The Amphibian Metamorphosis Assay

The Amphibian Metamorphosis Assay (AMA) serves as an in vivo screening assay intended to empirically identify substances which may interfere with the normal function of the hypothalamic-pituitary-thyroid (HPT) axis. It is an important assay because amphibian metamorphosis provides a well studied, thyroid-dependent process which responds to substances active within the HPT axis, and it is the only existing assay that detects thyroid activity in an animal undergoing morphological development. This assay is part of the OECD framework for the Testing and Assessment of Endocrine Disrupting Chemicals” under the EPA.