Registration Dossier

Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Remarks:
combined repeated dose and carcinogenicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1989
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented, according to accepted guidelines for a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)
Version / remarks:
-reliability scoring based on 2009 guideline
Deviations:
yes
Remarks:
-food efficiency not examined
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MALBIT®
- Physical state: Solid (crystal powder)
- Analytical purity: Not identified
- Lot/batch No.: 077094/1
- Expiration date of the lot/batch: July 10, 1990
- Stability under test conditions: Not reported
- Storage condition of test material: Stored at 10 to 20°C, relative humidity 50%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Italia S.p.A., Calco (Como), Italy
- Age at study initiation: Approximately 4 weeks old
- Weight at study initiation: About 75 to 85 g (males); about 60 to 70 g (females)
- Fasting period before study: Not reported
- Housing: Housed individually in stainless steel cages
- Diet (e.g. ad libitum): Standard diet coded as 4RF21 GLP powder, produced for the Charles River Company by its licensee Italiana Mangimi, of Settimo Milanese, ad libitum
- Water (e.g. ad libitum): Filtered water obtained from the municipal water main, ad libitum
- Acclimation period: about 2 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55±15
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 / 12


IN-LIFE DATES: From: Male: February 1, 1988; Female: February 4, 1988 To: Male: January 30 and 31 and February 1 and 2, 1989; Female: February 2, 3, 6, and 7, 1989

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
DIET PREPARATION: On the basis of the stability of the test article in the diet, appropriate amounts of calculated concentrations of the test article in the diet were prepared each week (on the same day) throughout the study period. The calculation of the test article concentrations was done on the basis of the last mean body weight and of the last mean food intake, separately for each sex/group.
For the first week, the concentration of the test article in the diet was calculated on the basis of 25 g of diet presumed to be consumed by the males and 20 g by the females, as well as of the body weight recorded the day before the start of treatment.
The total amount of test article calculated for each diet to be sufficient for a week was mixed into the basal diet by means of a mechanical powder mixing machine. Each freshly prepared diet was distributed weekly to all the rats of each group in amounts deemed sufficient for the animals’ needs. Each diet was prepared in an amount slightly greater than that calculated to be necessary for a week.

Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Stability, homogeneity, and concentration of the test article in the diet were analyzed by RBM (enzymatic method supplied by the Sponsor).
Stability of the test article in the diet at room temperature was checked at 2 concentration levels (2 and 30 mg/g) before the start of the treatment and at the concentration level of 135 mg/g before the 4th month of treatment. Homogeneity of the test article in the diet was checked at the above concentration levels and at the same times. Concentration of the test article in the diet was checked by RBM 4 times during 52 weeks of dosing on the first preparations of February 1 and 4, 1988, at 3 months (preparations of May 3 and 5, 1988), at 6 months (preparation of August 1 and 4, 1988), and on the preparations of February 16 and 20, 1989 (for organizational reasons, the determinations were shifted to 55 weeks of treatment of the carcinogenicity study). All the obtained values were within +9.512/-9.139% of the expected values.
Duration of treatment / exposure:
52 weeks
Frequency of treatment:
Continuous in the diet
Doses / concentrations
Remarks:
Doses / Concentrations:
0.5, 1.5, and 4.5 g/kg body weight/day
Basis:
nominal in diet
No. of animals per sex per dose:
20 per sex per dose
Control animals:
yes, plain diet
Details on study design:
- Dose selection rationale: Not reported
- Rationale for selecting satellite groups: Not reported
- Post-exposure recovery period in satellite groups: None
Positive control:
None

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice a day


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily



BODY WEIGHT: Yes
- Time schedule for examinations: Immediately prior to start of treatment period (Day 1), at weekly intervals for the first 12 weeks, and then every 4 weeks up to the end of 52-week dosing period.


