Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01389-0013-0000-7
Chemical Name:	3,3'-Dimethoxybenzidine dihydrochloride
CASRN:	20325-40-0
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	640872
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: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	45r	101	15	11	29
			42r	96	43	34
			50	107	44	29
			52	93	45	29
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	26	27	37	27	33	38
			42	70	63	51
			38	57	35	31
		33	27	44	26	32	44
			39	56	59	50
			36	45	55	51
		41	111#	136	48	14	45
			46	49	70	51
			39	44	79	68
		51	41	62	62	51	60*
			35	14	74	70	60*
		64	18	2	74	138	78*
			36	42	55	52
			34	25	46	45
Positive Control	Ethyl Methane Sulfonate	500	26	35	658	849	787*
			28	38	643	756
			28	43	639	756

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	61	98	103	56	58
			77	103	121	53
			69	99	143	69
			70	100	110	52
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	26	70	80	122	58	57
			69	82	118	57	57
		33	80	71	204	85	97*
			54	49	174	108	97*
		41	60	63	186	103	114*
			43	39	159	124	114*
		51	51	22	267	174	194*
			50	13	321	215	194*
		64	39	4	221	191	217*
			30	2	221	243	217*
		80

Positive Control	Ethyl Methane Sulfonate	500	41	44	829	674	667*
			45	42	882	658
			41	43	824	670

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	61	96	80	43	45
			57	98	76	45
			65	105	91	47
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	210	60#	100	88.5	49	61
			73	126	159	73	61
		262	71	107	91	43	75*
			63	85	203	108	75*
		328	58	51	159	91	91*
			49	70	133	91	91*
Positive Control	3-Methylcholanthrene	5	57	72	387	226	221*
Positive Control			54	70	348	216	221*

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	99	114	110	37	44
			88	98	136	52
			114	111	128	37
			80	78	117	49
Test Chemical	3,3'-Dimethoxybenzidine dihydrochloride	211	87	75	225	87	69*
			88	105	151	57
			98	117	186	63
		354	96	96	217	76	71*
			80	81	192	80
			97	92	170	58
		394	93	77	205	74	68*
			88	62	189	72
			103	100	184	60
		437	84	62	275	109	93*
			88	78	228	87
			80	78	204	85
		486	74r	64	196	88
		540	96	76	233	81	73*
			103	96	204	66
			90	81	192	71
		600	87	89	191	73	83*
			97	90	208	72
			89	73	276	104
Positive Control	3-Methylcholanthrene	5	69	41	787	378	429*
			60	34	630	353
			52	27	871	557

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