1. Introduction: The ERβ Discovery & WAY-200070 Development
Estrogen receptor beta (ERβ) was discovered in 1996 by Kuiper et al., revealing a previously unknown dimension of estrogen signaling that differed fundamentally from the classical estrogen receptor alpha (ERα) pathway. This discovery opened an entirely new field of pharmacological research — one in which the selective activation of ERβ could deliver therapeutic benefits without the proliferative and feminizing side effects associated with ERα activation.
WAY-200070 emerged from the medicinal chemistry laboratories at Wyeth Research as part of a systematic program to develop aryl diphenolic azoles as potent and selective ERβ ligands. First described by Malamas et al. in the Journal of Medicinal Chemistry (2004), WAY-200070 quickly established itself as the gold-standard ERβ agonist — a position it retains to this day in research laboratories worldwide.
💡 At a Glance
WAY-200070 (CAS 440122-66-7) is a synthetic, non-steroidal, highly selective agonist of estrogen receptor beta (ERβ) with 68-fold selectivity over ERα (EC50 = 2 nM vs. 155 nM). It enhances serotonergic and dopaminergic neurotransmission, produces antidepressant- and anxiolytic-like effects, and demonstrates significant antidiabetic and potential anticancer activity in preclinical models.
What makes WAY-200070 particularly valuable is its clean pharmacological profile: it is inactive in classic estrogen action assays such as uterotrophic and osteopenia tests, does not affect luteinizing hormone (LH) or follicle-stimulating hormone (FSH), and does not inhibit ovulation. This means researchers can isolate ERβ-mediated pathways with minimal confounding from ERα-driven effects — a critical requirement for producing publication-grade data in modern endocrinology and neuroscience research.
2. Chemical Profile & Basic Information
WAY-200070 belongs to the aryl diphenolic azole chemotype — a structural class specifically designed by Wyeth's medicinal chemistry team to exploit the subtle differences in the ligand-binding domains of ERα and ERβ. The benzoxazole core provides the key scaffold for ERβ selectivity, while the bromine substituent and phenolic hydroxyl groups contribute to high-affinity binding.
🧪 Chemical Identity Card
| Product Name | WAY-200070 |
| CAS Number | 440122-66-7 |
| Synonyms | WAY200070; WAY 200070; 7-Bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol; 7-bromo-2-(4-hydroxyphenyl)-5-benzoxazolol |
| IUPAC Name | 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol |
| Molecular Formula | C13H8BrNO3 |
| Molecular Weight | 306.11 g/mol |
| SMILES | Oc1ccc(cc1)-c2nc3cc(O)cc(Br)c3o2 |
| InChIKey | BAAILVWEAXFTSF-UHFFFAOYSA-N |
| Appearance | White to beige solid powder |
| Purity | ≥98% (HPLC) |
| Originator | Wyeth Research |
| XLogP | 3.15 (favorable brain penetration) |
2.1 Solubility Profile
Understanding the solubility of WAY-200070 across different solvents is critical for preparing stock solutions and dosing formulations:
| Solvent | Solubility | Notes |
|---|---|---|
| DMSO | ≥20 mg/mL | Recommended for stock solutions |
| DMF | 33 mg/mL | Alternative for high-concentration stocks |
| Ethanol | 33 mg/mL | Useful for in vivo vehicle preparation |
| Ethanol:PBS (pH 7.2) (1:20) | 0.04 mg/mL | Aqueous working solution |
⚠️ Storage Note
Store WAY-200070 dry, dark, and at 2–8°C for short-term use (days to weeks) or −20°C for long-term storage (months to years). Protect from moisture and light. DMSO stock solutions should be aliquoted and stored at −80°C for up to 6 months; avoid repeated freeze-thaw cycles.
3. Molecular Mechanism of Action
WAY-200070 exerts its biological effects through highly selective binding to the ligand-binding domain (LBD) of ERβ, triggering a cascade of molecular events that distinguish it sharply from non-selective estrogenic compounds.
3.1 ERβ Binding & Nuclear Translocation
Upon binding to ERβ (EC50 = 2 nM), WAY-200070 induces rapid nuclear translocation of the receptor from the cytosol. In the landmark study by Hughes et al. (2008), this translocation was observed within 15 minutes of subcutaneous administration at 30 mg/kg in wild-type mice — and critically, this effect was completely absent in ERβ knockout (ERβKO) mice, confirming ERβ-specific action.