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes (feeding study)
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No


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


WATER CONSUMPTION: No data


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Prior to the start of treatment (Week -1; Day -5/-4) and at Weeks 13 (Day 89/90), 26 (Day 180/182), and 52 (Day 359/360)
- Dose groups that were examined: 10 rats/sex/group (the first ones in numerical order of those surviving in each group)


HAEMATOLOGY: Yes
- Time schedule for collection of blood: At Weeks 14 (Days 92 to 95) and 26 (Days 176 to 179) of the dosing period and by the end of the treatment period (Week 51; Days 352 and 354)
- Anaesthetic used for blood collection: Yes (ether)
- Animals fasted: Yes
- How many animals: 10 animals/sex/group (the first ones in numerical order from those surviving in each group/sex)
- Parameters checked: Erythrocytes, haemoglobin, leukocytes, white blood cell differential count, mean corpuscular volume, haematocrit, mean corpuscular haemoglobin concentration (MCHC), mean corpuscular haemoglobin (MCH), platelets, and prothrombin time


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At Weeks 14 (Days 92 to 95) and 26 (Days 176 to 179) of the dosing period and by the end of the treatment period (Week 51; Days 352 and 354)
- Animals fasted: Yes
- How many animals: 10 animals/sex/group (the first ones in numerical order from those surviving in each group/sex)
- Parameters checked: Glucose, urea, creatinine, total bilirubin, alkaline phosphatase (SAP), serum glutamic oxaloacetic transaminase (SGOT or ASAT), serum glutamic pyruvic transaminase (SGPT or ALAT), total cholesterol, free cholesterol, esterified cholesterol, non-esterified fatty acids (NEFA), total protein, serum protein electrophoresis, albumin/globulin (A/G) ratio, sodium, potassium, calcium, inorganic phosphorus, and chloride. Gamma glutamyl transpeptidase (Gamma Gt), serum lipoprotein electrophoresis, and beta/alpha ratio were performed only at the end of the dosing period (Week 51).


URINALYSIS: Yes
- Time schedule for collection of urine: At Weeks 14 (Days 92 to 95) and 26 (Days 176 to 179) of the dosing period and by the end of the treatment period (Week 51; Days 352 and 354)
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters checked: Diuresis, specific gravity, semiquantitative examination, nitrites, protein, glucose, ketone bodies, urobilinogen, bilirubin, blood, pH, and microscopic examination


NEUROBEHAVIOURAL EXAMINATION: No

OTHER:
- Observation of palpable masses: Each rat was carefully palpated every 4 weeks in order to detect suspected masses.
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
- Organs checked: Femoral bone marrow smear, skin and mammary gland, urinary bladder, prostate, seminal vesicles, testes, epididymides, vagina, uterus, ovaries, spleen, stomach, intestine (duodenum, jejunum, ileum, cecum, colon, rectum), mesenteric lymph nodes, pancreas, liver, kidneys, adrenal glands, submandibular salivary glands and associated lymph nodes, sternum with bone marrow, heart, thymus, mediastinal lymph nodes, lungs, aorta, trachea, esophagus, thyroids with parathyroids, eyes, lacrimal glands (Harderian), exorbital lacrimal glands, tongue, nasal turbinates, brain, pituitary, skeletal muscle (biceps femoris), peripheral nerve (sciatic nerve), spinal cord (thoraco-lumbar tract), and gross lesions

HISTOPATHOLOGY: Yes. At the end of the 52-week treatment period, all organs were histologically seen in the animals of the control and high-dose groups; in the low and intermediate dosage group rats, liver, lungs, kidneys, and gross modifications were examined.
Other examinations:
None
Statistics:
The parameters statistically examined were body weight, food intake, hematology, blood chemistry, urinalysis (except for the semi-quantitative analysis and the microscopic examination of the sediment of the urine), organ weights (absolute and relative to body weight), and cecum and colon diameters. All data were compared according to the decision tree. If one transformation was successfully applied, ANOVA and Dunnett’s test (when necessary) were applied on transformed data.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
no effects observed
Haematological findings:
no effects observed
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
Mortality: No compound-related deaths occurred during the chronic study with the test article mixed into the diet. No animals of Groups 3 (1.5 g/kg body weight/day) and 4 (4.5 g/kg body weight/day) died. A total of seven rats [one male and two females of the control group and two males and two females of Group 2 (0.5 g/kg body weight/day)] died during the 52 weeks of the chronic study. They are listed in Table 1 below together with clinical observations and the cause of death.

