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.
Last reviewed on 2025-11-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
The sequence incorporates alpha-aminoisobutyric acid at position 8, replacing the alanine found in the natural hormone. This substitution blocks the primary DPP-4 recognition site and contributes most of the enzymatic stability. Albumin binding further protects the peptide and reduces the frequency of administration required to maintain active plasma levels. Because the fatty acid chain increases lipophilicity, the compound is formulated as a solution rather than a simple aqueous buffer. Researchers describe the design as an incremental optimization of earlier GLP-1 analogs rather than a wholly new scaffold.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 or 280 nanometres is widely used to assess purity and to resolve related impurities. Liquid chromatography coupled to mass spectrometry confirms identity through the protonated molecular ion and fragment ions formed in tandem experiments. Capillary electrophoresis and peptide mapping after enzymatic digestion supply complementary information on charge variants and modification sites. Circular dichroism and nuclear magnetic resonance can report on secondary structure in solution. Absolute quantification usually depends on an external standard, and reported purity depends on the detection wavelength and integration parameters chosen.
Lyophilised material appears as a white to off-white cake or powder that is hygroscopic, and containers are usually equilibrated to room temperature before opening to limit condensation. Dissolution is performed in water, phosphate-buffered saline, or a mildly alkaline buffer, since solubility rises above neutral pH. Gentle inversion or low-speed mixing is preferred, because vigorous vortexing can promote surface denaturation and aggregation. Complete dissolution may require several minutes, and brief sonication is sometimes applied. Passing the solution through a 0.22 micrometre membrane removes particulates but does not by itself sterilise the liquid.
| Property | Value | Notes |
|---|---|---|
| Molecular formula (free base) | C187H291N45O59 | Approximate; salt and hydrate forms differ |
| Molecular weight | ~4113.6 Da | Varies with counterion and hydration |
| Appearance | White to off-white powder | Lyophilized research material |
| Solubility class | Freely soluble in water | As formulated; native peptide less stable near neutral pH |
| Typical storage | 2 to 8 degrees Celsius | Protect from light; avoid repeated freeze-thaw |
Stability studies examine how temperature, pH, and moisture influence degradation rates over time. In aqueous solution, hydrolysis and deamidation accelerate as pH moves away from mildly acidic conditions. Light exposure and residual metal ions can also trigger oxidation of susceptible residues. Accelerated aging at elevated temperature is used to estimate shelf life, though extrapolation to room temperature carries uncertainty because individual degradation pathways do not always scale predictably.
Lyophilized semaglutide powder is typically held at minus twenty degrees Celsius for long-term storage. At that temperature, solid-state degradation reactions proceed slowly and the peptide remains intact for extended periods. Repeated freeze-thaw cycles are best avoided because they promote aggregation and can shift the proportion of monomeric peptide present. Working aliquots are often prepared so that each portion is thawed only once, and desiccant is placed inside the vial to limit moisture uptake.
Identity and purity are usually assessed by reverse-phase high-performance liquid chromatography coupled to mass spectrometry. Retention time and observed mass are compared against a reference standard run under identical conditions. Impurity profiles reveal deamidation products, oxidized methionine variants, and truncated fragments that arise during synthesis or storage. Peptide mapping through enzymatic digestion confirms the primary sequence, while amino acid analysis offers an independent check on overall composition.
Semaglutide dissolves readily in water and in aqueous buffers near neutral pH. Solubility decreases near the isoelectric point, where net charge is minimal. Common laboratory solvents include phosphate-buffered saline and dilute ammonium bicarbonate. Strongly acidic or basic conditions may accelerate hydrolysis. Working concentrations are usually prepared by diluting a concentrated stock. Vial surfaces can adsorb small amounts of peptide at low concentrations, so carrier proteins or low-binding tubes are sometimes used.
Reverse-phase high-performance liquid chromatography is the standard method for purity assessment, separating the peptide from truncated or oxidized variants. Mass spectrometry confirms molecular mass and detects modifications, while ultraviolet absorbance near 280 nanometers supports concentration measurement through tryptophan and tyrosine residues. Circular dichroism can indicate secondary structure, though the peptide is largely helical in solution, and ion-exchange chromatography resolves charge variants. Purity values above 95 percent are typical for research-grade material. Stability studies track degradation over time under defined conditions.
