2-ethylaminoethanol

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

2008-11-25 to 2009-01-2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guidelilne study; GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3650 Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-methylaminoethanol

EC Number:

203-710-0

EC Name:

2-methylaminoethanol

Cas Number:

109-83-1

IUPAC Name:

2-(methylamino)ethanol

Details on test material:

- Name of test material (as cited in study report): Methylaminoethanol (Test item No.07/0540-2)
- Substance type: organic
- Physical state: colorless liquid
- Analytical purity: 99.7 area-% (Analytical Report: 07L00323)

- Purity test date: November 06-07, 2007
- Lot/batch No.: from continuous production, production date 24 Oct 2007
- Expiration date of the lot/batch: 24 Oct 2009

- Stability under test conditions: The stability of the test item under storage conditions over the test period was guaranteed by the sponsor, and the sponsor holds this responsibility
- Storage condition of test material: Room temperature, under N2

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH
- Age at study initiation: 10-11 weeks
- Weight at study initiation: The weight variation of the animals used did not exceed 20 percent of the mean weight of each sex.
- Fasting period before study: Animals were fasted prior to blood collection for clinical chemistry and haematology
- Housing: individually in type M III polycarbonate cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: yes, 10 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C):20-24 °C,
- Humidity (%):30-70%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test substance was applied as a solution. To prepare the solution, the appropriate
amount of test substance was weighed out depending on the desired concentration. Then the vehicle (highly deionized water) was filled up to the desired volume, subsequently mixed using a magnetic stirrer. The test-substance solutions were prepared in such intervals that the stability was guaranteed.

VEHICLE
- highly deionized water
- Concentration in vehicle:0.5, 1.5 and 4.5 g/100 mL
- Amount of vehicle (if gavage): 100 mL
- Lot/batch no. (if required):
- Purity:

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The analyses of the test-substance preparations were carried out at the Analytical Chemistry Laboratory of the Experimental Toxicology and Ecology of BASF SE. The stability of the test substance in highly deionized water at room temperature for a period of 10 days was proven before the start of the administration period (Project No.: 01Y0540/078008). The concentration control analyses revealed that the values were in the expected range of the target concentration, i.e. were in a range of about 90.1-102.2% of the nominal concentration.

Duration of treatment / exposure:

The duration of treatment covered a 2-week pre-mating and mating period in both sexes, approximately 1 week post-mating in
males, and the entire gestation period as well as 4 days of lactation in females (35 days for males and 55 days for females).

Frequency of treatment:

daily at the same time in the morning

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 50, 150 and 450 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
- Rationale for animal assignment (if not random): randomized
- Rationale for selecting satellite groups: no sattelite groups
- Post-exposure recovery period in satellite groups: not applicable
- Section schedule rationale (if not random): randomized

After the acclimatization period, at least 13 days after the beginning of treatment, males and females from the same test group were mated overnight in a ratio of 1:1.
On study day 32, a functional observational battery and motor activity measurement were carried out in the first five male animals per group.
The females were allowed to litter and rear their pups until day 4 after parturition. On PND 4, all pups were sacrificed and examined.
On study day 53, a functional observational battery and motor activity measurement was carried out in the first five female animals (with litter, groups 0 and 1; with positive sperm in vaginal smear, groups 2 and 3) per group.
From the first 5 male animals and the first 5 selected female animals urinalysis were carried out on study days 34 (males) and 50 (females). Clinicochemical and hematological examinations were carried out on study days 35 (males) and 55 (females).
At the end of the study (males: study day 35, females: study day 55), the animals were sacrificed after a fasting period (withdrawal of food) for at least 16-20 hours.

Positive control:

no

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

A check for moribund and dead animals was made twice daily on working days and once daily on Saturdays, Sundays and public holidays. If animals were in a moribund state, they were sacrificed and necropsied.
- Time schedule: A cageside examination was conducted before and after treatment for any signs of morbidity, pertinent behavioral changes and signs of overt toxicity. Abnormalities and changes were documented for each animal.
- Cage side observations checked in table [No.1] were included.

