(Z)-2-butene-1,4-diol

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

BASF AG

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

But-2-ene-1,4-diol

EC Number:

203-787-0

EC Name:

But-2-ene-1,4-diol

Cas Number:

110-64-5

Molecular formula:

C4H8O2

IUPAC Name:

2-Butene-1,4-diol

Constituent 2

Reference substance name:

(Z)-2-butene-1,4-diol

EC Number:

228-085-1

EC Name:

(Z)-2-butene-1,4-diol

Cas Number:

6117-80-2

Molecular formula:

C4H8O2

IUPAC Name:

but-2-ene-1,4-diol

Details on test material:

- Name of test material (as cited in study report): 2-Butene-1,4-diol

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Germany
- Age at study initiation: 11-12 weeks (males), 10-11 weeks (females)
- Housing: individually, DKII stainless stell cages/ Makrolon type M II cages
- Diet (ad libitum): Kliba maintenance diet mouse/rat
- Water (ad libitum):drinking water
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24 °C
- Humidity (%): 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: doubly distilled water

Details on mating procedure:

At least 13 days after the beginning of treatment, males and females from the same dose group were mated overnight in a ratio of 1:1. As soon as sperm was detected in the vaginal smear, the mating was discontinued.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

The male rats were treated for 29 days
The female rats were treated for 50 days.

Frequency of treatment:

once daily

Details on study schedule:

Males: approx. 2 weeks premating, 2 weeks mating and post mating
Females: approx. 2 weeks premating, during mating and gestation through day 4 after delivery.

Doses / concentrations

Remarks:

Doses / Concentrations:
20, 60, and 200 mg/kg-bw
Basis:
other: amount of test substance administered by oral gavage

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

The daily volume administered was 10 ml/kg of bodyweight. The calculation of the volume administered was based on the most recent individual body weight. Food consumption of the F0 parents was determined regularly during premating, after the mating period and, in dams, during gestation and lactation periods.

Positive control:

None

Examinations

Parental animals: Observations and examinations:

GENERAL OBSERVATIONS:
- A detailed clinical observation was performed in all animals once before the initial test substance administration and there after at weekly intervals. The animals were examined for signs of toxicity or mortality at least once a day. The F0 parental animals were examined for their mating and reproductive performances.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Before first dose and weekly thereafter

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly

FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Regularly during premating, after the mating period and, in dams, during gestation and lactation periods.

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Males on study day 29, Females on study day 50
- Anaesthetic used for blood collection: Yes (carbon dioxide)
- Animals fasted: No data
- How many animals: 5

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Males on study day 29, Females on study day 50
- Animals fasted: No data
- How many animals: 5

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Males on study day 28, Females on study day 42
- Dose groups that were examined: low, medium, and high dose groups
- Battery of functions tested: functional battery and motor activity measurement

Litter observations:

The pups were sexed on day 0 p.p. and weighed one day after their birth and on day 4 post partum. Their viability was recorded.

Postmortem examinations (offspring):

All pups were sacrificed four days after birth under CO2 anesthesia and examined macroscopically for external and visceral findings at necropsy.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Salivation after treatment was observed in several males of the high dose from week 2 to the end of the treatment period as well as in females of the high dose during study weeks 6 and 7. This finding, reported for these high dose groups, was considered as been related to the treatment.
No substance-related clinical findings were observed in any other treated group.

After test substance administration, at least one female from the high dose group showed salivation during the lactation period.
Several female animals from the high dose groups did not nurse their F1 pups properly in the beginning of the lactation period (5/10 females - on day O p.p. and 1/10 female - on day 1 p.p.). The pups from these animals were found dead between days 1 and 2 p.p ..
Pups from two females which did not show any nursing problem, were also found dead on days 1 and 2 p.p ..
All these findings were related to the administration of the high dose of the test substance.

No substance-related findings during lactation were observed in any other treated group.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A significant impairment in body weights was observed in males from the high dose group during the treatment period (max. -9%). The body weight change of the same treated group was found 59% decreased, when compared to controls, from study week 0 to 4.
From gestation day 7 onwards, the body weights of the high dose females were markedly lower (max. -14%) when compared to concurrent control. If calculated for the entire gestation period (days 0-20), the high dose animals gained statistically significantly less weight (-29%) than controls.
During the lactation period, body weights of females from the high dose group were observed significantly decreased (from day O to 4; max -16%) as well as body weight gain, for the same dose group, was found 77% reduced when compared to control animals.
Body weight from females treated with the high dose of the test substance was reported significantly reduced on study weeks 6 and 7 (max. -16% and -8%, respectively). Due to a marked reduction found in the body weight of animals from the high dose group after weaning (study week 6), the body weight change of this group of animals was found significantly higher than control animals.
The reduction in body weights observed after the high dose of the test substance administration in males and females groups are considered as being related to treatment.

