Government Funding Lapse

Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted. The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit  cc.nih.gov. Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Study Information
Study Attribute Value
CEBS Accession Number: 002-01698-0008-0000-4
Chemical Name: Benzo(a)pyrene
CASRN: 50-32-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: G58760
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
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 67 111 118 58 65
    63 89 134 71
Test Chemical Benzo(a)pyrene 
84.4       
 58 96 150 86 74
    51 84 94 62
  
113         
 38 69 87 76 60
    58 91 77 45
  
150         
 65 106 180 93 91
    47 78 126 89
  
200         
 51 71 125 82 81
    49# 73 116 80
  
400         
 52 70 146 93 91
    46 62 124 90
Positive Control Ethyl Methane Sulfonate 
500         
 11 11 560 1723 1204*
    28 25 576 686

Nonactivation Trial: 2 Experiment Call: Negative
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 66 90 130 65 65
    77 110 151 66
Test Chemical Benzo(a)pyrene 
15.6       
 79 109 159 68 65
    78 116 147 63
  
31.3       
 78 116 120 52 52
    75 106 116 52
  
62.5       
 129r 178 107 28
    79 115 107 45
  
125         
 71# 84 123 58
  
250         
 78 71 144 62 61
    85 83 156 61
  
500         
 63 69 138 73 66
    82 83 144 59
Positive Control Ethyl Methane Sulfonate 
500         
 42 40 553 435 446*
    42 39 571 457

Non-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         
 83 110 176 71 77
    82 90 205 84
Test Chemical Benzo(a)pyrene 
 0.93      
 69 76 218 106 97
    81 88 216 89
  
1.6       
 64 70 232 120 117
    76 72 259 114
  
2.6       
 77 80 368 159 159*
    63 56 300 159
  
4.3       
 65 67 413 213 213*
    64 68 407 213
  
7.2       
 71 66 420 197 224*
    53 47 402 251
  
12         
 48 40 412 287 283*
    53 35 445 278
  
20         
 42 22 446 358 367*
    40 23 448 376
Positive Control 3-Methylcholanthrene 
7         
 45 40 462 343 294*
    57 48 420 245

Non-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         
 97 107 244 84 79
    96 93 214 74
Test Chemical Benzo(a)pyrene 
2.6       
 60 75 388 216 217*
    71 72 461 217
  
4.3       
 69 86 529 256 256*
    63 68 483 256
  
7.2       
 36 23 526 489 455*
    44 18 556 421
  
12         
 26 8 463 594 593*
    26 9 468 592
  
20         
 17 4 352 690 666*
    17 3 331 643
  
33.3       
 14 3 400 964 907*
    13 2 327 849
Positive Control 3-Methylcholanthrene 
7         
 49 35 437 300 311*
    48 35 463 323

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         
 95 86 132 46 48
    102 114 153 50
Test Chemical Benzo(a)pyrene 
3.3       
 90 82 262 97 110*
    68 59 249 123
  
4.1       
 75 54 358 158 151*
    82 65 351 143
  
5.1       
 76 48 398 175 175*
    71 50 373 175
  
6.4       
 56 23 465 278 245*
    64 32 410 213
  
8         
 49 13 380 257 294*
    47 10 464 331
Positive Control 3-Methylcholanthrene 
5         
 75 65 414 184 197*
    69 59 434 211

Induced S9 Trial: 3 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 111 121 159 48 58
    104# 106 162 52
    92 78 181 66
    101 94 203 67
Test Chemical Benzo(a)pyrene 
2.6       
 102 92 478 156 162*
    91 69 462 169
  
3.3       
 62 54 541 292 242*
    99 92 572 193
  
4.1       
 62 45 583 315 294*
    71 45 575 272
  
5.12      
 61 32 560 304 325*
    58 32 607 346
  
6.4       
 51 13 576 379 363*
    58 16 609 347
  
8         
   
Positive Control 3-Methylcholanthrene 
5         
 61 16 429 233 283*
    51 25 494 326
    55 25 479 289

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