In addition, these rats presented some other incidental changes the most relevant of which were as follows:
-Rat no. 3873 presented severe reactive hyperplasia and extramedullary erythropoiesis of the spleen, moderate necrosis of single hepatocytes and widespread neutrophil infiltration in blood vessels, there being consequent to the ulcerated mass;
-Rat no. 3863 presented apical necrosis of the tongue due to the blood sampling from sublingual veins performed two days before death;
-Rat no. 3945 showed mineralization of the aorta and stomach, degeneration and fibrosis of the heart and sclerosis of mesenteric blood vessels consequent to chronic renal glomerulonephropathy;
- Rat no. 4005 showed moderate degeneration of the head muscle and subacute inflammation related to the manner of death.
Moreover, in most of the animals listed above, moderate or severe atrophy of the thymus and/or pancreas were observed and were considered related to agonal conditions.

Clinical Signs: During the 52 weeks of the chronic toxicity study, no treatment-related clinical signs were noted. In particular, no diarrhea or soft stools were observed for the animals of either sex given test article at the various dose levels.
A number of spontaneous clinical changes were noted in both treated and control animal groups with comparable frequency. These changes are summarized in the table of clinical signs (Table 2) that appears below, where the total number of animals affected is also given. Moreover, a subcutaneous mass was clinically noted in three males (no. 3793 of control group; no. 4071 of Group 3; no. 4219 of Group 4) and two females (no. 4014 of Group 2; no. 4286 of Group 4).

The most common clinical findings were abnormal growth of the incisor teeth and chromodacryorrhea. These findings, together with the other clinical changes sporadically seen in the various experimental groups were considered incidental, as they can be observed also in untreated rats kept for a prolonged period of time in the same housing conditions and fed a powdered diet.

BODY WEIGHT AND WEIGHT GAIN
Using statistical analysis, no significant differences between control and treated animals of either sex were recorded at any time.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
No major differences in food consumption were observed between control and treated animals of either sex during the 52 weeks of the chronic study. Occasional slight but statistically significant differences from controls were found for the treated groups of males. Increases were recorded at Week 2 for Groups 2 and 3; at Week 20 for Group 3, and at Week 48 for Group 4. Only in the case of females treated with the highest dose were decreases found at Week 12 and at Week 52 of the dosing period. All the above changes were considered incidental, however, mean food consumption of females of Group 4 was in general negligibly lower than that of the controls throughout the study period.

OPHTHALMOSCOPIC EXAMINATION
No treatment-related eye abnormalities were found. Unilateral, incidental eye changes were observed in a few animals of all groups, including the control group, as reported below:
-focal hemorrhage of the vitreous body, observed in one male of Group 2 (no. 3934) at Week 13 and at Week 26;
-Diffuse hemorrhage (anterior and posterior segments), observed in one control female (no. 3864) at the Week 26 examination time, followed by a diffuse cataract at Week 52;
-Focal, slight corneal opacity, observed in one female of Group 4 (no. 4287) at Week 13 and at Week 52, in one male and one female of Group 3 (nos. 4072 and 4143, respectively) and in one female of Group 4 (no. 4287).

