Influence of Mycoplasma arginini infection on the induction of aryl hydrocarbon hydroxylase by TCDD in rat hepatoma cell cultures.

Mycoplasma arginini was eliminated from a rat hepatoma cell line (H-4-II-E) by plating at low cell density and treatment with chlortetracycline (250 micrograms/ml), kanamycin (250 micrograms/ml), tylosin (100 micrograms/ml), 3% M. arginini antiserum and 5% fresh guinea-pig serum. The induction of AHH activity in the cell culture was measured in response to increasing concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The ED50 values (estimated doses that produce 50% maximum enzyme induction) were calculated to be 0.256, 0.452 and 0.344 pmol TCDD/plate for original, mycoplasma-free and reinfected cells, respectively. Although the absence of M. arginini in the rat hepatoma cell line makes the cells slightly less responsive to AHH induction by TCDD, this decrease does not detract from the use of the method to screen food extracts and environmental samples for the presence of certain toxic planar organic compounds.