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Study Information
Study Attribute Value
CEBS Accession Number: 002-01538-0008-0000-7
Chemical Name: 5-Chloro-o-toluidine
CASRN: 95-79-4
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 250705
Study Result: Negative


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: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 62 91 66 36 35
    75# 92 81 36
    80 90 97 40
    93 127 80 29
Test Chemical 5-Chloro-o-toluidine 
60         
 51 79 69 45 51
    66 90 111 56
  
120         
 68 71 67 33 34
    78 86 85 36
  
180         
 104 63 98 31 25
    77# 61 42 18
  
240         
 110 40 69 21 23
    92 41 69 25
  
300         
 94 18 77 27 26
    89 21 67 25
  
360         
   
Positive Control Methyl Methane Sulfonate 
15         
 36# 26 126 116 106*
    29 25 84 96

Nonactivation Trial: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 91 115 126 46 62
    95 105 164 58
    52 58 147 94
    107 122 162 50
Test Chemical 5-Chloro-o-toluidine 
125         
 96 68 161 56 55
    97 77 156 54
  
175         
 114 44 185 54 56
    108 48 188 58
  
225         
 86 38 195 76 74
    82 51 179 73
  
275         
 105 20 230 73 78
    100 18 250 83
  
325         
 44 8 181 137 125*
    81 6 274 113
Positive Control Methyl Methane Sulfonate 
15         
 53# 37 424 265 276*
    52 31 443 286

Nonactivation Trial: 3 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 77 99 149 65 58
    74 101 138 63
    77 113 105 45
    73 87 133 60
Test Chemical 5-Chloro-o-toluidine 
150         
 64 50 162 84 69
    70 57 112 54
  
200         
 47 33 117 83 87
    61 32 165 90
  
250         
 64 34 147 77 74
    62 24 135 72
  
300         
 82 33 151 62 65
    73 24 149 68
  
350         
 73 16 163 74 81
    62 17 163 88
Positive Control Methyl Methane Sulfonate 
15         
 33 23 284 285 265*
    29 27 214 245

Nonactivation Trial: 4 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 72 92 63 29 29
    76 97 46 20
    77 101 72 31
    76 110 84 37
Test Chemical 5-Chloro-o-toluidine 
175         
 74 46 77 35 42
    62 58 91 49
  
225         
 68 53 71 35 41
    71 55 100 47
  
275         
 75 55 91 41 44
    70 50 98 47
  
325         
 73 40 74 34 33
    59 48 57 32
  
375         
 67 26 54 27 38
    58 39 87 50
Positive Control Methyl Methane Sulfonate 
15         
 42 33 168 133 136*
    38 34 159 138

Induced S9 Trial: 1 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 69 108 119 58 67
    58 103 118 68
    72 93 137 64
    64 96 148 77
Test Chemical 5-Chloro-o-toluidine 
175         
 80 72 182 76 83
    68 61 184 91
  
225         
 74 62 161 73 77
    82 67 201 82
  
275         
 81 56 203 84 84
    71 51 179 84
  
325         
 71 37 150 70 91
    57 29 193 113
  
375         
 66 33 207 105 99
    69 34 192 93
Positive Control 3-Methylcholanthrene 
2.5       
 58# 51 565.5 328 331*
    57 54 572 334

Induced S9 Trial: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 56 87 34 20 25
    59 90 50 28
    71 108 55 26
    65 116 53 27
Test Chemical 5-Chloro-o-toluidine 
175         
 58 65 54 31 33
    61 60 65 35
  
225         
 69 66 52 25 29
    59 54 59 33
  
275         
 59 52 64 36 28
    63 56 37 20
  
325         
 39 17 42 36 29
    71 28 46 22
  
375         
 60 13 70 39 29
    52 12 30 19
  
425         
   
Positive Control 3-Methylcholanthrene 
2.5       
 44 39 380 291 288*
    35 35 299 285

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