HAEMATOLOGY
The significant differences that emerged from statistical analysis of the data obtained at the various examinations carried out throughout the dosing period are given in Table 3. No changes attributable to the test compound oral administration were found in the treated animals of either sex at any time. A number of statistically significant differences between control and treated animals were recorded at the various examination times.
Among these, the increase in erythrocyte number and hemoglobin concentration observed at Week 14 for the males of Groups 3 and 4 and at Week 26, only for the males of Group 3 (which also showed a statistically significant increase in the hematocrit value at Week 14) was considered incidental because it was not time or dose-related, and the individual values were within the norm; in any case, the above changes were not considered to have toxicological relevance.
The decrease, compared to control values in the leukocyte number, which was observed for Group 3 females at all examination times and for females of Group 2 at Weeks 14 and 26, was also considered incidental. This evaluation is based on the fact that the above variation was confined to the low and intermediate dose levels and that all the individual values were within a normal range of variability.
As given in Table 3, variations of the erythrocyte indices (MCHC and MCH) were found at the pre-terminal test (Week 51). Even though accepted as statistically significant, they were considered incidental because of their negligible intensity, all the individual values falling within the norm. Examination of the individual data revealed an erythrocyte number, and hemoglobin and hematocrit values below the range accepted by us as normal for male no. 4214 of Group 4 at the pre-terminal examination, a high total leukocyte number was also found for this animal.

CLINICAL CHEMISTRY
At the examinations performed throughout the dosing period (Weeks 14, 26, and 51) a number of significant differences between control and test article-treated animals emerged from statistical evaluation of the blood chemistry data. They are given in Table 4.
A few differences from controls were recorded in the treated animals of both sexes at the various examinations carried out during the 52 weeks of dosing. Even though they were accepted as statistically significant, they were considered incidental as they were transient and/or confined to the low and intermediate dose levels and all the individuals values fell within the norm.
Examination of individual data revealed some incidental increases in the SGOT and SGPT activities at the various tests, mainly in females of the lowest dose.
At the pre-terminal test (Week 51), abnormal total bilirubin, total, free and esterified cholesterol values were found for male no. 3932 of Group 2 and for male no. 4077 of Group 3, for which an abnormal percentage of alpha globulin fraction was also observed.

-Males:
Animals treated with test article at the various dose levels showed a slight, not dose-related increase in mean creatinine values at the pre-terminal examination. For this change, which reached statistical significance, some individual values above the range of the control values were observed in each of the treated groups, but no values above the normal range of variability were found.
Other modifications of some blood chemistry parameters were seen only for males treated with the highest dose group (Group 4), which showed mean total cholesterol values slightly lower than those of the controls at both the mid-term and pre-terminal examinations. Statistical significance was reached at Week 26.
At the above examination times, both cholesterol fractions (free and esterified) appeared slightly reduced, when compared to control values, reaching statistical significance in most cases.
The above modifications were accompanied by a decrease in mean NEFA values at both Week 26 and Week 51 tests, with some individual data below the range of the controls.
The lipoprotein electrophoresis performed at the pre-terminal examination did not reveal notable changes in the treated groups, when compared to the control group.
-Females:
No major changes from controls were observed in the test article-treated females at any time. The only minor variations were the slight, not dose-related reduction in mean inorganic phosphorus, which was transiently observed at the Week 26 examination time in all the treated groups. The variation, which proved significant at the statistical evaluation, was not characterized by individual values below the norm.
Only females treated with the highest dose showed slight modifications of the serum lipoprotein pattern at the pre-terminal examination. This consisted of an increase, when compared to control values, in the alpha fraction percentage (significant at the statistical evaluation) and an consequent slight decrease in the Beta/Alpha ratio.
No other blood chemistry parameters were considered to have influenced by treatment in animals of either sex.

URINALYSIS
No treatment-related modifications were found for the animals of either sex at any time.
For the urine parameters statistically evaluated (diuresis, specific gravity, and pH), the only significant difference from controls was an incidental increase in diuresis value for the males treated with the lowest dose (Group 2), this variation being confined to the Week 14 examination time.
Assessment of the semi-quantitative analysis of the urine and sediment microscopy did not reveal changes attributable to test article oral administration at the dose levels tested in this study.

