Newer diagnostic procedures in chronic toxicity studies in rats.

A large number of diagnostic procedures which are either adapted from clinical laboratory tests or are based on pharmacological and biochemical concepts are available for introduction into routine animal toxicology. In order to illustrate the variety of possible experimental approaches several examples are given, ranging from simple determinations of bleeding time and fibrinolysis to cardiovascular function studies including serial electrocardiography, measurement of the cardiac output and the catecholamine-arrhythmia threshold. Moreover, the use of serial fine needle aspiration biopsy for early diagnosis of various liver lesions is described. It is stressed that these diagnostic procedures should not be included indiscriminately into the classical toxicological programs, but should be used judiciously to test a clearly stated scientific hypothesis.