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Clinical interest in tesamorelin arose from the need to address visceral adiposity in people living with HIV. Antiretroviral therapy improved survival but was associated in some patients with central fat accumulation, altered lipid profiles, and metabolic complications. This condition, often called HIV-associated lipodystrophy, involves excess visceral adipose tissue that is difficult to manage through diet and exercise alone. Investigators evaluated tesamorelin because GHRH analogs can stimulate growth hormone secretion and influence fat distribution without direct liposuction or invasive procedures.
A Phase 3 program led to regulatory approval in the United States in 2010 for reduction of excess visceral abdominal fat in adults with HIV and lipodystrophy. Subsequent studies examined effects on liver fat, muscle area, and metabolic markers, with mixed findings for some endpoints. Long-term cardiovascular outcomes and effects on mortality remain uncertain because most trials were relatively short and focused on imaging-based fat measurements. Use in populations without HIV has been studied experimentally but is not part of the approved indication.
Tesamorelin acts on the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in intracellular cyclic AMP, which in turn opens ion channels and raises calcium concentrations, leading to release of stored growth hormone into the bloodstream. Because the peptide works through the same receptor as the body's own GHRH, the resulting secretion follows a pulsatile pattern rather than a continuous elevation. The N-terminal modification slows enzymatic breakdown, so the signal persists longer than it would with the unmodified hormone.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | Approximately 5,136 Da | Based on the 44-amino-acid peptide backbone and N-terminal modification. |
| Appearance | White to off-white lyophilized powder | Usually supplied in single-use vials for reconstitution. |
| Solubility | Freely soluble in water; slightly soluble in some organic solvents | Peptide nature supports aqueous reconstitution. |
| Typical storage | 2–8 °C, protected from light | Refrigeration reduces degradation; avoid freezing unless specified. |
| Common analytical method | Reverse-phase high-performance liquid chromatography | Used for identity, purity, and quantification. |
| Synonyms | Tesamorelin, TH9507, GHRH(1-44) analog | Generic descriptors; avoid proprietary names. |
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.
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.
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.
Regulatory position depends on jurisdiction and on the form in which the material is sold. A branded product holds approval in the United States for a defined indication, and prescribing is confined to that label. Material marketed for laboratory research is not evaluated for human use and carries no such clearance. Independent verification therefore rests on certificates of analysis, third-party testing, and documented chain of custody. The substance also appears on the World Anti-Doping Agency prohibited list within the category covering growth hormone-releasing factors.
Physicochemical behavior is dominated by the peptide backbone. The molecule is hydrophilic and carries a net positive charge near neutral pH, owing to several arginine and lysine residues. In solution it adopts a largely unstructured conformation, and aggregation is a known concern for peptide products of this size. Oxidation of methionine and deamidation of asparagine or glutamine residues are the principal chemical degradation routes. These liabilities shape how the material is formulated, handled, and analyzed, and they explain why lyophilized presentations are common in research settings.
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.
=== Red blood cell production === Erythropoietin is an essential hormone for red blood cell production. Without it, definitive erythropoiesis does not take place. Under hypoxic conditions, the kidney will produce and secrete erythropoietin to increase the production of red blood cells by targeting CFU-E, proerythroblast and basophilic erythroblast subsets in the differentiation. Erythropoietin has its primary effect on red blood cell progenitors and precursors (which are found in the bone marrow in humans) by promoting their survival through protecting these cells from apoptosis, or cell death. Erythropoietin is the primary erythropoietic factor that cooperates with various other growth factors (e.g., IL-3, IL-6, glucocorticoids, and SCF) involved in the development of erythroid lineage from multipotent progenitors. The burst-forming unit-erythroid (BFU-E) cells start erythropoietin receptor expression and are sensitive to erythropoietin. Subsequent stage, the colony-forming unit-erythroid (CFU-E), expresses maximal erythropoietin receptor density and is completely dependent on erythropoietin for further differentiation. Precursors of red cells, the proerythroblasts and basophilic erythroblasts also express erythropoietin receptor and are therefore affected by it.
Casein is amphiphilic and therefore can be used as an emulsifier. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive. The most common form of casein is sodium caseinate (historically called nutrose), which is a very efficient emulsifier. Casein is secreted into milk from mammary cells in the form of colloidal casein micelles, a type of biomolecular condensate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphorus. While in animals it is only made by mammilian mammary glands (unlike some whey proteins), casein has been artificially biosynthesized. Animal-free casein proteins have been produced since at least the early 1990's using bacteria-based recombinant DNA precision fermentation genetic engineering, and has been in the process of commercialization by cellular agriculture for more than a decade. Plant-produced beta-casein has been synthesized at least since 2026.
