ABSTRACT
This chapter focuses on the possible uses for metabolites of xenobiotic chemicals and endogenous metabolites as biomarkers of exposure to xenobiotic chemicals. The discussion on metabolites of xenobiotic chemicals considers animals only, while that on endogenous metabolites includes both animals and plants. Metabolites bound to hemoglobin may be of use as a biomarker. Plant metabolites of potential interest as environmental stress biomarkers include glutathione, phytochelatins, polyamines, and stress ethylene. A variety of factors such as reproductive state, temperature, and dietary status can affect metabolite production. A number of xenobiotic chemicals undergo metabolism to highly reactive electrophilic intermediates that can bind covalently to cellular macromolecules. The metabolites of xenobiotic chemicals may accumulate to high levels in certain tissues or body fluids or bind to specific tissue macromolecules in a manner that facilitates detection of exposure and indicates potential harm to the organism.
