Neurodevelopmental effects of natural and synthetic ligands of estrogen and progesterone receptors in zebrafish eleutheroembryos.

•Estradiol, progesterone and norethindrone, a 19-nortestosterone synthetic progestin with estrogenic properties, affect brain expression of estrogen and progesterone nuclear receptors in zebrafish larvae.•Progesterone inhibits the proliferation in the brain of zebrafish larvae.•Estradiol inhibits the proliferation in the brain of zebrafish larvae.•Norethindrone increases the number of apoptotic cells in the brain of zebrafish larvae.•The effects induced by the three steroids on zebrafish brain development were clearly different.