But-2-yne-1,4-diol

Toxicity to reproduction

Administrative data

Endpoint:

one-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

But-2-yne-1,4-diol

EC Number:

203-788-6

EC Name:

But-2-yne-1,4-diol

Cas Number:

110-65-6

Molecular formula:

C4H6O2

IUPAC Name:

but-2-yne-1,4-diol

Details on test material:

- Name of test material (as cited in study report): Butindiol
- Analytical purity: 99.5 %

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Boehringer Ingelheim, Biberach
- Age at study initiation: male/female (28 +/-1) days
- Housing: individually, in type DK III stainless steel wire mesh cages
- Diet : ad libitum (Kliba maintenance diet rat/mouse/hamster meal, Klingentalmühle AG)
- Water : Drinking water used to prepare aqueous Butindiol solutions was of tap water quality. Water was supplied to the animals in the control group, and aqueous Butindiol solutions were supplied to the animals in the groups 01 - 03 (10; 80 and 500 ppm) (Makrolon drinking bottles, 300 ml)
- Acclimation period: 6 days


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

Administration / exposure

Route of administration:

oral: drinking water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Drinking water solutions were prepared once or twice a week. The required weight of test substance was added to the appropriate amount of drinking water and agitated with a magnetic stirrer until the test substance was completely dissoved (about 3 minutes)

Details on mating procedure:

- M/F ratio per cage: 1:1 or 1:2
- Length of cohabitation: overnight, max. 2 weeks
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged: individually, nesting material was provided.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The drinking water was regularly assayed for chemical contaminants by the municipal authorities of Frankenthal and Technical Services of BASF Aktiengesellschaft as well as for the presence of microorganisms by a contract laboratory.

Duration of treatment / exposure:

Premating exposure period (males): 76 days
Premating exposure period (females): 76 days

duration of test: 22 weeks

Frequency of treatment:

daily, continuous

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0, 10, 80, 500 ppm
Basis:
nominal in water
F0 parents and reared F1 weanlings

Doses / concentrations 2

Remarks:

Doses / Concentrations:
ca. 0; 1; 7.6 and 40 mg/kg-bw/day
Basis:
actual ingested
F0 parents

Doses / concentrations 3

Remarks:

Doses / Concentrations:
ca. 1.8; 13.7; 76.9 mg/kg-bw/day
Basis:
actual ingested
Reared F1 weanlings

No. of animals per sex per dose:

25

Control animals:

yes, concurrent vehicle

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly. F0 females also weighed on days 0, 7, 14, and 20 of gestation and days 1,4,7, 14 and 21 after birth.
- The body weights of the selected F1 animals were additionally determined on the day of preputial separation/vaginal opening

FOOD AND WATER CONSUMPTION: Water consumption of the F0 parents was determined regularly during premating (once weekly over a period of 3 days each), and additionally during gestation (days 0-1, 6-7, 13-14, 19-20 p.c.) and lactation (days 1-2, 4-5, 7-8, 14-15 p.p.). Food consumption of the F0 parents was determined regularly during premating (once weekly over a period of 7 days each), and additionally during gestation (days 0-7, 7-14, 14-20 p.c.) and lactation (days 1-4, 4-7, 7-14 p.p.). Food and water consumption of the selected F1 animals was determined once weekly (over a period of 7 days for food consumption and of 3 days for water consumption).

Oestrous cyclicity (parental animals):

Estrous cycle data were evaluated for F0 females over a three week period prior to mating for the first pregnancies and throughout the following mating period (up to 14 days) until evidence of mating occurred. Moreover, the estrous stage of each female was determined on the day of scheduled sacrifice.

Sperm parameters (parental animals):

Various sperm parameters (sperm head counts, morphology) were assessed in F0 males of the control group and high dose group at scheduled sacrifice or shortly thereafter, while sperm motility was examined in all F0 parental males at scheduled sacrifice.

Litter observations:

The F1 pups were sexed, and weighed on the day after birth and on days 4, 7, 14 and 21 post partum. Their viability was recorded. Selected F1 weanlings were reared and sexual maturation (day of preputial separation/vaginal opening) was determined.

