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Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Remarks:
one generation reproduction study preceeds OECD Guidelines
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Ten male and 20 female sexually mature rats per groups were exposed to the following levels of 2,4,7,9-Tetramethyl-5-decyne-4,7-diol.

1. Low Dose: 500 mg/kg/d
2. Mid Dose: 1,000 mg/kg/d
3. High Dose: 2,000 mg/kg/d

The animals were mated and the newborn raised to weanling age.
The weanlings were randomized to their respective groups according to our Standard Operating Procedure and carried on the same levels to the termination of the experiment.
Body weight and feed consumption data as well as several reproductive parameters were taken from the Fo rats.
Body weight and feed consumption data were taken weekly from the Fla rats.
Certain hematological and urine analytical parameters were performed on five male and five female Fla rats per group after 45 days and after 91 days.
Certain clinical chemistry parameters were performed on five male and five female Fla rats per group after 91 days on test.
Gross necropsy was performed on all rats .
Organ weights and organ-to-body weight ratios were done on ten male and ten female Fla rats per group.
Complete histopathology was done on ten male and ten female rats from the high dose and control group while the major organs were examined histopathologically from all remaining survivors.
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: waxy solid
Details on test material:
Lot Number: 2910-109
Purity: 100 %

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Mass.
- Acclimation period: four weeks
- Housing: The animals were housed individually during quarantine in steel wire mesh suspended cages in a room by themselves with a constant temperature of 73° +/- 3° F (equal to 23° +/- 2° C), with a constant humidity of approximately 40 % to 70 % and with 100 % fresh air make-up, approximately eight to ten complete air changes per hour.
- Diet, Water: Feed and water were provided ad libitum.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23° +/- 2° C
- Humidity (%): 40 % to 70 %
- Air changes (per hr): 8 - 10

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION

- Rate of preparation of diet (frequency):
The test diets were prepared weekly by the respective study coordinator, based on the mean body weight and the mean feed consumption during the second previous week.

- Mixing appropriate amounts with (Type of food):
The basic feed supply for the duration of the experiment was "Charles River 19RF, Rat, Mouse, Hamster Meal" manufactured by Agway of syracuse, New York. Test diets were prepared weekly by mixing the appropriate amount of test item with the appropriate amount of basic diet in a three cubic feet Patterson Kelley twin shell mixer, tumbling at a rate of 40 tumples per minute around a high speed coaxial mixing bar equipped with discs bearing slanted blades rotating at the rate of 2,000 PPM. Fresh diets were prepared weekly. Feed consumption was measured by weighing the feed containers full of feed at the beginning of the week (full weight) and the same feed containers with the remaining feed at the end of the week (empty weight). All feed remaining at the end of the week was disposed of.

Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
91 days
Doses / concentrationsopen allclose all
Dose / conc.:
500 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
Dose / conc.:
2 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
10 male
20 female
Control animals:
yes
Details on study design:
Ten male and twenty female sexually mature rats were randomly assigned to each group.  Males were sacrificed following the 20th day of breeding and females were sacrificed when their litters were weaned at 21 days of age.  Animals were fed their respective diets from the start of cohabitation until their scheduled sacrifice.  
The weanlings were randomized within their respective groups and carried on the same dose levels as their parents for 91 days.  Test diets were prepared weekly. Analytical monitoring of the test diets was performed.  Statistical analysis of the body weight, food consumption, clinical chemistry, and hematology data was performed using the Student’s t-test.

Examinations

Observations and examinations performed and frequency:
Males were sacrificed following the 20th day of breeding and females were sacrificed when their litters were weaned at 21 days of age.  Animals were fed their respective diets from the start of cohabitation until their scheduled sacrifice.  
The weanlings were randomized within their respective groups and carried on the same dose levels as their parents for 91 days.  Test diets were prepared weekly. Analytical monitoring of the test diets was performed.  Statistical analysis of the body weight, food consumption, clinical chemistry, and hematology data was performed using the Student’s t-test.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Description (incidence and severity):
No rats expired in this phase of the experiment
Mortality:
no mortality observed
Description (incidence):
No rats expired in this phase of the experiment
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Only one pertinent finding: The mean body weight of the high dose female group after weaning its young was significantly lower than the corresponding control.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
The feed consumption of the high dose female group after weaning its young was significantly lower than the control. There was no other pertinent findings.
Food efficiency:
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not specified
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Description (incidence and severity):
No gross abnormalties were observed in any of the F0 parents, either male or female.
Histopathological findings: non-neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): All rats survived for the duration of the study. No abnormal clinical signs were observed in any of the rats, either test or control, during the entire study period.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS): Only one pertinent finding: The mean body weight of the high dose female group after weaning its young was significantly lower than the corresponding control.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS): The feed consumption of the high dose female group after weaning its young was significantly lower than the control. There was no other pertinent findings.


GROSS PATHOLOGY (PARENTAL ANIMALS): No gross abnormalities were observed in any of the Fo parents, either male or female.

