Cytochrome P450 Oxidoreductase as an Underappreciated Biomarker of Xenobiotic Exposure

This review summarizes current scientific data on the potential of cytochrome P450 oxidoreductase as a biomarker for xenobiotic exposure and for assessing the biological effects of chemical pollution. It examines the molecular and biochemical mechanisms underlying CYPOR function, its role in supporting the activity of microsomal cytochrome P450 enzymes, and the regulation of its expression and enzymatic activity in response to various xenobiotics. Drawing on literature from environmental toxicology, biochemistry, pharmacology, and molecular genetics, the review synthesizes findings from experimental and field studies involving fish, invertebrates, insects, and mammals. Particular attention is given to the use of CYPOR in the biomonitoring of aquatic ecosystems, including the correlation between its levels and histological or hematological indicators of toxic stress. The primary methods for measuring CYPOR are analyzed. The review also addresses limitations in using this biomarker, stemming from interspecies differences, the influence of confounding stressors, and the lack of standardized analytical protocols. The potential for incorporating CYPOR into comprehensive biomarker panels for environmental monitoring, evaluating the efficacy of conservation measures, and advancing personalized pharmacology is discussed. Finally, the review identifies priority areas for future research, which are essential for the standardization and validation of CYPOR as a biomarker.