Everything below concerns GHRH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Tesamorelin is a synthetic peptide that belongs to the growth hormone-releasing hormone (GHRH) family. Its sequence corresponds to the fully active 44-amino-acid form of human GHRH, with a single structural modification: the addition of a trans-3-hexenoyl group at the N-terminus. That modification is not found in the naturally occurring hormone and was introduced deliberately during development to improve stability against enzymatic degradation. The compound is therefore best described as a stabilized analogue rather than a naturally occurring peptide.
The native hormone is produced in the hypothalamus and acts on the anterior pituitary. Binding of GHRH to its receptor stimulates synthesis and release of growth hormone into circulation. Because the analogue retains the receptor-binding region of the parent sequence, it engages the same receptor and triggers the same downstream signaling. The result is increased growth hormone secretion from pituitary cells, which in turn influences hepatic production of insulin-like growth factor 1. This axis is the basis for the compound's measured biological effects.
纯度与身份确认依赖色谱与质谱的组合。反相高效液相色谱在 214 nm 紫外检测下分离主峰与相关杂质，给出纯度百分比与保留时间；电喷雾或基质辅助激光解吸电离质谱提供分子量，用于确认 N 端修饰是否完整。序列层面可通过肽图或氨基酸分析验证。含量测定常用紫外吸收法或氮元素分析，不同方法之间需要做交叉校验。
冻干粉末一般在 -20°C 或更低温度、干燥避光条件下保存，可维持较长时间的稳定。复溶后稳定性明显下降，溶液中的肽链易发生水解、氧化与聚集，通常需冷藏并在短期内用完。反复冻融会加速聚集与降解，建议分装后单次使用。缓冲体系的 pH 与离子强度同样影响聚集速率，需要按具体实验条件验证。
研究用与临床用材料的标准并不相同。质量控制通常覆盖纯度、残留溶剂、反离子含量、微生物限度与内毒素水平，各项均有对应检测方法。随货文件应包含批号、检测项目、方法与结果，使数据可以追溯。核验时应关注纯度是否按主峰面积计算、杂质是否已定性、方法是否经过验证，这些信息决定结果能否被外部重复。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C221H366N72O67S | Reflects a 44-residue peptide with one N-terminal modification |
| Approximate molecular weight | 5136 Da | Sequence length and single acyl group determine the mass |
| Appearance | White to off-white lyophilized powder | Typical form of a purified synthetic peptide |
| Solubility class | Soluble in water and aqueous buffer | Peptide backbone favors aqueous dissolution |
| Common synonyms | GHRH(1-44) analogue; Egrifta | Descriptive name and approved brand name |
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone, built from 44 amino acids. Its sequence follows the natural human GHRH(1-44) backbone, with a trans-3-hexenoyl group attached to the N-terminal tyrosine. This modification blocks recognition by dipeptidyl peptidase IV, the enzyme that rapidly truncates the native hormone in circulation. The result is a molecule with a substantially longer plasma residence time than unmodified GHRH, which makes it practical for clinical and laboratory study.
Receptor-level activity begins when the peptide binds the GHRH receptor, a class B G-protein-coupled receptor found on pituitary somatotroph cells. Occupancy triggers Gs-mediated activation of adenylyl cyclase and a rise in intracellular cyclic AMP, which in turn promotes synthesis and pulsatile release of growth hormone. Because the compound acts upstream of the growth hormone axis rather than supplying hormone directly, its effect depends on intact pituitary function. Binding studies in cell culture and animal models have established this pathway; the detailed kinetics of receptor recycling in humans remain less well characterized.
Lyophilized material is typically held under refrigeration between two and eight degrees Celsius, shielded from light and ambient moisture. Peptides of this size adsorb to glass and plastic, so working procedures often call for low-binding containers and as few transfers as possible. Absorbed water during weighing shifts the apparent mass of a sample, and controlling room humidity reduces that source of error. Once dissolved, solutions are kept cold and used within the interval printed on the accompanying label or certificate. Degradation accelerates markedly in dilute aqueous form.
Identity and purity are judged through a combination of chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the intact peptide from truncated, oxidized, and deamidated variants, and the resulting peak-area percentages yield a purity figure. Electrospray ionization mass spectrometry confirms the expected molecular mass and can expose unanticipated modifications. Amino acid analysis and peptide mapping support sequence fidelity, while water content, pH, sterility, and bacterial endotoxin testing describe the physical and microbiological attributes of a finished lot.
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone, composed of 44 amino acids. It was designed to retain the biological activity of the native hormone while resisting rapid enzymatic degradation. The compound is classified as a growth hormone secretagogue and belongs to the broader family of hypothalamic releasing factors. In research and clinical settings, it is studied for its ability to stimulate pituitary growth hormone release. Its structure includes a modification at the N-terminus that contributes to an extended half-life relative to native growth hormone-releasing hormone.
