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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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:
in vivo mammalian cell study: DNA damage and/or repair
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1993

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
Unscheduled DNA synthesis via induction ornithin decarboxylase
Single strand scission determined by an alkaline elution method.
GLP compliance:
not specified
Type of assay:
unscheduled DNA synthesis

Test material

Constituent 1
Chemical structure
Reference substance name:
2-methylhydroquinone
EC Number:
202-443-7
EC Name:
2-methylhydroquinone
Cas Number:
95-71-6
Molecular formula:
C7H8O2
IUPAC Name:
2-methylbenzene-1,4-diol
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
Fischer 344/DuCrj
Sex:
male

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
99% methylhydroquinone (no vehicle)
Duration of treatment / exposure:
once
Frequency of treatment:
once
Post exposure period:
48 h
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Dose / conc.:
90 mg/kg bw/day (nominal)
Dose / conc.:
200 mg/kg bw/day (nominal)
Dose / conc.:
250 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
No. of animals per sex per dose:
not given
Control animals:
yes
Positive control(s):
MNNG (N-methyl-N'-nitro-N-nitrosoguanidine)

Examinations

Tissues and cell types examined:
pyloric mucosa
Evaluation criteria:
Ornithine decarboxylase (ODC) and replicative DNA synthesis (RDS) as markers of tumor promotion,
DNA single strand scission and unscheduled DNA synthesis (UDS) as markers of tumor initiation.

Results and discussion

Test results
Key result
Sex:
male
Genotoxicity:
positive
Toxicity:
yes
Remarks:
low effects at 200 mg/kg bw
Vehicle controls validity:
not specified
Negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Methylhydroquinone showed very weak tumor-promoting activities and some tumor-initiating activities in the pyloric mucosa of rat stomach.
Executive summary:

In an in vivo study, tumor initiation and tumor promotion were investigated using methylhydroquinone as test item in the pyloric mucosa of male F344 rats. Methylhydroquinone showed very weak tumor-promoting activities and some tumor-initiating activities in the pyloric mucosa of rat stomach.

Ornithine decarboxylase (ODC) and replicative DNA synthesis (RDS) were used as markers of tumor promotion and DNA single strand scission and unscheduled DNA synthesis (UDS) as markers of tumor initiation.