,7-methano-2Hisoindole-1,3-dione hydrochloride] ] is an azapirone derivative and acts as an antagonist of the dopamine D2 and D3 receptors, and the serotonin 5-HT2A and 5-HT7 receptors, and the α2C-adrenergic receptor, and as a partial agonist of the serotonin 5-HT1A receptor. It has moderate-affinity antagonism at α2C-adrenergic receptors; low to very low-affinity antagonism at α1A-adrenergic α2A-adrenergic receptors. It has only low and likely clinically unimportant affinity for the serotonin 5-HT2C receptor, which may underlie its low propensity for appetite stimulation and weight gain. The drug also has negligible affinity for the histamine H1 receptor and the muscarinic acetylcholine receptors, and hence has no antihistamine or anticholinergic effects. Drowsiness (somnolence) side effect is not explained by its antagonist activity to histamine. The relationship between dose and D2 receptor occupancy levels were 41–43% for 10 mg, 51–55% for 20 mg, 63–67% for 40 mg, 77–84% for 60 mg, and 73–79% for 80 mg.
== ATP analogues == Biochemistry laboratories often use in vitro studies to explore ATP-dependent molecular processes. ATP analogs are also used in X-ray crystallography to determine a protein structure in complex with ATP, often together with other substrates. Enzyme inhibitors of ATP-dependent enzymes such as kinases are needed to examine the binding sites and transition states involved in ATP-dependent reactions. Most useful ATP analogs cannot be hydrolyzed as ATP would be; instead, they trap the enzyme in a structure closely related to the ATP-bound state. Adenosine 5′-(γ-thiotriphosphate) is an extremely common ATP analog in which one of the gamma-phosphate oxygens is replaced by a sulfur atom; this anion is hydrolyzed at a dramatically slower rate than ATP itself and functions as an inhibitor of ATP-dependent processes. In crystallographic studies, hydrolysis transition states are modeled by the bound vanadate ion. Caution is warranted in interpreting the results of experiments using ATP analogs, since some enzymes can hydrolyze them at appreciable rates at high concentration.
The law of conservation of vis viva was championed by the father and son duo, Johann and Daniel Bernoulli. The former enunciated the principle of virtual work as used in statics in its full generality in 1715, while the latter based his Hydrodynamica, published in 1738, on this single vis viva conservation principle. Daniel's study of loss of vis viva of flowing water led him to formulate Bernoulli's principle, which asserts the loss to be proportional to the change in hydrodynamic pressure. Daniel also formulated the notion of work and efficiency for hydraulic machines; and he gave a kinetic theory of gases, and linked the kinetic energy of gas molecules with the temperature of the gas. This focus on the vis viva by the continental physicists eventually led to the discovery of stationarity principles governing mechanics, such as the D'Alembert's principle, Lagrangian, and Hamiltonian formulations of mechanics.
A later vertebrate study identified protein tyrosine phosphatase receptor F (PTPRF), a member of the LAR family, as a conserved cognate receptor for the glucogenic actions of asprosin. In zebrafish, two Ptprf paralogs (ptprfa/b) are expressed in liver, bind asprosin with nanomolar affinity, and are required for asprosin-induced hyperglycemia and upregulation of gluconeogenic genes; soluble Ptprf ligand-binding domains neutralize the glucogenic effects and lower basal glucose, while ptprfa/b knockout fish show hypoglycemia and a blunted response to asprosin but normal responses to glucagon. In mice, PTPRF is expressed in liver and binds asprosin; Ptprf-deficient animals exhibit impaired asprosin-induced glucose production and reduced hepatic G6pc and Pck1 induction, and Ptprf deletion improves glucose tolerance without altering Olfr734 expression. Mechanistically, the same study showed that asprosin promotes insulin receptor and Akt dephosphorylation via PTPRF, counteracting insulin's suppression of gluconeogenesis and suggesting that chronic asprosin–PTPRF signaling contributes to hepatic insulin resistance. Several other independent studies have confirmed asprosin's glucogenic function.
