1-chlorobutane

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Nihon Bioreseach Center Inc., Hashima Laboratory, Hashima, Japan

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Japan
- Age at study initiation: 8 weeks
- Weight at study initiation: females: ~230 g; males: ~340 g
- Housing: stainless steel and plastic cages
- Diet (ad libitum): solid pellets (CRF-1, Oriental Yeast Co. Ltd.)
- Water (ad libitum): tap water
- Acclimation period: 11 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 40-70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

VEHICLE
- Concentration in vehicle: 0, 0.048, 0.24, 1.2, 6%
- Amount of vehicle (if gavage): max. 5 mL/kg/bw
- Lot/batch no.: 5233 and 8250

Details on mating procedure:

Mating was performed in hanging stainless steel cages

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Stability of test solutions were confirmed 1 and 3 hours after preparation of doses.

Duration of treatment / exposure:

males: 49 days
females: 41-46 days (from 14 days before mating to day 3 of lactation)

Frequency of treatment:

once daily

Details on study schedule:

- No mating of F1 generation (study design according to OECD Guideline 421, no mating of F1 generation foreseen)

Remarks:

Doses / Concentrations:
0, 2.4, 12, 60, 300 mg/kg bw/d
Basis:
nominal conc.

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Preliminary study with male rats was conducted. Dose levels: 0, 10, 30, 100, 300, 1000 mg/kg bw/d
Within 5 days all animals of the top dose died. Salivation was observed 3 days after treatment in group 300 mg/kg bw/d, 7 days after treatment in group 100 mg/kg bw/d. Actual concentrations were selected on the basis of these results.

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations: general conditions and mortality

BODY WEIGHT: Yes
- Time schedule for examinations: twice a week

FOOD CONSUMPTION: Yes
- twice a week (converted to a daily dose measured over two consecutive days)

POST-MORTEM EXAMINATIONS: Yes
- Organs examined: testes, epididymes, ovaries, stomach, small intestine

OTHER:
reproductive indices

Oestrous cyclicity (parental animals):

numbers of times in estrus before and during administration, number of corpora lutea

Sperm parameters (parental animals):

Parameters examined in P male parental generations:
testis weight, epididymis weight

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals on day 50
- Maternal animals: All surviving animals

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring was sacrificed at 4 days of age.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

Statistics:

Bartlett-test, Dunnet-test, Scheffe-test, χ2-test

Reproductive indices:

copulation index, fertility index, gestation index, delivery index

Offspring viability indices:

birth index, viability index

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
males:
- salivation in all dose groups

females:
- salivation: before and during mating in animals receiving 60 and 300 mg/kg bw/d, during pregnancy in animals receiving 12 mg/kg bw/d - 300 mg/kg bw/d and during lactation in highest dose females (300 mg/kg bw/d)
- One dam died on day 22 of pregnancy and one dam died on day 4 of lactation in the 300 mg/kg bw/d group.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
- statistically significant suppressed body weight gain in males and females of the 300 mg/kg bw/d dose group
- reduced food consumption in males and females receiving 300 mg/kg bw/d

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
- no effect on estrous cycle

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
- All 12 pairs of each dose group copulated successfully (copulation index 100%).
- All females except one female in the 60 mg/kg bw/d dose group became pregnant (fertility index: 0, 2.4, 12, 300 mg/kg bw/d 100%; 60 mg/kg bw/d 91.7%).
-The gestation index was 100% for animals receiving 0 - 60 mg/kg bw/d and for the 300 mg/kg bw/d group 91.7% because of the death of one dam on day 22 of pregnancy.

ORGAN WEIGHTS (PARENTAL ANIMALS)
- There are statistically significant higher relative testis and statistically not significant higher relative epididymis weights (300 mg/kg bw/d). These increases may be due to the reduced body weights because the absolute testis and epididymides weights were not affected.

GROSS PATHOLOGY (PARENTAL ANIMALS)
- surviving females on day 4 of lactation: 12/12 controls, 12/12 animals of 2.4 mg/kg bw/day, 11/11 animals of 12 mg/kg bw/day, 10/10 animals of 60 mg/kg bw/day and 5/9 animals of 300 mg/kg bw/day did not show necropsy findings. At a dose of 300 mg/kg bw/day the following effects were observed: in two of 9 animals white glandular mucosa of the stomach, in 1 of 9 animals each dark red spots, black spots and edema in the glandular mucosa of the stomach, in 1 of 9 animals black discoloration of the small intestine

