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Study Information
Study Attribute Value
CEBS Accession Number: 002-02660-0002-0000-8
Chemical Name: Phenacetin
CASRN: 62-44-2
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 838305
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 Dimethyl Sulfoxide 
 0         
 79 84 83 35 23
    83# 109 40.5 16
    86 97 58 23
    83 109 46 19
Test Chemical Phenacetin 
62.5       
 75 71 53 24 21
    78# 74 30 13
    86# 87 66 26
  
125         
 98 75 55 19 24
    78 66 69 30
  
250         
 82 62 61 25 20
    91 77 46 17
    117 97 69 20
  
500         
 79 57 60 25 25
    83 75 65 26
    82 66 56 23
  
750         
 85 83 64 25 25
    114 66 69 20
    87 68 79 30
  
1000         
 77 34 41 18 18
    113 63 60 18
Positive Control Ethyl Methane Sulfonate 
250         
 54# 32 1054.5 651 543*
    62 46 964 520
    75 51 1035 458

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         
 112 113 94 28 23
    95 99 56 20
    95 102 64 22
    82 85 54 22
Test Chemical Phenacetin 
125         
 90 85 47 18 19
    88# 78 55.5 21
    89 88 50 19
  
250         
 99 74 82 28 24
    82 68 57 23
    97 58 65 22
  
500         
 82 60 70 29 26
    91 72 80 29
    88 80 53 20
  
1000         
 82 23 73 30 34
    101 51 104 34
    82 49 95 39
  
1500         
   
    49 5 148 102
  
2000         
   
   
Positive Control Ethyl Methane Sulfonate 
250         
 46 25 689 499 626*
    43 28 637 498
    24 13 622 882

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 Dimethyl Sulfoxide 
 0         
 96 94 80 28 25
    97 101 89 31
    105# 92 69 22
    101 112 62 21
Test Chemical Phenacetin 
125         
 102 94 70 23 23
    93 58 68 24
    71 65 49 23
  
250         
 96 71 67 23 25
    94 58 69 25
    95 72 75 26
  
500         
 110 100 81 25 23
    96 68 60 21
    106 86 78 25
  
1000         
 99 54 102 34 35
    111 72 113 34
    90 62 96 36
  
1500         
 103# 64 85.5 28 49*
    95 19 219 77
    86 31 112 43
  
2000         
 103 32 154 50 65*
    79 9 163 69
    82 10 186 76
Positive Control Ethyl Methane Sulfonate 
250         
 86 48 824 319 344*
    92 62 805 293
    69 52 869 421

Non-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 Dimethyl Sulfoxide 
 0         
 58 101 72 41 35
    62 97 63 34
    73 101 62 28
Test Chemical Phenacetin 
250         
 54# 52 63 39 38
    49 71 56 38
    59 87 65 37
  
500         
 56# 81 64 38 38
    57 69 72 42
    68 60 67 33
  
750         
 66 59 108 54 52
    48 86 86 60
    48 72 61 42
  
1000         
 88# 102 113 43 42
    80 108 97 41
  
1500         
 69# 45 105 51 60*
    80 29 177 74
    66 69 111 56
  
2000         
 89# 15 233 87 88*
    64 15 138 72
    74 9 228 103
Positive Control 3-Methylcholanthrene 
3.5       
 62 64 304 164 186*
    58 57 364 209

Induced S9 Trial: 1 Experiment Call: Inconclusive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 76 104 54 24 33
    83 122 46 19
    82 93 115 47
    71 81 90 42
Test Chemical Phenacetin 
62.5       
 68# 80 75 37 37
    63 71 88 47
    93 119 80 29
  
125         
 80 88 75 31 38
    70 93 73 35
    60 69 87 48
  
250         
 80 82 113 47 43
    72# 88 96 44
    64# 83 72 38
  
500         
 88 82 137 52
  
750         
 76# 68 129 57 49*
    80 105 98 41
    73# 80 109.5 50
  
1000         
 98 72 161 55 67*
    30 28 107 118
    58# 73 51 29
Positive Control 3-Methylcholanthrene 
2.5       
 35# 17 544.5 516 367*
    57 39 492 290
    49 35 438 296

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 Dimethyl Sulfoxide 
 0         
 92 86 71 26 18
    107 97 42 13
    108 116 48 15
    122r 102 67 18
Test Chemical Phenacetin 
125         
 103 89 57 18 20
    110 95 53 16
    101 61 74 24
  
250         
 117 75 73 21 23
    103 73 78 25
    101 100 72 24
  
500         
 95# 80 82.5 29 27
    78 56 55 24
    87 76 74 29
  
1000         
 98 75 90 31 27
    114 71 78 23
    111 76 87 26
  
1500         
 110 22 88 27 30*
    98 51 77 26
    84 41 91 36
  
2000         
 78 33 70 30 27
    91 35 90 33
    105 28 60 19
Positive Control 3-Methylcholanthrene 
2.5       
 86 49 450 174 155*
    86 61 392 152
    85 53 352 139

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