ORGAN WEIGHTS
No compound-related changes were found at the examination of the mean absolute and relative values obtained in all groups. However, statistical analysis showed a few significant differences among treated and control groups. In males, they were a slight increase in absolute weight of adrenals of Groups 2 and 3, with a significant increase of the relative value at the intermediate dosage (Group 3), and a slight increase of the absolute and relative weight of the pituitary in Group 2.
These increases were considered incidental as they were not dose-related and were correlated with individual rats having in these organs spontaneous incidental pathology not infrequent in untreated rats of this strain and age used in our laboratory in other trials. In particular, male no. 3933 of Group 2 had increased weight of adrenals related to the histologically seen pheochromocytoma, and male no. 3944 of the same group had increased weight of pituitary related to a pars anterior adenoma.

GROSS PATHOLOGY
No compound-related changes were found in the treated animals. All findings described in autopsy were considered spontaneous incidental pathology, except the hepatic reddish area, seen in Group 1 male no. 3796 that was considered incidentally caused by the barbiturate intraperitoneal injection performed to anesthetize the rats before killing. Most of them were found with comparable frequency and severity also in control rats of this experiment. A few modifications were found only in treated or control rats, but in the case of the treated rats, they failed to show any compound-correlation. Moreover, they clearly appear correlated with incidental spontaneous pathology not infrequently encountered in rats of the same strain and age used in the laboratory in other experiments.
Among the most frequent were liver pale appearance, dark area and/or increase in size of adrenals, more frequent in females and mostly due to cystic dilatation of sinusoids as seen at histology, mammary galactocele, pituitary congestion and/or increase in size (mostly due to anterior gland hyperplasia or adenoma) and slight gastric ulcers of the glandular mucosa.
The outer surfaces of the gut in its different parts (ileum, cecum, and colon) showed no differences in aspect between controls and treated rats. The cecum after measurement was opened and the inner surface also showed no differences. Moreover and in particular, no soft stools were found in the cecum or colon of the treated or control rats; congested cecum was found in two males (nos. 4082 and 4084) treated with the intermediate dosage – 1.5 g/kg body weight/day – but this alteration was also found in a control male (no. 3796). A single case of slight cecum meteorism was seen in male no. 4217 of the highest dose.
Among the other observations, a few masses or nodules were macroscopically described and were also considered of incidental nature, because a dosage-relationship was lacking. Of these, the pituitary mass seen in Group 2 female no. 4014 was histologically diagnosed as a adenoma of the anterior pars; subcutaneous masses seen in females no. 4014 of Group 2 and no. 4286 and no. 4296 of Group 4 were diagnosed as fibroadenomas; the cutaneous nodule in male no. 3793 of Group 1 was a papilloma and in male no. 4219 of Group 4 was an area of severe hyperkeratosis and acanthosis.

