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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
three-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1977-05-22 to 1979-07-30
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Non-guideline study, pre-GLP 1979 study, limitations in design and/or reporting but otherwise adequate for assessment
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
Deviations:
yes
Remarks:
There were only 2 dietary concentrations tested
GLP compliance:
no
Remarks:
study report is dated July 1979, pre-GLP
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Source: MC/B, 2909 Highland Ave., Norwood, Ohio 45212
- Catalogue number: TX310
- Analysis: Performed with a UC-W98 column. Retention time was 1.9 minutes. Trace impurities noted at approximately 1.5 minutes and 2.1 minutes.
- Purity appeared to be 98 to 99%, consistent with the MC/B assay of 99.79%.
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: MC/B (2909 Highland Avenue, Norwood, Ohio 45212); Catalog No. TX 310
- Expiration date of the lot/batch: Not specified
- Purity test date: Analysis of DCPD was performed with a UC-W98 column post receipt on August 18, 1976. (Purity: 98 to 99%)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Closed container in the freezer
- Stability under test conditions: Stability analysis revealed that in the closed containers, the concentration dropped 27.6% for the 80 ppm level and 30.8% for the 750 ppm level over a 10-day period.
- Solubility and stability of the test substance in the solvent/vehicle: Because of poor water solubility, DCPD was prepared for administration to animals by dissolving it in corn oil (Mazola).

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: waxy solid converted to an easily measured liquid by slight warming

FORM AS APPLIED IN THE TEST (if different from that of starting material) : waxy solid converted to an easily measured liqud by slight warming

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on species / strain selection:
CRL:COB (SD) BR
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc. (Portage, Michigan, USA)
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Age at study initiation: (P) - Weanling albino rats
- Weight at study initiation: Not specified
- Fasting period before study: Not specified
- Housing: housed individually (except when mating) in shoe box cages on AB-SORB-DRI bedding
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet (e.g. ad libitum): Purina Laboratory Chow meal provided ad libitum
- Water (e.g. ad libitum): water provided ad libitum
- Acclimation period: Acclimated to laboratory conditions for 11 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Not specified
- Humidity (%): Not specified
- Air changes (per hr): Not specified
- Photoperiod (hrs dark / hrs light): Not specified

IN-LIFE DATES: From: 1977-05-22 To: Not specified

Administration / exposure

Route of administration:
oral: feed
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): Fresh diets were prepared weekly
- Mixing appropriate amounts with (Type of food): Diets prepared by adding the appropriate quantity of DCPD, dissolved in 300 mL of corn oil, to 10 Kg of Purina Laboratory Chow meal, and mixing for at least 15 minutes in a twin shell blender. Control diet was mixed with corn oil in the same fashion.
- Storage temperature of food: Stored at ambient conditions

VEHICLE
- Justification for use and choice of vehicle (if other than water): Because of poor water solubility, DCPD was prepared for administration to animals by dissolving it in corn oil (Mazola). The handling of DCPD itself was facilitated by slight warming, which converted the waxy solid to an easily measured liquid.
- Concentration in vehicle: at concentrations appropriate to the various studies
Details on mating procedure:
- M/F ratio per cage: Each male caged with two females of its dose group
- Length of cohabitation: 2 weeks
- Proof of pregnancy: Not specified
- Further matings after two unsuccessful attempts: Not specified
- After successful mating each pregnant female was caged (how): rats were returned to their respective cages and the females were allowed to litter
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Because of the possible loss from the diet through volatility of DCPD, samples of each week's dietary batch were analyzed by the LBI Chemistry Department. The analytical method employed gas-liquid chromatography and was supplied by the sponsor and developed at LBI.
Duration of treatment / exposure:
For 7 weeks prior to mating of the F0 parents through to study termination.
Frequency of treatment:
Continuous in diet
Details on study schedule:
- F0 rats were mated seven weeks after initiation of treated diet. One week after weaning the first litters (F1a pups), the F0 parents were remated, each male with a different pair of females from that of the first mating. One week after weaning the second litters (F1b pups), parent F0 rats were killed.
- Selected F1b pups were designated F1 parents and were approx. 100 days old when mated to produce the F2a litters and subsequently the F2b litters. Selected F2b pups were designated F2 parents and similarly used to produce the F3 a and b litters.
Doses / concentrationsopen allclose all
Dose / conc.:
0 ppm
Remarks:
Basis: nominal in diet
Group 1 (Control)
Dose / conc.:
80 ppm
Remarks:
Basis: nominal in diet
69.3 ppm (analytical concentration)
Group 2
Dose / conc.:
750 ppm
Remarks:
Basis: nominal in diet
693 ppm (analytical concentration)
Group 3
No. of animals per sex per dose:
10 males, 20 females
Control animals:
yes, plain diet
Details on study design:
- Dose selection rationale: A clear rationale for selection of the doses that were used in the study is not provided in the study report. However, in a rat teratology study with DCPD conducted by the same laboratory in 1977 (LBI Project number 10734-05), the study report mentions that the dose levels used in the study were approved by Dr. E. Ross Hart of LBI based on previous studies.
- Rationale for animal assignment (if not random): Rats were assigned randomly to the study groups

