This is a working overview of GLP-1 receptor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-01-24 and is reviewed periodically as new material appears.
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.
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 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。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | Peptide backbone with a C18 fatty diacid side chain |
| Molecular weight | Approximately 4113 Da | Consistent with a 31-residue peptide plus linker |
| Appearance | White to off-white powder | Lyophilized solid; hygroscopic if left open |
| Solubility class | Sparingly soluble to soluble in water | Varies with pH and ionic strength |
| Typical analytical method | Reversed-phase HPLC with UV detection | Often paired with mass spectrometry for identity |
关于降解产物的免疫原性风险，文献中仍有讨论空间。体外聚集水平与临床免疫反应之间的定量关系尚未确立。多数公开研究只报告理化指标，缺少长期随访的对应数据。这一问题在生物类似物比对中尤其受到关注。
市售注射用制剂通常要求在二至八摄氏度冷藏保存，并避免光照与冻结。部分多剂量笔在首次使用后允许在不超过三十摄氏度的环境中存放有限周数，具体期限由辅料与防腐剂体系决定。反复冻融会促进肽链聚集并改变可见颗粒计数，因此应予避免。冻干粉末在干燥、避光、低温条件下更为稳定。溶液配制后宜使用低吸附容器，以减少肽类在塑料或玻璃表面的损失。
纯度评价多采用反相高效液相色谱，流动相常加入三氟乙酸或甲酸作为离子对改性剂，检测波长设在二百一十四纳米或二百二十纳米。分子量确认依靠电喷雾电离质谱或基质辅助激光解吸电离质谱，实测值应与理论值在数 ppm 内吻合。肽图分析通过酶切后液相色谱串联质谱完成，用于核查序列与修饰位点。体积排阻色谱用于定量共价与非共价聚集体。生物基质浓度测定则采用免疫分析或液相色谱串联质谱。
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.
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.
Reversed-phase high-performance liquid chromatography is widely used to assess purity and to separate the parent peptide from related substances. Mass spectrometry confirms identity and can resolve modifications that differ by a few daltons. Size-exclusion chromatography detects dimers and higher aggregates, which are relevant to both stability and immunogenicity questions. Peptide mapping with enzymatic digestion locates specific modifications along the sequence. Circular dichroism provides a secondary-structure profile, although it gives limited information about local conformational changes.
Quality control for peptide material focuses on identity, purity, content and the profile of impurities. Common degradants include deamidated and oxidised forms, plus aggregates formed during storage or handling. Forced degradation studies under heat, light, acid and peroxide help define which conditions accelerate change and which analytical methods detect it. Limits for individual impurities are set by pharmacopoeial monographs or manufacturer specifications. How much a given impurity affects biological activity is often uncertain, and conclusions may depend on the assay used.
===== Ophthalmological use ===== Cocaine eye drops have traditionally been used by neurologists when examining people suspected of having Horner syndrome. In Horner syndrome, sympathetic innervation to the eye is blocked. In a healthy eye, cocaine stimulates the sympathetic nervous system (SNS) by inhibiting norepinephrine reuptake, causing the pupil to dilate. In patients with Horner syndrome, sympathetic innervation to the eye is disrupted, so the affected pupil does not dilate in response to cocaine and remains constricted, or dilates to a lesser extent than the unaffected eye, which also receives the eye drop test. If both eyes dilate equally, the patient does not have Horner syndrome. However, apraclonidine has largely replaced cocaine as the first-line pharmacologic agent for the diagnosis of Horner syndrome in routine clinical practice.
=== Metabolic disorder === People with diabetes were found to have an increased concentration of ketones, the cause of sweet urine smell, derived from the oxidation of non-esterified fatty acids. Exhaled acetone is often used as a biomarker, but its relevance as a sole biomarker for diabetes is ambiguous. Acetone is considered a biomarker in other diseases, such as lung cancer and cystic fibrosis (CF), and reports on acetone and blood glucose have been mixed. Maple syrup urine disease, characterized by a strong maple syrup scent in urine, is found to have higher keto acid levels.
== Medical uses == Subcutaneous and intramuscular injections are generally more effective than the nasal spray and can be self-administered by patients. Intravenous injection is considered very effective for severe migraine or status migrainosus. Dihydroergotamine is also used in the treatment of medication overuse headache. Dihydroergotamine is indicated for the acute treatment of migraine.
