Pyridine

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Reliable without restriction, guideline study by the U.S. National Toxicology Program

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Pyridine

EC Number:

203-809-9

EC Name:

Pyridine

Cas Number:

110-86-1

Molecular formula:

C5H5N

IUPAC Name:

pyridine

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

phosphate buffered saline (PBS)

Duration of treatment / exposure:

72 hours prior to sacrifice

Frequency of treatment:

3, every 24 hours prior to sacrifice

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
31.25 mg/kg bw
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
62.5 mg/kg bw
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
125 mg/kg bw
Basis:
nominal conc.

Doses / concentrations 4

Remarks:

Doses / Concentrations:
250 mg/kg bw
Basis:
nominal conc.

Doses / concentrations 5

Remarks:

Doses / Concentrations:
500 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

5

Control animals:

not specified

Positive control(s):

cyclophosphamide

Examinations

Tissues and cell types examined:

Bone marrow from femurs

Details of tissue and slide preparation:

. The animals were killed 24 hours after the third injection and blood smears were prepared from bone marrow cells obtained from the femurs. Air-dried smears were fixed and stained; 2000 polychromatic erythrocytes (PCEs) were scored for the frequency of micronucleated cells in each of five animals per dose group. In addition, the percentage of PCEs among the total erythrocyte population in the bone marrow was scored for each dose group as a measure of toxicity.

Evaluation criteria:

An individual trial was considered positive if the trend test P value was less than or equal to 0.025 or if the P value for any single dose group was less than or equal to 0.025 divided by the number of dose groups. A final call of positive for micronucleus induction was preferable based on reproducibly positive trials. Ultimately, the final call was determined by the scientific staff after considering the results of statistical analyses, the reproducibility of any effects observed and the magnitude of those effects.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

No increase in the frequency of micronucleated PCEs was noted in bone marrow after intraperitoneal injection of the test substance when administered up to 500 mg/kg three times at 24-hour intervals. The micronucleated PCEs per 1000 PCE and the percent PCEs in the treated groups were essentially identical to the control values.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Pyridine was administered intraperitoneally to male B6C3F1 mice at doses ranging from 62.25 to 500 mg/kg bw 72 hours prior to sacrifice in a micronucleus assay. No increase in the frequency of micronucleated PCEs was noted in bone marrow tissue.