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily observations were made of parent rats for mortality and general condition

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: At 4 and at 8-9 weeks, and shortly before each mating, parent rats were weighed

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes; At 4 and at 8-9 weeks, and shortly before each mating, the food consumption of parent rats was estimated
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
Oestrous cyclicity (parental animals):
No
Sperm parameters (parental animals):
No
Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- At Day 4 each litter was reduced to eight total pups, four per sex if possible

PARAMETERS EXAMINED
The following parameters were examined in [F1 / F2 / F3] offspring:
- Gross abnormalities of pups
- Numbers of live and dead pups, and their mean body weight by sex at birth
- Number per sex Day 4 of lactation
- Number per sex and body weights Day 21 of lactation (weaning)

GROSS EXAMINATION OF DEAD PUPS: Yes; At weaning, gross necropsies were performed on approximately one-third of the first litters from all three generations, and on one-third of the F3b litters.

ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY: No

ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY: No
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals (A gross necropsy was performed on each Parent F0 animal one week after weaning the second litters (F1b pups).
- Maternal animals: All surviving animals (A gross necropsy was performed on each Parent F0 animal one week after weaning the second litters (F1b pups).

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
No data
Postmortem examinations (offspring):
At weaning, gross necropsies were performed on approximately one-third of the first litters from all three generations, and on one-third of the F3b litters.
Statistics:
Student's t-test; Chi-square test
Reproductive indices:
Male and female fertility; gestation index.
Offspring viability indices:
Newborn viability; pup viability (Days 0-4); lactation viability (days 4-21); sex ratio Day 0; Live pups per litter

Results and discussion

Results: P0 (first parental animals)

General toxicity (P0)

Clinical signs:
no effects observed
Description (incidence and severity):
One F0 female (No. 5196, 80 ppm) was found dead at Week 28, but all other F0 rats survived their portion of the study in generally good condition. Data for compound-treated groups were entirely comparable to control figures at each interval.
Mortality:
mortality observed, non-treatment-related
Description (incidence):
One F0 female (No. 5196, 80 ppm) was found dead at Week 28, but all other F0 rats survived their portion of the study in generally good condition. Data for compound-treated groups were entirely comparable to control figures at each interval.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
F0 parents - Data for compound-treated groups were entirely comparable to control figures at each interval.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
F0 - Data for compound-treated groups were entirely comparable to control figures at each interval.
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
F0 - Necropsy findings of F0 parents indicated no dose-related changes.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
no effects observed
Description (incidence and severity):
Reproductive and litter indices were unaffected by exposure to DCPD (please see Tables 3 and 4) below.

