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Background And Receptor Pharmacology — Background and Details

By Editorial Desk · published 2026-06-22 · last reviewed 2026-08-01 · Guide

Everything below concerns nuclear receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.

Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.

Background and Receptor Pharmacology

SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms, lipid metabolism, and inflammatory gene expression. In cell and animal experiments, SR9009 alters transcription of clock-controlled genes and metabolic pathways. The compound is not a hormone and does not resemble classical steroid structures. Its activity depends on binding to the ligand-binding domain of REV-ERB, where it can modify corepressor recruitment.

Research interest in SR9009 grew from studies of circadian biology and metabolic disease. Preclinical reports describe effects on exercise capacity, muscle metabolism, and blood lipid levels in rodents, but these findings come from controlled laboratory settings. The compound has low oral bioavailability in animals, which limits systemic exposure after swallowing. Investigators often use injected routes in experiments to achieve measurable plasma concentrations. Human clinical data are sparse, no approved therapeutic product exists, and whether animal effects translate to humans remains an open question.

Analytical Detection and Stability

Stability depends on physical form, temperature, light exposure, and solvent. Solid SR9009 is generally stored cold and dry, with protection from light to limit degradation. Dimethyl sulfoxide stocks are common for laboratory work, but repeated freeze-thaw cycles can reduce compound integrity. Aqueous solutions may be less stable than organic stocks, and the ethyl ester in the structure can be susceptible to hydrolysis under certain conditions. Researchers typically validate storage conditions and recheck purity before quantitative experiments, especially when using archived material.

Regulatory treatment of SR9009 varies by country and region. It is not approved as a pharmaceutical, and several jurisdictions restrict its sale for human consumption. Some authorities classify it as a research chemical, a prescription-only substance, or a prohibited performance-enhancing agent in sport. Purchasers may encounter certificates of analysis, but these documents do not guarantee identity, purity, or legality. In research settings, institutional safety reviews and controlled procurement help ensure that materials are handled under appropriate oversight. The absence of harmonized rules means that legal status can change and requires verification.

Analytical identification of SR9009 typically relies on liquid chromatography coupled with tandem mass spectrometry. In biological samples, researchers first separate the compound from matrix components using protein precipitation, liquid-liquid extraction, or solid-phase extraction. High-performance liquid chromatography with ultraviolet detection and nuclear magnetic resonance spectroscopy can support structural confirmation of reference materials. Because SR9009 is a small, relatively lipophilic molecule, reverse-phase columns and acidic mobile phases are common. Laboratories often include isotope-labeled internal standards to improve quantification and to correct for ion suppression.

Sr9009 at a glance

PropertyValueNotes
Chemical classSynthetic REV-ERB agonistBinds REV-ERBα and REV-ERBβ in preclinical models
Molecular formulaC20H24ClN3O4SReported for the parent compound
CAS Registry Number1379686-30-2Common identifier in chemical databases
AppearanceOff-white to pale yellow solidTypical research chemical solid
SolubilitySoluble in DMSO and ethanol; low in waterClass: small organic molecule

SR9009 Background and Receptor Mechanism

Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.

SR9009 is a synthetic small molecule studied as an agonist of REV-ERB nuclear receptors. REV-ERB alpha and REV-ERB beta help regulate circadian rhythms and metabolic gene expression. In laboratory research, SR9009 has been used to probe how these receptors affect skeletal muscle, liver, and adipose tissue. The compound was identified in academic drug-discovery work and is often described in scientific literature by its chemical name and research code. It is not an approved medicine, and human clinical data remain limited or absent.

SR9009 binds REV-ERB receptors and alters their repressive activity on target genes. This action can change transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. In rodent studies, treated animals have shown changes in muscle oxidative capacity and exercise performance, though effects vary by dose, duration, and model. The precise molecular steps connecting receptor binding to whole-body outcomes are still an active area of investigation. Findings in animals do not automatically translate to humans.

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SR9009 Identity and Mechanism

SR9009 is frequently discussed alongside other REV-ERB ligands, including synthetic agonists and natural heme-related molecules. Its selectivity for REV-ERB over related nuclear receptors has been measured in binding and reporter assays, though off-target activity at higher concentrations is possible. The compound is prohibited in sport by the World Anti-Doping Agency, and it is not approved for any medical use in major jurisdictions. Products sold online may be labeled as research chemicals, and their identity and purity are not guaranteed by regulatory review.

