Estrogen potentiates N-methyl-D-aspartate receptor subunit R2B mRNA expression during the late prepubertal period in female rats.

To study interactions between estrogen and excitatory amino acid, changes in the mRNA level of the N-methyl-D-aspartate R2B subunit (NR2B) in the hypothalamus and hippocampus were measured following estrogen treatment in prepubertal female rats. Three hours after estrogen injection, the hypothalamic and hippocampal tissues were subjected to a competitive RT-PCR assay. Estrogen significantly increased the mRNA levels of the hypothalamic NR2B in day 30 females, whereas no increase was seen in day 15 females. No such change was detected in the hippocampus. These results suggest that gene expression of hypothalamic NR2B is regulated by estrogen in peripubertal females. Differential potentiation of NR2B mRNA expression by estrogen between early and late prepubertal females suggests the existence of some neural maturational mechanism, which may be correlated with the onset of puberty.