Lyophilized semaglutide is typically stored at temperatures between minus 20 and minus 80 degrees Celsius for long-term preservation. Short-term storage at 2 to 8 degrees Celsius is common for working aliquots. Repeated freeze-thaw cycles can degrade the peptide and are usually avoided. The molecule is hygroscopic in its solid form, so containers should remain sealed with desiccant. Solutions are less stable than powders and are generally prepared fresh. Light exposure is limited because aromatic residues can undergo photo-oxidation.
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。
皮下注射后吸收相对缓慢，绝对生物利用度约为百分之八十九，血药浓度峰值通常出现在给药后一到三天。与白蛋白结合使清除减慢，终末半衰期约为一百六十五小时，接近一周。连续给药约四到五周后达到稳态暴露水平。表观分布容积约为每千克零点二五升，血浆蛋白结合率超过百分之九十九。代谢以蛋白水解切割和脂肪二酸侧链的 β-氧化为主，相关产物主要经尿液与粪便排出。
Activation of the GLP-1 receptor couples to Gs signalling and raises intracellular cyclic AMP in pancreatic beta cells. The resulting insulin release depends on prevailing glucose concentrations, so the effect is greater when glucose is elevated. Receptor engagement also suppresses glucagon secretion and slows gastric emptying, which flattens post-meal glucose excursions. In the central nervous system, signalling in hypothalamic and brainstem regions is associated with reduced appetite and lower energy intake. Studies continue to examine effects on cardiac, renal and hepatic endpoints; whether those benefits are independent of weight change remains an open question.
Clinical development of this compound followed earlier short-acting GLP-1 analogues that required frequent injection. Once-weekly subcutaneous formulations entered use after 2017, and an oral formulation using a permeation enhancer later became available. The oral version pairs the peptide with sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, a carrier that improves uptake across the gastric epithelium. Interest has expanded from glycaemic control into weight management and metabolic liver disease. Regulatory status and approved indications differ between countries, and the product remains subject to ongoing safety monitoring.
Semaglutide is a synthetic peptide that acts as an agonist at the glucagon-like peptide-1 receptor. It is a structural analogue of human GLP-1(7-37), modified to resist enzymatic degradation by dipeptidyl peptidase-4. The peptide backbone contains alpha-aminoisobutyric acid at position 8, a substitution that stabilises the helix and slows cleavage. A fatty diacid side chain attached through a linker at lysine 34 promotes binding to serum albumin, which extends the circulating half-life. These two modifications together allow less frequent administration than native GLP-1 requires.
=== Evolution === The date of the appearance of smallpox is not settled. It most probably evolved from a terrestrial African rodent virus between 68,000 and 16,000 years ago. The wide range of dates is due to the different records used to calibrate the molecular clock. One clade was the variola major strains (the more clinically severe form of smallpox) which spread from Asia between 400 and 1,600 years ago. A second clade included both alastrim (a phenotypically mild smallpox) described from the American continents and isolates from West Africa which diverged from an ancestral strain between 1,400 and 6,300 years before present. This clade further diverged into two subclades at least 800 years ago. A second estimate has placed the separation of variola virus from Taterapox (an Orthopoxvirus of some African rodents including gerbils) at 3,000 to 4,000 years ago. This is consistent with archaeological and historical evidence regarding the appearance of smallpox as a human disease which suggests a relatively recent origin. If the mutation rate is assumed to be similar to that of the herpesviruses, the divergence date of variola virus from Taterapox has been estimated to be 50,000 years ago. A strain that dates from c. 1650 has been shown to be basal to the other presently sequenced strains.
On January 26, 2006, Chipotle made its initial public offering (IPO) after increasing the share price twice due to high pre-IPO demand. At the time, Chipotle had 500 stores. In its first day as a public company, the stock rose exactly 100%, resulting in the best U.S.-based IPO in six years, and the second-best IPO for a restaurant after Boston Market. The money from the offering was then used to fund new store growth. In March 2005, Monty Moran was appointed president and chief operating officer of Chipotle while Ells remained chairman and CEO. In October 2006, McDonald's fully divested from Chipotle. This was part of a larger initiative for McDonald's to divest all of its non-core business restaurants—Chipotle, Donatos Pizza, and Boston Market—so that it could focus on the main McDonald's chain. McDonald's had invested approximately $360 million into Chipotle, and took out $1.5 billion. McDonald's had attempted to get Chipotle to add drive-through windows and a breakfast menu, which Ells resisted. In 2008, Chipotle opened its first location outside of the United States in Toronto. In January 2009, president and chief operating officer Monty Moran was promoted to co-CEO, a position that he would share with Ells, while Moran retained his president position. In a list of fastest-growing restaurant chains in 2009, Chipotle was ranked eighth, based on increases in U.S. sales over the past year, and in 2010 Chipotle was ranked third. Consumer Reports ranked Chipotle as the best Mexican fast-food chain in 2011. The company serves approximately 750,000 customers per day.
