Estrogen receptor mRNA alterations in the developing rat hippocampus

Joan A. O'Keefe, Yanbing Li, Loyd H. Burgess, Robert J. Handa

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


We previously reported transiently elevated ER protein levels in the postnatal rat hippocampus suggesting that this brain region may be sensitive to estrogenic trophic and organizational influences during a 'critical period' of sexual differentiation. In order to examine whether alterations in ER gene expression underlie the ontogenetic pattern of the hippocampal ER, we examined ER mRNA levels over the early postnatal period and in adult rats. This was accomplished by both a highly quantitative RNase protection assay and in situ hybridization histochemistry. Hippocampal ER mRNA levels increased significantly (P < 0.005) between birth and postnatal day (PND) 4 when peak concentrations were found and then declined by PND-10. Adult male hippocampal ER mRNA values were similar to those found in newborn and PND-10 animals but were significantly less (P < 0.05) than those observed on PND-4. Results from the in situ hybridization experiments correlated well with those from the RNase protection analysis. High levels of ER mRNA were present in the CA3 pyramidal layer with somewhat lower labeling intensities present in CA1 and the dentate gyrus of the PND-4 animal. In contrast, adult male animals demonstrated little hybridization throughout the hippocampus. Thus, the temporal pattern in ER mRNA levels in the hippocampus found in the present study correlates well with our previous developmental profile of the ER protein. These findings suggest that the ontogeny of ER in the hippocampus is regulated by alterations in ER gene expression in specific neuronal populations.

Original languageEnglish (US)
Pages (from-to)115-124
Number of pages10
JournalMolecular Brain Research
Issue number1
StatePublished - May 1995


  • Gonadal steroid
  • In situ hybridization
  • RNase protection
  • Sexual differentiation

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience


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