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Study Information
Study Attribute Value
CEBS Accession Number: 002-02042-0032-0000-5
Chemical Name: Diethylstilbestrol
CASRN: 56-53-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 384132
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 Ethanol 
 0         
 40r 51 77 65 33
    45r 97 67 50
    62 100 53 28
    57 100 65 38
Test Chemical Diethylstilbestrol 
12.5       
 48 69 77 54 51
    62 71 112 61
    55 45 64 39
  
25         
 41 45 84 68 175*
    34 6 407 395
    47 53 87 62
  
50         
 57 10 199 116 92*
    74 7 190 85
    52 6 116 75
  
100         
 40 7 113 95 61*
    61 29 71 39
    45 19 66 49
  
150         
   
   
  
200         
 59 6 173 98 88*
    60 9 159 88
    54# 18 125 77
Positive Control Methyl Methane Sulfonate 
10         
 7r 2 222 1057
    9r 3 261 1004
    9r 2 260 945

Nonactivation Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Ethanol 
 0         
 120 119 87 24 30
    83 85 83 33
    83 96 80 32
Test Chemical Diethylstilbestrol 
12.5       
 75 34 125 56 50*
    93# 56 123 44
    220r 94 310 47
  
25         
 86 13 141 55 79*
    79# 10 245 104
  
50         
 96# 7 217 75 69*
    96 22 167 58
    81# 14 178 74
  
75         
 56*
    92# 12 149 54
    94 15 165 59
  
100         
   
    90 12 152 56
  
150         
   
   
Positive Control Methyl Methane Sulfonate 
5         
 62 47 374 201 226*
    56 43 379 228
    71 40 529 250

Nonactivation Trial: 3 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Ethanol 
 0         
 97 73 91 31 27
    87 126 65 25
    76 100 56 25
Test Chemical Diethylstilbestrol 
12.5       
 98 64 107 36 36
    77 92 85 37
    91 69 94 35
  
25         
  
50         
 89 21 89 33 40
    86 28 109 42
    79 27 102 43
  
75         
 63 7 143 76 73*
    77# 9 161 70
  
100         
   
   
Positive Control Methyl Methane Sulfonate 
5         
 128r 80 599 156 174*
    88 116 422 160
    103# 95 580 188

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