The dilemma of oxidative stress personified by the diprosopus 8-iso-prostaglandin F2α and prostaglandin F2α

In general, the term “oxidative stress” describes an imbalance between oxidants and antioxidants in favor of the oxidants. While antioxidant defense is widely accepted to involve both enzymatic and non-enzymatic reactions, oxidants are generally assumed to be produced by non-enzymatic processes involving chemically produced free radicals. However, many oxidants are also formed by numerous enzymes and proteins. The F2-isoprostane 8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA) are widely used as biomarkers of oxidative stress, although there is evidence that both 8-iso-PGF2α and MDA are also produced enzymatically from arachidonic acid by the action of cyclooxygenase (COX). On the contrary, there is also evidence that PGF2α is produced from arachidonic acid both by the action of COX and non-enzymatically. The duality of oxidative stress, personified by 8-iso-PGF2α and PGF2α, is a serious dilemma and demands new definitions and strategies from the scientists.