HISTOPATHOLOGY: NON-NEOPLASTIC
At the end of the 52-week treatment period, all organs were histologically seen in the animals of the control and high-dose groups; in the low and intermediate dosage group rats, liver, lungs, kidneys, and gross modifications were examined.
No compound-related modifications were seen.
Most modifications were considered age-related spontaneous incidental pathology commonly found in untreated rats of the same age and strain as those used in this experiment and were comparably distributed among controls and treated rats.
The following were the more frequent liver inflammatory changes or vacuolation consistent with fatty changes; spleen erythropoiesis and, in females pigment increase; lymph node sinus erythrophagocytosis, heart fiber degeneration, as usually seen, more frequent in males; thymus atrophy, pancreas pigment-laden macrophages more frequent in males; cortical adrenal gland areas of altered cells, degeneration and sinusoidal dilatation more frequent, as known, in females; prostate atrophy and presence in the glands of corpora amylacea, early signs of ovarian atrophy; uterine gland squamous metaplasia and mammary gland galactocele.
Moreover, in the gastrointestinal tract a few slight gastric ulcers were seen. Slight dilatation of ileum, jejunum, and colon, and slight congestion of the cecum were noted with comparable frequency in control and treated rats.
The examination of kidney showed chronic progressive glomerulonephropathy in few treated and control males and a control female. This spontaneous pathology common in Sprague Dawley rats of this age, appeared from slight to severe in degree. Moreover, some other control and treated rats – particularly males – had the first slight signs of the above-mentioned renal pathology, as basophilia, degeneration and sclerosis of tubules, casts and interstitial round cell inflammation.
Both the initial signs and the chronic progressive glomerulonephropathy were clearly comparable in frequency and degree among treated and control rats.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
Among the age-related incidental modifications, some neoplastic or hyperplastic changes were seen pituitary pars anterior hyperplasia in Group 1 males nos. 3790, 3791, 3797 and females nos. 3868, 3871, 3874, and 3876 and in Group 4 male no 4217 and females nos. 4291 and 4295; pituitary pars anterior adenoma in Group 1 female nos. 3861 and 3870, in Group 2 male no. 3944 and females nos. 4012, 4014, and 4015 and in Group 3 female no. 4159, adrenal gland malignant pheochromocytoma in Group 2 male no. 3933; ovary granulosa-theca cell tumor in Group 3 female no. 4016; uterine endometrial malignant fibrosarcoma in Group 1 female no. 3866 and in Group 3 female no. 4142; uterine endometrial stromal polyp in Group 3 female no. 4145, mammary gland fibroadenoma in Group 2 female no. 4014 and in Group 4 females nos. 4286 and 4296; skin papilloma in Group 1 male no. 3793; thyroid follicle adenoma in Group 1 male no. 3793 and in Group 4 male no. 4218.
The neoplastic changes were also considered unrelated to treatment because most of them were also present in control rats, or they can be found with a certain degree in untreated rats of the same age or strain, or a dosage-relationship was lacking.
The liver focus of sinusoid congestion and degeneration of hepatocytes seen in Group 1 male no. 3796 was considered incidental due to needle trauma, caused during barbiturate intraperitoneal injection to anesthetize animals for killing.
Subacute inflammation with cartilage degeneration and mineralization of the ear pinna seen in Group 4 male no. 4219 and female nos. 4289 and 4297 were probably caused by the long lasting presence of the ear tag used to identify the animals.

OTHER FINDINGS
Cecum and Colon Diameter measurement:
The widest diameters respectively of the cecum and colon were measured at autopsy as requested by the Sponsor. No differences emerged among treated and control groups for colon values. The mean cecum diameter slightly increased in males of Groups 2 and 4, reaching statistical significance in Group 4. This is due in this group to the higher values of only 3 rats (nos. 4213, 4219, and 4220) probably because spontaneous pathology occurred in many organs of them. Mean values in Groups 1, 2, 3, and 4 males were respectively 15.74, 18.28, 16.65, and 18.95. This variation was also considered incidental because the increase was negligible, not dose-correlated, and because a trend towards a decrease was found in females (of Groups 2 and 4) when compared to control females.

Effect levels

Dose descriptor:
NOAEL
Basis for effect level:
other: Author did not identify a NOAEL.
Remarks on result:
not determinable
Remarks:
no NOAEL identified

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

 

Table 1: Mortality and Clinical Signs

Animal number; Sex

Group; Dose level

Week; Day of death

Clinical signs

Cause of death

3794; Male

1; 0 g/kg body weight/day

26; 178

No clinical signs

Ether anesthesia for blood sampling

3863; Female

1; 0 g/kg body weight/day

51; 354

Chromodacryorrhea, piloerection, thinning, weakness and sedation starting from Week 48; subcutaneous nodule on the left dorsal region starting from Week 49

Anterior pituitary adenoma

3873; Female

1; 0 g/kg body weight/day

46; 321

Subcutaneous mass on the thorax first observed at Week 36

Mammary ulcerated adenocarcinoma with lung metastasis

3939; Male

2; 0.5 g/kg body weight/day

14; 95

No clinical signs

Ether anesthesia for blood sampling

3945; Male

2; 0.5 g/kg body weight/day

49; 339

Thinning, piloerection, nasal discharge, decrease of respiratory rate, pallor of the apparent mucosae, weakness and sedation during the last week of preceding death

Several renal glomerulonephropathy

4005; Female

2; 0.5 g/kg body weight/day

13; 89

Found trapped with teeth in feeder at Week 11, with consequent deflection of the nose profile. Chromodacryorrhea, respiratory distress, piloerection, thinning and sedation during the last few days preceding death.

