Sex and glial cells

García-Segura LM

Instituto Cajal, C.S.I.C., E-28002 Madrid, Spain

In vitro and in vivo evidence suggest that some aspects of glial cell function are different in male and female animals. Sex hormone receptors (estrogen, androgen and progesterone receptors) are expressed by glia of the CNS and PNS. However, not all glial cell types express the same repertoire of sex hormone receptors and their expression changes during development and in resting and reactive glia. Sex hormones regulate the transcription of a large variety of genes, which are relevant for the physiological and pathological responses of glial cells. In addition, sex hormones may elicit rapid signaling events in glia, via the activation of kinase signaling and by the modification of intracellular calcium levels. Furthermore, some metabolites of sex hormones such as tetrahydroprogesterone regulate glial function acting on GABAA receptors, expressed by Schwann cells and astrocytes. Sex hormones regulate the proliferation of Schwann cells and oligodendrocyte precursors and the differentiation and morphological plasticity of astrocytes. These hormones also regulate the proliferation and activation of microglia and astroglia after CNS injuries or after proinflammatory challenges. In addition, glial cells metabolize sex steroid hormones and the resulting sex steroid metabolites modulate synaptic function and impact on anxiety, cognition, sleep, ingestion, aggression, and reinforcement. Some sex steroid metabolites produced by glial cells, such as estradiol, elicit also endogenous neuroprotective mechanisms and decrease neuronal neurodegeneration under pathological conditions.

Acknowledgements: Supported by Ministerio de Ciencia e Innovación, Spain (BFU2008-02950-C03-01).