This is a working overview of IGF-1, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
Insulin-like growth factor 1 is produced largely in the liver in response to growth hormone signaling. Its concentration shifts over days rather than minutes, which makes it practical for tracking changes across a study period. Interpretation still depends on age, nutritional status, and concurrent illness, all of which independently affect the marker. Reference ranges are therefore stratified, and comparisons are usually made within an individual over time rather than against a single population threshold.
Assays for these markers differ in calibration and antibody specificity, so results from different platforms are not always interchangeable. Reported values can shift when a laboratory changes method, even without any biological change. Studies that span long periods or multiple sites often need cross-validation of assays. This methodological variability is a recognized limitation when comparing findings across published reports, and it remains a topic of ongoing standardization work.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | GHRH receptor agonist |
| Residue count | 44 amino acids | Matches human GHRH(1-44) length |
| N-terminal modification | trans-3-hexenoyl group | Confers resistance to dipeptidyl peptidase IV |
| Appearance | White to off-white powder | Typically supplied lyophilized in a sealed vial |
| Solubility class | Freely soluble in water | Hydrophilic peptide; polar solvent compatible |
特沙莫瑞林是一种合成肽，其序列与人生长激素释放激素的 44 个氨基酸形式相关。它在 N 端带有反式-3-己烯酰基修饰，这一改动可减缓二肽基肽酶 IV 的降解。该化合物属于生长激素释放激素受体激动剂，可刺激垂体释放生长激素。研究文献通常将其归入合成肽类药物，而非小分子化合物。
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。
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.
Tesamorelin is a synthetic peptide that acts as an analog of growth hormone-releasing hormone, a natural hypothalamic signal. Its sequence corresponds to the forty-four amino acid form of the human hormone, with a small acyl group attached near the amino terminus. That modification slows enzymatic breakdown and extends the time the peptide remains active in circulation. The compound was developed as a pharmacological way to raise endogenous growth hormone output rather than supplying the hormone directly.
After injection, the peptide binds receptors on somatotroph cells in the anterior pituitary. Receptor activation raises intracellular cyclic AMP and triggers release of stored growth hormone into the bloodstream. Because the compound works through the body's own regulatory system, growth hormone pulses retain much of their normal feedback control. Repeated administration also raises insulin-like growth factor 1, a hormone produced mainly in the liver. Investigators treat that rise as a marker that the pituitary axis has been engaged.
Clinical study of tesamorelin has centered on adults with HIV-associated lipodystrophy, a condition in which abdominal fat accumulates while peripheral fat is lost. In controlled trials, treated participants showed reductions in visceral adipose tissue measured by imaging, alongside modest shifts in some lipid values. Effects on subcutaneous fat were smaller and less consistent across studies. Whether these changes translate into fewer cardiovascular events remains an open question, because the trials were not designed or powered to answer it.
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.
In December 2013, a Formal Dispute Resolution was filed, which contained the requirements of the FDA for further studies. These include two studies in healthy subjects to determine if flibanserin impairs their ability to drive, and to determine if it interferes with other biochemical pathways. The Agency agreed to call a new Advisory Committee meeting to consider whether the risk-benefit ratio of flibanserin was favorable after this additional data was obtained. In June 2015, the US FDA Advisory Committee, which includes the Bone, Reproductive, and Urologic Drugs Advisory Committee (BRUDAC) and the Drug Safety and Risk Management Advisory Committee (DSRM), recommended approval of the drug by 18–6, with the proviso that measures be taken to inform women of the drug's side effects. On 18 August 2015, the FDA approved Addyi (flibanserin) for the treatment of premenopausal women with low sexual desire that causes personal distress or relationship difficulties. The approval specified that flibanserin should not be used to treat low sexual desire caused by co-existing psychiatric or medical problems; low sexual desire caused by problems in the relationship; or low sexual desire due to medication side effects. As of August 2015, Sprout Pharmaceuticals had not yet made an application to the European Medicines Agency for a marketing authorization.
