Neurosteroids in the retina: neurodegenerative and neuroprotective agents in retinal degeneration.

Steroids may have a powerful role in neuronal degeneration. Recent research has revealed that steroids may influence the onset and progression of some retinal disorders as well as neurodegenerative diseases and, as in brain, they accumulate in the retina via a local synthesis (neurosteroids) and metabolism of blood-circulating steroid hormones. Their crucial role as neurodegenerative and neuroprotective agents has been also upheld in a retinal excitotoxic paradigm. These findings are reviewed especially from the emerging perspective that after an insult local changes in steroidogenic responses and consequent neurosteroid availability might turn out to be offensive or defensive cellular adaptations for the potentiation or prevention of neuronal death.