3.2 Downstream Signaling: c-fos Activation
Following nuclear translocation, WAY-200070 triggers c-fos activation — a marker of neuronal activation — at 4 hours post-administration, but not at 15 minutes. This delayed activation pattern is consistent with genomic estrogen receptor signaling, where the ligand-receptor complex acts as a transcription factor to modulate gene expression.
3.3 Neurotransmitter Modulation
One of the most well-characterized pharmacological actions of WAY-200070 is its modulation of monoamine neurotransmitters:
- Dopamine: A delayed ~50% increase in striatal dopamine, significant from 90 to 240 minutes post-administration (30 mg/kg s.c.). This effect was absent in ERβKO mice.
- Serotonin (5-HT): A delayed and transient ~100% increase in serotonin levels in wild-type mice.
- 5-HTP Accumulation: ERβKO mice showed reduced frontal cortex 5-HTP levels, indicating reduced tryptophan hydroxylase activity — further supporting the role of ERβ in serotonergic regulation.
📖 Key Reference
Hughes ZA, Liu F, Platt BJ, et al. "WAY-200070, a selective agonist of estrogen receptor beta as a potential novel anxiolytic/antidepressant agent." Neuropharmacology. 2008;54(7):1136–1142. PMID: 18423777.
3.4 Pancreatic β-Cell Mechanism
In the endocrine pancreas, WAY-200070 triggers a distinct mechanism: ERβ activation leads to closure of ATP-sensitive K+ (KATP) channels in pancreatic β-cells, enhancing glucose-induced [Ca2+] oscillations and promoting insulin release cooperatively with glucose. This rapid, non-genomic action complements the genomic effects observed in the central nervous system.
4. Key Advantages of WAY-200070 as a Research Probe
4.1 Unmatched ERβ Selectivity
With a 68-fold selectivity window (EC50 2 nM vs. 155 nM for ERα), WAY-200070 allows researchers to confidently attribute observed effects to ERβ activation rather than off-target ERα activity. This is particularly critical when studying tissues expressing both receptor subtypes, such as the brain, breast, and pancreas.
4.2 Stereochemical Uniformity
Unlike the alternative ERβ agonist DPN (diarylpropionitrile), which is supplied as a racemic mixture where only the S-enantiomer is highly active, WAY-200070 is a single, stereochemically uniform molecule. This eliminates batch-to-batch variability and the need for costly enantiomer separation.
⚠️ Racemic Risk with DPN
Substituting WAY-200070 with DPN introduces critical experimental confounds: the R-enantiomer of DPN is largely inactive at ERβ, meaning that effective concentrations must account for the racemic ratio. This leads to higher required doses and potential off-target toxicity from the inactive enantiomer.
4.3 Brain Penetration
With an XLogP of 3.15, WAY-200070 demonstrates favorable blood-brain barrier (BBB) penetration — essential for neuroscience research targeting central ERβ pathways. The compound reaches pharmacologically relevant concentrations in the striatum, frontal cortex, and other key brain regions.
4.4 Clean Endocrine Profile
WAY-200070 does not affect LH, FSH, or ovulation, and is inactive in uterotrophic and osteopenia assays. This means researchers can study ERβ-specific effects without confounding from hypothalamic-pituitary-gonadal axis suppression or proliferative effects on reproductive tissues.
4.5 Rich Literature Foundation
WAY-200070 has been cited in dozens of peer-reviewed publications across neuroscience, endocrinology, and oncology. This extensive literature base provides researchers with well-validated protocols, dosing regimens, and control strategies — reducing the time and cost of experimental optimization.
4.6 Validated Across Multiple Disease Models
From depression and anxiety to diabetes, breast cancer, asthma, and visceral pain — WAY-200070 has been tested in a remarkable range of preclinical models, making it one of the most versatile ERβ research tools available.
