Radiation Hormesis: The Link to Nanomolar Hydrogen Peroxide

Hydrogen peroxide (H 2 O 2 ) is a stable product of water radiolysis, occurring at nanomolar concentration upon low-dose ionizing radiation (LDIR) (<100 mGy). In view of the recent recognition of H 2 O 2 as a central redox signaling molecule that, likewise, is maintained in the nanomolar range in cells, we propose a role for H 2 O 2 in radiation hormesis. LDIR is capable of utilizing known molecular redox master switches such as Nrf2/Keap1 or NF-κB/IκB to effect adaptive resistance. This leads to the hypothesis that, as a normal component of the exposome, LDIR mediates hormetic effects by H 2 O 2 signaling. Antioxid. Redox Signal. 27, 596–598.