- Aquatic Ecotoxicology
- OECD 202: Daphnia sp., Acute Immobilisation Test
- OECD 211: Daphnia magna Reproduction Test
- OECD 235: Chironomus sp., Acute Immobilisation Test
- OECD 218/219: Sediment-Water Chironomid Toxicity Test Using Spiked Sediment/Spiked Water
- OECD 233: Sediment-Water Chironomid Life-Cycle Toxicity Test Using Spiked Water or Spiked Sediment
- OECD 225: Sediment-water Lumbriculus Toxicity Test Using Spiked Sediment
- OECD 242: Potamopyrgus antipodarum Reproduction Test
- OECD 243: Lymnea stagnalis Reproduction Test
- OECD 203: Fish, Acute Toxicity Test
- OECD 215: Fish Juvenile Growth Study
- OECD 212: Fish, Short-term Toxicity Test on Embryo and Sac-fry Stages
- OECD 231: The Amphibian Metamorphosis Assay
- OECD 236: Fish Embryo Acute Toxicity Test
- OECD 210: Fish, Early-life Stage Toxicity Test
- OECD 229 Fish Short Term Reproduction Assay and OECD 230 21-day Fish Assay
- OECD 240 Medaka Extended One Generation Reproduction Test (MEOGRT)
- OECD 241: Larval Amphibian Growth and Development Assay
- OPPTS 850.1500: Fish Life Cycle Toxicity Test
- OÈCD 234 Fish sexual development test
- Storage Stability Studies
- OPPTS 830.6302, OPPTS 830.6303,and OPPTS 830.6304: Physical State, Colour and Odor at 20 °C and at 101.3 kPa
- EU A.1: Melting temperature/range
- EU A.2: Boiling temperature
- EU A.3: Relative density (liquids and solids)
- EU A.4: Vapour pressure
- EU A.5: Surface tension
- EU A.9: Flashpoint
- EU A.10: Flammability (solids)
- EU A.12: Flammability (contact with water)
- EU A.13: Pyrophoric properties of solids and liquids
- EU A.16: Relative self-ignition temperature for solids
- EU A.17: Oxidising properties
- OECD 114: Viscosity of Liquids
- Environmental Fate
- Terrestrial Ecotoxicology
- Non-target arthropod testing with the parasitic wasp (Aphidius rhopalosiphi)
- Non-target arthropod testing with the lacewing (Chrysoperla carnea)
- Non-target arthropod testing with the ladybird beetle (Coccinella septempunctata)
- Non-target arthropod testing with the predatory bug (Orius laevigatus)
- Non-target arthropod testing with the predatory mite (Typhlodromus pyri)
- Non-target arthropod testing with the rove beetle (Aleochara bilineata)
- Non-target arthropod testing with the carabid beetle (Poecilus cupreus)
- Non-target arthropod testing with the wolf spider (Pardosa spec.)
- OECD 213/214: Honey bees, Acute Oral and Acute Contact Toxicity Test
- OECD 245: Honey Bee (Apis Mellifera L.), Chronic Oral Toxicity Test (10-Day Feeding)
- OECD 237: Honey Bee Larval Toxicity Test, Single Exposure
- OECD 239: Honey Bee Larval Toxicity Test
- EPPO 170: Honey Bee Field Study – do plant protection products effect honey bee colonies?
- Oomen et al. 1992: Honey Bee Brood Feeding Study
- OECD 75: Honey Bee Brood Test under Semi-field Conditions in Tunnels
- OECD 246/247 Acute Oral and Contact Toxicity to the Bumblebee, Bombus terrestris L.
- Solitary Bee Acute Contact Toxicity Study in the Laboratory (Osmia sp.) Solitary Bee Acute Oral Toxicity Study in the Laboratory (Osmia sp.) (protocols for ringtests with solitary bees recommended by the non-Apis working group)
- SANTE/11956/2016 rev.9 Residue trials for MRL setting in honey
- OECD 208: Terrestrial Plant Test - Seedling Emergence and Seedling Growth Test
- OECD 227: Terrestrial Plant Test - Vegetative Vigour Test
- OCSPP 850.4100: Seedling Emergence and Seedling Growth
- OCSPP 850.4150: Vegetative Vigor
- EPPO PP 1/207(2): Efficacy evaluation of plant protection products, Effects on succeeding crops
- Ecological Modelling
- Quality Assurance
- Testing of Potential Endocrine Disruptors
- Aquatic Ecotoxicology
- Who we are
- Company history
- Our Certificates
OECD 231: The Amphibian Metamorphosis Assay
The Amphibian Metamorphosis Assay (OECD 231) is designed to detect endocrine active substances acting on the thyroid system. Amphibian metamorphosis provides a well-studied, thyroid-relevant process which responds to substances active within the hypothalamic-pituitary-thyroid (HTP) axis.
This test system is of particular importance for the assessment of endocrine disrupting properties of chemicals (EFSA/ECHA 2018), as this is the case for the Larval Growth and Development Test (LAGDA, OECD 241).
The clawed frog, Xenopus laevis is routinely cultured in laboratories worldwide and is easily obtainable through commercial suppliers. Reproduction can be induced throughout the year using human chorionic gonadotropin injections and tadpoles are easily available.
Course of the test
Xenopus laevis tadpoles (stage 51) are exposed to a minimum of three different concentrations of a test chemical and a water control for 21 days in a flow through system. There are four replicates of each test treatment. Larval density at test initiation is 20 tadpoles per test tank for all treatment groups.
At the beginning of the study the tadpoles are in the developmental stage 51, which is approximately two weeks post hatch. At this stage, also known as premetamorphosis, the tadpole thyroid is not yet functional.
On study day 7, which is approximately when the thyroid gland begins functioning, five individual tadpoles are removed and the developmental stage is assessed. The remaining tadpoles are maintained in the test system for another 14 days. On day 21, when the tadpoles have fully functional thyroid glands and are capable of secreting thyroid hormones, the study is terminated and data are collected.
- Hind limb length
- Snout to vent length
- Developmental stage
- Wet weight
- Thyroid histology
- Daily observations of mortality.
Guidelines and literature
OECD Guideline for Testing of Chemicals, No. 231: The Amphibian Metamorphosis Assay.