DETAILED CLINICAL OBSERVATIONS: Yes.
- Time schedule: Detailed clinical observations were performed in all animals prior to the administration period and thereafter at weekly intervals. The findings were ranked according to the degree of severity, if applicable. The animals were transferred to a standard arena (50 x 37.5 cm with side borders of 25 cm high).
- The parameters examined are listed in the Table 1.

BODY WEIGHT: Yes
- Time schedule for examinations: once a week at the same time of the day (in the morning).

FOOD CONSUMPTION AND COMPOUND INTAKE :
Generally, food consumption was determined once a week (in a period of 7 days) for male and female parental animals, with the following exceptions:
• Food consumption was not determined during the mating period (male and female F0 animals).
• Food consumption of the F0 females with evidence of sperm was determined on GD 0, 7, 14 and 20.
• Food consumption of F0 females, which gave birth to a litter, was determined on PND 0 and 4. Food consumption was not determined in females without positive evidence of sperm (during the mating period of dams used in parallel) and females without litter (during the lactation period of dams used in parallel).

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 data

OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations:
- Dose groups that were examined:

HAEMATOLOGY: Yes
- Time schedule for collection of blood:In the morning
- Anaesthetic used for blood collection: Yes (isoflurane (Isoba®, Essex GmbH Munich, Germany)).
- Animals fasted: No data
- How many animals: 5 per sex and group
- Parameters checked in table [No.4] were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: In the morning, day 35 (males), day 55 (females)
- Animals fasted: Yes
- How many animals: 5 per sex and group
- Parameters checked in table [No. 4] were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: overnight, day 35 (males), day 55 (females)
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters checked in table [No. 5] were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes. Functional Observation Battery
- Time schedule for examinations: A functional observational battery was performed at the end of the administration period (day 32 (males), day 53 (females) starting at about 10:00 h.
- Dose groups that were examined: in the selected five animals per sex and group.
- Battery of functions tested:
- Home cage observations: The animals were observed in their closed home cages; any disturbing activities (touching
the cage or rack, noise) were avoided during these examinations in order not to influence the
behavior of the animals. Attention was paid to:
1. posture
2. tremors
3. convulsions
4. abnormal movements
5. impairment of gait
6. other findings
- Open field observations: animals moved to standard arena, the parameters examined are listed in the Table 2.
- Sensory activity / grip strength: The animals were removed from the open field, parameters tested are listed in the Table 3
-Motor activity:
The motor activity (MA) was measured on the same day as FOB was performed in the selected 5 parental
males and females per group. The examinations were performed using the Multi-
Varimex system supplied by Columbus Instruments Int. Corp., Ohio, U.S.A. For this purpose,
the animals were placed in cages for the time of measurement. Four beams were allocated
per cage. The number of beam interrupts was counted over 12 intervals for 5 minutes in each
case. The sequence at which the animals were placed in the cages was selected at random.
The measurement was started at about 14:00 h. On account of the measuring variant
"staggered", the starting time was varied by the time needed to place the animals in the
cages. For each animal, measurement was started individually when the 1st beam was
interrupted and ended exactly 1 hour later. The animals received no food or water during the
measurements. After the transfer of the last animal in each case, the room where the
measurements were carried out was darkened.

