U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Study Information
Study Attribute Value
CEBS Accession Number: 002-02759-0002-0000-7
Chemical Name: Pyrimethamine
CASRN: 58-14-0
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 074874_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 01/26/1983    Harvest Time: 14 hour(s)   Trial Call: Negative   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 3 0.030 3.0 1 0.010 1.0 2 0.020 2.0 0 0.000 0.0
Test Chemical: Pyrimethamine 
20         
 100 5 0.050 5.0 0 0.000 0.0 5 0.050 5.0 0 0.000 0.0 
64         
 100 7 0.070 7.0 1 0.010 1.0 6 0.060 6.0 0 0.000 0.0 
200         
 100 9 0.090 9.0 2 0.020 2.0 7 0.070 7.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.15      
 50 20 0.400 26.0 7 0.140 10.0 13 0.260 18.0 0 0.000 0.0
Trend: 1.883 0.898 1.642  
Probability: 0.030 0.185 0.050  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 01/26/1982    Harvest Time: 14 hour(s)   Trial Call: Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Pyrimethamine 
20         
 100 7 0.070 6.0 1 0.010 1.0 6 0.060 5.0 0 0.000 0.0 
64         
 100 9 0.090 8.0 1 0.010 1.0 8 0.080 7.0 0 0.000 0.0 
200         
 100 9 0.090 9.0 0 0.000 0.0 9 0.090 9.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
15         
 50 10 0.200 20.0 3 0.060 6.0 7 0.140 14.0 0 0.000 0.0
Trend: 2.449 0.003 2.551  
Probability: 0.007 0.499 0.005