4-vinylcyclohexene

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: Toxicity to reproductive organs; fertility

Type of information:

other: publication

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Long-term ovarian and gonadotropin changes in mice exposed to 4-vinylcyclohexene

Author:

Hooser SB, Douds DP, DeMerell DG, Hoyer PB and Sipes IG

Year:

1994

Bibliographic source:

Reprod. Toxicol., 08, 315-323

Materials and methods

Principles of method if other than guideline:

method described in the publication

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

4-vinylcyclohexene

EC Number:

202-848-9

EC Name:

4-vinylcyclohexene

Cas Number:

100-40-3

Molecular formula:

C8H12

IUPAC Name:

4-ethenylcyclohex-1-ene

Details on test material:

VCH 99% purity from Aldrich Chemical Co (Milwaukee); vehicle from Sigma Chemical Co. (St. Louis) (no information about purity)

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

female

Details on test animals or test system and environmental conditions:

21 day old mice purchased from Harlan Sprague Dawley Inc. Indianapolis)
-housed 5 per cage
-free access to food and water
-12h light/dark cycle
-acclimated 7 days before use

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

other: sesame seed oil

Details on exposure:

test dose: 800 mg/kg VCH in sesame seed oil
control: sesame seed oil 2.5 ml/kg
animal dosing starts at 28 days age

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

30 days

Frequency of treatment:

daily intraperitoneal injections

Details on study schedule:

-animals were weighted daily in the first 30 days and then weekly until day 120
-animal groups (n=10 treated and control each) were killed by CO2 inhalation at 30, 60, 120, 240 and 360 days on the first day they were determined to be in diestrus (determined by vaginal cytology)
-vaginal smears performed for first 120 days and then for one week prior necropsy of 240 and 360 day group
-blood was collected
-plasma was prepared and frozen for FSH determination
-ovaries were removed, weighted and fixed; histopathological sections 4-6 µm were made (staining: HE)
-counting of small and growing prenatal follicles were counted acc. to Method of Pedersen and Peters
-Serum FSH measured by radioimmunoassay as described by Beamer et al.
-plasma androstendione concentrations were determined with an kit using antibodies (Diagnostic Products Corporation, Los Angeles)

Doses / concentrations

Remarks:

Doses / Concentrations:
800 mg/kg
Basis:
other: i.p.

No. of animals per sex per dose:

5 groups (each 10 females) treated with substance and 5 groups (each 10 females) treated with vehicle alone

Control animals:

yes, concurrent vehicle

Details on study design:

see "Details on study schedule"

Positive control:

no

Examinations

Parental animals: Observations and examinations:

see "Details on study schedule"

Oestrous cyclicity (parental animals):

see "Details on study schedule"

Sperm parameters (parental animals):

not applicable

Litter observations:

not applicable

Postmortem examinations (parental animals):

see "Details on study schedule"

Postmortem examinations (offspring):

not applicable

Statistics:

Data analysis: data analyzed by Number Cruncher Statistical system 5.0; ANOVA used for multiple comarisons (in case of significant differencesNewman-Kuel range test was used with level of significance P<0.05)

Reproductive indices:

see "Details on study schedule"

Offspring viability indices:

not applicable

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

- number of follicles reduced in treated mice compared to control mice; number of oocytes reduced in in small (to 11% of control) and growing prenatal follicles (to 22% of control) reduced

Other effects:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

effects observed, treatment-related

Description (incidence and severity):

irregular (prolonged diestrus) estrus cycle in both groups for the first several weeks; day 60, 120: no significant differences between VCH treated animals (7.0+-0.5) an control (6.5+-0.5) regarding number of estrus cycles per 30 days

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

Details on results (P0)

day 240:
-very few widely scattered oocytes in small and growing follicles still present
-ovaries had small, irregularly shaped nests of large round to polyhedral cells with abundant, pale cytoplasm and large round to oval nuclei
-day 240 increase of FSH concentration (130% above control)
-control and treated animals demonstrated estrus cyclicity
day 360:
-no oocytes at any stage observed in treated mice
-foci of cells scattered throughout the ovarian cortices and increased in size
-androstenedione significantly decreased
-day 360 increase of FSH concentration (160% above control)
-control mice cyclic but treated mice acyclic (determined by vaginal cytology)

Effect levels (P0)

Key result

Dose descriptor:

NOAEL

Effect level:

<= 800 mg/kg bw/day

Sex:

female

Basis for effect level:

other: Only one dose (800 mg/kg/d) was used that showed toxic effects. Hence no NOAEL or LOAEL can be derived.

Remarks on result:

not determinable

Remarks:

no NOAEL identified

Results: F1 generation

General toxicity (F1)

Clinical signs:

not examined

Mortality / viability:

not examined

Body weight and weight changes:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

Details on results (F1)

not applicable

Effect levels (F1)

Key result

Remarks on result:

not measured/tested

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Treatmend with VCH for a time period of 30 days produced irreversible ovarian failure in mice under the condition of this study.

Executive summary:

After exposure of mice to VCH appr. 90% of oocytes in small follicles and 80% of the oocytes in growing prenatal follicles are destroyed after 30 days of treatment. During the course of the study the numbers of these follicles containing oocytes continued to decrease. By 360 days VCH trated mice (treatment for 30 days) showed loss of cyclicity. At this time complete oocyte depletion of ovaries and markedly reduced ovarian weights had occured.