=== Paramilitaries and other sources of income === Beyond drug trafficking, Mexican cartels derive revenue from activities including extortion, kidnapping, oil theft from pipelines, human smuggling, illegal mining and logging, arms trafficking, sex trafficking, and protection rackets in territories under their control. The fragmentation of larger cartels into regional groups has extended their operations beyond traditional strongholds in Michoacán, Guerrero, and Northern Mexico, with organized crime now present in nearly every Mexican state. Paramilitary groups work alongside cartels to enforce these activities. It has been suggested that the rise in paramilitary groups coincides with a loss of security within the government. These paramilitary groups came about in a number of ways. First, waves of elite armed forces and government security experts have left the government to join the side of the cartels, responding to large bribes. Some of the elite armed forces members who join paramilitaries are trained in the Western Hemisphere Institute for Security Cooperation (WHINSEC, formerly known as the School of the Americas). One theory suggests that paramilitaries have emerged from the deregulation of the Mexican army, which private security firms have gradually replaced.
Sources: en.wikipedia.org
=== Y-axis and relative abundance === Signal intensity may be dependent on many factors, especially the nature of the molecules being analyzed and how they ionize. The efficiency of ionization varies from molecule to molecule and from ion source to ion source. For example, in electrospray sources in positive ion mode a quaternary amine will ionize exceptionally well whereas a large hydrophobic alcohol will most likely not be seen no matter how concentrated. In an EI source these molecules will behave very differently. Additionally there may be factors that affect ion transmission disproportionally between ionization and detection. On the detection side there are many factors that can also affect signal intensity in a non-proportional way. The size of the ion will affect the velocity of impact and with certain detectors the velocity is proportional to the signal output. In other detection systems, such as FTICR, the number of charges on the ion are more important to signal intensity. In Fourier transform ion cyclotron resonance and Orbitrap type mass spectrometers the signal intensity (Y-axis) is related to the amplitude of the free induction decay signal. This is fundamentally a power relationship (amplitude squared) but often computed as an [rms]. For decaying signals the rms is not equal to the average amplitude. Additionally the damping constant (decay rate of the signal in the fid) is not the same for all ions. In order to make conclusions about relative intensity a great deal of knowledge and care is required.
== Packaging == Passive barrier packaging can often help control or extend shelf life by blocking the transmission of deleterious substances, like moisture or oxygen, across the barrier. Active packaging, on the other hand, employs the use of substances that scavenge, capture, or otherwise render harmless deleterious substances. When moisture content is a mechanism for product degradation, packaging with a low moisture vapor transmission rate and the use of desiccants help keep the moisture in the package within acceptable limits. When oxidation is the primary concern, packaging with a low oxygen transmission rate and the use of oxygen absorbers can help extend the shelf life. Produce and other products with respiration often require packaging with controlled barrier properties. The use of a modified atmosphere in the package can extend the shelf life for some products.
In 2023, the most opioid overdose deaths were among White Americans (47,754), followed by African Americans (16,481), Latinos (11,310), Native Americans (1,170), and Asians (695). While media attention has often focused on the uptick of deaths among middle class White Americans, the heroin overdose death rate among African Americans has gone up more than 200 percent since 2010. Among Latinos, it climbed nearly 140 percent. The prevalence of rural opioid overdose deaths per 100,000 within the USA was highest for Native Americans, followed by non-Hispanic Whites, Black, Hispanic, and Asian/Pacific Islander individuals. During the first and second wave of the opioid epidemic, White American people were most affected by opioid overdose. While all groups were affected in the third and fourth wave of the epidemic, White Americans and non-Hispanic Black individuals saw the greatest rise in deaths. Native Americans and Alaska Natives experienced a five-fold increase in opioid-overdose deaths between 1999 and 2015, with Native Americans having the highest increase of any demographic group. With the belief that there would be a low risk of addiction, Indian Health Service physicians, like doctors nationwide, readily prescribed opioids. In addition, structural health care deficiencies from the provider and cultural beliefs against receiving care from the patient, as well as inadequate community support structures for substance misuse, contributed to high mortality rates. In 2015, American Indians/Alaska Natives had the greatest drug overdose mortality rates of any U.S.
