This is a working overview of Insulin-like growth factor 1, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
Whether the drug improves hard clinical outcomes is not settled. No completed trial has shown a reduction in heart attacks or strokes among treated patients, although a dedicated cardiovascular outcomes study has been discussed in the literature. Investigators have also examined hepatic fat in people with HIV and fatty liver disease, cognitive measures in small cohorts, and changes in bone density. Regulatory labeling emphasizes monitoring of insulin-like growth factor 1 because supraphysiologic levels raise questions about tissue growth, and the clinical significance of that signal remains an open question rather than a demonstrated harm.
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.
Identity and purity are assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass and detects chemical modifications. Peptide mapping and amino acid analysis can verify sequence integrity. Water content is measured by Karl Fischer titration, and residual solvents may be checked by gas chromatography. These methods together support batch-to-batch consistency and routine quality control.
Lyophilized tesamorelin is generally stored refrigerated at temperatures between 2 and 8 degrees Celsius. The solid form is comparatively stable when kept dry and protected from light. Moisture uptake can promote aggregation and degradation, so sealed containers with desiccant are common. Researchers typically avoid repeated temperature cycling, which may stress the peptide. Documentation accompanying reference materials usually specifies a shelf life under these conditions.
Once reconstituted, the peptide is handled as a solution and is less stable than the lyophilized powder. Aqueous solutions are commonly kept cold and used within a defined period. Buffer composition and pH influence degradation rates, with extremes of acidity or alkalinity accelerating hydrolysis. Preservatives may be added in multi-dose formats to limit microbial growth. Freezing and thawing of solutions is generally avoided because it can cause precipitation or loss of activity.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized cake in single-use vials |
| Solubility class | Freely soluble in water | Reconstituted with sterile diluent before injection |
| Typical storage temperature | 2 to 8 degrees Celsius | Before reconstitution; protect from light |
| Typical analytical method | Reversed-phase high-performance liquid chromatography | Purity and related-substance testing |
| Identity confirmation | Mass spectrometry | Observed mass near 5.1 kDa for the intact peptide |
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.
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.
Measured responses usually involve growth hormone and insulin-like growth factor 1, known as IGF-1. Growth hormone rises in bursts and is difficult to sample reliably, while IGF-1 shifts more slowly and can be assessed from a single blood draw. Studies therefore treat IGF-1 as the more practical pharmacodynamic marker. Both are indirect, showing that the receptor was engaged rather than that the peptide reached a particular concentration. Direct exposure measurement requires an assay aimed at the molecule itself.
Published work tends to frame tesamorelin as a tool for studying the GHRH axis and as a compound with measurable effects on body composition. Reports often describe visceral adipose tissue as an endpoint, assessed by imaging rather than by inference. Analytical sections commonly describe liquid chromatography with tandem mass spectrometry to confirm identity and purity, because immunoassays may cross-react with related fragments. Where results diverge between studies, differences in assay choice, sampling timing, and population are frequent explanations offered. Whether effects persist after treatment stops remains an open question.
Tesamorelin binds the growth hormone–releasing hormone receptor on pituitary somatotroph cells. The receptor signals through the Gs protein, raising intracellular cAMP and activating protein kinase A. That cascade triggers release of stored growth hormone in pulses rather than a steady stream. Because the drug acts at the receptor that normally controls this process, its effect depends on the body's own signaling architecture rather than on a synthetic pathway. The resulting hormone profile reflects the timing of each pulse, not only its size.
Measuring the effect of a growth hormone-releasing hormone analogue requires markers that reflect pituitary output rather than the peptide itself. The two most frequently used are growth hormone and insulin-like growth factor 1. Growth hormone fluctuates sharply across the day and responds to sleep, stress, and meals, so isolated readings can be difficult to interpret. Insulin-like growth factor 1 changes more slowly and is often treated as the more stable integrated marker of axis activity.