Body weights/body weight gains of FO parental animals in low and mid test groups were not influenced by the test substance administration. All differences in body weights and body weight gains observed for these rats were without any biological relevance.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A significant reduction in food consumption was observed in male (-12%) and female
(-17%) animals treated with the high dose of the test substance during the first week of administration. Food consumption of the same female dose group was also found below than controls in the beginning of gestation period (-10%; days 0-7) and during lactation (-31%; days 0-4).
All these findings were related to the high dose of the test substance treatment.
No significant differences in food consumption were observed in any other treated group.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Hematological examinations revealed no treatment-related changes in males. In females, slight, but statistically significant decreases in hemoglobin and hematocrit were observed in the peripheral blood of the mid and high dose animals.
No treatment-related effects were seen in the other hematological parameters.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Compound-related differences in serum enzyme activities were not evident at any dose level in either males or females.
Blood chemistry investigations showed significantly increased potassium, inorganic phosphate and albumin concentrations in the circulation of the high dose animals of either sex. Decreased creatinine and glucose levels as well as increased total bilirubin concentrations were also found in the high dose males. Moreover, increased calcium and magnesium concentrations and decreased chloride levels were recorded in the serum of the high dose females. In the males mid dose potassium was increased. This finding, however, was not of sufficient magnitude to be considered adverse.

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, treatment-related

Description (incidence and severity):

Males treated with the high dose of the test substance showed a reduced number of rearings when compared to controls (-50%). Although this finding was not statistically significant, it was related to the test substance treatment.
Regarding the overall motor activity a reduction of beams numbers was observed in male animals treated with the high dose of the test substance from interval 1 to interval 6. This finding is considered as being related to the treatment.

No substance-related findings were observed in any other treated group.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Treated female animals had a slightly higher incidence of focal pelvic mineralization in kidney (0/2/2/6). This finding was regarded to be incidental as in almost every animal the kidney was only unilaterally affected, the finding was only minimal to slight and there was no clear dose-response relationship.
All other microscopic findings recorded were either single observations, or they occurred in control animals only, or they were recorded at a low incidence or at a biologically comparable incidence and graded severity in control and high dose males and/or females. They were all regarded to be of spontaneous origin and to have developed unrelated to treatment.

Histopathological findings: neoplastic:

no effects observed

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Description (incidence and severity):

The male mating index reached 100% in all substance treated groups including the control group.
The male fertility index reached 100% in all substance treated groups including the control group.
The female mating index calculated after the mating was 100% in all test groups.
The female fertility index was 100% in all test groups.
The gestation index was 100% in all groups of females.
The mean duration of gestation period was similar in all test groups (between 21.9 and 22.2 days).
The mean number of implantation sites per dam was found statistically significantly decreased in the high dose group (11.2 implantations against 14.0 in the control group). Furthermore, post implantation loss was 20% in this dose group, indicating intrauterine embryo-fetolethality.
A significant reduction of 30% in the number of pups delivered in the high dose group was observed.
The live birth index was slightly but not significantly impaired (94% compared to controls: 98%) in animals from the high dose group.
The female reproduction and delivery parameters assessed in this study were not affected in groups of animals treated with the low and mid dose of the test substance.

Details on results (P0)

CLINICAL EXAMINATIONS
Test group 3 (200 mg/kgbw/day):
salivation in males after treatment from second week onwards
slight impairment of motor activity in males from interval 1 to 6
significant reduction in food consumption during the first week of treatment in both sexes (-12% males and -17% females)
significant impairment of body weights and body weight gain (max.-9% and -59%, respectively) in males
significant impairment of females body weights and body weight gain in studyweeks 6 and 7 (max.-16% and -8%, respectively)
Test groups 1 and 2 (20 & 60 mg/kg bw/day):
- no treatment-related effects were observed

FEMALES CLINICAL EXAMINATIONS DURING GESTATION
Test group 3 (200 mg/kgbw/day):
salivation before and after test substance administration
significant reduction in food consumption within the first week of gestation (-10%),
significant impairment of body weights and body weight gain (max.-14% and-29%, respectively)
Test groups 1 and 2 (20 & 60 mg/kg bw/day):
- no treatment-related effects were observed

FEMALE CLINICAL EXAMINATIONS DURING LACTATION (DAYS 0-4 POSTPARTUM)
Test group 3 (200 mg/kgbw/day):
salivation after test substance administration
significant reduction in food consumption (-31%)
significant impairment of body weights and body weights gain (max.-16% and-77%, respectively)
Test groups 1 and 2 (20 & 60 mg/kg bw/day):
- no treatment-related effects were observed

CLINICAL PATHOLOGY
Test group 3 (200 mg/kgbw/day):
increased potassium, inorganic phosphate and albumin in both sexes
increased total bilirubin in males and calcium and magnesium in females
decreased creatinine and glucose in males and hemoglobin, hematocrit andchloride in females
Test groups 2 (60 mg/kg bw/day):
- decreased hemoglobin and hematocrit in females
Test group 1 (20 mg/kg bw/day):
- no treatment-related effects were observed

