# Presentation: 009841

## Overview of Ecotoxicological Assays

- <date/time>

**Overview of Ecotoxicological Assays**
**NACEPT**
**Endocrine Disruptor Methods Validation Subcommittee**
**March 2002**
**Les Touart**

## Wildlife – Human Connection

- <date/time>

## EDSTAC Recommended  Ecotoxicological Assays

- <date/time>

- Tier 1
- Fish Gonadal Recrudescence Assay
- Frog Metamorphosis Assay
- Tier 2
- Fish Life Cycle
- Avian Reproduction
- Amphibian Development and Reproduction
- Mysid Life Cycle

## Purpose of Diverse Taxa

- <date/time>

**Purpose of Diverse Taxa**
**in Screening Battery**

**To reduce the likelihood that important pathways for metabolic activation or detoxification of the test substances are overlooked**

## Fish Short-term Reproduction Assay

- <date/time>

**Fish Short-term Reproduction Assay**
**(Tier 1)**
**[a.k.a. Fish Gonadal Recrudescence Assay]**

- Unique to Screening Battery
- Adult life stage
- Oviparity
- Gametogenesis
- Spawning

## Fish Reproduction Assay(Tier 1)

- <date/time>

- Fish Reproduction Assay(Tier 1)

- _Milestone _                               			_Meeting Date_
- DRP                            			Mar 2002
- FHM comparative study  		Mar 2003
- Vitellogenin methods 		Mar 2003
- Prevalidation Report 			July 2003
- Validation Report 			  2004
- Integrated Summary			  2004

## Amphibian Metamorphosis Assay(Tier 1)

- <date/time>

- Amphibian Metamorphosis Assay(Tier 1)

- _Milestone_				_Meeting Date_
- DRP                  		June 2002
- evaluate utility & future of assay before setting milestone dates

## Why Use an Amphibian Metamorphosis Model for Thyroid Disruption?

- Amphibian metamorphosis is TH dependent event
- Transforms aquatic larval lifestage to adult tetrapod
- Characterized by:

- (adapted from Shi, et.al., 1996)

## Metamorphosis in X. laevis

- (adapted from Shi, et.al., 1996)

## Conclusions From MED Analysis of EDSTAC- Proposed Amphibian Metamorphosis Assay

- <date/time>

- EDSTAC-Proposed Frog Tail Resorption Assay is Not Ready for Use as a Screening Tool
- 1) Developmental stage 60 is relatively insensitive
- 2) Tail tissue is relatively insensitive
- 3) Changes in tail resorption rates not diagnostic
- 4) Insufficient data on known agonists/antagonists
- 5) Interaction with other endocrine systems is source of uncertainty

## German Proposal for an Amphibian Metamorphosis Assay(XEMA)

- <date/time>

- German Proposal for an Amphibian Metamorphosis Assay(XEMA)

- Uses *Xenopus laevis* at developmental stage 48
- Exposed to test substance for 28 days
- Endpoints measured
- Whole body length
- Tail length
- Staging
- Ring test underway

## Purpose of Tier 2

- <date/time>

- Determine if endocrine-active substance causes adverse effects in animals
- Identify the adverse effects
- Establish a quantitative relationship between the dose and the adverse effects

## Fish Life Cycle 

- <date/time>

**Fish Life Cycle**** **
**(Tier 2)**

- _Milestone _                                   		_Meeting Date_
- DRP			    	June 2002
- Prevalidation		    	May 2003
- Validation		            2004
- Integrated Summary             2004

## Avian 2-Generation(Tier 2)

- <date/time>

- Avian 2-Generation(Tier 2)

- _Milestone_                                             	_Meeting Date_
- DRP                                  	Dec 2002
- Dosing study 			  	Dec 2002
- Prevalidation Report             	    2004
- Validation Report                  	    2004
- Integrated Summary              	    2004

## Amphibian Development and Reproduction(Tier 2)

- <date/time>

**Amphibian Development and Reproduction****(Tier 2)**

- _Milestone_                              			 _Meeting Date_
- DRP                                  	Sept 2002
- Prevalidation Report         	    2004
- Validation Report                         2005
- Integrated Summary                   2005

## Mysid Life Cycle(Tier 2)

- <date/time>

**Mysid Life Cycle****(Tier 2)**

- _Milestone _                        		           _Meeting Date_
- DRP                                     	June 2002
- Prevalidation Report            	May 2003
- Validation Report                   	    2004
- Integrated Summary              	    2004

## OECD Activity

- <date/time>

- EDTA

- (VMGin vitro)

- VMGmammal

- VMGeco

- Test Guidelines Program

- fish

- birds

- amphibians