Effect levels (P0)

Key result
Dose descriptor:
NOAEL
Remarks:
F0 Parents
Effect level:
750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Systemic Toxicity

Target system / organ toxicity (P0)

Key result
Critical effects observed:
no

Results: P1 (second parental generation)

General toxicity (P1)

Clinical signs:
no effects observed
Description (incidence and severity):
F1b Parents - No clinical signs reported.
Mortality:
no mortality observed
Description (incidence):
F1b Parents - No mortality observed
Body weight and weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
F1b Parents - At all intervals, rats in the compound-treated groups weighed as much as or more than the controls, except for the 80-ppm females at 20 weeks (just prior to the second mating). In this instance, the slightly lower mean body weight was not statistically significant.

F2b Parents - No meaningful differences between groups at the various intervals were seen with respect to body weight.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
F1b Parents - food consumption means were comparable among the groups, except that in both males and females of the 750-ppm group, the reductions at 20 weeks in food intake were statistically significant (p<0.05, Student's t-test).

F2b Parents - No meaningful differences between groups at the various intervals were seen with respect to food consumption.
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
F1b Parents - At necropsy, no gross lesions were found in the F1b parent rats.

F2b Parents - Necropsy findings of the F2b parents were unexceptional.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
not examined

Reproductive function / performance (P1)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
effects observed, non-treatment-related
Description (incidence and severity):
F1b Parents - In the first mating to produce the F2a generation, except for reduced female fertility in the 750-ppm group, litter data in all groups were comparable.
However, the 70% figure (Table 5) for the F2a was not statistically significantly different (Chisquare test) from the control index (95%). In addition, it may be noted that male No. 7349 in the 750-ppm group failed to sire a litter in either mating, and could thus be responsible for the lack of litters from two of six non-productive females at the first mating. It was therefore concluded that the apparently lowered fertility of the high-dose females at the first mating was not related to compound administration.

In the second mating to produce the F2b generation, fertility in the 750-ppm females was reduced. However, the 85% figure (Table 6) for the F2b's was not statistically significantly different (Chisquare test) from the control index (95%). In addition, it may be noted that male No. 7349 in the 750-ppm group failed to sire a litter in either mating, and could thus be responsible for the lack of litters from two of three non-productive females at the second mating. It was therefore concluded that the apparently lowered fertility of the high-dose females at the second mating is not related to compound administration.

F2b Parents - Although female fertility was only 80% and 83% in the DCPD-treated groups, control fertility was worse, only 65%. There was nothing in these records to suggest a compound-related effect.

Effect levels (P1)

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
F1b Parents
Effect level:
80 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Systemic Toxicity
Key result
Dose descriptor:
NOAEL
Remarks:
F2b Parents
Effect level:
750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Systemic toxicity

Target system / organ toxicity (P1)

Key result
Critical effects observed:
no

Results: F1 generation

General toxicity (F1)

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
There was nothing in the data to distinguish DCPD-treated groups (F1a) from control rats. Observations of the pups did not indicate anything of importance in the three groups. One F1a pup in a 80-ppm litter had an opaque left eye, and one F1a pup in a 750-ppm litter had a crooked tail. Such isolated findings were not considered to be meaningful.

All F1b generation groups were comparable to one another with respect to both litter data and pup observations. A single instance of a pup in the 80-ppm group with an abnormality (a deformed hind foot) was not considered to be meaningful.
Mortality / viability:
mortality observed, non-treatment-related
Description (incidence and severity):
No mortality observed in F1a offspring.

F1b Offspring - Group 1 (Control (0 ppm)): 3 males and 3 females were found dead on lactation days 0-6; Group 2 (80 ppm): 3 males and 3 females were found dead on lactation days 0-4; Group 3 (750 ppm): 2 males were found dead on lacation days 4-11; and one pup was found dead, partially cannabalized on lacation day 0. Please see table Table 7 (pup observations (F1b)) of the attached study report for further details.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
F1a Offspring - No compound-related findings were reported

F1b Offspring - No compound-related findings were reported
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
F1a Offspring - No compound-related findings were reported

F1b Offspring - No compound-related findings were reported
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
F1a Offspring - No compound-related findings were reported

F1b Offspring - No compound-related findings were reported
Histopathological findings:
not examined
Other effects:
not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):
not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not examined

Details on results (F1)

F1a Offspring - All groups were comparable to one another with respect to both litter data and pup observations.