=== 1969 === January 20: Richard Nixon becomes President of the United States. March 2: Border clashes between the Soviet Union and China. March 17: the U.S. begins bombing Communist sanctuaries in Cambodia. July 16: Apollo 11 is launched. July 20: the U.S. accomplishes the first crewed Moon landing, Apollo 11. Crewed by Neil Armstrong, "Buzz" Aldrin, and Michael Collins. July 24: Apollo 11 returns to Earth. July 25: "Vietnamization" begins with U.S. troop withdrawals from Vietnam and the burden of combat being placed on the South Vietnamese. September 1: Muammar Gaddafi overthrows the Libyan monarchy and expels British and American personnel. Libya aligns itself with the Soviet Union. September 2: North Vietnamese leader Ho Chi Minh dies. October 21: Siad Barre overthrows the government of Somalia in a bloodless coup. He declares himself President of Somalia and reorganizes the country into a one-party communist state; the Somali Democratic Republic. November 17: The Strategic Arms Limitation Talks begin in Helsinki. November 27–December 6: the al-Wadiah War was fought between South Yemen and Saudi Arabia. December 12: A bomb planted by far-right extremists sets off in a bank in Milan, Italy, killing 17 people and injuring 88. This event (remembered as the Piazza Fontana bombing) is one of the bloodiest terrorist attacks Italy would receive during the years of lead.
In 1995, the largest sperm bank in New York State was ordered to close (and no longer operate semen banks and blood banks), over the objections of its owner the Daxor Corporation and its president, CEO, and majority shareholder Joseph Feldschuh, by New York State Supreme Court Justice Harold Tompkins. The Justice found that Daxor had repeatedly endangered the public health over several years. A 1993 inspection had documented 517 violations by the sperm bank, including its failure to screen sperm donors properly for sexually transmitted diseases. Rather, the inspection showed that Daxor had, in fact, made available semen from men who had tested positive for hepatitis, chlamydia, and gonorrhea. Daxor employees told government investigators that Feldschuh had instructed them to make false entries on business records and to lie to investigators. Feldschuh claimed New York State Health Department officials were conspiring to shut down his business, sued them three times, appealed three times, and lost each of the six times. The Daxor sperm bank was sued for negligence by customers. In one case, a White mother sued the sperm bank because though her White terminally ill husband's sperm had been stored at the sperm bank, when she asked for the sperm and used it to artificially inseminate her, she ended up giving birth to a Black baby. In 2007 another mother settled her own claims against Daxor for $250,000, which she said was a fraction of the estimated $7 million in care that will be needed for both of her children.
Sources: en.wikipedia.org
In an organic light-emitting diode (OLED), the electroluminescent material composing the emissive layer of the diode is an organic compound. The organic material is electrically conductive due to the delocalization of pi electrons caused by conjugation over all or part of the molecule, and the material therefore functions as an organic semiconductor. The organic materials can be small organic molecules in a crystalline phase, or polymers. The potential advantages of OLEDs include thin, low-cost displays with a low driving voltage, wide viewing angle, and high contrast and color gamut. Polymer LEDs have the added benefit of printable and flexible displays. OLEDs have been used to make visual displays for portable electronic devices such as cellphones, digital cameras, lighting and televisions.
== Research == His main research was to uncover the basic mechanisms for how plants and bacteria use photosynthesis to convert light into chemical energy. In 1971, Feher's laboratory and Roderick Clayton's laboratory independently purified minimal bacterial photosynthetic reaction center preparations from Rhodobacter sphaeroides. Feher's main contributions to science were the development of spectroscopic tools and their applications, in particular, to problems in biochemistry and biophysics. He was the first to develop a form of double-frequency spectroscopy, Electron nuclear double resonance (ENDOR), for which he chose a name reminiscent of the biblical witch of Endor. This was the forerunner of many other double-resonance methods.
