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Study Information
Study Attribute Value
CEBS Accession Number: 002-02504-0001-0000-4
Chemical Name: N,N'-Diethylthiourea
CASRN: 105-55-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 481340_SCE
Study Result: Negative

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

Trial #: 1    Activation: No Activation    Date: 03/23/1983    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 1049 428 0.408 8.56 26.0 0.000
Test Chemical N,N'-Diethylthiourea 
50         
 50 1046 380 0.363 7.60 26.0 -10.960 
160         
 50 1045 362 0.346 7.24 26.0 -15.097 
500         
 50 1046 406 0.388 8.12 26.0 -4.868
Positive Control Mitomycin-C 
 0.005     
 50 1048 687 0.656 13.74 26.0 60.667
Trend: -0.910        
Probability: 0.819        

Trial #: 2    Activation: No Activation    Date: 05/05/1983    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 1049 399 0.380 7.98 26.0 0.000
Test Chemical N,N'-Diethylthiourea 
500         
 50 1049 469 0.447 9.38 26.0 17.544 
600         
 100 2097 939 0.448 9.39 26.0 17.725 
700         
 50 1046 470 0.449 9.40 26.0 18.132
Positive Control Mitomycin-C 
 0.005     
 25 524 735 1.403 29.40 26.0 268.773
Trend: 2.395        
Probability: 0.008        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 03/23/1983    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 1046 448 0.428 8.96 26.0 0.000
Test Chemical N,N'-Diethylthiourea 
500         
 50 1048 455 0.434 9.10 26.0 1.369 
1600         
 50 1047 440 0.420 8.80 26.0 -1.880 
5000         
 50 1050 587 0.559 11.74 26.0 30.528
Positive Control Cyclophosphamide 
1         
 50 1049 912 0.869 18.24 26.0 102.989
Trend: 4.027        
Probability: 0.000        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 05/18/1983    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 1049 473 0.451 9.46 26.0 0.000
Test Chemical N,N'-Diethylthiourea 
3000         
 50 1048 503 0.480 10.06 26.0 6.444 
4000         
 50 1044 500 0.479 10.00 26.0 6.215 
5000         
 50 1048 548 0.523 10.96 26.0 15.967
Positive Control Cyclophosphamide 
1         
 50 1046 895 0.856 17.90 26.0 89.760
Trend: 2.198        
Probability: 0.014