Cysteine hydrochloride

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Principles of method if other than guideline:

Rats were randomly divided into experimental groups, each consisting of 50 males and 50 females.
The dose levels used were chosen on the basis of the results of a preliminary 12 week experiment.
Group I was given 0.5 % L-cysteine monohydrochloride (LCM), and group II 0.25 % LCM in their dr
inking water, while control group III was given tap water only. The feed and drinking water with and without LCM, were freely available. The rats were weighted every week and their water consumption was recorded every week for the first 13 weeks of the study and therefore once every 4 weeks. Blood samples were taken from all surviving rats of both sexes from each dosage group at week 108 for biochemical studies and hematology. Rats which died spontaneously or were killed when becoming moribund during the study, as well as those sacrificed at the end of the study, were autopsied and examined macro- and microscopically for the development of neoplastic and non-neoplastic lesions.
The autopsy included examination of the brain, spinal cord, salivary, pituitary and thyroid glands
(including parathyroid), thymus, lungs (including trachea), heart, oral cavity and tongue, esophagus, stomach, duodenum, jejunum, ileum, caecum, solon, rectum, liver, pancreas, spleen, adrenal glands, lymph nodes, skin, preputial/clitoral gland, ear duct, eyes and Haderian glands, musculature, sternum, femur, and nasal cavity. All organs, tissues, and lesions were fixed with 10 % buffered formalin, processed for wax embedding and sectioned. The sections were routinely stained with hematoxylin and eosin, other specific stains being used when necessary. The data were evaluated by the Wilcoxon-test or chi-square-test.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

L-Cysteine Hydrochloride Monohydrate

Cas Number:

175.63

Molecular formula:

C3H7NO2S·HCl·H2O

IUPAC Name:

L-Cysteine Hydrochloride Monohydrate

Test material form:

solid: granular

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

108 weeks

Frequency of treatment:

continuously

No. of animals per sex per dose:

50

Results and discussion

Effect levels

Dose descriptor:

NOAEL

Effect level:

13 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

histopathology: non-neoplastic

organ weights and organ / body weight ratios

water consumption and compound intake

Target system / organ toxicity

Critical effects observed:

yes

Lowest effective dose / conc.:

13 mg/kg bw/day (nominal)

System:

urinary

Organ:

kidney

Treatment related:

yes

Dose response relationship:

yes