EDCs Reorganize Brain-Behavior Phenotypic Relationships in Rats

All species, including humans, are exposed to endocrine-disrupting chemicals (EDCs). Previous experiments have shown behavioral deficits caused by EDCs that have implications for social competence and sexual selection. The neuromolecular mechanisms for these behavioral changes induced by EDCs have not been thoroughly explored. Here, we tested the hypothesis that EDCs administered to rats during a critical period of embryonic brain development would lead to the disruption of normal social preference behavior, and that this involves a network of underlying gene pathways in brain regions that regulate these behaviors. Rats were exposed prenatally to human-relevant concentrations of EDCs (polychlorinated biphenyls [PCBs], vinclozolin [VIN]), or vehicle. In adulthood, a sociosexual preference test was administered. We profiled gene expression of in preoptic area, medial amygdala, and ventromedial nucleus. Prenatal PCBs impaired sociosexual preference in both sexes, and VIN disrupted this behavior in males. Each brain region had unique sets of genes altered in a sex- and EDC-specific manner. The effects of EDCs on individual traits were typically small, but robust; EDC exposure changed the relationships between gene expression and behavior, a pattern we refer to as dis-integration and reconstitution. These findings underscore the effects that developmental exposure to EDCs can have on adult social behavior, highlight sex-specific and individual variation in responses, and provide a foundation for further work on the disruption of genes and behavior after prenatal exposure to EDCs.