PATHOLOGY
Test group 3 (200 mg/kgbw/day):
significant decrease in terminal body weight in males and females
significant increase of relative kidney weights in male animals
significant increase of absolute and relative liver weights in male and female animals
minimal to moderate storage of alpha 2u protein in epithelial cells of proximal tubules in all male animals
minimal to moderate centrolobular hypertrophy in the liver of nine male and nine female animals
minimal to slight hypertrophy/hyperplasia of the thyroid follicular cells of three female animals
significant increase of absolute and relative kidney weights in male animals
significant increase of absolute and relative liver weight in males
significant increase of relative liver weights in females
minimal to slight storage of alpha 2µl protein in epithelial cells of proximal tubules in five male animals
Test group 2 (60 mg/kg bw/day):
- minimal centrolobular hypertrophy in the liver of four female animals
Test group 1 (20 mg/kg bw/day):
- no treatment-related effects were observed

FERTILITY/REPRODUCTIVE PERFORMANCE
Test group 3 (200 mg/kgbw/day):
significantly reduced implantation sites numbers per dam (11.2/14)
significantly increased postimplantation loss (20%)
reduced number of pups delivered (-30%)
higher number of stillborn pups (6 pups from 4 litters vs. 2 pups from 2 litters in thecontrol)
impaired nursing (5/10 dams) and insufficient maternal care (1/10 dams)
complete loss of pups (7/10 dams)
Test groups 1 and 2 (20 & 60 mg/kg bw/day):
- no treatment-related effects were observed

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Effect level:

60 mg/kg bw/day

Sex:

female

Basis for effect level:

reproductive performance

Remarks on result:

other: Whereas the cohabitation, fertility and integrity of the reproductive organs of both male and female rats were not affected, a substantially impaired pre- and postnatal development of the offspring was observed at maternally toxic dose (200 mg/kg b.w.).

2

Key result

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

reproductive performance

3

Dose descriptor:

NOAEL

Effect level:

20 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: systemic toxicity

Results: P1 (second parental generation)

General toxicity (P1)

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

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:

not examined

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:

not examined

Results: F1 generation

General toxicity (F1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

One pup of the FO high dose group showed hypothermia. This single occurrence was considered as being incidental and spontaneous in nature.
The F1 pup clinical observations did not reveal any additional abnormalities in all test groups.

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, treatment-related

Description (incidence and severity):

An increase in the number of pups, which died (42%) or were cannibalized (16%), in the FO high dose group was observed. Thus, the viability index, as an indicator for pup mortality between days O and 4 post partum, was found significantly lower (38%) when compared to control group (99%).
One pup from the FO low and one from the FO mid dose treatments were cannibalized. These single occurrences were assessed as being spontaneous in nature having no relationship with the test substance administration. The viability index was not affected for both dose groups (99%) when compared to controls.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A significant impairment in body weights and body weight gain (-23% and -34%, respectively) of the pups from the FO high dose females were reported from days 1 to 4 post partum.
The mean pup body weights/pup body weight gain from the low and mid dose animals did not show any statistically significant differences when compared to control groups.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

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):

One male of the examined F1 pups of the high dose group and one male pup from the control group showed hemorrhagic testis at necropsy.
This finding, observed also in the control group, occurred without any clear relation to the test substance treatment. Thus, this occurrence was considered incidental and not biologically relevant.

Histopathological findings:

not examined

Other effects:

no effects observed

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Details on results (F1)

CLINICAL EXAMINATIONS (DAYS 0-4 POST PARTUM)
Test group 3 (200 mg/kgbw/day):
- markedly increased number of pups found dead or cannibalized, viability index 38% (vs. 99% in the control);
- significant impairment of pups body weights and body weight gain (-23% and-34%, respectively)
Test groups 1 and 2 (20 & 60 mg/kg bw/day):
- no treatment-related effects were observed

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

60 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: Viabiity and body weight.

Results: F2 generation

General toxicity (F2)

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

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:

not examined

Histopathological findings:

not examined

Other effects:

not examined

Developmental neurotoxicity (F2)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F2)

Developmental immunotoxicity:

not examined

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In conclusion, the gavage administration of 200 mg/kg body weight/day 2-Butene-1,4- diol to male and female Wistar rats caused distinct systemic toxicity such as salivation, markedly reduced food consumption and retarded body weight development, liver enzyme induction, storage of alpha 2u protein and mild impairment of motor activity in the males as well as mild anemia in the females. Whereas the cohabitation, fertility and integrity of the reproductive organs of both male and female rats were not affected, a substantially impaired pre- and postnatal development of the offspring was observed at this overtly maternally toxic dose.
A dose of 60 mg/kg of body weight/day still evoked liver enzyme induction in both genders, storage of alpha 2u protein in males and mild anemia in females but had no influence on reproduction.
Thus, under the conditions of this reproduction/developmental toxicity screening test the NOAEL (no observed adverse effect level) for reproductive performance is 60 mg/kg of body weight/day for the FO parental rats.
The NOAEL of the test substance for general, systemic toxicity is 20 mg/kg of body weight/day for the FO parental rats of both sexes.
The NOAEL of the test substance for developmental toxicity in the F1 progeny is 60 mg/kg of body weight/day.