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Study Information
Study Attribute Value
CEBS Accession Number: 002-02667-0008-0000-1
Chemical Name: Phenformin hydrochloride
CASRN: 834-28-6
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 075668
Study Result: Equivocal


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: Equivocal
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 78 106 126 54 65
    68 108 144 71
    87 102 160 61
    76 85 168 73
Test Chemical Phenformin hydrochloride 
100         
 84 83 177 70 73
    83# 71 190.5 77
  
200         
 72 72 191 89 81
    82 63 183 74
  
400         
 61 60 163 89 86
    64 59 159 82
  
800         
 68 37 226 111 97
    87 38 216 83
  
1600         
 73 7 213 98 111*
    51 6 188 124
Positive Control Methyl Methane Sulfonate 
15         
 31 20 509 541 468*
    42 21 494 394

Nonactivation Trial: 2 Experiment Call: Equivocal
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 102 89 95 31 30
    92 99 87 31
    86 105 80 31
    99 106 82 28
Test Chemical Phenformin hydrochloride 
800         
 76 32 127 55 46
    73 36 78 36
  
900         
 73 20 114 52 45
    58 20 66 38
  
1000         
 78# 11 92 39 43
    72 10 102 47
  
1100         
 64 6 93 49 47
    69 5 95 46
  
1200         
 60 4 145 80 62*
    66 5 86 44
  
1300         
   
Positive Control Methyl Methane Sulfonate 
15         
 30# 24 166.5 186 170*
    37 21 170 155

Induced S9 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         
 76 98 151 67 61
    90 92 127 47
    80 106 150 63
    68 105 135 67
Test Chemical Phenformin hydrochloride 
600         
 73 36 108 49 53
    64 37 111 58
  
800         
 53 28 82 51 60
    57 30 118 69
  
1000         
 61 17 121 66 73
    74 19 178 81
  
1200         
   
Positive Control 3-Methylcholanthrene 
2.5       
 37 11 527 473 472*
    37 14 527 471

Induced S9 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         
 79 95 70 29 30
    79 98 71 30
    74 91 68 31
    75 116 68 30
Test Chemical Phenformin hydrochloride 
300         
 66 48 88 44 31
    62 39 34 18
  
500         
 62 25 54 29 28
    58 20 48 28
  
700         
 48 16 75 52 45
    56 12 63 37
  
900         
 45 7 46 34 27
    33 7 19 19
  
1100         
  
1300         
   
Positive Control 3-Methylcholanthrene 
2.5       
 43 30 425 332 334*
    51 33 513 336

Induced S9 Trial: 3 Experiment Call: Inconclusive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 76 112 98 43 44
    77 88 113 49
    80 101 106 44
    59 99 68 39
Test Chemical Phenformin hydrochloride 
607         
 70 89 64 30 34
    81 103 91 37
  
780         
 73 73 70 32 31
    98 37 90 31
  
953         
 95 65 51 18 18
    101 63 52 17
  
1127         
 84 57 39 16 21
    84 52 66 26
  
1300         
 100 35 103 34 29
    78 38 54 23
Positive Control 3-Methylcholanthrene 
2.5       
 46 39 571 414 392*
    51 39 567 369

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