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Study Information
Study Attribute Value
CEBS Accession Number: 002-02165-0012-0000-9
Chemical Name: Ethylene thiourea (ETU)
CASRN: 96-45-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 669405
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: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 86 102 78 30 37
    86 96 83 32
    83 100 79 32
    99 103 157 53
Test Chemical Ethylene thiourea (ETU) 
225         
 92 99 93 34 33
    102# 108 99 33
  
450         
 95 96 101 36 28
    94 107 58 21
  
900         
 73 85 72 33
  
1800         
 63# 80 97 51 46
    71# 67 86 40
  
3600         
 64# 74 85 44 36
    92# 89 76 28
Positive Control Other Positive Control 
15         
 36 21 196 181 154*
    35 24 132 126

Nonactivation Trial: 2 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         
 80 116 54 23 26
    69 92 40 19
    69 93 65 31
    79# 99 69 29
Test Chemical Ethylene thiourea (ETU) 
225         
 83# 111 38 15 21
    90 104 71 26
  
450         
 90 114 49 18 19
    82 109 48 20
  
900         
 86 102 44 17 17
    102 96 55 18
  
1800         
 90 98 36 13 15
    86 96 41 16
  
3600         
 78 98 42 18 16
    84# 104 35 14
Positive Control Methyl Methane Sulfonate 
15         
 44 35 172 130 126*
    43 37 157 122

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         
 77 101 46 20 17
    63 107 28 15
    71 111 27 13
    61 81 36 20
Test Chemical Ethylene thiourea (ETU) 
225         
 61 87 53 29 25
    63 97 39 21
  
450         
 73 109 35 16 17
    65 104 37 19
  
900         
 68 68 51 25 26
    82 92 66 27
  
1800         
 91 118 98 36 35*
    73 97 73 33
  
3600         
 83 102 81 33 35*
    85 98 94 37
Positive Control 3-Methylcholanthrene 
2.5       
 51 32 195 128 130*
    56 32 223 132

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         
 72 95 51 24 23
    82 106 47 19
    86 104 71 28
    69 96 45 22
Test Chemical Ethylene thiourea (ETU) 
1200         
 84 109 72 29 25
    72 95 48 22
  
1800         
 84 89 88 35 37*
    87 87 103 40
  
2400         
 75 77 97 43 40*
    65 69 73 38
  
3000         
 73 92 104 47 46*
    78 71 103 44
  
3600         
 73 80 124 56 55*
    70 68 113 54
Positive Control 3-Methylcholanthrene 
2.5       
 47 25 418 300 269*
    69 29 490 238

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