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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: other: mutation and chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Reliable study performed to National Toxicology Program protocols.

Data source

Referenceopen allclose all

Reference Type:
other: NTP website
Title:
Unnamed
Reference Type:
publication
Title:
Unnamed
Year:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 477 (Genetic Toxicology: Sex-linked Recessive Lethal Test in Drosophila melanogaster)
Deviations:
no
Principles of method if other than guideline:
For the reciprocal translocation studies, Canton-S males were mated en masse to marker (bw;st or bw;e) females. The females were transferred to fresh medium every 3 to 4 days for a period of at least 2 weeks. The results of the SLRL test were used to determine the germ cell stages most likely to be affected by the test chemical. F1 heterozygous males were backcrossed individually to bw;st females and the F2 progeny were screened for pseudolinkage, resulting from the induction of a translocation in a germ cell of the P1 male.
GLP compliance:
not specified
Type of assay:
other: Drosophila SLRL and reciprocal translocation tests

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Ferrocene
- Substance type: technical product
- Physical state: solid
- Analytical purity: >95%
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data

Test animals

Species:
Drosophila melanogaster
Strain:
other: Canton-S
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: University of Wisconsin
- Age at study initiation: 24 h for feeding test; 2-4 days for injection tests
- Weight at study initiation: not applicable
- Assigned to test groups randomly: not applicable
- Fasting period before study: no
- Housing: feeding vials
- Diet (e.g. ad libitum): "feeding solution" in 5% sucrose
- Water (e.g. ad libitum): not applicable


Administration / exposure

Route of administration:
other: in feeding solution or by injection
Vehicle:
- Vehicle(s)/solvent(s) used: 10% ethanol (solvent); 0.7% NaCl (vehicle for injection)
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: no data

DIET PREPARATION
- Rate of preparation of diet (frequency): every 24 h
Duration of treatment / exposure:
72 h (feeding test)
Single dose (injection)
Frequency of treatment:
single injection or a 72 h exposure (feeding)
Post exposure period:
The males and females were mated immediately after exposure (feeding; SLRL) or held for 24 h before mating (injection; SLRL and reciprocal translocation)
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 25, 50, or 100 ppm (feeding); 100 ppm (injection)
Basis:
nominal conc.
No. of animals per sex per dose:
no data on exposed males; a total of 120 F1 females were mated with their F1 siblings (SLRL)
Control animals:
yes, concurrent no treatment
Positive control(s):
N-dimethylnitrosamine; beta-propiolactone
- Justification for choice of positive control(s): no data
- Route of administration: feeding and injection
- Doses / concentrations: no data

Examinations

Tissues and cell types examined:
SRSL test: Vials were examined after 17 days for the number of wild-type and Basc males or 20 Basc/+ females.

Reciprocal translocation test: Canton-S males were mated en masse to marker (bw;st or bw;e) females. The females were transferred to fresh medium every 3 to 4 days for a period at least 2 weeks to produce a total of 3 broods. F1 heterozygous males were backcrossed individually to bw;st females and the F2 progeny were screened for the following translocations: T(2;3)s, T(Y;2)s and T(Y;2;3)s.


Details of tissue and slide preparation:
not applicable
Evaluation criteria:
Presumptive lethal mutations were identified as vials containing fewer than 5% of the expected number of wild-type males after 17 days and at least 20 Basc males or 20 Basc/+ females appeared; or at least 17 Basc males or 17 Basc/+ females appeared and no wild-type males.

A culture was judged to contain a translocation when no recombinant and 20 nonrecombinant offspring were observed.
Statistics:
SRSL data were analysed by the normal test, and the translocation data according to the conditional binomial.

A test was regarded as positive if the P value was < 0.01 or between 0.04 and 0.01 and the current control frequency was > 0.055.

Results and discussion

Test resultsopen allclose all
Sex:
male
Genotoxicity:
positive
Remarks:
for SLRL mutations after injection
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Sex:
male
Genotoxicity:
negative
Remarks:
for SLRL mutations after exposure by feeding
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not specified
Positive controls validity:
valid
Sex:
male
Genotoxicity:
positive
Remarks:
for reciprocal translocations after injection
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
not applicable

Any other information on results incl. tables

Drosophila sex-linked recessive lethals results

Exposure route

Dose (ppm)

% Mortality

% Sterility

No. of Lethals/No of X chromosomes tested

Total Lethals/Total Tests

Mating 1

Mating 2

Mating 3

Adult feeding for three days

100

18

34

0/11

0/489

0/443

0/943 (0.00%)

0

 

 

0/1083

2/982

0/1022

2/3087 (0.06%)

50

0

24

0/71

0/649

1/609

1/1329 (0.08%)

0

 

 

2/1152

1/1152

0/1152

3/3456 (0.09%)

25

0

8

4/1502

0/1240

0/1108

4/3850 (0.10%)

0

 

 

0/1362

1/1409

0/1278

1/4049 (0.02%)

P=0.272

Adult injection

100

10

4

8/2846

3/2499

4/2272

15/7617 (0.20%)

0

 

 

0/3379

0/3390

2/3315

2/10084 (0.02%)

P=0.000

                 

 

 Drosophila reciprocal translocation results

 

Exposure route

Dose (ppm)

Solvent

No. RTs/No tests per sperm batch

(days of storage in female before testing)

Total no. translocations

Translocation frequency (%)

0-3

3-7

7-10

10-14

14-17

17-20

Adult injection

100

10-40% ethanol

0/1389

2/1390

2/1392

0/1272

0/604

0/244

2/6291

0.03

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: positive for SLRLs and translocations after injection. Negative for SLRLs after feeding
In a reliable NTP study, ferrocene induced both sex-linked recessive lethal (SLRL) mutations and reciprocal translocations in male Drosophila when exposed at up to 100 ppm by a single injection. However, no SLRLs were observed when similar doses were given by feeding over a 3-day period.
Executive summary:

In a reliable NTP study, ferrocene was assessed for its ability to induce both sex-linked recessive lethal (SLRL) mutations (using a protocol similar to OECD guideline 477) and also reciprocal translocations (for which no guideline is currently available) in Drosophila.

Males were exposed to 100 ppm either by feeding the test substance for three days (SLRL assay) or by a single injection (SLRL and reciprocal translocation assays). For SLRLs the males were then individually mated with Basc virgin females to produce three broods. The F1 generation females were then mated with their male siblings. Vials were examined after 17 days for the number of wild-type and Basc males or 20 Basc/+ females. In the reciprocal translocation assay males were crossed with bw;e females, and the females transferred to fresh food every 3 -4 days to study the effects of sperm storage. F1 heterozygous males were backcrossed individually to bw;e females and the F2 progeny were screened for translocations in the Y chromosome and chromosomes 2 and 3.

Ferrocene was positive in the SLRL test only after a single injection, increasing the incidence of mutations by 0.2%; no response was detected after feeding, in which the dose was given over a 72 -h period. A positive result for chromosome breakage after injection was also seen in the assay for reciprocal translocation, where the incidence of translocations was increased by 0.03%.

Ferrocene gave a positive response after a single injection in both a SLRL test and an assay for reciprocal translocation. The same dose given in the feed over a 72-h period showed no response in the SLRL assay.