2018 Study Highlights
- Developmental EE2 exposure increases time spent on maternal self-care.
- Pups born to EE2-treated females were less likely to initiate nursing on LD14.
- Exposure to EE2 altered ERα expression in the MPOA both early and late in lactation.
- Developmental EE2 exposure decreased dopaminergic cells in the VTA on LD2.
- Effects of EDCs on maternal behavior depend on chemical and period of exposure.
Due of its structural similarity to the endogenous estrogen 17β-estradiol (E2), the synthetic estrogen 17α-ethinyl estradiol (EE2) is widely used to study the effects of estrogenic substances on sensitive organs at multiple stages of development.
Here, we investigated the effects of EE2 on maternal behavior and the maternal brain in females exposed during gestation and the perinatal period.
We assessed several components of maternal behavior including nesting behavior and pup retrieval; characterized the expression of estrogen receptor (ER)α in the medial preoptic area (MPOA), a brain region critical for the display of maternal behavior; and measured expression of tyrosine hydroxylase, a marker for dopaminergic cells, in the ventral tegmental area (VTA), a brain region important in maternal motivation.
We found that developmental exposure to EE2 induces subtle effects on several aspects of maternal behavior including time building the nest and time spent engaged in self-care. Developmental exposure to EE2 also altered ERα expression in the central MPOA during both early and late lactation and led to significantly reduced tyrosine hydroxylase immunoreactivity in the VTA.
ur results demonstrate both dose- and postpartum stage-related effects of developmental exposure to EE2 on behavior and brain that manifest later in adulthood, during the maternal period. These findings provide further evidence for effects of exposure to exogenous estrogenic compounds during the critical periods of fetal and perinatal development.