SR9009 is a synthetic small molecule that acts on the nuclear receptors REV-ERBα and REV-ERBβ. These receptors are part of the circadian clock machinery and normally repress transcription of certain target genes. In laboratory research, SR9009 is used as a chemical tool to study how REV-ERB activity influences metabolism, inflammation, and daily biological rhythms. The compound is not an approved medicine, and its effects in humans remain largely uncharacterized. It is often described as an investigational agent rather than a therapeutic product.

Identity, Handling, and Regulation

Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.

Regulatory status varies by country and intended use. Major drug agencies have not granted marketing authorization for SR9009 as a medicine, and it is not listed as a controlled substance in many jurisdictions. It is often sold as a research chemical, a category that may fall outside pharmaceutical manufacturing rules. Buyers should verify local laws and supplier documentation, including certificates of analysis. The lack of standardized quality controls raises concerns about identity, purity, and actual content in products marketed online.

In laboratory settings, SR9009 is commonly identified by its molecular structure and its interaction with REV-ERB receptors. Vendors may list it under synonyms such as Stenabolic or REV-ERB agonist, but those names do not define purity or identity. Analytical confirmation typically uses high-performance liquid chromatography with ultraviolet detection or liquid chromatography–mass spectrometry. A reference standard is needed to compare retention time and mass spectrum, because the compound can be confused with related research chemicals.

Background and Mechanism of SR9009

SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.

SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.

Background from the literature

Prof. Ralser serves since 2019 as head of the Institute of Biochemistry at the Charité – Universitätsmedizin Berlin, Germany; as well as since 2022 as group leader at the University of Oxford, UK. He studied genetics and molecular biology in Salzburg, Austria. He completed his PhD in 2006 at the Max Planck Institute for Molecular Genetics in Berlin, Germany, studying neurodegenerative diseases. This was followed by a postdoctoral fellowship at the Vrije Universiteit Amsterdam, Netherlands, where he started to explore mass spectrometry. He returned to the MPI for Molecular Genetics in 2007 to become junior group leader, but in 2011 relocated his group to the University of Cambridge, UK. He relocated again, becoming group leader at the newly opened Francis Crick Institute in London in 2013 (senior group leader since 2019). His group moved to Oxford in 2022.

Pyocyanin inactivates catalase by reducing its gene’s transcription as well as directly targeting the enzyme itself. Glutathione is an important antioxidant modulated by pyocyanin. In particular the pool of the reduced form is depleted while the oxidised form is promoted by hydrogen peroxide which is not dismutated by catalase. In the cystic fibrosis lung, intracellular pyocyanin converts molecular oxygen to the superoxide free radical by oxidizing NADPH to NADP+. This has a doubly negative effect on the lungs. Firstly, the NADPH used by pyocyanin depletes the available substrate for the reaction catalysed by the NADPH oxidase enzyme. Secondly, the superoxide radical generated can inhibit cytokines, such as IL-4, IL-13 and IFN-γ, which usually upregulate NADPH oxidase. When the lung is confronted with pyocyanin, an increased concentration of catalase and superoxide dismutase is seen in order to deal with the barrage of radicals being produced.

1-DeoxySLs has a similar pattern to sphingolipids during de novo synthesis. The reaction is catalyzed by the enzyme serine palmitoyltransferase (SPT) but instead of condensing palmitoyl-CoA and L-serine, the amino acid substrate is replaced by L-alanina or L-glycine. This atypical sphingolipids are formed as the result of a mutated SPT (SPTLC1/SPTLC2) with alternative activities. It has also produced by wild-type of SPT under unfavorable conditions where the synthesis of L-serine is diminished and / or the biosynthesis of alanine and glycine is too high. The result of the reaction with L-alanine forms 1-deoxysphinganine (1-deoxySA; m18:0), while the use of glycerin forms 1-deoxymethylsphinganine (1-deoxymethylSA; m17:0). Both molecules are 1-deoxySLs.

== Nuclear fuel == Uranium-233 has been used as fuel in several reactor types and has been proposed for use in new designs. Uranium-233 can be bred in either fast reactors or thermal reactors, unlike the uranium-238-based fuel cycles which require the superior neutron economy of a fast reactor in order to breed plutonium, that is, to produce more fissile material than is consumed. In 1968, the Molten-Salt Reactor Experiment at Oak Ridge became the first reactor to operate on uranium-233. The long-term strategy of the nuclear power program of India, which has substantial thorium reserves, is to move to a nuclear program breeding uranium-233 from thorium feedstock.

