If you have been reading about circadian rhythm 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.
Updated 2026-05-19. Numbers and descriptions here follow the published literature rather than marketing material.
Detection of SR9009 in biological samples usually employs liquid chromatography coupled with tandem mass spectrometry. This method can identify the parent compound and sometimes metabolites in urine or blood. Because exposure can be low and clearance may be rapid, sample timing and limits of detection matter. Laboratories validate assays for sensitivity and specificity. Results are interpreted alongside chain-of-custody and quality-control records. Urine is the common matrix for anti-doping analysis, while blood may be used in research settings.
Handling recommendations for SR9009 in a laboratory setting include storing the solid at low temperature, protected from light and moisture. The compound is often dissolved in dimethyl sulfoxide or ethanol for experiments. Solutions should be prepared with appropriate personal protective equipment and disposed of according to local rules. Stability data for long-term storage are limited, so stock solutions are typically kept cold and used within defined periods. Records of preparation date and concentration support reproducibility.
SR9009 is not approved as a medicine by major regulatory agencies. It is commonly sold as a research chemical, a category that may fall outside customary drug approval and quality rules. In sports, the World Anti-Doping Agency lists SR9009 as a prohibited substance. Athletes who use it can face sanctions if it is detected in a sample. Legal status varies by country, and importation may be restricted. Enforcement practices differ across borders.
Laboratory identification of SR9009 typically relies on chromatographic separation coupled to mass spectrometry, often with ultraviolet detection as a secondary check. Nuclear magnetic resonance spectroscopy can confirm molecular structure when a reference standard is available. Because many suppliers sell the compound as a research chemical, independent identity testing is important for experimental reproducibility. A single retention time is not sufficient proof of identity, especially when related compounds may be present. Purity assessments usually report a percentage based on area normalization.
SR9009 is generally described as poorly soluble in water and more soluble in organic solvents such as dimethyl sulfoxide and ethanol. Stock solutions are commonly prepared in an organic solvent before dilution into an aqueous buffer or vehicle. Precipitation can occur if the organic fraction is reduced too quickly or if the final concentration exceeds the compound's solubility limit. Sonication or gentle warming may aid dissolution in some protocols, but excessive heat can promote degradation. Container material and pH can also influence observed solubility.
For long-term storage, SR9009 is typically kept as a solid at low temperature, protected from moisture and light. Desiccated conditions limit hydrolysis, while opaque containers reduce photochemical breakdown. Solutions are less stable than solids and are often stored frozen in aliquots to avoid repeated freeze-thaw cycles. Stability data are not standardized across all suppliers, so users should rely on certificate-of-analysis information when available. Degradation may appear as color change, precipitate, or decreased chromatographic purity.
| Property | Value | Notes |
|---|---|---|
| Regulatory status | Not approved as a medicine in major jurisdictions | Sold as a research chemical; legal status varies |
| Anti-doping status | Prohibited by the World Anti-Doping Agency | Listed under non-approved substances or related category |
| Typical analytical method | LC-MS/MS | Used for detection and confirmation in biological samples |
| Storage temperature | −20 °C or lower for solid | Desiccated and protected from light |
| Common solution solvents | DMSO; ethanol | Aqueous solubility is limited |
Preclinical reports have linked SR9009 to improved endurance and altered energy expenditure in rodents. Such findings have prompted interest in whether REV-ERB activation can influence skeletal muscle metabolism. However, the reported effects depend on dose, route, and experimental model, and replication across laboratories is limited. Human trials have not established comparable outcomes, so claims about exercise performance remain speculative. The absence of controlled human data is a central limitation in interpreting these observations.
The mechanism of action involves binding to REV-ERB receptors and recruiting corepressor complexes, which represses target gene transcription. This contrasts with many nuclear receptor agonists that activate transcription. Downstream effects may include changes in autophagy, mitochondrial biogenesis, and lipid handling, but the precise pathways remain an active area of study. Whether these molecular events translate into meaningful physiological effects in humans is unresolved. Most evidence comes from cultured cells and rodent models rather than human participants.
SR9009 is a synthetic small molecule developed as an agonist of the nuclear receptors REV-ERBα (NR1D1) and REV-ERBβ (NR1D2). These receptors help regulate circadian rhythms and metabolic gene expression. In cell and animal studies, SR9009 alters transcription of genes involved in lipid metabolism, inflammation, and mitochondrial function. It is not an approved medicine, and its pharmacological profile in humans remains largely uncharacterized. The compound is frequently discussed in the context of circadian biology and metabolic research rather than clinical use.
Laboratory studies often administer SR9009 by injection because oral absorption appears poor in rodents. Reported pharmacokinetic properties include rapid metabolism and low systemic exposure after oral dosing. Human pharmacokinetic data are sparse, so absorption, distribution, metabolism, and excretion in people are not well defined. Some research explores related REV-ERB compounds with improved drug-like properties. Regulatory approval for any REV-ERB agonist as a human medicine has not been granted to date.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ, also called NR1D1 and NR1D2. These receptors help regulate circadian rhythms and metabolic gene programs. The compound was developed for laboratory research, not as an approved therapeutic. Its identity is distinct from steroid hormones and selective androgen receptor modulators. Scientific interest centers on how REV-ERB activation changes gene expression in cells and animal models.