- males: no necropsy findings

HISTOPATHOLOGY (PARENTAL ANIMALS)
males testis:
- moderate degeneration of seminiferous tubules with giant cells (1/12 animals at 300 mg/kg bw/d)
males epididymis:
- arteritis in capsule (1/12 animals in the control group)
- slight interstitial cell infiltration (1/12 animals at 300 mg/kg bw/d)
- mild hypospermia in epididymis (1/12 animals at 300 mg/kg bw/d)
The effects observed in histopathology in male reproductive organs occured spontaneous and were not considered compound-related.

females: histopathological examinations of the ovary in the other dose groups of n-butyl chloride except 300 mg/kg bw/day group were not carried out. No remarkable changes were recognized in the ovary.

Dose descriptor:

NOAEL

Effect level:

60 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: systemic effects (reduced body weights, food consumption at the LOAEL of 300 mg/kg bw/day)

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects on fertility in highest dose tested

screening study: no data for toxicity on reproduction/fertility of F1 offspring provided
for details on developmental toxicity of F1 offspring see 7.8.2 MHW_Japan_1993

Reproductive effects observed:

not specified

Number of times in estrus of female rats (P)

Group [mg/kg bw/d]	Control	n-butyl chloride
	0	2.4	12	60	300
Number of females	12	12	12	12	12
Number of times in estrus before a administration (7 days)	1.8 +/- 0.5	1.7 +/- 0.5	1.8 +/- 0.4	1.7 +/- 0.5	1.7 +/- 0.5
Number of times in estrus during administration (14 days)	3.2 +/- 0.4	3.3 +/- 0.5	3.3 +/- 0.5	3.3 +/- 0.5	3.3 +/- 0.5

 

 

Organ weight of male rats (P) after mating period

Group [mg/kg bw/d]	Control	n-butyl chloride
	0	2.4	12	60	300
Number of animals	12	12	12	12	12
Absolute body weight [g]	483.2 +/- 35.6	496.2 +/- 24.6	481.6 +/- 26.7	475.7 +/- 25.6	432.4 +/- 21.5**
Absolute testes weight [g]	3.265 +/- 0.196	3.272 +/- 0.212	3.356 +/- 0.316	3.369 +/- 0.293	3.243 +/- 0.265
Relative testes weight [g]	0.677 +/- 0.058	0.663 +/- 0.05	0.697 +/- 0.067	0.711 +/- 0.083	0.752 +/- 0.074*
Absolute epididymides weight [g]	1.263 +/- 0.128	1.225 +/- 0.091	1.274 +/- 0.077	1.215 +/- 0.097	1.175 +/- 0.095
Relative epididymides weight [g]	0.264 +/- 0.032	0.248 +/- 0.027	0.264 +/- 0.020	0.257 +/- 0.025	0.272 +/- 0.025

*: P < 0.05

**: P < 0.01

Effect on fertility: via oral route

Dose descriptor:

NOAEL

300 mg/kg bw/day

Additional information

There is no two-generation reproduction study available. However, a reproduction / developmental toxicity screening test and histopathological data on sexual organs from a carcinogenicity study and a repeated dose 90-day oral toxicity study were used for assessment of toxicity to reproduction.

 

In a reproduction / developmental toxicity screening test according to OECD Guideline 421 Crj:CD rats received 2.4, 12, 60 and 300 mg/kg bw/day 1-chlorobutane by gavage. Males were exposed for 49 days including 14 days before mating and females received 1-chlorobutane from 14 days before mating to day 3 of lactation. In the highest dose group depression of body weight gain and reduced food consumption was observed. In addition 1/12 females died on day 22 of pregnancy and one dam on day 4 of lactation in the 300 mg/kg bw/day dose group. Males of all dose groups and females receiving 12 mg/kg bw/day and higher doses showed salivation. There were no significant changes of absolute organ weights, nor in gross and histopathological findings. The results observed in mating, fertility and estrous cycle did not reveal any effects attributable to the administration of 1-chlorobutane. The fertility index was 100% in all dose groups, except in the 60 mg/kg bw/day (fetility index: 91.7%) group in which 1/12 females was not pregnant. Observation of delivery showed that all gestation animals delivered pups normally (MHW Japan, 1993). The NOAEL for systemic effects in parental animals was 60 mg/kg bw/day and the NOAEL for fertility (P) was 300 mg/kg bw/day.

In a carcinogenicity study (NTP, 1986) in F344/N rats and B6C3F1 mice no compound-related reproductive effects on sexual organs (seminal vesicles/prostata/testes or ovaries/uterus) were found during histopathological examination of animals receiving 60 or 120 mg/kg bw/day and 250, 500 and 1000 mg/kg bw/day 5 days per week for 103 weeks, respectively. Thus, no evidence for effects on fertility is considered in concentrations of 120 mg/kg bw/day for rats, 500 mg/kg bw/day for female mice and 1000 mg/kg bw/day for male mice, respectively.

In a subchronic study (NTP, 1986) F344/N rats and B6C3F1 mice were administered (gavage) 0, 30, 60, 120, 250 and 500 mg/kg bw/d and 0, 60, 120, 250, 500 and 1000 mg/kg bw/day 1-chlorobutane 5 days/week for 90 days. No gross pathological nor histopathological findings on sexual organs (prostate/testes or ovaries/uterus) were observed at the highsest dose tested. Thus no evidence for effects on fertility due to lack of effects on sexual organs is considered in a concentration of 500 mg/kg bw/day for rats and 1000 mg/kg bw/day for mice.

 

Taken together in a weight of evidence approach, the data indicate that 1-chlorobutane has no effects on fertility.

 

Short description of key information:
NOAEL (fertility, rat) = 300 mg/kg bw/day (MHW Japan, 1993)

Effects on developmental toxicity

Description of key information

NOAEL (maternal toxicity, rat) = 60 mg/kg bw/day due to reduced body weights and food consumption at the LOAEL of 300 mg/kg bw/day (MHW Japan, 1993)
NOAEL (developmental toxicity, rat) = 2.4 mg/kg bw/day due to a lack of maternal care (MHW Japan, 1993)
NOAEL (teratogenicity, rat) = 300 mg/kg bw/day, highest dose level tested (MHW Japan, 1993)

Additional information

Developmental toxicity of 1-chlorobutane was studied in Crj:CD rats at doses of 2.4, 12, 60 and 300 mg/kg bw/day by gavage according OECD Guideline 421 (reproduction / developmental toxicity screening test). Males were exposed for 49 days including 14 days before mating and females received 1 -chlorobutane from 14 days before mating to day 3 of lactation. The external examination of pups revealed a statistically not significant depression of viability index and body weight gain in the 300 mg/kg bw/day group due to maternal toxicity. One dam of the 300 mg/kg bw/day died on day 4 of lacatation and lack of pup care was observed in another dam, that showed decreased food consumption and body weight loss. Lack of pup care behaviour (i.e. lack of lactating and nesting) was also observed in one female each in the 12 mg/kg bw/day dose group and 60 mg/kg bw/day, resulting in death of all pups. No remarkable changes in necropsy findings of the pups from all dose groups at day 4 were observed, confirming that the decrease in viablity of pups at doses > 2.4 mg/kg bw/day is due to maternal toxicity. The NOAEL was considered to be 60 mg/kg bw/day for maternal toxicity based on reduced body weights and food consumption at the LOAEL of 300 mg/kg bw/day and 2.4 mg/kg bw/d for developmental toxicity based on the increased mortality of pups due to a lack of maternal care. On the basis of no remarkable changes in pup necropsy the NOAEL for teratogenicity (MHW Japan,1993) was considered to be 300 mg/kg bw/day.

In another reproduction toxicity study by Leonskaya (1980), reported as short abstract from secondary source (Rudnev et al., 1979; Val. 4), female Wistar rats were gavaged daily with 1 -chlorobutane at concentrations of 0.72, 110 or 733 mg/kg in sunflower oil during the first 19 days of pregnancy and were evaluated for embryotoxic and teratogenic effects. Embryo mortality and the number of foetuses with internal organ hemorrhage was increased in the 733 mg/kg bw/day dose group. In this high dose group pronounced toxic effects were observed. The cranio-caudal index (ratio of the conduction velocities in the forelimb and hindlimb nerves) was significantly elevated in dams receiving 733 mg/kg bw/day. No effects on embryo mortality or bleedings in organs of fetuses were seen in the lower dose groups. Progeny of the dosed females were observed for 30 days following birth. No compound-related effects were observed in mortality, body weight change, time of appearance of body hair or opening of eyes. The offspring were crossbred (within dose group) and subsequently examined. 1 -Chlorobutane also increased embryo mortality in the second generation in the highest dose group.

In summary, it is concluded that the observed developmental and hazardous effects on embryogenesis in large doses are due to toxic effects on dams.

Justification for classification or non-classification

The available data is conclusive but not sufficient for classification according to DSD (67/548/EEC) and CLP (1272/2008/EC).