Nadira De Abrew, K.; Natoli, Ted; Lester, Cathy C.; Wang, Xiaohong; Shobair, Mahmoud; Subramanian, Arvind; Daston, George P.

DOI: PMID:

Abstract

Butylated hydroxytoluene (BHT) is a synthetic antioxidant widely used in many industrial sectors. BHT is a well-studied compound for which there are many favorable regulatory decisions. However, a recent opinion by the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) hypothesizes a role for BHT in endocrine disruption ANSES (2021). This opinion is based on observations in mostly rat studies where changes to thyroid physiol. are observed Enzymic induction of Cytochrome P 450-mediated thyroid hormone catabolism has been proposed as a mechanism for these observations, however, a causal relationship has not been proven. Other evidence proposed in the document includes a read across argument to butylated hydroxyanisole (BHA), another Community Rolling Action Plan (CoRAP)-listed substance with endocrine disruption concerns. We tested the hypothesis that BHT is an endocrine disruptor by using a Next Generation Risk Assessment (NGRA) method. Four different cell lines: A549, HCC1428, HepG2, and MCF7 were treated with BHT and a series of BHT analogs at 5 different concentrations, RNA was isolated from cell extracts and run on the L1000 gene array platform. A toxicogenomics-based assessment was performed by comparing BHT′s unique genomic signature to a large external database containing signatures of other compounds (including many known endocrine disruptors) to identify if any endocrine disruption-related modes of action (MoAs) are prevalent among BHT and other compounds with similar genomic signatures. In addition, we performed a toxicogenomics-based structure activity relationship (SAR) assessment of BHT and a series of structurally similar analogs to understand if endocrine disruption is a relevant MoA for chems. that are considered suitable analogs to BHT using the P&G read across framework (Wu et al., 2010). Neither BHT nor any of its analogs connected to compounds that had endocrine activity for estrogens, androgens, thyroid, or steroidogenesis.

Keywords

estrogen, androgen, or thyroid hormone receptors, or proteins integral to steroidogenesis (EATS) ; connectivity mapping ; toxicogenomics ; read across ; New Approach Methodologies (NAM) ; Next Generation Risk Assessment (NGRA)

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