2-ethylaminoethanol

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: combined study (repeated dose and reproduction/developmental toxicity screening)

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study

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

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

Test material form:

other: liquid

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: 11-13 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

IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on 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

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: overnight starting at 13 days after the beginning of treatment to produce litter (F1 generation pups). Mating pairs were from the same test group. Mating was discontinued as soon as sperm was detected in the vaginal smear.
- Proof of pregnancy: [sperm in vaginal smear] referred to as [day 0 ] of pregnancy
- Further matings after two unsuccessful attempts: [no]
- After successful mating each pregnant female was caged ( Pregnant females were provided with nesting material (cellulose wadding) toward the end of pregnancy.):
- Any other deviations from standard protocol: no

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

Details on study schedule:

See details in section 7.5.1:
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. Age at mating of the mated animals in the study: 13-14 weeks
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 selected 5 female animals (with litter) 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.

Doses / concentrations

Remarks:

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

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

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

Positive control:

no

Examinations

Parental animals: Observations and examinations:

See section 7.5.1 for details:

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
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).

Oestrous cyclicity (parental animals):

not examined

Sperm parameters (parental animals):

Sperm parameters not examined; only parameters examined in [P] male parental generations: testis weight, epididymis weight

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in [F1] offspring:
[number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities, other:] viability index was calculated as follows: (number of live pups on PND4/number of liveborn pups on the day of birth)x100. The same for sex ratio: (number of live male or female pups on day 0/ 4/number of live male and female pups on day 0/ 4)x100
The live pups were examined daily for clinical symptoms (including gross-morphological findings) during the clinical inspection of the dams.
The pups were weighed one day after birth (PND 1) and on day 4 after birth.

GROSS EXAMINATION OF DEAD PUPS:
[ yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead.]

Postmortem examinations (parental animals):

Reproductive organs: After sacrifice of the female animals the uterus and ovaries were removed and theimplantation sites were counted. To determine the number of implantation sites in apparentlynon-pregnant animals, the uteri from those females were stained in 10% ammonium sulfidesolution for about 5 minutes according to the method of Salewski.Then, the respective uteri were rinsed carefully with fresh tap water. The implantation siteswere recorded for the calculation of the postimplantation loss (considered as a developmental endpoint in section 7.8.2). Reproductive organ weights/histopathology performed: male (testis, epididymis, seminal vesicle, prostrate), female (ovaries)

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals and were sacrificed at [4] days of age. All surviving pups (after sacrifice on PND 4 by means of CO2), all stillborn pups and those pups that died before schedule, were examined externally, eviscerated and their organs were assessed macroscopically. All pups without any notable findings or abnormalities were discarded after their macroscopic
evaluation.
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows: all gross lesions, lungs and spinal cord (cervical, thoracic and lumbar cord) were preserved in neutrally buffered 4 % formaldehyde solution and then analyzed.

GROSS NECROPSY
- Gross necropsy consisted of [external and internal examinations including the cervical, thoracic, and abdominal viscera.]

HISTOPATHOLOGY / ORGAN WEIGTHS
The tissues were prepared for microscopic examination and weighed, respectively.

Statistics:

Body weight and body weight change (for the pup weights, the litter means were used) number of mating days, duration of gestation, number of pups delivered per litter, implantation sites, post implantation loss: DUNNETT-test (two-sided)
Reproduction indices, females with stillborn pups, females with all stillborn pups, live birth index, pups stillborn, pups died, pups cannibalized, pups sacrificed moribund, viability index, number of litters with affected pups at necropsy : FISHER'S EXACT test

Reproductive indices:

Male mating index %: (number of males with confirmed mating* /number of males placed with females)x100; *- defined by a female with vaginal sperm or with implants in utero;
Male fertility index (%): (number of males proving their fertility */number of males placed with females)x100; * - defined by a female with implants in utero;
Female mating index (%): (number of females mated */ number of females placed with males)x100; * - defined as the number of females with vaginal sperm or with implants in utero;
Female fertility index (%): (number of females pregnant */number of females mated **)x100; * defined as the number of females with implants in utero; ** defined as the number of females with vaginal sperm or with implants in utero.
Gestation index (%): (number of females with live pups on the day of birth/number of females pregnant *); * - defined as the number of females with implants in utero;
Live birth index(%): (number of liveborn pups at birth/total number of pups born)x100;
Post implantation loss (%): (number of implantations number of pups delivered/number of implantations)x100

Offspring viability indices:

Viability index (%): (number of live pups on PND4/number of liveborn pups on the day of birth)x100. The same for sex ratio: (number of live male or female pups on day 0/ 4/number of live male and female pups on day 0/ 4)x100

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:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): With regards to findings during gestation and lactation: 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. Findings were only seen in test group 3 (450 mg/kg bw/d), i.e. poor general state was observed in 4 female animals (animal nos. 132, 135, 136 and 140) from GD 11 onwards, salivation after treatment was observed in 2 female animals (animal nos. 136 and 139) from GD 2 onwards and discolored urine was observed in all animals during the whole gestation period. No test substance-related clinical findings occurred in the female animals in any dose group during lactation.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS): see section 7.5.1 for general findings.
With regards to findings during gestation and lactation:
During gestation body weights of female animals of test group 2 (150 mg/kg bw/d) were
significantly lower on GD 14 and 20 and of test group 3 (450 mg/kg bw/d) body weight was
even decreased on GD 20.
Body weight changes of female animals during gestation were significantly lower between
GD 0-7 in test group 1 (50 mg/kg bw/d) as well as between GD 0-7 and GD 7-14 in test group
2 (150 mg/kg bw/d). A body weight loss could be detected between GD 14-20 in test groups
2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d). Consequently, the overall body weight change
between GD 0-20 was also significantly lower for these test groups.
Body weights and body weight changes of female animals treated with 50 mg/kg bw/d were
not significantly changed during lactation. During lactation, a comparison of body weight data
of test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) to the control were not meaningful
as only one litter consisting of one stillborn pup existed in test group 2 (150 mg/kg bw/d) and
no pups were alive in test group 3 (450 mg/kg bw/d).
During the post-weaning period female body weights were significantly lower in test groups 2
(150 mg/kg bw/d) and 3 (450 mg/kg bw/d) in study week 6 and 7. The same was true for
females of test group 1 (50 mg/kg bw/d) in study week 7. As the terminal mean body weight
in this test group was unaffected. Absolute organ weights) this change was assessed as incidental
and not related to treatment.

During gestation the food consumption in test group 2 (150 mg/kg bw/d) was significantly
decreased between GD 14 and 20.
During lactation food consumption in test group 2 (150 mg/kg bw/d) was significantly lower
compared to the control.


TEST SUBSTANCE INTAKE (PARENTAL ANIMALS) not applicable

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS) not examined

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS) not examined

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)

The male mating index was 100% in all test groups. Fertility was proven for most of the F0 parental males of test groups 0 (control) and 1 (50 mg/kg bw/d) within the scheduled mating interval for the F1 litter. One control male and one male of test group 1 did not generate F1 pups. Furthermore, six males of test group 2 and nine males of test group 3 did not generate F1 pups. Thus, the male fertility index ranged between 11% and 90% (see Tab.4 ). For test groups 0 (control) and 1 (50 mg/kg bw/d) these findings reflected the normal range of biological variation inherent in the strain of rats used for this study as all respective values were within the range of the historical control data. With regard to pathological findings in epididymidis and testis, the test substance did adversely affect reproduction of the F0 males in test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d).
The female mating index calculated after the mating period for F1 litter was 100% for all test groups. The mean duration until sperm was detected (GD 0) amounted to 2.4, 1.4, 2.5, and 2.9 days (0, 50, 150 and 450 mg/kg bw/d, respectively). Consequently, the differences between the test groups were assessed as being spontaneous in nature and without biological relevance. All sperm-positive rats of test groups 0 (control) and 1 (50 mg/kg bw/d) delivered pups or had implantations in utero with the following exceptions: one female (test group 0) and one female (50 mg/kg bw/d) did not become pregnant. 6 females of test group 2 (150 mg/kg bw/d), and 9 females of test group 3 (450 mg/kgbw/d) did not become pregnant. The fertility index varied between 10% and 90% (Tab. 5).
Implantation was not affected by the treatment in test group 1 (50 mg/kg bw/d) since the
mean number of implantation sites was comparable test group 0 (0 mg/kg bw/d). In test
groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d) a significant reduction with only 5 and 1
implantation sites was found.The mean duration of gestation, i.e. 22.1 and 22.2 days, was similar in test groups 0 (control)
and 1 (50 mg/kg bw/d). No parturition was seen in test group 2 (150 mg/kg bw/d) except of
female No. 126 which was sacrificed on GD 23 because of an inability to deliver. Gestation
length was not calculable for test group 3 (450 mg/kg bw/d).
The gestation index varied between 89% (control group) and 100% (50 mg/kg body
weight/day). All values seen in test groups 0 (control) and 1 (50 mg/kg bw/d) reflect the normal range of
biological variation inherent in the strain of rats used for this study. All respective values were
within the range of the historical control data and did not show a relation to dosing. However, a clear relation
to dosing was obtained for test groups 2 (150 mg/kg bw/d) and 3 (450 mg/kg bw/d).
The mean number of F1 pups delivered per dam was not affected in test group 1 (50 mg/kg
bw/d) whereas only one pup was delivered in test group 2 (150 mg/kg bw/d) and none in test
group 3 (450 mg/kg bw/d).
The rate of liveborn pups was unaffected in test group 1 (50 mg/kg bw/d) and the live birth
index was 96%. The rate of stillborn pups was not significantly different compared to the
control group and within the range of the historical control data. In test group 2 (150 mg/kg bw/d) the
live birth index was 0 because only one stillborn pup was delivered.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: fertility, reproductive performance

