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Study Information
Study Attribute Value
CEBS Accession Number: 002-02318-0009-0000-5
Chemical Name: Isophorone
CASRN: 78-59-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 490210
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         
 76 94 84 37 43
    71 97 112 53
    139r 97 128 31
    94 108 107 38
Test Chemical Isophorone 
50         
 74 156 83 38 36
    73 147 73 33
  
100         
 82 228 99 40 33
    87 161 69 26
  
200         
 92 160 161 58 54
    95 150 141 49
  
400         
 50 75 114 76 70*
    81 126 153 63
  
800         
 66 31 244 124 147*
    74 28 378 170
  
1600         
   
Positive Control Methyl Methane Sulfonate 
15         
 38 23 413 362 347*
    47 17 469 333

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         
 40r 101 65 54 51
    50 100 80 53
    46r 97 74 53
    53 100 79 50
Test Chemical Isophorone 
400         
 56 112 79 47 55
    74 118 139 62
  
600         
 73 92 161 74 75
    77 74 175 76
  
800         
 58 50 152 87 90*
    68 62 188 92
  
1000         
 61 27 307 167 157*
    74 19 328 147
  
1200         
 60 14 322 180 227*
    42 7 344 274
Positive Control Methyl Methane Sulfonate 
15         
 12 13 69 189 235*
    15 22 128 281

Nonactivation Trial: 3 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 76 104 145 64 79
    63 86 167 89
    89 103 224 84
    71 107 166 78
Test Chemical Isophorone 
200         
 62 59 141 76 83
    71 96 195 91
  
400         
 51 52 188 122 106
    65 66 175 90
  
600         
 57 36 201 118 118
    57 35 204 119
  
800         
 63 26 310 165 166*
    45 22 225 167
  
1000         
 29 5 402 454 336*
    33 7 214 218
Positive Control Methyl Methane Sulfonate 
15         
 28 21 403 477 649*
    19 15 476 821

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