incretin is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-05-23. Numbers and descriptions here follow the published literature rather than marketing material.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | 31-amino-acid peptide | Modified glucagon-like peptide-1 analogue |
| Molecular mass | approximately 4114 Da | Calculated for the free peptide backbone |
| Appearance | white to off-white powder | Typical of purified lyophilised peptide batches |
| Solubility class | freely soluble in water | Aqueous solubility improves at slightly alkaline pH |
| Typical storage | -20 degrees Celsius, dry, dark | Protect from repeated freeze-thaw cycles |
=== Memory === Receptor activation is linked to impairing multiple memory processes, including working memory, spatial learning, and fear memory consolidation, by inhibiting synaptic plasticity such as long-term potentiation (LTP) in regions like the amygdala and hippocampus. In models of amnesia, endogenous receptor activation leads to reactivation of memory traces, prolonging retention latency in inhibitory avoidance tasks, with antagonism often protecting against stress-induced deficits. Receptor activation by dynorphins also reduces the intensity of the emotional aspect of memories.
The first-generation vaccines are manufactured by growing live vaccinia virus in the skin of live animals. Most first-generation vaccines are calf lymph vaccines that were grown on the skin of cows, but other animals were also used, including sheep. The development of freeze-dried vaccine in the 1950s made it possible to preserve vaccinia virus for long periods of time without refrigeration, leading to the availability of freeze-dried vaccines such as Dryvax. The vaccine is administered by multiple puncture of the skin (scarification) with a bifurcated needle that holds vaccine solution in the fork. The skin should be cleaned with water rather than alcohol, as the alcohol could inactivate the vaccinia virus. If alcohol is used, it must be allowed to evaporate completely before the vaccine is administered. Vaccination results in a skin lesion that fills with pus and eventually crusts over. This manifestation of localized vaccinia infection is known as a vaccine "take" and demonstrates immunity to smallpox. After 2–3 weeks, the scab will fall off and leave behind a vaccine scar. First generation vaccines consist of live, unattenuated vaccinia virus. One-third of first-time vaccinees develop side effects significant enough to miss school, work, or other activities, or have difficulty sleeping. 15–20% of children receiving the vaccine for the first time develop fevers of over 102 °F (39 °C). The vaccinia lesion can transmit the virus to other people. Rare side effects include postvaccinal encephalitis and myopericarditis.
[H3SO4]+[HSO4]− = 2.7 × 10−4 The corresponding equilibrium constant for water, Kw is 10−14, a factor of 1010 (10 billion) smaller. In spite of the viscosity of the acid, the effective molar conductivities of the H3SO+4 and HSO−4 ions are high due to an intramolecular proton-switch mechanism (analogous to the Grotthuss mechanism in water), making sulfuric acid a good conductor of electricity.
United Nations Security Council Resolution 283 was passed in June 1970 calling for all UN member states to close, or refrain from establishing, diplomatic or consular offices in South West Africa. The resolution also recommended disinvestment, boycotts, and voluntary sanctions of that territory as long as it remained under South African rule. In light of these developments, the Security Council sought the advisory opinion of the ICJ on the "legal consequences for states of the continued presence of South Africa in Namibia". There was initial opposition to this course of action from SWAPO and the OAU, because their delegates feared another inconclusive ruling like the one in 1966 would strengthen South Africa's case for annexation. Nevertheless, the prevailing opinion at the Security Council was that since the composition of judges had been changed since 1966, a ruling in favour of the nationalist movement was more likely. At the UN's request, SWAPO was permitted to lobby informally at the court and was even offered an observer presence in the courtroom itself. On 21 June 1971, the ICJ reversed its earlier decision not to rule on the legality of South Africa's mandate, and expressed the opinion that any continued perpetuation of said mandate was illegal. Furthermore, the court found that Pretoria was under obligation to withdraw its administration immediately and that if it failed to do so, UN member states would be compelled to refrain from any political or business dealings which might imply recognition of the South African government's presence there.
=== Vaccine manufacturers === The companies with the highest market share in vaccine production are Merck, Sanofi, GlaxoSmithKline, Pfizer and Novartis, with 70% of vaccine sales concentrated in the EU or US as of 2013. Vaccine manufacturing plants require large capital investments ($50 million up to $300 million) and may take between 4 and 6 years to construct, with the full process of vaccine development taking between 10 and 15 years. Manufacturing in developing countries is playing an increasing role in supplying these countries, specifically with regards to older vaccines and in Brazil, India and China. The manufacturers in India are the most advanced in the developing world and include the Serum Institute of India, one of the largest producers of vaccines by number of doses and an innovator in processes, recently improving efficiency of producing the measles vaccine by 10 to 20-fold, due to switching to a MRC-5 cell culture instead of chicken eggs. China's manufacturing capabilities are focused on supplying their own domestic need, with Sinopharm (CNPGC) alone providing over 85% of the doses for 14 different vaccines in China. Brazil is approaching the point of supplying its own domestic needs using technology transferred from the developed world.
