Investigations on the detection of mutagenic activity of beef extract in rats after oral administration.

After oral administration of beef extract the body fluids of Aroclor-treated and untreated rats were investigated for mutagenicity using the Salmonella/microsome test. In the stomach contents, the bile and the urine of the animals, mutagenic activity was discovered after S-9 activation. Although the mutagenic substances must have been transported by the blood stream to the excreting organs no increased mutagen-induced his+ revertants were observed in venous blood. Direct-acting mutagens were not detected in the tested body fluids, either in the Aroclor-treated rats or in the untreated ones.