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Study Information
Study Attribute Value
CEBS Accession Number: 002-01677-0001-0000-4
Chemical Name: Azobenzene
CASRN: 103-33-3
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 657475_SCE
Study Result: Negative

Study Result: Negative
Activation Trial Trial Call
No Activation  1   
No Activation  2  Negative 
Induced Rat Liver S9  1_S9  Negative 

Trial #: 1    Activation: No Activation    Date: 09/12/1980    Trial Call:   
  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 1048 387 0.369 7.74 26.5 0.000
Negative (Not Specified) 
0         
 50 1049 373 0.356 7.46 26.5 -3.709
Test Chemical Azobenzene 
 0.016     
 50 1049 359 0.342 7.18 26.5 -7.324 
 0.08      
 50 1048 360 0.344 7.20 26.5 -6.977 
 0.4       
 50 1047 346 0.330 6.92 26.5 -10.509 
2         
 50 1046 365 0.349 7.30 26.5 -5.504 
10         
 50 1048 395 0.377 7.90 26.5 2.067 
50         
 0 0 0 0.000 0.00 28.5 N/A
Positive Control Triethylenemelamine 
 0.015     
 50 1050 1806 1.720 36.12 26.5 365.778
Trend: 0.296        
Probability: 0.384        

Trial #: 2    Activation: No Activation    Date: 11/20/1980    Trial Call: Negative   
  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 Negative (Not Specified) 
0         
 50 1015 406 0.400 8.12 26.5 -5.421
Dimethyl Sulfoxide 
0         
 50 1012 428 0.423 8.56 26.5 0.000
Test Chemical Azobenzene 
15         
 50 1048 420 0.401 8.40 26.5 -5.240 
20         
 50 1044 399 0.382 7.98 26.5 -9.633 
25         
 50 1042 384 0.369 7.68 26.5 -12.863 
30         
 50 1043 464 0.445 9.28 31.5 5.189 
35         
 50 1045 428 0.410 8.56 31.5 -3.158
Positive Control Triethylenemelamine 
 0.015     
 50 1030 2436 2.365 48.72 26.5 459.212
Trend: 0.182        
Probability: 0.428        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 09/12/1980    Trial Call: Negative   
  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 1042 359 0.345 7.18 26.5 0.000
Negative (Not Specified) 
0         
 50 1037 328 0.316 6.56 26.5 -8.195
Test Chemical Azobenzene 
 0.001     
 50 1045 358 0.343 7.16 26.5 -0.565 
 0.015     
 50 1048 344 0.328 6.88 26.5 -4.727 
 0.15      
 50 1043 360 0.345 7.20 26.5 0.182 
1.15      
 50 1044 381 0.365 7.62 26.5 5.925 
15         
 50 59 46 0.780 0.92 26.5 126.297
Positive Control Cyclophosphamide 
1.5       
 50 1047 1900 1.815 38.00 26.5 426.720
Trend: 1.806        
Probability: 0.035