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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / micronucleus study
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1984
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No guideline cited but according to published method
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1984
Report Date:
1984

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Method according to Clive, D. and Spector, J. (1975). Laboratory procedure for assessing specific locus mutations at the TK locus in cultures L5178Ylymphoma cells. Mutation Research 31, 17 - 29.
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
Batch no. 4356

Method

Target gene:
TK -locus
Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
heterozygous subline , TK +/- obtained from Dr. D. Clive
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9 from Aroclor induced rat livers
Test concentrations with justification for top dose:
without metabolic activation: 0, 1.28, 2.56, 5.12, 10.25, 20.5 micrograms/ml
with metabolic activation: 0, 4.17, 8.33, 16.67, 33.35, 66.7 microgram/ml
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
Migrated to IUCLID6: 0.75 microgram/ml
Details on test system and experimental conditions:
Preliminary cytotoxicity test: highest concentration for mutagenicity assay causes 85% growth reduction after 4-hour treatment and 72 -hour suspension growth. Cells were grown in Fishers medium F10, with 10% horse serum. Final DMSO concentration was always < 1%.
Cells were exposed for 4 hours at seven concentrations of 15.63 - 1000 micrograms/ml. Total growth inhibition (cytotoxicity) achieved at 250 micrograms/ml within 48 hours.
Main experiment: 3 x 105 cells were seeded per culture and were treated for 4 hours with TGMDA in the presence or absence of S9 activating liver enzymes, followed by a growth period of 3 days without exposure. After this expression phase cells were plated in soft-agar in petri-dishes containing 50 micrograms/ml of BUdR, and additional 14 days of incubation followed. With a colony counter the colonies were counted .
The results are expressed as number of induced TK-/- mutants/106 cells.
Evaluation criteria:
To be a positive result, the colony count of the treated plates has to be 2.5 times higher than the solvent control.
Statistics:
no statistical methods were applied

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
3 tests without metabolic activation and one test with metabolic activation was performed. In all experiments the highest concentration yielded the highest amount of mutant colonies, but at growth rates of 0.3 - 1.7 % (or cytotoxicity of >98%). (see tables)
Nevertheless, the result was consitant throughout the three experiments and was judged to be positive.
Remarks on result:
other: strain/cell type: not determined
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive

Under the conditions of the test in mouse lymphoma cells, the product TK 10884 was mutagenic with and without S9-activating enzymes.
Executive summary:

Under the conditions of the test in mouse lymphoma cells, the product TK 10884 was mutagenic with and without S9-activating enzymes.