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Relationship: 3449

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Decrease, intratesticular testosterone leads to AGD, decreased

Upstream event

The causing Key Event (KE) in a Key Event Relationship (KER). More help

Decrease, intratesticular testosterone

Downstream event

The responding Key Event (KE) in a Key Event Relationship (KER). More help

AGD, decreased

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name	Adjacency	Weight of Evidence	Quantitative Understanding	Point of Contact	Author Status	OECD Status
Decreased testosterone synthesis leading to short anogenital distance (AGD) in male (mammalian) offspring	non-adjacent	Moderate	Moderate	Terje Svingen (send email)	Under development: Not open for comment. Do not cite	Under Review

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER. More help

Term	Scientific Term	Evidence	Link
mammals	mammals		NCBI
rat	Rattus norvegicus	High	NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help

Sex	Evidence
Male	High

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER. More help

Term	Evidence
Foetal	High

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

This non-adjacent KER describes a fetal decrease in testicular testosterone leading to short AGD in male offspring. In this KER, intratesticular testosterone levels can both be measured in whole testes extracts or by measuring ex vivo testosterone production from exposed testes.

In male mammals, the testes first differentiate in early fetal life and start synthesizing testosterone through the steroidogenesis pathway. Although the adrenal glands may also produce testosterone, the testes are the main site of testosterone production (Naamneh Elzenaty et al., 2022). Testosterone is secreted to initiate male reproductive differentiation in the peripheral tissues, either directly acting on the androgen receptor (AR) or through conversion to the more potent androgen dihydrotestosterone (DHT). The androgen hormones initiate masculinization, including elongation of the perineum, which is suggested to involve the perineal muscle complex levator ani bulbocavernous (LABC). LABC expresses AR and increases in size by androgen programming (Schwartz CL et al., 2019). The perineum is programmed in the masculinization programming window (GD 16-20 in rats, GW 8-14 in humans), when testicular testosterone production is high (Sharpe RM, 2020; Welsh M et al., 2014). Thus, a decrease in testicular testosterone levels in this window may limit the AR signaling in the LABC, leading to less elongation of the perineum and a short AGD.

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings. Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Collection Strategy

A systematic approach was used to collect evidence based on the methodology described in (Holmer et al., 2024). The evidence collection for this KER was done concurrently with the evidence collection for KER 3349 ‘decreased circulating testosterone leads to decreased AGD’, for which the same search string was used. The extracted data was then at the end divided into each KER. See figure 1: 4am0temoj0_Figure_1.pdf

Search strategy

Search strings were synthesized for PubMed and Web of Science Core Collection based on the review question ‘Does decreased testosterone during fetal development lead to decreased anogenital distance in male mammals?’

Search string in PubMed: "testosterone*" AND ("anogenital distance*” OR “AGD”)

Search string in Web of Science Core Collection: "testosterone*" AND ("anogenital distance*” OR "AGD")

Title & abstract screening:

Retrieved articles were screened in the online tool RAYYAN https://www.rayyan.ai/

After removal of duplicates, the titles and abstracts of the remaining 649 articles were screened according to pre-defined inclusion and exclusion criteria:

Inclusion criteria:

In vivo studies in male mammals where fetal testosterone is reduced and AGD is measured¹
Reviews on AGD
Epidemiologic studies with measurement of testosterone levels and AGD as an outcome
In vitro, ex vivo, and in vivo mechanistic studies on AGD

Exclusion criteria:

Papers not in English
Abstracts and other non-full text publications

¹In cases where this criterion could not be determined by reading the abstract, the full texts were checked in the reference manager Zotero to determine if the testosterone levels were reduced, and when the measurements were made.

Full text review, data extraction and reliability evaluation of animal studies:

For the in vivo studies, the full-text papers were reviewed using the same exclusion criteria as in the title & abstract screening, and data were extracted from the included papers into an Excel template. In parallel, methodological reliability was assessed using the online tool Science in Risk Assessment and Policy (SciRAP; http://www.scirap.org, see appendix 1: Microsoft Word - KER 3449_Appendix 1.docx). Based on the SciRAP evaluations, animal studies were assigned a reliability category using the principles outlined in table 1. Studies were divided into different datasets, if multiple different chemicals, different exposure windows or different timepoints of measurement of AGD were included.

