Journal of neuroendocrinology
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J. Neuroendocrinol. · Mar 2009
ReviewSex differences and the roles of sex steroids in apoptosis of sexually dimorphic nuclei of the preoptic area in postnatal rats.
The brain contains several sexually dimorphic nuclei that exhibit sex differences with respect to cell number. It is likely that the control of cell number by apoptotic cell death in the developing brain contributes to creating sex differences in cell number in sexually dimorphic nuclei, although the mechanisms responsible for this have not been determined completely. The milieu of sex steroids in the developing brain affects sexual differentiation in the brain. ⋯ The patterns of expression of Bcl-2 and Bax in the SDN-POA of postnatal female rats are changed to male-typical ones by treatment with oestrogen, which is normally synthesised from testicular androgen and affects the developing brain in males. In the AVPV of postnatal rats, apoptotic regulation also differs between the sexes, although Bcl-2 expression is increased and Bax expression and caspase-3 activity are decreased in females. The mechanisms of apoptosis possibly contributing to the creation of sex differences in cell number and the roles of sex steroids in apoptosis are discussed.