Developmental exposure to bisphenol A (BPA) alters sexual differentiation in painted turtles (Chrysemys picta)

General and Comparative Endocrinology
By: , and 

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Abstract

Environmental chemicals can disrupt endocrine signaling and adversely impact sexual differentiation in wildlife. Bisphenol A (BPA) is an estrogenic chemical commonly found in a variety of habitats. In this study, we used painted turtles (Chrysemys picta), which have temperature-dependent sex determination (TSD), as an animal model for ontogenetic endocrine disruption by BPA. We hypothesized that BPA would override TSD and disrupt sexual development. We incubated farm-raised turtle eggs at the male-producing temperature (26 °C), randomly assigned individuals to treatment groups: control, vehicle control, 17β-estradiol (E2, 20 ng/g-egg) or 0.01, 1.0, 100 μg BPA/g-egg and harvested tissues at hatch. Typical female gonads were present in 89% of the E2-treated “males”, but in none of the control males (n = 35). Gonads of BPA-exposed turtles had varying amounts of ovarian-like cortical (OLC) tissue and disorganized testicular tubules in the medulla. Although the percentage of males with OLCs increased with BPA dose (BPA-low = 30%, BPA-medium = 33%, BPA-high = 39%), this difference was not significant (p = 0.85). In all three BPA treatments, SOX9 patterns revealed disorganized medullary testicular tubules and β-catenin expression in a thickened cortex. Liver vitellogenin, a female-specific liver protein commonly used as an exposure biomarker, was not induced by any of the treatments. Notably, these results suggest that developmental exposure to BPA disrupts sexual differentiation in painted turtles. Further examination is necessary to determine the underlying mechanisms of sex reversal in reptiles and how these translate to EDC exposure in wild populations.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Developmental exposure to bisphenol A (BPA) alters sexual differentiation in painted turtles (Chrysemys picta)
Series title General and Comparative Endocrinology
DOI 10.1016/j.ygcen.2015.04.003
Volume 216
Year Published 2015
Language English
Publisher Elsevier
Contributing office(s) Columbia Environmental Research Center, Contaminant Biology Program
Description 9 p.
First page 77
Last page 85
Online Only (Y/N) N
Additional Online Files (Y/N) N