Properties of electrochemically active components in mammalian vitreous humor

Antioxidants are considered to have important roles in protecting the eye against radiation, oxygen toxicity and other threats. Several water-soluble electrochemically-active compounds that might function as antioxidants in vitreous humor of rabbit, rat and bovine eyes were identified and quantitated. In that the rat is a nocturnal animal species and the other two are diurnal, the results allow a tentative evaluation on the comparative physiology of light-dark behavior patterns that influence this ocular fluid. All analyses were performed by HPLC with electrochemical detection. The utility of this approach is that components of vitreous humor can be identified by their retention time and by their characteristic response when the voltages of the two sensing electrodes are progressively brought together. Four compounds regarded as functional antioxidants in the animal kingdom were identified and quantitated. Other antioxidants known to be present in several biological fluids are not present at detectable or significant levels in vitreous humor; metabolites or precursors of these might be present in trace quantities.