Ethyl butyrate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from a peer-reviewed journal.

Data source

Reference

Reference Type:

publication

Title:

Evaluation of the Teratogenic Potential of Octyl Acetate in Rats

Author:

W. C. DAUGHTREY, P. J. WIER,1 K. A. TRAUL,2 R. W. BILES, AND G. F. EGAN

Year:

1989

Bibliographic source:

Fundamental and Applied Toxicology, 13, 303-309 (1989)

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Teratogenic potential toxicity study of test chemical was performed in rats.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Octyl acetate

EC Number:

203-939-6

EC Name:

Octyl acetate

Cas Number:

112-14-1

Molecular formula:

C10H20O2

IUPAC Name:

octyl acetate

Details on test material:

- Name of test material (as cited in study report):Acetate C-8
- Molecular formula:C10H20O2
- Molecular weight :172.266 g/mole
- Substance type:Organic
- Physical state:Liquid
- Impurities (identity and concentrations):No data available

Specific details on test material used for the study:

- Molecular formula:C10H20O2
- Molecular weight :172.266 g/mole
- Substance type:Organic
- Physical state:Liquid
- Impurities (identity and concentrations):No data available

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: (P) x wks; 9 weeks old
- Weight at study initiation: 212 - 216 g female
- Fasting period before study: No data available
- Housing: Animals were housed individually (except during the first week of quarantine and during mating) in suspended stainless-steel cages and All animals were identified by uniquely numbered ear tags during the course of the study.
- Diet (e.g. ad libitum): Food (certified Rodent Chow, Ralston Punna Co.)
- Water (e.g. ad libitum): water, ad libitum
- Acclimation period: 3-week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19- 24 °C (monitored daily)
- Humidity (%): 40-70% (monitored daily)
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): 12-hr photoperiod

IN-LIFE DATES: From: To: No data available

Administration / exposure

Route of administration:

oral: gavage

Type of inhalation exposure (if applicable):

not specified

Vehicle:

water

Remarks:

Distilled

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Test chemical was dissolved in distilled water to give as dose of 0, 100, 500 or 1000 mg/Kg

DIET PREPARATION:
- Rate of preparation of diet (frequency): No data
- Mixing appropriate amounts with (Type of food): No data
- Storage temperature of food: No data

VEHICLE:
- Justification for use and choice of vehicle (if other than water): Distilled water
- Concentration in vehicle: 0, 100, 500 or 1000 mg/Kg
- Amount of vehicle (if gavage): Dose volumes were based on GD 6 body weights throughout the dosing period
- Lot/batch no. (if required): No data
- Purity: No data

Details on mating procedure:

- M/F ratio per cage: No data avaialble
- Length of cohabitation: No data avaialble
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy: Copulatory plug in the vagina
or by observation of sperm in a vaginal rinse were referred to as day 0 of pregnancy
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility. No data avaialble
- Further matings after two unsuccessful attempts: [no / yes (explain)]: No data available
- After successful mating each pregnant female was caged (how): Individually
- Any other deviations from standard protocol: No data avaialble

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No Data Available

Duration of treatment / exposure:

10 days

Frequency of treatment:

Daily

Details on study schedule:

- Rationale for animal assignment (if not random): Females confirmed to have mated were randomly assigned to one of four experimental groups of 22 mated female rats.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 500 and 1000 mg/Kg
Basis:

No. of animals per sex per dose:

Total: 85 Animals
0 mg/kg bw : 22 female
100 mg/kg bw :20 female
500 mg/kg bw :22 female
1000 mg/kg bw :21 female

Control animals:

yes, concurrent vehicle

Details on study design:

No data avaialble

Positive control:

No data avaialble

Examinations

Parental animals: Observations and examinations:

Survival, clinical sign, body weight and body weight change and food consumption were observed.

Oestrous cyclicity (parental animals):

Corpora lutea and Resorptions were examined.

Sperm parameters (parental animals):

No data available

Litter observations:

Fetuses were weighed and sexed.

Postmortem examinations (parental animals):

Organ weight and gross pathology were examined.

Postmortem examinations (offspring):

Examined externally for gross abnormalities, visceral, and skeletal malformations and variations, and crown-rump distance were measured.

