If you have been reading about GLP-1 receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-07-16. Numbers and descriptions here follow the published literature rather than marketing material.
Receptor binding triggers G protein signaling that raises intracellular cyclic AMP in pancreatic beta cells. Insulin release follows in a glucose-dependent manner, so secretion increases when blood glucose is elevated and diminishes when it is not. The same signaling suppresses glucagon release from alpha cells and slows gastric emptying, which blunts the post-meal glucose rise. In the brain, receptor activation in regions such as the arcuate nucleus is associated with reduced appetite and lower energy intake. How much each of these effects contributes to overall weight change is not fully settled.
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
Clinical studies of semaglutide generally measure glycated hemoglobin, fasting plasma glucose, body weight, and composite cardiovascular endpoints. The SUSTAIN program enrolled adults with type 2 diabetes, while the STEP program focused on obesity without diabetes. Administration follows a stepwise escalation schedule designed to limit gastrointestinal effects during the first weeks. Reported outcomes include mean percentage weight change, the proportion of participants reaching defined weight-loss thresholds, and rates of nausea, vomiting, and diarrhea. Long-term data on durability after treatment stops are still limited and remain a topic of ongoing research.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, developed by Novo Nordisk and first approved in 2017 for type 2 diabetes. It belongs to the incretin mimetic class, a group of agents that reproduce the glucose-dependent actions of endogenous GLP-1. The molecule was engineered to resist degradation by dipeptidyl peptidase-4 and to bind serum albumin, extending its half-life from minutes to roughly one week. Approval for chronic weight management followed in 2021, based on large cardiovascular and obesity outcome trials.
GLP-1 receptors are expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises cyclic AMP, enhances glucose-dependent insulin secretion, and suppresses glucagon release when blood glucose is high. Effects on gastric emptying and on hypothalamic appetite circuits reduce energy intake. Because insulin release remains glucose-dependent, the risk of hypoglycemia is low when the drug is used alone. The precise contribution of each pathway to body weight change in humans remains an area of active investigation.
| Property | Value | Notes |
|---|---|---|
| Chemical class | GLP-1 receptor agonist peptide | Mimics endogenous incretin signaling |
| Molecular mass | Approximately 4114 Da | Modified 31-amino-acid backbone |
| Appearance | White to off-white powder | Typical of lyophilized peptide material |
| Solubility | Soluble in water | Behavior depends on salt form and buffer |
| Elimination half-life | About one week | Supported by albumin binding and protease resistance |
Reported molecular weight is approximately 4113.6 daltons for the free base, and the peptide is supplied as a lyophilized powder or in buffered liquid form depending on the intended use. It is freely soluble in water when formulated with appropriate excipients, though the unconjugated peptide shows limited stability at neutral pH over long periods. Analytical characterization typically relies on reversed-phase high-performance liquid chromatography and mass spectrometry. Purity specifications for research-grade material commonly exceed ninety-five percent by area. Isotopic and impurity profiles differ between suppliers.
Two principal therapeutic variants exist under separate regulatory filings, one indicated for glycemic control in type 2 diabetes and one for chronic weight management. Both use the same active molecule; differences lie in formulation strength, titration schedule, and labeling. Regulatory agencies in the United States and European Union approved injectable forms in 2017 and 2018 respectively. An oral tablet formulation received approval later, using a carrier molecule to enhance absorption across the gastric epithelium. Labeling differs by jurisdiction and by indication.
Certificate of analysis documents from suppliers typically report purity by chromatographic area, water content, and counter-ion identity. Independent verification is advisable because reported values can be generated under differing conditions. Impurity profiles matter for research use, where aggregates, deamidation products, and residual solvents may influence experimental results. Container, lot, and chain-of-custody records support traceability. Analytical results are method-dependent, so comparisons between laboratories require the same procedure and reference standards.
Lyophilized peptide material is typically stored at or below -20 °C, with -80 °C used for longer-term archives. Vials should remain sealed and desiccated because moisture promotes aggregation and hydrolysis. Repeated freeze-thaw cycles are avoided since they can alter peptide conformation and reduce recovery. Once reconstituted, solutions are generally kept at 2-8 °C and used within a defined window. Stability beyond those windows depends on buffer composition and concentration, and exact limits are product-specific rather than universal.
Identity and purity are assessed with reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities by hydrophobicity. Mass spectrometry confirms molecular weight and detects truncation or modification products. Peptide mapping after enzymatic digestion verifies the amino acid sequence. Quantitation is often performed by LC-MS/MS or by immunoassay, and the two approaches can give different values because they measure different things. Method validation parameters such as accuracy, precision, and limit of quantitation are reported alongside results.
