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Study Information
Study Attribute Value
CEBS Accession Number: 002-02114-0001-0000-1
Chemical Name: Endrin
CASRN: 72-20-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 177824_SCE
Study Result: Negative

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

Trial #: 1    Activation: No Activation    Date: 10/02/1984    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 Dimethyl Sulfoxide 
0         
 50 1051 484 0.461 9.68 26.0 0.000
Negative (Not Specified) 
0         
 50 1050 382 0.364 7.64 26.0 -20.999
Test Chemical Endrin 
50         
 50 1050 495 0.471 9.90 26.0 2.370 
160         
 50 1049 472 0.450 9.44 26.0 -2.293 
500         
 50 1048 505 0.482 10.10 26.0 4.638 
1600         
 50 1049 481 0.459 9.62 26.0 -0.430
Positive Control Mitomycin-C 
 0.0E-4    
 50 1048 565 0.539 11.30 26.0 17.070
Mitomycin-C 
 0.005     
 50 1053 2108 2.002 42.16 26.0 334.710
Trend: 0.094        
Probability: 0.463        

Trial #: 2    Activation: No Activation    Date: 11/13/1984    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 1032 411 0.398 8.22 26.5 0.000
Test Chemical Endrin 
100         
 15 314 127 0.404 8.47 26.5 1.557 
250         
 50 1045 424 0.406 8.48 33.0 1.880 
500         
 50 1044 494 0.473 9.88 33.0 18.813 
1000         
 50 1053 501 0.476 10.02 33.0 19.467 
1600         
 0 0 0 0.000 0.00 33.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1048 647 0.617 12.94 26.5 55.018
Mitomycin-C 
 0.005     
 10 210 279 1.329 27.90 26.5 233.597
Trend: 3.215        
Probability: 0.001        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 10/08/1984    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 1050 412 0.392 8.24 26.5 0.000
Test Chemical Endrin 
50         
 50 1047 417 0.398 8.34 26.5 1.504 
160         
 50 1047 428 0.409 8.56 26.5 4.181 
500         
 50 1047 428 0.409 8.56 26.5 4.181 
1600         
 50 1043 418 0.401 8.36 26.5 2.137
Positive Control Cyclophosphamide 
 0.3       
 50 1043 583 0.559 11.66 26.5 42.455
Cyclophosphamide 
 0.6       
 10 209 194 0.928 19.40 26.5 136.563
Trend: 0.442        
Probability: 0.329        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 11/13/1984    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 1045 421 0.403 8.42 26.0 0.000
Test Chemical Endrin 
250         
 50 1044 459 0.440 9.18 26.0 9.131 
500         
 50 1040 480 0.462 9.60 26.0 14.562 
1000         
 50 1047 464 0.443 9.28 26.0 10.003 
1600         
 50 1049 461 0.439 9.22 26.0 9.084
Positive Control Cyclophosphamide 
 0.3       
 50 1046 770 0.736 15.40 26.0 82.723
Cyclophosphamide 
 0.6       
 10 209 187 0.895 18.70 26.0 122.090
Trend: 1.220        
Probability: 0.111