Sources: en.wikipedia.org

Reference notes

=== Biochemistry === In solution, detergents help solubilize a variety of chemical species by dissociating aggregates and unfolding proteins. Popular surfactants in the biochemistry laboratory are sodium lauryl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Detergents are key reagents to extract protein by lysis of the cells and tissues: they disorganize the membrane's lipid bilayer (SDS, Triton X-100, X-114, CHAPS, DOC, and NP-40), and solubilize proteins. Milder detergents such as octyl thioglucoside, octyl glucoside or dodecyl maltoside are used to solubilize membrane proteins such as enzymes and receptors without denaturing them. Non-solubilized material is harvested by centrifugation or other means. For electrophoresis, for example, proteins are classically treated with SDS to denature the native tertiary and quaternary structures, allowing the separation of proteins according to their molecular weight. Detergents have also been used to decellularise organs. This process maintains a matrix of proteins that preserves the structure of the organ and often the microvascular network. The process has been successfully used to prepare organs such as the liver and heart for transplant in rats. Pulmonary surfactants are also naturally secreted by type II cells of the lung alveoli in mammals.

Ketamine has been found to increase dopaminergic neurotransmission in the brain, but instead of being due to dopamine reuptake inhibition, this may be via indirect/downstream mechanisms, namely through antagonism of the NMDA receptor. Whether ketamine is an agonist of D2 receptors is controversial. Early research by the Philip Seeman group found ketamine to be a D2 partial agonist with a potency similar to that of its NMDA receptor antagonism. However, later studies by different researchers found the affinity of ketamine of >10 μM for the regular human and rat D2 receptors, Moreover, whereas D2 receptor agonists such as bromocriptine can rapidly and powerfully suppress prolactin secretion, subanesthetic doses of ketamine have not been found to do this in humans and in fact, have been found to dose-dependently increase prolactin levels. Imaging studies have shown mixed results on inhibition of striatal [11C] raclopride binding by ketamine in humans, with some studies finding a significant decrease and others finding no such effect. However, changes in [11C] raclopride binding may be due to changes in dopamine concentrations induced by ketamine rather than binding of ketamine to the D2 receptor.

GHIH (somatostatin) from the periventricular nucleus circulating concentrations of GH and IGF-1 (negative feedback on the pituitary and hypothalamus) Hyperglycemia Glucocorticoids Dihydrotestosterone Phenothiazines In addition to control by endogenous and stimulus processes, a number of foreign compounds (xenobiotics such as drugs and endocrine disruptors) are known to influence GH secretion and function.

== Causes == Recent research has shown that autoimmune metaplastic atrophic gastritis (AMAG) is a result of the immune system attacking the parietal cells. Environmental metaplastic atrophic gastritis (EMAG) is due to environmental factors, such as diet and H. pylori infection. EMAG is typically confined to the body of the stomach. Patients with EMAG are also at increased risk of gastric carcinoma.

The rhodophyte, or red algae, group is a large and diverse lineage. Rhodophyte chloroplasts are also called rhodoplasts, literally "red chloroplasts". Rhodoplasts have a double membrane with an intermembrane space and phycobilin pigments organized into phycobilisomes on the thylakoid membranes, preventing their thylakoids from stacking. Some contain pyrenoids. Rhodoplasts have chlorophyll a and phycobilins for photosynthetic pigments; the phycobilin phycoerythrin is responsible for giving many red algae their distinctive red color. However, since they also contain the blue-green chlorophyll a and other pigments, many are reddish to purple from the combination. The red phycoerythrin pigment is an adaptation to help red algae catch more sunlight in deep water—as such, some red algae that live in shallow water have less phycoerythrin in their rhodoplasts, and can appear more greenish. Rhodoplasts synthesize a form of starch called floridean starch, which collects into granules outside the rhodoplast, in the cytoplasm of the red alga.

Sources: en.wikipedia.org

Notes from published material

== History == As a by-product of his work on type-specific staphylococcus antigens, Verwey reported in 1940 that a protein fraction prepared from extracts of these bacteria non-specifically precipitated rabbit antisera raised against different staphylococcus types. In 1958, Jensen confirmed Verwey's finding and showed that rabbit pre-immunization sera as well as normal human sera bound to the active component in the staphylococcus extract; he designated this component Antigen A (because it was found in fraction A of the extract) but thought it was a polysaccharide. The misclassification of the protein was the result of faulty tests, but it was not long thereafter (1962) that Löfkvist and Sjöquist corrected the error and confirmed that Antigen A was in fact a surface protein on the bacterial wall of certain strains of S. aureus. The Bergen group from Norway named the protein "Protein A" after the antigen fraction isolated by Jensen.

