Registration Dossier

Administrative data

Endpoint:
in vivo mammalian germ cell study: gene mutation
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:
data from handbook or collection of data

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
The sex-linked recessive lethal test for mutagenesis in Drosophila melanogaster
Author:
W.R. Lee (Leader), S. Abrahamson, R. Valencia, E.S. von Halle, F.E. Wurgler and S. Zimmering
Year:
1983
Bibliographic source:
Mutation Research, 123 (1983) 183-279 REVIEW
Reference Type:
publication
Title:
Gene mutation in vivo toxicity study of the test chemical
Author:
Lee et al
Year:
1983
Bibliographic source:
Mutation Research

Materials and methods

Principles of method if other than guideline:
The test for sex-linked recessive lethals (SLRL) in Drosophila melanogaster is used to detect induced mutations. The advantage of the test for both screening and hazard evaluation is its objectivity in testing for transmissible mutations in various chemicals. One of the chemicals studied include the test chemical of interest.
GLP compliance:
not specified
Type of assay:
Drosophila SLRL assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: N Butylated hydroxyanisole
- Molecular formula : C11H16O2
- Molecular weight: 181.2533 g/mol
- Substance type: Organic

Test animals

Species:
Drosophila melanogaster
Strain:
other: Balancer strains: Suitably marked inverted X chromosomes Tester strains: Males from wild type strains Oregon-K, Oregon-R, Canton-S, and Berlin-K.
Sex:
male

Administration / exposure

Route of administration:
oral: feed
Vehicle:
Vehicles
- Vehicle(s)/solvent(s) used: Test chemical is dissolved in either DMSO or ethanol

- Justification for choice of solvent/vehicle: DMSO is a commonly used solvent, while ethanol has an advantage since the flies have large quantities of the alcohol dehydrogenase (ADH) enzyme and can readily metabolize ethanol.

- Concentration of test material in vehicle: No data available

- Amount of vehicle (if gavage or dermal): No data available

- Type and concentration of dispersant aid (if powder): No data available

- Lot/batch no. (if required): No data available

- Purity: No data available

OTHER INFORMATION: In a test to screen for mutagenicity of a chemical, a single concentration of the chemical may be used to test for SLRLs. The selection of the final test concentration should be preceded by one or more exposure range-finding experiments in which two points are studied:
1. Toxicity to the males during treatment and during the breeding for the mating pattern analysis; and
2. Sterilizing effect due to lethal damage to one or several germ cell stages.

Based on the results obtained in such studies, a convenient exposure may be selected, usually at the LD50 level for treated males, provided sterility does not create problems. If sterility is induced, a lower exposure may have to be used. If no adverse effects are detected, the highest technically feasible exposure at which the flies will feed should be used.
Details on exposure:
For oral route
PREPARATION OF DOSING SOLUTIONS: No data available

DIET PREPARATION
- Rate of preparation of diet (frequency): No data available

- Mixing appropriate amounts with (Type of food): No data available

- Storage temperature of food: No data available
Duration of treatment / exposure:
No data
Frequency of treatment:
No data
Post exposure period:
No data
Doses / concentrations
Remarks:
No data
No. of animals per sex per dose:
No data
Control animals:
yes, historical
Positive control(s):
Yes, nonconcurrent positive control with ethylmethanesulphonate (EMS) or diethylnitrosamine (DEN)

Justification for choice of positive control(s): Nonconcurrent positive control are satisfactory for routine recessive lethal tests

- Route of administration: No data available

- Doses / concentrations: No data available

Examinations

Tissues and cell types examined:
Eye shape and eye color
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: No data available

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): No data available

DETAILS OF SLIDE PREPARATION: No data available

METHOD OF ANALYSIS:
Hazard evaluation has been made using dose to the germ cells of ionizing radiation, and similar use of this test system with chemical mutagens is possible with the development of dosimetry of chemical mutagens (Comment: I don’t think this statement is correct, however, I am not sure what to state here since there is no real directions on methods of analysis in the report text.)

OTHER: No data available
Evaluation criteria:
Statistical evaluation
Statistics:
1. Comparison of control and treated frequencies
The most common problem is a comparison of the mutation frequencies obtained in a control and in a treated group. As long as the total number of mutations recovered (control and treated) is below 100, the Kastenbaum-Bowman test should be used. If more than 100 mutations are obtained, the chi square test is appropriate.

2. Analysis of the pattern of successive matings
The pooling of data from submatings is one by adding the number of chromosomes tested and the number of mutations found. In this way a weighted mean is obtained. For each of the samples, the statistical significance of a difference between the mutation frequency found in the control and in the treated groups should be checked as described above.
In a second step, the same procedure is repeated to obtain the analysis of the data pooled from the two samples.

3. Dose-response data
Dose-response data can be analyzed using standard regression techniques when germ cell dosimetry is available.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
not specified
Negative controls validity:
other: Yes, solvent (If used) without the test chemical (administered in the same way as the treatment) is used for the negative control.
Positive controls validity:
other: Nonconcurrent positive control
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: No data available
- Solubility: No data available
- Clinical signs of toxicity in test animals: No data available
- Evidence of cytotoxicity in tissue analyzed: No data available
- Rationale for exposure: No data available
- Harvest times: No data available
- High dose with and without activation: No data available
- Other: No data available

RESULTS OF DEFINITIVE STUDY
- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): No data available
- Induction of micronuclei (for Micronucleus assay): No data available
- Ratio of PCE/NCE (for Micronucleus assay): No data available
- Appropriateness of dose levels and route: No data available
- Statistical evaluation: No data available

Applicant's summary and conclusion

Conclusions:
The test chemical is regarded to be negative for any mutagenic response when a SLRL test carried out on male Drosophila melanogaster.
Executive summary:

Drosophila melanogaster was tested in a test for sex-linked recessive lethals (SLRL) to detect induced mutations. Ten day germ cell-staged adult male flies were fed with a solvent containing the test chemical to detect if it induced any mutagenic responses. No mutagenic responses were detected when a SLRL test was carried out on Drosophila melanogaster.