3,5,5-trimethylcyclohex-3-en-1-one

Genetic toxicity: in vitro

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Responses of the L5178Y tk+/tk- mouse lymphoma cell forward mutation assay: III. 72 coded chemicals.

Author:

McGregor DB, Brown A, Cattanach P, Edwards I, McBride D, Riach C, Caspary WJ

Year:

1988

Bibliographic source:

Environ Molec Mutagen 2: 85-154

Reference 2

Reference Type:

review article or handbook

Title:

Toxicology and Carcinogenesis Studies of Isophorone in F344/N Rats and B6C3F1 Mice.

Author:

NTP (U.S. National Toxicology Program)

Year:

1986

Bibliographic source:

Techn Rep Ser No. 291, U.S. Department of Health and Human Services

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Clive and Spector, Mutat. Res. 44, 269-278 (1975) and Clive et al., Mutat. Res. 59, 61-108 (1979)

GLP compliance:

not specified

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3,5,5-trimethylcyclohex-2-enone

EC Number:

201-126-0

EC Name:

3,5,5-trimethylcyclohex-2-enone

Cas Number:

78-59-1

IUPAC Name:

3,5,5-trimethylcyclohex-2-en-1-one

Details on test material:

- Analytical purity: 97%, 0.3% water
- Origin: Leidy Chemical Corporation

Method

Target gene:

TK

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Test concentrations with justification for top dose:

50 - 1600 µg/mL (details see Test Conditions)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Details on test system and experimental conditions:

Experiments were performed twice, and all doses were tested in duplicate, except the solvent control (DMSO), which was tested in quintuplicate. Cells (6 x 10E+5/mL) were treated for 4 hours at 37 ºC in medium, washed, resuspended in medium, and incubated for 48 hours at 37 ºC. After expression, 3 x 10E+6 cells were plated in medium supplemented with trifluorothymidine for selection of cells that were mutant at the thymidine kinase (TK) locus, and 600 cells were plated in nonselective medium to determine the percentage of viable cells.
Trial 1: 0, 50, 100, 200, 400, 800, 1600 µg/mL
Trial 2: 0, 400, 600, 800, 1000, 1200 µg/mL
Trial 3: 0, 200, 400, 600, 800, 1000 µg/mL

Results and discussion

Test results

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1600 µg/mL

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

GENOTOXIC EFFECTS
Without metabolic activation: mutagenic. Isophorone was toxic to the cultures only at moderately high concentrations.
Significant increases in mutant fraction occurred in all three experiments, accompanied by a reduction of relative total growth (RTG).

The lowest effective concentration was 400 µg/mL in the first experiment, where there was apparently no reduction in RTG from the vehicle control level.
In the second experiment, only at 600 µg/mL there was evidence of toxicity.
The lowest effective concentration in this experiment was 800 µg/mL. However, the cloning efficiency was low in this experiment (results questionable). In the third experiment the lowest effective concentration was 800 µg/mL.

Tennant et al. (1997) judged isophorone as positive at concentrations >= 400µg/L without metabolic activation.

CYTOTOXICITY
Relative total growth reduced at 800, 1000 and 1200 µg/mL.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.