Moreover, as this KER was made in parallel with several other KER for other male reproductive endpoints (nipple retention and hypospadias), eight studies retrieved in the searches for these KERs and measuring AGD, but not detected in the search for this KER were also added, data extracted and evaluated for reliability.

The collected data was then filtered to only include data sets measuring intratesticular testosterone, either in whole testes or production during ex vivo testes culture.

Overall confidence in the collected data was assessed according to the principles outlined in table 2. Only studies in reliability categories 1 (reliable without restriction) and 2 (reliable with restriction) were used for the assessment of overall confidence in the data. This resulted in 24 in vivo data set for empirical evidence.

Table 1 Principles for translation SciRAP evaluations into reliability categories.

Reliability Category	Principles for Categorization
1.Reliable without restriction	SciRAP methodological quality Score > 80 and all key criteria^a are “Fulfilled” and there are no deficiencies in the non-key criteria that might affect study reliability.
2. Reliable with restriction	SciRAP methodological quality Score > 65 and one or several of the key criteria are “Partially Fulfilled” or there are minor deficiencies in the non-key criteria that might affect study reliability.
3. Not reliable	SciRAP methodological quality Score < 65 or one or several of the key criteria are “Not Fulfilled” or there are major deficiencies in the non-key criteria that affect study reliability.
4. Not assignable	Two or more of the key criteria are “Not Determined”

^aKey criteria were criteria judged as specifically critical for reliability of the data for this KER and were determined a priori. The key criteria for this data collection are outlined in appendix 1.

Table 2 Principles for evaluation of overall confidence in data

Level of confidence	Principles for Categorization^a
Strong	Effects were observed in one or more studies judged as reliable without restriction or reliable with restriction; there are no conflicting results from studies judged as reliable with or without restriction. OR Effects were observed in one or more studies judged as reliable without restriction or reliable with restriction but conflicting results, i.e. no or opposite effects were observed in other studies judged as reliable with or without restriction. However, conflicts of results can be explained by differences in study design, for example different exposure periods, doses or animal species or cell models.
Moderate	Effects were observed in one or more studies judged as reliable without restriction or reliable with restriction but conflicting results, i.e., no or opposite effects were observed in other studies judged as reliable with or without restriction. Conflicts of results cannot be explained by differences in study design, for example different exposure periods, doses or animal species or cell models. Effects were observed in at least half of the studies.
Weak	Effects were observed in one or more studies judged as reliable without restriction or reliable with restriction but conflicting results, i.e., no or opposite effects were observed in other studies judged as reliable with or without restriction. Conflicts of results cannot be explained by differences in study design, for example different exposure periods, doses or animal species or cell models. Effects were observed in fewer than half of the studies. OR Effects were only observed in one or more studies judged as not reliable or not assignable.
No effect	No effects were observed in any of the studies reviewed.

^a Conflicting results from studies judged as not reliable do not impact categorization.

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

Biological Plausibility

Addresses the biological rationale for a connection between KEupstream and KEdownstream. This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured. More help

The biological plausibility for this KER is judged to be high given the canonical biological knowledge on normal reproductive development.

Sexual differentiation in males, including elongation (masculinization) of the perineum, is initiated and programmed in fetal life. Around GW 8 in humans and GD16 in rats, the testes have formed and start synthesizing testosterone through the steroidogenesis pathway. Testicular testosterone is secreted to either act directly on the AR or be converted to the more potent androgen hormone (DHT). AR activation in the perineum of males programs it to elongate, resulting in a longer AGD in males than in females (~twice the length in rats and humans) (Murashima et al., 2015b; Trost & Mulhall, 2016; Welsh M et al., 2014)

The programming of the reproductive tissues, including masculinization of the perineum happens in the masculinization programming window (GD 16-20 in rats, GW 8-14 in humans) (Welsh M et al., 2014).

Given the dependency of testosterone for elongation of the perineum, either through direct AR activation or conversion to DHT, it is highly plausible that a decrease in testicular levels of testosterone will lead to a shorter AGD in males.

Empirical Evidence

Provides specific (citable) evidence that supports the idea of a change in the upstream KE (KEupstream) leading to, or being associated with, a subsequent change in the downstream KE (KEdownstream), assuming the perturbation of KEupstream is sufficient. More help

The overall empirical evidence for this KER is judged as strong.

A total of 19 data sets were collected as evidence for this KER (table 3 and appendix 2: Microsoft Word - KER 3449_appendix 2.docx). Of these, 14 studies, all in rats, show that exposure to a stressor that decreased fetal intratesticular testosterone also caused a short AGD.

