Registration Dossier

Administrative data

Endpoint:
toxicity to reproduction: other studies
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Although not a guideline study, study followed acceptable scientific principles for the time. Study included control, and positive control animals.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1961
Report Date:
1961

Materials and methods

Principles of method if other than guideline:
Test article was incorporated into the diet at three levels and was fed to known fertile female rats 7 days prior to mating, during mating and gestation, and until day 4 after parturituion. Contol animals received plain diet; positive control animals were also used (N,N'-diphenyl-p-phenylenediamine. Endpoints measured were gestation length, number of pups in litter, size of pups, number of live births/stillborn pups.
GLP compliance:
no
Type of method:
in vivo

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Antioxidant 702, Ethyl Corporation, 4,4’-methylenebis (2,6-di-tert-butylphenol). Light crystalline solid, density of 0.990 at 68 degrees F, mp of 155 degrees C. Soluble 33% in toluene, 6% in alcohol, and practically insoluble in water.):
- Physical state: Light crystalline solid, density of 0.990 at 68 degrees F, mp of 155 degrees C. Soluble 33% in toluene, 6% in alcohol, and practically insoluble in water.):
:

Test animals

Species:
rat
Strain:
other: CFN
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Carworth Farms
- Age at study initiation: Males and Females had produced at least one litter previously
- Housing: 5 females per group; one male added to the 5 females for breeding
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

Administration / exposure

Route of administration:
oral: feed
Vehicle:
other: Alphacel non-nutritive cellulose
Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): once at study initiation
- Mixing appropriate amounts with (Type of food): Purina Laboratory Chow meal
- Storage temperature of food: stored in crocks with lids

VEHICLE
- Justification for use and choice of vehicle (if other than water): Alphacel used to dilute powdered test articles to equal volumes

POSITIVE CONTROL: technical grade N.,N’-diphenyl-p-phenylenediamine (DPPD), obtained from Distillation Products Industries. Purity 95%, black crystalline solid. Concentration used in study 1.25% of diet.
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
7 days prior to mating, through gestation, and to day 4 after delivery
Frequency of treatment:
daily in feed
Duration of test:
7 days prior to mating, through mating (12 days), gestation, and to day 4 after delivery
No. of animals per sex per dose:
5 females, 1 male per dose or treatment. Control diet was Purina Chow. Treatments were positive control (DPPD) or test article (702). One dose level for DPPD (1.25% of diet) and three dose levels of 702 (1.25%, 0.50%, and 0.125% of diet).
Details on study design:
Mating: after females were on respective diets for 7 days, a male of known fertility was introduced into each cage of 5 females. Males remained with the females for 12 days. Females remained on the diets throughout the experiment; males were maintained on diet only during breeding.

Signs of insemination: detection of copulation plug was date beginning gestation length. Pregnancy was established by relatively large increase in body weight.

Measurements: on day of deliver, size and weight of litter, and number of live offspring recorded. Number of survivors after 4 days were also recorded.

Results and discussion

Effect levels

Dose descriptor:
NOEC
Effect level:
1.25 other: percent in diet
Based on:
act. ingr.
Sex:
female
Basis for effect level:
other: no effects on gestation length, size of pups, total number of young, stillbirths

Observed effects

Conception rate: Of the 5 groups, only the DPPD group and the 702 group at 0.5% had 100% conception, despite all females and males having known fertility. There were no test article related effects on conception rate.

Gestation length: In 3 of 10 rats fed DPPD, gestation length was prolonged compared to the historical normal 22 +/- 1 days. In one DPPD female, the length was 24 days. The other two females died on the 25th day of pregnancy, and prior to parturition. At necropsy, the unborn litters were found to be of normal number and size. All other pregnant females went through normal length gestations, giving birth to litters ranging from 6 to 16 pups. Although the DPPD females, exclusive of the two that died, had litters of normal number, incidence of stillbirths was about 50%. There were no differences from control in the incidence of stillbirths in the 702 treated animals

Any other information on results incl. tables

Mean values for endpoints

Dietary level (%)

Number females pregnant (10 bred)

Gestation

length (days)

Litter size

Pup weight

(grams)

Numbers in litter

(live, dead)

Live, Day 4

0.0

DPPD 1.25

702    1.25

702     0.50

702     0.125

7

10

6

10

9

22

23

22

22

22

7

8

6

10

9

5.8

6.4

5.9

6.2

6.2

10.9/0.7

5.3/5.0

11.8/0.2

9.9/0.3

9.6/1.3

9.3

5.3

11.3

9.1

8.7

Applicant's summary and conclusion

Conclusions:
Test article 702 when given at dietary levels up to 1.25% to females 7 days prior to mating and through mating and gestation, did not affect gestation length, size of pups, total number of young per litter, or stillbirths per litter compared to control animals. In contrast, positive control, N,N’-diphenyl-p-phenylenediamine (DPPD) was associated with increase in incidence of stillborns, but not an effect on numbers of young in the litters or offspring weights. DPPD in the basal diet with adequate vitamin E caused prolonged gestation in 3 of 10 rats which, when lengthened to 25 days, resulted in death before parturition.

Executive summary:

When pregnant rats were given diets containing test article at concentrations of 0.125 to 1.25% of the dry weight of the food, there were no effects on length of gestation, size of pups, or total number of young per litter. There was not an increase compared to control in numbers of stillborn pups in the litters. In comparison, feeding N,N’-diphenyl-p-phenylenediamine (DPPD) was associated with increase in incidence of stillborns, but not an effect on numbers of young in the litters or offspring weights. DPPD in the basal diet with adequate vitamin E caused prolonged gestation in 3 of 10 rats which, when lengthened to 25 days, resulted in death before parturition.