Sericin is a protein created by Bombyx mori (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% fibroin and 20–30% sericin; fibroin being the structural center of the silk, and sericin being the gum coating the fibres and allowing them to stick to each other.
Sources: en.wikipedia.org
Camille Étienne, born 29 May 1998 in Grenoble, Auvergne-Rhone-Alpes, is a French environmental activist. A member of the duo Avant l'orage (Before the Storm), along with director Solal Moisan, she takes part in and leads acts of civil disobedience, lobbying of political and economic decision makers and raising public awareness.
== Mechanisms of Algicidal Bacteria == Various mechanisms are employed by bacteria to facilitate their algicidal processes. There are two established methods of algicidal activity: direct and indirect. However, some bacteria are capable of both. Some of these mechanisms are enhanced under different environmental conditions, such as varying nutrient availability.
== Treatment == The most common treatment for SCID is bone marrow transplantation, which has been very successful using either a matched related or unrelated donor, or a half-matched donor, who would be either parent. The half-matched type of transplant is called haploidentical. Haploidentical bone marrow transplants require the donor marrow to be depleted of all mature T cells to avoid the occurrence of graft-versus-host disease (GVHD). Consequently, a functional immune system takes longer to develop in a patient who receives a haploidentical bone marrow transplant compared to a patient receiving a matched transplant. The first reported case of successful transplant was a Spanish child patient who was interned in Memorial Sloan Kettering Cancer Center in 1982, in New York City. David Vetter, the original "bubble boy", had one of the first transplantations also, but eventually died because of an unscreened virus, Epstein-Barr (tests were not available at the time), in his newly transplanted bone marrow from his sister, an unmatched bone marrow donor. Today, transplants done in the first three months of life have a high success rate. Physicians have also had some success with in utero transplants done before the child is born and also by using cord blood which is rich in stem cells. In utero transplants allow for the fetus to develop a functional immune system in the sterile environment of the uterus; however complications such as GVHD would be difficult to detect or treat if they were to occur.
== Definitions == The words diaphoresis and hidrosis can both mean either perspiration (in which sense they are synonymous with sweating) or excessive perspiration (in which sense they can be either synonymous with hyperhidrosis or differentiable from it only by clinical criteria involved in narrow specialist senses of the words). Hypohidrosis is decreased sweating from whatever cause. Hyperhidrosis is excessive sweating, usually secondary to an underlying condition (in which case it is called secondary hyperhidrosis) and usually involving the body as a whole (in which case it is called generalized hyperhidrosis). Focal hyperhidrosis is increased or excessive sweating in certain regions such as the underarm, palms, soles, face, or groin. Hidromeiosis is a reduction in sweating that is due to blockages of sweat glands in humid conditions. A substance or medicine that causes perspiration is a sudorific or sudatory.
=== Among snakes === The question whether individual snakes are immune to their own venom has not yet been definitively settled, though an example is known of a cobra that self-envenomated, resulting in a large abscess requiring surgical intervention, but showing none of the other effects that would have proven rapidly lethal in prey species or humans. Furthermore, certain harmless species, such as the North American common kingsnake (Lampropeltis getula) and the Central and South American mussurana (Clelia spp.), are proof against the venom of the crotalines, which frequent the same districts, and which they are able to overpower and feed upon. The chicken snake (Spilotes pullatus) is the enemy of the fer-de-lance (Bothrops caribbaeus) in St. Lucia, and in their encounters, the chicken snake is invariably the victor. Repeated experiments have shown the European grass snake (Natrix natrix) not to be affected by the bite of the European adder (Vipera berus) and the European asp (Vipera aspis), this being due to the presence, in the blood of the harmless snake, of toxic principles secreted by the parotid and labial glands, and analogous to those of the venom of these vipers. Several North American species of rat snakes, as well as king snakes, have proven to be immune or highly resistant to the venom of rattlesnake species. The king cobra, which does prey on cobras, is said to be immune to their venom.
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.
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。