F1b Offspring - All groups were comparable to one another with respect to both litter data and pup observations.

Effect levels (F1)

open allclose all
Key result
Dose descriptor:
NOAEL
Generation:
F1a
Effect level:
750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity
Key result
Dose descriptor:
NOAEL
Generation:
F1b
Effect level:
750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity

Target system / organ toxicity (F1)

Key result
Critical effects observed:
no

Results: F2 generation

General toxicity (F2)

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
F2a Offspring - No general findings of significance were recorded, but one male pup in the 80-ppm group was found to have had hydrocephalus.
F2b Offspring - General pup observations were unexceptional.

F3a Offspring - Pup general observations showed nothing to indicate compound-related effects
F3b Offspring - Pup general observations showed nothing to indicate compound-related effects
Mortality / viability:
mortality observed, non-treatment-related
Description (incidence and severity):
F2a Offspring - Group 1 (Control (0 ppm)): 1 male was found dead on lactation day 4; Group 2 (80 ppm): 2 females, 1 found dead and 1 in moribund condition (killed)) were found on lactation day 4 while 1 male was found dead on lacation day 20; Group 3 (750 ppm): 1 female was found dead on lactation day 4. Please see Table 12 (pup observations F2a in the attached study report for further details).

F2b Offspring - Group 1 (Control (0 ppm)): 1 male was found dead on lactation day 4; Group 2 (80 ppm): 2 males, 1 found dead on lactation day 2 and 1 found dead on lactation day 4; Group 3 (750 ppm): 1 male was found dead on lactation day 4. Please see Table 15 (pup observations F2b in the attached study report for further details).

F3a Offspring - Group 1 (Control (0 ppm)): Three males and 2 females found dead while 1 pup was cannibalized on lactation day 11. One male was found dead on lactation day 12; Group 2 (80 ppm): No mortality; Group 3 (750 ppm): 1 female found dead on lactation day 3 and 1 male found dead on lactation day 4.

F3b Offspring - Group 1 (Control (0 ppm)): 1 female was found dead and 3 females were cannabilized on lactation day 4; Group 2 (80 ppm): No mortality; Group 3 (750 ppm): 3 females were cannibalized on lactation day 4.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
F2a Offspring - No effect on body weights of F2a offspring was reported.
F2b Offspring - No effect on body weights of F2b offspring was reported.

F3a Offspring - No effect on body weights of F3a offspring was reported.
F3b Offspring - A slight reduction in mean pup weight at weaning (compared to controls) was noted in each compound-treated group, that for the high dose female pups being statistically significant (p<0.05; Student's t-test). The low-dose female pup weight, while numerically the same as that of the 750-ppm weanlings, was not statistically significant. Since mean weanling pup weights in the other generations were not appreciably different among the groups involved, the study authors felt that the F3b differences were fortuitous.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
F2a Offspring - No effect on food consumption of F2a offspring was reported.
F2b Offspring - No effect on food consumption of F2b offspring was reported.

F3a Offspring - No effect on food consumption of F3a offspring was reported.
F3b Offspring - No effect on food consumption of F3b offspring was reported.
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
F2a Offspring - no necropsy findings of significance were recorded, but one male pup in he 80-ppm group was found to have had hydrocephalus.
F2b Offspring - no necropsy findings of significance were reported.

F3a Offspring - Gross necropsy did not reveal any remarkable findings.
F3b Offspring - Gross necropsy did not reveal any remarkable findings.
Histopathological findings:
not examined
Other effects:
not examined

Developmental neurotoxicity (F2)

Behaviour (functional findings):
not examined

Developmental immunotoxicity (F2)

Developmental immunotoxicity:
not examined

Details on results (F2)

F2a Offspring - Except for reduced female fertility in the 750-ppm group (discussed earlier), litter data in all groups were comparable.

F2b Offspring - Except for reduced female fertility in the 750-ppm group (discussed earlier), litter data in all groups were comparable.

