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Study Information
Study Attribute Value
CEBS Accession Number: 002-02932-0001-0000-9
Chemical Name: Triamterene
CASRN: 396-01-0
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 695685_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 05/16/1982    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 Dimethyl Sulfoxide 
0         
 50 1039 451 0.434 9.02 26.0 0.000
Negative (Not Specified) 
0         
 50 1047 430 0.411 8.60 26.0 -5.385
Test Chemical Triamterene 
 0.5       
 50 1046 414 0.396 8.28 26.0 -8.818 
1.6       
 50 1034 520 0.503 10.40 26.0 15.857 
5         
 50 1038 503 0.485 10.06 26.0 11.637 
16         
 50 1019 738 0.724 14.76 26.0 66.848
Positive Control Mitomycin-C 
 0.005     
 50 1039 1581 1.522 31.62 26.0 250.554
Trend: 9.509        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 09/06/1982    Trial Call: 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 Dimethyl Sulfoxide 
0         
 50 1033 411 0.398 8.22 26.0 0.000
Negative (Not Specified) 
0         
 50 1044 381 0.365 7.62 26.0 -8.276
Test Chemical Triamterene 
5         
 50 1046 497 0.475 9.94 26.0 19.422 
10         
 50 1039 641 0.617 12.82 26.0 55.060 
20         
 50 1037 1017 0.981 20.34 26.0 146.491 
40         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.005     
 50 1050 1393 1.327 27.86 26.0 233.442
Mitomycin-C 
 0.01      
 50 1045 2049 1.961 40.98 26.0 392.815
Trend: 17.319        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 05/17/1982    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 1043 602 0.577 12.04 26.0 4.155
Dimethyl Sulfoxide 
0         
 50 1034 573 0.554 11.46 26.0 0.000
Test Chemical Triamterene 
5         
 50 1034 522 0.505 10.44 26.0 -8.901 
16         
 50 1017 437 0.430 8.74 26.0 -22.460 
50         
 50 1028 661 0.643 13.22 26.0 16.031 
160         
 50 1025 590 0.576 11.80 26.0 3.871 
500         
 0 0 0 0.000 0.00 26.0 N/A
Positive Control Cyclophosphamide 
2         
 50 1039 3005 2.892 60.10 26.0 421.909
Trend: 2.474        
Probability: 0.007        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 09/06/1982    Trial Call: 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 Negative (Not Specified) 
0         
 50 1048 387 0.369 7.74 26.0 -11.000
Dimethyl Sulfoxide 
0         
 50 1046 434 0.415 8.68 26.0 0.000
Test Chemical Triamterene 
5         
 50 1048 424 0.405 8.48 26.0 -2.491 
16         
 50 1051 437 0.416 8.74 26.0 0.212 
50         
 50 1044 485 0.465 9.70 26.0 11.965 
160         
 50 1047 696 0.665 13.92 26.0 60.215 
500         
 50 1036 909 0.877 18.18 26.0 111.469
Positive Control Cyclophosphamide 
1.5       
 50 1044 1894 1.814 37.88 26.0 337.242
Cyclophosphamide 
2         
 50 1049 3083 2.939 61.66 26.0 608.337
Trend: 16.472        
Probability: 0.000