Figure 2.

Effect of androgens on neuron and myelin regeneration. Androgens (testosterone, DHT, and DHEAS) activate ARs, which are located on the membrane of neurons and mitochondria. The activation of ARs promotes the trophism and growth of neurons and the formation of new myelin following the OPCs activation and axonal regeneration. Testosterone, after its aromatization in 17β-estradiol, activates the ERα and Erβ, improving mitochondrial function, anti-inflammatory and neurotransmission effects and protecting astrocytes. Testosterone is converted in DHT by 5α-reductase and then in androstendiol for which the metabolites 3α and 3β-diol then have a weak effect on ARs but are more active on ERβ. AR, androgen receptor; DHEAS, dehydroepiandrosterone sulfate; DHT, dihydrotestosterone; ER, estrogen receptor; OPC, oligodendrocyte precursor cell.