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Toxicological information

Genetic toxicity: in vivo

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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
Study period:
study conducted under the auspices of the National Toxicology Program (1983)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
publication
Title:
Chemical mutagenesis testing in Drosophila. X. results of 70 coded chemicals tested for the National Toxicology Program
Author:
Foureman P, Mason JM, Valencia R and Zimmering S
Year:
1994
Bibliographic source:
Environ. Molec. Mutagen. 23, 208-227

Materials and methods

Principles of method if other than guideline:
Method: NTP SLRL test method
GLP compliance:
not specified
Type of assay:
Drosophila SLRL assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- origin: Leidy
- lot/batch 1204/01
- analytical purity: 97.2 %

Test animals

Species:
Drosophila melanogaster
Strain:
other: Canton S and Basc stocks
Sex:
male
Details on test animals and environmental conditions:
TEST ORGANISMS: 
- Age: adult
- Origin: Canton S and Basc stocks maintained at Brown University and the  University of Wisconsin

Administration / exposure

Route of administration:
oral: feed
Vehicle:
Solvent: ethanol
Details on exposure:
ADMINISTRATION: 
- Vehicle: ethanol, CAS RN 64-17-5 
- Solutions: two or three glass fiber discs were saturated with the test compound carried in solvent (ethanol) at the bottom of a standard glass vial.
Solutions were renewed at 24 hr and 48 hr.
- Duration of test: first mating after 72 hours of exposure
- Frequency of treatment: 
- Sampling times and number of samples: three broods, for each >= ca.  5000 chromosomes scored unless mutant frequency > 1.0 %
- Control groups and treatment: concurrent solvent (ethanol)

FOLLOW-UP TESTING:
2-3-day-old males were injected with 0.7 % NaCl solution containing the  test chemical at 12,500 ppm. At 24 hours postinjection, toxicity was tested
and survivors were mated.
Duration of treatment / exposure:
72 hours
Frequency of treatment:
1 time
Post exposure period:
no data
Doses / concentrations
Remarks:
Doses / Concentrations:
2000 mg/kg
Basis:
nominal in diet
Control animals:
yes, concurrent vehicle
Positive control(s):
none

Examinations

Tissues and cell types examined:
postmeiotic and meiotic germ cells
Details of tissue and slide preparation:
For the SLRL test, each male was mated individually to three Basc virgin females, then transferred to fresh Basc virgin females every 2 to 3 days to
make a total of three broods. To reduce the probability of recovering multiple lethals from one male, no more than 100 F1 females were mated over
the three broods from any P1 male. F2 cultures were scored as presumptive lethals if the number of wild-type males was 0, 1, or < 5% of the number
of Basc males. All putative lethals were confirmed through an additional generation.
Evaluation criteria:
Criteria for evaluating results:    
mutation frequency > 0.15 % (P < 0.05): positive   
mutation frequency > 0.10 % (P < 0.01): positive   
mutation frequency 0.10-0.15 % (P 0.01-0.05): equivocal   
other: negative
Statistics:
For the SLRL assay, a minimum of 5000 chromosomes was scored from each of the treated and concurrent control groups unless the mutant
frequency exceeded 1%.
The treated and control data were compared using a normal approximation to the binomial distribution. In addition, the trated data were compared to the historial control.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Remarks:
no mutagenic effects were observed
Toxicity:
no effects
Remarks:
no toxic effects were observed
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
not examined
Additional information on results:
MORTALITY: 
- feeding: 15 %
- injection: 47 %
PERCENT STERILITY:
- feeding, injection: 0 %
PERCENT LETHALS:
- feeding:   0.11 %; control: 0.18 %
- injection: 0.22 %; control: 0.17 %

RESULT:  - feeding, injection: negative

Any other information on results incl. tables

no remarks

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
In this Sex Linked Recessive Lethal (SLRL) test with Drosophila melanogaster no indication of a mutagenic effect was observed.
Executive summary:

In this Sex Recessive Lethal (SLRL) test with Drosophila melanogaster, fruit flies were fed a diet containing 2000 mg/kg isophorone. After 72 hrs of exposure, surviving males were mated. As feeding exposure was found to be non-mutagenic, 2 -3 day old males were injected with a 0.7 % NaCl solution containing 12,500 mg/l isophorone. 24 hrs post injection, males were mated. Again there was no indication of a mutagenic effect. Concurrent control males were treated with ethanol used to dissolve the test chemical.