Sources: en.wikipedia.org
=== Approximate solution === Approximate polynomial-time algorithms for structural alignment that produce a family of "optimal" solutions within an approximation parameter for a given scoring function have been developed. Although these algorithms theoretically classify the approximate protein structure alignment problem as "tractable", they are still computationally too expensive for large-scale protein structure analysis. As a consequence, practical algorithms that converge to the global solutions of the alignment, given a scoring function, do not exist. Most algorithms are, therefore, heuristic, but algorithms that guarantee the convergence to at least local maximizers of the scoring functions, and are practical, have been developed.
=== Chemical engineering === GC–MS is used for the analysis of unknown organic compound mixtures. One critical use of this technology is the use of GC–MS to determine the composition of bio-oils processed from raw biomass. GC–MS is also utilized in the identification of continuous phase component in a smart material, magnetorheological (MR) fluid.
Phosphate analysis reveals high concentrations of cremations in the barrows, in the form of satellite and secondary burials in the round barrows. This suggests that the primary burials may have been of chiefs, or socially powerful/respected people, and that some people may have paid to be buried close to the person they respected or followed.
Sources: en.wikipedia.org
== Growth hormone deficiency == In a study of children with growth hormone deficiency, ibutamoren performed better than other growth hormone secretagogues at improving growth hormone levels. An ongoing study compares ibutamoren directly to injectable hGH in terms of height velocity in this population. Topline data from Phase 2 OraGrowtH210 and OraGrowtH212 Trials of LUM-201 in PGHD met all primary and secondary endpoints.
== Human rights abuses == Throughout the transitional period, the Transitional Government of Ethiopia was criticized by various human rights organizations for abuses ranging from extrajudicial executions to unlawful detentions. At the establishment of the TGE in 1991, when the EPRDF first took power, human rights organizations such as Human Rights Watch and Amnesty International expressed optimism about the future of the state of human rights in Ethiopia. During the previous regime under Mengistu, human rights groups could not exist; following May 1991, however, human rights watchdogs such as the Ethiopian Human Rights Council, the Ethiopian Congress for Democrats, and the human rights committee of the Committee of Eleven were established. However, hopes were quickly dashed following a pattern of rights violations aimed at political dissidents across the country. For instance, at least ten demonstrators in Addis Ababa were killed while protesting the EPRDF in their early days of power. In addition, an estimated 5,000-100,000+ members (including jailed former soldiers) of the previous PDRE were swiftly imprisoned under the TGE. While some were later released, many others were held without being officially charged or having a trial. Members of Mengistu's Workers' Party of Ethiopia were also not permitted to travel abroad or go back to work if they were previously detained by the EPRDF for the duration of the year, but generally found themselves able to do so in 1992.
==== Eight principles of diagnosis ==== The process of determining which actual pattern is on hand is called 辩证 (biàn zhèng, usually translated as "pattern diagnosis", "pattern identification" or "pattern discrimination"). Generally, the first and most important step in pattern diagnosis is an evaluation of the present signs and symptoms on the basis of the "Eight Principles" (八纲; bā gāng). These eight principles refer to four pairs of fundamental qualities of a disease: exterior/interior, heat/cold, vacuity/repletion, and yin/yang. Out of these, heat/cold and vacuity/repletion have the biggest clinical importance. The yin/yang quality, on the other side, has the smallest importance and is somewhat seen aside from the other three pairs, since it merely presents a general and vague conclusion regarding what other qualities are found. In detail, the Eight Principles refer to the following:
Sources: en.wikipedia.org
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.
Structural modifications, including a fatty acid side chain and non-natural amino acid substitutions, slow enzymatic breakdown and promote albumin binding. These changes support once-weekly dosing rather than twice-daily administration.
The pathways involving insulin, glucagon, gastric emptying, and appetite signaling are well described. How much each pathway contributes to weight reduction in a given person is not fully established.
差别集中在三处：第 8 位残基被非天然氨基酸取代，第 34 位换成精氨酸，第 26 位增加一条脂肪酸侧链。前两处改动降低酶解速率，侧链则通过白蛋白结合延长循环时间。综合结果是半衰期从约两分钟延长到约一周。