4-nitrotoluene

Carcinogenicity

Administrative data

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

2002

Reference 2

Reference Type:

secondary source

Title:

4-Nitrotoluene - CAS N°: 99-99-0 - SIDS Initial Assessment Report.

Author:

OECD

Year:

2003

Bibliographic source:

UNEP Publications

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Deviations:

yes

Remarks:

no interim kill was performed and no hematology data or clinical chemistry data were noted

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-nitrotoluene

EC Number:

202-808-0

EC Name:

4-nitrotoluene

Cas Number:

99-99-0

Molecular formula:

C7H7NO2

IUPAC Name:

1-methyl-4-nitrobenzene

Details on test material:

- Name of test material (as cited in study report): p-nitrotoluene
- Physical state: clear, pale yellow, crystalline solid
- Analytical purity: > 99%
- Lot/batch No.: 338297/1495
- Stability under test conditions: Stability studies of bulk chemical were performed by Midwest Research Institute (Kansans City, MO, USA) using gas chromatography. No degradation of the bulk chemical was observed after storage for two weeks, protected from light, at temperature up to 60°C
- Storage condition of test material: To ensure stability, the bulk chemical was stored at approximately 5°C in sealed containers. Stability was monitored during the 2-year studies using gas chromatography. No degradation of the bulk chemical was detected.
- Source: St.Louis, MO, USA

Test animals

Species:

rat

Strain:

other: F344/N

Sex:

male/female

Details on test animals or test system and environmental conditions:

ANIMALS PER CAGE: 2 or 3 (males) or 5 (females)
TIME HELD BEFORE STUDIES: 12 days AVERAGE AGE WHEN STUDY BEGAN: 5-6 weeks
DURATION OF EXPOSURE: 105-106 weeks AVERAGE AGE AT NECROPSY: 111 to 112 weeks
DIET: NTP-2000 Open Formula meal, available ad libitum; rats received nonirridiated feed from the beginning of the studies for 8 months and irradiated feed to the end of the studies. WATER: tap water, available ad libitum
ANIMAL ROOM ENVIRONMENT: temperature: 72°F; relative humidity: 50% ± 15%; room fluorescent light: 12 hours/day; room air changes: 10 hour

Administration / exposure

Route of administration:

oral: feed

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

105 -106 weeks

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 1250, 2500, 5000 ppm |(males: approx. 0, 55, 110, 240 mg/kg bw)|(females: approx. 0, 60, 125, 265 mg/kg bw)
Basis:
nominal in diet

No. of animals per sex per dose:

50

Control animals:

yes, plain diet

Details on study design:

Post-exposure period: no

Examinations

Observations and examinations performed and frequency:

TYPE AND FREQUENCY OF OBSERVATION: Observed twice daily, rats were weight initially, during week 4, and every 4 weeks thereafter; clinical findings were recorded at 4-week intervals, feed consumption was measured over a 1-week period every 4 weeks
METHOD OF SACRIFICE: Carbon dioxide asphyxisation
URINALYSIS: Urine was collected during a 24-hour period from 5 male and 5 female rats from each group at 2 weeks and 3, 12, and 18 months. Parameters evaluated included urine volume, creatinine, p-acetamidobenzoic acid and p-nitrobenzoic acid.

Sacrifice and pathology:

NECROPSY: Necropsy was performed on all animals
HISTOPATHOLOGY: Complete histopathology was performed on all animals. In addition to gross lesions and tissue masses, the following tissues were examined: adrenal gland, bone, brain, clitoral gland, esophagus, heart and aorta, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, liver, lung and mainstem bronchi, lymph nodes (mandibular and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis with epididymis and seminal vesicle, thymus, thyroid gland, trachea, urinary bladder, and uterus
URINALYSIS: Urine was collected during a 24-hour period from 5 male and 5 female rats from each group at 2 weeks and 3, 12, and 18 months. Parameters evaluated included urine volume, creatinine, p-acetamidobenzoic acid and p-nitrobenzoic acid.
Haematology or clinical chemistry was not performed.

Statistics:

Poly-k test, continuity corrected Poly-3 test, Fisher's least significant difference test, Mann-Whitney U test

Results and discussion

Any other information on results incl. tables

Survival rate (0 ppm, 1250 ppm, 2500 ppm, 5000 ppm):
males: 31/50, 38/50, 38/50, 40/50;females: 39/50, 37/50, 39/50, 41/50

Mean body weights at the end of the study (control, low, mid, high dose):
males: 402 g, 409 g, 402 g, 366 g (91 % of controls);females294 g, 272 g, 262 g, 210 g.

Clinical signs of toxicity:
all exposed male and female rats showed nasal- and eye discharge

Haematology data or clinical chemistry data were not reported

Non-Neoplastic effects (control, low, mid, high dose):
Kidney:
renal tubule hyaline droplet, m: 2/50, 23/50, 27/50, 18/50 f: 8/50, 41/50, 49/50, 46/50; renal tubule pigmentation, m: 10/50, 28/50, 47/50, 46/50 f: 9/50, 43/50, 49/50, 50/50; mineralization, f: 15/50, 21/50, 32/50, 40/50; oncocytic renal tubule hyperplasia, f: 0/50, 2/50, 4/50, 6/50

Spleen: hemapoietic cell proliferation, m: 9/50, 13/50, 19/50, 25/50 f: 26/50, 26/50, 45/50, 43/50; pigmentation, m: 10/50, 12/50, 24/50, 38/50 f: 24/50, 32/50, 45/50, 48/50;

Liver:
basophilic focus, m: 31/50, 39/50, 42/50, 45/50; clear cell focus, m: 20/50, 27/50, 30/50, 32/50; eosinophilic focus, m: 5/50, 5/50, 5/50, 9/50 f: 1/50, 2/50, 7/50, 9/50;

Testis:
germinal epithelial atrophy, m: 7/50, 11/50, 8/50, 30/50

Neoplastic effects (control, low, mid, high dose):
Clitoral gland:
adenoma or carcinoma, f: 8/50, 12/50, 20/50 (sign.), 8/50
(historical control: 84/636 = 13.2 %, range: 2-24 %)

Skin (subcutaneous):
fibroma, m: 1/50, 2/50, 7/50, 1/50 (historical control: 33/609 = 5.4 %, range: 0-12%);
fibroma or fibrosarcoma, m: 1/50, 2/50, 9/50, 1/50 (historical control: 41/609 =m 6.7 %, range: 2-14%)

Mononuclear cell leukemia:
m: 24/50, 12/50, 5/50, 4/50 f: 13/50, 12/50, 3/50, 1/50

Testis
interstitial cell adenoma, m: 49/50, 46/50 45/50 34/50