== Limitations == One major limitation of PCR is that prior information about the target sequence is necessary in order to generate the primers that will allow its selective amplification. This means that, typically, PCR users must know the precise sequence(s) upstream of the target region on each of the two single-stranded templates in order to ensure that the DNA polymerase properly binds to the primer-template hybrids and subsequently generates the entire target region during DNA synthesis. The limitation is offset when using arbitrarily amplified DNA techniques such as DNA amplification fingerprinting (DAF) or randomly amplification of polymorphic DNA (RAPD). These DNA profiling methods use arbitrary primers in PCR reactions that do not require sequence knowledge. Like all enzymes, DNA polymerases are also prone to error, which in turn causes mutations in the PCR fragments that are generated. Another limitation of PCR is that even the smallest amount of contaminating DNA can be amplified, resulting in misleading or ambiguous results. To minimize the chance of contamination, investigators should reserve separate rooms for reagent preparation, the PCR, and analysis of product. Reagents should be dispensed into single-use aliquots. Pipettors with disposable plungers and extra-long pipette tips should be routinely used. It is moreover recommended to ensure that the lab set-up follows a unidirectional workflow. No materials or reagents used in the PCR and analysis rooms should ever be taken into the PCR preparation room without thorough decontamination.
Sources: en.wikipedia.org
=== Right lung === The right lung has both more lobes and segments than the left. It is divided into three lobes, an upper, middle, and a lower lobe by two fissures, one oblique and one horizontal. The upper, horizontal fissure, separates the upper from the middle lobe. It begins in the lower oblique fissure near the posterior border of the lung, and, running horizontally forward, cuts the anterior border on a level with the sternal end of the fourth costal cartilage; on the mediastinal surface it may be traced back to the hilum. The lower, oblique fissure, separates the lower from the middle and upper lobes and is closely aligned with the oblique fissure in the left lung. The mediastinal surface of the right lung is indented by a number of nearby structures. The heart sits in an impression called the cardiac impression. Above the hilum of the lung is an arched groove for the azygos vein, and above this is a wide groove for the superior vena cava and right brachiocephalic vein; behind this, and close to the top of the lung is a groove for the brachiocephalic artery. There is a groove for the oesophagus behind the hilum and the pulmonary ligament, and near the lower part of the oesophageal groove is a deeper groove for the inferior vena cava before it enters the heart. The weight of the right lung varies between individuals, with a standard reference range in men of 155–720 g (0.342–1.587 lb) and in women of 100–590 g (0.22–1.30 lb).
A win on the final day against Newcastle United secured fourth position, which Wenger described as a "relief". Arsenal opened the 2013–14 season with a home defeat to Aston Villa, which prompted boos from the supporters. The club's transfer inactivity over the summer was criticised, but Wenger assessed: "We could have won the game today with the players on the pitch, I'm convinced of that." In the final week of the transfer window, he re-signed Flamini and sanctioned the club record signing of Mesut Özil from Real Madrid, totalling £42.5 million. Wenger was instrumental in the latter deal; he phoned and spoke to the German in his native language, convincing him that a move to England would enhance his career. Arsenal's form thereafter improved and Aaron Ramsey's goalscoring spree elevated the team to first position by the New Year. Poor performances in the big games, however, blighted Arsenal's title credentials, with a 6–0 loss to Chelsea at Stamford Bridge being described as "a good hiding [as] you don't prepare all week to experience that." The defeat marked Wenger's 1,000th match in charge of Arsenal. Arsenal consolidated fourth position in the league, and Wenger guided his team to FA Cup success, as they came from two goals down to beat Hull City in the final, and clinch Arsenal their first trophy in nine years. At the end of the season, Wenger signed another three-year extension to his Arsenal contract.
