Probe of metabolic activation

These studies demonstrated that DNA-binding can be a reliable probe of metabolic activation. In contrast to studies of metabolites per se, which usually involve large numbers of metabolite intermediates, DNA-binding monitors only chemically reactive metabolites. Also, if there is no selective repair of specific adducts, DNA-binding monitors the cumulative production of metabolites over time, while direct measurement of metabolites can show the metabolite spectrum only at the time observed. This can be particularly critical for studies of activation of complex chemicals such as polycyclic aromatic hydrocarbons whose primary metabolites are subject to secondary and tertiary metabolism (8). 

When expressed graphically over the 120-h period of the culture, it can be seen in Figure 29 drawn from Equation (22) and Equation (23) that heat flux is a monotonically increasing function of these ratios and therefore an apparently valid probe of metabolic activity. 

---