OTHER: reproduction indices, clinical observation of litters/pups and their necropsy findings are recorded in section 7.8.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes. All parental animals were sacrificed by decapitation using isoflurane anesthesia. The exsanguinated animals were necropsied and assessed by gross pathology; special attention was given to the reproductive organs. The animals, which died intercurrently or were sacrificed in a moribund state, were necropsied as soon as possible after their death and assessed by gross pathology. Organ weights were recorded (see Table6).
HISTOPATHOLOGY: Yes (see table 7)

Other examinations:

Reproductive organs of perental animals and litters/pups (sections 7.8.1 and 7.8.2)

Statistics:

Food consumption, body weight and body weight change (parental animals): DUNNETT-test (two-sided)
Urinalysis, except color, turbidity, volume and specific gravity : FISHER'S EXACT test
Feces, rearing, grip strength of forelimbs and hindlimbs, landing foot-splay test, motor activity, clinical pathology parameters, urine volume,urine specific gravity and organ weights : KRUSKAL-WALLIS test (two-sided).

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

: at 450 mg/kg bw/d, mortality, apathy, convulsions, salivation

Mortality:

mortality observed, treatment-related

Description (incidence):

: at 450 mg/kg bw/d, mortality, apathy, convulsions, salivation

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

: reduced in both sexes at 450 mg/kg bw/d and in males at 150 mg/kg bw/d

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

: reduced at 450 mg/kg bw/d

Food efficiency:

not specified

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

: no consistent changes

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

: no consistent changes

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

: at 150 and 450 mg/kg bw/s

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY

In test group 3 (450 mg/kg bw/d) one male animal (animal no. 37) was found dead within the first week of the study. One male animal (animal no. 32) of test group 3 (450 mg/kg bw/d) was sacrificed in a moribund state in study week 2. In addition, one female animal (animal no. 126) of test group 2 (150 mg/kg bw/d) was sacrificed on GD 23 because of an inability to deliver.

In test group 3 (450 mg/kg bw/d), salivation after treatment was observed in study week 1 in one male animal (animal no. 36) and in study weeks 1, 6 and 7 in six female animals. Poor general state was observed in test group 3 (450 mg/kg bw/d) in study weeks 1 and 2 in two male animals (animal nos. 32 and 36) and in study weeks 1, 6 and 7 in two female animals (animal nos. 132 and 135). In test group 3 (450 mg/kg bw/d), apathy was observed in study week 2 in one male animal (animal no. 32). Clonic convulsion was observed in test group 3 (450 mg/kg bw/d) in study week 1 in one male animal (animal no. 39).

The detailed clinical observations on study days 0, 7, 13, 21, 28 in males and females and
additionally day 35, 42 and 49 in female animals did not reveal any additional abnormalities
in animals of test groups 0-3 (0, 50, 150 and 450 mg/kg bw/d).

BODY WEIGHT AND WEIGHT GAIN
In test group 3 (450 mg/kg bw/d) male animals’ body weight was significantly lower in week 4
and body weight change was already significantly lower between weeks 1-2 and in summary
between weeks 0-4. In test group 2 (150 mg/kg bw/d) male animals’ body weight change was
significantly lower between weeks 3-4.

Body weights and body weight changes of all female animals treated with 50, 150 or 450
mg/kg bw/d were not significantly changed during premating.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
Significantly decreased food consumption of the male animals of test group 3 (450 mg/kg
bw/d) was observed during the first two study weeks.
Food consumption of the female rats of test group 3 (450 mg/kg bw/d) was significantly
decreased during the first study week.

