Estr-4-ene-3,17-dione

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted May 26, 1983

Deviations:

yes

Remarks:

Justification why the confirmation of the negative result is not considered necessary is not provided.

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Estr-4-ene-3,17-dione

EC Number:

211-995-8

EC Name:

Estr-4-ene-3,17-dione

Cas Number:

734-32-7

Molecular formula:

C18H24O2

IUPAC Name:

estr-4-ene-3,17-dione

Test material form:

other: solid

Method

Target gene:

Histidine gene locus

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced male rat liver S9 mix

Test concentrations with justification for top dose:

10.0, 33.3, 100.0, 333.3, 1000.0, 2500.0 and 5000.0 µg/plate

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: without metabolic activation: Sodium azide, 4-Nitro-o-phenylenediamine, Methyl methane sulfonate; with metabolic activation: 2-Aminoanthracene

Details on test system and experimental conditions:

plate incorporation assay

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Slight precipitation of the test article occurred on the plates at 5000 µg/plate. Automatic colony counting was not affected.

Toxic effects, evident as a reduction in the number of revertants, occurred in all strains with metabolic activation at 2500 and 5000 µg/plate. In the absence of metabolic activation all strains except TA 98 showed these toxic effects at a concentration of 2500 µg/plate. At the maximal concentration of 5000 µg/plate toxicity of the test article is seemingly reduced in all strains except in TA 98 where strong toxic effects occurred.

Any other information on results incl. tables

Toxic effects, evident as a reduction in the number of revertants, occurred in all strains with metabolie activation at 2500 and 5000 µg/plate. In the absence of metabolie activation all strains except TA 98 showed these toxic effeets at a concentration of 2500 µg/plate. At the maximal concentration of 5000 µg/plate toxicity of the test article is seemingly reduced in all strains except in TA 98 where strong toxic effects occurred. No substantial increases in revertant colony numbers of any of the five tester strains were observed following treatment with the test substance at any concentration level, either in the presence or absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance. Appropriate control mutagens were used as positive controls. They showed a distinct increase in induced revertant colonies. The number of spontaneous revertants in the negative control of strain TA 98 is little lower than the historical range in 1994 (15 colonies versus a range of 17 - 45 colonies). This effect was judged as biologically irrelevant since small fluctuations of the number of spontaneous revertants are common in the bacterial assay system used and the number is within the historical range of negative controls in 1993.

Applicant's summary and conclusion

Conclusions:

In this bacterial reverse mutation assay no evidence of mutagenic activity was seen up to the maximum recommended dose level of 5000 µg/plate in the presence and absence of metabolic activation. There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance. Therefore, norandrostendione was considered to be non-mutagenic in the Salmonella typhimurium reverse mutation assay.

Executive summary:

The mutagenic potential of Norandrostendione was evaluated in a Salmonella/microsome test with the S. typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 in the presence and absence of S9 mix according to OECD TG 471 using the plate incorporation test.

The assay was performed in one experiment with and without liver microsomal activation.

Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations:

10.0; 33.3; 100.0; 333.3; 1000.0; 2500.0; and 5000.0 µg/plate

Toxic effects, evident as a reduction in the number of revertants, occurred in all strains with and without metabolic activation at high concentrations.

No substantial increases in revertant colony numbers of any of the five tester strains were observed following treatment with the test item at any dose level, either in the presence or absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

Appropriate control mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Therefore, Norandrostendione is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.