Sources: en.wikipedia.org
A stability diagram may be generated by calculating the matrix trace for each axis over a defined range of q and a values. The stability diagram of a square wave is very similar to that of the traditional harmonic quadrupole field. Having the additional parameter d in the waveform, the digital ion trap can perform certain experiments which are not available in the conventional harmonic wave RF ion trap. One example is the digital asymmetric wave isolation which is the method of using a d value around 0.6 to narrow the mass range to isolate a precursor ion. The DIT is a versatile instrument because it is capable of operating at constant AC voltage without a DC offset for any conceivable duty cycle and frequency. The dynamic frequency does not impose a limit on the mass range. The Mathieu space stability diagram of the linear and 3D DIT change with duty cycle. When a = 0 there will be a finite range of stable q values for each quadrupole axis that will depend on the duty cycle. Fig 3 (a) shows a Mathieu space stability diagram for the duty cycle d = 0.50 of a linear DIT. The horizontal line indicates where the parameter a = 0. The range of completely stable q values appear where this line passes through the green colored region; it ranges from q = 0 to roughly q = 0.7125. The blue colored areas in the figure depict stability along the x-axis only. Yellow colored regions depict stability along the y-axis only.
== The cladistic turn (1970s–1990s) == By the late 20th century lichen systematics adopted the quantitative, computer-aided methods gaining ground across biology. Numerical taxonomy (phenetics) and cladistics entered lichenology, paralleling their uptake in plant and animal studies. Researchers replaced qualitative judgement with data matrices that coded morphological, chemical, and anatomical characters, then applied algorithms to infer relationships. Phenetic studies of the 1970s grouped lichens with clustering routines; in the 1980s Willi Hennig's cladistics shifted focus to shared-derived characters (synapomorphies) for reconstructing evolutionary trees. The shift required clear definitions of characters and explicit decisions about which traits were primitive or derived. Analyses became repeatable and easy to update as new characters or taxa were added. Robert Lücking (2020) called this methodological turn a milestone on par with the invention of the microscope for taxonomy. The new methods added rigour and standardization, aligning lichen systematics with broader evolutionary biology. Manuals on numerical and cladistic techniques were widely adopted, and phylogenetic workshops became regular features of lichen conferences. Cladistic rigour prompted a reassessment of single-trait classifications. Earlier systems frequently anchored families or genera on a single trait—spore septation, a particular metabolite, and so on. Cladistic analyses showed that such one-character groupings often masked true relationships.
Eculizumab (Soliris) appears to be useful for atypical hemolytic uremic syndrome (aHUS). In September 2011 the U.S. Food and Drug Administration (FDA) approved it as an orphan drug to treat people with aHUS. This approval was based on two small prospective trials of 17 people and 20 people. In the UK, NICE issued guidance on the use of Eculizumab for treating aHUS, based on five evidence sources, including those used by the FDA No randomised controlled trials were identified. All prospective studies were phase 2, open‑label, non‑randomised, single‑arm studies that included patients with different clinical baseline characteristics. The prospective studies lasted 26 weeks; however, patients were allowed to continue treatment with eculizumab in a long‑term extension study. Ravulizumab-cwvz (Ultomiris) is a second generation monoclonal antibody for aHUS made by Alexion pharmaceuticals, Inc. The target of ravulizumab-cwvz is the same eculizumab (Soliris) with changes to the structure of the antibody resulting in a longer serum half life and therefore reduced dosing regimen.
Uranium-235 makes up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature. Uranium-235 has a half-life of 704 million years. It was discovered in 1935 by Arthur Jeffrey Dempster. Its fission cross section for slow thermal neutrons is about 584.3±1 barns. For fast neutrons it is on the order of 1 barn. At thermal energy levels, about 5 of 6 neutron absorptions result in fission and 1 of 6 result in neutron capture forming uranium-236. The fission-to-capture ratio improves for faster neutrons.
Glibenclamide, also known as glyburide (U.S. English), is an antidiabetic medication used to treat type 2 diabetes. It is recommended that it be taken together with diet and exercise. It may be used with other antidiabetic medication. It is not recommended for use by itself in type 1 diabetes. It is taken by mouth. Common side effects include nausea and heartburn. Serious side effects may include angioedema and low blood sugar. It is generally not recommended during pregnancy but can be used during breastfeeding. It is in the sulfonylureas class of medications and works by increasing the release of insulin from the pancreas. Glibenclamide was discovered in 1969 and approved for medical use in the United States in 1984. It is available as a generic medication. In 2021, it was the 214th most commonly prescribed medication in the United States, with more than 2 million prescriptions.
Sources: en.wikipedia.org
It is a glucagon-like peptide-1 receptor agonist, often grouped with the incretin mimetics. Its backbone is modified from the human hormone to resist enzymatic degradation and to bind albumin. These two features distinguish it from the native peptide.
No. It shares high sequence identity but carries non-natural modifications that alter its stability and clearance. The naturally occurring hormone is broken down within minutes, while the synthetic analogue circulates far longer.
Attachment to serum albumin reduces renal filtration of the peptide and shields it from enzymatic breakdown. The consequence is a much longer interval between administrations than unmodified peptides allow. The precise contribution of binding affinity to overall duration is still being quantified.
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.