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Study Information
Study Attribute Value
CEBS Accession Number: 002-01250-0004-0000-4
Chemical Name: 2,6-Diisocyanatotoluene
CASRN: 91-08-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 429581
Study Result: Positive


Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 73 115 61 28 29
    65 81 42 22
    67 117 48 24
    53 86 69 43
Test Chemical 2,6-Diisocyanatotoluene 
15.5625    
 76 96 74 33 27
    66 79 43 22
  
31.125     
 56 67 52 31 35
    61 67 71 39
  
62.5       
 69 61 86 41 50*
    71 50 127 59
  
125         
 55 24 127 77 77*
    53 19 123 78
  
250         
 34 5 227 224 177*
    61 10 238 130
  
500         
   
Positive Control Methyl Methane Sulfonate 
15         
 27 18 120 150 146*
    20 16 85 142

Nonactivation Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 73 104 83 38 32
    63 103 61 33
    77 86 65 28
    75 107 63 28
Test Chemical 2,6-Diisocyanatotoluene 
25         
 80 66 118 49 46
    77 57 97 42
  
50         
 69 42 131 63 60*
    66 47 113 57
  
100         
 60 12 237 131 112*
    61 9 170 93
  
150         
   
Positive Control Methyl Methane Sulfonate 
15         
 32 18 154 162 166*
    32 23 164 171

Induced S9 Trial: 1 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 74 99 74 33 38
    69 84 92 44
    71 113 71 33
    74 104 88 40
Test Chemical 2,6-Diisocyanatotoluene 
25         
 76 74 119 53 42
    73 92 70 32
  
50         
 73 44 138 63 54
    68 50 90 44
  
100         
 75 52 142 63 75*
    66 37 171 87
  
150         
 56 28 154 91 90*
    59 27 157 89
  
200         
 57 11 142 84 96*
    51 15 163 107
  
250         
   
Positive Control 3-Methylcholanthrene 
2.5       
 54 30 388 240 284*
    35 20 344 328

Induced S9 Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 75 101 111 50 56
    49r 85 124 84
    57 96 91 53
    69 103 137 66
Test Chemical 2,6-Diisocyanatotoluene 
10         
 57 99 106 62 66
    40 50 83 69
  
25         
 33 43 116 118 95*
    53 66 114 72
  
50         
 38 30 140 123 132*
    40 34 169 141
  
100         
 29 8 222 251 229*
    34 9 213 207
  
150         
 34 6 258 250 227*
    36 10 219 203
  
200         
   
Positive Control 3-Methylcholanthrene 
2.5       
 39 29 674 571 521*
    41 30 583 470

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination