Registration Dossier
Registration Dossier
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EC number: 200-157-7 | CAS number: 52-89-1
Carcinogenicity
Administrative data
Description of key information
In a cancerogenicity study rats were exposed to levels of 0, 0.25 % and 0.5 % L-Cysteine hydrochloride (0, 133/148 and 235/280 mg/kg bw. for males/females) in the drinking water for 108 weeks.
Histopathology revealed toxic effects on the kidneys, but no carcinogenic effects were observed.
Although no no-effect level was identified, the clear decline of toxic effects between the 2 dosages allows the estimation that a level of at least 13 mg/kg bw / day for both sexes should be a no-effect level.
Key value for chemical safety assessment
Carcinogenicity: via oral route
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LOAEL
- 130 mg/kg bw/day
- Study duration:
- chronic
- Species:
- rat
- Quality of whole database:
- One reliable study with detailed documentation of results. Sufficient animal numbers. The study is valid with restrictions.
- System:
- urinary
- Organ:
- kidney
Carcinogenicity: via inhalation route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Carcinogenicity: via dermal route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Justification for classification or non-classification
It can be concluded that L-Cysteine hydrochloride and L-Cysteine hydrochloride
monohydrate is not carcinogenic based on the available data.
According to Regulation (EC) No.: 1272/2008 and subsequent regulations, the L-Cysteine hydrochloride as well as the monohydrate form is not classified with regard to Carcinogenicity
Additional information
In a carcinogenicity study groups of 50 male and 50 female rats were exposed to levels of 0, 0.25 % and 0.5 % L-Cysteine hydrochloride (0, 133 and 235 mg/kg bw. for males and 0, 148 and 280 mg/kg bw. for females) in the drinking water for 108 weeks.
L-Cysteine hydrochloride caused the following changes:
0.25 % in drinking water:
males: no significant effect,
females: reduced body weights,
histopathology: necrosis of the renal papillae in 2 of 43 animals,
hyperlasia of the kidney pelvis in one animal.
0.5 % in drinking water:
males: reduced body weights
histopathology: focal necrosis of the proximal tubules 2 of 41 animals
females: reduced: body weights
histopathology: necrosis of the renal papillae in 6 of 38 animals,
hyperlasia of the kidney pelvis in one of 38 animals
calcification of the renal papillae in 2 of 38 animals
focal necrosis of the proximal tubules in one of 38 animals.
Although no no-effect level was identified, the clear decline of toxic effects between the 2 dosages allows the estimation that a level of at least 13 mg/kg bw /day for both sexes should be a no-effect level.
It was concluded that L-cysteine hydrochloride does not induce any neoplasms when given orally to Rats (F344/DuCrj) for 108 weeks.
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