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Background And Receptor Pharmacology — What the Evidence Shows

By Editorial Desk · published 2025-07-15 · last reviewed 2025-08-21 · Topic

A practical reference on LC-MS/MS: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.

This page was last updated on 2025-08-21 and is reviewed periodically as new material appears.

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.

Regulatory and sporting contexts treat SR9009 as a prohibited substance in many elite competitions. Its presence on banned lists reflects concerns about performance enhancement and unknown long-term safety. Analytical chemists have developed methods to detect the parent compound and its metabolites in urine and blood. Literature discussions distinguish between in vitro potency, animal pharmacology, and anecdotal human reports. The latter are difficult to verify because products sold online may lack purity or contain different compounds.

Analytical Detection and Storage

Storage recommendations for SR9009 reference material typically specify a freezer at -20 °C or lower, with protection from moisture and light. Repeated freeze-thaw cycles can degrade small molecules and introduce variability. Stock solutions in dimethyl sulfoxide are often aliquoted to avoid repeated handling. Stability studies may examine degradation under heat, humidity, and light exposure. The compound's thiophene and nitro groups can participate in reactions that alter analytical signals over time, so such changes affect quantitative results.

Quality control for research materials includes identity confirmation by nuclear magnetic resonance and purity assessment by high-performance liquid chromatography. Mass spectrometry provides molecular weight confirmation and can detect related impurities. Purchasers should request a certificate of analysis that lists lot-specific data. Online products advertised for human use often lack such documentation. Distinguishing legitimate research material from mislabeled or contaminated samples is a recurring challenge in independent testing, and independent laboratories may use orthogonal methods to verify identity.

Detection of SR9009 in biological samples usually relies on liquid chromatography coupled to tandem mass spectrometry. This approach separates the compound from matrix components and identifies it by mass transitions. Because SR9009 can undergo metabolism, laboratories often look for both parent drug and specific metabolites. Sample preparation may involve protein precipitation or solid-phase extraction. Method validation examines sensitivity, carryover, and interference from related substances, and reference standards are required for accurate calibration.

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

Background and Mechanism

SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not an approved medicine and has no established human therapeutic use. The compound appears in scientific literature as a tool for probing circadian and metabolic regulation. Online sellers often label it as a research chemical, sometimes using the nickname Stenabolic. Its chemical identity is distinct from selective androgen receptor modulators, stimulants, and peroxisome proliferator-activated receptor delta agonists. Researchers use it mainly in cell and animal experiments.

At the molecular level, SR9009 binds REV-ERBα and REV-ERBβ and alters their repressive activity on target genes. These nuclear receptors help regulate the circadian clock, lipid synthesis, glucose metabolism, and inflammatory pathways. By changing transcription, the compound can shift the timing or magnitude of downstream metabolic processes in model systems. It does not act through androgen receptors or adenosine receptors, which distinguishes it from several substances sold for athletic performance. Whether the same transcriptional changes occur in humans at tolerable exposures remains an open question because controlled human studies are lacking.

Preclinical reports describe effects on exercise endurance, mitochondrial content, and lipid profiles in rodents, but these findings come from specific experimental conditions. Many studies use high doses or delivery methods that may not translate directly to human use. SR9009 has been reported to have low oral bioavailability and a short half-life, which complicates interpretation of oral dosing studies. It is not established as safe or effective for any indication. Literature discussions often separate its pharmacological mechanism from unverified claims made in fitness and supplement markets.

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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.

