Regulated expression of estrogen receptor α and β mRNA in granule cells during development of the rat cerebellum

A semi-quantitative RT-PCR approach was used to characterize expression of the mRNA encoding estrogen receptors in developing cerebellar granule cells of the rat. Evidence is presented for expression of both ER alpha and ERP transcripts in granule cells throughout the first 15 postnatal days. While transcripts encoding both ER alpha and ERP were expressed in granule cells, the relative levels of expression varied significantly during the first two postnatal weeks of cerebellar development. The ERa mRNA was expressed at the lowest level on the first day following birth; whereas expression of ERP was highest on that day. On the fourth postnatal day the expression of ERa increased, while there was a significant decrease in BR beta expression. Between postnatal day 4 and 15, the expression of the mRNA of each receptor varied in a similar fashion; expression decreased slightly between days 4 and 10 and then increased significantly on day 15. Alternative splicing of the ERP transcripts was also investigated and was likewise found to vary during granule cell development. Initially, the mRNA encoding the pi isoform was predominant, but by day 4, the beta 2 isoform was the major isoform expressed. On postnatal days 7 and 10, there was not a significant difference between the level of pi and beta 2 expressed. By day 15, pi was again the predominant ERP isoform accounting for nearly 90% of all ER beta transcripts expressed. (C) 1999 Elsevier Science B.V. All rights reserved.