At the molecular level, SR9009 binds the ligand-binding domain of REV-ERB and strengthens recruitment of corepressor proteins such as NCoR and HDAC3. This increases repression of target genes, including Bmal1 and other clock-controlled and metabolic genes. In rodent studies, such changes have been linked to altered lipid handling, glucose metabolism, and energy expenditure. The precise chain of events between receptor binding and whole-body effects remains an active area of research. Findings in animals do not automatically translate to humans.
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.
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.
== Legacy == David Lipman, director of the National Center for Biotechnology Information, has called Dayhoff the "mother and father of bioinformatics". Her seminal contributions as the mother of the science of bioinformatics, now routinely used as part of the process for naming bacteria, were acknowledged with a bacterium being named after her in 2020, Enemella dayhoffiae. Dayhoff was inducted into the Maryland Women's Hall of Fame in March 2026.
=== Homeostasis === Almost all cells have a sodium–potassium pump transporting sodium ions out and potassium ions in, maintaining a balance in a narrow range of concentrations essential to cell function. This internal homeostasis mechanism requires an external homeostasis mechanism to maintain the concentration of potassium ions in plasma in the intercellular space. External homeostasis is primarily provided by the kidneys.
=== Huntington's disease === Huntington's disease is a hyperkinetic movement basal ganglia disease caused by lack of normal inhibitory inputs from medium spiny neurons of the basal ganglia. This poses the opposite effects of those associated with Parkinson's disease, including inappropriate activation of upper motor neurons. As with the GABAergic mechanisms observed in relation to Parkinson's disease, a GABA agonist injected into the substantia nigra pars reticulata decreases inhibition of upper motor neurons, resulting in ballistic involuntary motor movements, similar to symptoms of Huntington's disease.
Sources: en.wikipedia.org
== Signs and symptoms == Initially, the symptoms of biliary atresia are indistinguishable from those of neonatal jaundice, a usually harmless condition commonly seen in infants. However, infants with biliary atresia develop progressive conjugated jaundice, pale white stools, dark urine, and an enlarged palpable liver. Some infants fail to thrive as there will be a degree of fat and fat-soluble vitamin malabsorption (e.g. Vitamin K). This may cause a bleeding tendency. Eventually, and usually after 2 months, cirrhosis with portal hypertension will develop. If left untreated, biliary atresia can lead to liver failure. Unlike other forms of jaundice, however, biliary-atresia-related cholestasis mostly does not result in kernicterus, a form of brain damage resulting from liver dysfunction. This is because in biliary atresia, the liver, although diseased, is still able to conjugate bilirubin, and conjugated bilirubin is unable to cross the blood–brain barrier.
The most complex RPR synthesized by that point was called 24-3, which was newly capable of polymerizing the sequences of a substantial variety of nucleotide sequences and navigating through complex secondary structures of RNA substrates inaccessible to previous ribozymes. In fact, this experiment was the first to use a ribozyme to synthesize a tRNA molecule. Starting with the 24-3 ribozyme, Tjhung et al. applied another fourteen rounds of selection to obtain an RNA polymerase ribozyme by in vitro evolution termed '38-6' that has an unprecedented level of activity in copying complex RNA molecules. However, this ribozyme is unable to copy itself and its RNA products have a high mutation rate. In a subsequent study, the researchers began with the 38-6 ribozyme and applied another 14 rounds of selection to generate the '52-2' ribozyme, which compared to 38-6, was again many times more active and could begin generating detectable and functional levels of the class I ligase, although it was still limited in its fidelity and functionality in comparison to copying of the same template by proteins such as the T7 RNA polymerase. An RPR called t5(+1) adds triplet nucleotides at a time instead of just one nucleotide at a time. This heterodimeric RPR can navigate secondary structures inaccessible to 24-3, including hairpins. In the initial pool of RNA variants derived only from a previously synthesized RPR known as the Z RPR, two sequences separately emerged and evolved to be mutualistically dependent on each other.
While American slaves in the Antebellum South were sold for around $40,000 (in inflation adjusted dollars), a slave nowadays can be bought for just $90, making replacement more economical than providing long-term care. Slavery is a multibillion-dollar industry with estimates of up to $35 billion generated annually.
== E-government == In the United Nations E-Government Survey 2018, Thailand was ranked 73 of 193 nations (1=best) in the provision of digital services to citizens. Other ASEAN nations were ranked: Singapore, 7; Malaysia, 48; Brunei, 59; Philippines, 75; Vietnam, 88; Indonesia, 107; Cambodia, 145; Myanmar, 157; Laos, 162.
Sources: en.wikipedia.org
These large protein complexes may act as spacers between the sheets of stromal thylakoids. The number of thylakoids and the total thylakoid area of a chloroplast is influenced by light exposure. Shaded chloroplasts contain larger and more grana with more thylakoid membrane area than chloroplasts exposed to bright light, which have smaller and fewer grana and less thylakoid area. Thylakoid extent can change within minutes of light exposure or removal.