F3a Offspring - Litter parameters were not affected by treatment. The study authors concluded that there was nothing to suggest a compound-related effect, although female fertilitywas only 80% and 83% in the DCPD-treated groups, control fertility was worse, only 65%.

F3b Offspring - Litter data in all groups was generally comparable with respect to the various indices. Femalefertility percentages were 85, 80 and 83 for the controls, 80- and 750-ppm groups, respectively. The differences were not considered to be meaningful by the study authors.

Effect levels (F2)

open allclose all
Key result
Dose descriptor:
NOAEL
Generation:
F2a
Effect level:
> 80 - < 750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity
Key result
Dose descriptor:
NOAEL
Generation:
F2b
Effect level:
> 80 - < 750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity
Key result
Dose descriptor:
NOAEL
Generation:
other: F3a
Effect level:
750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity
Key result
Dose descriptor:
NOAEL
Generation:
other: F3b
Effect level:
> 80 - < 750 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Reproductive Toxicity

Target system / organ toxicity (F2)

Key result
Critical effects observed:
no

Overall reproductive toxicity

Key result
Reproductive effects observed:
yes
Lowest effective dose / conc.:
750 ppm (nominal)
Treatment related:
yes
Relation to other toxic effects:
not specified
Dose response relationship:
yes
Relevant for humans:
not specified

Any other information on results incl. tables

Diet Concentrations

Overall, the  results of the DCPD weekly feed analyse showed  a  69.3 ppm  (87%)  average value for the 80-ppm diet level,  and 693 ppm  (92%)  for the  750-ppm diet level.  Considering the volatility of DCPD,  these results are thought  to indicate reasonable achievement of the intended dietary concentrations.

Table 2. Mean Food Consumption (G) In F1b Rats

Dose (ppm)

Sex

 

Week

4

9

11

20

0

Male

Mean

25

26

26

32

SD

3.8

3.0

3.7

5.7

SE

1.2

1.1

1.4

1.8

N

10

8

7

10

 

80

Male

Mean

26

28

27

30

SD

3.2

1.3

1.7

3.2

SE

1.3

0.46

0.55

1.0

N

6

8

10

10

 

750

Male

Mean

25

25

25

25*

SD

1.9

1.9

0.58

3.2

SE

0.67

0.63

0.20

1.0

N

8

9

8

10

 

0

Female

Mean

22

22

23

29

SD

4.6

4.2

6.0

4.0

SE

1.1

0.89

1.4

1.0

N

17

18

18

16

 

80

Female

Mean

25

25

26

33

SD

2.6

3.6

4.4

6.1

SE

0.91

0.96

1.2

1.4

N

8

14

13

18

 

750

Female

Mean

21

22

21

24*

SD

4.9

4.3

5.0

5.9

SE

1.3

1.0

1.2

1.6

N

15

17

19

14

*p<0.05 as compared to controls: Student's t-test

Table 3. Summary of First Generation – First Mating (F1a)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

10/10

100

10/10

100

9/10

90

 

Female Fertility

(females producing litter/ mated)

19/20

95

18/20

90

16/20

80

 

Gestation

(females live litter/pregnant)

19/19

100

18/18

100

16/16

100

 

Newborn viability

(live pups/total pups)

209/211

99

210/212

99

198/200

99

 

Pup Viability

(pups Day 4/pups Day 0)

205/209

98

207/210

99

194/198

98

 

Lactation

(pups Day 21/pups Day 4)a

140/140

100

140/140

100

128/128

100

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

7 ± 0.66

7 ± 0.68

7 ± 0.60

Day 0 females

7 ± 0.75

6 ± 0.59

6 ± 0.72

Day 21 males

52 ± 5.4

50 ± 5.6

48 ± 5.1

Day 21 females

49 ± 4.6

46 ± 5.1

46 ± 4.7

Sex Ratio offspring (M/F Day 0)

110/101

111/101

94/106

Live pups per litter (Mean ± SD)

11 ± 3.7

12 ± 2.8

12 ± 2.3

aAfter Litters Reduced

Table 4. Summary of F0 Generation – Second Mating (F1b)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

10/10

100

10/10

100

10/10

100

 

