Urea

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published public domain study, similar to guidelines

Data source

Reference

Reference Type:

publication

Title:

The results of microbial mutation test for forty-three industrial chemicals

Author:

Shimizu, H., Suzuki, Y., Takemura, N., Goto, S. & Matsushita, H.,

Year:

1985

Bibliographic source:

Japanese Journal of Industrial Health 27(6): 400-19

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Principles of method if other than guideline:

Preincubation method

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Urea

EC Number:

200-315-5

EC Name:

Urea

Cas Number:

57-13-6

Molecular formula:

CH4N2O

IUPAC Name:

urea

Details on test material:

Purity: 99 %. Source: Wako Pure Chemical Industries, Ltd., Osaka, Japan

Method

Target gene:

No information available

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not applicable

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Additional strain / cell type characteristics:

not applicable

Species / strain 3

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9 - liver of male Sprague-Dawley rats, pretreated with polychlorinated biphenyl (KC500) at 500mg/kg bw 5 days before sacrifice. Mix: 0.1ml of S9/ml

Test concentrations with justification for top dose:

5, 10, 50, 100, 500, 1000 and 5000 µg/plate

Vehicle / solvent:

Water

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-(2-Furyl)-3-(5-nitro-2-furyl) acrylamide

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoantracene

Details on test system and experimental conditions:

The preincubation method was used. 0.1ml bacterial strain and 0.5ml of S9 mix or sodium phosphate buffer (pH 7.4) were added to a sterile test tube containing 0.1ml of urea at the test concentrations. The mixture was then preincubated in a shaker water bath at 37°C for 20 minutes, and then added to 2ml of molten top agar (45°C). The mixture was poured onto a minimal glucose agar plate immediately. The plated were incubated at 37°C for 48 hours.

Evaluation criteria:

The number of revertant colonies on each plate was scored with an automated colony counter.

Statistics:

No information available

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 6

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

No information available

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Urea did not show any mutagenicity in the Ames test with and without metabolic activation.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with and without activation

A negative result was observed in the Ames test, for urea with and without metabolic activation.

Executive summary:

The mutagenicity of urea was determined in the Ames test using Salmonella typhimurium and Escherischia coli bacteria, with and without S9 metabolic activation. The substance was not mutagenic at any of the 7 concentrations tested.