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Study Information
Study Attribute Value
CEBS Accession Number: 002-02114-0008-0000-8
Chemical Name: Endrin
CASRN: 72-20-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 242024
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: Inconclusive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 78 102 129 55 44
    87 108 100 39
    97 93 108 37
    110 97 152 46
Test Chemical Endrin 
5         
 85 100 86 34 41
    76 82 110 48
  
10         
 72 60 101 47 39
    94 111 85 30
  
20         
 79 55 98 41 45
    64 56 93 48
  
40         
 70 55 102 49 52
    72 59 121 56
  
80         
 71 45 130 61 51
    68 48 84 41
Positive Control Methyl Methane Sulfonate 
15         
 29 19 186 218 187*
    37 22 172 156

Nonactivation Trial: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 112 105 210 63 66
    102 99 225 73
    112 110 205 61
    91 87 177 65
Test Chemical Endrin 
20         
 99 76 278 94 88
    102 89 250 82
  
40         
 83 74 293 117 98
    110 98 261 79
  
60         
 102 86 300 98 92
    118 86 303 85
  
80         
 93 70 333 119 127*
    97 73 389 134
  
100         
 125r 76 415 111
    85 57 168 66
Positive Control Methyl Methane Sulfonate 
15         
 54 28 256 158 145*
    56 34 224 133
Methyl Methane Sulfonate 
250         
 86 79 138 54 71
    97 79 255 87

Nonactivation Trial: 3 Experiment Call: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 79 94 59 25 24
    79 105 66 28
    76 95 58 25
    86 105 45 17
Test Chemical Endrin 
20         
 79 58 36 15 16
    91 61 44 16
  
40         
 74 52 44 20
    124r 61 77 21
  
60         
 70 65 52 25 28
    73 51 68 31
  
80         
 99 80 55 19 21
    83# 50 57 23
  
100         
 76 56 51 22 21
    80 65 47 20
Positive Control Methyl Methane Sulfonate 
15         
 48 35 127 89 92*
    43 34 122 95

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 Acetone 
 0         
 109 109 114 35 34
    108 99 114 35
    91 92 92 34
    96 100 93 32
Test Chemical Endrin 
20         
 121r 81 136 38
    113 83 162 48
  
40         
 101 78 91 30 33
    80 79 86 36
  
60         
 90 80 159 59 48
    89 83 100 37
  
80         
 115 78 102 30 32
    103 70 109 35
  
100         
 117 96 107 31 32
    99 85 97 33
Positive Control Methyl Methane Sulfonate 
15         
 48 41 168 117 108*
    70 38 206 98
Methyl Methane Sulfonate 
250         
 83 67 598 240 215*
    86 85 493 190

Induced S9 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 Acetone 
 0         
 50 84 89 59 45
    60 108 66 37
    69 94 91 44
    72 115 88 41
Test Chemical Endrin 
20         
 72 78 98 45 42
    69 79 78 38
  
40         
 54 70 63 39 44
    49 74 73 50
  
60         
 60 70 81 45 46
    61 69 84 46
  
80         
 92 102 116 42 37
    83 102 82 33
  
100         
 93 119 96 35 32
    100 117 88 29
Positive Control 3-Methylcholanthrene 
2.5       
 33 15 449 451 502*
    38 20 632 552

Induced S9 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 Acetone 
 0         
 64 111 61 32 33
    57 97 100 58
    55 93 32 19
    72 99 50 23
Test Chemical Endrin 
20         
 47 69 52 37 36
    53 91 55 35
  
40         
 54 75 69 43 46
    56 83 82 49
  
60         
 49 66 80 55 49
    49 64 65 44
  
80         
 60 58 66 37 38
    55 74 64 39
  
100         
 60 66 68 38 42
    51 46 72 47
Positive Control 3-Methylcholanthrene 
2.5       
 19 7 260 464 445*
    25 7 320 427

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