HAEMATOLOGY
At the end of the administration period red blood cell counts (RBC), hemoglobin
concentrations and hematocrit values were decreased in rats of both sexes in test groups 2
(150 mg/kg bw/d) and 3 (450 mg/kg bw/d).
Additionally, the hematocrit values were significantly decreased in females and males of test
group 1 (50 mg/kg bw/d). This decrease compared to the controls was below 10% (males:
5%; females 7%), and it was the only dose-dependently changed red blood cell parameter in
this test group. Therefore, the hematocrit decrease in rats of test group 1 (50 mg/kg bw/d)
was regarded as treatment-related but not adverse (reference 1 and 2).
The mean corpuscular volume (MCV) was decreased in male rats of all treatment groups (not
significantly changed in test group 3 [450 mg/kg bw/d]). The measured MCV and RBC values
were used to calculate the hematocrit values. In male rats of test group 1 (50 mg/kg bw/d) the
MCV reflected the decreased hematocrit value because the RBC was not changed.
Therefore, the decreased MCV in these rats was regarded as treatment-related, but not
adverse as mentioned above.
In female rats of test group 3 (450 mg/kg bw/d) the relative reticulocyte counts were
increased.
No significant change was observed in the total white blood cell counts (WBC) of treated rats.
However, some changes in the relative and absolute differential blood cell counts were
measured (males: increased relative neutrophil counts and decreased relative eosinophil
counts in test group 3 [450 mg/kg bw/d], decreased relative monocyte counts in test group 2
[150 mg/kg bw/d]; females: decreased absolute eosinophil counts in test group 3 [450 mg/kg
bw/d], decreased relative neutrophil counts and increased relative lymphocyte counts in test
group 2 [150 mg/kg bw/d]).
These changes were regarded as being incidental and not treatment-related because they
were not dose-dependently changed and not consistent in both sexes.
The prothrombin time was shortened in rats of both sexes of test group 3 (450 mg/kg bw/d)
and, additionally, in females of test group 2 (150 mg/kg bw/d).

CLINICAL CHEMISTRY
Liver enzyme activity was not changed in male and female rats of any test substance-treated
group.
The urea levels were increased in males of test group 2 (150 mg/kg bw/d) and in rats of both
sexes in test group 3 (450 mg/kg bw/d).
The total bilirubin concentrations were significantly higher in rats of both sexes in test groups
2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d).
The total protein and the albumin levels were increased in females of test group 1 (50 mg/kg
bw/d) and higher (total protein level was not significantly increased in test group 3 [450 mg/kg
bw/d]), although the increases were not dose-dependent.
In males the total protein levels were significantly increased in test groups 1 (50 mg/kg bw/d)
and 2 (150 mg/kg bw/d) and the albumin concentrations in test group 2 (150 mg/kg bw/d),
only. These parameters were not changed dose-dependently, and the deviated values were
within the historical control ranges (total protein: 62.45-69.74 g/L; albumin 36.12-39.76 g/L).
Therefore, these deviations were regarded as non-adverse effects.
The sodium concentrations were increased in rats of both sexes in test groups 2 (150 mg/kg
bw/d) and 3 (450 mg/kg bw/d) and, additionally, in males of test group 1 (50 mg/kg bw/d).
The sodium mean in males at least of the low dose group was within the historical control
range (140.9-147.1 mmol/L). Apart from this, only this electrolyte level was deviated in test
group 1 (50 mg/kg bw/d). Therefore, the sodium levels increase at least in males of the low
dose group was regarded as a non-adverse effect.
In males of test groups 1 (50 mg/kg bw/d) and 2 (150 mg/kg bw/d) the cholesterol levels were
decreased. The parameter was not changed dose-dependently, and such deviation was not
observed in females. Therefore, the cholesterol levels decrease in males of test groups 1 (50
mg/kg bw/d) and 2 (150 mg/kg bw/d) was regarded as non-adverse.
In treated females the potassium concentrations were significantly higher in test group 1 (50
mg/kg bw/d), the creatinine levels were higher in test group 2 (150 mg/kg bw/d) and the
magnesium concentrations were increased in test groups 1 and 2. These values were not
changed dose-dependently, and the deviations of these parameters were not measured in
male rats. Therefore, these changes were regarded as incidental rather than treatmentrelated.

URINALYSIS
In rats of both sexes in test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) the incidence
of blood (haemoglobin) was found higher compared to the controls (in females of test group 3
not significant). Additionally, the incidence of higher leucocyte counts in the urine sediment
was significantly increased in males of test group 2 (150 mg/kg bw/d). However, no
significantly higher leucocyte counts were found in the urine sediment of rats of both sexes of
test group 3 (450 mg/kg bw/d).
In males of test group 3 (450 mg/kg bw/d), the incidence of higher transitional cell counts was
increased.

