TY - JOUR
T1 - Application, limitations and research requirements of in vitro test systems in toxicology
AU - Greim, H.
AU - Andrae, U.
AU - Forster, U.
AU - Schwarz, L.
PY - 1986
Y1 - 1986
N2 - There is increasing application of in vitro-test systems for toxicological evaluation of chemicals, which became possible by increasing understanding of the biological endpoints present in such systems and their capability for metabolic activation and inactivation. This communication focusses on the capacities of metabolic activation and inactivation in mutagenicity test systems, using bacteria, mammalian cells in culture and isolated hepatocytes. Bacterial test procedures with S-9-fraction are specific metabolic activation systems with low inactivation capacity. Mammalian cells are either deficient in metabolic activities or contain only limited activation capacity although special cell lines derived from hepatoma cells express certain metabolic activation as well as inactivation reactions. Isolated hepatocytes contain enzymatic activities similar to those in the intact liver, which however decrease at different rates. It is the goal of present research to construct cell lines with defined and sufficient activities of these enzymes. In isolated hepatocytes chemically induced DNA repair can be readily detected when a clear discrimination between mitochondrial, semiconservative and repair synthesis is provided. In such systems genotoxicity of reactive oxygen species is decreased by physiological concentrations of alpha-ketoacids, pyruvate possessing the highest antioxidant activity. It is concluded that in vitro test systems provide a suitable tool for detecting genotoxic and toxic effects of chemicals. However, many biological parameters such as metabolic activity, degree of differentiation of the cells, cofactor requirement, and composition of the medium affect the reliability of the test system. Thus, only a detailed understanding of the biology and biochemistry of such test allow production of reliable and reproducible results.
AB - There is increasing application of in vitro-test systems for toxicological evaluation of chemicals, which became possible by increasing understanding of the biological endpoints present in such systems and their capability for metabolic activation and inactivation. This communication focusses on the capacities of metabolic activation and inactivation in mutagenicity test systems, using bacteria, mammalian cells in culture and isolated hepatocytes. Bacterial test procedures with S-9-fraction are specific metabolic activation systems with low inactivation capacity. Mammalian cells are either deficient in metabolic activities or contain only limited activation capacity although special cell lines derived from hepatoma cells express certain metabolic activation as well as inactivation reactions. Isolated hepatocytes contain enzymatic activities similar to those in the intact liver, which however decrease at different rates. It is the goal of present research to construct cell lines with defined and sufficient activities of these enzymes. In isolated hepatocytes chemically induced DNA repair can be readily detected when a clear discrimination between mitochondrial, semiconservative and repair synthesis is provided. In such systems genotoxicity of reactive oxygen species is decreased by physiological concentrations of alpha-ketoacids, pyruvate possessing the highest antioxidant activity. It is concluded that in vitro test systems provide a suitable tool for detecting genotoxic and toxic effects of chemicals. However, many biological parameters such as metabolic activity, degree of differentiation of the cells, cofactor requirement, and composition of the medium affect the reliability of the test system. Thus, only a detailed understanding of the biology and biochemistry of such test allow production of reliable and reproducible results.
UR - http://www.scopus.com/inward/record.url?scp=0022895351&partnerID=8YFLogxK
M3 - Article
C2 - 3545145
AN - SCOPUS:0022895351
SN - 0340-5761
VL - 59
SP - 225
EP - 236
JO - Archives of Toxicology
JF - Archives of Toxicology
IS - SUPPL. 9
ER -