Table 3 Empirical evidence for KER 3449 LOAEL: Lowest observed adverse effect level; NOAEL: No observed adverse effect level; ITT: Intratesticular testosterone measured in whole testes; Ex vivo: Testosterone production measured by incubation of testes and collection of media. See appendix 2 for specifications.

Species	Stressors(s)	Effect on upstream event *(intratesticular or ex vivo* testosterone)**	Effect on downstream event (AGD)¹	Reference
Rat	α-cypermethrin	LOAEL 5 mg/kg	No effect NOAEL 10 mg/kg	(Saillenfait AM et al., 2017)
Rat	Butyl benzyl phthalate	LOAEL 500 mg/kg	LOAEL 500 mg/kg at PND2, but not adult	(Hotchkiss AK et al., 2004)
Rat	Butyl benzyl phthalate + Linuron	LOAEL 500 + 75 mg/kg	LOAEL 500 + 75 mg/kg	(Hotchkiss AK et al., 2004)
Rat	Dibutyl phthalate	LOAEL 500 mg/kg	LOAEL 500 mg/kg	(Lourenço AC et al., 2014)
Rat	Dibutyl phthalate	LOAEL 500 mg/kg	LOAEL 100 mg/kg for AGDi, LOAEL 500 mg/kg for AGD	(Martino-Andrade AJ et al., 2009)
Rat	Dibutyl phthalate	LOAEL 500 mg/kg	LOAEL 500 mg/kg	(Pike et al., 2014)
Rat	Dibutyl phthalate	LOAEL 100 mg/kg	LOAEL 500 mg/kg	(Struve MF et al., 2009)
Rat	Dibutyl pthalate	LOAEL 750 mg/kg	LOAEL 750 mg/kg	(van den Driesche et al., 2020)
Rat	Dibutyl phthalate + Diethylhexyl pthalate	LOAEL 100 + 150 mg/kg	No effect NOAEL 100 + 150 mg/kg	(Martino-Andrade AJ et al., 2009)
Rat	Diethylhexyl phthalate	LOAEL 750 mg/kg	LOAEL 750 mg/kg	(Borch J et al., 2004)
Rat	Diethylhexyl phthalate + Diethylhydroxylamine	LOAEL 750 + 400 mg/kg	LOAEL 750 + 400 mg/kg	(Borch J et al., 2004)
Rat	Diisonyl phthalate	Decreased ITT at 600 mg/kg but not at 750 and 900 mg/kg No effect ex vivo	LOAEL 900 mg/kg	(Boberg J et al., 2011)
Rat	Diisobutyl phthalate	LOAEL 250 mg/kg	LOAEL 250 mg/kg for AGD index, no effect on AGD	(Saillenfait AM et al., 2017)
Rat	Diisonyl phthalate	LOAEL 250 mg/kg at GD19 No effect at GD20 NOAEL 750 mg/kg	No effect NOAEL 750 mg/kg	(Clewell et al., 2013)
Rat	Ketoconazole	LOAEL 50 mg/kg No effect ex vivo	LOAEL 50 mg/kg	(Taxvig et al 2008)
Rat	Linuron	LOAEL 75 mg/kg	LOAEL 75 mg/kg	(Hotchkiss AK et al., 2004)
Rat	Prochloraz	LOAEL 50 mg/kg	LOAEL 50 mg/kg	(Laier P et al., 2006)
Rat	Prochloraz	ITT LOAEL 30 mg/kg No effect ex vivo	No effect NOAEL 30 mg/kg	(Vinggaard AM et al., 2005)
Rat	Mixture (prochloraz, deltamethrin, methiocarb, simazine, tribenuron)	LOAEL 20 mg/kg	No effect NOAEL 20 mg/kg	(Vinggaard AM et al., 2005)
Rat	Mixture (BBP, DBP, DCHP, DEHP, DHEP, DHP, DIBP, DIHEP, DPEP, LIN, DDE, PCZ, PCD, PFQ, VIN)	LOAEL 6.25% of full dose	LOAEL 12.5% of full dose for AGD index, LOAEL 25% of full dose for AGD	(Conley JM et al., 2021)

¹NOAEL and LOAEL were, when available, based on AGDi data. For some datasets, only AGD or AGD/bw were available, see appendix 1 for details on each dataset.