The urine was discolored in almost all the males and females of test group 3 (450 mg/kg bw/d) from study week 1 onwards.

NEUROBEHAVIOUR

Home cage observations: No test substance-related or spontaneous findings in male and female animals of all test
groups during the home cage observation were observed.

Open field observations: The open field observations did not reveal any test substance-related findings in male and
female animals of all test groups.

Sensorimotor tests/reflexes: There were no test substance-related findings in male and female animals of all test groups.
Any deviations from "zero values" were equally distributed between test substance-treated
groups and controls or occurred in single animals only. Therefore, these observations were
considered as being incidental.

Motor activity measurement: There were no significant deviations concerning the overall motor activity (summation of all
intervals) in the male and female animals of all test groups in comparison to the concurrent
control group.
Regarding single intervals, in males of test group 1 and 2 (50 and 150 mg/kg bw/d) two
isolated significantly increased values were measured at interval 4. These findings were
considered as being incidental since the overall motor activity was not changed and no
findings were observed for female animals.

ORGAN WEIGHTS

Absolute organ weights: When compared to control group 0 (set to 100%), the mean absolute weights of the organs listed in the Table 8 were significantly increased or decreased. All other mean absolute weight parameters did not show significant differences when
compared to test group 0 (control).
Relative organ weights: The terminal body weight was significantly decreased in males of test group 3 (450 mg/kg
bw/d) and in females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) resulting in
significant, secondary weight changes in various organs (Table 9)

GROSS PATHOLOGY
Parental animals
Three males of test group 3 (450 mg/kg bw/d) showed erosions or ulcers in the glandular
stomach.
The liver was enlarged in three males and one female of test group 2 (150 mg/kg bw/d) as
well as in three males and five females of test group 3 (450 mg/kg bw/d). Four males of test
group 1 (50 mg/kg bw/d) and four males of test group 2 (150 mg/kg bw/d) showed a
prominent acinar pattern of the liver.
The mesenteric lymph nodes were red discolored in one female of test group 2 (150 mg/kg
bw/d) and in two females of test group 3 (450 mg/kg bw/d).
All other gross lesions occurred either singly or were biologically equally distributed over the
control group and the treatment groups, and they were considered to be incidental.

HISTOPATHOLOGY: NON-NEOPLASTIC (see Table 10)
Kidneys: In kidneys, a multifocal degeneration was observed in proximal tubular cells at the transition of cortex to medulla in males of all treatment groups as well as in females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). The severity increased dose-dependently. The tubular degeneration resulted in increased kidney weights in males and females of the test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). The occurrence of tubular degeneration in kidneys was related to treatment and assessed as an adverse effect. In addition, nine out of ten females of test group 3 (versus two control females) showed a mostly minimal or slight multifocal mineralization in the papillae. A treatment-related effect could not be ruled out, but was considered to be non-adverse.

Testes: In the testes, a “diffuse” tubular degeneration was observed in males of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). The decrease of the absolute testes weight in males of test group 3 (450 mg/kg bw/d) was related to the diffuse tubular degeneration.

Epididymides: Oligospermia (mostly severe) was observed in the epididymes of nine males of test group 3 450 mg/kg bw/d. The oligospermia was linked to the decreased absolute and relative weights of epididymides.

Ovaries: In ovaries, vacuoles of different size were observed in the sex cord stroma in females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). Incidence and severity was dose-related increased. In addition, one female of test group 1 (50 mg/kg bw/d), one female of test group 2 (150
mg/kg bw/d) and all females of test group 3 (450 mg/kg bw/d) showed ovarian cysts. The occurrence of cysts in females of test group 3 (450 mg/kg bw/d) was assessed as treatmentrelated. The cysts in each one female of test groups 1 (50 mg/kg bw/d) and 2 (150 mg/kg bw/d) were considered to be rather incidental. Although there was no clear histopathological correlate for the decreased absolute and relative ovarian weights in females of test group 3 (450 mg/kg bw/d), a test substance-related effect cannot be ruled out.

