Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01694-0013-0000-6
Chemical Name:	Benzidine dihydrochloride
CASRN:	531-85-1
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	011624
Study Result:	Positive

View Study Details | View Protocol | Download To Excel

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	Water	0	59	96	100	56	59
			61	95	105	57
			64	114	139	73
			61	95	89	49
Test Chemical	Benzidine dihydrochloride	13	49	80	128	87	68
			61	100	91	49	68
		26	42	59	83	67	80
			49	66	135	92	80
		51	46	32	158	114	121*
			51	31	195	128	121*
		64	28	6	156	186	175*
			38	16	186	165	175*
		80	26	5	140	176	192*
			23	5	145	209	192*
Positive Control	Ethyl Methane Sulfonate	500	36	36	534	499	442*
			39	45	499	423
			37	41	446	405

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	61	100	134	73	62
			64	100	114	60
			59	100	98	56
			65	99	121	62
Test Chemical	Benzidine dihydrochloride	26	49	66	109	75	68
			65	82	120	61	68
		33	67	69	135	68	62
			70	73	119	57	62
		41	57	40	131	77	93
			59	44	191	108	93
		51	41	15	171	138	148*
			36	13	171	158	148*
		64	19	3	131	232
		80

Positive Control	Ethyl Methane Sulfonate	500	39	37	663	564	619*
			40	41	716	602
			34	36	697	690

Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	60	108	156	87	71
			61	97	119	65
			56	93	115	69
			58	102	110	63
Test Chemical	Benzidine dihydrochloride	13	57	90	122	72	66
			53	85	97	61	66
		26	50	60	52	35	60
			71	74	183	86	60
		51	50	13	175	117	148*
			33	10	174	178	148*
		64	16	3	53	108	169*
			25	4	174	229	169*
		80	9r	1	146	551
		100	9r	1	100	364
			7r	1	85	386
Positive Control	3-Methylcholanthrene	6	21	8	313	505	488*
			17	5	221	438
			17	6	266	522

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	107	97	315	99	97
			102	89	322	105
			106	106	256	80
			117	107	364	104
Test Chemical	Benzidine dihydrochloride	11.37	84#	77	373	148	135
			110	93	403	122	135
		22.73	87	73	394	151	130
			99	83	322	109	130
		45.47	70	30	1088	521	510*
			67	29	1008	500	510*
		56.83	26	4	903	1180	1041*
			33	6	901	901	1041*
		71.04

Positive Control	3-Methylcholanthrene	5	55	26	827	498	526*
			49#	21	838.5	576
			65	28	979	503

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