Table 7.
Incidences of neoplasms and nonneoplastic lesions of the thyroid gland and nonneoplastic lesions of the nose in mice following 2-year treatment with GBE by oral gavage.
| Vehicle control | 200 mg/kg | 600 mg/kg | 2000 mg/kg | |
|---|---|---|---|---|
| Male | ||||
| Thyroid gland | ||||
| n | 49 | 49 | 50 | 50 |
| Follicle, hyperplasia | 2 (1.0) | 1 (1.0) | 7 (1.1) | 25** (1.4) |
| Follicular cell hypertrophy | 2 (1.0) | 0 | 2 (1.5) | 38** (1.2) |
| Follicular cell adenomaa | 0 | 0 | 2 (4%) | 2 (4%) |
| Nose | ||||
| n | 50 | 50 | 50 | 50 |
| Olfactory epithelium Accumulation hyaline droplet |
18 (1.4) | 16 (1.9) | 15 (1.8) | 28* (1.8) |
| Olfactory epithelium pigmentation |
0 | 1 (1.0) | 3 (1.0) | 13** (1.1) |
| Female | ||||
| Thyroid gland | ||||
| n | 50 | 48 | 49 | 48 |
| Follicular cell hypertrophy | 1 (3.0) | 5 (1.4) | 9* (1.0) | 39** (1.0) |
| Nose | ||||
| n | 50 | 50 | 50 | 50 |
| Olfactory epithelium Accumulation hyaline droplet |
5 (1.0) | 3 (1.7) | 12 (1.2) | 17** (1.6) |
| Olfactory epithelium pigmentation |
0 | 1 (1.0) | 6* (1.5) | 13** (1.2) |
Note: Entries in parentheses for nonneoplastic lesions are mean severity scores on a scale from 1 = minimal to 4 = marked.
*
Significantly different (p≤0.05) from vehicle control group by the Poly-3 test;
**
p±0.01
a
Historical incidence for 2-year gavage studies with corn oil vehicle control groups (mean ± standard deviation): 1/349 (0.3%±0.8%), range 0%-2%; all routes: 7/1,143 (0.6%±1.0%), range 0%-2%