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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
toxicity to reproduction
Remarks:
other: carcinogenicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, not conducted according to GLP.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981
Reference Type:
publication
Title:
Unnamed
Year:
2000

Materials and methods

Principles of method if other than guideline:
This is a two year oral repeated dose study
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Fyrol FR-2
- Physical state: Clear, viscous fluid
- Purity: 95%
- Storage condition of test material: Room Temperature

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: 53 days
- Weight at study initiation: Males 237g (mean) and ranging from 182 - 271g. Females 154g (mean) and ranging from 126 - 186g.
- Housing: Individually in elevated stainless steel cages
- Diet (e.g. ad libitum): Standard laboratory diet (Purina Lab Chow) ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 21 days (23 March to 13 April 1978)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 2
- Humidity (%): 55 +/- 15
- Air changes (per hr): NK
- Photoperiod (hrs dark / hrs light): 12 hour light/dark cycle


IN-LIFE DATES: From: April 1978 To: April 1980

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Appropriate amounts of test substance (adjusted by most recent weekly body weight and food consumption data) and standard laboratory diet were mixed weekly.
Samples of diets prepared at each dose level were assayed for homogenity and stability of Fyrol FR-2 in feed prior to the initiation of the study. Samples of each diet prepared during the study were saved and samples selected at intervals were assayed for content of Fyrol FR-2. Results not provided, but presented in report no. 78005 (Biodynamics dept. of metabolism and analytical chemistry).
Details on mating procedure:
Not a mating study.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Pubication not available, report no. 78005
Duration of treatment / exposure:
24 Months
Frequency of treatment:
Continuously in the diet, through to the day prior to necropsy.
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0 mg/kg bw/day
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
5 mg/kg bw/day
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
20 mg/kg bw/day
Basis:
nominal in water
Remarks:
Doses / Concentrations:
80 mg/kg bw/day
Basis:
nominal in diet
No. of animals per sex per dose:
60 males and 60 females per dose.
Control animals:
yes, concurrent no treatment
Details on study design:
DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): Standard laboratory diet
- Storage temperature of food: NK

- Dose selection rationale: Doses selected on the basis of results from an 8 week pilot study (Biodynamics report no. 77-1898). Diets were adjusted after each body weight and food consumption measurement to achieve indicated doses.
- Rationale for animal assignment (if not random): More animals than required for the study were purchased and equilibrated. Animals considered unsuitable for the study on the basis of pretest physical and ophthalmoscopic examinations were eliminated prior to random selection for group assignment
Positive control:
No positive control.

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily animals were checked for mortality and gross signs of toxicologic or pharmacologic effects.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Twice pretest, weekly through 13 weeks, biweekly 14 through 26 weeks, monthly thereafter and terminally (after fasting).

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Food consumption was measured pretest, weekly through 14 weeks, biweekly 14 through 26 weeks and monthly thereafter.
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes
Intake calculated from food consumption data, based on nominal concentrations.

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Examinations on all animals conducted at pretest, month 6, month 12, month 18 and month 24.
- Dose groups that were examined: All

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Blood was obtained via venipuncture of the orbital sinus under light anesthesia at month 3, 6 and 18. Blood was obtained from the abdominal aorta at necropsy intervals (months 12 and 24).
- Anaesthetic used for blood collection: Yes (identity) / No / No data
- Animals fasted: Yes
- How many animals: 10/sex at pretest, 10/sex/group at months 3, 6, 12 and 18 and 20/sex/group at month 24.
- Parameters examined: Hemoglobin, hematocrit, erythrocytes, reticulocytes, prothrombin time, partial thromboplastin time, total and differential leukocytes.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Blood was obtained via venipuncture of the orbital sinus under light anesthesia at month 3, 6 and 18. Blood was obtained from the abdominal aorta at necropsy intervals (months 12 and 24).
- Animals fasted: Yes
- How many animals: 10/sex at pretest, 10/sex/group at months 3, 6, 12 and 18 and 20/sex/group at month 24.
- Parameters examined: Serum glutamic pyruvic transaminase, alkaline phosphataase, blood urea nitrogen, fasting glucose, total protein, albumin, globulin and A/G ratio.

URINALYSIS: Yes
- Time schedule for collection of urine: Pretest, months 3, 6, 12, 18 and 24.
- Metabolism cages used for collection of urine: No data
- Animals fasted: Yes
- Parameters examined: Gross appearance, specific gravity, pH, protein, glucose, ketones, bilirubin, occult blood and microscopic analysis.

NEUROBEHAVIOURAL EXAMINATION: No

POSTMORTEM: Yes
- Time schedule: Complete gross postmortem examination conducted if animals died spontaneously or were killed in a moribund condition, at month 12 and month 24.
- How many animals: 10/sex/group at month 12 and all survivors at month 24.
- Organs weight and organ/body weight ratios collected: Brain, pituitary, adrenals, testes, heart, thyroid, spleen, kidneys and liver.