== Efficacy == The COVID-19 mRNA vaccines from Moderna and Pfizer–BioNTech had short-term efficacy rates of over 90 percent against the original SARS-CoV-2 virus. Prior to mRNA, drug trials on pathogens other than COVID-19 were not effective and had to be abandoned in the early phases of trials. The reason for the efficacy of the new mRNA vaccines is not clear. Physician-scientist Margaret Liu stated that the efficacy of the new COVID-19 mRNA vaccines could be due to the "sheer volume of resources" that went into development, or that the vaccines might be "triggering a nonspecific inflammatory response to the mRNA that could be heightening its specific immune response, given that the modified nucleoside technique reduced inflammation but hasn't eliminated it completely", and that "this may also explain the intense reactions such as aches and fevers reported in some recipients of the mRNA SARS-CoV-2 vaccines". These reactions though severe were transient and another view is that they were believed to be a reaction to the lipid drug delivery molecules. In June 2021, the US Food and Drug Administration added a warning about the possibility of increased risk of myocarditis and pericarditis for some people.
== Anatomy == Alpha cells are endocrine cells, meaning they secrete a hormone, in this case glucagon. Alpha cells store this glucagon in secretory vesicles that typically have an electron dense core and a grayish outer edge. It is believed that alpha cells make up approximately 20% of endocrine cells within the pancreas. Alpha cells are most commonly found on the dorsal side of the pancreas and are very rarely found on the ventral side of the pancreas. Alpha cells are typically found in compact Islets of Langerhans, which are themselves typically found in the body of the pancreas.
==== Military music ==== The very first stage of Western adaptation in the Meiji period is associated with the military field. A little before the reopening of Japan, the first military academy based on Dutch model was founded in Nagasaki where, alongside the military training, military music was taught, since it was acknowledged to be an important component of the martial arts. The first military band, called kotekitai, consisted of woodwind instruments and drums, was organized there. Gradually, Western music became an integral part of the Japanese culture where the importance of Western music was undertaken as a part of a social project. The military bands played prominent role in the society. That included public concerts of Western music, which were held in a famous Rokumeikan Hall and Hibiya Open-Air stage in Tokyo, performing marches, patriotic music and European composers’ works (Richard Wagner, Charles Gounod, Peter Tchaikovsky). With the contribution of foreign and Japanese authors, the first military music score collections were completed and published. In the military field, the Japanese conducting school was formed, the founders of which were English, French and German cultural figures such as John William Fenton, Charles Leroux, and Franz Eckert. Under their leadership, the first Japanese military conductors were raised: Suketsune Nakamura and Yoshitoyo Yotsumoto.
Sources: en.wikipedia.org
Cy1: Curly; the wings curve away from the body, flight may be somewhat impaired e1: Ebony; black body and wings (heterozygotes are also visibly darker than wild type) Sb1: Stubble; bristles are shorter and thicker than wild type w1: White; eyes lack pigmentation and appear white bw: Brown; eye color determined by various pigments combined. y1: Yellow; body pigmentation and wings appear yellow, the fly analog of albinism
In December 2000, Dutch journalist Marjon van Royen found that "because the chemical is sprayed in Colombia from planes on inhabited areas, there have been consistent health complaints [in humans]. Burning eyes, dizziness and respiratory problems being most frequently reported." In some areas, 80 percent of the children of the indigenous community fell sick with skin rashes, fever, diarrhoea and eye infections. Because the glyphosate is sprayed from the air, there is a much higher chance of human error when spraying suspected illegal coca plantations. In many cases the wrong fields are sprayed, resulting in not only a total loss of the farmer's crop- but the loss of that field altogether as nothing will grow where the herbicide has been sprayed. Though official documentation of the health effects of glyphosate spraying in Colombia are virtually non-existent, neighbouring Ecuador has conducted studies to determine the cause of mysterious illnesses amongst people living along the border of Colombia and has since demanded that no aerial sprayings occur within 10 km of the border because of the damages caused to the people, animals and environment in that area. In 2015, Colombia announced a ban on using glyphosate in these programs due to concerns about human toxicity of the chemical.
