Volume 85, September 2016, Pages 48–55
- 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
- Received 18 March 2016, Revised 13 June 2016, Accepted 27 July 2016, Available online 29 July 2016
Highlights
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- Painted turtles were developmentally exposed to bisphenol A or ethinyl estradiol.
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- Spatial navigational learning and memory were tested in juvenile turtles.
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- Exposure to bisphenol A and ethinyl estradiol improved spatial learning and memory.
- •
- In ovo exposure to endocrine disruptors may induce behavioral changes in turtles.
Abstract
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.
Keywords
- Behavioral testing;
- Brain;
- Aquatic Reptiles;
- Endocrine Disrupting Chemicals;
- Estrogens;
- Sex;
- Spatial Navigation;
- and Feminization
© 2016 Elsevier Inc. All rights reserved.
