The In Vitro Approach to Teratogenicity Testing

Abstract

Investigations in toxicology may be divided into those in which the primary aim is to identify hazardous substances (e.g. toxicity testing) and those where the mechanism of toxicity is the object of study. There is, of course, much overlap between the two approaches and they are mutually interdependent, but the distinction is useful to define the scope of this chapter. The goal of toxicity testing is to identify hazardous agents, to define the conditions (dose, time, route of exposure, susceptible species, etc.) under which they will exert their toxicity and to estimate the potential effects on human health. This chapter will review those in vitro systems which have potential application as tests for the identification of teratogenic substances. That is not to suggest that studies of the mechanisms of teratogenicity are not of paramount importance. Knowledge of toxic mechanisms may allow the prediction of toxicity, based upon chemical structure or reactivity, and may also permit preventive, ameliorative or curative measures to be devised. As will be discussed, suitable in vitro test systems cannot be defined without considering the mechanism of toxicity.