=== Advantages === Like iTDP, the main advantage of MSi-TDP is the capacity, within limits, to fully assess given proteoforms, including isotopic variants. Different front-end fractionation techniques can first be used to broadly resolve proteoforms (e.g. gel, LC, and capillary) in proteome extracts, enabling the subsequent MS/MS analysis of intact species to focus on those that are most compatible with the method (i.e. generally those <20-30 kDa). MSi-TDP can complement BUP approaches. Characterization of small proteins can be a significant challenge in BUP if an insufficient number of tryptic peptides are generated for analysis. MSi-TDP enables low mass protein detection, thus providing more detailed coverage of proteoforms in the lower MW range. Sequentially combining any number of fractionation techniques available to the researcher, such as chromatography (gel filtration and ion exchange), density-gradient ultrafiltration, or electrophoresis, dramatically increases the depth and quality of proteoform and proteome analysis.

=== pH stability === Sucrose esters are stable in the pH range of 4 to 8, so they can be used as an additive in most foods. At pH higher than 8, saponification (hydrolysis of the ester bond to release the original sucrose and the salt of fatty acids) might occur. Hydrolysis could also occur at pH lower than 4.

== Detecting peptides == Typically, peptide signals are detected at the MS1 level and distinguished from chemical noise through their characteristic isotopic pattern. These patterns are then tracked across the retention time dimension and used to reconstruct a chromatographic elution profile of the mono-isotopic peptide mass. The total ion current of the peptide signal is then integrated and used as a quantitative measurement of the original peptide concentration. For each detected peptide, all isotopic peaks are first found and the charge state is then assigned. Label-free quantification may be based on precursor signal intensity and has problems due to isolation interference: in high-throughput studies, the identity of the peptide precursor ion being measured could easily be a completely different peptide with a similar m/z ratio and which elutes in a time frame overlapping with that of the former peptide. Spectral counting has problems due to the fact that the peptides are identified, thus making it necessary to run an additional MS/MS scan which takes time and therefore reduces the resolution of the experiment.

It is the sedating ingredient of NyQuil (generally in combination with dextromethorphan and acetaminophen). In Commonwealth countries, such as Australia, Canada, South Africa, and the United Kingdom, doxylamine is available prepared with paracetamol (acetaminophen) and codeine under the brand name Dolased, Propain Plus, Syndol, or Mersyndol, as treatment for tension headache and other types of pain. Doxylamine succinate is used in general over-the-counter sleep-aids branded as Somnil (South Africa), Dozile, Donormyl, Lidène (France, Russian Federation), Dormidina (Spain, Portugal), Restavit, Unisom-2, Sominar (Thailand), Sleep Aid (generic, Australia), Dorminox (Poland) and Noctiben Mea (Slovenia). In the United States: Doxylamine succinate is the active ingredient in many over-the-counter sleep aids branded under various names. Doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclegis, approved by the FDA in April 2013 becoming the only drug approved for morning sickness with a class A safety rating for pregnancy (no evidence of risk). In Canada: Doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclectin, which is used to prevent morning sickness. It is also available in combination with vitamin B6 and folic acid under the brand name Evanorm (marketed by Ion Healthcare). In India Doxylamine preparations are available typically in combination with pyridoxine and may also contain folic acid. Doxylamine usage is thus restricted for pregnant women.

Sources: en.wikipedia.org

Frequently asked questions

What is SR9009?

SR9009 is a synthetic small molecule studied as an agonist of the REV-ERB nuclear receptors. It is not an approved medicine, and its effects in humans are not well characterized.

Is SR9009 a hormone?

No. It is a synthetic ligand that binds nuclear receptors, not a steroid or peptide hormone. Its activity depends on receptor binding rather than endocrine secretion.

What is known about human use?

Clinical evidence is limited. Most published data come from cell and animal experiments. Human safety and efficacy remain uncertain.

How is SR9009 measured in samples?

The most common approach is liquid chromatography-tandem mass spectrometry, often after extraction from blood, urine, or tissue. Ultraviolet detection and nuclear magnetic resonance spectroscopy are used mainly for reference material characterization. Isotope-labeled internal standards improve accuracy.

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