==== Detecting trojans ==== Machine learning models can potentially contain "trojans" or "backdoors": vulnerabilities that bad actors maliciously build into an AI system. For example, a trojaned facial recognition system could grant access when a specific piece of jewelry is in view; or a trojaned autonomous vehicle may function normally until a specific trigger is visible. This might not be difficult to do with some large models like CLIP or GPT-3 as they are trained on publicly available internet data. Researchers were able to plant a trojan in an image classifier by changing just 300 out of 3 million of the training images. In addition to posing a security risk, researchers have argued that trojans provide a concrete setting for testing and developing better monitoring tools. A 2024 research paper by Anthropic showed that large language models could be trained with persistent backdoors. These "sleeper agent" models could be programmed to generate malicious outputs (such as vulnerable code) after a specific date, while behaving normally beforehand. Standard AI safety measures, such as supervised fine-tuning, reinforcement learning and adversarial training, failed to remove these backdoors.
Sources: en.wikipedia.org
Geranylgeraniol 18-hydroxylase is a cytochrome P450 protein containing heme, isolated from Croton sublyratus. It requires a partner cytochrome P450 reductase for functional expression. This uses nicotinamide adenine dinucleotide phosphate.
== Reddit activity == In 2019 Cantelmo began posting on Reddit under the account u/ChrisCGC. He spent large amounts of money on Reddit awards (silver, gold, and platinum), often targeting posts and comments in youth-oriented subreddits such as r/teenagers. Through his main account he spent more than $70,000 on awards. Family members estimated the total outlay, including gifts to individuals, at roughly twice that figure or higher. Gifts reportedly included plane tickets, laptops, podcasting equipment, and in at least one case college tuition assistance. The award-giving attracted attention and led users to the subreddit r/Cantelmoism, created on April 16, 2019. Other related subreddits included r/ChrisCGC and r/ChildrenOfChris. Participants sometimes called themselves Cantelmoists and referred to Cantelmo in messianic terms, often with irony. Cantelmo stated that the awards were intended to draw attention to DMT and to keep conversations going. Cantelmo posted a series of claims about DMT.
Clematis alternata syn. Archiclematis alternata Clematis antonii, syn. Naravelia antonii Clematis dasyoneura, syn. Naravelia dasyoneura Clematis horripilata, syn. Naravelia laurifolia Clematis zeylanica, syn. Naravelia zeylanica
Neutrons produced by fission of 238U have lower energies than the original neutron (they behave as in an inelastic scattering), usually below 1 MeV (i.e., a speed of about 14,000 km/s), the fission threshold to cause subsequent fission of 238U, so fission of 238U does not sustain a nuclear chain reaction. Fast fission of 238U in the secondary stage of a thermonuclear weapon, due to the production of high-energy neutrons from nuclear fusion, contributes greatly to the yield and to fallout of such weapons. Fast fission of 238U tampers has also been evident in pure fission weapons. The fast fission of 238U also makes a significant contribution to the power output of some fast-neutron reactors.
Sources: en.wikipedia.org
The principal difference is a chemical cap on the N-terminal tyrosine that prevents rapid enzymatic cleavage. Native GHRH is degraded within minutes in plasma, whereas the modified peptide persists considerably longer. The amino acid backbone otherwise mirrors the natural hormone.
No. It is a receptor agonist that stimulates the pituitary to release endogenous growth hormone. It does not contain or deliver growth hormone. Its downstream effects therefore depend on a functioning pituitary and an intact signaling pathway.
Pituitary responsiveness, receptor availability, and the natural pulsatility of the growth hormone axis all contribute. Because the compound amplifies an existing release pattern rather than overriding it, timing and physiological state matter. Individual variability in response is well documented but not fully explained.
It varies slowly and reflects cumulative axis activity rather than momentary secretion. Growth hormone is released in pulses affected by sleep, stress, and meals, making single readings hard to interpret. The slower marker gives a more stable picture across a study period.