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Study Information
Study Attribute Value
CEBS Accession Number: 002-02679-0009-0000-5
Chemical Name: Phenylbutazone
CASRN: 50-33-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 421302
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:
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 110 100 78 24 36
    116 98 131 38
    125r 92 156 42
    111 102 152 46
Test Chemical Phenylbutazone 
200         
 89 170 96 36 29
    108 76 82 25
    116 104 87 25
  
300         
 89 78 93 35 36
    89 80 100 37
    95 75 106 37
  
400         
 96 65 89 31 33
    96 70 85 30
    87 69 103 40
  
500         
 111 38 189 57 85*
    98 28 270 92
    75 21 242 108
  
600         
 72 8 434 200 155*
    79 8 522 221
    104 60 134 43
  
800         
   
   
Positive Control Methyl Methane Sulfonate 
5         
 89 44 768 287 235*
    93 45 628 225
    85 50 488 191

Nonactivation Trial: 2 Experiment Call:
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 98 83 143 49 32
    108 97 75 23
    107 111 106 33
    93 109 63 23
Test Chemical Phenylbutazone 
200         
 101 87 90 30 30
    90 102 54 20
    88 89 104 39
  
300         
 80 70 92 38 32
    107 76 80 25
    102 93 99 32
  
400         
 113 74 104 31 37
    84 73 96 38
    106 66 136 43
  
500         
 99 65 120 40 38
    104 73 104 33
    90 42 106 39
  
600         
 113 103 117 35 47
    81 68 99 41
    90 52 179 67
Positive Control Methyl Methane Sulfonate 
5         
 72 53 439 203 243*
    72 55 586 271
    64 43 486 255

Induced S9 Trial: 1 Experiment Call:
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 70 81 74 35 38
    74 96 86 39
    75 118 97 43
    83 106 91 37
Test Chemical Phenylbutazone 
200         
 71 94 87 41 38
    82 109 83 34
    73 89 86 39
  
300         
 79 121 98 41 47
    75 95 106 47
    111 91 175 52
  
400         
 89 105 150 56 98*
    81 63 241 100
    91 48 376 138
  
500         
 319*
    106 42 546 172
    48 6 675 466
  
600         
   
   
Positive Control 3-Methylcholanthrene 
2.5       
 92# 98 472 170 202*
    87 57 568 218
    103 41 671 218

Induced S9 Trial: 2 Experiment Call:
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Acetone 
 0         
 113 102 91 27 30
    107 115 76 24
    99 90 94 32
    90 93 99 37
Test Chemical Phenylbutazone 
100         
 71 59 84 40 35
    97 70 81 28
    86 57 94 36
  
200         
 97 69 74 25 38
    84 72 128 51
    82 79 91 37
  
300         
 88 82 81 31 37
    80 85 98 41
    104 76 125 40
  
400         
 116 79 76 22 33
    85 52 101 40
    103 70 118 38
  
500         
 82 17 352 143 105*
    77 35 275 119
    97 51 156 54
Positive Control 3-Methylcholanthrene 
2.5       
 83 54 605 242 296*
    59 23 595 334
    62 21 577 310

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