Dose concordance

Overall, the empirical evidence supports dose concordance, although with some inconsistencies.

Five different studies show that in utero dibutyl phthalate exposure reduces intratesticular testosterone and AGD. Three of these studies report the same LOAEL for reduced intratesticular testosterone and short AGD, respectively (Lourenço AC et al., 2014; Pike et al., 2014; van den Driesche S et al., 2020). In one study, the LOAEL for reduced intratesticular testosterone was 500 mg/kg/day, while the LOAEL for short AGD was 100 mg/kg/day, thus not showing dose concordance (Martino-Andrade AJ et al., 2009). In contrast, another study reports 100 mg/kg/day as LOAEL for reduced intratesticular testosterone and 500 mg/kg/day as LOAEL for short AGD (Struve MF et al., 2009).

Two studies used prochloraz as the stressor. One study showed a reduction in testosterone in the testes at a dose of 30 mg/kg bw/day, but no effect on ex vivo testosterone production or on AGD (Vinggaard AM et al., 2005). The other study tested 50 and 150 mg/kg bw/day prochloraz and found an effect on both intratesticular testosterone (both in testes and ex vivo) and on AGD in the male offspring (Laier P et al., 2006).

Of the remaining empirical evidence, most studies report the same LOAEL for reduced intratesticular testosterone and short AGD, but for many of these cases only one chemical dose was tested.

Temporal concordance

Overall, the empirical evidence supports temporal concordance.

In several of the studies, AGD was measured at a later timepoint, often postnatally, than intratesticular testosterone. For example, exposure of rats from GD14-18 to a mixture of butyl benzyl phthalate (500 mg/kg bw/day) and linuron (75 mg/kg bw/day) reduced intratesticular testosterone levels at GD18 and caused short AGD in the males, which could be measured at both PND2 and in adult rats (Hotchkiss AK et al., 2004). Exposure to only 500 mg/kg bw/day butyl benzyl phthalate (500 mg/kg bw/day) from GD14-18 also reduced intratesticular testosterone levels at GD18 and caused short AGD at PND2, but in adult males, the effect on AGD was no longer significant. Exposure to linuron alone (75 mg/kg bw/day) in the same study caused both reduced intratesticular testosterone and short AGD at PND2 and in adult males (Hotchkiss AK et al., 2004). This may indicate that the fetal effect on AGD is best detected in early postnatal life.

In ten studies, AGD was measured prenatally, either at the same time or a day after the intratesticular testosterone measurements. Three of these studies did not find an effect on short AGD when intratesticular testosterone was measured. For example, exposure to α-cypermethrin from GD13-19 in four different doses reduced ex vivo testosterone production in testes at GD19 with LOAEL of 5 mg/kg bw/day, but AGD at GD19 was not affected at this dose or at 10 mg/kg bw/day (Saillenfait AM et al., 2017). In the same study, however, exposure to diisobutyl phthalate (250 mg/kg bw/day) caused both a reduction in ex vivo testosterone and AGD on GD19, although the effect on AGD was small (Saillenfait AM et al., 2017).

Incidence concordance

Because the data mainly includes chemicals at different doses and exposure windows, and all data are continuous, they do not firmly establish incidence concordance of this KER. However, a few studies have used the same stressors at the same doses and provide some information on incidence concordance.

Five studies used the stressor dibutyl phthalate, three of them testing the same two doses, 100 and 500 mg/kg bw/day, although with slightly different exposure windows and timepoints of AGD measurement. Of these three studies, two found the LOAEL for reduced intratesticular testosterone to be 500 mg/kg bw/day (Martino-Andrade AJ et al., 2009; Pike et al., 2014), while one detected a reduction in testosterone at 100 mg/kg bw/day (Struve MF et al., 2009). Regarding AGD, one study reported 100 mg/kg bw/day as the LOAEL, i.e. lower than the LOAEL for intratesticular testosterone (Martino-Andrade AJ et al., 2009), while the others reported 500 mg/kg bw/day as the LOAEL (Pike et al., 2014; Struve MF et al., 2009). Thus, these studies are conflicting regarding incidence concordance.

There are also three studies using diisobutyl phthalate as stressor. These vary more in terms of doses, but overall they see subtle and more uncertain effects on both intratesticular testosterone and AGD with LOAELs ranging from 50 to 250 mg/kg bw/day for both measurements (Clewell et al., 2013; Saillenfait AM et al., 2017; Taxvig C et al., 2008).

