- a Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- b Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA
- c Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211, USA
- d Saint Louis Zoo Institute for Conservation Medicine, St. Louis, MO 63110, USA
- e Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, MO 65212, USA
- f Department of Biology and Environmental Sciences, Westminster College, Fulton, MO 65251, USA
- g Agriculture Experimental Station-Statistics, University of Missouri, Columbia, MO 65211, USA
- h Genetics Area Program, University of Missouri, Columbia, MO 65211, USA
- i Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri, Columbia, MO 65211, USA
- Painted turtles were developmentally exposed to bisphenol A or ethinyl estradiol.
- Spatial navigational learning and memory were tested in juvenile turtles.
- Exposure to bisphenol A and ethinyl estradiol improved spatial learning and memory.
- In ovo exposure to endocrine disruptors may induce behavioral changes in turtles.
Developmental exposure of turtles and other reptiles to endocrine disrupting chemicals (EDCs), including bisphenol A (BPA) and ethinyl estradiol (EE2, estrogen present in birth control pills), can induce partial to full gonadal sex-reversal in males. No prior studies have considered whether in ovo exposure to EDCs disrupts normal brain sexual differentiation. Yet, rodent model studies indicate early exposure to these chemicals disturbs sexually selected behavioral traits, including spatial navigational learning and memory. Thus, we sought to determine whether developmental exposure of painted turtles (Chrysemys picta) to BPA and EE2 results in sex-dependent behavioral changes. At developmental stage 17, turtles incubated at 26⁰C (male-inducing temperature) were treated with 1) BPA High (100 μg /mL), 2) BPA Low (0.01 μg/mL), 3) EE2 (0.2 μg/mL), or 4) vehicle or no vehicle control groups. Five months after hatching, turtles were tested with a spatial navigational test that included four food containers, only one of which was baited with food. Each turtle was randomly assigned one container that did not change over the trial period. Each individual was tested for 14 consecutive days. Results show developmental exposure to BPA High and EE2 improved spatial navigational learning and memory, as evidenced by increased number of times spent in the correct target zone and greater likelihood of solving the maze compared to control turtles. This study is the first to show that in addition to overriding temperature sex determination (TSD) of the male gonad, these EDCs may induce sex-dependent behavioral changes in turtles.
- Behavioral testing;
- Aquatic Reptiles;
- Endocrine Disrupting Chemicals;
- Spatial Navigation;
- and Feminization
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