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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1977

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
not specified
Principles of method if other than guideline:
- Principle of test: Standard plate incorporation assay (Ames, 1975)
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
N,N-dimethylformamide
EC Number:
200-679-5
EC Name:
N,N-dimethylformamide
Cas Number:
68-12-2
Molecular formula:
C3H7NO
IUPAC Name:
N,N-dimethylformamide
Details on test material:
N,N-dimethylformamide, no further data

Method

Target gene:
his-
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
DNA polymerase A deficient
Species / strain / cell type:
S. typhimurium TA 1538
Additional strain / cell type characteristics:
DNA polymerase A deficient
Metabolic activation:
with and without
Metabolic activation system:
Type and composition of metabolic activation system:
- Ames test with and without metabolic activation with S-9 mix prepared from liver homogenate of Aroclor pre-treated male Sprague-Dawley rats.
Test concentrations with justification for top dose:
9400, 24000, 47000, 94000, 190000, 470000 µg/plate
Controlsopen allclose all
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene
Remarks:
In the assay with metabolic activation. Tested in concentrations of 5, 10 and 100 µg/plate
Positive controls:
yes
Positive control substance:
other: N-Methyl-N'-nitro-N-nitrosoguanidine
Remarks:
In the assay without metabolic activation. Tested in 2 µg/plate (TA1535, TA100)
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
In the assay without metabolic activation. Tested at 50 µg/plate (TA1537).
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
In the assay without metabolic activation. Tested at 25 µg/plate (TA1538 and TA98).
Negative solvent / vehicle controls:
yes
Remarks:
A negative control run in parallel in the assay with and without metabolic activation.
Details on test system and experimental conditions:
TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: Plates are incubated at 37 °C for 48 hours.

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- toxicity indicated by sparse background lawn
Rationale for test conditions:
Cytotoxicity of the test sample as measured in strain TA1535 is the basis for selecting concentrations to be used in the present test. Concentrations of test sample that give less than 50 % of control survival are normally not selected for the assay.
Evaluation criteria:
Evaluation criteria: a chemical was classified as non-mutagenic if the reversion frequency was less than 2 times the spontaneous frequency.
Statistics:
No statistical analysis was performed. However, in the present assay 470000 µg/plate was chosen because this experiment was done to aid in evaluating a recent Utah Biological Testing Service report, that concluded that DMF is mutagenic in 4 of the Ames strains of Salmonella typhimurium.

Results and discussion

Test results
Species / strain:
other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
DMF is not mutagenic even at concentrations that are cytotoxic.
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at 190000 and 470000 µg/plate without metabolic activation and at 470000 µg/plate with metabolic activation.

Any other information on results incl. tables

DMF is not mutagenic even at concentrations that are cytotoxic. Cytotoxicity occurred at 190000 and 470000 µg/plate without metabolic activation and at 470000 µg/plate with metabolic activation.

Positive and negative controls did work well in the present investigation.

Applicant's summary and conclusion

Conclusions:
DMF is not mutagenic even at concentrations that are cytotoxic.
Executive summary:

Study design

This non-GLP study is an in vitro gene mutation test in bacteria, conducted similar to OECD Guideline 471 (Bacterial Reverse Mutation Assay). The Ames test was performed with and without metabolic activation with S-9 mix prepared from liver homogenate of Aroclor pre-treated male Sprague-Dawley rats. The Plates are incubated at 37 °C for 48 hours.

Cytotoxicity of the test sample as measured in strain TA1535 is the basis for selecting concentrations to be used in the present test. Concentrations of test sample that give less than 50 % of control survival are normally not selected for the assay.

Results

Using S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100 DMF is not mutagenic even at concentrations that are cytotoxic (Cytotoxicity occurred at 190000 and 470000 µg/plate without metabolic activation and at 470000 µg/plate with metabolic activation). Positive controls (with metabolic activation: 2 -Aminoanthracene and without metabolic acitvation: N-Methyl-N'-nitro-N-nitrosoguanidine; 9-Aminoacridine; 2-Nitrofluorene) and the negative control did work well in the present investigation.

Conclusion

DMF is not mutagenic even at concentrations that are cytotoxic.