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Study Information
Study Attribute Value
CEBS Accession Number: 002-01547-0001-0000-0
Chemical Name: 5-Nitro-o-toluidine
CASRN: 99-55-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 012878_SCE
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1  Questionable 
Induced Rat Liver S9  1_S9  Positive 
Induced Rat Liver S9  2_S9  Weakly Positive 

Trial #: 1    Activation: No Activation    Date: 02/17/1987    Trial Call: Questionable   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1049 420 0.400 8.40 26.0 0.000
Test Chemical 5-Nitro-o-toluidine 
1.6       
 50 1050 355 0.338 7.10 26.0 -15.557 
5         
 50 1049 381 0.363 7.62 26.0 -9.286 
16         
 50 1050 454 0.432 9.08 26.0 7.992 
50         
 50 1049 455 0.434 9.10 26.0 8.333
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 602 0.574 12.04 26.0 43.333
Mitomycin-C 
 0.005     
 10 210 301 1.433 30.10 26.0 257.992
Trend: 2.636        
Probability: 0.004        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 02/17/1987    Trial Call: Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1050 378 0.360 7.56 26.0 0.000
Test Chemical 5-Nitro-o-toluidine 
50         
 50 1048 440 0.420 8.80 26.0 16.624 
160         
 50 1051 481 0.458 9.62 26.0 27.128 
500         
 50 1051 470 0.447 9.40 26.0 24.220 
1600         
 0 0 0 0.000 0.00 26.0 N/A 
5000         
 50 1049 468 0.446 9.36 26.0 23.928
Positive Control Cyclophosphamide 
 0.1       
 50 1051 531 0.505 10.62 26.0 40.343
Cyclophosphamide 
 0.6       
 10 212 216 1.019 21.60 26.0 183.019
Trend: 2.838        
Probability: 0.002        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 06/10/1987    Trial Call: Weakly Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1049 453 0.432 9.06 26.0 0.000
Test Chemical 5-Nitro-o-toluidine 
50         
 50 1050 452 0.430 9.04 26.0 -0.316 
160         
 50 1051 467 0.444 9.34 26.0 2.894 
500         
 50 1050 514 0.490 10.28 26.0 13.358 
1600         
 0 0 0 0.000 0.00 31.0 N/A 
5000         
 50 1049 678 0.646 13.56 31.0 49.669
Positive Control Cyclophosphamide 
 0.1       
 50 1047 570 0.544 11.40 26.0 26.068
Cyclophosphamide 
 0.6       
 10 210 219 1.043 21.90 26.0 141.492
Trend: 7.776        
Probability: 0.000