Developmental sex differences in estrogen receptor-beta mRNA expression in the mouse hypothalamus/preoptic region.
Estrogens play a significant role during mammalian brain development and are required for the masculinization of neuronal circuits involved in sex-specific behaviors and neuroendocrine functions. Cellular estrogen signalling is transmitted through nuclear estrogen receptors (ER) which are divided into two subforms: the ER-alpha as well as the recently cloned ER-beta have been demonstrated in the hypothalamus. In the present study, we have analyzed the sex-specific expression of ER-beta mRNA in the pre- and postnatal mouse hypothalamus/preoptic region (Hyp/POA) by semiquantitative RT-PCR. The ER-beta mRNA was detectable as early as embryonic day (E) 15 in the diencephalon of both sexes. In males, levels of mRNA expression in the Hyp/POA increased until birth and remained high throughout postnatal (P) development, whereas in females, such an increase was not observed. Significantly higher mRNA levels were detected in the male Hyp/POA from E17 until P15. Perinatal sex differences in ER-beta mRNA expression coincide with higher estrogen-forming rates in the male Hyp/POA. At present, no direct evidence is available which demonstrates that estrogen signalling through ER-beta is involved in brain development. However, data from our and other studies suggest a potential role for this signal transduction pathway for brain differentiation.
Karolczak
M
M
Abteilung Anatomie und Zellbiologie, Universität Ulm, Germany.
Beyer
C
C
D000818:Animals; D015139:Blotting, Southern; D047629:Estrogen Receptor beta; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007031:Hypothalamus / Q000737:chemistry / Q000196:embryology / Q000254:growth & development*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011301:Preoptic Area / Q000737:chemistry / Q000196:embryology / Q000254:growth & development*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis*; D011960:Receptors, Estrogen / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012737:Sex Factors
D047629:Estrogen Receptor beta; D012333:RNA, Messenger; D011960:Receptors, Estrogen