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Sex and Region‐Specific Regulation of Oestrogen Receptor β in the Rat Hypothalamus
Author(s) -
Orikasa C.,
Sakuma Y.
Publication year - 2004
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.2004.01254.x
Subject(s) - medicine , endocrinology , ventromedial nucleus of the hypothalamus , forebrain , sexual dimorphism , hypothalamus , sexual differentiation , amygdala , biology , receptor , nucleus , preoptic area , castration , hormone , central nervous system , neuroscience , gene , biochemistry
Sexual dimorphism in the expression of oestrogen receptor (ER)β mRNA and protein was characterized in the rostral forebrain of the rat and its dependence on the neonatal endocrine environment was revealed. We present novel data demonstrating, in gonadectomized adult rats, that the amount of oestrogen caused a significant reduction in the number of ERβ messages and protein in the ventromedial nucleus in both sexes, but no such effects were detected in the preoptic area or the amygdala. In gonadectomized females, more so than in males, the ventromedial nucleus of the adult rat contained a significantly larger number of ERβ‐positive neurones both in terms of ERβ mRNA and protein. In the juvenile rat on day 14, sex difference in ERβ expression was already observed in the ventromedial nucleus. Treatment of neonatal females with oestrogen from days 1–10 or neonatal orchidectomy of males reversed the sex difference in the ventromedial nucleus when observed on day 14, showing that the neonatal presence of oestrogen had caused irreversible masculinization of this structure. Our results suggest that sex‐specific expression of ERβ is patterned by perinatal hormone exposure: down‐regulation of ERβ caused by oestrogen in a region‐specific manner.