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Study Information
Study Attribute Value
CEBS Accession Number: 002-02042-0033-0000-6
Chemical Name: Diethylstilbestrol
CASRN: 56-53-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: G19656
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: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 87 149 39 15 17
    69 103 40 19
Test Chemical Diethylstilbestrol 
12.5       
 75 23 28 13 14
    108 25 51 16
  
25         
 68 25 34 17 16
    78 25 36 15
  
50         
 54 19 27 17 19
    69 24 46 22
  
75         
    64 21 29 15
  
125         
   
Positive Control Ethyl Methane Sulfonate 
500         
 40 20 652 543 716*
    19 11 506 888
Negative Control Negative (Not Specified) 
 0         
 78 53 33 14 17*
    73 94 43 20

Nonactivation Trial: 3 Experiment Call: No Call
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 88 91 58 22 23
    83 158 61 24
Test Chemical Diethylstilbestrol 
25         
 55 28 76 46 45*
    69 22 90 44
  
60         
 55 21 54 33 31
    55# 18 49.5 30
  
70         
 68 32 86 42 38
    58 18 59 34
  
80         
 92 50 81 29 27
    67# 34 48 24
  
90         
 65 31 66 34 49*
    50 11 95 63
Positive Control Ethyl Methane Sulfonate 
500         
 37 23 783 699 780*
    31 11 810 862
Negative Control Negative (Not Specified) 
 0         
 86 79 63 24 21*
    85 72 44 17

Nonactivation Trial: 4 Experiment Call: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 75 81 63 28 22
    73 91 49 22
    99 131 45 15
    69 97 47 23
Test Chemical Diethylstilbestrol 
6.25      
 81 80 52 21 20
    81 86 45 19
  
12.5       
 83 89 71 28 27
    88 77 68 26
  
25         
 83 61 51 20 23
    78 85 59 25
  
50         
 71 53 57 27 27
    63# 55 51 27
  
75         
 80 36 71 29 28
    86 52 68 26
  
100         
 79 32 88 37 35
    84 41 80 32
Positive Control Ethyl Methane Sulfonate 
500         
 56 33 898 531 545*
    42 34 707 559

Nonactivation Trial: 6 Experiment Call: Inconclusive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 54 106 30 19 18
    61 89 26 14
    88 114 60 23
    68 91 30 15
Test Chemical Diethylstilbestrol 
 0.625     
 75 69 54 24 24
    69 77 45 22
    74 72 59 27
  
1.25      
 67 63 52 26 28*
    67 62 61 30
    64 58 54 28
  
2.5       
 77 75 53 23 24
    75 68 57 25
    68 60 47 23
  
5         
 88 50 40 15 22
    80 42 57 24
    67 37 51 26
  
10         
 85 44 51 20 23
    70 37 56 27
    70r 49 0 0
  
20         
 94 45 54 19 21
    60 55 36 20
    80 58 56 23
Positive Control Ethyl Methane Sulfonate 
500         
 42 34 694 555 657*
    37 20 789 717
    44 20 928 698

Nonactivation Trial: 7 Experiment Call: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 95# 91 62 22 23
    94 91 73 26
    117 118 72 21
    121r 121 90 25
Test Chemical Diethylstilbestrol 
5         
 87 81 63 24 24
    86 83 82 32
    109 79 57 17
  
10         
 83 69 66 27 31
    102 73 96 31
    97 77 99 34
  
20         
 107 67 87 27 24
    94 68 60 21
    123r 86 116 32
  
30         
 114 65 112 33 34
    99 62 101 34
    119 66 121 34
  
40         
 117 63 109 31 29
    113# 72 88 26
    121r 62 112 31
  
60         
 95 48 62 22 24
    119 25 92 26
    148r 24 134 30
Positive Control Ethyl Methane Sulfonate 
250         
 62 43 831 449 469*
    52 37 840 537
    58 47 736 422

Non-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         
 76 75 303 134 112
    97 107 260 90
Test Chemical Diethylstilbestrol 
1.9       
 83 89 288 115 117
    72 58 256 118
  
3.8       
 75# 40 239 106 120
    78 36 315 134
  
7.5       
 76 25 343 150 169
    59 18 331 188
  
15         
 58 16 326 189 197*
    78 18 479 205
  
30         
 65 24 370 190 184*
    88 24 469 177
  
40         
   
Positive Control 3-Methylcholanthrene 
7         
 65# 29 610 315 358*
    52 32 630 401
Negative Control Negative (Not Specified) 
 0         
 97 114 202 69 88*
    79 103 256 108