Female Fertility

(females producing litter/ mated)

18/20

90

18/20

90

19/20

95

 

Gestation

(females live litter/pregnant)

18/18

100

18/18

100

19/19

100

 

Newborn viability

(live pups/total pups)

199/201

99

196/202

97

229/231

99

 

Pup Viability

(pups Day 4/pups Day 0)

193/199

97

187/196

95

216/229

94

 

Lactation

(pups Day 21/pups Day 4)a

128/132

97

128/132

97

139/145

96

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

6 ± 1.1

5 ± 1.6

6 ± 0.61

Day 0 females

6 ± 1.1

5 ± 1.6

6 ± 0.61

Day 21 males

46 ± 7.8

47 ± 8.8

42 ± 6.8

Day 21 females

44 ± 6.9

44 ± 8.2

40 ± 5.7

Sex Ratio offspring (M/F Day 0)

100/101

94/108

108/123

Live pups per litter (Mean ± SD)

11 ± 3.5

11 ± 3.7

12 ± 3.2

aAfter Litters Reduced

Table 5. Summary of F1b Generation – First Mating (F2a)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

10/10

100

10/10

100

9/10

90

 

Female Fertility

(females producing litter/ mated)

19/20

95

18/20

90

14/20

70

 

Gestation

(females live litter/pregnant)

19/19

100

18/18

100

14/14

100

 

Newborn viability

(live pups/total pups)

241/242

100

209/216

97

162/162

100

 

Pup Viability

(pups Day 4/pups Day 0)

237/241

98

196/209

94

159/162

98

 

Lactation

(pups Day 21/pups Day 4)a

147/150

98

135/139

97

107/109

98

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

6 ± 0.90

6 ± 0.84

6 ± 0.83

Day 0 females

6 ± 0.79

6 ± 0.92

6 ± 0.95

Day 21 males

44 ± 5.9

46 ± 6.4

44 ± 5.5

Day 21 females

41 ± 5.3

43 ± 6.6

42 ± 5.3

Sex Ratio offspring (M/F Day 0)

111/131b

94/122b

84/78b

Live pups per litter (Mean ± SD)

13 ± 2.6

12 ± 2.7

12 ± 2.7

aAfter Litters Reduced

bSome pups mis-sexed

Table 6. Summary of F1b Generation – Second Mating (F2b)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

10/10

100

10/10

100

9/10

90

 

Female Fertility

(females producing litter/ mated)

19/20

95

19/20

95

17/20

85

 

Gestation

(females live litter/pregnant)

19/19

100

19/19

100

17/17

100

 

Newborn viability

(live pups/total pups)

263/266

99

286/287

100

230/235

98

 

Pup Viability

(pups Day 4/pups Day 0)

250/263

95

280/286

98

214/230

93

 

Lactation

(pups Day 21/pups Day 4)a

149/151

99

149/152

98

127/128

99

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

6 ± 0.84

6 ± 0.63

6 ± 0.54

Day 0 females

6 ± 0.75

6 ± 0.52

6 ± 0.66

Day 21 males

45 ± 6.8

48 ± 7.2

51 ± 6.6

Day 21 females

43 ± 7.4

46 ± 6.6

48 ± 6.6

Sex Ratio offspring (M/F Day 0)

121/145

146/141

119/116

Live pups per litter (Mean ± SD)

14 ± 2.5

15 ± 1.6

14 ± 1.4

aAfter Litters Reduced

Table 7. Summary of F2b Generation – First Mating (F3a)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

9/10

90

10/10

100

8/9

89

 

Female Fertility

(females producing litter/ mated)

13/20

65

16/20

80

15/18

83

 

Gestation

(females live litter/pregnant)

13/13

100

16/16

100

15/15

100

 

Newborn viability

(live pups/total pups)

162/163

99

195/196

99

204/206

99

 

Pup Viability

(pups Day 4/pups Day 0)

156/162

96

187/195

96

201/204

99

 