序列层面的改动同时解决了两个问题，即酶解稳定性与肾脏清除速度。天然 GLP-1 在循环中的半衰期仅约两分钟，主要被二肽基肽酶-4 迅速灭活。酰化侧链与白蛋白的可逆结合形成循环储库，使分子缓慢释放并持续激活受体。这种设计思路后来被广泛用于同类长效肽的开发，属于该类药物化学改造的典型范式。
Semaglutide 是一种经结构修饰的胰高血糖素样肽-1 类似物，其主链与内源性 GLP-1(7-36) 约有百分之九十四的序列一致性。第 8 位丙氨酸被 α-氨基异丁酸取代，使二肽基肽酶-4 无法识别原有切割位点。第 34 位赖氨酸换为精氨酸，进一步降低酶解速率。第 26 位赖氨酸经间隔基连接一条含十八个碳的二酸脂肪链，该侧链赋予分子与血浆白蛋白结合的能力。
该分子作为 GLP-1 受体的选择性激动剂发挥作用，受体属于 B 类 G 蛋白偶联受体家族，激活后经 Gs 通路提升细胞内环腺苷酸水平。在胰腺 β 细胞，信号促进葡萄糖依赖性的胰岛素释放，血糖偏低时该作用明显减弱。在胰岛 α 细胞，胰高血糖素分泌受到抑制。中枢神经系统与胃肠道同样存在受体表达，相应信号参与食欲调节以及胃排空速率的降低。
== Education and career == Bhatt graduated Boston Latin School, earned his science degree as a National Merit Scholar from MIT, an MD from Cornell and an MPH from Harvard. He received his Executive MBA from the University of Oxford in 2024. He trained in internal medicine and cardiology at the University of Pennsylvania and Cleveland Clinic, completing fellowships in interventional cardiology and cerebral and peripheral vascular intervention. He served as chief interventional fellow at Cleveland Clinic where he worked as an interventional cardiologist, associate professor of medicine, director of the interventional cardiology fellowship, associate director of the cardiovascular medicine fellowship, and associate director of the cardiovascular coordinating center. Later, he became the Chief of Cardiology at the VA Boston Healthcare System and, subsequently, the Interventional Cardiovascular Programs executive director at Brigham and Women's Hospital. Additionally, he was a Senior Investigator in the TIMI Study Group and Editor-in-Chief of the Harvard Heart Letter. In 2012, he was appointed a professor of medicine at Harvard Medical School.
== Optimizing protein purification == Combinations of chromatographic methods can be used to purify a target molecule. The purpose of purifying proteins with FPLC is to deliver quantities of the target at sufficient purity in a biologically active state to suit its further use. The quality of the end product varies depending the type and amount of starting material, efficiency of separation, and selectivity of the purification resin. The ultimate goal of a given purification protocol is to deliver the required yield and purity of the target molecule in the quickest, cheapest, and safest way for acceptable results. The range of purity required can be from that required for basic analysis (SDS-PAGE or ELISA, for example), with only bulk impurities removed, to pure enough for structural analysis (NMR or X-ray crystallography), approaching >99% target molecule. Purity required can also mean pure enough that the biological activity of the target is retained. These demands can be used to determine the amount of starting material required to reach the experimental goal. If the starting material is limited and full optimization of purification protocol cannot be performed, then a safe standard protocol that requires a minimum adjustment and optimization steps are expected. This may not be optimal with respect to experimental time, yield, and economy but it will achieve the experimental goal.
After the start of treatment, cats must be kept indoors for four weeks, and contact with pregnant women and children under the age of 16 must be avoided due to residual radioactivity. Just like a medical practice, any veterinary practice operating an X-ray machine must have sufficient staff with the appropriate expertise, as required by Section 18 of the X-Ray Ordinance 2002. The corresponding training for paraveterinary workers (then called veterinary nurses) took place in 1990. In 2017, Linsengericht (Hesse) opened Europe's first clinic for horses with cancer. Radiation therapy is administered in a treatment room that is eight meters wide, on a specially designed table that can withstand heavyweight. The surrounding area is protected from radiation by three-meter thick walls. Mobile equipment is used to irradiate tumors in small animals at various locations.
Kenner's work was recognised by the awards of the Meldola Medal (1951) and the Corday-Morgan Medal (1957) and in distinguished lectureships such as Tilden (1955), Simonsen (1972) and Pedler (1976) of the Chemical Society of whose Perkin Division he was President from 1974 to 1976. He was also President of Section B of the British Association for the Advancement of Science in 1974. Elected a Fellow of the Royal Society in 1964 he was the Society's Bakerian Lecturer for 1976 and was elected to a Royal Society Research Professorship in 1976.
