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Study Information
Study Attribute Value
CEBS Accession Number: 002-02308-0002-0000-7
Chemical Name: Isobutyl nitrite
CASRN: 542-56-3
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 016060_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 04/04/1990    Harvest Time: 15 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: Negative (Not Specified)
0         
200 4 0.020 1.5 2 0.010 1.0 2 0.010 0.5 0 0.000 0.0
Dimethyl Sulfoxide
0         
200 3 0.015 1.5 2 0.010 1.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Isobutyl nitrite
24         
200 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
51         
200 22 0.110 8.0 2 0.010 1.0 20 0.100 7.0 0 0.000 0.0
109         
100 61 0.610 28.0 2 0.020 2.0 49 0.490 25.0 10 0.100 1.0
234         
0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C
 0.4       
25 12 0.480 36.0 4 0.160 16.0 8 0.320 24.0 0 0.000 0.0
Trend: 8.147 0.909 8.152  
Probability: 0.000 0.182 0.000  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 04/04/1990    Harvest Time: 15.7 hour(s)   Trial Call: Weakly 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: Negative (Not Specified)
0         
200 3 0.015 1.5 1 0.005 0.5 2 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide
0         
200 10 0.050 4.0 2 0.010 1.0 8 0.040 3.5 0 0.000 0.0
Test Chemical: Isobutyl nitrite
234         
200 12 0.060 5.0 7 0.035 3.0 5 0.025 2.0 0 0.000 0.0
503         
200 5 0.025 2.5 1 0.005 0.5 4 0.020 2.0 0 0.000 0.0
1081         
200 32 0.160 13.0 6 0.030 3.0 26 0.130 11.0 0 0.000 0.0
2325         
0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide
20         
25 13 0.520 40.0 12 0.480 36.0 1 0.040 4.0 0 0.000 0.0
Trend: 3.231 0.816 3.387  
Probability: 0.001 0.207 0.000  


Trial #:2   Activation: No Activation    Date: 06/26/1990    Harvest Time: 15 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         
200 2 0.010 1.0 0 0.000 0.0 2 0.010 1.0 0 0.000 0.0
Negative (Not Specified)
0         
200 3 0.015 1.5 2 0.010 1.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Isobutyl nitrite
100         
200 8 0.040 4.0 4 0.020 2.0 4 0.020 2.0 0 0.000 0.0
150         
200 11 0.055 5.5 5 0.025 2.5 6 0.030 3.0 0 0.000 0.0
200         
100 52 0.520 26.0 6 0.060 6.0 35 0.350 22.0 11 0.110 2.0
Positive Control: Mitomycin-C
 0.4       
25 24 0.960 44.0 7 0.280 24.0 7 0.280 28.0 10 0.400 4.0
Trend: 6.681 3.143 6.210  
Probability: 0.000 0.001 0.000