Statistics:

Maternal body weight and body weight change, food consumption, uterine data (i.e., corpora lutea, implants, resorptions), and malformation data were analyzed statistically using Bartlett's test of homogeneity of variance (Snedecor and Cochran, 1967) was used to determine if the groups had equivalent variances at the 1 % level of significance. If the variances were not significantly different, the groups were compared using a standard one-way analysis of variance (ANOVA). If significant differences among the means were indicated, Duncan's test (Dunnett, 1964) was performed to determine which treated groups differed from control. Fetal weights and crown-rump lengths were analyzed using individual fetal values by a standard nested analysis of variance, with values nested within dams and dams nested within groups. If differences in groups were indicated, the least-significantdifference technique (Snedecor and Cochran, 1967) was used to determine which treated groups differed from control. If the groups did not have equivalent variances at the 1 % level, then a Kruskal-Wallis test (nonparametric) was used to assess differences in group means (Hollander and Wolf, 1973). If the means were different, a rank sum comparison was used to determine which treatment groups differed from control.

Reproductive indices:

No data avaialble

Offspring viability indices:

No data avaialble

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

When treated with 1000 mg/kg bw, elevated incidences of alopecia, rales, red nasal discharge, and anal-genital staining were observed in treated female rats as compared to control.

Dermal irritation (if dermal study):

not specified

Mortality:

mortality observed, treatment-related

Description (incidence):

When treated with 1000 mg/kg bw, 2 female rats were died one each on GDs 10 and 12, respectively. No effect on mortality of 100 and 500 mg/kg bw treated female rats were observed as compared to control.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

When treated with 1000 mg/kg bw, a statistically significant decreased in mean body weight on on GDs 9, 12, 16, and 20 were observed as compared with control. The effect was most evident during the first several days of dosing, when these animals actually lost weight (GDs 6-9). When treated with 500 mg/kg bw, Statistically significant decrase in mean body weight and body weight changes were observed at several time points as compared with control. These decrase in body weight appeared to occur in an ordered response to dose.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

When treated with 500 and 1000 mg/kg bw, dose-related decreases in food consumption for the Day 6-9, 9-12, and 12- 16 intervals were observed as compared with control.

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

no effects observed

Description (incidence and severity):

When treated with 1000 mg/kg bw, slight increase in resorptions were observed as compared to control. But, the difference was not statistically significant. No statistically significant effect was observed on Corpora lutea/dam, Implants/litter, Resorptions/litter and Live fetuses/litter as compared to control.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

clinical signs

mortality

body weight and weight gain

food consumption and compound intake

Remarks on result:

other:

Target system / organ toxicity (P0)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality / viability:

no mortality observed

Description (incidence and severity):

Mortality: No significant effect was observed on Live fetuses/litter s compared to control.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Body weight:
No significant effect was observed on fetal body weight as compared to control.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Gross pathology:
Tail absent were observed in 1000 mg/kg bw and micrognathia in 500 mg/kg bw as compared to control. No significant differences or dose-related change were observed on crown rump distance of fetuses were observed as compared to control.

Histopathological findings:

effects observed, treatment-related

Description (incidence and severity):

Histopathology:
Visceral examinations:
When treated wtih 1000 mg/kg bw, dilated lateral cerebral ventricles in two fetuses were observed which are anatomical variations previously observed in historical control fetuses.

Skeletal malformations:
When treated wtih 1000 mg/kg bw, Different types of vertebral malformations were observed in four fetuses (four litters) in the form of incomplete ossification but, was not statistically significant as compated to control.

