Sex hormones and proteins involved in brain plasticity.

It is well known that peripheral sex steroid hormones cross the blood-brain barrier and control a broad spectrum of reproductive behaviors. However, their role in other essential brain functions was investigated since the 1980s, when the accumulation of pregnenolone and dehydroepiandrosterone in the brain of mammalian species was determined. Since then, numerous studies have demonstrated the participation of sex hormones in brain plasticity processes. Sex hormones through both genomic and non-genomic mechanisms of action are capable of inducing gene transcription or activating signaling cascades that result in the promotion of different physiological and pathological events of brain plasticity, such as remodeling or formation of dendritic spines, neurogenesis, synaptogenesis or myelination. In this chapter, we will present the effects of sex hormones and proteins involved in brain plasticity.