Because growth hormone is released in pulses, single measurements can misrepresent overall secretion. Investigators sometimes use repeated sampling or overnight profiles to capture the pattern rather than a single value. Provocative testing, in which a stimulus is given and the response is tracked over time, offers another way to characterize the axis. Each approach carries trade-offs between sensitivity, burden on the participant, and the influence of non-target variables.
== Internet == Freedom House's Freedom on the Net2018 gave Thailand a score of 65 (0=best, 100=worst) for internet freedom. Not one of the eight ASEAN nations listed in the report achieved a "free" rating. Best was the Philippines; worst was Vietnam. Freedom House: In 2015 awarded Thailand an overall score of 63 ("not free") (0=best, 100=worst) for Internet freedom in the calendar year 2014, ranking 50 of 65 countries. In 2013 Thailand was rated as "partly free". International Telecommunication Union (ITU): In their 2012 report, ranked Thailand 92 of 155 countries for telecommunications infrastructure. Ookla Speedtest: The company known for its popular Internet utility, Speedtest, ranked all nations for rolling mean download speed in Mbps (megabit per second) in May 2015. Rankings are based on throughput over the previous 30 days to servers not more than 480 km from the client computer. Thailand ranked 52nd of 200 nations (20 Mbit/s). Other ASEAN nations ranked were Singapore (1 of 200 nations) 122 Mbit/s; Vietnam (61 of 200) 20 Mbit/s; Cambodia (110 of 200) 9 Mbit/s; Brunei (116 of 200) 8 Mbit/s; Malaysia (130 of 200) 7 Mbit/s; Laos (133 of 200) 7 Mbit/s; Indonesia (139 of 200) 7 Mbit/s; Myanmar (140 of 200) 7 Mbit/s; and the Philippines (176 of 200) 4 Mbit/s. According to Romanian internet security software firm Bitdefender, Thailand ranked fifth of 25 Asian nations in quantity of internet malware detected. India, Indonesia, China, and Vietnam were the top four cyber-security risks in Asia.
ResolutionThe complete restoration of the inflamed tissue back to a normal status. Inflammatory measures such as vasodilation, chemical production, and leukocyte infiltration cease, and damaged parenchymal cells regenerate. Such is usually the outcome when limited or short-lived inflammation has occurred. FibrosisLarge amounts of tissue destruction, or damage in tissues unable to regenerate, cannot be regenerated completely by the body. Fibrous scarring occurs in these areas of damage, forming a scar composed primarily of collagen. The scar will not contain any specialized structures, such as parenchymal cells, hence functional impairment may occur. Abscess formationA cavity is formed containing pus, an opaque liquid containing dead white blood cells and bacteria with general debris from destroyed cells. Chronic inflammationIn acute inflammation, if the injurious agent persists then chronic inflammation will ensue. This process, marked by inflammation lasting many days, months or even years, may lead to the formation of a chronic wound. Chronic inflammation is characterised by the dominating presence of macrophages in the injured tissue. These cells are powerful defensive agents of the body, but the toxins they release—including reactive oxygen species—are injurious to the organism's own tissues as well as invading agents. As a consequence, chronic inflammation is almost always accompanied by tissue destruction.
Some of these heavier isotopes (such as 291Mc, 291Fl, and 291Nh) may also undergo electron capture (converting a proton into a neutron) in addition to alpha decay with relatively long half-lives, decaying to nuclei such as 291Cn that are predicted to lie near the center of the island of stability. However, this remains largely hypothetical as no superheavy nuclei near the beta-stability line have yet been synthesized and predictions of their properties vary considerably across different models. In 2024, a team of researchers at the JINR observed one decay chain of the known isotope 289Mc as a product in the p2n channel of the reaction between 242Pu and 50Ti, an experiment targeting neutron-deficient livermorium isotopes. This was the first successful report of a charged-particle exit channel in a hot fusion reaction between an actinide target and a projectile with Z ≥ 20. The process of slow neutron capture used to produce nuclides as heavy as 257Fm is blocked by short-lived isotopes of fermium that undergo spontaneous fission (for example, 258Fm has a half-life of 370 μs); this is known as the "fermium gap" and prevents the synthesis of heavier elements in such a reaction. It might be possible to bypass this gap, as well as another predicted region of instability around A = 275 and Z = 104–108, in a series of controlled nuclear explosions with a higher neutron flux (about a thousand times greater than fluxes in existing reactors) that mimics the astrophysical r-process.
