Aerobic
cellular metabolism requires oxygen for the efficient
production of energy and consequently produces reactive
oxygen species (ROS) including oxygen ions, free radicals
and lipid hydroperoxides. The levels of cellular ROS
are maintained within a narrow physiological range to
optimize cell performance and prevent cellular damage
by a network of antioxidant defense mechanisms. Increased
oxygen metabolism during the periparturient
period, however, augments the rate of ROS production
and the subsequent depletion of important antioxidant
defenses