5. Preclinical Research Applications
5.1 Depression & Anxiety Research
WAY-200070 produces robust antidepressant-like and anxiolytic-like effects in multiple behavioral models, establishing ERβ as a promising target for mood disorder therapeutics:
| Behavioral Model | Dose | Route | Key Finding |
|---|---|---|---|
| Tail Suspension Test | 30 mg/kg | s.c. | ↓ Immobility time (antidepressant-like) |
| Four-Plate Test | 30 mg/kg | s.c. | ↑ Punished crossings (anxiolytic-like) |
| Stress-Induced Hyperthermia | 30 mg/kg | s.c. | Attenuated hyperthermic response |
| Forced Swim Test | 10 mg/kg | s.c. | ↓ Depressive-like behaviors |
| Open-Field Test | 10 mg/kg | s.c. | ↓ Anxiety-like behaviors |
| Elevated Plus Maze | 10 mg/kg | s.c. | ↓ Anxiety-like behaviors |
| Zebrafish Light/Dark Choice | — | — | Anxiolytic-like effects confirmed |
5.2 Diabetes & Metabolic Research
One of the most striking findings in WAY-200070 research is its potent antidiabetic activity. In the seminal study by Alonso-Magdalena et al. (Diabetes, 2013), WAY-200070 demonstrated multiple beneficial metabolic effects:
- In vitro: Enhanced glucose-stimulated insulin secretion (GSIS) in both mouse and human islets
- Acute in vivo: Single administration increased plasma insulin and improved glucose tolerance
- Chronic (2-week): Increased glucose-induced insulin release, improved insulin sensitivity, and expanded pancreatic β-cell mass
- STZ-nicotinamide model: Significant improvement in plasma insulin, glucose tolerance, and β-cell mass regeneration
- db/db mice: Restored first-phase insulin secretion and enhanced β-cell mass
- GLP-1 pathway: Improved glucose tolerance via increased plasma GLP-1 levels
✅ Key Finding
WAY-200070 enhanced insulin secretion only at stimulatory glucose concentrations (8–16 mmol/L), not at basal glucose (3 mmol/L) — a critical safety feature suggesting low hypoglycemia risk in therapeutic applications.
5.3 Breast Cancer & Oncology Research
Since ERα (not ERβ) is implicated in breast development and proliferation, selective ERβ activation offers a unique therapeutic window in oncology. WAY-200070 has been shown to:
- Augment the efficacy of tamoxifen in in vitro breast cancer models
- Potentially suppress breast growth through ERβ-mediated antiproliferative signaling
- Provide a safe profile for both premenopausal and postmenopausal women (no LH/FSH suppression, no ovulation inhibition)
5.4 Visceral Pain Research
WAY-200070 (10 mg/kg s.c.) produced significant attenuation of the visceromotor response in a rat pain model, demonstrating that ERβ activation may modulate visceral pain perception — a finding with implications for irritable bowel syndrome (IBS) and other functional pain disorders.
5.5 Asthma & Airway Inflammation
In a mixed allergen (MA)-induced asthma model, sustained-release WAY-200070 (4.17 mg/day s.c.) significantly reversed airway hyperresponsiveness, decreased compliance, and airway remodeling — with more pronounced effects in female mice, suggesting a sex-dependent ERβ-mediated protective mechanism.
5.6 Social Behavior & Cognition
WAY-200070 has demonstrated effects on social behavior in mice:
- Increased agonistic behaviors (pushing down, aggressive grooming) without affecting attacks
- Enhanced social learning of food preferences in ovariectomized mice (two-fold prolongation)
- Social learning effects contrasted with ERα agonist PPT, which abolished social preference learning
6. WAY-200070 vs. Alternative ERβ Agonists: Selection Guide
Researchers choosing an ERβ agonist face a critical decision that directly impacts data quality and reproducibility. The following comparison highlights why WAY-200070 remains the preferred choice for publication-grade research:
| Parameter | WAY-200070 | DPN | 17β-Estradiol |
|---|---|---|---|
| ERβ EC50 | 2 nM | ~5 nM (S-enantiomer) | ~0.1 nM |
| ERα EC50 | 155 nM | ~200 nM | ~0.1 nM |
| Selectivity (ERβ/ERα) | 68-fold | ~40-fold (S-only) | ~1-fold (non-selective) |
| Stereochemistry | Single molecule | Racemic mixture | Single molecule |
| Batch Consistency | Excellent | Variable (enantiomeric ratio) | Excellent |
| Uterotrophic Activity | Inactive | Minimal | Active |
| HPG Axis Suppression | None | Minimal | Yes |
| Brain Penetration | Yes (XLogP 3.15) | Yes | Yes |
| Ideal Use Case | Gold-standard ERβ research | Budget screening | Non-selective estrogen studies |
✅ Selection Rule of Thumb
For any study where ERβ selectivity is the central question, choose WAY-200070. Use DPN only for preliminary dose-ranging screens where cost is the primary constraint, and always confirm key findings with WAY-200070. Never substitute with 17β-estradiol for ERβ-specific studies — its non-selective binding will confound results with ERα-driven proliferative effects.