Notes from published material

2.A.1 Major Facilitator superfamily (MFS), see also Lactose permease, Phosphate permease and Glucose transporter 2.A.2 The Glycoside-Pentoside-Hexuronide (GPH):Cation Symporter Family 2.A.3 The Amino Acid-Polyamine-Organocation (APC) Family 2.A.4 Cation diffusion facilitator (CDF) Family 2.A.5 Zinc (Zn2+)-Iron (Fe2+) Permease Family 2.A.6 Resistance-Nodulation-Cell Division Superfamily, see also SecDF protein-export membrane protein 2.A.7 The Drug/Metabolite Transporter (DMT) Superfamily 2.A.8 The Gluconate:H+ Symporter (GntP) Family 2.A.9 The Membrane Protein Insertase (YidC/Alb3/Oxa1) Family 2.A.10 The 2-Keto-3-Deoxygluconate Transporter (KdgT) Family 2.A.11 The Citrate-Mg2+:H+ (CitM) Citrate-Ca2+:H+ (CitH) Symporter (CitMHS) Family 2.A.12 ATP:ADP Antiporter Family 2.A.13 The C4-Dicarboxylate Uptake (Dcu) Family 2.A.14 Lactate Permease Family 2.A.15 The Betaine/Carnitine/Choline Transporter (BCCT) Family 2.A.16 Tellurite-resistance/Dicarboxylate Transporter Family 2.A.17 Proton-dependent Oligopeptide Transporter Family 2.A.18 The Amino Acid/Auxin Permease (AAAP) Family 2.A.19 The Ca2+:Cation Antiporter (CaCA) Family 2.A.20 The Inorganic Phosphate Transporter (PiT) Family 2.A.21 Solute:Sodium Symporter Family 2.A.22 The Neurotransmitter:Sodium Symporter Family 2.A.23 The Dicarboxylate/Amino Acid:Cation (Na+ or H+) Symporter (DAACS) Family 2.A.24 The 2-Hydroxycarboxylate Transporter (2-HCT) Family 2.A.25 Alanine or Glycine:Cation Symporter (AGCS) Family 2.A.26 The Branched Chain Amino Acid:Cation Symporter (LIVCS) Family 2.A.27 The Glutamate:Na+ Symporter (ESS) Family 2.A.28 Bile Acid:Na+ Symporter Family 2.A.29 Mitochondrial carrier Family 2.A.30 Cation-Chloride Cotransporter (CCC) Family 2.A.31 Anion Exchanger Family 2.A.32 The Silicon Transporter (Sit) Family 2.A.33 NhaA Na+:H+ Antiporter (NhaA) Family 2.A.34 The NhaB Na+:H+ Antiporter (NhaB) Family 2.A.35 The NhaC Na+:H+ Antiporter (NhaC) Family 2.A.36 Monovalent Cation:Proton Antiporter-1 (CPA1) Family 2.A.37 Monovalent Cation:Proton Antiporter-2 (CPA2) Family 2.A.38 K+ Transporter (Trk) Family 2.A.39 Nucleobase:Cation Symporter-1 (NCS1) Family 2.A.40 Nucleobase:Cation Symporter-2 (NCS2) Family 2.A.41 The Concentrative Nucleoside Transporter (CNT) Family 2.A.42 The Hydroxy/Aromatic Amino Acid Permease (HAAAP) Family 2.A.43 The Lysosomal Cystine Transporter (LCT) Family 2.A.45 Arsenite-Antimonite Efflux Family 2.A.46 The Benzoate:H+ Symporter (BenE) Family 2.A.47 Divalent Anion:Na+ Symporter (DASS) Family 2.A.48 The Reduced Folate Carrier (RFC) Family 2.A.49 Chloride Carrier/Channel (ClC) Family 2.A.50 The Glycerol Uptake (GUP) Family 2.A.51 The Chromate Ion Transporter (CHR) Family 2.A.52 The Ni2+-Co2+ Transporter (NiCoT) Family 2.A.53 Sulfate permease (SulP) Family 2.A.54 The Mitochondrial Tricarboxylate Carrier (MTC) Family 2.A.55 The Metal Ion (Mn2+-iron) Transporter (Nramp) Family 2.A.56 The Tripartite ATP-independent Periplasmic Transporter (TRAP-T) Family 2.A.57 The Equilibrative Nucleoside Transporter (ENT) Family 2.A.58 The Phosphate:Na+ Symporter (PNaS) Family 2.A.59 The Arsenical Resistance-3 (ACR3) Family 2.A.60 Organo Anion Transporter (OAT) Family 2.A.61 The C4-dicarboxylate Uptake C (DcuC) Family 2.A.62 The NhaD Na+:H+ Antiporter (NhaD) Family 2.A.63 The Monovalent Cation (K+ or Na+):Proton Antiporter-3 (CPA3) Family 2.A.64 Twin Arginine Targeting (Tat) Family 2.A.65 The Bilirubin Transporter (BRT) Family 2.A.66 The Multidrug/Oligosaccharidyl-lipid/Polysaccharide (MOP) Flippase Superfamily 2.A.67 The Oligopeptide Transporter (OPT) Family 2.A.68 The p-Aminobenzoyl-glutamate Transporter (AbgT) Family 2.A.69 The Auxin Efflux Carrier (AEC) Family 2.A.70 The Malonate:Na+ Symporter (MSS) Family 2.A.71 The Folate-Biopterin Transporter (FBT) Family 2.A.72 The K+ Uptake Permease (KUP) Family 2.A.73 The Short Chain Fatty Acid Uptake (AtoE) Family 2.A.74 The 4 TMS Multidrug Endosomal Transporter (MET) Family 2.A.75 The L-Lysine Exporter (LysE) Family 2.A.76 The Resistance to Homoserine/Threonine (RhtB) Family 2.A.77 The Cadmium Resistance (CadD) Family 2.A.78 The Branched Chain Amino Acid Exporter (LIV-E) Family 2.A.79 The Threonine/Serine Exporter (ThrE) Family 2.A.80 The Tricarboxylate Transporter (TTT) Family 2.A.81 The Aspartate:Alanine Exchanger (AAEx) Family 2.A.82 The Organic Solute Transporter (OST) Family 2.A.83 The Na+-dependent Bicarbonate Transporter (SBT) Family 2.A.84 The Chloroplast Maltose Exporter (MEX) Family 2.A.85 The Aromatic Acid Exporter (ArAE) Family 2.A.86 The Autoinducer-2 Exporter (AI-2E) Family (Formerly the PerM Family, TC #9.B.22) 2.A.87 The Prokaryotic Riboflavin Transporter (P-RFT) Family 2.A.88 Vitamin Uptake Transporter (VUT or ECF) Family 2.A.89 The Vacuolar Iron Transporter (VIT) Family 2.A.90 Vitamin A Receptor/Transporter (STRA6) Family 2.A.91 Mitochondrial tRNA Import Complex (M-RIC) (Formerly 9.C.8) 2.A.92 The Choline Transporter-like (CTL) Family 2.A.94 The Phosphate Permease (Pho1) Family 2.A.95 The 6TMS Neutral Amino Acid Transporter (NAAT) Family 2.A.96 The Acetate Uptake Transporter (AceTr) Family 2.A.97 The Mitochondrial Inner Membrane K+/H+ and Ca2+/H+ Exchanger (LetM1) Family 2.A.98 The Putative Sulfate Exporter (PSE) Family 2.A.99 The 6TMS Ni2+ uptake transporter (HupE-UreJ) Family 2.A.100 The Ferroportin (Fpn) Family 2.A.101 The Malonate Uptake (MatC) Family (Formerly UIT1) 2.A.102 The 4-Toluene Sulfonate Uptake Permease (TSUP) Family 2.A.103 The Bacterial Murein Precursor Exporter (MPE) Family 2.A.104 The L-Alanine Exporter (AlaE) Family 2.A.105 The Mitochondrial Pyruvate Carrier (MPC) Family 2.A.106 The Ca2+:H+ Antiporter-2 (CaCA2) Family 2.A.107 The MntP Mn2+ Exporter (MntP) Family 2.A.108 The Iron/Lead Transporter (ILT) Family 2.A.109 The Tellurium Ion Resistance (TerC) Family 2.A.110 The Heme Transporter, heme-responsive gene protein (HRG) Family 2.A.111 The Na+/H+ Antiporter-E (NhaE) Family 2.A.112 The KX Blood-group Antigen (KXA) Family 2.A.113 The Nickel/cobalt Transporter (NicO) Family 2.A.114 The Putative Peptide Transporter Carbon Starvation CstA (CstA) Family 2.A.115 The Novobiocin Exporter (NbcE) Family 2.A.116 The Peptidoglycolipid Addressing Protein (GAP) Family 2.A.117 The Chlorhexadine Exporter (CHX) family 2.A.118 The Basic Amino Acid Antiporter (ArcD) Family 2.A.119 The Organo-Arsenical Exporter (ArsP) Family 2.A.120 The Putative Amino Acid Permease (PAAP) Family 2.A.121 The Sulfate Transporter (CysZ) Family 2.A.122 The LrgB/CidB holin-like auxiliary protein (LrgB/CidB) Family 2.A.123 The Sweet; PQ-loop; Saliva; MtN3 (Sweet) Family 2.A.124 The Lysine Exporter (LysO) Family 2.A.125 The Eukaryotic Riboflavin Transporter (E-RFT) Family 2.A.126 The Fatty Acid Exporter (FAX) Family 2.A.127 Enterobacterial Cardiolipin Transporter (CLT) Family

