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Sex differences in brain developing in the presence or absence of gonads
Author(s) -
Büdefeld Tomaz,
Grgurevic Neza,
Tobet Stuart A.,
Majdic Gregor
Publication year - 2008
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20638
Subject(s) - biology , endocrinology , medicine , gonad , sexual differentiation , sexual dimorphism , hypothalamus , calbindin , hormone , genetics , gene , immunohistochemistry , immunology
Abstract Brain sexual differentiation results from the interaction of genetic and hormonal influences. This study used a unique agonadal mouse model to determine relative contributions of genetic and gonadal hormone influences in the differentiation of selected brain regions. SF‐1 knockout (SF‐1 KO) mice are born without gonads and adrenal glands and are not exposed to endogenous sex steroids during fetal/neonatal development. Consequently, male and female SF‐1 KO mice are born with female external genitalia and if left on their own, die shortly after birth due to adrenal insufficiency. In this study, SF‐1 KO mice were rescued by neonatal adrenal transplantation to examine their brain morphology in adult life. To determine potential brain loci that might mediate functional sex differences, we examined the area and distribution of immunoreactive calbindin and neuronal nitric oxide synthase in the preoptic area (POA) and ventromedial nucleus of the hypothalamus, two areas previously reported to be sexually dimorphic in the mammalian brain. A sex difference in the positioning of cells containing immunoreactive calbindin in a group within the POA was clearly gonad dependent based on the elimination of the sex difference in SF‐1 KO mice. Several other differences in the area of ventromedial hypothalamus and in POA were maintained in male and female SF‐1 KO mice, suggesting gonad‐independent genetic influences on sexually dimorphic brain development. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008