7. Experimental Dosing & Administration Guide
The following dosing protocols are compiled from peer-reviewed publications and represent the most validated regimens for WAY-200070 across different research applications:
| Application | Species/Model | Dose | Route | Vehicle |
|---|---|---|---|---|
| Neurochemistry (DA/5-HT) | C57BL/6 mice (WT & ERβKO) | 30 mg/kg | s.c. | 10% EtOH / 90% miglyol |
| Tail Suspension Test | C57BL/6 mice | 3–30 mg/kg | s.c. | 10% EtOH / 90% miglyol |
| Four-Plate Test | C57BL/6 mice | 30 mg/kg | s.c. | 10% EtOH / 90% miglyol |
| Stress-Induced Hyperthermia | C57BL/6 mice | 30 mg/kg | s.c. | 10% EtOH / 90% miglyol |
| Forced Swim / Open Field / EPM | Ovariectomized mice | 10 mg/kg | s.c. | 27% HPBCD in saline |
| Social Learning | Ovariectomized rats | 2 mg/kg/day | s.c. | 27% HPBCD in saline |
| Glucose Tolerance (acute) | C57BL/6 mice | 10 mg/kg | i.p. | — |
| Glucose Tolerance (chronic) | Ovariectomized mice | 10 mg/kg/day | s.c. | — |
| Visceral Pain | SD rats (OVX & intact) | 10 mg/kg | s.c. | — |
| Asthma (sustained release) | C57BL/6J mice | 4.17 mg/day | s.c. implant | Slow-release pellet |
| Diabetes (STZ model) | Mice | 10 mg/kg | i.p. | — |
⚠️ IACUC & Ethical Considerations
All animal studies using WAY-200070 must be approved by your Institutional Animal Care and Use Committee (IACUC) or equivalent ethics board. Include ERβ knockout (ERβKO) mice as negative controls to confirm ERβ-specific effects. Vehicle-treated wild-type littermates should serve as the primary control group.
📝 Recommended Control Compounds
Include the following controls in your experimental design: (1) Vehicle-only group, (2) ERβ antagonist (e.g., PHTPP) to confirm receptor specificity, (3) ERβKO animals (genetic control), and (4) Optional: ERα agonist (PPT) for receptor subtype comparison.
8. Target Research Fields & User Groups
WAY-200070 is primarily used by the following research communities:
| Research Field | Primary Applications | Typical Model Systems |
|---|---|---|
| Neuroscience / Psychopharmacology | Mood disorders, anxiety, dopamine/serotonin regulation | C57BL/6 mice, ERβKO mice, zebrafish |
| Endocrinology / Metabolism | Diabetes, insulin secretion, β-cell biology, GLP-1 | Mouse/human islets, db/db mice, STZ models |
| Oncology | Breast cancer, tamoxifen combination, antiproliferation | MCF-7, T47D cell lines, in vitro models |
| Pain Research | Visceral pain, functional pain disorders | Ovariectomized rats, visceromotor response |
| Pulmonary / Immunology | Asthma, airway remodeling, inflammation | Mixed allergen mouse model |
| Behavioral Science | Social behavior, social learning, agonistic behavior | Ovariectomized mice and rats |
| Drug Discovery / Screening | HTS campaigns, lead optimization, target validation | Cell-based ERβ reporter assays |
9. Product Specifications & Quality Parameters
| Parameter | Specification |
|---|---|
| Product Name | WAY-200070 |
| CAS Number | 440122-66-7 |
| Molecular Formula | C13H8BrNO3 |
| Molecular Weight | 306.11 g/mol |
| Purity | ≥98% (HPLC) |
| Appearance | White to beige solid powder |
| Solubility | DMSO: ≥20 mg/mL; DMF: 33 mg/mL; Ethanol: 33 mg/mL |
| Storage | 2–8°C (short term); −20°C (long term); dry, dark |
| MDL Number | MFCD16618385 |
| PubChem CID | 135418373 |
9.1 Safety & Handling
⚠️ Safety Information
GHS Classification: GHS06 (Danger)
Hazard Statements: H301 (Toxic if swallowed), H319 (Causes serious eye irritation)
Precautionary Statements: P264 (Wash hands thoroughly after handling), P280 (Wear eye protection), P301+P310 (IF SWALLOWED: Immediately call a POISON CENTER), P305+P351+P338 (IF IN EYES: Rinse cautiously with water for several minutes)
WGK: 3 (highly water endangering)
9.2 Pack Sizes
Standard pack sizes include 5 mg, 10 mg, 25 mg, and 50 mg. Bulk quantities and custom synthesis are available upon request. All batches ship with full Certificate of Analysis (COA), including HPLC purity data, NMR spectra, and mass spectrometry confirmation.
