Organotypic culture of the developing cerebral cortex and hypothalamus: relevance to sexual differentiation.

Addition of estradiol to organotypic cultures of the rodent hypothalamus, preoptic area and cerebral cortex elicits a striking enhancement of neurite growth which is restricted to estrogen receptor-containing regions of the explants. The morphogenetic consequences of enhanced neurite growth help explain the origin of structural sexual dimorphisms in the CNS. Neurite enhancement may result from both neuronotrophic and growth-promoting actions of steroids. Steroid effects may be mediated by interactions with endogenous growth factors or their receptors. Growth-promoting effects of steroids on the developing cerebral cortex, in particular, may have relevance for sexual differentiation of cognitive functions.