Steroid modulation of neurogenesis: Focus on radial glial cells in zebrafish

•The brain of adult zebrafish is a source of steroids and target of steroids.•Aromatase expression is restricted to radial glial cells in the adult zebrafish.•Radial glial cells are progenitor cells in the brain of adult zebrafish.•Estradiol negatively regulates the proliferation and the migration of newborn cells.•Aromatase expression is induced in parenchymal cells after mechanical injury.