Table 1.
Incidences of neoplasms and nonneoplastic lesions of the kidney in F/344N rats exposed to benzophenone in feed for 2 years
| 0 ppm | 312 ppm | 625 ppm | 1,250 ppm | |
|---|---|---|---|---|
| Males | ||||
|
| ||||
| Number Examined | 50 | 50 | 50 | 50 |
| Single Sections (Standard Evaluation) | ||||
| Renal Tubule, Hyperplasiaa | 1 (1.0)b | 5 (1.4) | 20** (1.5) | 23** (1.3) |
| Nephropathy | 50 (1.3) | 45 (2.4)▲ | 50 (3.3) ▲ | 50 (3.8) ▲ |
| Renal Tubule, Adenoma | 1 | 1 | 2 | 4 |
| Renal Tubule, Carcinoma | 0 | 1 | 0 | 0 |
| Renal Tubule, Cyst | 0 | 0 | 1 | 9** |
| Step Sections | ||||
| Renal Tubule Hyperplasia | 2 (1.0) | 8* (1.1) | 26** (2.0) | 37** (2.2) |
| Renal Tubule, Adenoma | 1 | 1 | 5 | 4 |
| Renal Tubule, Carcinoma | 0 | 1 | 0 | 0 |
| Single and Step Sections (Combined) | ||||
| Renal Tubule, Hyperplasia | 3 (1.0) | 11* (1.3) | 30** (1.8) | 40** (2.1) ▲ |
| Renal Tubule, Adenoma | 2 | 2 | 7 | 8* |
| Renal Tubule, Carcinoma | 0 | 1 | 0 | 0 |
|
| ||||
| Females | ||||
|
| ||||
| Number Examined | 50 | 50 | 50 | 50 |
| Single Sections (Standard Evaluation) | ||||
| Renal Tubule, Hyperplasia | 0 | 1 (4.0) | 1 (3.0) | 1 (4.0) |
| Nephropathy | 47 (1.1) | 49 (1.4) | 48 (1.7) ▲ | 49 (2.0) ▲ |
| Renal Tubule, Adenoma, Multiple | 0 | 0 | 2 | 1 |
| Step Sections | ||||
| Renal Tubule Hyperplasia | 1 (1.0) | 7* (1.1) | 9* (2.1) | 6 (1.7) |
| Renal Tubule, Adenoma | 3 | 0 | 2 | 1 |
| Single and Step Sections (Combined) | ||||
| Renal Tubule, Hyperplasia | 1 (1.0) | 8* (1.5) | 10** (2.2) | 7* (2.0) |
| Renal Tubule, Adenoma, Multiple | 0 | 0 | 1 | 1 |
| Renal Tubule, Adenoma (includes multiple) | 3 | 0 | 2 | 1 |
*
Significantly different (p ≤ 0.05) from the control group by the Poly-3 test
**
p ≤ 0.01
▲
Severity significantly different (p ≤ 0.05) from the control group by the Mann-Whitney U test
a
Number of animals with lesions
b
Average severity grade of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked