3,5,5-trimethylcyclohex-2-enone

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

There is no evidence indicating that the test substance interferes adversely with the reproduction. No changes were observed in pregnancy rates, litter sizes, pup abnormalities or in histopathological examinations of the reproductive organs after long-term studies.

Link to relevant study records

Reference

Endpoint:

one-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Limitations: only one dose tested, small group size

Qualifier:

no guideline followed

Principles of method if other than guideline:

In a limited one generation study, rats were exposed to the test substance in air. After three months of exposure, exposed males were mated with control and exposed females, control males were mated with control and exposed females. Exposure of females continued throughout gestation and they were allowed to deliver.

GLP compliance:

not specified

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: approximately 140 g

Route of administration:

inhalation

Type of inhalation exposure (if applicable):

not specified

Vehicle:

air

Details on mating procedure:

after three months of exposure overnight mating of
5 exposed males with 5 exposed females
5 exposed males with 5 control females
5 control males with 5 exposed females
5 control males with 5 control females
next morning exposure continued for exposed animals (females until littering)

No information on mating success.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Exposure period: 6 hours/day
Premating exposure period (males): 3 months
Premating exposure period (females): 3 months
Duration of test: females: 4 months; males: 6 months

Frequency of treatment:

5 days/week

Dose / conc.:

500 ppm

Remarks:

= 2873 mg/m3 (saturation)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Parental animals: Observations and examinations:

behaviour, body weight development, mortality

Litter observations:

number and vitality

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Irritation of eyes and nose (in exposed animals)

Mortality:

mortality observed, treatment-related

Description (incidence):

No mortalities in control groups.
1/10 of exposed females and 2/10 of exposed males died.

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Slight to medium congestion in lungs with similar intensity in exposed and control; granular state and clarification of liver cytoplasma with similar intensity in exposed and control.

Histopathological findings: neoplastic:

no effects observed

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

Dose descriptor:

LOAEC

Remarks:

general toxicity

Effect level:

500 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

mortality

Remarks on result:

other: corresponds to 2873 mg/m³

Dose descriptor:

NOAEC

Remarks:

fertility

Effect level:

500 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Remarks on result:

other: corresponds to 2873 mg/m³

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Anogenital distance (AGD):

not examined

Nipple retention in male pups:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Behaviour (functional findings):

no effects observed

Developmental immunotoxicity:

not examined

Dose descriptor:

NOAEC

Remarks:

= 2873 mg/m³

Generation:

F1

Effect level:

500 ppm

Remarks on result:

other: no adverse effects observed

Critical effects observed:

no

Reproductive effects observed:

not specified

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

2 873 mg/m³

Study duration:

subchronic

Experimental exposure time per week (hours/week):

30

Species:

rat

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In a limited one generation study, 10 male and 10 female Wistar rats were exposed to 2872 mg/m3 (500 ppm) test substance in air (Dutertre-Catella, 1976). After three months of exposure, 5 exposed males each were mated with 5 control and 5 exposed females, 5 control males each were mated with 5 control and 5 exposed females. Exposure of females continued throughout gestation and they were allowed to deliver. Treatment with the test substance did not influence pregnancy rates and litter sizes nor were there any abnormalities observed in the pups.

The histological examinations of the reproductive organs of male and female mice and rats (mammary gland, seminal vesicle, prostate/testis or ovary/uterus) treated orally with up to 1000 mg test substance/kg bw for 13 weeks did not reveal any adverse effects after macroscopic and microscopic examination (Bucher, 1986). In a 90-day study with male and female beagle dogs (4 animals/dose/sex were administered up to 150 mg test substance per kg bw per day) no changes were reported either after histopathological examination of testes, prostate, seminal vesicles or ovary, uterus, mammary gland, respectively (Rohm & Haas, 1972).

Effects on developmental toxicity

Description of key information

In an inhalation teratogenicity study, the NOAEL for maternal toxicity was 289 mg/m³ (based on a reduction in body weight gain and food consumption).
The test substance was neither embryotoxic nor teratogenic up to the highest test concentration of 664 mg/m³.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Fischer 344

Route of administration:

inhalation

Type of inhalation exposure (if applicable):

whole body

Vehicle:

unchanged (no vehicle)

Details on exposure:

Vehicle: no vehicle.
Concentrations: 0, 25, 50, 115 ppm (corresponds to 0.144, 0.289, 0.664 mg/L; low mid and high dose).
Type or preparation of particles: vapor.
Pregnant rats were dosed on days 6 through 15 of gestation (G).

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

- Impregnation procedure: cohoused
- Length of cohabitation: until confirmed to have mated
- Proof of pregnancy: vaginal plug or sperm in vaginal smear

Duration of treatment / exposure:

gestation day 6 - gestation day 15

Frequency of treatment:

6 hours/day

Duration of test:

Section on gestation day 20

Dose / conc.:

25 ppm

Remarks:

corresponds to 0.144 mg/L

Dose / conc.:

50 ppm

Remarks:

corresponds to 0.289 mg/L

Dose / conc.:

115 ppm

Remarks:

corresponds to 0.664 mg/L

No. of animals per sex per dose:

22 mated female rats per dose level

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale: based on results of preliminary study

Maternal examinations:

PARAMETERS ASSESSED DURING STUDY
Body weight gain: each 3rd day.

Food consumption: 3 day intervals.

Clinical observations: each 3rd day.

Ovaries and uterine content:

PARAMETERS ASSESSED DURING STUDY
Examination of uterine content: identified as live fetuses, dead fetuses, late resorptions, and early resorptions at the end of the study (day 20 of gestation). The uterus of each animal was stained in 10 % aqueous ammonium sulfide and further examined for confirmation of implantation sites. Corpora lutea were counted.

Fetal examinations:

PARAMETERS ASSESSED DURING STUDY
Examination of fetuses: Live and dead fetuses were weighed, examined externally for gross abnormalities, and crown-rump distances were determined.
Further examinations: skeletal malformations and ossification variations.

Statistics:

Bartlett's test of homogeneity of variance: body weight, body weight change, food consumption, number of implantation sites, ratio of live fetuses to implantation sites, ratios of resorptions to implant sites, malformations per litter. Kruskal-Wallis test if variances were not equivalent. Standard nested analysis of variance for fetal weights.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

dose related increases in alopecia and staining of the cervical and anogenital areas

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

reduced on gestation days 12 (-6.1 %) and 15 (-6.8 %) in high dose group

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

reduced food consumption in high dose group (days 6-20 and 0-20)

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Number of abortions:

not examined

Pre- and post-implantation loss:

not examined

Total litter losses by resorption:

no effects observed

Early or late resorptions:

not examined

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

No statistically significant differences between treated and control groups: Number of resorptions, number of implantations, number of corpora lutea, duration of pregnancy.

Dose descriptor:

NOAEC

Effect level:

0.289 mg/L air

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Abnormalities:

no effects observed

Fetal body weight changes:

not examined

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

not examined

External malformations:

no effects observed

Skeletal malformations:

no effects observed

Visceral malformations:

no effects observed

Details on embryotoxic / teratogenic effects:

No statistically significant differences between treated and control groups:
Litter size and weights, number viable, sex ratio, grossly visible abnormalities, external abnormalities, soft tissue abnormalities, skeletal abnormalities.

During the conduct of the study there was one instance of exencephaly noted in a rat fetus. Based on the observations made in this study the authors do not believe that this anomaly was related to the test material.

Dose descriptor:

NOAEC

Effect level:

0.664 mg/L air

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed up to and including the highest tested concentration

Abnormalities:

no effects observed

Developmental effects observed:

no

Conclusions:

The test material elicited a clinical effect in the pregnant dams in the form of decreased food consumption, lower body weights and dose related increases in alopecia and staining of the cervical and anogenital areas.
Within the framework of the dose levels and test methods used, the test material was not teratogenic or fetotoxic.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

289 mg/m³

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Pregnant Fischer 344 rats and CD-1 mice were exposed on days 6 through 15 of gestation to test substance concentrations of 144, 289, or 664 mg/m³ (22 animals per dose level). There was a significant reduction in food consumption in rats and mice of the highest dose group. Body weight was reduced in rats (gestation day 12: -6.1%; gestation day 15: -6.8%) and mice (gestation day 18, corrected for uterine weight: -5.6%) of the highest dose group. In rats, a dose related increase in alopecia was observed, as well as a discoloration of the cervical and anogenital region. In mice, this effect was observed only in one animal of the high dose group. Adverse effects on the fetuses were not observed (Exxon, 1984).

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for reproductive toxicity under Regulation (EC) No. 1272/2008, as amended for the 14th time in Regulation (EU) 2020/217.