Morphological Endpoints in In Vitro Testing

Before starting the in vitro testing of potentially toxic or teratogenic substances goal and purpose of the investigations must be known. Only then are an exact planning of the experiments and the choice of appropriate methods possible. This also includes the definition of endpoints, i.e. parameters and functions that are to be measured in dependence on time. These endpoints may comprise special individual aspects or steps of cell metabolism or the more general behaviour of the cells, in other words the sum of individual steps. In the first case we are confronted with a vast amount of individual parameters, i.e. endpoints, which explains why the right choice is of such importance. In the second case we investigate the sums of individual functions which are, therefore, less specific and allow fewer conclusions as to the elucidation of the modes of action. This group includes, among others, the investigation of cytotoxicity or plating efficiency. — The study of an influence on or lesion of the genome requires other techniques that will not be discussed in this connection.