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.
Growth hormone released from the pituitary stimulates the liver and other tissues to produce insulin-like growth factor 1, a stable circulating protein that serves as a practical marker of activity. Clinical studies therefore track IGF-1 concentrations alongside the hormone itself, and they commonly measure body composition with imaging rather than relying on body weight alone. Visceral adipose tissue, the fat surrounding abdominal organs, is quantified by computed tomography in the studies that supported approval. Adverse effects reported in trials include injection-site reactions, joint pain, and increases in blood glucose, which is why monitoring accompanies use.
Questions remain about how much of the observed fat reduction reflects direct GHRH-receptor signaling versus the downstream growth hormone and IGF-1 surge. It is also unclear whether the compound produces meaningful benefit in populations without lipodystrophy, since trials in cognitive impairment did not reach their stated goals. Long-term effects on glucose metabolism and on cardiovascular outcomes are not fully characterized. Published work generally describes effects on surrogate markers rather than on hard clinical endpoints, and independent replication of some findings is limited.
In order to overcome the insufficient prediction of binding affinity calculated by recent scoring functions, the protein-ligand interaction and compound 3D structure information are used for analysis. For structure-based drug design, several post-screening analyses focusing on protein-ligand interaction have been developed for improving enrichment and effectively mining potential candidates:
In the 1950s, Alfred Nier developed the technique of ID-TIMS, which later become the first tool used in monazite geochronology. Since this method involves the chemical separation of monazite (isotope dilution), it is regarded as a conventional analysis technique. Generally, it takes several hours for a U-Pb measurement. The precision of date is nearly 0.1%, provided that the ages are concordant (i.e. not dates reflecting mixing of zonations). It is regarded as the most precise method in monazite geochronology. Monazite mineral grains are carefully hand-picked for dating. They are spiked with a tracer solution and dissolved in HF or HCl. Using ion exchange chemistry, U, Th and Pb are separated from other elements. The purposes of the separation are (1) potential isobaric interference should be removed before analysis because of the high-sensitivity and low-mass resolution nature of TIMS; (2) ionization of the elements of interest maybe impeded by other elements, which results in reduced signal size and precision. The separated U, Th and Pb samples are put carefully onto a metal filament, which is usually made from Re. The elements are heated and ionize to their respective ions, which are accelerated under a strong magnetic field and are measured by a detector. The tracer solution is a solution with a known amount of U and Pb tracer isotopes. Due to elemental fractionation, both elements cannot be measured simultaneously by TIMS. The tracer solution is therefore used to measure ratios of sample isotope to tracer isotopes.
== Medical use == A 2018 Cochrane review found that fluphenazine was an imperfect treatment and other inexpensive drugs less associated with side effects may be an equally effective choice for people with schizophrenia. Another 2018 Cochrane review found that there was limited evidence that newer atypical antipsychotics were more tolerable than fluphenazine. Intramuscular depot injection forms are available as both the decanoate and enanthate esters.
Sources: en.wikipedia.org
Nanoparticles made from natural polymers that are biodegradable have the abilities to target specific organs and tissues in the body, to carry DNA for gene therapy, and to deliver larger molecules such as proteins, peptides, and even genes. To manufacture these polymeric nanoparticles, the drug molecules are first dissolved and then encapsulated or attached to a polymer nanoparticle matrix. Three different structures can then be obtained from this process; nanoparticles, nanocapsules (in which the drug is encapsulated and surrounded by the polymer matrix), and nanospheres (in which the drug is dispersed throughout the polymeric matrix in a spherical form). One of the most important traits for nanoparticle delivery systems is that they must be biodegradable on the scale of a few days. A few common polymer materials used for drug delivery studies are polybutyl cyanoacrylate (PBCA), poly(isohexyl cyanoacrylate) (PIHCA), polylactic acid (PLA), or polylactide-co-glycolide (PLGA). Human serum albumin (HSA) and chitosan are also materials of interest. PBCA undergoes degradation through enzymatic cleavage of its ester bond on the alkyl side chain to produce water-soluble byproducts. PBCA also proves to be the fastest biodegradable material, with studies showing 80% reduction after 24 hours post intravenous therapy injection. PIHCA, however, was recently found to display an even lower degradation rate, which in turn further decreases toxicity.
