N,N-dimethylbutylamine

Toxicity to reproduction

Administrative data

Endpoint:

fertility, other

Remarks:

assessment of the oestrous cycle before exposure and then during 4-5 and 7-8 weeks of exposure, and assessment of the fertility of female rats and their foetal development

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

It is considered justified to utilise information on this substance in a read across approach since it is a potential metabolite of the registered substance.

Cross-reference

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

fertility, other

Remarks:

assessment of the oestrous cycle before exposure and then during 4-5 and 7-8 weeks of exposure, and assessment of the fertility of female rats and their foetal development

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

meets generally accepted scientific standards, well documented and acceptable for assessment, the female rats were exposed for 8 weeks prior to mating which is in line with the guideline which recommends an exposure of two complete oestrous cycles prior to mating, however the animal numbers of 11-17 females per dose group were lower than recommended in the guidelines 415 and 416 but higher than recommended in the screening test (guideline 421).

Reason / purpose for cross-reference:

other: read-across target

Principles of method if other than guideline:

Female rats were given aqueous solutions of n-butanol containing 0.24, 0.8 and 4% n-butanol (0.3; 1.0 and 5.0 g/kg/day) for 8 weeks before and during gestation. The control animals received tap water. The experiment was performed in two stages. The first comprised of the assessment of the oestrous cycle before exposure and then during 4-5 and 7-8 weeks of exposure, and the second stage of the fertility of female rats and their foetal development.

GLP compliance:

no

Remarks:

data published

Species:

rat

Strain:

not specified

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Own breeding colony (Imp:DAK)
- Age at study initiation: (P) females: 10 wks; (untreated males: 17 weeks)
- Weight at study initiation: (P) Females: 180-200 g
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 22 °C
- Humidity (%): 45-55 %
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: drinking water

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
the test substance was mixed with drinking water, the stability of the aqueous n-butyl alcohol solutions was assessed on several consecutive days

Details on mating procedure:

- M/F ratio per cage: no data
- Length of cohabitation: 3 weeks with untreated males
- Proof of pregnancy: [sperm in vaginal smear] referred to as [day 0] of pregnancy
- After successful mating each pregnant female was caged (how): no data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of the aqueous n-butyl alcohol solutions was assessed on several consecutive days after their preparation using a Varian Aerograph 2800 gas chromatograph equipped with FID. The column was glass (2 in x 2 mm id .) packed with Porapak Q. The operating conditions were: carrier gas flow (nitrogen) 30 cm3/min; hydrogen 30 cm3/min; air 300 cm3/min; the temperature of the column, injection part and detector were 200°C, 200°C, 230°C, respectively. It was determined that the aqueous n-butyl alcohol solutions were stable within the concentration range used in the experiment (0.24-4%).

Duration of treatment / exposure:

Exposure period: 8 weeks premating, mating (max. 3 weeks) , gestation day 0 - 20

Frequency of treatment:

daily, continuous

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

(0% in water)

Dose / conc.:

300 mg/kg bw/day (nominal)

Remarks:

(0.24% in water)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Remarks:

(0.8% in water)

Dose / conc.:

5 000 mg/kg bw/day (nominal)

Remarks:

(4% in water)

No. of animals per sex per dose:

11-17 females per dose

Control animals:

yes, concurrent vehicle

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: The general behaviour of the animals was observed throughout the experiment.

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: Weight gain was monitored every week in the nonpregnant females and on days 3, 7, 10 and 17 of gestation in the pregnant animals

FOOD CONSUMPTION:
- The daily intake of food was monitored every week in the nonpregnant females and on days 3, 7, 10 and 17 of gestation in the pregnant animals.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: The daily intake of water or n-butanol solutions was monitored every week in the nonpregnant females and on days 3, 7, 10 and 17 of gestation in the pregnant animals.

Oestrous cyclicity (parental animals):

Vaginal smears to assess the oestrous cycle were taken daily between 8 a.m. and 10 a.m. in all animals for 14 consecutive days before exposure and then during the 4-5 and the 7-8 the weeks of exposure. Smears were stained by the Shorr method.

Postmortem examinations (parental animals):

SACRIFICE
- Maternal animals: All surviving animals [on day 20 of gestation]

GROSS NECROPSY
not specified

HISTOPATHOLOGY / ORGAN WEIGHTS
not specified

Statistics:

In the case of variance homogeneity, one-way variance analysis and Dunnett tests were used in the case of heterogeneity Kruskal-Wallis variance analysis was followed by non-parametric tests. Frequency data was analyzed with a Fisher exact probability test. The consumption of food and water or n-butanol solution, and body weight gain of dams were evaluated with two-way variance analysis and Scheffe test for multiple comparison.

Clinical signs:

no effects observed

Description (incidence and severity):

The general appearance and behaviour of the animals exposed to n-butyl alcohol given in drinking water during the 8 weeks, were similar to that of the control animals.

Mortality:

no mortality observed

Description (incidence):

There were no cases of mortality in either group.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Body weight gain of the animals exposed to n-butyl alcohol given in drinking water during the 8 weeks was similar to that of the control animals.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Food consumption of the animals exposed to n-butyl alcohol given in drinking water during the 8 weeks was similar to that of the control animals.

Haematological findings:

no effects observed

Description (incidence and severity):

Haemoglobin concentration and haematocrit values did not differ between the exposed and control group

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No data

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

The duration of the cycle in the control rats and the exposed female rats was similar, 4 days on average. The duration of the individual stages of the oestrous cycle was not dependent on exposure to n-butanol and was similar to that observed in the control animals.

