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Relationship: 2201
Title
Antagonism, Androgen receptor leads to Altered, Transcription of genes by AR
Upstream event
Downstream event
AOPs Referencing Relationship
| AOP Name | Adjacency | Weight of Evidence | Quantitative Understanding | Point of Contact | Author Status | OECD Status |
|---|---|---|---|---|---|---|
| Androgen receptor (AR) antagonism leading to decreased fertility in females | adjacent | High | Moderate | Cataia Ives (send email) | Under development: Not open for comment. Do not cite | Under Development |
Taxonomic Applicability
Sex Applicability
| Sex | Evidence |
|---|---|
| Male | High |
| Female | High |
Life Stage Applicability
| Term | Evidence |
|---|---|
| All life stages | High |
The AR is a nuclear hormone receptor that functions primarily as a transcription factor. After binding of a ligand (androgens: DHT, testosterone) to the AR, the androgen-AR complex translocate to the nucleus and bind to specific hormone response elements on the DNA duplex to regulate gene transcription. The AR is expressed in various cells and tissues throughout the body in a spatiotemporal manner, with levels and activation changed in response to androgen signaling (Chang et al, 1995; Davey & Grossmann, 2016; Roy et al, 1999).
| ID | Experimental Design | Species | Upstream Observation | Downstream Observation | Citation (first author, year) | Notes |
|---|
| Title | First Author | Biological Plausibility |
Dose Concordance |
Temporal Concordance |
Incidence Concordance |
|---|
Biological Plausibility
Dose Concordance Evidence
Temporal Concordance Evidence
Incidence Concordance Evidence
Uncertainties and Inconsistencies
The AR gene contains CAG repeats (encoding for the amino acid glutamine), which vary between individuals and will affect transcriptional function. Broadly speaking, fewer CAG repeats tend to render the AR more sensitive to androgen activation whereas more CAG repeats tend to render the AR less sensitive, albeit the functional relevance at the tissue/organ level remains less clear (Tirabassi et al, 2015; Zitzmann, 2009). It is plausible, however, that it may lead to variable sensitivity to AR antagonism.
The quantitative relationship between AR antagonism and transcriptional activity can be measured in vitro through several available reporter assay such as AR-EcoScreen (Satoh et al, 2004) and AR-CALUX (van der Burg et al, 2010), different validated reporters assays (Körner et al, 2004) plus several more. Dose-response curve assays are performed, allowing for the calculation of potential to antagonize AR (e.g. EC50 scores, log10 Ki values). There is a large body of studies having reported on AR antagonism by numerous chemicals (Gray et al, 2020; Kleinstreuer et al, 2017; Vinggaard et al, 2008).