Mass spectrometry is a technique which allows for the measurement of molecular mass and offers complementary data to spectroscopic techniques for structural identification. In a typical experiment a gas phase sample of an organic material is ionized and the resulting ionic species are accelerated by an applied electric field into a magnetic field. The deflection imparted by the magnetic field, often combined with the time it takes for the molecule to reach a detector, is then used to calculate the mass of the molecule. Often in the course of sample ionization large molecules break apart, and the resulting data show a parent mass and a number of smaller fragment masses; such fragmentation can give rich insight into the sequence of proteins and nucleic acid polymers. In addition to the mass of a molecule and its fragments, the distribution of isotopic variant masses can also be determined and the qualitative presence of certain elements identified due to their characteristic natural isotope distribution. The ratio of fragment mass population to the parent ion population can be compared against a library of empirical fragmentation data and matched to a known molecular structure. Combined gas chromatography and mass spectrometry is used to qualitatively identify molecules and quantitatively measure concentration with great precision and accuracy, and is widely used to test for small quantities of biomolecules and illicit narcotics in blood samples. For synthetic organic chemists it is a useful tool for the characterization of new compounds and reaction products.
=== Legal status === In January 2016, Eli Lilly submitted a new drug application to the US Food and Drug Administration (FDA) for the approval of baricitinib to treat moderately-to-severely active rheumatoid arthritis. In December 2016, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recommended the approval of baricitinib as a therapy for rheumatoid arthritis. European Union approval was granted in February 2017. Despite widespread expectations that the FDA would approve baricitinib for rheumatoid arthritis, in April 2017, the FDA issued a rejection, citing concerns about dosing and safety. In May 2018, baricitinib was approved in the United States for the treatment of rheumatoid arthritis. In March 2020, the US FDA granted breakthrough therapy designation to baricitinib for the treatment of alopecia areata and granted approval in June 2022. The efficacy and safety of baricitinib in alopecia areata was studied in two randomized, double-blind, placebo-controlled trials (Trial AA-1 and Trial AA-2) with participants who had at least 50% scalp hair loss as measured by the Severity of Alopecia Tool (SALT) for more than six months. Participants in these trials received either a placebo, 2 milligrams of baricitinib, or 4 milligrams of baricitinib every day. The primary measurement of efficacy for both trials was the proportion of participants who achieved at least 80% scalp hair coverage at week 36.
14 August – Police are investigating the deaths of two 18-year-olds who attended an event at Glasgow's SWG3 venue. 16 August – Junior doctors in Scotland have voted to accept a pay offer from the Scottish Government worth 4.5% for 2022–23 and 12.4% for 2023–24. 17 August – GMB Scotland announces that non-teaching staff in ten Scottish council areas will stage two days of strike action on 13 and 14 September. The Scottish Parliament plays host to Comedy Unleashed, starring Father Ted creator Graham Linehan, after the show is cancelled by two venues in Edinburgh. Carnbooth House, a listed building and former hotel in Glasgow, is destroyed by fire. 22 August – Broadcaster Nicky Campbell gives evidence to the Scottish Child Abuse Inquiry, where he alleges that a teacher who worked at two Edinburgh schools abused children on a "Savile scale". 23 August – Murray Foote is appointed as the SNP's new chief executive, replacing Peter Murrell. 25 August – Alexander McKellar, who killed a cyclist on a remote road in the Scottish Highlands while drink driving in September 2017 and then hid the body, is sentenced to 12 years in prison. Members of Unison in 24 of Scotland's 32 council areas vote to take industrial action after rejecting a 5.5% pay offer. 26 August – A search for the Loch Ness Monster, described as the largest in 50 years, gets underway both in the vicinity of Loch Ness itself, and through an online stream of the loch. A group of people looking for the creature subsequently claim to have heard sounds, but fail to record anything.
Sources: en.wikipedia.org
Bipolar cell A type of amacrine cell that transmits signals from photoreceptors (rods and cones) to ganglion cells in the eye, playing a key role in visual processing. Bipolar disorder A mood disorder characterized by alternating episodes of depression and mania, associated with dysregulation in neurotransmitter systems and structural brain changes. Blood–brain barrier (BBB) A selective barrier formed by endothelial cells lining brain capillaries that restricts the passage of substances from the bloodstream into the central nervous system, protecting the brain from pathogens and toxins. Bouton Also known as an axon terminal or synaptic bouton, this is the swollen end of an axon where neurotransmitters are released into the synaptic cleft. Brain The central organ of the nervous system, responsible for processing sensory information, regulating bodily functions, and enabling thought, emotion, memory, and consciousness. Brain-derived neurotrophic factor (BDNF) A protein that supports the survival of existing neurons and encourages the growth and differentiation of new neurons and synapses. It is crucial for long-term memory and synaptic plasticity. Brain plasticity Also called neuroplasticity, this refers to the brain’s ability to reorganize and adapt by forming new neural connections throughout life, especially after injury or in response to learning and experience. Brainstem The posterior part of the brain that connects the cerebrum with the spinal cord.
