Fig 1.
Illustration of a coronal section of the brain showing tissue sampling sites for the cortex (a) and hippocampus (b) [25].
CA1: CA1 region of the hippocampus; CA2: CA2 region of the hippocampus.
Fig 2.
Impairment of avoidance learning in gonadally intact low dose ethinyl estradiol (LEE)-treated female rats.
The line plot shows effects of LEE (0.02 mg/kg), HEE (2 mg/kg), and 17β-estradiol (E2; 20 mg/kg) treatment within 24 h after birth on the cumulative percentage of rats that displayed a transfer response in the passive avoidance test. Six-week-old gonadally intact animals were used in this experiment. Numerals in parentheses indicate the number of rats in each group. * P < 0.05, log-rank comparison.
Fig 3.
Impairment of avoidance learning in ovariectomized (OVX) low dose ethinyl estradiol (LEE)-treated female rats.
The line plots show the effect of LEE (0.02 mg/kg), HEE (2 mg/kg), and 17β-estradiol (E2; 20 mg/kg) treatment within 24 h after birth on the cumulative percentage of rats that displayed a transfer response in the passive avoidance test. All rats were OVX at 10 weeks of age; at 15–17 weeks, the animals were either not injected (A) or injected with EB (B) 1 day before the session. Numerals in parentheses indicate the number of rats in each group. †P < 0.1, log-rank comparison.
Fig 4.
Neonatal exposure to ethinyl estradiol (EE) decreased the expression level of estrogen receptor alpha (ERα) in the female rat cortex.
A. Representative western blot images showing the ERα expression in the cortex of EE-treated 15–18-week-old ovariectomized (OVX) rats injected with estradiol benzoate (+) or without injection (-). B. The levels of ERα in the cortex. *P < 0.05, Tukey-Kramer test; n = 6/group.
Fig 5.
Neonatal exposure to ethinyl estradiol (EE) decreases the expression level of estrogen receptor alpha (ERα) in the hippocampus of adult female rats.
A. Representative western blot images showing ERα expression in the hippocampus of EE-treated ovariectomized OVX rats injected with (+) estradiol benzoate or without injection (-) EB. B. Levels of ERα expression in the hippocampus. *P < 0.05, Tukey-Kramer test; n = 6/group.