Spleen: Incidence and graded severity of extramedullary hematopoiesis were increased in a dose-related manner in males and females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). In addition, the females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) showed an increased severity of hemosiderin storage. The increased relative spleen weights in males of test group 3 (450 mg/kg bw/d) as well as in females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) were associated with these findings.

Liver: The macroscopically diagnosed enlarged livers correlated with a minimal central hypertrophy in females that was observed in five females of test group 2 (150 mg/kg bw/d) as well as in nine females of test group 3 (450 mg/kg bw/d). The increased liver weights in females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) were related to the hypertrophy. No histopathological correlate was found for the enlarged livers in males. Fatty change of hepatocytes was observed in two males of test group 1 (50 mg/kg bw/d), in 8 males of test group 2 (150 mg/kg bw/d), and in 7 males of test group 3 (450 mg/kg bw/d). The fatty change was located peripheral in all affected males of test groups 1 (50 mg/kg bw/d) and 2 (150 mg/kg bw/d), as well as in two males of test group 3 (450 mg/kg bw/d). The other five males of test group 3 (450 mg/kg bw/d) showed a central fatty change. In most affected males, the fatty change was minimal. The macroscopically observed prominent acinar pattern was correlated in most males with fatty change. Glandular stomach: Two of the macroscopically diagnosed erosions or ulcers in the glandular stomach could be confirmed microscopically. In the glandular stomach, erosions or ulcers were observed in one control male and in three males of test group 3 (450 mg/kg bw/d). Mesenteric lymph nodes: The macroscopically observed red discoloration of the mesenteric lymph nodes corresponded histopathologically with sinus erythrocytosis. Sinus erythrocytosis occurred in the mesenteric lymph node of one female in test group 2 (150 mg/kg bw/d; minimal) and of one male and three females in test group 3 (450 mg/kg bw/d; slight). Thymus: A slight or moderate reduced cellularity was observed in the cortex of two males and one female in test group 3 (450 mg/kg bw/d). The reduced cellularity of the cortex fit to the reduced thymus weights and was considered to be a consequence of the body weight reduction. All additional findings: Occurred either individually or were biologically equally distributed over the control group and the treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.

In test group 3 (450 mg/kg bw/d), erosions or ulcers occurred in the forestomach of three males and of one female. In the glandular stomach, erosions/ulcers were observed in three males of test group 3 (450 mg/kg bw/d) in comparison to one male. A test substance-related effect could not be ruled out.
Intrasinusoidal erythrocytes (sinus erythrocytosis) occurred in the mesenteric lymph nodes of one female (minimal) in test group 2 (150 mg/kg bw/d) and of one male and three females (slight) in test group 3 (450 mg/kg bw/d). Intrasinusoidal erythrocytes (sinus erythrocytosis) can result from a lymph node, which drains a region of hemorrhage. This can also be an artifact that results from issue dissection during necropsy.


HISTOPATHOLOGY: NEOPLASTIC (if applicable) No

HISTORICAL CONTROL DATA (if applicable) No

DECEDENTS
One male (No. 32) of test group 3 (450 mg/kg bw/d) was sacrificed in a moribund state.
Severe meningitis was observed in the brain, a spermatogenic granuloma was noted in the
right epididymis, and an erosion/ ulcer occurred in the glandular stomach. Another male (No.
37) of test group 3 (450 mg/kg bw/d) died prematurely. This male showed a severe alveolar
histiocytosis in the lungs, a moderate purulent inflammation of the trachea and an erosion/
ulcer in the glandular stomach. The premature death of these two males was considered to
be incidental.
One female of test group 2 (No. 126, 150 mg/kg bw/d) was sacrificed during parturition. One
dead fetus was found in the right uterus horn and birth channel. No more fetuses were
detected. An influence of the test substance cannot be ruled out.