Postmortem examinations (parental animals):

All F0 parental animals were assessed by gross pathology (including weight determinations of several organs) and subjected to an extensive histopathological examination, special attention being paid to the organs of the reproductive system.

Postmortem examinations (offspring):

All pups and F1 animals that were selected to be reared to sexual maturity were examined macroscopically at necropsy (including weight determinations of brain, spleen and thymus in one pup/sex/litter).

Reproductive indices:

Parental animals were examined for their mating and reproductive performances.

Offspring viability indices:

Viability was recorded.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

High dose females only. Reduction in food consumption and lower body weight and weight gain.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

High dose females only. Reduction in food consumption and lower body weight and weight gain.

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Test substance intake: High and mid doses only. Most pronounced in F0 females at high dose during gestation and lactation.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS) - no substance related mortalities or clinical signs of disturbance of behaviour in any of the male and female F0 animals in any of the dose groups.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS) - statistically significant reduction in food consumption was noted for F0 females during all periods of administration for the high dose group. F0 females of the high dose group revealed lower body weights/body weight gain during all periods of administration and most pronounced during the period of lactation.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS) - statistically significant reductions in drinking water consumption were observed for the high and mid dose groups and were most pronounced in F0 females at 500 ppm during the period of gestation and of lactation.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS) - no substance related effects

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS) - no substance related effects

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS) - no substance related effects

ORGAN WEIGHTS (PARENTAL ANIMALS) - statistically significant increased absolute/relative kidney weights (both F0 sexes) and absolute/relative liver weights (F0 females) as well as statistically significantly decreased absolute/relative weights of the adrenal glands and of thymus (F0 females) at the 500 ppm dose level and statistically significantly increased absolute/relative kidney weights (both F0 sexes) and absolute/relative liver weights (F0 females) at the 80 ppm dose level.

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Remarks:

general, systemic toxicity

Effect level:

ca. 1 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Based on reduced water intake and organ weight impairment of F0 parents

2

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Effect level:

ca. 7.6 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Based on reduced water and food consumption, body weight, and absolute and relative organ weight observed in F1 pups.

3

Key result

Dose descriptor:

NOAEL

Remarks:

reproductive toxicity

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Based on reproductive performance and fertility of F0 parents

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

High dose only. Body weight and weight gain.

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

High dose only. Absolute and relative organ weights for brain and thymus.

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Details on results (F1)

VIABILITY (OFFSPRING) - no substance-related effects

CLINICAL SIGNS (OFFSPRING) - no substance-related effects

BODY WEIGHT (OFFSPRING) - statistically significantly reduced in the 500 ppm group from day 7 postpartum (body weight) and day 14 postpartum (body weight gain).

SEXUAL MATURATION (OFFSPRING) - no substance-related effects

ORGAN WEIGHTS (OFFSPRING) - statistically significantly impaired absolute and relative organ weights for brain and thymus in the 500 ppm group.

GROSS PATHOLOGY (OFFSPRING) - no substance-related effects

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

ca. 7.6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

water consumption and compound intake

organ weights and organ / body weight ratios

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

The mean dose of 1,-Butynediol (B3D) administered (during premating (F0 parental animals) was approximately 1 mg/kg body weight/day in the10 ppm group, approx. 7.6 mg/kg body weight/day in the 80 ppm group and approx. 40 mg/kg body weight/day in the 500 ppm group. Based on their water intake, the mean substance intake for reared F1 weanlings was calculated to about 1.8, 13.7 and 76.9 mg/kg bw/day according to the drinking water concentrations of 10, 80 and 500 ppm, respectively.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study the NOAEL for reproductive performance and fertility is 500ppm (about 40 mg/kg bodyweight/day) for the F0 parental rats. The NOAEL for general, systemic toxicity of the test substance is 10 ppm (about 1 mg/kg body weight/day) for the F0 parental males and females. The NOAEL for developmental toxicity (growth and development of the offspring) could be fixed at 80 ppm (about 7.6 mg/kg body weight/day)
for the F1 progeny. Thus, indications for developmental toxicity occurred only at a dose which was also toxic to the parental animals.