=== Implicated in deaths === In June 2009, an FDA advisory panel recommended that Percocet, Vicodin, and every other combination of acetaminophen with narcotic analgesics be limited in their sales because of their contributions to an alleged 400 acetaminophen-related deaths in the U.S. each year, that were attributed to acetaminophen overdose and associated liver damage. In December 2009, a study found a fivefold increase in oxycodone-related deaths in Ontario, Canada (mostly accidental) between 1991 and 2007; this led to a doubling of all opioid-related deaths in Ontario over the same period.
Sources: en.wikipedia.org
Gallium (68Ga) gozetotide or Gallium (68Ga) PSMA-11, is a radiopharmaceutical made of 68Ga conjugated to a inhibitor of the enzyme prostate-specific membrane antigen (PSMA) known as Glu-Urea-Lys(Ahx)-HBED-CC. It is used for imaging prostate cancer by positron emission tomography (PET). The PSMA inhibitor specifically directs the radiolabeled imaging agent towards the prostate cancerous lesions in men. The most common side effects with gallium (68Ga)-radiolabelled gozetotide are tiredness, nausea (feeling sick), constipation and vomiting. Gallium (68Ga) gozetotide was approved for medical use in the United States in December 2021, and in the European Union in December 2022. It is the first drug approved by the US Food and Drug Administration (FDA) as a PET imaging agent of prostate-specific membrane antigen (PSMA) positive lesions in men with prostate cancer.
== AMPA Receptors in Disease Beyond Epilepsy == AMPA receptors are essential to excitatory neurotransmission in the CNS. Beyond their established role in epilepsy, recent research indicates that AMPARs are implicated in various neurological and psychiatric disorders, including excitotoxicity in stroke and neurodegeneration, as well as conditions such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Huntington's disease, schizophrenia, and autism spectrum disorders (ASD).
Schleiden was a microscopist and an early plant anatomist who co-founded the cell theory with Theodor Schwann and Rudolf Virchow and was among the first to grasp the significance of the cell nucleus that had been described by Robert Brown in 1831. In 1855, Adolf Fick formulated Fick's laws that enabled the calculation of the rates of molecular diffusion in biological systems.
== Function == Human chorionic gonadotropin interacts with the LHCG receptor of the ovary and promotes the maintenance of the corpus luteum for the maternal recognition of pregnancy at the beginning of pregnancy. This allows the corpus luteum to secrete the hormone progesterone during the first trimester. Progesterone enriches the uterus with a thick lining of blood vessels and capillaries so that it can sustain the growing fetus. It has been hypothesized that hCG may be a placental link for the development of local maternal immunotolerance. For example, hCG-treated endometrial cells induce an increase in T cell apoptosis (dissolution of T cells). These results suggest that hCG may be a link in the development of peritrophoblastic immune tolerance, and may facilitate the trophoblast invasion, which is known to expedite fetal development in the endometrium. It has also been suggested that hCG levels are linked to the severity of morning sickness or hyperemesis gravidarum in pregnant women. Because of its similarity to LH, hCG can also be used clinically to induce ovulation in the ovaries as well as testosterone production in the testes. As the most abundant biological source is in women who are presently pregnant, some organizations collect urine from pregnant women to extract hCG for use in fertility treatment. Human chorionic gonadotropin also plays a role in cellular differentiation/proliferation and may activate apoptosis.
== Drug screening == Types of drug screening include phenotypic screening, high-throughput screening, and virtual screening. Phenotypic screening is characterized by the process of screening drugs using cellular or animal disease models to identify compounds that alter the phenotype and produce beneficial disease-related effects. Emerging technologies in high-throughput screening substantially enhance processing speed and decrease the required detection volume. Virtual screening is completed by computer, enabling a large number of molecules can be screened with a short cycle and low cost. Virtual screening uses a range of computational methods that empower chemists to reduce extensive virtual libraries into more manageable sizes.
Sources: en.wikipedia.org
Nicholson at Birkbeck College, University of London and later at Imperial College London. In 1984, Nicholson showed 1H NMR spectroscopy could potentially be used to diagnose diabetes mellitus, and later pioneered the application of pattern recognition methods to NMR spectroscopic data. In 1994 and 1996, liquid chromatography mass spectrometry metabolomics experiments were performed by Gary Siuzdak while working with Richard Lerner (then president of the Scripps Research Institute) and Benjamin Cravatt, to analyze the cerebral spinal fluid from sleep deprived animals. One molecule of particular interest, oleamide, was observed and later shown to have sleep inducing properties. This work is one of the earliest such experiments combining liquid chromatography and mass spectrometry in metabolomics. In 2005, the first metabolomics tandem mass spectrometry database, METLIN, for characterizing human metabolites was developed in the Siuzdak laboratory at the Scripps Research Institute. METLIN has since grown and as of 2025, METLIN contains MS/MS experimental data on over 960,000 molecular standards and other chemical entities, each compound having experimental tandem mass spectrometry data generated from molecular standards at multiple collision energies and in positive and negative ionization modes. METLIN is the largest repository of tandem mass spectrometry data of its kind. The dedicated academic journal Metabolomics first appeared in 2005, founded by its current editor-in-chief Roy Goodacre.