Other effects:

not specified

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not specified

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not specified

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No effect on body weight, gross pathology and histopathology

Remarks on result:

other: No developmental toxic effects were observed

Target system / organ toxicity (F1)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Treatment related:

not specified

Any other information on results incl. tables

Maternal Body Weight And Body Weight Changes^a

	Dose group
Gestational day	0 g/kg (N=20)	0.1 g/kg (N=20)	0.5 g/kg (N=20)	1. 0 g/kg (N=20)
	Body weight (g)
0	216.7 ±22.5	214.8 ± 16.0	213.7 ± 18.3	212.0± 18.5
3	233.3 ±22.4	232.0 ±17.2	230.1 ± 17.8	227.9 ±19.2
6	248.8 ± 23.0	246.1 ±17.8	244.6 ± 20.0	242.9 ± 20.2
9	261.0 ±24.9	256.6 ±18.4	247.3 ±21.2	234.7 ±24.5**
12	279.9 ± 24.3	273.7 ±19.9	261.1 ±23.4*	247.0 ±25.4"
16	306.5 ± 26.0	300.0 ±23.5	288.0 ±27.1	275.3 ± 24.7**
20	368.5 ±28.0	361.3 ±27.7	352.4 ±34.9	338.1 ±26.7*
20^c	295.3 ±23.0	285.6 ±21.1	272.1 ±26.0*	265.1 ±24.3**
	Body weight change (g)
0-6	32.0 ± 3.8	31.3 ± 4.8	30.9 ± 6.8	30.9 ± 6.0
6-9	12.2 ± 4.1	10.6 ± 5.1	2.7 ± 11.3**	-8.1 ± 12.1**
9-12	18.9 ± 4.2	17.1 ± 4.1	13.8 ± 9.4*	13.5 ± 7.9*
12-16	26.6 ± 6.9	26.3 ± 5.6	26.9 ± 8.6	27.3 ± 8.5
16-20	62.0 ± 6.6	61.3 ± 9.0	64.4 ± 10.8	62.8 ± 5.5
0-20	151.8 ± 13.9	146.5 ± 16.4	138.6 ±25.9	126.3 ± 15.5**
6-20^c	46.6 ± 8.5	39.6 ± 9.6	28.8 ±15.0**	22.2 ± 13.3**

^aValues are means ± SD. N = number of dams.

^b From Day 12, W =20; from Day 16, N= 19.

c Body weight corrected for gravid uterine weight.

* Significantly different from control, p≤0.05.

** Significantly different from control, p≤0.01.

Mean food consumption of pregnant rats^a

	Dose group
Gestational day	0 g/kg	0.1 g/kg	0.5 g/kg	1.0 g/kg
0-3	69.2+ 5.9	69.8 ± 5.6	69.2+ 5.7	67.6 ± 5.7
	(21)*	(19)	(22)	(21)
3-6	76.4+ 6.8	72.3 ± 7.8	73.3 ± 6.2	72.5 ± 5.7
	(20)	(18)	(22)	(21)
6-9	76.7 ± 8.1	72.8 ± 7.2	63.7 ± 11.1"	49.3 ±12.3**
	(22)	(19)	(22)	(21)
9-12	80.7 ± 7.5	75.5 ± 8.5	66.9 ± 9.4"	60.5 ± 19.2"
	(21)	(H)	(21)	(18)
12-16	104.3 ± 10.5	101.8 ± 11.9	92.4+ 13.2*	88.8 ± 9.4"
	(22)	(19)	(19)	(19)
16-20	112.7 db 8.5	111.9± 11.6	109.8 ± 14.0	110.0 ± 10.9
	(22)	(20)	(22)	(19)

^aValues are the means ± SD of the amount of diet consumed expressed in grams per rat.

* N is given in parentheses.

* Significantly different from control, p≤ 0.05.

** Significantly different from control, p≤0.01.

Uterine Implantation Data^a

	Dose group
	0 g/kg (N=20)	0.1 g/Kg (N = 20)	0.5 g/kg (N=20)	1.0 g/kg (N =20)
Corpora lutea/dam	16.0 ± 1.6	15.9 ± 2.2	16.1 ± 2.5	16.5 ±2.6
Implants/litter	14.7 ± 1.5	14.7 ± 2.0	14.9 ± 2.1	14.8 ± 1.9
Resorptions/litter	0.6 ±0.7	0.9 ± 1.2	0.6 ± 0.8	1.3± 1.4
Uterine weight (g)	74.9 ± 9.0	75.6 ±12.1	77.8± 13.1	73.0 ±8.8
Live fetuses/litter	7.9 ± 1.9	7.4 ± 1.8	7.0 ± 1.8	6.7 ±2.2
Male	6.2 ±1.6	6.3 ± 1.8	7.2 ± 1.6	6.8 ± 1.9
Female	14.1 ± 1.6	13.7 ± 2.2	14.2 ± 2.0	13.5 ± 1.7
Total	16.0 ± 1.6	15.9 ± 2.2	16.1 ± 2.5	16.5 ±2.6

^aValues are means ± SD. N = number of litters.

