Table 3.
Selected findings for F344/N rats and B6C3F1 mice in the 2-year oral gavage study of N,N-dimethyl-p-toluidine.
| Male rats (mg/kg) | 0 | 6 | 20 | 60 |
| Final survival | 38 | 40 | 33 | 25 |
| Final mean body weight (g) | 500 | 517 | 475 | 411 |
| Final mean body weight (% control) | — | 103 | 95 | 82 |
| Hematocrit (%) | 48.8 ± 0.5 | 48.4 ± 0.4 | 46.5 ± 0.3** | 42.6 ± 0.3** |
| Hemoglobin (g/dl) | 16.0 ± 0.2 | 15.6 ± 0.1* | 14.7 ± 0.1** | 13.2 ± 0.1** |
| Erythrocytes (106/μl) | 9.10 ± 0.10 | 9.02 ± 0.06 | 8.53 ± 0.04** | 7.61 ± 0.06** |
| Reticulocytes (106/μl) | 0.25 ± 0.01 | 0.26 ± 0.01* | 0.35 ± 0.01** | 0.69 ± 0.02** |
| Mean cell volume (fl) | 53.7 ± 0.2 | 53.6 ± 0.2 | 54.5 ± 0.2** | 56.0 ± 0.1** |
| Mean cell hemoglobin (pg) | 17.5 ± 0.1 | 17.3 ± 0.1 | 17.3 ± 0.1 | 17.3 ± 0.1 |
| Mean cell hemoglobin concentration (g/dl) | 32.7 ± 0.2 | 32.2 ± 0.2 | 31.6 ± 0.1** | 30.9 ± 0.2** |
| Methemoglobin (g/dl) | 0.77 ± 0.04 | 0.88 ± 0.03* | 1.14 ± 0.03** | 2.30 ± 0.03** |
| Methemoglobin (% hemoglobin) | 4.70 ± 0.26 | 5.60 ± 0.22* | 7.90 ± 0.18** | 17.40 ± 0.22** |
| Heinz bodies (% erythrocytes) | 0.0 ± 0.0 | 0.1 ± 0.1 | 0.7 ± 0.2** | 3.7 ± 0.3** |
| Female rats (mg/kg) | 0 | 6 | 20 | 60 |
| Final survival | 34 | 43 | 38 | 38 |
| Final mean body weight (g) | 353 | 368 | 346 | 291 |
| Final mean body weight (% control) | — | 104 | 98 | 82 |
| Hematocrit (%) | 46.9 ± 0.5 | 45.8 ± 0.6 | 44.2 ± 0.6** | 41.3 ± 0.6** |
| Hemoglobin (g/dl) | 15.8 ± 0.2 | 15.1 ± 0.2* | 14.4 ± 0.2** | 13.2 ± 0.1** |
| Erythrocytes (106/μl) | 8.50 ± 0.09 | 8.31 ± 0.10 | 7.88 ± 0.08** | 6.95 ± 0.09** |
| Reticulocytes (106/μl) | 0.24 ± 0.01 | 0.24 ± 0.01 | 0.35 ± 0.01** | 0.70 ± 0.02** |
| Mean cell volume (fl) | 55.1 ± 0.2 | 55.1 ± 0.2 | 56.1 ± 0.3* | 59.4 ± 0.2** |
| Mean cell hemoglobin (pg) | 18.6 ± 0.1 | 18.2 ± 0.1* | 18.3 ± 0.1 | 19.0 ± 0.1 |
| Mean cell hemoglobin concentration (g/dl) | 33.8 ± 0.2 | 33.1 ± 0.2* | 32.6 ± 0.2** | 32.0 ± 0.2** |
| Methemoglobin (g/dl) | 0.80 ± 0.03 | 0.87 ± 0.03 | 1.21 ± 0.05** | 2.26 ± 0.07** |
| Methemoglobin (% hemoglobin) | 5.10 ± 0.23 | 5.60 ± 0.27 | 8.40 ± 0.31** | 17.10 ± 0.41** |
| Heinz bodies (% erythrocytes) | 0.0 ± 0.0 | 0.3 ± 0.2* | 0.9 ± 0.3** | 3.8 ± 0.2** |
| Male mice (mg/kg) | 0 | 15 | 30 | 60 |
| Final survival | 36 | 39 | 33 | 36 |
| Final mean body weight (g) | 55.3 | 53.3 | 50.4 | 46.5 |
| Final mean body weight (% control) | — | 97 | 91 | 84 |
| Female mice (mg/kg) | 0 | 15 | 30 | 60 |
| Final survival | 43 | 43 | 42 | 34 |
| Final mean body weight (g) | 62.8 | 61.0 | 63.9 | 45.0 |
| Final mean body weight (% control) | — | 101 | 104 | 84 |
Note. N = 10 for male and female rat hematology end points at 3 months into the 2-year studies (hematology end points for rats at 3 months; hematology end points not taken for mice).