Ningxia, officially the Ningxia Hui Autonomous Region (NHAR), is an autonomous region in Northwestern China. Formerly a province, Ningxia was incorporated into Gansu in 1954 but was later separated from Gansu in 1958 and reconstituted as an autonomous region for the Hui people, one of the 56 officially recognised ethnicities in China. Twenty percent of China's Hui population lives in Ningxia. Ningxia is bounded by Shaanxi to the east, Gansu to the south and west and Inner Mongolia Autonomous Region to the north and has an area of around 66,400 square kilometres (25,600 sq mi). This sparsely settled, mostly desert region lies partially on the Loess Plateau and in the vast plain of the Yellow River and features the Great Wall of China along its northeastern boundary. Over about 2000 years, an extensive system of canals (with a total length of approximately 1397 kilometers) has been built since the Qin dynasty. Extensive land reclamation and irrigation projects have made increased cultivation possible. The arid region of Xihaigu, which covers large parts of the province, suffers from severe water shortage, which the canals were intended to alleviate. Ningxia was the core area of the Western Xia in the 11th–13th centuries, established by the Tangut people; its name, "Peaceful Xia", derived from the Mongol conquest of the state. The Tanguts made significant achievements in literature, art, music, and architecture, and in particular, invented Tangut script. Long one of the country's poorest areas, a small winemaking industry has become economically important since the 1980s.
Sources: en.wikipedia.org
== Etymology == The name mercapturic acid is a combination of mercapturic and acid. The latter indicates that the compound is an acid. The former is a compound word consisting of the stem mercaptur-, coming from mercaptan, and the suffix -ic, meaning "having the character of". In sum, the name mercapturic acid means "an acid with mercaptan character/nature".
Over 2000 compounds were tested randomly in a guinea pig ileum test and succinyl-L-proline was found to have the properties of a specific ACE inhibitor. It showed inhibitory effect of angiotensin I and bradykinin without having any effects on angiotensin II. Then researchers started to search for a model that would explain inhibition on the basis of specific drug interactions of compounds with the active site of ACE. Previous studies with substrates and inhibitors of ACE suggested that it was a zinc-containing metalloprotein and a carboxypeptidase similar to pancreatic carboxypeptidase A. However ACE releases dipeptides rather than single amino acids from the C-terminus of the peptide substrates. And it was assumed that both their mechanism of action and their active site might be similar. A positively charged Arg145 at the active site was thought to bind with the negatively charged C-terminal carboxyl group of the peptide substrate. It was also proposed that ACE binds by hydrogen bonding to the terminal, non scissile, peptide bond of the substrate. But since ACE is a dipeptide carboxypeptidase, unlike carboxypeptidase A, the distance between the cationic carboxyl-binding site and the zinc atom should be greater, by approximately the length of one amino acid residue. Proline was chosen as the amino acid moiety because of its presence as the carboxy terminal amino acid residue in teprotide and other ACE inhibitors found in snake venoms. Eleven other amino acids were tested but none of them were more inhibitory.
== Basic principle == In conventional affinity chromatography, a single chromatography column is loaded with feed material up to the point before target material (product) cannot be retained by the affinity material anymore. The resin with the adsorbed product on it is then washed to remove impurities. Finally, the pure product is eluted with a different buffer. Notably, if too much feed material is loaded onto the column, the product can break through and product is consequently lost. Therefore, it is very important to only partially load the column to maximize the yield.
== Clinical significance == A mutation in the tyrosinase gene resulting in impaired tyrosinase production leads to type I oculocutaneous albinism, a hereditary disorder that affects one in every 20,000 people. Tyrosinase activity is very important. If uncontrolled during the synthesis of melanin, it results in increased melanin synthesis. Decreasing tyrosinase activity has been targeted for the improvement or prevention of conditions related to the hyperpigmentation of the skin, such as melasma and age spots. Several polyphenols, including flavonoids or stilbenoid, substrate analogues, free radical scavengers, and copper chelators, have been known to inhibit tyrosinase. Henceforth, the medical and cosmetic industries are focusing research on tyrosinase inhibitors to treat skin disorders.
Sources: en.wikipedia.org
It is a synthetic peptide analog of human growth hormone-releasing hormone. It is used clinically to reduce excess visceral abdominal fat in adults with HIV-associated lipodystrophy. It works by stimulating pituitary growth hormone release.
Pivotal trials enrolled adults with HIV and excess visceral abdominal fat, often in the context of antiretroviral therapy. Participants were assessed mainly by computed tomography for visceral adipose tissue. The approved indication remains specific to that population.
Long-term effects on cardiovascular events, mortality, and sustained fat distribution are not well established. Most trials measured changes over months rather than years. Open questions also include whether benefits persist after treatment stops.
It acts upstream at the pituitary receptor and depends on functioning somatotroph cells to produce any effect. Growth hormone injections bypass that step and deliver the hormone directly. The pharmacokinetic profiles and the resulting feedback on the body's own secretion therefore differ.