The anthropogenic contaminant tris(4-chlorophenyl)methanol (TCPMOH), believed to be a by-product of DDT manufacturing, is an emerging concern for which almost no toxicity data is available. It has been found in marine species around the world and human breast milk, demonstrating potential risk as an ecotoxicological agent and a potential reproductive and developmental toxicant. The goal of this study was to assess metabolic responses of adult and embryonic zebrafish to TCPMOH exposures, including induction of the Aryl Hydrocarbon Receptor (AHR) pathway. Wild-type zebrafish embryos and adult zebrafish were exposed to TCPMOH, and gene expression of ahr2, cyp1a, and nrf2 was measured in whole embryos or adult livers. Although there was not a significant difference in the expression of ahr2 in embryos and adults, cyp1a was significantly lower in zebrafish embryos exposed to 100 nM of TCPMOH (p=0.012). Gene expression of cyp1a was not significantly different in adult zebrafish, though the mean was elevated compared to controls. Zebrafish embryos also had a significant difference in nrf2a expression, whereas adults did not. We also found a significant difference in the spontaneous swimming behavior of adult zebrafish exposed to 50 nM of TCPMOH (p<0.001), showing a sedentary phenotype. These results suggest that the AHR and Nrf2 pathways may be sensitive to TCPMOH exposures in embryos, but that sensitivity is decreased in aging adult livers. Follow up studies are required to elucidate the mechanisms of TCPMOH-induced toxicity, and to better understand the pathological and reproductive consequences of exposures.
