L-threonine

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

L-threonine

EC Number:

200-774-1

EC Name:

L-threonine

Cas Number:

72-19-5

Molecular formula:

C4H9NO3

IUPAC Name:

L-threonine

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Between 8 and 12 weeks at the time of the administration
- Weight at study initiation: 203 - 217 g
- Fasting period before study: overnight
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: At least 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Average of 20.43 °C (continuous control and recording)
- Humidity (%): Average of 48.88 % (continuous control and recording)
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on oral exposure:

VEHICLE
A 0.1 % aqueous solution of Na-carboxymethylcellulose ("CMC" high viscosity, item No. C- 5013, Sigma) was used as vehicle for the test substance
MAXIMUM DOSE VOLUME APPLIED:
The dose volume was 10 mL per kg body weight. The individual dose volumes were calculated using lhe body weights determined on the day of the
administration
The dosing was performed sequentially to groups of 3 animals per step using a starting dose of 2000 mg per kg body weight.
The sequence of dosing of the lest substance was:
Step 1: 2000 mg per kg body weight.
Step 2: 2000 mg per kg body weight.

Doses:

2000 mg/kg b.w.

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

Observations were performed within the periods 0 - 0.5, 0.5 - 1, 1 - 2, 2 - 4 and 4 - 6 hours after administration (p.a.) of the test substance and
then at least once a day for a total of 2 weeks. Observations included but were not limited to changes in skin, fur, eyes, the occurrence of secretions and excretions, autonomic activity, changes in gait, posture and the presence of convulsions.
Body weights were determined: before administration, 7 days p.a., 14 days p.a.
Body weight gain was calculated for each week of the study, i.e. between 0 and 7 days p.a., 7 and 14 days p.a.

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived until the scheduled termination of the study

Clinical signs:

other: All animals did not show any clinical signs during the entire observation period.

Gross pathology:

No abnormal findings were made in all animals at the necropsy 14 d p.a.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

Migrated information

Conclusions:

No toxic effects of the test substance were noted by signs in life and post mortem in both steps at a dose of 2000 mg test substance
per kg body weight. No mortality occurred. Therefore the LD50, oral is definitely > 2000 mg/kg body weight.