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

no effects observed

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Details on results (F1)

VIABILITY (OFFSPRING):

The mean number of delivered pups per dam and the rate of liveborn and stillborn pups were
evenly distributed among test groups 0 (control) and 1 (50 mg/kg bw/d). The respective
values reflect the normal range of biological variation inherent in the strain used in this study.

The viability index as indicator for pup mortality between PND 0-4 was 100% for test groups
0 (control) and 1 (50 mg/kg bw/d). No viable pups were observed in test group 2 (150 mg/kg
bw/d) and test group 3 (450 mg/kg bw/d).

CLINICAL SIGNS (OFFSPRING):

The F1 pups did not show adverse clinical signs up to scheduled sacrifice on PND 4. In one
litter (dam No. 112 of test group 1) one pup showed a papilloma-like a skin flap. This single
observation was considered to be spontaneous in nature and not to be adverse.

BODY WEIGHT (OFFSPRING):

Mean pup body weights/pup body weight changes of all pups in test group (50 mg/kg bw/d)
were comparable to the concurrent control values. The observable differences between the
groups were assessed as being spontaneous in nature and without biological relevance.
One runt of each gender was seen in test group 0 (control) and 5 female runts were seen in
test group 1 (50 mg/kg bw/d). Both values were within the range of the biological variation
inherent in the strain of rats used for this study.

SEXUAL MATURATION (OFFSPRING): not applicable

ORGAN WEIGHTS (OFFSPRING): not examined

GROSS PATHOLOGY (OFFSPRING):

One stillborn pup of test group 1 (50 mg/kg bw/d) showed post mortem autolysis. In 3 pups of
test group 1 (50 mg/kg bw/d) and in the single stillborn pup of test group 2 (150 mg/kg bw/d)
the stomach was found empty.

HISTOPATHOLOGY (OFFSPRING): no treatment-related effects in low dose group

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Table 4: Reproductive performance (male animals)

	Test group 0 (0 mg/kg bw/d)	Test group 1 (50 mg/kg bw/d)	Test group 2 (150 mg/kg bw/d)	Test group 3 (450 mg/kg bw/d)
Male fertility index [%]	90	90	40	11**

Table 5: Reproductive performance (female animals)

	Test group 0 (0 mg/kg bw/d)	Test group 1 (50 mg/kg bw/d)	Test group 2 (150 mg/kg bw/d)	Test group 3 (450 mg/kg bw/d)
Female fertility index [%]	90	90	40*	10**

* p ≤ 0.05; ** p ≤ 0.01

Applicant's summary and conclusion

Conclusions:

Under the conditions of the present reproduction/developmental toxicity screening test the NOAEL (no observed adverse effect level) for reproductive performance and fertility was 50 mg/kg bw/d for the parental rats.

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.

Fertility was severely impaired by test-substance administration at dose levels of 150 and 450 mg/kg bw/d. Although mating (male and female mating indices) was not influenced no lifeborn pups were delivered for both test groups.

Target organs were the kidney, liver and spleen (discussed in section 7.5.1) and the testes, epididymides and ovaries. In testes, tubular degeneration was dose dependent and assessed as an adverse effect. In ovaries, the occurrence of cysts and vacuolization of sex cord stroma was related to treatment and was considered to be adverse. In test group 3 (450 mg/kg bw/d), the infertility was linked to the reduced number of sperms (oligospermia) caused by tubular degeneration in testes. In addition, the occurrence of ovarian cysts and vacuolization of the sex cord stroma in females may have influenced the fertility. In test group 2 (150 mg/kg bw/d), the severity of the findings in testes or ovaries was only minimal or slight and the findings did not occur in all infertile animals. Nevertheless, these lesions may have affected fertility.