Aluminium tributanolate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Assessment of the effect of n-butanol given to female rats in drinking water on fertility and prenatal development of their offspring

Author:

Sitarek K, Berlinska B, Baranski B

Year:

1994

Bibliographic source:

International Journal of Occupational Medicine and Environmental Health 7(4): 365-370

Materials and methods

Test guideline

Qualifier:

no guideline followed

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:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Butan-1-ol

EC Number:

200-751-6

EC Name:

Butan-1-ol

Cas Number:

71-36-3

Molecular formula:

C4H10O

IUPAC Name:

butan-1-ol

Details on test material:

- Name of test material (as cited in study report): n-butyl alcohol

Test animals

Species:

rat

Strain:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Own breeding colony (Imp:DAK)
- Age at study initiation:10 wks (females)
- Weight at study initiation: 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

Administration / exposure

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

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%).

Details on mating procedure:

- Impregnation procedure: [cohoused]
- If cohoused:
- M/F ratio per cage: no data
- Length of cohabitation: 3 weeks with untreated males
- Verification of same strain and source of both sexes: [yes]
- Proof of pregnancy: [sperm in vaginal smear] referred to as [day 0] of pregnancy

Duration of treatment / exposure:

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

Frequency of treatment:

daily, continuous

Duration of test:

until day 20 of gestation

No. of animals per sex per dose:

11-17 females per dose

Control animals:

yes

Examinations

Maternal 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.

POST-MORTEM EXAMINATIONS: No data

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [half per litter]
- Skeletal examinations: Yes: [half per litter]
- Head examinations: No data

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.

Indices:

No data

Historical control data:

No data

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

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

no effects observed

Haematological findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Maternal developmental toxicity

Pre- and post-implantation loss:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

Details on maternal toxic effects:
The general appearance and behaviour of the animals exposed to n-butyl alcohol given in drinking water during the 8 weeks, as well as body weight gain, food and liquid intake were similar to that of the control animals . There were no cases of mortality in either group.
Integral toxicity indexes observed in the female rats, such as body weight gain during gestation, food and liquid (water or butanol solutions) intake, absolute and relative organ weights, hemoglobin concentration and haematocrit values did not differ between the exposed and control groups.

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day (nominal)

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

no effects observed

Details on embryotoxic / teratogenic effects:

Details on embryotoxic / teratogenic effects:
The unit of statistical analysis in this study was the individual foetus, not the litter.
At 5000 mg/kg bw the crown-rump length was decreased (mean of 4.0 to 3.8 cm for the control and treated group, respectively) . Developmental effects were reported in all 3 dose groups. Skeletal effects were limited to an extra 14th rib in 1 foetus in the low dose group and 2 foetuses in the high dose group, and wavy ribs in 1 foetus in the low dose group. CNS defects included dilation of either the subarachnoid space or lateral and/or third ventricles of the brain, or external or internal hydrocephalus. Dilated renal pelves were also observed. Of the 65 control foetuses examined for skeletal effects, none had an extra fourteenth or wavy rib(s) or any other skeletal malformation or variation. Two of the 61 control foetuses examined for visceral anomalies had dilatation of the lateral and/or third ventricles of the brain, while none had dilatation of the subarachnoid spaceor external or internal hydrocephalus. Although the authors considered all 3 dose levels as related to increased foetal effects when compared to controls, there was no dosedependent increase. However, since no foetus of the middle dose group was affected, and only 2 in the low dose, it appears probable that the observations in the low dose group were not treatment related.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day (nominal)

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

The unit of statistical analysis in this study was the individual foetus, not the litter.

The authors considered the recorded developmental effects (dilatation of the brain ventricles/spaces or renal pelvis, internal hydrocephalus, wavy or extra ribs) as being related to butan-1-ol and assessed these findings as variations or delayed development commonly seen in large historical control databases. Of significance, the incidence of all but one of the reported developmental effects in the actual control population was 0%. In the MARTA-MTA 1995 database, using Crl: CD BR rat, the incidence of "cerebral ventricle, enlargement" was 2%/foetus or 4.4%/litter, and the incidence of "renal pelvis, dilated" 0.95%/foetus or 5.2%/litter (Wise and Petrere, 1996). The "malformations" reported that were assessed as "variations" in other databases should be classified based on the incidence within the rat strain. The incidence of variations within the rat strain used in this study is unknown, since the authors used a rat strain common only to their laboratory. The laboratory diet was also unique. Since the strain of rat and type and quality of diet can have profound effects on rates of variations and malformations, and since there is no historical database available for the strain tested, the term “variation" has to be assigned with reservation. However, the term may still be appropriate since the variations reported are also common in several rat strains frequently used in the. In fact, Nelson et al (1989) described some of these variations following inhalation exposure to butan-1-ol. It should not be surprising that high oral doses of butan-1 -ol (corresponding to approx. twice the LD₅₀) that alter normal maternal physiology would also cause an increase in common variations in laboratory rodents. Thus, the developmental effects seen by Sitarek et al (1994) cannot be regarded as a selective foetal effect.

Skeletal and visceral observation

	Control	n-butanol 0.3 g/kg/day	n-butanol 1.0 g/kg/day	n-butanol 5.0 g/kg/day
No. of foetuses (litters) examined:	126(12)	154(14)	146(12)	102(9)
Visceral observation
No. of foetuses (litters) examined:	61(12)	73(14)	71(12)	51(9)
% of foetuses (litters)
with dilation of:	2(8)	25*(64)*	32*(83)*	41*(100)*
subarachnoid space	0	3(14)*	10*(25)*	20*(78)*
lateral ventricle and/or third ventricle of the brain	2(8(	23*(57)*	17*(67)*	25*(78)*
unilateral renal pelvis	0	0	7*(42)*	0
bilateral renal pelvis	0	0	4(25)	0
% of foetuses (litters) with
congenital defects:	0	0	7*(33)*	4(22)*
external hydrocephalus	0	0	3*(17)*	0
internal hydrocephalus	0	0	7*(25)*	4(22)*
Skeletal observations
No. of foetuses (litters) examined:	65(12)	81(14)	75(12)	51(9)
% of foetuses (litters)
with delayed ossification:	15(67)	16(50)	24(58)	33*(67)
% of foetuses (litters)
with congenital defect:	0	1(7)*	0	2(11)*
14th rib	0	0	0	2(11)*
wavy ribs	0	1(7)*	0	0

 * significantly different from the control (p<0.05)