Uncertainties and Inconsistencies

Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

One uncertainty in empirical data for this KER is the studies where intratesticular testosterone was measured in an ex vivo testes incubation experiment. With this method, there is an uncertainty of the direct relationship between the ex vivo secretion, as testosterone was measured in media, and the exact intratesticular testosterone levels. However, in most of the studies using this ex vivo method, intratesticular testosterone was also measured in testes homogenates (see appendix 2) with similar outcomes using both methods, suggesting that ex vivo testosterone production after incubation can be used as a proxy for intratesticular testosterone , exemplified by very identical measurements in (Borch J et al., 2004). In the three studies, only measure testosterone production ex vivo (Conley JM et al., 2021; Saillenfait AM et al., 2017), the uncertainty in this measurements should be kept in mind.

Five data sets did not measure any effect of the stressors on AGD. In two cases, this could be due to the AGD measurements either being measured too early to measure detectable differences between groups (Saillenfait AM et al., 2017) or having too high variance to gain statistical significance (Martino-Andrade AJ et al., 2009). In the three other cases, the lack of effect on AGD was likely due to only testing one dose of the stressor (Vinggaard AM et al., 2005) (dose concordance) or the doses tested were too low (Clewell et al., 2013).

Another uncertainty is the inconsistencies between studies for the stressor dibutyl phthalate. One study report the LOAEL for reduced intratesticular testosterone as 100 mg/kg/day (Struve MF et al., 2009), while others report 500 mg/kg/day (one of these only use on dose) (Lourenço AC et al., 2014; Martino-Andrade AJ et al., 2009; Pike et al., 2014). Similarly, the LOAEL for short AGD is inconsistent, with 500 mg/kg/day being reported in three studies (Lourenço AC et al., 2014; Pike et al., 2014; Struve MF et al., 2009), and 100 mg/kg/day being reported in one (Martino-Andrade AJ et al., 2009).

Finally, one study containing uncertainties is a study on diisonyl phthalate (Boberg et al., 2011). In this study, exposure from GD7-21 to 600 mg/kg/day, but not 750 or 900 mg/kg bw/day reduced intratesticular testosterone, while 900 mg/kg/day caused short AGD. However, both 750 and 900 mg/kg bw/dag diisonyl phthalate tended to decrease intratesticular testosterone levels, and the lack of statistical significance may therefore be explained by a low sample size for these measurements (n=3-4 litters, 1-2 testes per litter).

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references. More help

There are no known modulating factors for this KER.

Quantitative Understanding of the Linkage

Captures information that helps to define how much change in the upstream KE, and/or for how long, is needed to elicit a detectable and defined change in the downstream KE. More help

Response-response Relationship

Provides sources of data that define the response-response relationships between the KEs. More help

There are no direct models for reductions in intratesticular testosterone levels and AGD. A model for phthalates has been developed, aiming to predict reductions in AGD based on the reduction in ex vivo testosterone production. In this model, a 5-parameter logistic regression model, around 60% testosterone reduction can cause a decreased AGD, with a steep declining curve as testosterone production decreases. It must be emphasized that this model, however, was only developed for the phthalates and does therefore not directly evidence the same relationship for other stressors reducing testosterone levels (Earl Gray L Jr et al., 2024).

Time-scale

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help

The exact timescale of this KER depends on the species, but it may take days or weeks for growth changes in the perineum to be measurable. In humans, testosterone production in the testes begin around GW8, and sexual dimorphism of the perineum between males and females can be measured by GW11-13, reaching the full 2:1 male:female ratio in length at GW17-20 (Thankamony A et al., 2016)

Known Feedforward/Feedback loops influencing this KER

Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

There are no known feedback/feedforward loops for this KER

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

Taxonomic applicability

Testosterone, synthesized in the testis, is essential for growth (masculinization) of the male perineum in all mammals. It is therefore biologically plausible that this KER is applicable to all mammals (Murashima et al., 2015a). The empirical evidence in this KER strongly supports the applicability to rats in particular. Given the knowledge of normal reproductive development, the KER is also considered applicable to humans.

Sex applicability

Testes are the primary male sex organs; hence, this KER is only applicable to males. The empirical evidence in this KER supports the applicability in males.

