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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2013

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
mammalian cell gene mutation assay

Test material

Method

Target gene:
HPRT
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
1st Experiment
without S9 mix (4-hour exposure period)
0; 25.0; 50.0; 100.0; 200.0; 400.0; 800.0 μg/mL
with S9 mix (4-hour exposure period)
0; 6.3; 12.5; 25.0; 50.0; 100.0; 200.0; 400.0 μg/mL
2nd Experiment
without S9 mix (24-hour exposure period) (discontinued due to lacking cytotoxicity)
0; 10.9; 21.9; 43.8; 87.5; 175.0; 350.0 μg/mL
with S9 mix (4-hour exposure period)
0; 15.6; 31.3; 62.5; 125.0; 250.0; 400.0 μg/mL
3rd Experiment
without S9 mix (24-hour exposure period)
0; 46.9; 93.8; 187.5; 375.0; 750.0; 1 500.0 μg/mL
Vehicle / solvent:
water
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
7,12-dimethylbenzanthracene
ethylmethanesulphonate
Details on test system and experimental conditions:
according to guideline
Evaluation criteria:
according to guideline
Statistics:
according to guideline

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

It can be stated that under the experimental conditions reported the test item did not induce gene mutations at the HPRT locus in CHO cells.
Executive summary:

The substance L-Glutamic acid, N-coco acyl derivs., disodium salts was assessed for its potential to induce gene mutations at the hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus in Chinese hamster ovary (CHO) cells in vitro. Three independent experiments were carried out, with and without the addition of liver S9 mix from phenobarbital- and β- naphthoflavone induced rats (exogenous metabolic activation). In an initial range-finding cytotoxicity test(s) the experimental doses of the main

experiments were determined.

The vehicle controls gave mutant frequencies within the range expected for the CHO cell line. Both positive control substances, EMS and DMBA, led to the expected increase in the frequencies of forward mutations.

In this study, in the 1st Experiment in the absence and presence of metabolic activation and in the 2nd Experiment in the presence of metabolic activation the highest concentrations tested for gene mutations were clearly cytotoxic. However, in the 2nd Experiment in the absence of metabolic activation no cytotoxicity was observed up to the highest applied concentration. Therefore, a 3rd Experiment was performed which showed clearly reduced colony numbers at least at the highest concentrations.

Based on the results of the present study, the test substance did not cause any relevant increase in the mutant frequencies either without S9 mix or after the addition of a metabolizing system in three independent experiments.

Thus, under the experimental conditions of this study, the test substance L-Glutamic acid, N-coco acyl derivs., disodium salts is not mutagenic in the HPRT locus assay under in vitro conditions in CHO cells in the absence and presence of metabolic activation.