Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01389-0014-0000-8
Chemical Name:	3,3'-Dimethoxybenzidine dihydrochloride
CASRN:	20325-40-0
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	948661
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: Equivocal
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	97	93	60	21	25
			93	105	83	30
			80	97	65	27
			91	104	64	24
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	40	75	56	49	22	20
			57	84	26	15
			75	62	55	24
		50	86	58	48	19	19
			53#	49	27	17
			90	76	55	20
		60	79	56	48	20	19
			70#	49	30	14
			62	54	41	22
		70	62	26	47	25	29
			63	25	63	33	29
		80	56	13	54	32	35
			52#	10	66	42
			48	10	45	32
		90	51	6	71	46	43*
			63	10	56	29
			55	8	86	52
Positive Control	Ethyl Methane Sulfonate	500	27	11	660	810	953*
			34	18	908	886
			20	9	680	1162

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	84	109	67	27	27
			94	91	77	27
			165r	178	54	11
			125r	150	51	14
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	40	61	58	42	23	28
			90	54	91	34
			83	90	69	28
		50	87	59	47	18	29
			51	32	65	43
			70	60	57	27
		60	96	32	120	42	61*
			73	28	119	55
			42	7	108	85
		70	59	10	131	74	74*
			59	16	116	66
			70	10	176	84
		80	50#	13	92	61	72*
			74	12	139	63
			53	7	146	92
Positive Control	Ethyl Methane Sulfonate	250	79	69	743	314	283*
			109	77	761	233
			89#	70	807	303

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	9r	9	37.5	134	13
			85	107	25	10
			71	93	33	16
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	40	82	48	35	14	14
			91	60	30	11
			82	54	42	17
		50	70	29	38	18	17
			72#	34	36	17
			68	48	31	15
		60	61	20	48	26	22
			76	26	40	17	22
		70	58	3	136	78	59*
			78#	8	94.5	40	59*
		80

			68	5	101	50
		90


Positive Control	Ethyl Methane Sulfonate	250	60	61	617	346	674*
			20	16	781	1302
			55	47	622	375

Nonactivation Trial: 4 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	103	90	53	17	22
			94	98	70	25
			96	103	72	25
			88	110	60	23
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	40	83	70	62	25	26
			100	74	45	15
			53	47	62	39
		50	97	59	75	26	22
			85	64	41	16
			92	77	65	24
		60	75	43	75	33	37*
			77	26	104	45
			94	44	89	32
		70	93	45	94	34	30
			81	38	72	30
			70	45	54	26
		80	52	7	96	62	61*
			49	5	99	67
			71	9	116	54
		90	37	2	85	76	66*
			43	4	101	79
			60	14	76	42
Positive Control	Ethyl Methane Sulfonate	250	64	55	842	439	380*
			80	57	808	339
			80	64	868	363

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	82	97	95	39	36
			86	105	76	30
			92	88	115	42
			102	110	103	34
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	4.7	98	103	120	41	36
			87	86	80	31	36
		9.4	85	95	108	42	39
			87	85	93	36	39
		18.8	63	77	84	44	48
			86	81	133	52	48
		37.5	91	90	126	46	46
			90	103	122	45	46
		75	65	73	130	66	63*
			87	105	157	60	63*
		150	118	90	149	42	64*
			79	75	203	85	64*
Positive Control	3-Methylcholanthrene	5	24	2	256	353	338*
			30	3	277	304
			25	2	267	356

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	89	113	87	33	29
			70	114	69	33
			87	91	51	19
			70	82	62	30
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	100	65	74	102	52	55*
			62	61	102	55
			70	71	121	58
		125	52	83	71	46	53*
			57	76	88	52
			55	70	101	62
		150	67	66	104	52	49*
			68	62	126	62
			54	62	53	33
		200	63	56	90	48	45*
			89	32	118	44
			62	58	79	42
		250	76	64	143	63	62*
			60	70	100	56
			54	48	107	66
Positive Control	3-Methylcholanthrene	5	23	5	167	244	272*
			24	4	203	282
			26	4	224	289

Induced S9 Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Solvent	0	93	107	57	20	17
			77	130	38	16
			76	89	25	11
			72	73	41	19
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	50	72	67	79	37	33*
			78	80	80	34
			74#	96	60	27
		100	69#	59	94.5	46	37*
			82	50	72	29
			63#	66	66	35
		150	87	95	92	35	37*
			93	70	120	43
			63	72	62	33
		200	61	57	84	46	36*
			50	64	56	37
			86	90	67	26
		250	66	80	60	30	37*
			65	74	73	38
			56	45	71	42
		300	52	29	57	36	32*
			60	63	46	25
			64	44	69	36
			60	47	58	32
Positive Control	3-Methylcholanthrene	2.5	54	44	299	183	188*
			69	41	405	196
			61#	52	342	186

Induced S9 Trial: 4 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	94	83	99	35	34
			133r	113	114	29
			108	112	101	31
			110	105	115	35
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	50	98	94	164	56	60*
			96	89	168	58
			103	73	204	66
		100	130r	97	203	52	59*
			113#	100	193.5	57
			96	71	176	61
		200	80	42	171	71
		250	128r	98	187	49	62*
			109#	77	234	71
			118	82	189	53
		300	85#	65	217.5	86	82*
			98	57	235	80
			104#	59	253.5	81
		400					132*
			72	10	365	169
			82	13	232	95
		500


Positive Control	3-Methylcholanthrene	2.5	85	17	628	247	440*
			34	4	398	394
			27#	3	546	678

Induced S9 Trial: 5 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	87#	96	75	29	29
			110	124	63	19
			97	93	91	31
			78#	87	85.5	37
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	50	90	87	183	68	62*
			97	90	150	51
			95	92	186	66
		100	84	97	149	59	66*
			90	93	184	69
			74	76	155	70
		200	102	103	176	58	67*
			90	71	204	76
			120r	104	169	47
		250	101	79	162	53	58*
			96	75	162	56
			92	63	181	66
		300	90	48	149	55	64*
			63	46	122	65
			64	57	138	72
			83	58	154	62
		400	102	30	237	78	100*
			52	12	195	126
			74	12	253	114
			72	18	176	82
Positive Control	3-Methylcholanthrene	2.5	52	34	388	250	257*
			59	33	519	293
			64#	40	435	228

Induced S9 Trial: 6 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	72#	71	52	24	20
			87	129	42	16
			87	96	55	21
			85	105	46	18
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	50	57#	64	63	37	35*
			60	74	67	37
			43	43	40	31
		100	69	50	110	54	48*
			53	60	83	52
			65	64	76	39
		200	45	50	69	51	52*
			51#	45	67	44
			43	45	78	60
		250	67	61	81	40	38*
			74	72	95	43
			90	70	81	30
		300	57	58	73	43	46*
			56	53	71	42
			75#	57	112.5	50
			57	60	84	49
		400	72	55	127	59	49*
			74	50	86	39	49*
Positive Control	3-Methylcholanthrene	2.5	76#	70	349.5	154	159*
			55#	55	282	171
			92	54	425	153

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