Reproductive performance:

no effects observed

Description (incidence and severity):

No differences were observed between control and treated animals

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no effects observed

Critical effects observed:

no

Remarks on result:

not measured/tested

Critical effects observed:

not specified

Reproductive effects observed:

no

Conclusions:

Under the conditions of the study, there were no differences with regard to reproductive performance observed between control and treated animals. The duration of the cycle in the control rats and the exposed female rats was similar, 4 days on average. The duration of the individual stages of the oestrous cycle was not dependent on exposure to n-butanol and was similar to that observed in the control animals. No other notable effect as a result of treatment with the test material was noted.

Executive summary:

Three treatment groups consisting of 11-17 females were given aqueous solutions of n-butanol containing 0.24; 0.8 and 4% n-butanol (0.3; 1.0 and 5.0 g/kg bw/day), respectively; 16 control animals received tap water.

The experiment was performed in two stages. The first stage comprised of the assessment of oestrus cycle, the second - fertility and foetal development. Vaginal smears to assess the oestrous cycle were taken daily between 8 a.m. and 10 a.m. in all animals for 14 consecutive days before exposure and then during the 4 -5 and the 7 -8 the weeks of exposure. Smears were stained by the Shorr method.

After 8 weeks of treatment all the females were mated with untreated 17-week-old male rats for a maximum of 3 weeks. The day of detection of spermatozoa in the vaginal smears was assumed to be day 0 of gestation. The administration of n-butanol was continued throughout the mating, and gestation period. The general behaviour of the animals was observed throughout the experiment. Weight gain and the daily intake of food and water or n-butanol solutions was monitored every week in the nonpregnant females and on days 3, 7, 10 and 17 of gestation in the pregnant animals. The female rats were killed on day 20 of gestation under ethyl ether anaesthesia. An assessment of teratogenicity, embryo- and foetotoxicity was performed. The uterus was opened and the number of live foetuses, dead foetuses, early and late resorptions sites were recorded. Total implantation values were calculated as the sum of the number of foetuses and resorption sites in each female rat.

Live foetuses were measured for body weight, crown-rump length and examined for external malformations. Approximately half of the live foetuses from each litter were preserved in 95% ethanol for subsequent skeletal examination after staining with Alizarin S. The remaining foetuses were preserved in Bouin fluid for visceral examination.

Under the conditions of the study, there were no differences with regard to reproductive performance were observed between control and treated animals. The duration of the cycle in the control rats and the exposed female rats was similar, 4 days on average. The duration of the individual stages of the oestrous cycle was not dependent on exposure to n-butanol and was similar to that observed in the control animals. No other notable effect as a result of treatment with the test material was noted.

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

N,N-dimethylbutylamine

EC Number:

213-156-1

EC Name:

N,N-dimethylbutylamine

Cas Number:

927-62-8

Molecular formula:

C6H15N

IUPAC Name:

N,N-dimethylbutylamine

Results and discussion

Results: P0 (first parental generation)

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no effects observed

Target system / organ toxicity (P0)

Critical effects observed:

no

Results: F1 generation

Effect levels (F1)

Remarks on result:

not measured/tested

Target system / organ toxicity (F1)

Critical effects observed:

not specified

Overall reproductive toxicity

Reproductive effects observed:

no

Applicant's summary and conclusion

Conclusions:

Under the conditions of the study, there were no differences with regard to reproductive performance observed between control and treated animals. The duration of the cycle in the control rats and the exposed female rats was similar, 4 days on average. The duration of the individual stages of the oestrous cycle was not dependent on exposure to n-butanol and was similar to that observed in the control animals. No other notable effect as a result of treatment with the test material was noted.

Executive summary:

Three treatment groups consisting of 11-17 females were given aqueous solutions of n-butanol containing 0.24; 0.8 and 4% n-butanol (0.3; 1.0 and 5.0 g/kg bw/day), respectively; 16 control animals received tap water.

The experiment was performed in two stages. The first stage comprised of the assessment of oestrus cycle, the second - fertility and foetal development. Vaginal smears to assess the oestrous cycle were taken daily between 8 a.m. and 10 a.m. in all animals for 14 consecutive days before exposure and then during the 4 -5 and the 7 -8 the weeks of exposure. Smears were stained by the Shorr method.

After 8 weeks of treatment all the females were mated with untreated 17-week-old male rats for a maximum of 3 weeks. The day of detection of spermatozoa in the vaginal smears was assumed to be day 0 of gestation. The administration of n-butanol was continued throughout the mating, and gestation period. The general behaviour of the animals was observed throughout the experiment. Weight gain and the daily intake of food and water or n-butanol solutions was monitored every week in the nonpregnant females and on days 3, 7, 10 and 17 of gestation in the pregnant animals. The female rats were killed on day 20 of gestation under ethyl ether anaesthesia. An assessment of teratogenicity, embryo- and foetotoxicity was performed. The uterus was opened and the number of live foetuses, dead foetuses, early and late resorptions sites were recorded. Total implantation values were calculated as the sum of the number of foetuses and resorption sites in each female rat.

Live foetuses were measured for body weight, crown-rump length and examined for external malformations. Approximately half of the live foetuses from each litter were preserved in 95% ethanol for subsequent skeletal examination after staining with Alizarin S. The remaining foetuses were preserved in Bouin fluid for visceral examination.

Under the conditions of the study, there were no differences with regard to reproductive performance were observed between control and treated animals. The duration of the cycle in the control rats and the exposed female rats was similar, 4 days on average. The duration of the individual stages of the oestrous cycle was not dependent on exposure to n-butanol and was similar to that observed in the control animals. No other notable effect as a result of treatment with the test material was noted.