3,5-diiodothyronine

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Based on the study conducted according to OECD 471 the test substance is not mutagenic.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10/07/2018 - 19/07/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 97

Details on mammalian cell type (if applicable):

TA97a

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium TA 102

Species / strain / cell type:

S. typhimurium TA 1535

Metabolic activation:

with and without

Test concentrations with justification for top dose:

The following nominal concentrations were prepared for the first experiment:
5000 µg/plate, 1500 µg/plate, 500 µg/plate, 150 µg/plate and 50 µg/plate

The following nominal concentrations were prepared for the second experiment:
5000 µg/plate, 2500 µg/plate, 1250 µg/plate, 625 µg/plate, 313 µg/plate and 156 µg/plate

Untreated negative controls:

other:

Remarks:

solvents: DMSO and water

Negative solvent / vehicle controls:

yes

Remarks:

solvents: DMSO and water

Positive controls:

yes

Positive control substance:

sodium azide

benzo(a)pyrene

other: nitrophenylendiamin and 2-amino-anthracene

Details on test system and experimental conditions:

Eight hours before the start of each experiment, an aliquot of a permanent culture per strain to be used was taken from the deep freezer to inoculate a culture vessel containing nutrient broth. After incubation overnight for eight hours at 37 ± 1 °C, the cultures were used in the experiment. During the test, the cultures were stored at room temperature as to prevent changes in the titre.

Key result

Species / strain:

S. typhimurium TA 97

Remarks:

TA97a

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

Based on the results of this study it is concluded that L-Tyrosine, O-(4-hydroxyphenyl)-3,5-diiodo- is not mutagenic in the Salmonella typhimurium strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.

Executive summary:

The test itemL-Tyrosine, O-(4-hydroxyphenyl)-3,5-diiodo-showed no increase in the number of revertants in all bacteria strains in both experiments.

All negative and all strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available