Caught in feeder by teeth

4009; Female

2; 0.5 g/kg body weight/day

11; 75

Found dead trapped with teeth in feeder

Caught in feeder by teeth

 

 

Table 2: Clinical signs (number of rats affected)

 

Group 1; 0 g/kg body weight/day

Group 2; 0.5 g/kg body weight/day

Group 3; 1.5 g/kg body weight/day

Group 4; 4.5 g/kg body weight/day

Male

Female

Male

Female

Male

Female

Male

Female

Abnormal growth of incisors

4

3

5

2

7

1

1

-

Chromodacryorrhea

3

2

3

1

5

1

-

-

Piloerection

-

1

1

-

2

-

-

-

Thinning

-

1

1

-

2

-

-

1

Nasal discharge

-

-

-

-

1

-

-

-

Respiratory distress

-

-

-

-

1

-

-

-

Auricular swelling

-

-

-

-

1

-

-

-

Intraocular darkness

-

1

-

-

1

-

-

-

Intraocular opacity

-

1

-

-

-

-

-

-

Alopecia

-

1

2

-

1

-

-

-

Skin ulcer

1

-

-

-

-

-

-

-

Crust formation on tail

-

-

-

-

-

-

1

-

Tail apex necrosis

-

-

1

-

-

-

-

-

Blood-smeared fur

-

-

-

1

-

-

-

-

 

 

Table 3: Hematology Data

Hematological parameters

Week 14

Week 26

Week 51

Males

Females

Males

Females

Males

Females

Erythrocytes

3+/4+

/

3+

/

/

/

Hemoglobin

3+/4+

/

3+

/

/

/

Hematocrit

3+

/

/

/

/

/

Leukocytes

/

2-/3-

/

2-/3-

/

3-

MCHC

/

/

/

/

3+

2+/3+

MCH

/

/

/

/

/

4+

Prothrombin time

2+

/

/

/

/

/

Legend:

2, 3, and 4 = experimental group numbers

+ = significant increase, when compared to control group

- = significant decrease, when compared to control group

/ = no significant difference, when compared to control group

 

Table 4: Blood Chemistry Data

Blood chemistry parameters

Week 14

Week 26

Week 51

Males

Females

Males

Females

Males

Females

Urea

/

/

/

/

2+

/

Creatinine

/

/

/

/

2+/3+/4+

/

Alkaline phosphatase

/

/

/

2-/4-

/

/

SGOT

/

/

4-

/

/

/

Albumin

/

/

/

/

/

3-

Globulin

/

/

/

/

/

3+

A/G ratio

/

/

/

/

/

/

Alpha 1 globulin

/

/

/

/

/

3+

Alpha 2 globulin

/

/

/

/

/

3+

Total cholesterol

/

/

4-

/

/

/

Free cholesterol

/

/

4-

/

4-

/

Esterified cholesterol

/

/

4-

/

/

/

NEFA

/

/

4-

/

4-

/

Alpha lipoprotein

/

/

/

/

/

4+

Sodium

3+/4+

/

/

/

/

/

Potassium

3+

/

4-

/

/

/

Calcium

/

/

/

4+

/

/

Chloride

3+

/

/

/

/

/

Inorganic phosphorus

/

/

/

2-/3-/4-

/

/

Legend:

2, 3, and 4 = experimental group numbers

+ = significant increase, when compared to control group

- = significant decrease, when compared to control group

/ = no significant difference, when compared to control group

Applicant's summary and conclusion

Executive summary:

NOAEL values were not reported by the study authors. Review of the study data suggests that a NOAEL of 4.5 g/kg body weight/day (highest level administered) can be considered for male and female rats based on a lack of toxicity.