Effect levels

1

Dose descriptor:

LOAEL

Effect level:

50 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

2

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 8: Absolute organ weights   Male animals Female animals Test group (mg/kg bw/day) 1 (50) 2 (150 3 (450) 1 (50) 2 (150 3 (450) Terminal body weight 101% 96% 86%** 95% 93%** 85%** Adrenal glands       96% 90% 82%** Brain       99% 100% 96%* Epididymides 100% 90% 68%**       Liver 113%* 121%** 129%** 105% 123%** 124%** Ovaries       97% 99% 74%** Testes 103% 105% 78%**       Thymus 98% 92% 67%** 88% 83%* 69% * : p ≤ 0.05; **: p ≤ 0.01 Table 9: Relative organ weights   Male animals Female animals Test group (mg/kg bw/day) 1 (50) 2 (150 3 (450) 1 (50) 2 (150 3 (450) Adrenal glands 104% 102% 128%*       Brain 98% 104% 114%* 104%* 107%* 113%** Epydidymides 94% 98% 80%**       Heart 96% 106%* 122%** 98% 105%* 116%** Kidney 101% 110%* 126%** 108% 116%** 132%** Liver 111%** 127%** 150%** 111%** 133%** 146%** Ovaries       102% 106% 86%* Seminal vesicle 104% 113%* 117%*       Spleen 102% 111% 144%** 102% 112%* 121%** Testes 101% 110%* 91%       Thymus 97% 96% 79%*       * : p ≤ 0.05; **: p ≤ 0.01 Table 10: Histopathology   Male animals Female animals Test group (mg/kg bw/day) 1 (50) 2 (150 3 (450) 1 (50) 2 (150 3 (450) Kidneys Multifocal tubular degeneration   Multifocal tubular degeneration   increased rel kidney weight   increased rel kidney weight  Testes   diffuse tubular degeneration       decreased abs testis weight Epididymides   Oligospermia       Decreased abs epididymides weight, incidental Decreased abs/rel epididymides weight Ovaries       Ovarian cysts incidental Ovarian cysts vacuolization sex cord stroma decreased abs/rel ovary weight Spleen   extramedullary hematopoiesis   extramedullary hematopoiesis; hemosiderin storage increased rel spleen weight increased rel spleen weight Liver fatty change of hepatocytes   minimal central hypertrophy increased abs/rel liver weight increased abs/rel liver weight (rel only at low dose) enlarged livers enlarged livers acinar pattern     Fore- or glandular stomach     Erosions or ulcers     Erosions or ulcers Mesenteric lymph node     Sinus erythrocytosis   Sinus erythrocytosis red discoloration Thymus     reduced cellularity of cortex     reduced cellularity of cortex     decreased abs/rel thymus weight    decreased abs thymus weight

Applicant's summary and conclusion

Conclusions:

Under the conditions of the present reproduction/developmental toxicity screening test, the NOAEL for general, systemic toxicity of the test substance was 50 mg/kg bw/d for females and less than 50 mg/kg bw/d for male animals based on the tubular degeneration in the kidneys of six males.

Executive summary:

Methylaminoethanol was administered orally via gavage to groups of 10 male and 10 female Wistar rats (F0 animals) at dose levels of 50, 150 and 450 mg/kg bw/d.

The objective of the study was to detect possible effects of the test substance on the integrity and performance of the reproductive system of both sexes. Furthermore, it was intended to obtain information about the general toxicological profile including target organs and the no observed adverse effect level (NOAEL) after repeated oral administration. Control animals were dosed daily with the vehicle (highly deionized water). The duration of treatment covered a 2-week pre-mating and mating period in both sexes, approximately 1 week post-mating in males, and the entire gestation period as well as 4 days of lactation in females.