Lactation

(pups Day 21/pups Day 4)a

92/100

92

118/118

100

117/120

98

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

6 ± 0.77

6 ± 1.3

7 ± 0.82

Day 0 females

7 ± 0.80

5 ± 1.2

6 ± 0.80

Day 21 males

46 ± 5.8

46 ± 4.7

48 ± 6.1

Day 21 females

45 ± 7.6

42 ± 4.2

45 ± 5.7

Sex Ratio offspring (M/F Day 0)

81/82

103/92

108/98

Live pups per litter (Mean ± SD)

12 ± 3.3

12 ± 3.9

14 ± 2.0

aAfter Litters Reduced

Table 8. Summary of F2b Generation – First Mating (F3b)

Indices

Dose (ppm)

0

80

750

Ratio

Percent

Ratio

Percent

Ratio

Percent

Male Fertility

(males producing litter/ mated)

9/10

90

10/10

100

9/9

100

 

Female Fertility

(females producing litter/ mated)

17/20

85

16/20

80

15/18

83

 

Gestation

(females live litter/pregnant)

17/17

100

16/16

100

15/15

100

 

Newborn viability

(live pups/total pups)

211/215

98

206/213

97

188/191

98

 

Pup Viability

(pups Day 4/pups Day 0)

207/211

98

206/206

100

185/188

98

 

Lactation

(pups Day 21/pups Day 4)a

134/135

99

127/128

99

114/117

97

 

Pup Weight in Grams (Mean ± SD)

Day 0 males

6 ± 0.79

7 ± 0.98

7 ± 0.83

Day 0 females

6 ± 0.64

6 ± 0.87

6 ± 0.83

Day 21 males

49 ± 10

44 ± 11

43 ± 11

Day 21 females

48 ± 9.3

41 ± 12

41 ± 9.5*

Sex Ratio offspring (M/F Day 0)

93/122

107/106

93/98

Live pups per litter (Mean ± SD)

12 ± 2.7

13 ± 2.5

13 ± 2.8

aAfter Litters Reduced

*p<0.05 compared to control: Student’s t-test.

Applicant's summary and conclusion

Conclusions:
The authors of the study considered that dietary administration of DCPD at 80 and 750 ppm to three successive generations of rats had no deleterious effects on reproductive performance or the general condition of the animals. However, DCPD was not devoid of reproductive or systemic effects at the 750 ppm dietary level, as previously described.

Thus, the NOAEL in this study is considered to be between 80 - 750 ppm (69 - 693 ppm actual concentration).

Executive summary:

This three generation reproduction non-GLP study in rats using dicyclopentadiene was conducted in 1979, prior to the adoption of the OECD test guidelines for reproductive and developmental toxicity. However the methods used and overall quality of the study were considered similar to OECD 416 and the study was considered adequate for assessment.

 

F0 rats were mated seven weeks after initiation of treated diet. Selected F1b pups were designated F1 parents and were approx. 100 days old when mated to produce the F2a litters and subsequently the F2b litters. Selected F2b pups were designated F2 parents and similarly used to produce the F3 a and b litters. Animals were exposed to nominal dietary concentrations of 0, 80, 750 ppm DCPD.

 

The authors of the study considered that dietary administration of DCPD at nominal concentrations of 80 and 750 ppm to three successive generations of male and female albino rats had no deleterious effects on reproductive performance or the general condition of the animals, in comparison to performance of control rats maintained concurrently. However, DCPD was not devoid of reproductive or systemic effects at the 750 ppm dietary level. Mean food consumption at 20 weeks in the F1B parents was reduced in both sexes in a treatment-related manner, with statistical significance at the 750 ppm level. At 750 ppm, female fertility was reduced in the F2A and F2B generations, however, the differences from control were not statistically significant, and this may have been due to one male in the 750 ppm group that failed to sire litters in either mating. A treatment- related reduction in mean pup weight on PND 21 was noted in the F3B generation, with mean m/f pup weights of 49/48, 44/41, and 43/41* grams in the control, 80 and 750 ppm groups, respectively.

 

Thus, the NOAEL in this study is considered to be between 80 - 750 ppm (69 - 693 ppm actual concentration).