Non-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         
 82 112 124 50 54
    80 95 137 57
Test Chemical Diethylstilbestrol 
10         
 85 15 329 129 116*
    98 15 304 103
  
20         
 85# 14 306 120 108*
    93 18 267 95
  
30         
 89 18 266 100 94*
    86 24 229 88
  
40         
 70 6 115 55 53
    90 14 139 51
Positive Control 3-Methylcholanthrene 
7         
 85 53 397 155 195*
    77 50 539 234
Negative Control Negative (Not Specified) 
 0         
 79 101 125 53 53*
    113 92 183 54

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         
 104 115 83 27 26
    94 90 70 25
Test Chemical Diethylstilbestrol 
1.88      
 74 43 69 31 30
    93 53 78 28
  
3.75      
 57 35 114 67 55*
    70 23 91 43
  
7.5       
 65 17 97 50 45*
    92 47 110 40
  
15         
 60 17 175 97 86*
    48 22 108 74
  
30         
 66 13 134 68 78*
    48 14 128 88
Positive Control 3-Methylcholanthrene 
5         
 30 10 232 255 256*
    39 16 303 257
Negative Control Negative (Not Specified) 
 0         
 78 107 95 40 33*
    90 87 69 26

Induced S9 Trial: 2 Experiment Call: Equivocal
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 91 100 83 30 34
    93 94 102 37
Test Chemical Diethylstilbestrol 
5         
 63 20 91 48
  
10         
 89 19 98 37 43
    87 22 128 49
  
15         
 70 33 106 51 60*
    68 28 143 70
  
30         
 87 34 99 38 43
    76 24 107 47
  
40         
 61 13 105 57 55
    72 14 114 53
  
50         
   
Positive Control 3-Methylcholanthrene 
5         
 44 34 513 386 287*
    87 70 488 188
Negative Control Negative (Not Specified) 
 0         
 79 103 63 27 32*
    82 103 93 38

Induced S9 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         
 92 113 220 80 92
    85 93 266 105
Test Chemical Diethylstilbestrol 
2.5       
 90 86 161 60 66
    71# 62 155 73
  
5         
 92 51 352 128 126
    88 57 330 125
  
10         
 81# 28 450 185 173*
    75 23 361 161
  
20         
   
Positive Control 3-Methylcholanthrene 
5         
 44 18 350 268 268*
    49# 15 393 267
Negative Control Negative (Not Specified) 
 0         
 98 100 314 107 104*
    88# 95 264 100

Induced S9 Trial: 4 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 95 101 149 52 58
    80 96 119 50
    83 103 179 72
Test Chemical Diethylstilbestrol 
1.25      
 74 59 108 48 58
    63 44 122 64
    80 44 148 62
  
2.5       
 83# 41 134 54 58
    112 43 212 63
    90 36 152 56
  
5         
 99 21 170 57 72
    71 19 161 76
    76 19 190 83
  
30         
 60 16 268 148 142*
    63 18 277 146
    85 22 336 133
  
40         
 65 43 254 130 132*
    87 36 418 160
    87 48 274 105
  
50         
 86 35 358 139 151*
    89 33 363 136
    70 21 375 179
Positive Control 3-Methylcholanthrene 
5         
 66# 29 759 386 388*
    54 26 626 389

Induced S9 Trial: 5 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 96 89 114 40 40
    110 100 123 37
    102 103 126 41
    80 108 101 42
Test Chemical Diethylstilbestrol 
1.25      
 119 43 148 42 44
    94 42 130 46
  
2.5       
 90 42 117 43 39
    89 28 91 34
  
5         
 70 25 141 67 52
    102 32 112 37
  
10         
 84 23 149 59 64
    91 19 185 68
  
20         
   
Positive Control 3-Methylcholanthrene 
5         
 40 8 384 323 325*
    37 7 325 291
    36 8 383 360

Induced S9 Trial: 6 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 70 116 70 33 31
    69 88 71 34
    72 113 64 30
    67 82 56 28
Test Chemical Diethylstilbestrol 
1.25      
 61 72 40 22 33
    72 78 70 32
    79 69 105 45
  
2.5       
 74 66 71 32 31
    80 76 69 29
    63 63 61 32
  
5         
 65 59 60 31 29
    69 38 45 22
    80 50 84 35
  
10         
 55 43 65 39 47*
    62 43 98 52
    66 42 96 49
  
15         
 67 48 77 38 50*
    57 44 94 55
    56 51 97 58
  
20         
 135r 42 325 81
    204r 75 343 56
    192r 68 356 62
Positive Control 3-Methylcholanthrene 
5         
 35 20 305 288 287*
    33 20 314 322
    34 22 257 252

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