Genetic Toxicology - Mammalian Cell Mutagenicity

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

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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
		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
Vehicle Control			63	89	134	71	65
Test Chemical	Benzo(a)pyrene	84.4	58	96	150	86	74
			51	84	94	62	74
		113	38	69	87	76	60
			58	91	77	45	60
		150	65	106	180	93	91
			47	78	126	89	91
		200	51	71	125	82	81
			49#	73	116	80	81
		400	52	70	146	93	91
			46	62	124	90	91
Positive Control	Ethyl Methane Sulfonate	500	11	11	560	1723	1204*
Positive Control			28	25	576	686	1204*

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
Vehicle Control			77	110	151	66	65
Test Chemical	Benzo(a)pyrene	15.6	79	109	159	68	65
			78	116	147	63	65
		31.3	78	116	120	52	52
			75	106	116	52	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	61
		500	63	69	138	73	66
			82	83	144	59	66
Positive Control	Ethyl Methane Sulfonate	500	42	40	553	435	446*
Positive Control			42	39	571	457	446*

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

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

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

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	162*
		3.3	62	54	541	292	242*
			99	92	572	193	242*
		4.1	62	45	583	315	294*
			71	45	575	272	294*
		5.12	61	32	560	304	325*
			58	32	607	346	325*
		6.4	51	13	576	379	363*
			58	16	609	347	363*
		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