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Study Information
Study Attribute Value
CEBS Accession Number: 002-02237-0001-0000-7
Chemical Name: Heptachlor
CASRN: 76-44-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 234168_SCE
Study Result: Weakly Positive

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

Trial #: 1    Activation: No Activation    Date: 07/31/1990    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 Acetone 
0         
 50 1047 421 0.402 8.42 26.0 0.000
Negative (Not Specified) 
0         
 50 1045 378 0.362 7.56 26.0 -10.042
Test Chemical Heptachlor 
 0.5       
 50 1050 441 0.420 8.82 26.0 4.451 
1.7       
 50 1048 454 0.433 9.08 26.0 7.736 
5         
 50 1038 457 0.440 9.14 26.0 9.492 
17         
 0 0 0 0.000 0.00 31.0 N/A 
50         
 0 0 0 0.000 0.00 0.0 N/A 
5000         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1049 534 0.509 10.68 26.0 26.599
Mitomycin-C 
 0.004     
 10 210 275 1.310 27.50 26.0 225.670
Trend: 1.438        
Probability: 0.075        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 07/31/1990    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 Acetone 
0         
 50 1049 395 0.377 7.90 31.0 -0.253
Acetone 
0         
 50 1049 396 0.378 7.92 26.0 0.000
Test Chemical Heptachlor 
5         
 50 1050 416 0.396 8.32 26.0 4.950 
17         
 50 1040 427 0.411 8.54 26.0 8.761 
50         
 50 1043 484 0.464 9.68 31.0 22.925 
167         
 0 0 0 0.000 0.00 0.0 N/A 
5000         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Cyclophosphamide 
 0.125     
 50 1048 613 0.585 12.26 26.0 54.946
Cyclophosphamide 
 0.5       
 10 210 196 0.933 19.60 26.0 147.239
Trend: 2.986        
Probability: 0.001        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 11/08/1990    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 Acetone 
0         
 50 1050 397 0.378 7.94 26.0 0.000
Acetone 
0         
 50 1048 385 0.367 7.70 31.0 -2.838
Test Chemical Heptachlor 
20         
 50 1049 430 0.410 8.60 26.0 8.416 
35         
 50 1048 455 0.434 9.10 26.0 14.828 
50         
 50 1047 500 0.478 10.00 31.0 26.305 
75         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Cyclophosphamide 
 0.125     
 50 1050 569 0.542 11.38 26.0 43.325
Cyclophosphamide 
 0.5       
 10 209 262 1.254 26.20 26.0 231.554
Trend: 3.540        
Probability: 0.000