ABRF Next Generation Sequencing Group (ABRF-NGS) Antibody Technology Research Group (ARG) Biomedical 'Omics Research Group (BORG) DNA Sequencing Research Group (DSRG) Flow Cytometry Research Group (FCRG) Genomics Research Group (GVRG) Glycoprotein Research Group (gPRG) Light Microscopy Research Group (LMRG) Metabolomics Research Group (MRG) Metagenomics Research Group (MGRG) Molecular Interactions Research Group (MIRG) Nucleic Acids Research Group (NARG) Protein Expression Research Group (PERG) Protein Sequencing Research Group (PSRG) Proteomics Research Group (PRG) Proteome Informatics Research Group (iPRG) Proteomics Standards Research Group (sPRG)
CRF, produced in the PVN, activates CRF1 receptors and CRF2 receptors distributed across limbic circuits. CRF1 receptor activation, which mediates rapid and intense stress responses, triggers acute dynorphin release in limbic stress-responsive regions including the NAcc, basolateral amygdala, dorsal raphe nucleus (DRN), hippocampus, and bed nucleus of the stria terminalis (BNST). CRF2 receptor activation, generally associated with slower, later-phase stress response components, also induces dynorphin-dependent aversive responses such as conditioned place aversion (CPA). Subsequently dynorphin activates KORs expressed on GABAergic and dopaminergic neurons, encoding the aversive and dysphoric qualities of stress exposure. Acutely stress-induced dynorphin release and KOR activation have evolutionarily adaptive functions. KOR-mediated analgesia facilitates physical escape responses to threat, and concurrent KOR-induced dysphoria and aversion promote avoidance and active coping. However, during the delayed temporal phase following acute stress exposure (hours to days), stress-induced KOR signaling initiates intracellular signaling cascades including p38 MAPK and extracellular signal-regulated kinases (ERK) which phosphorylate transcription factors such as cAMP response element-binding protein (CREB) and alter dynorphin and KOR gene expression itself, establishing a self-amplifying cycle.
Sources: en.wikipedia.org
Wound dehiscence is a surgical complication in which a wound ruptures along a surgical incision. Risk factors include age, collagen disorder such as Ehlers–Danlos syndrome, diabetes, obesity, poor knotting or grabbing of stitches, and trauma to the wound after surgery.
Placing a wedge in the felling cut can prevent a sitback from pinching the saw. Freeing: Working a badly fallen tree that may have become trapped in other trees. Working out maximum tension locations to decide the safest way to release tension, and a winch may be needed in complicated situations. To avoid cutting straight through a tree in tension, one or two cuts at the tension point of sufficient depth to reduce tension may be necessary. After tension releases, cuts are made outside the bend. Limbing: Cutting the branches off the log. The operator must be able to properly reach the cut to avoid kickback. Bucking: Cross-cutting the felled log into sections. Setup is made to avoid binding the chainsaw within the changing log tensions and compressions. Safe bucking is started at the log high-side and then sections worked offside, toward the butt end. The offside log falls and allows for gravity to help prevent binds. The log's kerf movement while cutting can help to indicate binds. Additional equipment (lifts, bars, wedges, and winches) and special cutting techniques can help prevent binds. Binds: This is when the chainsaw is at risk or is stuck in the log compression. A log bound chainsaw is unsafe and must be carefully removed to prevent equipment damage. Top bind – The tension area on log bottom, compression on top. Bottom bind – The tension area on log top, compression on bottom. Side bind – Sideways pressure exerted on the log. End bind – Weight compresses the log's entire cross-section.
Ornithology (from Ancient Greek ὄρνις (órnis) 'bird' and λόγος (lógos) 'study of') is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds. It has also been an area with a large contribution made by amateurs in terms of time, resources, and financial support. Studies on birds have helped develop key concepts in biology including evolution, behaviour and ecology such as the definition of species, the process of speciation, instinct, learning, ecological niches, guilds, insular biogeography, phylogeography, and conservation. While early ornithology was principally concerned with descriptions and distributions of species, ornithologists today seek answers to very specific questions, often using birds as models to test hypotheses or predictions based on theories. Most modern biological theories apply across life forms, and the number of scientists who identify themselves as ornithologists has therefore declined. A wide range of tools and techniques are used in ornithology, both inside the laboratory and out in the field, and innovations are constantly made. Most biologists who recognise themselves as ornithologists study specific biology research areas, such as anatomy, physiology, taxonomy (phylogenetics), ecology, or behaviour.
Sources: en.wikipedia.org
It shares the 44-residue sequence of human GHRH but carries an added trans-3-hexenoyl group at its N-terminus. That addition does not occur in the natural hormone and serves mainly to resist enzymatic breakdown. The receptor target and signaling pathway remain the same.
It binds the growth hormone-releasing hormone receptor on anterior pituitary cells. Activation of that receptor promotes synthesis and release of growth hormone. The effect propagates through the growth hormone and insulin-like growth factor 1 axis.
Native GHRH is cleared quickly by peptidases, which limits how long it can stimulate its receptor. The added group hinders one of the primary cleavage enzymes. The practical consequence is a longer period of receptor activity per dose.
多肽在反相柱上按疏水性差异分离，能有效区分主峰、缺失序列片段与氧化产物。配合紫外检测可获得可量化的纯度百分比，是肽类分析的常规手段。