Applicant's summary and conclusion

Conclusions:

NOAEL was considered to be 500 mg/kg bw for P generation and 1000 mg/kg bw for F1 generation when Sprague-Dawley female rats were treated with the test chemical orally by gavage for 10 days of gestation.

Executive summary:

In a teratogenicity study, Sprague-Dawley female rats were treated with test chemical of Octyl acetate (Cas 112-14-1)in the concentration of 0, 100, 500 and 1000 mg/kg/bw/day orally by gavage. Two female rats died in the 1000 mg/kg one each on GDs 10 and 12, respectively. Also, maternal animals in the high-dose group exhibited elevated incidences of alopecia, rales, red nasal discharge and anal-genital staining. Statistically significant and dose-related decrease in mean body weight, and body weight changes were detected in the 1000 mg/kg groups on GDs 9, 12, 16, and 20 were observed at 1000 mg/kg. The effect was most evident during the first several days of dosing, when these animals actually lost weight (GDs 6-9). Statistically significant decrease in mean body weight and body weight changes were observed at several time points at 500 mg/kg as compared with control. These decrease in body weight appeared to occur in an ordered response to dose. Similarly, dose-related decreases in food consumption on GD 6-9, 9-12, and 12- 16 intervals were observed at 500 and 1000 mg/kg as compared with control. The uterine implantation parameters including corpora lutea/dam, implants/litter, resorptions/litter, uterine weight or live fetuses/litter showed no statistically significant or dose-dependent differences between control and any of the treated-groups. Although, a slight increase in the number of resorptions was detected in the 1000 mg/kg group as compared to control, the difference was not significant.In the F1 generation, there was no significant or dose-dependent effects on embryo-fetal lethality or fetal growth for any treatment group.No significant differences or dose-related change were observed on crown rump distance of fetuses were observed as compared to control.The number of litters of at least one malformed fetus and the mean percentage of the litter malformed were significantly elevated in the high-dose group only. External observation revealed only two malformations: one in the 1000 mg/kg group (tail absent) and one in the 500 mg/kg group (micrognathia). Visceral examinations revealed two fetuses with abnormalities only in two fetuses at 1000 mg/kg. All groups exhibited comparably low incidences of malformations (dilated ureters/distended renal pelvises), which are anatomical variations previously observed in historical control fetuses. Fetuses with skeletal malformations were observed in the control, low-dose and high-dose groups at low incidence. In addition, different types of vertebral malformations were observed in four fetuses (four litters) from the high-dose group,but, were not statistically significant as compared to control.In conclusion, the test chemicalduring GD 6-15 at the dose level of 500 mg/ml and 1000 mg/kg resulted in significant maternal toxicity as evidenced by reduction in body weight, body weight gain and food consumption of pregnant female rats. However, the administration of the test chemical at maternally toxic doses of 500 and 1000 mg/kg had no adverse effect on sexual function, fertility and fetus development. The administration of the test chemicalslightly increased the incidence of fetal malformations in rats at 1000 mg/kg, which was seriously toxic for mothers. However, no developmental toxicity was observed at the maternally toxic dose of 500 mg/kg or the maternally non-toxic dose of 100 mg/kg. Some developmental effects produced only at maternally toxic exposure levels which indicates that Octyl acetateis not a selective developmental toxicant in rat and it does not disrupt development without obvious signs of adult toxicity. Hence, the NOAEL for reproductive and developmental toxicity is estimated as 500 mg/kg/bw/day for P0 (parental) generations and 1000 mg/kg/bw/day for F1 generationwhen Sprague-Dawley female rats were orally treated with Octyl acetate for 10 days of gestation under the certain conditions. Maternal toxicity level is 100 mg/kg/bw/day when pregnant female SD rats are orally dosed with the test chemical during gestation.