10. Frequently Asked Questions
WAY-200070 exhibits 68-fold selectivity for ERβ over ERα (EC50 = 2 nM vs. 155 nM), with well-characterized in vivo profiles including sustained dopamine increase and anxiolytic effects. Its unique aryl diphenolic azole chemotype and stereochemical uniformity make it irreplaceable for reproducible, publication-grade ERβ research.
DPN (diarylpropionitrile) is typically supplied as a racemic mixture where only the S-enantiomer is highly active, introducing batch-to-batch variability. WAY-200070 provides a single, stereochemically uniform molecule with consistent 68-fold ERβ selectivity, ensuring absolute assay reproducibility without enantiomer separation.
The most validated dose is 30 mg/kg subcutaneous injection for neurochemistry and behavioral studies (tail suspension, four-plate test). For metabolic studies, 10 mg/kg intraperitoneal or subcutaneous is commonly used. Vehicle options include 10% ethanol/90% miglyol or 27% hydroxypropyl betacyclodextran in saline.
No. Due to its ERβ selectivity, WAY-200070 does not affect luteinizing hormone (LH) or follicle-stimulating hormone (FSH), does not inhibit ovulation, and does not suppress the hypothalamic-pituitary-gonadal axis. It is also inactive in uterotrophic and osteopenia assays.
Yes. WAY-200070 has demonstrated significant antidiabetic effects including enhanced glucose-stimulated insulin secretion, improved glucose tolerance, increased pancreatic β-cell mass, and restored first-phase insulin secretion in db/db mice. It has been validated in STZ-nicotinamide-induced diabetic mouse models.
Store at 2-8°C for short-term use (days to weeks) or -20°C for long-term storage (months to years). Keep dry and protected from light. The compound is soluble in DMSO (≥20 mg/mL), DMF (33 mg/mL), and ethanol (33 mg/mL). Use GHS06 safety precautions as it is toxic if swallowed (H301) and causes eye irritation (H319).
No. WAY-200070 is a research chemical intended exclusively for laboratory and preclinical research. It has not been approved by the FDA or any regulatory authority for human therapeutic use. All content on this page is for research and educational purposes only.
11. Conclusion
WAY-200070 remains the definitive research tool for dissecting ERβ-mediated pathways across neuroscience, endocrinology, and oncology. Its 68-fold selectivity, stereochemical uniformity, clean endocrine profile, and extensive validation in peer-reviewed literature make it the gold standard for any study requiring precise ERβ activation.
From its origins in Wyeth's medicinal chemistry program to its current status as a benchmark compound in hundreds of laboratories worldwide, WAY-200070 has fundamentally shaped our understanding of estrogen receptor beta biology. Whether you are investigating novel antidepressant mechanisms, exploring ERβ-based diabetes therapeutics, or studying combination approaches in breast cancer, WAY-200070 provides the pharmacological precision your research demands.
📖 Key References
1. Malamas MS, et al. "Design and synthesis of aryl diphenolic azoles as potent and selective estrogen receptor-beta ligands." J Med Chem. 2004;47(21):5021-40. PMID: 15456246.
2. Hughes ZA, et al. "WAY-200070, a selective agonist of estrogen receptor beta as a potential novel anxiolytic/antidepressant agent." Neuropharmacology. 2008;54(7):1136-42. PMID: 18423777.
3. Alonso-Magdalena P, et al. "Antidiabetic actions of an estrogen receptor β selective agonist." Diabetes. 2013;62(6):2015-25. PMID: 23349481.
4. Harris HA. "Estrogen Receptor-β: Recent Lessons from in Vivo Studies." Mol Endocrinol. 2007;21(1):1-13. PMID: 16556737.
5. "Effects of a combined treatment with tamoxifen and estrogen receptor β agonists on human breast cancer cell lines." Arch Gynecol Obstet. 2014;289(1):163-71. PMID: 23907354.
6. Clipperton Allen AE, et al. "Agonistic behavior in males and females: effects of an estrogen receptor beta agonist." Psychoneuroendocrinology. 2010;35(7):1008-22.
7. Chen F, et al. "Effects of lorazepam and WAY-200070 in larval zebrafish light/dark choice test." Neuropharmacology. 2015;95:226-33.
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