11 (6): 5839–5848. Bibcode:2014IJERP..11.5839R. doi:10.3390/ijerph110605839. PMC 4078551. PMID 24886754. Saad, Mehdi; Psimaras, Dimitri; Tafani, Camille; Sallansonnet-Froment, Magali; Calvet, Jean-Henri; Vilier, Alice; Tigaud, Jean-Marie; Bompaire, Flavie; Lebouteux, Marie; de Greslan, Thierry; Ceccaldi, Bernard; Poirier, Jean-Michel; Ferrand, François-Régis; Le Moulec, Sylvestre; Huillard, Olivier; Goldwasser, François; Taillia, Hervé; Maisonobe, Thierry; Ricard, Damien (1 April 2016). "Quick, non-invasive and quantitative assessment of small fiber neuropathy in patients receiving chemotherapy". Journal of Neuro-Oncology. 127 (2): 373–380. doi:10.1007/s11060-015-2049-x. PMID 26749101. S2CID 19058905. Leclair-Visonneau, Laurène; Bosquet, Tristan; Magot, Armelle; Fayet, Guillemette; Gras-Le Guen, Christèle; Hamel, Antoine; Péréon, Yann (2016). "Electrochemical skin conductance for quantitative assessment of sweat function: Normative values in children". Clinical Neurophysiology Practice. 1: 43–45. doi:10.1016/j.cnp.2016.07.001. PMC 6123897. PMID 30214959. Shahani, B T; Halperin, J J; Boulu, P; Cohen, J (1 May 1984). "Sympathetic skin response--a method of assessing unmyelinated axon dysfunction in peripheral neuropathies". Journal of Neurology, Neurosurgery & Psychiatry. 47 (5): 536–542. doi:10.1136/jnnp.47.5.536. PMC 1027833. PMID 6330307. Caccia, MR; Dezuanni, E; Salvaggio, A; Osio, M; Bevilacqua, M; Norbiato, G; Mangoni, A (1991).
== Synthesis == PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of hydroquinone, which is generated in situ by deprotonation with sodium carbonate. The reaction is conducted around 300 °C in polar aprotic solvents - such as diphenyl sulfone.
Sources: en.wikipedia.org
=== Fatty acid biosynthesis === The precursor for fatty acids is acetyl-CoA and it occurs in the cytosol of the cell. The overall net reaction, using palmitate (16:0) as a model substrate is: 8 Acetyl-coA + 7 ATP + 14 NADPH + 6H+ → palmitate + 14 NADP+ + 6H2O + 7ADP + 7P¡
Penn Station is configured with 11 platforms, 21 tracks, and four interlockings. The station's platforms and tracks are numbered from south to north. Tracks 1–4 are stub-end tracks ending at the eastern end of the platform and are used exclusively by NJ Transit, as they do not connect to the East River Tunnels. The remaining tracks 5 through 21 are through tracks with connections at both ends. In normal operations, Amtrak and NJ Transit share tracks 5–12, all three railroads share tracks 13–16, and the LIRR has the exclusive use of tracks 17–21 on the north side of the station. The station is accessed via seven single-track tunnels: two North River Tunnels under the Hudson River, four East River Tunnels under the East River, and one shorter Empire Tunnel under the West Side of Manhattan. Each under-river tunnel is approximately 3 miles long, while the Empire Tunnel is approximately 0.3 miles long. The interlockings that control the station complex are designated 'A', 'C', 'JO', and 'KN'. On the west side of the station, 'A' and 'KN' interlockings route trains to and from the North River Tunnels, the Empire Tunnel, and the West Side Yard. On the east side, two interlockings ('C' and 'JO') route trains to and from the four East River tunnels; each interlocking connects two of the tunnel tracks to only 17 of the 21 platform tracks, as tracks 1–4 do not connect to the east.
