EU-ToxRisk - Peroxisome proliferation / Organic anion transporter interference

Keywords

REACH, read-across, RDT, systemic toxicity, NAM, metabolomics

Objective

The phenoxy acetic/propionic acid herbicides form a group of structurally similar herbicides are known to induce similar systemic toxicity in rat studies. The main toxicological effects observed are liver toxicity due to peroxisome proliferation as well as kidney toxicity associated with oxidative stress. Since the liver effects are mediated through activation of peroxisome proliferation, other non-herbicidal peroxisome proliferators – such as phthalates or pharmaceutical peroxisome proliferators– were tested to evaluate the NAMs in terms of general detection of peroxisome proliferation.

Testing Strategy

Data from CALUX assays, HepG2 metabolomics, and stress responses showed that the biological effects observed can be linked to the toxicological mode of action in the liver. The metabolite profile indicated changes in lipid metabolism as had been seen for peroxisome proliferators in vivo. The data for the herbicides were well in line with published in vivo findings (van Ravenzwaay et al., 2016) and demonstrated that the in vitro data might be used to substantiate a read-across based on in vitro methodologies. PBPK modelling for the compounds and test substances will be performed.