ABSTRACT
The discussion of effects of chemicals as a result of exposure to a particular dose (Chapter 6) necessarily must be followed by a discussion of the path by which that dose elicits that response. This relationship has traditionally been known as the doseresponse relationship.* The result of exposure to the dose can be any measurable, quantiÞable, or observable indicator. The response depends on the quantity of chemical exposure or administration within a given time period. Two types of doseresponse relationships exist, depending on number of subjects and doses tested. The graded dose-response describes the relationship of an individual test subject or system to increasing and/or continuous doses of a chemical. Figure 7.1 illustrates the effect of increasing doses of several chemicals on cell proliferation in vitro. The concentration of the chemical is inversely proportional to the number of surviving cells in the cell culture system.
