Dynamic Phase of Toxicant Action

FIGURE 2.16 Illustration of the kinetic phase of metabolism for toxicants and protoxicants. In this phase, a protoxicant may be metabolically converted to a toxic species. A toxicant may be detoxified and excreted without doing harm, remain unchanged as an active parent compound that may have a toxic effect, or converted to another active metabolite that is potentially toxic. 

A typical primary reaction is the binding of carbon monoxide, CO, with blood hemoglobin designated Hb  

A biochemical response to carbon monoxide exposure is deprivation of tissues of O2 needed to carry out metabolic processes. In this case, brain cells are deprived of oxygen, the subject may lose consciousness, and permanent brain damage or death may result. An observable effect of carbon monoxide poisoning may range from lethargy through unconsciousness and even death. 

Among the numerous biochemical effects that may result from the binding of a toxicant to a receptor, one of the most common is impairment of enzyme function. This may occur as the result 

Examples of Target Systems, Toxicants, and Effects of Toxic Substances 

---

Figure 12. The dynamic phase of toxicant action (Mcmahan, 1994).

---