== Career == D'Abo made her screen debut in the low-budget science fiction horror film Xtro (1982), playing Analise Mercier, a French au pair, who becomes a human incubator for an alien. She appeared in the film Until September (1984) and had small roles in television mini-series based on Sidney Sheldon's novels Master of the Game (1984) and If Tomorrow Comes. She also appeared in Oscar winner Taylor Hackford's film White Nights (1985) and in an uncredited role as a woman pouring champagne to Klaus Maria Brandauer at a hunting party in the Oscar winning Out of Africa (1985), directed by Oscar winner Sydney Pollack. Other credits include Arthur the King (1985). She worked on the French stage in Lyon playing Varinia in Spartacus directed by Jacques Weber in 1981, played Roxane in Cyrano de Bergerac at the Grenier de Toulouse in 1982, then worked in a 1987 French TV movie, Les Idiots (The Idiots), written by Gérard Brach, with Jean Carmet and Jean-Pierre Marielle. D'Abo had a starring role in The Living Daylights (1987) as Kara Milovy, the sweet and vulnerable Czechoslovak cellist and would-be sniper who falls for James Bond. As a tie-in with the film, she also appeared in a Bond-themed Playboy cover and multi-page pictorial in the September 1987 issue, but later said in an interview with People magazine that "I wouldn't do those pictures now... I've learned a lot since then". She featured in the music video to the 1987 single 'So the Story Goes' by British band Living in a Box.
Per Baseball Reference, Bagwell's 79.6 Wins Above Replacement (WAR) ranks sixth-most all-time among first basemen, trailing only Lou Gehrig, Albert Pujols, Jimmie Foxx, Cap Anson, and Roger Connor. He spent the first nine seasons of his career (1991–99) playing home games at the Astrodome, notorious for its reputation as the toughest park in which to hit when baseball was still played there. However, during those nine years, his production at home was nearly identical to his production on the road. In that same period of time, his 160 OPS+ was fourth behind Bonds, McGwire, and Frank Thomas; his 56.7 WAR was third behind Bonds and Ken Griffey Jr. From 1994 to 2000, a span including his age-26 through age-32 seasons, he averaged 41 home runs and 41 doubles per 162 games while batting .309, .433 OBP, and .593 SLG for a 167 OPS+. Over his career, Bagwell batted at least .300 six times, amassed a 1.000 OPS five times, collected at least 30 home runs eight times, 100 RBI eight times, 100 runs scored nine times, and 100 walks seven times. He is the only player in history to achieve six consecutive seasons (1996–2001) with each of 30 home runs, 100 RBI, 100 runs scored, and 100 walks. Bagwell had seven seasons with 30 home runs and 100 walks; the only players with more are Gehrig, Ruth, Williams, Jim Thome, and Thomas. Bagwell is one of 12 players in MLB history to hit at 400 home runs and attain a career on-base percentage of at least .400. The only National League first baseman to reach the 30–30 club, he is the only first baseman in history to do it twice.
==== General indications ==== Doxycycline is a broad-spectrum antibiotic that is employed in the treatment of numerous bacterial infections. The drug is effective against bacteria such as Moraxella catarrhalis (a cause of respiratory tract infections), Brucella melitensis (a cause of brucellosis), Chlamydia pneumoniae (a cause of atypical pneumonia), and Mycoplasma pneumoniae (a cause of pneumonia). Additionally, doxycycline is used in the prevention and treatment of serious conditions like anthrax, leptospirosis, bubonic plague, and Lyme disease. However, some bacteria have developed resistance to doxycycline, including Haemophilus species, Mycoplasma hominis, and Pseudomonas aeruginosa. Specifically, doxycycline is indicated for treatment of the following diseases:
coli bacteria stores proteins and pyrophosphates in its periplasmic membrane until either are needed within the cell. Recent advancement in phosphoproteomic identification has resulted in the discoveries of countless phosphorylation sites in proteins. This required an integrative medium for accessible data in which known phosphorylation sites of proteins are organized. A curated database of dbPAF was created, containing known phosphorylation sites in H. sapiens, M. musculus, R. norvegicus, D. melanogaster, C. elegans, S. pombe and S. cerevisiae. The database currently holds 294,370 non-redundant phosphorylation sites of 40,432 proteins. Other tools of phosphorylation prediction in proteins include NetPhos for eukaryotes, NetPhosBac for bacteria, and ViralPhos for viruses.
Sources: en.wikipedia.org
Its legal status depends on the country and intended use. It is not an approved medicine in major jurisdictions. In sport, it is prohibited by anti-doping rules.
Laboratories typically use LC-MS/MS to detect SR9009 and related compounds in urine or blood. The method is sensitive but depends on sample collection timing. Confirmatory analysis follows quality-control procedures.
Solid material is generally kept cold, dry, and protected from light. Solutions are often stored in sealed containers at low temperature. Stability beyond recommended periods is not well documented.
Liquid chromatography with mass spectrometry is a common approach. Ultraviolet detection and nuclear magnetic resonance can support identification when suitable standards are available.