In the CA1 region, estrogen treatment increases dendritic spines and synapse density on pyramidal cells.
Estrogens also mediate aspects of sexual differentiation of the hippocampus.
No significant sex difference in distribution and intensity of the ER a mRNA positive cells were detected. The hippocampal distribution of ER a mRNA expression at PND14 remained the same on PND21 and 35 and in adulthood. As reported for adults, ER a mRNA signals appear to be in interneurons of the hippocampus but neither in the pyramidal cells nor in the dentate granular cells based on their size and location.