Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01698-0007-0000-3
Chemical Name:	Benzo(a)pyrene
CASRN:	50-32-8
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	G14533
Study Result:	Positive

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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 and Non-Toxic
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	60	88	43	24	27
Vehicle Control			69	107	62	30	27
Test Chemical	Benzo(a)pyrene	7.5	54	82	42	26	26
			74	90	57	26	26
		15	65	59	78	40	36
			62	99	60	32	36
		30	53	67	56	35	42
			50	79	74	49	42
		60	86	85	83	32	31
			70	75	64	30	31
		100	51	66	66	43	40
			58	61	63	36	40
Positive Control	Ethyl Methane Sulfonate	500	37	18	477	432	429*
Positive Control			43	28	552	426	429*
Negative Control	Negative (Not Specified)	0	51	102	58	38	31*
Negative Control			62	103	46	25	31*

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	71#	92	85.5	40
Test Chemical	Benzo(a)pyrene	7.5	70#	91	82.5	39	40
			64#	94	78	41	40
		15	97	94	64	22	22
			82	101	56	23	22
		30	71	92	102	48	39
			75#	67	67	30	39
		60	83#	83	84	34	37
			77#	85	94.5	41	37
		100	84	78	78	31	34
			81	67	89	37	34
Positive Control	Ethyl Methane Sulfonate	500	48#	56	672	463	474*
Positive Control			48#	53	691	485	474*
Negative Control	Negative (Not Specified)	0	76#	109	84	37	33*
Negative Control			73	99	65	30	33*

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	Dimethyl Sulfoxide	0	91	108	82	30	30
			95	98	67	23
			87	93	101	39
			103	100	82	27
Test Chemical	Benzo(a)pyrene	0.938	112	135	62	18	18
			102	103	54	18
			80#	95	40	17
		1.88	88	119	36	14	17
			93	93	67	24
			87	117	39	15
		3.75	124r	119	52	14	15
			93	106	39	14
			115	128	57	17
		7.5	116	97	66	19	16
			87	117	36	14
			121r	106	78	22
		15	100	105	61	20	18
			100	91	36	12
			97	83	64	22
		30	125r	98	62	17	21
			86	79	72	28
			79	64	34	14
Positive Control	Ethyl Methane Sulfonate	500	55	27	661	399	486*
			46	16	785	569
			50	26	732	490

Non-Induced S9 Trial: 1 Experiment Call: No Call
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	50	91	138	92	84
Vehicle Control			52#	92	121	77	84
Test Chemical	Benzo(a)pyrene	7.5	68	81	341	167	179*
			68	56	389	192	179*
		15	61#	52	429	234	247*
			61	42	475	260	247*
		30	46	54	521	380	388*
			46	30	549	395	388*
		60	35	10	571	539	501*
			37	17	519	463	501*
		100	19	4	388	669	719*
			20	3	454	769	719*
Positive Control	3-Methylcholanthrene	5	53	26	318	199	225*
Positive Control			68	56	517	252	225*
Negative Control	Negative (Not Specified)	0	62	99	100	53	51*
Negative Control			73	118	106	48	51*

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	106	151	116	36	39
Vehicle Control			93	111	118	42	39
Test Chemical	Benzo(a)pyrene	1.88	90	26	675	250	255*
			97	49	753	260	255*
		2.5	88	30	572	217	238*
			70	40	542	258	238*
		3.75	67	22	487	241	297*
			50	21	526	353	297*
		5	67	28	448	222	230*
			66	16	473	238	230*
		7.5	47	7	430	305	339*
			41	8	463	373	339*
Positive Control	3-Methylcholanthrene	5	77	18	546	237	225*
Positive Control			76	47	484	213	225*
Negative Control	Negative (Not Specified)	0	115	81	142	41	45*
Negative Control			86	57	125	48	45*

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	101	103	327	108	106
Vehicle Control			93	92	289	104	106
Test Chemical	Benzo(a)pyrene	0.156	86	82	313	122	116
			99	117	327	110	116
		0.313	94	80	376	134	139
			97	84	423	145	139
		0.625	83	45	531	214
			132r	78	500	126
		1.25	60	21	434	243	292*
			69	11	707	342	292*
		2.5

Positive Control	3-Methylcholanthrene	5					513*
Positive Control			31	3	472	513	513*
Negative Control	Negative (Not Specified)	0	113	110	296	87	93*
Negative Control			114	95	334	98	93*

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	88	111	60	23	30
			72	103	57	27
			70	93	70	34
			73	93	84	39
Test Chemical	Benzo(a)pyrene	0.25	84	118	161	64	63*
			94	127	172	61	63*
		0.5	89	103	235	88	91*
			72	119	204	94	91*
		1	72	65	240	111	130*
			69	70	309	149	130*
		2	71	27	274	129	134*
			87	20	359	138	134*
		4

Positive Control	3-Methylcholanthrene	5	54	33	380	234	236*
			58	41	389	223
			48	26	356	250

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