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Study Information
Study Attribute Value
CEBS Accession Number: 002-02756-0003-0000-5
Chemical Name: Pyridine
CASRN: 110-86-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 631306_SCE
Study Result: Not a Valid Test

Study Result: Not a Valid Test
Activation Trial Trial Call
No Activation  1  Test Failure 
No Activation  2  Test Failure 
Induced Rat Liver S9  1_S9  Test Failure 
Induced Rat Liver S9  2_S9  Test Failure 
Induced Rat Liver S9  3_S9  Test Failure 

Trial #: 1    Activation: No Activation    Date: 08/11/1983    Trial Call: Test Failure   
  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 Medium 
0         
 50 1048 503 0.480 10.06 25.8 0.000
Test Chemical Pyridine 
977         
 50 1039 506 0.487 10.12 25.8 1.468 
3260         
 0 0 0 0.000 0.00 25.8 N/A
Positive Control Mitomycin-C 
 0.0015    
 50 1051 683 0.650 13.66 25.8 35.398
Mitomycin-C 
 0.01      
 5 104 177 1.702 35.40 25.8 254.596
Trend: 0.231        
Probability: 0.408        

Trial #: 2    Activation: No Activation    Date: 08/25/1983    Trial Call: Test Failure   
  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 Medium 
0         
 50 1044 474 0.454 9.48 25.8 0.000
Test Chemical Pyridine 
2740         
 50 1043 600 0.575 12.00 35.8 26.704 
3000         
 50 1033 574 0.556 11.48 35.8 22.387 
3260         
 50 1043 672 0.644 13.44 35.8 41.908
Positive Control Mitomycin-C 
 0.0015    
 50 1038 710 0.684 14.20 25.8 50.655
Mitomycin-C 
 0.01      
 5 105 183 1.743 36.60 25.8 283.870
Trend: 5.310        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 08/11/1983    Trial Call: Test Failure   
  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 Medium 
0         
 50 1043 554 0.531 11.08 25.8 0.000
Test Chemical Pyridine 
3260         
 50 1043 523 0.501 10.46 25.8 -5.596 
9770         
 0 0 0 0.000 0.00 25.8 N/A
Positive Control Cyclophosphamide 
 0.4       
 50 1047 683 0.652 13.66 25.8 22.814
Cyclophosphamide 
2         
 5 104 201 1.933 40.20 25.8 263.862
Trend: -0.945        
Probability: 0.828        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 08/25/1983    Trial Call: Test Failure   
  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 Medium 
0         
 50 1045 489 0.468 9.78 25.8 0.000
Test Chemical Pyridine 
5710         
 50 1048 597 0.570 11.94 25.8 21.736 
6520         
 50 1038 579 0.558 11.58 25.8 19.203 
7340         
 50 1045 576 0.551 11.52 25.8 17.791 
8150         
 0 0 0 0.000 0.00 35.8 N/A
Positive Control Cyclophosphamide 
 0.4       
 50 1047 747 0.713 14.94 25.8 52.469
Cyclophosphamide 
2         
 5 102 205 2.010 41.00 25.8 329.498
Trend: 2.319        
Probability: 0.010        

Trial #: 3_S9    Activation: Induced Rat Liver S9    Date: 10/04/1983    Trial Call: Test Failure   
  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 Medium 
0         
 50 1044 514 0.492 10.28 25.5 0.000
Test Chemical Pyridine 
7500         
 50 1041 555 0.533 11.10 30.5 8.288 
7820         
 50 1039 585 0.563 11.70 30.5 14.361 
8150         
 50 1045 623 0.596 12.46 30.5 21.090
Positive Control Cyclophosphamide 
 0.4       
 50 1043 696 0.667 13.92 25.5 35.538
Cyclophosphamide 
2         
 5 106 188 1.774 37.60 25.5 260.238
Trend: 3.338        
Probability: 0.000