Oestrous cyclicity (parental animals):
Fertility parameters not measured.
Sperm parameters (parental animals):
Fertility parameters not measured.
Litter observations:
No Offspring
Postmortem examinations (parental animals):
as above
Postmortem examinations (offspring):
No Offspring

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
effects observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Other effects:
effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
not examined

Details on results (P0)

Mortality
Mortality rates in all groups were low during the first 12 months of the study with no remarkable difference in incidence between control groups and groups receiving TDCP. Mortality remained low in most groups from 12 through 17 months; however a slight increase in the number of deaths in the high dose males over that in control males was apparent during this interval. After month 17, the mortality rate increased in all groups and remained high until the end of the study (this can be expected in ageing animals). Total mortality in low- and mid-dose males and in all TDCP-treated females was considered comparable to that of the controls. Significantly greater mortality (p<0.05) was recorded for high dose males, (38/60 animals died in highest treatment group compared to 26/60 in controls).

Body Weight
There was a clear adverse effect on body weight in the 80 mg/kg/day groups, throughout the study, with body weights at termination >20 % lower than control. Slight decreases (most differences did not exceed 5 %) in male body weights in the 20 mg/kg/day at some intervals of the study may also have related to treatment. Food consumption for controls and high dose animals was generally comparable except for slight increases in values for the high dose groups during the last few months of the study.

Gross pathology
Gross observations noted in the male reproductive tract in the mid and high doses included various discolourations, masses/nodules, enlargement and flaccidity in the testes as well as small seminal vesicles. The corresponding testes weights were not significantly higher than control males.

Histopathology
Histological changes were also noted in the testes, the epididymides and the seminal vesicles both in control animals and all treatment groups.
In the testes, germinal epithelial atrophy with associated oligospermia was noted in controls and all treated groups at both 12 months and 24 months. At 12 months, there was an increase above control values for the high dose group (statistical analysis was not performed on this data) and at 24 months there was an increase above control values in the mid and high dose animals. The incidence of sperm stasis was increased above control values (approx 11 %) at the mid and high doses (approx 23 % and 31 %, respectively) at 24 months. Again, statistical analysis was not performed on this data. There was also an increase in the incidence of amorphous eosinophilic material in the tubular lumens and periarteritis nodosa were observed in all treated animals at 24 months. These effects on sperm stasis, the incidence of amorphous eosinophilic material and periarteritis nodosa in the testes were only reported to be observed at 24 months. The report indicated that the testes were “suitable for evaluation” at 12 months, although no result was presented in the report for this time point, so it can only be assumed that the testis were evaluated for these effects at 12 months, and that no effects were observed.

In the epididymides, oligospermia was noted in one high dose animal at 12 months. There was none noted in any control animals and the epididymides from the low and mid dose animals were not evaluated, apart from one unscheduled mid dose animal. Oligospermia was also noted in controls and all treated groups at 24 months, with a greater occurrence in the high dose group. 26 % of the control group showed oligospermia at 24 months, with 28 %, 54 % and 79 % displaying it at the low, mid and high doses, respectively. Degenerated seminal product was observed in all animals at 24 months (this was not examined in the low and mid doses at 12 months; it can only be presumed that it was examined at the high dose at 12 months, and did not occur), with the greatest increase in the high-dose group. 19 % of the control group showed degenerated seminal product, with 22 %, 23 % and 50 % displaying it at the low, mid and high doses, respectively.

In the seminal vesicles, secretory product was decreased in the seminal vesicles of one high dose animal at 12 months (not noted in any control animals and the effect was not examined in the low and mid doses at 12 months) and in all treated animals at 24 months. At 24 months, 2 % of control animals displayed decreased secretory product, compared with 84 %, 89 % and 52 % of the low, mid and high dose animals, respectively. Atrophy of the seminal vesicles was observed in all treated animals at 24 months (30 %, 31 % and 23 % of the low, mid and high dose animals, respectively), but not in any of the control animals. Only the control and high dose12 month animals were examined for atrophy of the seminal vesicles; no indication was given on an effect observed in the high dose animals.

Effect levels (P0)

Dose descriptor:
LOAEL
Effect level:
5 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: Based on the hyperplasia of the convuluted tubule epithelium with increased incidences observed in all treated male animals and high-dose females at 24 months.

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

Effect levels (F1)

Remarks on result:
not measured/tested

Overall reproductive toxicity

Reproductive effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Effects were noted in the testes, epididymis and seminal vesicles in all animals at 24 months, with a trend for higher incidence in the treated groups.
An increase in interstitial cell tumours of the testes in the mid and high dose males at the 12 and 24 months was observed in this study (as indicated in the carcinogenicity study).
No evaluation of the female reproductive system was included in the 2-year carcinogenicity study with TDCP.