ValNAM

Funded by: BMFTR
Funding period: 2026–2029
Coordinator: German Federal Institute for Risk Assessment (BfRshort forGerman Federal Institute for Risk Assessment)

Objective
The ThyroTransVal project aims to validate an in vitro test method for identifying substances that impair the transport of thyroid hormones into target cells and across biological barriers, thereby potentially acting as endocrine disruptors. The method utilizes cells that stably express the human thyroid hormone transporter MCT8. By employing spectrophotometric detection of active T3 transport, it is possible to investigate whether test substances inhibit the uptake of thyroid hormones into cells.
As part of the project, the method is to be transferred from the developer's laboratory to several independent testing laboratories, and its robustness and reproducibility are to be assessed through a blinded ring trial. The long-term goal is for the method to be recognized as an OECD Test Guideline and applied internationally in the regulatory safety assessment of chemicals.

3R Relevance
The method enables the investigation of a key mechanism of the thyroid hormone system in vitro. It can thus contribute to replacing animal experiments previously required to identify substances with thyroid hormone-related endocrine effects. In particular, the method addresses a mechanism of action that has hitherto been insufficiently covered: the inhibition of transmembrane thyroid hormone transport.