Life stage applicability

The perineum is programmed by androgens during the masculinization programming window, a fetal period during which the testes produce high levels of testosterone. The masculinization programming window is ~gestational day (GD) 16-20 in rats and suggested to be gestational weeks (GW) 8-14 in humans (Sharpe RM, 2020; Welsh M et al., 2014). Once programmed in fetal life, the AGD is believed to be relatively stable, but the perineum can in some cases be responsive to postnatal changes in androgen levels (Schwartz CL et al., 2019; Sharpe RM, 2020; Thankamony A et al., 2016). The empirical evidence in this KER supports the fetal life stage applicability.

References

List of the literature that was cited for this KER description. More help

Boberg, J., Christiansen, S., Axelstad, M., Kledal, T. S., Vinggaard, A. M., Dalgaard, M., Nellemann, C., & Hass, U. (2011). Reproductive and behavioral effects of diisononyl phthalate (DINP) in perinatally exposed rats. REPRODUCTIVE TOXICOLOGY, 31(2), 200–209. https://doi.org/10.1016/j.reprotox.2010.11.001

Borch J, Ladefoged O, Hass U, & Vinggaard AM. (2004). Steroidogenesis in fetal male rats is reduced by DEHP and DINP, but endocrine effects of DEHP are not modulated by DEHA in fetal, prepubertal and adult male rats. Reproductive Toxicology (Elmsford, N.Y.), 18(1), 53–61. https://doi.org/10.1016/j.reprotox.2003.10.011

Clewell, R. A., Sochaski, M., Edwards, K., Creasy, D. M., Willson, G., & Andersen, M. E. (2013). Disposition of diiosononyl phthalate and its effects on sexual development of the male fetus following repeated dosing in pregnant rats. REPRODUCTIVE TOXICOLOGY, 35, 56–69. https://doi.org/10.1016/j.reprotox.2012.07.001

Conley JM, Lambright CS, Evans N, Cardon M, Medlock-Kakaley E, Wilson VS, & Gray LE Jr. (2021). A mixture of 15 phthalates and pesticides below individual chemical no observed adverse effect levels (NOAELs) produces reproductive tract malformations in the male rat. Environment International, 156, 106615. https://doi.org/10.1016/j.envint.2021.106615

Earl Gray L Jr, Lambright CS, Evans N, Ford J, & Conley JM. (2024). Using targeted fetal rat testis genomic and endocrine alterations to predict the effects of a phthalate mixture on the male reproductive tract. Current Research in Toxicology, 7, 100180. https://doi.org/10.1016/j.crtox.2024.100180

Holmer, M. L., Zilliacus, J., Draskau, M. K., Hlisníková, H., Beronius, A., & Svingen, T. (2024). Methodology for developing data-rich Key Event Relationships for Adverse Outcome Pathways exemplified by linking decreased androgen receptor activity with decreased anogenital distance. Reproductive Toxicology, 128, 108662. https://doi.org/10.1016/j.reprotox.2024.108662

Hotchkiss AK, Parks-Saldutti LG, Ostby JS, Lambright C, Furr J, Vandenbergh JG, & Gray LE Jr. (2004). A mixture of the “antiandrogens” linuron and butyl benzyl phthalate alters sexual differentiation of the male rat in a cumulative fashion. Biology of Reproduction, 71(6), 1852–1861. https://doi.org/10.1095/biolreprod.104.031674

Laier P, Metzdorff SB, Borch J, Hagen ML, Hass U, Christiansen S, Axelstad M, Kledal T, Dalgaard M, McKinnell C, Brokken LJ, & Vinggaard AM. (2006). Mechanisms of action underlying the antiandrogenic effects of the fungicide prochloraz. Toxicology and Applied Pharmacology, 213(2), 160–171. https://doi.org/10.1016/j.taap.2005.10.013

Lourenço AC, Gomes C, Boareto AC, Mueller RP, Nihi F, Andrade LF, Trindade ES, Coelho I, Naliwaiko K, Morais RN, & Martino-Andrade AJ. (2014). Influence of oily vehicles on fetal testis and lipid profile of rats exposed to di-butyl phthalate. Human & Experimental Toxicology, 33(1), 54–63. https://doi.org/10.1177/0960327112474847

Martino-Andrade AJ, Morais RN, Botelho GG, Muller G, Grande SW, Carpentieri GB, Leão GM, & Dalsenter PR. (2009). Coadministration of active phthalates results in disruption of foetal testicular function in rats. International Journal of Andrology, 32(6), 704–712. https://doi.org/10.1111/j.1365-2605.2008.00939.x

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