Comparison of rat liver S-9 activity induced with aroclor-1254 and phenobarbital/{beta}-naphthoflavone in microbial and CHO/HGPRT mutation assays
- SITEK Research Laboratories, Rockville, MD (United States)
There is an intense interest in alternatives to Aroclor-1254 (PCB) for induction of S-9. Manufacturers no longer produce PCB, and are selling PCB, in stock, with a 30% increase in price. One substitute, a combination of phenobarbital (PB) and {beta}-naphthoflavone ({beta}-NF), has been suggested to be a suitable replacement for PCB. In order to compare the activity of PB/{beta}-NF-induced S-9 with PCB-induced S-9, the two kinds of S-9 were prepared and tested in both Microbial and CHO/HGPRT Mutation Assays. One group of CD rats was treated with PB at 75 mg/kg by I.P. injection for 4 consecutive days and a single dose of {beta}-NF at 80 mg/kg 2 days prior to sacrifice. A second group of CD rats was treated with a single dose of Aroclor-1254 at 500 mg/kg on Day 1 by I.P. injection. All animals were sacrificed on Day 5. A Plate Incorporation Mutation Assay was performed with five Salmonella typhimurium tester strains and one Escherichia coli tester strain. A single dose of 2-Amino-anthracene (2-AA) at 1.25 {mu}g/plate for the five Salmonella typhimurium tester strains and 10 {mu}g/plate for the WP2uvrA tester stain was used as a positive control. DMSO at 0.1 mL/plate was used as a solvent control. In the CHO/HGPRT Gene Mutation Assay, 7, 12-Dimethylbenz ({alpha})anthra-cene (DMBA) was used at 5.0 {mu}g/mL as a positive control. Acetone at 10 {mu}L/mL was used as a solvent control. The results from the Microbial Assay showed that the increase in mean reversion frequency of 2-AA over that of the corresponding solvent control with the PB/{beta}-NF-induced S-9 was greater than the increase from the PCB-induced S-9 for all of the six tester strains. In the CHO/HGPRT Mutation Assay, the results showed that DMBA gave a similar positive response for both the PCB- and PB/{beta}-NF-induced S-9s. The data obtained from these comparative studies supports the suggestion of the authors listed above that PB/{beta}-NF is a suitable substitute for PCB for induction of S-9.
- OSTI ID:
- 115154
- Report Number(s):
- CONF-9503160-; ISSN 0893-6692; TRN: 95:004640-0049
- Journal Information:
- Environmental and Molecular Mutagenesis, Vol. 25, Issue Suppl.25; Conference: 26. annual Environmental Mutagen Society meeting, St. Louis, MO (United States), 12-16 Mar 1995; Other Information: PBD: 1995
- Country of Publication:
- United States
- Language:
- English
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