=== Vascular disease === The infusion of a FFAR2-activating SCFA, i.e. acetic, propionic, or butyric acid, into mice causes short-term falls in their blood pressure. Similarly, patients undergoing hemodialysis that uses a hemodialysis solution containing acetic acid have an increased risk of becoming hypotensive compared to patients dialyzed with an acetic acid-free solution. Long-term oral intake of FFAR2-activating SCFAs also lower blood pressure in mice and humans. Furthermore, FFAR2 gene knockout mice developed perivascular fibrosis (which is an indicator of blood vessel disease), higher end-diastolic blood pressures, and higher pulse pressures. Mice lacking both FFAR2 and FFAR3 had exaggerated responses to hypertension; this seems to happen via changes to the gut epithelial barrier and activation of the immune system. Finally, in the angiotensin II–infusion model of hypertension, mice had reduced levels of FFAR2 in their kidney tissues compared to control mice and a study in humans reported that the levels of FFAR2 in the circulating white blood cells of hypertensive individuals was significantly lower than that in individuals with normal blood pressures. These findings suggest that FFAR2 functions to reduce blood pressure as well as hypertension induced vascular disease in mice and humans and support further studies to examine these relationships.
When women reach menopause and the estrogen produced by the ovaries declines, fat migrates from the buttocks, hips and thighs to the waist; later fat is stored in the abdomen. Visceral fat can be caused by excess cortisol levels. At least 10 MET-hours per week of aerobic exercise leads to visceral fat reduction in those without metabolic-related disorders. Resistance training and caloric restriction also reduce visceral fat, although their effect may not be cumulative. Both exercise and hypocaloric diet cause loss of visceral fat, but exercise has a larger effect on visceral fat versus total fat. High-intensity exercise is one way to effectively reduce total abdominal fat. An energy-restricted diet combined with exercise will reduce total body fat and the ratio of visceral adipose tissue to subcutaneous adipose tissue, suggesting a preferential mobilization for visceral fat over subcutaneous fat.
All cells in animal body tissues are electrically polarized – in other words, they maintain a voltage difference across the cell's plasma membrane, known as the membrane potential. This electrical polarization results from a complex interplay between protein structures embedded in the membrane called ion pumps and ion channels. In neurons, the types of ion channels in the membrane usually vary across different parts of the cell, giving the dendrites, axon, and cell body different electrical properties. As a result, some parts of the membrane of a neuron may be excitable (capable of generating action potentials), whereas others are not. Recent studies have shown that the most excitable part of a neuron is the part after the axon hillock (the point where the axon leaves the cell body), which is called the axonal initial segment, but the axon and cell body are also excitable in most cases. Each excitable patch of membrane has two important levels of membrane potential: the resting potential, which is the value the membrane potential maintains as long as nothing perturbs the cell, and a higher value called the threshold potential. At the axon hillock of a typical neuron, the resting potential is around −70 millivolts (mV) and the threshold potential is around −55 mV. Synaptic inputs to a neuron cause the membrane to depolarize or hyperpolarize; that is, they cause the membrane potential to rise or fall. Action potentials are triggered when enough depolarization accumulates to bring the membrane potential up to threshold.
Sources: en.wikipedia.org
It is a modified version of the natural hormone, with three amino acid changes and a fatty acid side chain added. These edits extend its half-life from minutes to about one week. The core receptor activity is retained.
Both deliver the same active peptide and act on the same receptor. The tablet includes an absorption enhancer because peptides are poorly taken up intact from the gut. Bioavailability of the oral route is substantially lower, so the two are not dose-equivalent.
No, it is entirely synthetic and does not occur in nature. Native GLP-1 is produced in the gut and pancreas, but the analog is manufactured by chemical synthesis or recombinant methods. Traces of the analog are not expected in people who never received it.
Filtering removes particulate matter that can block columns or scatter light. A 0.22 micrometre membrane is typical, and the filter material should be checked for peptide adsorption.