== Medical Uses == Sorafenib is used as an oral drug which inhibits angiogenesis and tumor cell growth in VEGFR-2 and VEGFR-3 (inhibits the phosphorylation), PDGFRβ (platelet-derived growth factor receptor), RAF kinase, FLT3 (Fms-like tyrosine kinase-3) and KIT (stem cell factor receptor). Sorafenib is used in the treatment of advanced renal cell carcinoma. As of October 2018, it is in phase III of clinical trials for hepatocellular carcinoma, metastatic melanoma and non-small cell lung cancer (NSCLC). Sunitinib is an oral drug that inhibits the phosphorylation of all the VEGF receptors, PDGFR-ß, KIT FLT3, CSF1R and GDNF. Sunitinib is used in the treatment of advanced renal cell carcinoma and gastrointestinal stromal tumors. Bevacizumab is a humanized monoclonal antibody, which binds selectively to VEGF. It is used as an injection therapy, often in combination with other drugs. It is used in combination with 5-fluorouracil as a first-line treatment of metastatic carcinoma in the colon or rectum. In advanced non-small cell lung cancer bevacizumab (Avastin) is used as a first-line treatment in combination with paclitaxel and carboplatin. It can also be used in the treatment for breast cancer and kidney cancer. Lenvatinib and vandetanib are used for the treatment of progressive and locally advanced differentiated thyroid cancer (DTC). Pazopanib and axitinib are used orally for the treatment of advanced renal cell carcinoma. Cabozantinib has the same indication but it is only used on patients who have already received an anti-angiogenic therapy.
fuels, materials, active pharmaceutical ingredients) and the discovery of new riboflavin cofactors. He has supervised about 70 students for the degree of Doctor of Philosophy, as well as about 60 postdoctoral research workers. He has published over 500 research papers and several patents. In 2015, Scrutton co-founded the company C3 Biotechnologies Ltd to commercialise technologies for chemicals, fuels and materials production. He was founding Director of the Manchester Synthetic Biology Research Centre SYNBIOCHEM, which he established in 2014 following major investment by the UK government in synthetic biology. In 2019, he established and became Director of the UK Future Biomanufacturing Research Hub, which is developing new technologies to accelerate bio-based manufacturing in the UK in three key sectors – pharmaceuticals, chemicals and engineering materials. He has served on several national committees, including research council / funding committees (BBSRC, EPSRC, Royal Society) and strategic advisory boards / scientific steering groups (e.g. Science and Technology Facilities Council). He is a former member of BBSRC Council (2021-24). While serving as Director, the MIB was awarded the Queen's Anniversary Prize for Higher and Further Education (2018–20).
== Prognosis == Prognosis of spontaneous cervical arterial dissection involves neurological and arterial results. The overall functional prognosis of individuals with stroke due to cervical artery dissection does not appear to vary from that of young people with stroke due to other causes. The rate of survival with good outcome (a modified Rankin score of 0–2) is generally about 75%, or possibly slightly better (85.7%) if antiplatelet drugs are used. In studies of anticoagulants and aspirin, the combined mortality with either treatment is 1.8–2.1%. After the initial episode, 2% may experience a further episode within the first month. After this, there is a 1% annual risk of recurrence. Those with high blood pressure and dissections in multiple arteries may have a higher risk of recurrence. Further episodes of cervical artery dissection are more common in those who are younger, have a family history of cervical artery dissection, or have a diagnosis of Ehlers-Danlos syndrome or fibromuscular dysplasia.
=== Color rendering === The spectrum of light produced by an incandescent lamp closely approximates that of a black body radiator at the same temperature. The basis for light sources used as the standard for color perception is a tungsten incandescent lamp operating at a defined temperature.
Sources: en.wikipedia.org
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and cleared quickly. Semaglutide carries a position 8 substitution that blocks that cleavage and a fatty diacid chain that binds albumin. Together these changes extend its circulating half-life to about one week.
Yes. Stimulation of insulin secretion is glucose-dependent, meaning the effect is larger when blood glucose is high and minimal when it is normal. This property separates GLP-1 receptor agonists from agents that drive insulin release regardless of glucose level.
Receptor expression in hypothalamic and brainstem regions is well documented, and reduced energy intake is consistently observed. The relative contribution of central versus peripheral signaling to total weight change is still an open question addressed by ongoing research.
It is given either as a once-weekly subcutaneous injection or as an oral tablet taken once daily. The two forms use different absorption strategies, so they are not interchangeable on a milligram-for-milligram basis.