Pentane-2,4-dione

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: Meets generally accepted scientific standards, well documented and acceptable for assessment.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1985

Reference 2

Reference Type:

secondary source

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Principles of method if other than guideline:

Preliminary trials were performed to determine an appropriate range of test concentration in which the highest concentration would kill no more than 90 % of the treated CHO cells. In this preliminary experiment concentrations above 2.0 mg/mL in the presence of S9 and 3.0 mg/mL in the absence of S9 virtually killed all cells. All incubations were run in duplicate. Cells were exposed to at least five concentrations which allowed sufficient cell survival for assessment of survival and quantification of mutants. Cells were exposed for 5 h in tests both with and without metabolic activation. The mutant fraction was determined after a 9 to 12 day subculturing period to allow expression of the mutant phenotype. Metabolic activation was applied by S9 liver homogenate, prepared from Aroclor 1254-induced, Sprague-Dawley male rats.

GLP compliance:

yes

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Details on test material:

Purity: 99.2%
Lot No.: S-050082

Method

Target gene:

HPRT

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

CHO-K1-BH4 (subclone D1)

Metabolic activation:

with and without

Metabolic activation system:

S9-Mix from livers of Sprague-Dawley rats pretreated with Aroclor 1254

Test concentrations with justification for top dose:

Without S9-mix: 0.005-1.5 mg/mL
Wit S9-mix: 0.005-1.0 mg/mL

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: ethylenemethanesulfonate (200 µg/mL)

Details on test system and experimental conditions:

DURATION
- Exposure duration: 5 h
- Expression time (cells in growth medium): 9-12 days

NUMBER OF REPLICATIONS: incubations were run in duplicates

SURVIVING FRACTION:
Determination 18-24 hrs after removal of the test chemical using 4 plates/culture and 100 cells per plate.

MUTANT FRACTION:
200000 cells per plate in 5 plates per dose in selective medium.
Plating efficiency in non-selective medium: 4 plates/dosed culture with 100 cells/plate.

DETERMINATION OF CYTOTOXICITY
- Method:
other: Preliminary test where number of live cells was investigated (no data about applied method given)

Statistics:

After tranformation of the mutation frequencies (MF) according to the conversion method of Box and Cox (1964), CHO data were analyzed according to Snee and Irr (Snee, R .D. und J .D . Irr, Mutation Research . 85 (1981), 77-93).

Results and discussion

Test results

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: Only data from a preliminary test are available. The concentrations used should give at least 10% survival at the highest concentration used.

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

2,4-Pentanedione did not produce any reproducible or statistically significant increases in the incidences of mutations of CHO cells at concentrations between 0.005 to 1.5 mg/mL in tests without an S9 metabolic activation system or from 0.005 to 1.0 mg/mL with S9-mix. Random cultures with increased mutant values were within the typical range of variability for this test in the investigating laboratory and the increases were not reproducible in the duplicate cultures/dose level. 2,4-Pentanedione was not considered to be an active gene mutagen under the conditions of the CHO test system.

Applicant's summary and conclusion

Conclusions:

Under the evaluated conditions no increased mutation frequency was observed. The result was evaluated to be negative.

Executive summary:

2,4-Pentanedione did not produce any reproducible or statistically significant increases in the incidences of mutations of CHO cells at concentrations between 0.005 to 1.5 mg/mL in tests without an S9 metabolic activation system or from 0.005 to 1.0 mg/mL with S9-mix. Random cultures with increased mutant values were within the typical range of variability for this test in the investigating laboratory and the increases were not reproducible in the duplicate cultures/dose level. 2,4-Pentanedione was not considered to be an active gene mutagen under the conditions of the CHO test system.