Regarding clinical examinations, signs of general systemic toxicity were only observed at a dose level of 450 mg/kg bw/d as there were significantly lower body weights in male and female parental animals accompanied with reduced food consumption and reduced general condition in single animals in several phases of the study. Reduced food consumption and body weights during gestation in females of test group 2 (150 mg/kg bw/d) were most likely related to implantation losses.

One male animal of test group 3 (450 mg/kg bw/d) showed temporarily clonic convulsions. Detailed clinical examinations in an open field, detailed observations in a functional observational battery (FOB) and measurements of motor activity did not reveal indications of test substance-induced effects in low, mid and high-dose rats. Therefore, the clonic convulsions were assessed as being incidental.

Salivation was seen after dosing in all high-dose rats. From the temporary, short appearance immediately after dosing it is likely, that this finding was induced by a bad taste of the test substance or local affection of the upper digestive tract. Urine discoloration was also observed for all high-dose rats which was most likely related to the test compound. However, both types of findings were not considered to be adverse, toxicologically relevant effects.

The deviated levels of clinical chemistry and haematology parameters pointed to anemia and changed liver cell metabolism. The total protein and the albumin levels were significantly higher in female rats starting at test group 1 (50 mg/kg bw/d). As these were the only deviating parameters in females of this test group the changes were regarded as treatment-related, but non-adverse. The reason for the increase of the sodium concentrations in rats of both sexes in test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) remains unclear, but a test substance-related effect could not be excluded. The higher incidences of leucocytes in the urine of rats of both sexes in test group 3 (450 mg/kg bw/d) and, additionally, in males of the test group 2 (150 mg/kg bw/d) as well as the increased incidence of higher transitional cell counts in males of test group 3 (450 mg/kg bw/d) can be regarded as signs of an affection of the urinary tract in treated rats.

Regarding pathology, after administration of the test substance the terminal body weight was significantly lower in females of test group 2 (150 mg/kg bw/d) and in males and females of test group 3 (450 mg/kg bw/d). The body weight reduction resulted in weight changes of adrenal glands, brain, heart, seminal vesicle, and thymus. Target organs were the kidney, spleen and liver (discussed here) and the testes, epididymides and ovaries. In kidneys, tubular degeneration was dose dependent and assessed as an adverse effect. In the spleen, a dose-related increase in incidence and severity of extramedullary hematopoiesis occurred in males and females of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). In addition, in females of these test groups the severity of hemosiderin storage was increased. These findings are associated with the increased relative spleen weights in females of test group 2 (150 mg/kg bw/d) as well as in males and females of test group 3 (450 mg/kg bw/d). They were induced in response to anaemia and related to treatment. The liver weights were dose-related increased in males and females of all treatment groups. The liver was enlarged in three males and one female of test group 2 (150 mg/kg bw/d) as well as in three males and five females of test group 3 (450 mg/kg bw/d). In females, the liver enlargement correlated with a minimal central hepatocellular hypertrophy that was observed in five animals of test group 2 (150 mg/kg bw/d) and in 9 animals of test group 3 (450 mg/kg bw/d). In males, mainly a minimal fatty change of hepatocytes was observed in two animals of test group 1 (50 mg/kg bw/d), in 8 animals of test group 2 (150 mg/kg bw/d), and in 7 animals of test group 3 (450 mg/kg bw/d). The liver findings were related to treatment and considered to be adaptive. Although, there were no clear histopathological correlates for the increased liver weights in males of all treatment groups and in females of test group 1 (50 mg/kg bw/d), a test substance-related effect could not be ruled out. There was no correlation between erosion/ ulcer in the stomach and erythrocytosis of the mesenteric lymph node (findings occurred in different animals). However, a treatment-related effect could not be ruled out but was assessed as non-adverse. All further findings occurred either singly or were biologically equally distributed over the control group and the treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.