MHC class II can be conditionally expressed by all cell types, but normally occurs only on "professional" antigen-presenting cells (APCs): macrophages, B cells, and especially dendritic cells (DCs). An APC takes up an antigenic protein, performs antigen processing, and returns a molecular fraction of it—a fraction termed the epitope—and displays it on the APC's surface coupled within an MHC class II molecule (antigen presentation). On the cell's surface, the epitope can be recognized by immunologic structures like T-cell receptors (TCRs). The molecular region which binds to the epitope is the paratope. On surfaces of helper T cells are CD4 receptors, as well as TCRs. When a naive helper T cell's CD4 molecule docks to an APC's MHC class II molecule, its TCR can meet and bind the epitope coupled within the MHC class II. This event primes the naive T cell. According to the local milieu, that is, the balance of cytokines secreted by APCs in the microenvironment, the naive helper T cell (Th0) polarizes into either a memory Th cell or an effector Th cell of phenotype either type 1 (Th1), type 2 (Th2), type 17 (Th17), or regulatory/suppressor (Treg), as so far identified, the Th cell's terminal differentiation. MHC class II thus mediates immunization to—or, if APCs polarize Th0 cells principally to Treg cells, immune tolerance of—an antigen.

DAD discovered in Gram-negative E. coli B membrane can convert L-amino acids into D-amino acids as well. Additionally, D-amino acid dehydrogenase is used in dye-linked dehydrogenase (dye-DHs) which uses artificial dyes such as 2,6-dichloroindophenol (DCIP) as their electron acceptor rather than using their natural electron acceptors. This can accelerate the reaction between the enzyme and the substrate when the electrons are being transferred.

Signs and symptoms of methemoglobinemia (methemoglobin level above 10%) include shortness of breath, cyanosis, mental status changes (~50%), headache, fatigue, exercise intolerance, dizziness, and loss of consciousness. People with severe methemoglobinemia (methemoglobin level above 50%) may exhibit seizures, coma, and death (level above 70%). Healthy people may not have many symptoms with methemoglobin levels below 15%. However, people with co-morbidities such as anemia, cardiovascular disease, lung disease, sepsis, or who have abnormal hemoglobin species (e.g. carboxyhemoglobin, sulfhemoglobinemia or sickle hemoglobin) may experience moderate to severe symptoms at much lower levels (as low as 5–8%).

Sources: en.wikipedia.org

Further detail

== Further reading == Hagedorn, Henry H.; Kunkel, Joseph G. (1979). "Vitellogenin and Vitellin in Insects". Annual Review of Entomology. 24 (4): 475–505. doi:10.1146/annurev.en.24.010179.002355. Wheeler, Diana E.; Kawooya, John K. (1990). "Purification and characterization of honey bee vitellogenin". Archives of Insect Biochemistry and Physiology. 14 (4): 253–267. doi:10.1002/arch.940140405. PMID 2134180. "Vitellogenin Gene Expression in Male Fathead Minnow as an Indicator of Exposure to Endocrine Disrupting Chemicals (EDC) in an Aquatic Environment". EPA.gov. 2006. Amdam, G. V.; Norberg, K.; Omholt, S. W.; Kryger, P.; Lourenço, A. P.; Bitondi, M. M. G.; Simões, Z. L. P. (November 2005). "Higher vitellogenin concentrations in honey bee workers may be an adaptation to life in temperate climates". Insectes Sociaux. 52 (4): 316–319. doi:10.1007/s00040-005-0812-2. S2CID 25197924. Seehuus, S.-C.; Norberg, K.; Gimsa, U.; Krekling, T.; Amdam, G. V. (17 January 2006). "Reproductive protein protects functionally sterile honey bee workers from oxidative stress". Proceedings of the National Academy of Sciences. 103 (4): 962–7. doi:10.1073/pnas.0502681103. PMC 1347965. PMID 16418279. Nelson, C. Mindy; Ihle, Kate E; Fondrk, M. Kim; Page, Robert E; Amdam, Gro V; Chittka, Lars (6 March 2007). "The Gene vitellogenin Has Multiple Coordinating Effects on Social Organization". PLOS Biology. 5 (3): e62. doi:10.1371/journal.pbio.0050062. PMC 1808115. PMID 17341131. Corona, M.; Velarde, R. A.; Remolina, S.; Moran-Lauter, A.; Wang, Y.; Hughes, K. A.; Robinson, G. E. (16 April 2007).

=== Video games === Liches are prominent in the Might and Magic series of video games, appearing primarily as enemies, but also as playable characters in several installments. They are equally prevalent in the spin-off series Heroes of Might and Magic, where they appear in most installments as recruitable creatures, but also as heroes. One of the most prolific liches in New World Computing's old continuity was Sandro, appearing in many titles and referenced in many more. The primary antagonist of Heroes of Might and Magic III: Restoration of Erathia is also a lich: the former king of Erathia raised by necromancers. The Baldur's Gate series of video games includes several liches, as powerful but optional boss fights. Warcraft III and World of Warcraft: Wrath of the Lich King features the continent of Northrend, the realm of the eponymous Lich King and his undead minions. Arthas Menethil, also known as the Lich King, one of the most prominent antagonists in Warcraft lore, appears as a raid boss in the Wrath of the Lich King expansion, as well as a playable character in the crossover video game Heroes of the Storm. In the Dota series of video games, Lich is one of the playable heroes. In League of Legends, the champion Karthus embraced the gift of death and became a lich. In the video game Enter the Gungeon, a lich is the final boss located in Bullet Hell. In Dragon Age: The Veilguard, companion Emmrich Volkarin can become a lich.

== Discovery == German chemist Felix Ehrlich discovered isoleucine while studying the composition of beet-sugar molasses 1903. In 1907 Ehrlich carried out further studies on fibrin, egg albumin, gluten, and beef muscle in 1907. These studies verified the natural composition of isoleucine. Ehrlich published his own synthesis of isoleucine in 1908.

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?

Liquid chromatography-tandem mass spectrometry is a common approach. It can detect the parent compound and its metabolites in biological matrices.

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