=== Yin yang and gender === Yin and yang were critical to the understanding of women's bodies, but understood only in conjunction with male bodies. Yin and yang ruled the body, the body being a microcosm of the universe and the earth. In addition, gender in the body was understood as homologous, the two genders operating in synchronization. Gender was presumed to influence the movement of energy and a well-trained physician would be expected to read the pulse and be able to identify two dozen or more energy flows. Yin and yang concepts were applied to the feminine and masculine aspects of all bodies, implying that the differences between men and women begin at the level of this energy flow. According to Bequeathed Writings of Master Chu the male's yang pulse movement follows an ascending path in "compliance [with cosmic direction] so that the cycle of circulation in the body and the Vital Gate are felt...The female's yin pulse movement follows a defending path against the direction of cosmic influences, so that the nadir and the Gate of Life are felt at the inch position of the left hand". In sum, classical medicine marked yin and yang as high and low on bodies which in turn would be labeled normal or abnormal and gendered either male or female. Bodily functions could be categorized through systems, not organs. In many drawings and diagrams, the twelve channels and their visceral systems were organized by yin and yang, an organization that was identical in female and male bodies. Female and male bodies were no different on the plane of yin and yang.
The professional tagmata regiments, first introduced in the mid-700s and consisting of native Byzantine units alongside foreign forces such as the Varangian Guard, had completely replaced them by the 11th century. The mobile tagmata, suitable for offensive warfare, evolved new tactical and strategic structures; the late 10th-century army, perhaps the highest-quality force the empire produced, numbered approximately 140,000, up from below 100,000 in the late 700s. However, its defensive capacities were neglected, especially during the 11th-century civil wars, leading to the loss of Anatolia to the Seljuks. The navy had also been reduced, as the empire increasingly relied on potentially hostile powers such as Venice. Post-1081 reforms re-established an effective army; the institution of feudal-like pronoia grants provided revenue to individuals in exchange for soldiers. The new army heavily relied on foreign mercenaries alongside indigenous Byzantine troops, but the financial demands of a standing army proved too much for the Byzantine state, which succumbed to the Fourth Crusade in 1204. The army of the Palaiologan dynasty, which retook Constantinople in 1261, was generally composed of a similar mix of mercenaries and indigenous troops, but it had lost all offensive capability by the late 1200s. The empire's continued survival depended on foreign armies; attempts in the 1340s to rebuild the fleet, unwisely disbanded in 1284, were forcibly halted by Genoa.
A thermostat operates by switching heaters or air-conditioners on and off in response to the output of a temperature sensor. Cruise control adjusts a car's throttle in response to changes in speed. An autopilot operates the steering controls of an aircraft or ship in response to deviation from a pre-set compass bearing or route. Process control systems in a chemical plant or oil refinery maintain fluid levels, pressures, temperature, chemical composition, etc. by controlling heaters, pumps and valves. The centrifugal governor of a steam engine, as designed by James Watt in 1788, reduces the throttle valve in response to increases in the engine speed, or opens the valve if the speed falls below the pre-set rate.
Sources: en.wikipedia.org
It mimics a natural hypothalamic signal that tells the pituitary to release growth hormone. The result is a rise in circulating growth hormone and, indirectly, in insulin-like growth factor 1. Over weeks of treatment this shift is associated with a selective decrease in fat stored inside the abdomen.
The primary measure is usually a cross-sectional abdominal scan that separates internal fat from fat just under the skin. Waist circumference and body weight are recorded as secondary measures because they are easy to obtain but do not distinguish the two fat compartments. Hormone and metabolic blood tests are collected alongside the imaging.
Available follow-up data indicate that visceral fat drifts back toward pretreatment levels once injections stop. The change is therefore best described as treatment-dependent rather than permanent. Investigators continue to debate whether intermittent or repeated courses would preserve any benefit.
Refrigeration between 2 and 8 degrees Celsius is typical, with protection from moisture and light. Dry, sealed containers help maintain stability over the labeled shelf life. Temperature cycling is usually minimized.