Toxicodynamic Tests

Abstract

Toxicodynamic testing is aimed at the elucidation of adverse effects of chemicals including understanding of their mode of action. In many cases, the “standard program” of toxicological testing on acute, subchronic, or chronic toxicity, genotoxicity, carcinogenicity, teratogenicity, and developmental and reproductive toxicity, which is needed for many regulatory purposes, already provides important information on the mode(s) of action of a compound. Targeted mechanistic investigations often follow, which use specifically designed models such as genetically modified cells or animals, studies using specific cell types, subcellular fractions, enzymes, etc. The understanding of the mechanisms underlying a certain mode of action and gained information on the dose- or concentration-response from in vivo or in vitro studies is crucial to derive point of departures for further human risk assessment and for regulatory toxicology of chemicals since it allows decisions on the options for extrapolation of experimental data to the human situation. This text follows the different levels of experimental models in toxicodynamic testing from isolated target molecules up to whole organisms like laboratory animals and humans.