Hematological Values at 45 Days:

RBC: The mean total RBC counts in the mid dose and the high dose male test groups were significantly Lower than the control.
All values however, mean as well as individual, were within our normal range.
HGB: The mean hemoglobin values of the mid dose and high dose male rats were significantly lower than the control, while the same value was higher than the control in the high dose female rats.
All values, however, mean as well as individual, were within our established normal range.
HMCT: The mean HMCT values for the low and high dose group of male rats were statistically lower than the control, while the mean HMCT value for the high dose female group was statistically higher than the control. All values, however, mean as well as individual, were within normal range.
WBC: All total WBC counts, mean as well as individual, were within our normal range.
WBC Diff: All rats exanined displayed normal differential counts.
Plat. Est : The platelets of all rats examined were deemed to have been adequate.

Hematological Values at 92 Days:

RBC: All total RBC counts, mean as well as individual, were within normal range.
HGB: All HGB values, mean as well as individual, except one were within normal range; high dose female rat #I122 had a HGB of 11.6 g/dl; histologically this rat exhibited mild pulmonary lymphocytosis.
HMCT: All HMCT values, mean as well as individual, were within normal range.
WBC: The mean total WBC counts of the low and high dose groups were significantly higher than the control groups. All total WBC counts, however, mean as well as individual, were within normal range.
WBC Diff: All rats examined displayed a normal differential counts.
Plat.-Est.: The platele testimate of all rats examined were deemed to have been adequate.

Urinalysis at 45 and 91 days: There were no significant differences between the test and control groups, male or female, in any urinalysis parameters.

Clinical Chemistry:

FBS: Low dose female rat #I1070 had an FBS of 260 mg/dl; histopathologically this ra t was not remarkable.
BUN: All values, individual as well as mean, were normal.
SGOT: All values, individual as well as mean, were normal.
SGPT: The mean mid dose female and both high dose and female values were significantly higher than control. These differences are of no biological significance, however, since all mean as well as individual values except one were normal; high dose male rat #1117 had an SGPT wake of 105. Histopathologically this rat exhibited mild pulmonary Iyphocytosis.
GGTP: All values, individual as well as mean, were normal.
Total Protein: The mean value for the mid dose groups, male and female, as well as for the high dose groups, both male and female, was significantly higher than control. All mean as well as individual
values except one were normal; mid dose female rat #1082 had a Total Protein value of 8.52 g/dl. Histopathologically this rat exhibited pulmonary lymphocytosis.
Alk. Phos/ase: The low and high dose mean values were statistically less than the correspondirig control values. This is of no biological significance, however, since all values, mean as well as individual, were normal.


HISTOPATHOLOGY (PARENTAL ANIMALS): Histopathology examination of the reproductive organs from all Fo parents revealed no abnormalities.

OTHER FINDINGS (PARENTAL ANIMALS): None

Effect levels

Dose descriptor:
NOAEL
Effect level:
ca. 500 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: overall effects

Target system / organ toxicity

Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
2,4,7,9-Tetramethyl-5-decyne-4,7-diol, when fed to rats under the conditions of this experiment, showed no effect at 500 mg/kg/day but did have a toxic effect in the F1a generation at greater than or equal to 1,000 mg/kg/day while in the reproduction phase of this experiment there was a toxic effect at the 2,000 mg/kg/day level, a borderline effect at the 1,000 mg/kg/day level and no effect at 500 mg/kg/day.
Executive summary:

The purpose of this study was to evaluate the possible toxicity of 2,4,7,9-Tetramethyl-5-decyne-4,7-diol, when fed to the rat during a single generation reproduction study and for ninety one days to the F1a weanlings. The test material was mixed into the rats’ feed to provide dose levels of 0, 500, 1000, and 2000 mg/kg/day. Sexually mature Sprague-Dawley albino rats were divided into four groups, each consisting of ten male and twenty female rats. All Fo male rats, both test and control, were fed their respective diets until their litters reached the age of 21 days for weaning, when the Fo dams were sacrificed. The weanlings were randomized to their respective groups and carried on the same dose levels to the termination of the experiment. The only pertinent findings observed in the Fo parents were: 1. Slight decrease in the mean weaning weight of both male and female pups of the high-dose group, 2. Slight decrease in lactation indices of the high-dose group, 3. Decreased body weight and feed consumption of the high-dose female group, 4. Normal histology of the reproductive organs in the Fo parents. The following pertinent findings were observed in the F1a rats: 1. Slight decrease in the mean rate of body weight gain in the mid- and high-dose male and female rats; there was also significant decrease in this parameter in the low-dose male group during the first eight weeks, 2. Normal mean hematological findings, clinical chemistry findings, and urinalysis findings after 91 days on test, 3. Significant increase in the liver weight of the mid- and high-dose male and female test groups with corresponding increase in the liver-to-body weight ratios, 4. Corresponding histopathology of the liver of the mid- and high-dose male and female rats, showing mild to moderate centrilobular cloudy swelling of hepatocytes.

2,4,7,9-Tetramethyl-5-decyne-4,7-diol, when fed to rats under the conditions of this experiment, showed no effect at 500 mg/kg/day but did have a toxic effect in the F1a generation at greater than or equal to 1,000 mg/kg/day while in the reproduction phase of this experiment there was a toxic effect at the 2,000 mg/kg/day level, a borderline effect at the 1,000 mg/kg/day level and no effect at 500 mg/kg/day.