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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Justification for type of information:
The read-across is a category approach based on the hypothesis that compounds in this category are transformed to a common compound. This approach serves to use existing data on genotoxicity, repeated-dose toxicity, and reproductive toxicity endpoints for substances in this category.
There are no relevant variations in properties among source substances and the same potency is predicted for all target substances. This is Scenario 5 of the RAAF . Substances ATG, MEATG, KTG, CaTG, and NaTG are different inorganic salts of a common acid, thioglycolic acid (TGA; synonym: 2- mercaptoacetic acid). They dissociate rapidly in aqueous media, e.g., the test organism, to the common thioglycolate anion and to their different counter ions. The water solubility of all category members is high, except for CaTG which is only moderately soluble in water.
In the repeated-dose toxicity studies with NaTG, specific toxicity is exerted via the well-investigated inhibition of mitochondrial fatty acid beta-oxidation by the thioglycolate (2-mercaptoacetate) anion 2,3,4. Inhibition of beta-oxidation leads to increased triglycerides and decreased acetyl-CoA in liver, and subsequently reduced gluconeogenesis. The latter presents as hypoglycaemia in NaTGtreated rats, which is aggravated by fasting (Grosdidier, 2011; Report No. 37043 TSR). This mode of action (MoA) is thought to mediate the acute oral toxicity in fasted rats observed with all category members.
It can be predicted with high confidence that the target substances will display the same MoA and lead to the same effects seen with NaTG.

For more detailed information please refer to section 13.2.
Cross-reference
Reason / purpose for cross-reference:
read-across: supporting information

Data source

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
Ammonium mercaptoacetate
EC Number:
226-540-9
EC Name:
Ammonium mercaptoacetate
Cas Number:
5421-46-5
Molecular formula:
C2H4O2S.H3N
IUPAC Name:
ammonium 2-sulfanylacetate

Results and discussion

Effect levels

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Key result
Dose descriptor:
NOAEL
Effect level:
19 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical biochemistry
haematology
histopathology: non-neoplastic
mortality
Remarks on result:
other: corrected for molecular weight differences
Dose descriptor:
LOAEL
Effect level:
57 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical biochemistry
haematology
histopathology: non-neoplastic
mortality
Remarks on result:
other: corrected for molecular weight differences

Target system / organ toxicity

Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
57 mg/kg bw/day (actual dose received)
System:
hepatobiliary
Organ:
liver
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
not specified

Applicant's summary and conclusion

Conclusions:
Based on data for NaTG, the subchronic oral NOAEL of ATG is assumed to be 19 mg/kg bw/day.